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Khojastehnia, Mahdi. "Massive MIMO Channels Under the Joint Power Constraints." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/39992.
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Massive MIMO has been recognized as a key technology for 5G systems due to its high spectral efficiency. The capacity and optimal signaling for a MIMO channel under the total power constraint (TPC) are well-known and can be obtained by the water-filling (WF) procedure. However, much less is known about optimal signaling under the per-antenna power constraint constraint (PAC) or under the joint power constraints (TPC+PAC). In this thesis, we consider a massive MIMO Gaussian channel under favorable propagation (FP) and obtain the optimal transmit covariance under the joint constraints. The effect of the joint constraints on the optimal power allocation (OPA) is shown. While it has some similarities to the standard WF, it also has number of notable differences. The numbers of active streams and active PACs are obtained, and a closed-form expression for the optimal dual variable is given. A capped water-filling interpretation of the OPA is given, which is similar to the standard WF, where a container has both floor and ceiling profiles. An iterative water-filling algorithm is proposed to find the OPA under the joint constraints, and its convergence to the OPA is proven.
The robustness of optimal signaling under FP is demonstrated in which it becomes nearly optimal for a nearly favorable propagation channel. An upper bound of the sub-optimality gap is given which characterizes nearly (or eps)-favorable propagation. This upper bound quantifies how close the channel is to the FP.
A bisection algorithm is developed to numerically compute the optimal dual variable. Newton-barrier and Monte-Carlo algorithms are developed to find the optimal signaling under the joint constraints for an arbitrary channel, not necessarily for a favorable propagation channel.
When the diagonal entries of the channel Gram matrix are fixed, it is shown that a favorable propagation channel is not necessarily the best among all possible propagation scenarios capacity-wise.
We further show that the main theorems in [1] on favorable propagation are not correct in general. To make their conclusions valid, some modifications as well as additional assumptions are needed, which are given here.
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Liu, Xingsheng. "Processing and Reliability Assessment of Solder Joint Interconnection for Power Chips." Diss., Virginia Tech, 2001. http://hdl.handle.net/10919/26691.
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Circuit assembly and packaging technologies for power electronics have not kept pace with those for digital electronics. Inside those packaged power devices as well as the state-of-the-art power modules, interconnection of power chips is accomplished with wirebonds. Wirebonds in power devices and modules are prone to resistance, noise, parasitic oscillations, fatigue and eventual failure. Furthermore, there has been an increase demand for higher power density and better efficiency for power converters. Power semiconductor suppliers have been concentrating on improving device structure, density, and process technology to lower the on-resistance of MOSFETs and voltage drop of IGBTs. Recent advances made in power semiconductor technology are pushing packaging technology to the limits for performance of these power systems since the resistance and parasitics contribution by the package and the wirebonds are roughly the same as that on the silicon. In recent years, an integrated systems approach to standardizing power electronics components and packaging techniques in the form of power electronics building blocks has emerged as a new concept in the area of power electronics. As a result, it has been envisioned that the packaging of three-dimensional high-density multichip modules (MCMs) can meet the requirement for future power electronics systems. However, the conventional wirebond interconnected power devices are excluded from three-dimensional MCMs because of their large size, limited thermal management, and incompatible processing techniques. On the other hand, advanced solder joint area-array technologies, such as flip-chip technology, has emerged in microelectronics industry due to increased speed, higher packaging density, and performance, improved reliability and low cost these technologies offer. With all these benefits to offer, solder joint area-array technology has yet to be implemented for power electronics packaging. Therefore, the first objective of this study is to design and develop a solder joint area-array interconnection technique for power chips. Solder joint reliability is a major concern for area array technologies and power chip interconnection, thus the second objective of this study is to evaluate solder joint reliability, investigate the fatigue failure behavior of solder joint and improve solder joint reliability by developing a new solder bumping process for improved solder joint geometry, underfilling solder joint with encapsulant and applying flexible substrate in the assembly. The third objective is the implementation of solder joint interconnection technique in developing chip-scale power packages and a three-dimensional integrated power electronics module structure.
Solder joint area array interconnection for power chips has been designed with the considerations of parasitic resistance and inductance reduction, current handling capability, thermal management, reliability improvement and manufacturability. A new solder joint fabrication process, which is able to produce high standoff hourglass-shaped solder joint that consists of an inner cap, middle ball and outer cap, as well as the conventional solder bumping process have been successfully developed for power chips by using stencil printing. This solder bumping technology is compatible with the existing surface-mount assembly operations and potentially low cost. The fabricated solder joints have been characterized for their structure integrity, mechanical strength and electrical performances.
Solder joint reliability has been improved by optimizing solder joint geometry, underfilling flipped power chip and utilizing compliant substrate. Solder joint reliability was evaluated using accelerated temperate cycling and adhesion tests. The interfaces of the triple-stacked solder joints were examined using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) for the integrity of the joint. Acoustic microscopy imaging (nondestructive evaluation) was utilized to examine the quality of the bonded interfaces and to detect cracks and other defects before and during accelerated fatigue tests. Adhesion strength of both single bump barrel-shaped and stacked hourglass-shaped solder joints to bonding pads was characterized and analyzed. It was found that stacked hourglass-shaped solder joint have higher fracture stress than barrel-shaped solder joint. This verifies that hourglass-shaped solder joint has lower stress singularity at the interface between the solder bump and the silicon die as well as at the interface between the solder bump and substrate than barrel-shaped solder joint, especially around the corners of the interfaces. Furthermore, the adhesion strength of barrel-shaped solder joint decreases much faster than that of high standoff hourglass-shaped solder joint under temperature cycling, which indicates that the latter has high reliability than the former. Our accelerated temperature cycling test clearly shows that solder joint fatigue failure process consists of three phases: crack initiation, crack propagation and catastrophic failure. Solder joint geometry, underfilling and substrate flexibility were proved to affect solder joint reliability. The effects of solder joint shape and standoff height on reliability have been systematically studied experimentally for the first time. Our experimental results indicated that both hourglass shape and great standoff height could improve solder joint fatigue lifetime, with standoff height being the more effective factor. The fatigue lifetime of high standoff hourglass-shaped solder joint is improved mainly by prolonged crack propagation time, with slight improvement in crack initiation time. Experimental data suggested that shape is the dominant factor affecting crack initiation time while standoff height is the major factor influencing crack propagation time. Underfilling and flexible substrate improved the lifetime of both barrel and hourglass-shaped solder joints. The effect of underfill on solder joint reliability is well known in microelectronics packaging field. However, for the first time, it is reported in this study that flex substrate could improve solder joint reliability. It has been found that flex substrate bucks during temperature cycling and thus reduces thermal strain in solder joints, which in turn improves solder joint fatigue lifetime.
Chip scale packaging can enable a few very important concepts and advantages in power electronics packaging. It offers high silicon to package footprint ratio, provides a known good die solution to power chips, improves electrical as well as thermal performance and creates an opportunity for power component standardization. Two kinds of chip-scale power packages have been developed in this research. One is called cavity down flip chip on flex; the other is termed Die Dimensional Ball Grid Array (D2BGA). Both utilize solder joint as chip-level interconnection. Electrical tests show that the VCE(sat) of the high speed IGBT chip-scale packages is improved by 20% to 30% by eliminating the device¡¯s wirebonds and other external interconnections, such as leadframe. Double-sided cooling is realized in these CSPs. Temperature cycling test shows that the CSPs are reliable.
Integrated power electronics modules (IPEMs) are envisioned as integrated power modules consisting of power semiconductor devices, power integrated circuits, sensors, and protection circuits for a wide range of power electronics applications, such as inverters for motor drives and converters for power processing equipment. We have developed a three-dimensional approach, termed flip chip on flex (FCOF), for packaging high-performance IPEMs. The new concept is based on the use of solder joint (D2BGA chip scale package), not bonding wires, to interconnect power devices. This packaging approach has the potential to produce modules having superior electrical and thermal performance and improved reliability. We have demonstrated the feasibility of this approach by constructing half-bridge converters (consisting of two IGBTs, two power diodes, and a simple gate driver circuitry) which have been successfully tested at power levels over 30 kW. Switching tests have shown that parasitic inductance of the FCOF module has been reduced by 40% to 50% over conventional wire bond power modules. Better thermal management can be achieved in this three-dimensional power module structure. Compared with the state-of-the-art half-bridge power modules, the volume of the half-bridge FCOF power module is reduced by at least 65%. Reliability test shows that this flip chip on flex power module structure is potentially more reliable than wire bond power module.Ph. D.
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Tervo, V. (Valtteri). "Joint multiuser power allocation and iterative multi-antenna receiver design." Doctoral thesis, Oulun yliopisto, 2015. http://urn.fi/urn:isbn:9789526207292.
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Abstract This thesis concentrates on joint optimization of transmit power allocation and receive filtering in multiuser, multi-antenna communications. Due to the increasing number of wireless devices, the design of energy-efficient communication links is becoming increasingly important. In cellular mobile communications, reducing the average power consumption in uplink transmission is beneficial for users in order to extend battery life and, hence, energy efficiency in general. However, the power consumption of the high power amplifier (HPA) at the transmitter depends on the peak power of the transmission. This thesis focuses on power allocation problems for single-carrier (SC) frequency division multiple access (FDMA) and orthogonal FDMA (OFDMA) transmission assuming iterative reception. The goal in the first scheme presented in this thesis is to reduce the average power consumption by designing a power allocation method that takes into account the convergence properties of an iterative receiver in multiuser uplink communications. The proposed scheme can guarantee that the desired quality of service (QoS) is achieved after a sufficient number of iterations. Reducing the peak-to-average power ratio (PAPR) in any transmission system is beneficial because it allows the use of inexpensive, energy-efficient power amplifiers. The goal in the second scheme presented in this thesis is to control the PAPR of the transmitted signal. Hence, in addition to the QoS constraint, the instantaneous PAPR constraint is derived for SC-FDMA and OFDMA transmission. Moreover, a statistical approach is considered in which the power variance of the transmitted waveform is controlled. The QoS and PAPR constraints are considered jointly and, therefore, the proposed power allocation strategy jointly takes into account the channel quality and the PAPR characteristics of the power amplifier. However, the PAPR constraint can be adopted to any SC-FDMA or OFDMA framework and it is not restricted to the scheme presented in this thesis. The objective of the optimization problems considered throughout the thesis is to minimize the sum power. The majority of the derived constraints are non-convex and therefore, two alternative successive convex approximations (SCAs) are derived for all the non-convex constraints considered. The numerical results show that the proposed power allocation strategies can significantly reduce the average transmission power of users while allowing flexible PAPR control. Hence, the proposed methods can be used to extend battery life for users and especially improve the QoS at the cell edgesTiivistelmä Väitöskirjassa tutkitaan lähettimessä tapahtuvan tehoallokoinnin sekä vastaanottimessa tapahtuvan signaalin suodatuksen yhteisoptimointia monikäyttöön suunnatussa langattomassa moniantennikommunikaatiossa. Langattomien laitteiden lukumäärän kasvaessa energiatehokkuuden merkitys tiedonsiirtolinkkien suunnittelussa korostuu. Soluihin perustuvassa langattomassa tietoliikenteessä keskimääräisen tehonkulutuksen pienentäminen ylälinkkilähetyksessä (käyttäjältä tukiasemaan) on tärkeää käyttäjän kannalta, sillä se pidentää laitteen akun kestoa. Lähettimen tehovahvistimen (high power amplifier (HPA)) tehonkulutus on kuitenkin verrannollinen lähetyksen huipputehoon. Väitöskirjassa luodaaan uusia menetelmiä sekä vertaillaan tehoallokointia yhden kantoaallon taajuustason monikäyttöön (single carrier frequency division multiple access (SC-FDMA)) ja ortogonaalisen taajuustason monikäyttöön (orthogonal FDMA (OFDMA)) perustuvissa lähetysteknologioissa. Työn ensimmäisessä osiossa tavoitteena on keskimääräisen tehonkulutuksen pienentäminen monen käyttäjän ylälinkkikommunikaatiossa suunnittelemalla tehoallokointimenetelmä, joka ottaa huomioon iteratiivisen vastaanottimen konvergenssiominaisuudet. Työssä ehdotettu menetelmä takaa vastaanotetun informaation halutun laadun (quality of service (QoS)) riittävän monen vastaanottimessa tehdyn iteraation jälkeen. Huipputehon ja keskitehon suhteen (peak to average power ratio (PAPR)) pienentäminen missä tahansa lähetyksessä on hyödyllistä, sillä sen ansiosta voidaan käyttää energiatehokkaampia ja halvempia tehovahvistimia. Työn jälkimmäisessä osiossa tavoitteena on kontrolloida lähetetyn signaalin huipputehon ja keskitehon suhdetta. Työn ensimmäisessä osiossa esitetyn QoS-rajoitteen lisäksi tehoallokointia rajoitetaan symbolisekvenssikohtaisella PAPR-rajoitteella SCFDMA- ja OFDMA-lähetyksessä. Lisäksi esitetään tilastollinen menetelmä, jossa rajoitetaan lähetetyn signaalin tehon varianssia. Kun käytetään yhtäaikaisesti QoS- ja PAPR-rajoitteita, voidaan tiedonsiirtokanavaan suunnitella optimaalinen tehoallokointi ottaen huomioon tehovahvistimen epälineaarisuudet. Työssä esitetty PAPR-rajoite on kuitenkin geneerinen, ja se voidaan sovittaa mihin tahansa SCFDMA- tai OFDMA- optimointikehykseen. Työssä esitettävien optimointiongelmien tavoitteena on käyttäjien summatehon minimointi. Suurin osa työssä esiintyvistä ongelmista on ei-konvekseja, joten siinä esitetään kaksi vaihtoehtoista peräkkäinen konveksi approksimaatio (successive convex approximation (SCA)) -menetelmää kaikille ei-konvekseille rajoitteille. Numeeriset tulokset osoittavat, että esitetyt tehoallokointimenetelmät pienentävät merkittävästi keskimääräistä tehonkulutusta mahdollistaen lisäksi adaptiivisen PAPR-kontrolloinnin. Väitöskirjassa esitettyjen menetelmien avulla voidaan pidentää mobiilikäyttäjien akun kestoa sekä erityisesti parantaa solun reunakäyttäjien palvelun laatua
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Hamilton, Stephanie E. "The influence of passive ankle joint power on balance recovery." Thesis, Michigan Technological University, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3724620.
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Over one–third of Americans over the age of 65 fall each year, costing more than $19 billion in health care costs in 2000. Many adults 65+ who have not experienced a fall still fear falling, and fear can decrease quality of life and increase the likelihood of falls. Several factors such as muscle strength, power, stiffness and tendon properties change in the human body with age affecting balance, which has been tagged as a fall risk predictor. Additionally, balance recovery strategies also differ between young and older adults, with young adults primarily utilizing their ankle joint and older adults utilizing their hip. The role of passive ankle joint power in balance recovery is unknown. Therefore, we conducted three studies. In Study 1, we investigated the role of passive ankle joint power in balance recovery of young subjects and tested if the contribution of passive power to net ankle joint power changed with perturbation speed. In Study 2, we explored the factor of age in the contribution of passive ankle joint power to net ankle joint power. In Study 3, we searched for a link between the contribution of passive ankle joint power to net ankle joint power and balance recovery strategy. Passive joint torque through the full range of motion was collected for each subject. Each subject performed 5 stepping tasks at two speeds, fast and slow. Joint kinematics and kinetics were collected for each trial. Inverse dynamics were performed and net ankle joint torque and net ankle joint work were computed. Passive ankle joint torque models were optimized for each subject, and passive ankle joint powers were determined. In Study 1, there appeared to be no difference in net or passive joint powers with respect to perturbation speed. In Study 2, age affected net ankle joint powers and passive uniarticular plantar- and dorsiflexor powers. In Study 3, we noted a change in balance recovery strategy between young and older adults. We were unable to predict balance recovery strategy index based off of the percent contribution of passive ankle joint work to net ankle joint work. These studies bring greater clarity to the role of passive ankle joint power with respect to balance recovery.
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PERCIA, GUILHERME ZENKNER. "JOINT POWER CONTROL AND CHANNEL ALOCATIN IN CELLULAR WIRELESS SYSTEMS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1997. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=8630@1.
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOEste trabalho investiga o comportamento de três métodos de alocação de canais para Sistemas Móveis Celulares quando associados a três algoritmos de controle de potência distribuídos. Os objetivos desta associação são uma maior capacidade comparada à obtida com a aplicação isolada de alocação de canais, e uma melhor distribuição da Razão Sina- Interferência, através do uso otimizado da potência de transmissão. Resultados de simulações mostram que estes dois objetivos podem ser atingidos, mas com alguns custos.
This work investigates the behavior if three channel allocation schemes for Mobile Cellular Systems, when associated to three different automatic uplink power control schemes. The two objectives sought with this association are improved capacity over the isoladed use of the allocation schemes, and a better distribuition of the Signal to Interference Ratio (SRI) due to an optimized use of transmission power. Simulation results show that indeed this can be achieved, but not without some costs.
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Moety, Farah. "Joint minimization of power and delay in wireless access networks." Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S108/document.
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Dans les réseaux d'accès sans fil, l'un des défis les plus récents est la réduction de la consommation d'énergie du réseau, tout en préservant la qualité de service perçue par les utilisateurs finaux. Cette thèse propose des solutions à ce problème difficile considérant deux objectifs, l'économie d'énergie et la minimisation du délai de transmission. Comme ces objectifs sont contradictoires, un compromis devient inévitable. Par conséquent, nous formulons un problème d’optimisation multi-objectif dont le but est la minimisation conjointe de la puissance consommée et du délai de transmission dans les réseaux sans-fil. La minimisation de la puissance est réalisée en ajustant le mode de fonctionnement des stations de base (BS) du réseau d’un niveau élevé de puissance d’émission vers un niveau d'émission plus faible ou même en mode veille. La minimisation du délai de transmission est réalisée par le meilleur rattachement des utilisateurs avec les BS du réseau. Nous couvrons deux réseaux sans-fil différents en raison de leur pertinence : les réseaux locaux sans-fil (IEEE 802.11 WLAN) et les réseaux cellulaires dotés de la technologie LTEIn wireless access networks, one of the most recent challenges is reducing the power consumption of the network, while preserving the quality of service perceived by the end users. The present thesis provides solutions to this challenging problem considering two objectives, namely, saving power and minimizing the transmission delay. Since these objectives are conflicting, a tradeoff becomes inevitable. Therefore, we formulate a multi-objective optimization problem with aims of minimizing the network power consumption and transmission delay. Power saving is achieved by adjusting the operation mode of the network Base Stations (BSs) from high transmit power levels to low transmit levels or even sleep mode. Minimizing the transmission delay is achieved by selecting the best user association with the network BSs. We cover two different wireless networks, namely IEEE 802.11 wireless local area networks and LTE cellular networks
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Sanchez, Lynda M. "Using the Power of 3 with Total Joint Surgery Patients." ScholarWorks, 2016. https://scholarworks.waldenu.edu/dissertations/2057.
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The purpose of patient education is to provide patients and their families with the tools needed to care for themselves after discharge from the hospital, but shortened hospital stays, limited health literacy, language, and age can impede the patient's comprehension of the information provided. Researchers have found that the lack of effective patient education is related to 30-day hospital readmissions. The Power of 3 educational tool, designed by Sanchez and Cooknell, addressed the factors that impeded effective patient teaching by using the adult learning theory and low health literacy concepts. The Power of 3 was implemented as a quality improvement project in the Total Joint Center in October 2014. The purpose of this project was to assess the effect of an adult learning-based educational tool on the readmission rates for venous thrombus embolism and infection and on the effect on mobility in total joint surgery patients. This goal was accomplished by performing a retrospective chart review on 90 randomized patients, 45 before and 45 after implementation. The Power of 3 demonstrated a statistically significant change in the length of time a patient remained out of bed on the day of surgery after implementing the educational tool (0.75 hours vs. 1.514 hours, p = 0.0182, CI 95%). In addition, the number of patients that nursing staff documented who were out of bed was also statistically significant on the day of surgery (12 patients vs. 24, p = 0.0461, CI 95%). This educational tool can facilitate patient teaching by addressing language and educational barriers between patients and health care workers.
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Abdul, Aziz Hasan Ali Aamir, and Muhammad Adil Shahzad. "A Joint Subcarrier/Power allocation Scheme for OFDMA-based Cellular Networks." Thesis, Linköpings universitet, Kommunikations- och transportsystem, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-91310.
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The assignment of this master thesis consists of initiating power, subcarrier allocation in a dynamic FFR based scheme designed for multi-cell OFDMA networks and to enhance the throughput of all center users in bandwidth hungry borrower cells (overloaded cells) which was previously degraded by original FFR3 scheme as a result of partitioning of system bandwidth into center and edge bands respectively. The method uses band borrowing to compensate center user’s throughput loss in a semi and fully overloaded system. The scheme uses dynamic programming method (0/1 knapsack problem) to bargain an edge band on various power levels and tends to check the best combination (power and sub-carrier) which the system can utilize while still maintaining acceptable throughput loss for the users at the edge of the neighboring cell (lender cell). The algorithm consists of generating a borrowing request to neighboring cells for utilizing their edge bands by the overloaded borrower cell if their average center user throughput reaches below a minimum threshold value set in the system. The borrowing method uses 0/1 knapsack problem to capture an edge band based on limiting factors of total cost in average throughput losses by neighbors (Ci) and Un (tolerable mean user edge user throughput loss by lending cell). While solving knapsack problem the lender (neighbors) will check Ci and Un before granting the right to use its edge band. The later stage requires reducing subcarrier power level in order to utilize the lenders edge band using "soft borrower" mode. The borrowed sub-carriers will be activated take power from the original center band sub-carriers of the overloaded cell by taking into account the interference between the lender and the borrower. In case of negative (0) reply from the lender cell after the first request, multiple requests are generated at reduce power level at every step to order to acquire more bands. If a neighbor has band borrowing requests from multiple overloaded base stations, the band will be granted to the one which gives minimal loss in terms of throughput to the lender cell. The simulation results are analyzed w.r.t reuse-1 and FFR3 scheme of a multi cell regular and irregular scenarios comprising of lightly to heavily overloaded cells with various subcarrier allocation patterns. An overhead and time assessment is also presented between borrower and lender cells. Simulation results show an increase of 60% in center user’s throughput w.r.t original FFR3 scheme with an acceptable loss of 18% at the edges in complex overloaded scenarios while the overall system throughout increases by 35%.
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Yang, Min Li. "Bargaining power, ownership and control of international joint ventures in Taiwan." Thesis, University of Glasgow, 2006. http://theses.gla.ac.uk/1443/.
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This thesis provides an empirical analysis of international joint venture activities in Taiwan. The primary purpose is to examine control and its antecedents in terms of ownership, bargaining power, resources contribution, and motivation for forming international joint ventures. Primary data collected by a mail questionnaire is analysed along five core dimensions of international joint venture activities. First, the mechanism, focus, and extent of parent control is identified and tested in a number of sample characteristics. These empirical results also reveal that most joint ventures in Taiwan have higher autonomy and have more autonomy on the appointment of key function managers. Parent firms seek to focus their control over specific activities of the joint ventures rather than attempting to control the entire range of joint venture activities. Second, the results of equity shares held by the host country parents and foreign parents show that both parents have minority shareholding in the joint ventures. A higher ownership by the parents in joint ventures indicates that they have a higher percentage of board members. Third, the relative importance of a set of bargaining power is identified with hypothesis testing of the relationship between control and bargaining power. There is little evidence that the relationship between bargaining power and control is not closely associated. Fourth, the relative importance of resource contribution by parents is identified and hypotheses are tested on the relationship between control and resource contribution factors. The results are strongly supported that the relationships between resource contributions in terms of physical, invisible, financial, human, and organizational ability of parents and their control has significant and positive associations. Fifth, the relative importance of a set of motives for international joint venture formation is identified and hypotheses are tested on the relationship between control and motivation factors in terms of technological acquisition, knowledge learning, risk sharing, competitive strategy consideration, resource complementarily, market expansion. The findings reveal a limited number of significant correlations between motivation factors and control.
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Simões, Carla Costa. "A joint venture contratual e o direito concorrencial." Universidade Presbiteriana Mackenzie, 2012. http://tede.mackenzie.br/jspui/handle/tede/1066.
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Previous issue date: 2012-09-04The contractual joint venture comes from an association of interests synthesized in a contract, which will determine all wills and goals of co-venturers. The connection between contractual joint venture and competition law occurs when a non corporate joint venture s creation, being a contractual legal instrument as is, can be adjusted by the parties as best fit them. Such a contractual association may aim to infringe freedom of competition, which affects the economic power, and, as a result of the relationship merely contractual, it is difficult for the State to monitor this conduct.
A joint venture contratual advém de uma associação de interesses sintetizada em um contrato, que determinará todas as vontades e objetivos dos coventurers. A ligação do instituto da joint venture contratual com o direito da concorrência ocorre na medida em que a criação de uma non corporate joint venture, sendo um instrumento jurídico contratual como é, pode ser ajustada pelas partes como melhor lhes aprouverem. Tal associação contratual poderá ter como objetivo infringir a livre concorrência, o que afeta o Poder Econômico, e, em razão da relação meramente contratual, é difícil para o Estado fiscalizar este tipo de conduta.
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Fallgren, Mikael. "Optimization of Joint Cell, Channel and Power Allocation in Wireless Communication Networks." Doctoral thesis, KTH, Optimeringslära och systemteori, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-40274.
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In this thesis we formulate joint cell, channel and power allocation problems within wireless communication networks. The objectives are to maximize the user with mini- mum data throughput (Shannon capacity) or to maximize the total system throughput, referred to as the max-min and max-sum problem respectively. The complexity is stud- ied together with proposed optimization- and heuristic-based approaches. In the first paper an overall joint cell, channel and power allocation max-min prob- lem is formulated. We show that the decision problem is NP-hard and that the op- timization problem is not approximable unless P is equal to NP, for instances with a sufficiently large number of channels. Further, it follows that for a feasible binary cell and channel allocation, the remaining continuous power allocation optimization problem is still not approximable unless P is equal to NP. In addition, it is shown that first-order optimality conditions give global optimum of the single channel power al- location optimization problem, although the problem is in general not convex. In the following two papers heuristics for solving the overall problem are proposed. In the second paper we consider the single channel problem with convex combinations of the max-min and the max-sum objective functions. This variable utility provides the ability of tuning the amount of fairness and total throughput. The third paper investi- gates the multiple channel setting. On a system with three cells, eight mobile users and three channels, we perform an exhaustive search over feasible cell and channel alloca- tions. The exhaustive search is then compared to the less computationally expensive heuristic approaches, presenting potential earnings to strive for. A conclusion is that several of the proposed heuristics perform very well. The final paper incorporates fixed relay stations into the overall joint cell, channel and power allocation max-min problem. The complexity is inherited from the formula- tion without relay stations. Further, we propose a heuristic channel allocation approach that shows good performance, compared to an optimization based approach, in numer- ical simulations on the relay setting.Financial support by the Swedish Foundation for Strategic Research (SSF) QC 20110915
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Wei, Junyi. "QoS-aware joint power and subchannel allocation algorithms for wireless network virtualization." Thesis, University of Essex, 2017. http://repository.essex.ac.uk/20142/.
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Wireless network virtualization (WNV) is a promising technology which aims to overcome the network redundancy problems of the current Internet. WNV involves abstraction and sharing of resources among different parties. It has been considered as a long term solution for the future Internet due to its flexibility and feasibility. WNV separates the traditional Internet service provider’s role into the infrastructure provider (InP) and service provider (SP). The InP owns all physical resources while SPs borrow such resources to create their own virtual networks in order to provide services to end users. Because the radio resources is finite, it is sensible to introduce WNV to improve resources efficiency. This thesis proposes three resource allocation algorithms on an orthogonal frequency division multiple access (OFDMA)-based WNV transmission system aiming to improve resources utility. The subject of the first algorithm is to maximize the InP and virtual network operators’ (VNOs’) total throughput by means of subchannel allocation. The second one is a power allocation algorithm which aims to improve VNO’s energy efficiency. In addition, this algorithm also balances the competition across VNOs. Finally, a joint power and subchannel allocation algorithm is proposed. This algorithm tries to find out the overall transmission rate. Moreover, all the above alogorithms consider the InP’s quality of service (QoS) requirement in terms of data rate. The evaluation results indicates that the joint resource allocation algorithm has a better performance than others. Furthermore, the results also can be a guideline for WNV performance guarantees.
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Wang, Yun. "Characterization and reliability of Ag nanoparticle sintered joint for power electronics modules." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/37296/.
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Nowadays, numerous power electronics application requires operation at high temperatures. In order to address increasing change of reliability problems in power die attachments for high temperature and high reliability applications, sintering Ag nanoparticles has been used as bonding material for this work. Firstly, quantitative microstructure characterization of as-sintered Ag joints has been carried out. The resulting normalized thickness, pore size and porosity decreased, and grain size increased with increasing the sintering time. A time dependence of the form t1/n with n close to 2 or 3 can be further derived for the kinetics of the thinning, densification and grain growth within the sintered Ag joints. From the results can be seen, sintering kinetics is still in the intermediate stage, the densification had not been completed, and Ag grain would continue growing afterwards, which could further explain degradation behaviours of sintered joints during isothermal ageing tests and thermal cycling tests. Secondly, sintered Ag joints with four kinds of substrate metallization have been subjected to isothermal ageing tests at temperatures of 150°C, 200°C and 250°C for up to 32 days. The different microstructure patterns of sintered joints with four substrate finishes during isothermal ageing tests have been presented and compared, which could use the results to explain part of the degradation behaviours of the sintered Ag joints during thermal cycling tests and guide selection of suitable substrate finish for the die attachments in high temperature power electronic system. Furthermore, thermal cycling tests have been carried out to investigate the reliability of two sizes of sintered Ag joints and solder joints during temperature cycling between -55°C to 125°C and -55°C to 150°C. Microstructure evolution of sintered Ag joints was investigated by non-destructive and destructive characterization methods, which revealed the factors which could effect on the degradation during thermal cycling tests. With microstructure features of sintered joints observed from X-ray tomography and SAM, because a specific specimen can be evaluated over its lifetime, a true image of microstructure evolution of damage during operation can be obtained, and crack and degradation can be observed three-dimensionally.
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Shehata, S. A. M. "Analysis of stresses in the cross channel HVDC link transition joint." Thesis, University of Southampton, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356531.
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Munro, Lynne. "Assessment of joint kinetics in elite sprint cyclists." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2018. https://ro.ecu.edu.au/theses/2128.
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Sprint cycling requires the production of explosive muscle power outputs up to very high pedalling rates. The ability to assess muscular function through the course of the sprint would aid training practices for high-level performers. Inverse dynamics provides a non-invasive means of estimating the net muscle actions acting across any joint contributing to movement. However, analysis of joint kinetics requires motion-capture techniques that present some unique challenges for cycling. This thesis presents three studies investigating the application of a custom-designed force pedal system to examine the joint kinetics of elite trained track sprint cyclists. To provide the basis for selecting appropriate testing procedures, study one evaluated differences between two- and three- dimensional techniques while assessing joint kinetics of seated and standing sprint cycling at optimal cadence (the cadence where peak power is delivered). Study two examined the impact of cadence and seating position on joint kinetics, while determining testing reliability using the three-dimensional process. Coefficients of variation were established for between- and within- days repetitions of sprint performance at optimal cadence, and cadences 30% lower and 30% higher, in both seated and standing positions. Study three compared joint kinetics of sprint cycling performance with commonly-applied resistance-training exercises in an elite cycling cohort, in order to better understand training specificity. Joint-specific torque-angular velocity relationships were established from seated and standing sprinting at three cadences and the clean exercise at three loads, with other strength-based exercises examined at maximal load only.
Study one determined that flattened projections of the 3D motion into 2D resulted in significant differences in joint powers calculated in the sagittal-plane. When using 2D methods, knee joint power was significantly lower and hip transfer power significantly greater, while hip range of motion was lower and the angle where hip peak power occurred later in the crank cycle. These results indicate that 3D processes should be used where evaluation of absolute values are important, although 2D processes may still be acceptable where relative differences are being assessed. It was observed in Study two that, while crank and total muscle power upheld a quadratic power-cadence relationship, joint-specific powers were uniquely related to cadence and riding position. Crank and joint-specific optimal cadences for power production were distinctly different. The hip displayed a linear maximum power-cadence relationship in seated but quadratic in standing position, with the reverse observed at the knee. Ankle and hip transfer powers both linearly declined with cadence irrespective riding position. In such a case, joint-specific power contribution, hence distribution of muscular effort, cannot be directly inferred from power assessed at the crank. Reliability was highest for crank and total muscle power, particularly at the riders’ optimal cadence. Reliability of joint powers were somewhat lower and uniquely dependent on joint, joint action and trial condition. Results indicate that external power output at the crank is relatively stable across sprints, despite variation in the underlying muscular contributions. Results of study three showed equivalence in the torque-angular velocity relationships at the hip in sprint cycling and different phases of the clean. No such relationship was evident at the knee or ankle. In contrast to the negative linear relationships observed in all other conditions, ankle mechanics in sprinting showed a positive linear relationship highlighting a distinct functional role of this joint. Highest maximal torques at the hip and knee were observed during unilateral single rack pull and step-up exercises, respectively, supporting their efficacy for improving the maximum strength characteristics at these joints.
The results of this thesis indicate that joint kinetics are an effective means of assessing muscular performance in highly-trained track sprint cyclists and provide information on the underlying strategies that could not be assessed through conventional testing of power at the crank. The use of 3D processes is recommended where accuracy of assessment and absolute values are important. Flexibility of 2D processes may be advantageous in field-based settings and may be acceptable where only relative change is of interest. High reliability of 3D testing supports its use in monitoring of athletes, with the reliability data presented in this thesis providing an indication of the smallest meaningful changes in various trial conditions. Low coefficients of variation observed in crank and muscle power terms, despite greater variation in joint powers, suggest motor control strategies dynamically respond to task conditions while maintaining a consistent external power. Resistance exercises are seen to display jointspecific profiles that characterise relative hip- or knee- dominance. The comparison of these profiles with those of sprint cycling can help inform exercise selection for strength development of elite riders. The ability to monitor changes and target training intervention at joint level provides a unique approach to athlete development. Outcomes of this thesis support the practical application of joint kinetic assessment in aiding training practices to the highest levels of competition in track sprint cycling. Indeed, the equipment, methods and knowledge obtained from this research is currently applied in the preparation of Australia’s best sprint cyclists.
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Alam, Md Zahangir. "Joint transceiver design and power optimization for wireless sensor networks in underground mines." Master's thesis, Université Laval, 2018. http://hdl.handle.net/20.500.11794/30663.
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Avec les grands développements des technologies de communication sans fil, les réseaux de capteurs sans fil (WSN) ont attiré beaucoup d’attention dans le monde entier au cours de la dernière décennie. Les réseaux de capteurs sans fil sont maintenant utilisés pour a surveillance sanitaire, la gestion des catastrophes, la défense, les télécommunications, etc. De tels réseaux sont utilisés dans de nombreuses applications industrielles et commerciales comme la surveillance des processus industriels et de l’environnement, etc. Un réseau WSN est une collection de transducteurs spécialisés connus sous le nom de noeuds de capteurs avec une liaison de communication distribuée de manière aléatoire dans tous les emplacements pour surveiller les paramètres. Chaque noeud de capteur est équipé d’un transducteur, d’un processeur de signal, d’une unité d’alimentation et d’un émetteur-récepteur. Les WSN sont maintenant largement utilisés dans l’industrie minière souterraine pour surveiller certains paramètres environnementaux, comme la quantité de gaz, d’eau, la température, l’humidité, le niveau d’oxygène, de poussière, etc. Dans le cas de la surveillance de l’environnement, un WSN peut être remplacé de manière équivalente par un réseau à relais à entrées et sorties multiples (MIMO). Les réseaux de relais multisauts ont attiré un intérêt de recherche important ces derniers temps grâce à leur capacité à augmenter la portée de la couverture. La liaison de communication réseau d’une source vers une destination est mise en oeuvre en utilisant un schéma d’amplification/transmission (AF) ou de décodage/transfert (DF). Le relais AF reçoit des informations du relais précédent et amplifie simplement le signal reçu, puis il le transmet au relais suivant. D’autre part, le relais DF décode d’abord le signal reçu, puis il le transmet au relais suivant au deuxième étage s’il peut parfaitement décoder le signal entrant. En raison de la simplicité analytique, dans cette thèse, nous considérons le schéma de relais AF et les résultats de ce travail peuvent également être développés pour le relais DF. La conception d’un émetteur/récepteur pour le relais MIMO multisauts est très difficile. Car à l’étape de relais L, il y a 2L canaux possibles. Donc, pour un réseau à grande échelle, il n’est pas économique d’envoyer un signal par tous les liens possibles. Au lieu de cela, nous pouvons trouver le meilleur chemin de la source à la destination qui donne le rapport signal sur bruit (SNR) de bout en bout le plus élevé. Nous pouvons minimiser la fonction objectif d’erreur quadratique moyenne (MSE) ou de taux d’erreur binaire (BER) en envoyant le signal utilisant le chemin sélectionné. L’ensemble de relais dans le chemin reste actif et le reste des relais s’éteint, ce qui permet d’économiser de l’énergie afin d’améliorer la durée de vie du réseau. Le meilleur chemin de transmission de signal a été étudié dans la littérature pour un relais MIMO à deux bonds mais est plus complexe pour un ...With the great developments in wireless communication technologies, Wireless Sensor Networks (WSNs) have gained attention worldwide in the past decade and are now being used in health monitoring, disaster management, defense, telecommunications, etc. Such networks are used in many industrial and consumer applications such as industrial process and environment monitoring, among others. A WSN network is a collection of specialized transducers known as sensor nodes with a communication link distributed randomly in any locations to monitor environmental parameters such as water level, and temperature. Each sensor node is equipped with a transducer, a signal processor, a power unit, and a transceiver. WSNs are now being widely used in the underground mining industry to monitor environmental parameters, including the amount of gas, water, temperature, humidity, oxygen level, dust, etc. The WSN for environment monitoring can be equivalently replaced by a multiple-input multiple-output (MIMO) relay network. Multi-hop relay networks have attracted significant research interest in recent years for their capability in increasing the coverage range. The network communication link from a source to a destination is implemented using the amplify-and-forward (AF) or decode-and-forward (DF) schemes. The AF relay receives information from the previous relay and simply amplifies the received signal and then forwards it to the next relay. On the other hand, the DF relay first decodes the received signal and then forwards it to the next relay in the second stage if it can perfectly decode the incoming signal. For analytical simplicity, in this thesis, we consider the AF relaying scheme and the results of this work can also be developed for the DF relay. The transceiver design for multi-hop MIMO relay is very challenging. This is because at the L-th relay stage, there are 2L possible channels. So, for a large scale network, it is not economical to send the signal through all possible links. Instead, we can find the best path from source-to-destination that gives the highest end-to-end signal-to-noise ratio (SNR). We can minimize the mean square error (MSE) or bit error rate (BER) objective function by sending the signal using the selected path. The set of relay in the path remains active and the rest of the relays are turned off which can save power to enhance network life-time. The best path signal transmission has been carried out in the literature for 2-hop MIMO relay and for multiple relaying it becomes very complex. In the first part of this thesis, we propose an optimal best path finding algorithm at perfect channel state information (CSI). We consider a parallel multi-hop multiple-input multiple-output (MIMO) AF relay system where a linear minimum mean-squared error (MMSE) receiver is used at the destination. We simplify the parallel network into equivalent series multi-hop MIMO relay link using best relaying, where the best relay ...
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Chen, Renjie. "Using PPP deviations as a trading rule : an indirect joint test of PPP and foreign exchange market efficiency." Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/42010.
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In this thesis an international investment filter rule is used to test both the tendency for
Purchasing Power Parity (PPP) to hold in the long run and the hypothesis of foreign
exchange market efficiency for the four most actively traded currencies in the world
vis-a-vis the United States dollar: the British pound, the Japanese yen, the Germany
mark, and the Canadian dollar. One way to examine whether there is a tendency for
PPP to hold in the long run and whether the foreign exchange market is efficient, is to
place more money in the 'undervalued' currency according to PPP deviations or to invest
according to PPP deviations, putting more money into interest bearing securities in the
'undervalued' currency, the more this currency is undervalued. The return can then be
compared with a reference rule which does not use this filter, but instead puts an equal
value of money into the currencies or the securities of each country.
This thesis has produced three results. First, using the PPP filter in the exchange
money market yields no significantly abnormal rate of return compared with the reference
rule. The result suggests that we can not reject the hypothesis that the tendency for PPP
to hold in the long run does not exist. Second, using the PPP filter to invest in securities
also yields no significantly higher rate of return compared with the reference rule. And
third, when comparing the domestic (or foreign) interest rates with the rates of return
for the domestic (or foreign) investor who uses the PPP filter, there is no significant
difference between these rates in the long run. The last two results suggest that we can
not reject the hypothesis that the foreign exchange-market is efficient.Business, Sauder School of
Graduate
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Murray, Amanda Megan. "The Effects of High-Velocity Power Training on Knee Joint Mechanics in Knee Osteoarthritis." University of Toledo / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1404391903.
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Steinel, Anna. "Power, structures, and norms." Doctoral thesis, Humboldt-Universität zu Berlin, Philosophische Fakultät III, 2007. http://dx.doi.org/10.18452/15706.
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Die vorliegende Arbeit beschäftigt sich mit der Untersuchung der institutionalisierten Beziehungen zwischen der NATO und Russland seit 1997 und konzentriert sich dabei besonders auf die Ergebnisse des „Permanent Council“ (PJC, 1997) und des „NATO-Russia Council“ (NRC, 2002). Das Vermächtnis von Strukturen, die während des kalten Krieges entstanden, beeinflusst weiterhin die Interaktionen zwischen der NATO und Russland. Dies wurde insbesondere während der Kosovo-Krise und nach dem 11. September 2001, welcher die „post-post-Cold War era“ einläutete, sichtbar. Das zentrale Kapitel der Dissertation beinhaltet eine empirische Analyse der Policy-Felder, denen sich der PJC und der NRC widmen. Hier wird vor allem auf die Zusammenarbeit von der NATO und Russland auf dem Balkan und auf den Kampf gegen den Terrorismus eingegangen. Die Fallstudie untersucht NATO-Russland Interaktionen in Zentralasien; besonders im Hinblick auf geopolitische Trends, die für beide Akteure und ihre zukünftigen Beziehungen wichtige Auswirkungen haben werden. Diese Arbeit untersucht die Qualität der Beziehungen zwischen der NATO und Russland anhand von Ereignissen, welche diese Beziehungen geprägt haben und erklärt, warum manche Verhaltensmuster sich kontinuierlich wiederholen.This dissertation examines the institutionalized relationship between NATO and Russia since 1997; focussing on the outcomes of the 1997 Permanent Joint Council (PJC) and the 2002 NATO-Russia Council (NRC). The legacy of Cold War structures has continued to influence the way NATO and Russia interact; most notably during the Kosovo crisis and in the aftermath of the attacks of September 11 that rang in the “post-post-Cold War era”. The bulk of the research consists of an empirical analysis of policy fields covered by the PJC and the NRC. Particular attention is given to NATO-Russia interaction in the Balkans, as well as to the fight against terrorism. The case study assesses NATO-Russia interaction in Central Asia, taking into consideration geopolitical trends that will shape both actors’ actions in the future. Tracing events that have shaped NATO-Russia relations, this dissertation analyzes the quality of NATO-Russia relations and explains why certain patterns keep reoccurring.
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Raja, Nouman Saeed. "Combined source-channel coding for a power and bandwidth constrained noisy channel." Texas A&M University, 2003. http://hdl.handle.net/1969.1/1589.
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This thesis proposes a framework for combined source-channel coding under power and bandwidth constrained noisy channel. The framework is then applied to progressive image coding transmission using constant envelope M-ary Phase Shift Key (MPSK) signaling over an Additive White Gaussian Channel (AWGN) channel. First the framework for uncoded MPSK signaling is developed. Then, its extended to include coded modulation using Trellis Coded Modulation (TCM) for MPSK signaling. Simulation results show that coded MPSK signaling performs 3.1 to 5.2 dB better than uncoded MPSK signaling depending on the constellation size. Finally, an adaptive TCM system is presented for practical implementation of the proposed scheme, which outperforms uncoded MPSK system over all signal to noise ratio (Es/No) ranges for various MPSK modulation formats.
In the second part of this thesis, the performance of the scheme is investigated from the channel capacity point of view. Using powerful channel codes like Turbo and Low Density Parity Check (LDPC) codes, the combined source-channel coding scheme is shown to be within 1 dB of the performance limit with MPSK channel signaling.
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Mendil, Mouhcine. "Joint radio and power resource optimal management for wireless cellular networks interconnected through smart grids." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAT087/document.
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Face à l'explosion du trafic mobile entraînée par le succès des smartphones, les opérateurs de réseaux mobiles (MNOs) densifient leurs réseaux à travers le déploiement massif des stations de base à faible portée (SBS), capable d’offrir des services très haut débit et de remplir les exigences de capacité et de couverture. Cette nouvelle infrastructure, appelée réseau cellulaire hétérogène (HetNet), utilise un mix de stations de base hiérarchisées, comprenant des macro-cellule à forte puissance et des SBS à faible puissance.La prolifération des HetNets soulève une nouvelle préoccupation concernant leur consommation d'énergie et empreinte carbone. Dans ce contexte, l'utilisation de technologies de production d'énergie dans les réseaux mobiles a suscité un intérêt particulier. Les sources d'énergie respectueuses de l'environnement couplées à un système de stockage d'énergie ont le potentiel de réduire les émissions carbone ainsi que le coût opérationnel énergétique des MNOs.L'intégration des énergies renouvelables (panneau solaire) et du stockage d'énergie (batterie) dans un SBS gagne en efficacité grâce aux leviers technologiques et économiques apportés par le smart grid (SG). Cependant, l'architecture résultante, que nous appelons Green Small-Cell Base station (GSBS), est complexe. Premièrement, la multitude de sources d'énergie, le phénomène de viellissement du système et le prix dynamique de l'électricité dans le SG sont des facteurs qui nécessitent planification et gestion pour un fonctionnement plus efficace du GSBS. Deuxièmement, il existe une étroite dépendance entre le dimensionnement et le contrôle en temps réel du système, qui nécessite une approche commune capable de résoudre conjointement ces deux problèmes. Enfin, la gestion holistique d’un HetNet nécessite un schéma de contrôle à grande échelle pour optimiser simultanément les ressources énergétiques locales et la collaboration radio entre les SBSs.Par conséquent, nous avons élaboré un cadre d'optimisation pour le pré-déploiement et le post-déploiement du GSBS, afin de permettre aux MNOs de réduire conjointement leurs dépenses d'électricité et le vieillissement de leurs équipements. L'optimisation pré-déploiement consiste en un dimensionnement du GSBS qui tient compte du vieillissement de la batterie et de la stratégie de gestion des ressources énergétiques. Le problème associé est formulé et le dimensionnement optimal est approché en s'appuyant des profils moyens (production, consommation et prix de l'électricité) à travers une méthode itérative basée sur le solveur non-linéaire “fmincon”. Le schéma de post-déploiement repose sur des capacités d'apprentissage permettant d'ajuster dynamiquement la gestion énergétique du GSBS à son environnement (conditions météorologiques, charge de trafic et coût de l'électricité). La solution s'appuie sur le fuzzy Q-learning qui consiste à combiner le système d'inférence floue avec l'algorithme Q-learning. Ensuite, nous formalisons un système d'équilibrage de charge capable d'étendre la gestion énergétique locale à une collaboration à l'échelle réseau. Nous proposons à ce titre un algorithme en deux étapes, combinant des contrôleurs hiérarchiques au niveau du GSBS et au niveau du réseau. Les deux étapes s'alternent pour continuellement planifier et adapter la gestion de l'énergie à la collaboration radio dans le HetNet.Les résultats de la simulation montrent que, en considérant le vieillissement de la batterie et l'impact mutuel de la conception du système sur la stratégie énergétique (et vice-versa), le dimensionnement optimal du GSBS est capable de maximiser le retour sur investissement. En outre, grâce à ses capacités d'apprentissage, le GSBS peut être déployé de manière plug-and-play, avec la possibilité de s'auto-organiser, d'améliorer le coût énergétique du système et de préserver la durée de vie de la batteriePushed by an unprecedented increase in data traffic, Mobile Network Operators (MNOs) are densifying their networks through the deployment of Small-cell Base Stations (SBS), low-range radio-access transceivers that offer enhanced capacity and improved coverage. This new infrastructure – Heterogeneous cellular Network (HetNet) -- uses a hierarchy of high-power Macro-cell Base Stations overlaid with several low-power (SBSs).The augmenting deployment and operation of the HetNets raise a new crucial concern regarding their energy consumption and carbon footprint. In this context, the use of energy-harvesting technologies in mobile networks have gained particular interest. The environment-friendly power sources coupled with energy storage capabilities have the potential to reduce the carbon emissions as well as the electricity operating expenditures of MNOs.The integration of renewable energy (solar panel) and energy storage capability (battery) in SBSs gain in efficiency thanks to the technological and economic enablers brought by the Smart Grid (SG). However, the obtained architecture, which we call Green Small-Cell Base Station (GSBS), is complex. First, the multitude of power sources, the system aging, and the dynamic electricity price in the (SG) are factors that require design and management to enable the (GSBS) to efficiently operate. Second, there is a close dependence between the system sizing and control, which requires an approach to address these problems simultaneously. Finally, the achievement of a holistic management in a (HetNet) requires a network-level energy-aware scheme that jointly optimizes the local energy resources and radio collaboration between the SBSs.Accordingly, we have elaborated pre-deployment and post-deployment optimization frameworks for GSBSs that allow the MNOs to jointly reduce their electricity expenses and the equipment degradation. The pre-deployment optimization consists in an effective sizing of the GSBS that accounts for the battery aging and the associated management of the energy resources. The problem is formulated and the optimal sizing is approximated using average profiles, through an iterative method based on the non-linear solver “fmincon”. The post-deployment scheme relies on learning capabilities to dynamically adjust the GSBS energy management to its environment (weather conditions, traffic load, and electricity cost). The solution is based on the fuzzy Q-learning that consists in tuning a fuzzy inference system (which represents the energy arbitrage in the system) with the Q-learning algorithm. Then, we formalize an energy-aware load-balancing scheme to extend the local energy management to a network-level collaboration. We propose a two-stage algorithm to solve the formulated problem by combining hierarchical controllers at the GSBS-level and at the network-level. The two stages are alternated to continuously plan and adapt the energy management to the radio collaboration in the HetNet.Simulation results show that, by considering the battery aging and the impact of the system design and the energy strategy on each other, the optimal sizing of the GSBS is able to maximize the return on investment with respect to the technical and economic conditions of the deployment. Also, thanks to its learning capabilities, the GSBSs can be deployed in a plug-and-play fashion, with the ability to self-organize, improve the operating energy cost of the system, and preserves the battery lifespan
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Elisson, Jonas. "Conceptual Design of a Polymer Based Joint between Tether and Foundation in Tidal Energy Power Plant : Concept generation and development of a polymer based joint." Thesis, Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-78964.
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This master thesis treats the development of a new component in a tidal energy power plant. The technology that the component should be used in extracts energy from tidal an low velocity currents. This is done by that a turbine is placed on a kite which is pushed forward in the water due to the lifting force acting on the wing. A tether connects the kite with a bottom joint that is placed on a foundation at the seabed. The bottom joint used today is heavy and expensive, which was the main reason to that this thesis was initiated. In this work, the possibility of using a polymer based design for the connection between the tether and foundation was investigated. The optimal outcome of the project was that the polymer solution should provide a spring function to the power plant. A lot of conventional product development methods have been used in the project. The project was divided into five parts: planning, product specification, concept generation, concept choice and conceptual design. In order to understand what was required of the solution in terms of the spring function, a model that aimed to represent what effect a spring function would have on the power plant was developed. According to the model, a spring function in the tether direction could increase the velocity of the kite in its trajectory. The model is based on some simplifications which is assessed to need further investigation. The spring function was translated to that the component should be able to elongate as a response to the force acting in the tether direction. In the concept choice phase it was chosen to proceed with a design similar to that of a bend stiffener. It was decided that a spring function was not required of the component, though desirable. A material selection was performed and the most optimal material for a single part that should be able withstand the tension, allow rotation, and provide a spring function was concluded to be TPU(ester, aromatic, Shore 50D). In the attempt to understand what was needed to be considered if the spring function should be solved by a material response in a polymer component, relevant theory was collected. A numerical analysis in Abaqus was performed which indicated that such a solution was unreasonable. It was then decided to proceed with the development of a bend stiffener, where the tether should be connected directly to the foundation. The thesis finally concludes with a conceptual design of a bend stiffener. The most suitable material for a bend stiffener was concluded to be TPU(ether, aliphatic, Shore 60D). The initial dimensions were determined by the maximum angle and tension combination that the tether would be exposed to. A static analysis was performed in Abaqus to illustrate the function of the product. The analysis indicated that a bend stiffener could provide the required function. However, the stress in the component became high, which indicated that the bend stiffener material might fail due to the applied load. In order to fully evaluate this, it was concluded that a more accurate material model was required.
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Billi, Matteo. "Joint temperature and polarisation analyses of the lack of power anomaly in the CMB anisotropy pattern." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/16205/.
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La Radiazione Cosmica di Fondo (CMB) è la radiazione emessa nell’Universo primordiale dopo la ricombinazione di elettroni e protoni in idrogeno neutro. Le osservazioni della CMB negli ultimi 30 anni hanno fortemente contribuito alla nascita della cosmologia di precisione, e all’affermazione di un modello cosmologico standard, denonimato ΛCDM, i cui parametri sono stimati con un’incertezza dell’ordine del percento o addirittura inferiore. Ciò nonostante ci sono caratteristiche non ben comprese osservate alle grandi scali angolari della mappa in temperatura di CMB, note come anomalie. Una di queste, la mancanza di potenza rispetto a quanto previsto nel modello ΛCDM, potrebbe indicare l’esistenza di una nuova fase cosmologica antecedente all’epoca inflazionaria. Tale anomalia, osservata in modo consistente sia da WMAP che da Planck, non possiede però la significatività statistica necessaria per affermare l’esistenza di tale nuova fase. Al fine di studiare questa mancanza di potenza abbiamo utilizzato diversi estimatori statistici, che includono nell’analisi sia le mappe in temperatura che quelle in polarizzazione. Estimatori specifici ed innovativi, basati sullo spettro di potenza angolare della CMB, sono stati costruiti, testati e utilizzati su simulazioni e sui dati ottenuti dal satellite Planck nel 2015. Il confronto tra le simulazioni e i dati è stato valutato fornendo la percentuale di consistenza. Sono state inoltre fornite previsioni sulla sensibilità degli estimatori proposti quando impiegati su future osservazioni di CMB. Il miglioramento trovato può arrivare a un fattore dell’ordine 30, dimostrando che le misure future di polarizzazione della CMB potranno aiutare a trasformare una anomalia, attualmente osservata solo in temperatura, in una rilevazione di un nuovo fenomeno fisico.
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Russell, John William. "A study of axial joint behaviour in a high power ultrasonic device through transfer function synthesis." Thesis, University of Glasgow, 2015. http://theses.gla.ac.uk/6378/.
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Further development of an open loop control strategy for High Power Ultrasonic (HPU) devices requires investigation of the dynamic behaviour of its interfaces. These interfaces exist between components that are assembled through a screwed threaded axial joint. An unknown prestress permeates from this bearing surface due to the tension in the stud. It is well known that the vibration of bolted interfaces is highly nonlinear. It is assumed that the axial joint will not loosen to the extent that the entire contacting surfaces will slip. Therefore the characteristic behaviour of this interface descends from the microscopic motions, of asperities in and out of contact, as slipping occurs locally. A review of the literature suggests that this physical mechanism will contribute to second harmonics in the response of the jointed system. This complex constitutive behaviour is not amenable to dynamical modelling. Instead the Bouc-Wen (BW) model for hysteresis is adopted to capture the phenomenology. The force-displacement behaviour of the axial joint is required to identify the parameters to this model. Dynamic force behaviour of a component that is subjected to high power ultrasonic loading cannot be obtained directly through conventional measurement systems. Force estimation of a set of ultrasonic test assemblies is attempted through a hybrid analytical-experimental scheme. The test assemblies consist of a Commercial Piezoelectric Actuator (CPA) or an In-House Piezoelectric Actuator (IHPA) with a stepped ultrasonic horn attached. Stepped ultrasonic horns are produced with and without an additional axial joint that is set to three different tightnesses. These are named the Jointed Horns (JH) or the Monolithic Horn (MH) respectively. The model of an actuator with the MH attached is named the linear calibration model. This is formulated through a Distributed Transfer Function Method that describes waveguides, with discontinuous parameters, that behave according to Love Rod Theory. This is too limited to represent the behaviour of a piezoelectric rod, so the electromechanical nature of the piezoelectric actuator is not considered in detail. Instead the parameters of the model are updated based on results from Experimental Modal Analysis through the Genetic Algorithm. The force at the foremost point of the piezoelectric stack is deconvolved from the distributed parameter rod model. Stable solutions to the ill-posed inverse problem are achieved by means of the Truncated Singular Value Decomposition or Tikhonov regularisation schemes. Electrical impedance analysis of the piezoelectric actuators, with a JH attached, demonstrate that the introduction of the joint to an equivalent assembly, made with the MH attached, will significantly modify the impedance behaviour. Input forces are deconvolved from the linear calibration assembly when the output is the measured response of the IHPA with the MH attached. The response of the IHPA with the JH attached is then assumed as the output and the joint force is estimated for the input force that corresponds to the voltage that was applied for the JH test. This force will be out of phase with the true linear input force to the JH assembly. The responses of the test assemblies are measured at 2 or 3 locations through Laser Doppler Vibrometry (LDV). Simultaneous images of a portion of the ultrasonic horn are recorded through an ultra-high speed camera. Digital Image Correlation (DIC) is applied to estimate a displacement field that can be compared to a LDV measurement. Good agreement in phase is found, but there are significant errors in the amplitude. It is suggested that this is the result of projection error. The strain fields are obtained from the displacement field through bi-cubic interpolation. It is not possible to achieve comparable results through the force estimation scheme. The BW model of hysteresis is defined by four shape parameters that are not straightforwardly related to physical quantities. The influence of these parameters on the hysteresis loop, and the frequency response of the model, is demonstrated through a sensitivity analysis. This suggests that the model will fit to the softening overhang behaviour that was associated with the looseness of the axial joint in the literature. Two interpretations of identifying the model are discussed. Firstly the limit cycle is fitted to experimental data through a set of MATLAB functions that make use of analytical solutions to each branch of the loop. Secondly a minimisation is carried out between the output of the model and the measured response of the IHPA with a JH attached. This is achieved through Differential Evolution. It is not possible to identify a reliable model without an improved estimation of the input to the model. To make progress with this problem a number of contributions have been made. Simulations of the BW model have demonstrated that it is capable of describing the softening overhang behaviour that has been observed in the response of HPU devices and the subharmonic generation that descends from Contact Acoustic Nonlinearity. A methodical attempt to identify the parameters to this model from measurements of HPU test assemblies has been presented. A new force estimation scheme has been developed, which is based on a recent formulation of the Distributed Transfer Function Method. This provides a closed form route to estimating the force at an axial joint in a rod-like system. Regularisation methods have been applied to stabilise these estimations. An experimental configuration has been presented to test the force estimation scheme with observations from HPU test assemblies. These test assemblies have been analysed through electrical impedance analysis and Experimental Modal Analysis. This demonstrates changes in the behaviour of the assembly due to the introduction of the joint and its set tightness. Digital Image Correlation is presented as an alternative to finding the hysteresis behaviour at the axial joint which is subject to ultrasonic loading. Recommendations are made towards improving this set up.
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Rudolph, Kai. "Bargaining power effects in financial contracting : a joint analysis of contract type and placement mode choices /." Berlin : Springer, 2006. http://dx.doi.org/10.1007/3-540-34496-9.
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Bajuri, Norkhairul Hafiz. "Corporate Malaysia : essays on corporate governance, voting power, joint venture companies and ethnic Bumiputra corporate achievement." Thesis, Bangor University, 2010. https://research.bangor.ac.uk/portal/en/theses/corporate-malaysia-essays-on-corporate-governance-voting-power-joint-venture-companies-and-ethnic-bumiputra-corporate-achievement(89bc65f1-5a5a-4126-815e-c7f4fd4a5f67).html.
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This dissertation is on corporate Malaysia - a subject that spans both corporate governance and political economy. It deals with such issues as corporate ownership and control in the context of ethnicity. The first essay draws on the unique Malaysian experience to describe the possible unsuitability of the UK-US model of corporate governance for emerging economies. Examples from previous studies are used to highlight the unique relationship between ethnic Bumiputra economic interest and corporate governance. This essay also provides new statistics on the level of corporate control and highlights three areas of corporate governance as warranting further studies - technology, shareholders participation and application of voting power concept. The second essay introduces the basic concept of voting power as an alternative way of analysing corporate Malaysia. Data emanating from the Centre of Public Policy Studies 2006 (CPPS 2006) is analysed to illustrate this concept. A possible mismatch between the level of corporate ownership and the level of corporate control is illustrated. The third essay is on ethnic Chinese-Bumiputra joint venture companies as an equitable form of corporate ownership, as proposed by the CPPS (2006). Data from CPPS (2006) is analysed and a new framework of analysis is offered. Two stories emerge from our analysis. The study by the CPPS may have over-estimated the emergence of inter-ethnic joint ventures in Malaysia. The CPPS report also underestimates the difficulty of forming coalitions when shareholding within ethnic groups is dispersed. It remains to be seen if equitable control is also in the process of being achieved, since only a small percentage of companies listed in the stock exchange can be considered as inter-ethnic in the actual sense. Enriched information to highlight not just inter-ethnic but intra-ethnic distribution of equity is needed to shed light on potential coalitions across the ethnic divide. The fourth essay calls for greater application of the voting power concept in corporate governance studies. Special attention is placed on the Straffin index in view of its recent attention. This chapter concludes the Penrose-Banzhaf index as applicable with greater confidence despite general issues confronting this concept. The last essay is on ethnic Bumiputra' s corporate achievement. The first part focuses on corporate equity ownership by offering lawmakers as the basis for allocating shares in government-linked companies, hence an alternative equity ownership estimate. In the second part, the focus shifts to corporate control. Two observations are made: the intra-ethnic mismatch between equity and control and the inter-ethnic corporate control gap. In the latter observation, this gap reduces upon further analysis. Coalition with government entity increases ethnic Bumiputra's corporate control while small shareholders inactivity has an adverse influences on that of the ethnic Chinese group. The combined influences are corporate control increases for ethnic Bumiputra group but for ethnic Chinese group, reduction hence narrowing the gap. The influence of government coalition is expected. The influence of small shareholders inactivity to corporate control is however less expected.
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Skuna, Jiraphan. "International joint venture negotiation behaviour outcome : the role of bargaining power, culture and trust : qualitative case studies." Thesis, City University London, 2000. http://openaccess.city.ac.uk/8224/.
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Most of the literature on joint ventures (JVs) in developing countries has been viewed from the perspective of the foreign partners, ignoring the strategic imperatives and goals of the host country partners. Additionally, there has been very little research on international joint ventures (IJVs) in Thailand. Therefore, a study of the relationships between bargaining power, trust and culture affecting negotiation behaviour and outcomes (JV performance) could clarify and complement the results of past studies. It could lead foreign and Thai investors to better understand what they should do before and after entering into JVs, so as to achieve an effective performance (outcome), the success of IJV, cost minimization and profit maximization. This study examines the variables mentioned above in the context of service industries (e.g. construction, leasing, gas distribution), within the confines of joint venture theory and negotiation theory. The data was gathered using both questionnaires and in-depth interviews with a number of MDs and senior managers of JV firms. Both Thai and foreign parents were interviewed where possible. The result of the study shows that relationships between bargaining power, trust, culture, negotiation behaviour and performance (outcome) exist. A significant external factor affecting JV performance was also identified. Case studies were used as a research strategy for this study. 'Pattern matching logic' and 'explanation building' techniques were used for the analysis of data. In addition, data display technique was added to offer a clear understanding and picture of the results of the study. Regarding JV management and negotiation, this study demonstrated that each JV partner should pay attention and time to support the development of mutual trust and cultural understanding in order to avoid conflict and enhance a successful JV performance. This study also revealed the effect of bargaining power, trust and culture on JV performance mediated by negotiation tactics. This has received little attention in previous studies.
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Yuan, Shaoyu. "Comparison of wind stress algorithms, datasets and oceanic power input." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/47847.
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Thesis (S.M.)--Joint Program in Physical Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2009.Includes bibliographical references (leaves 49-51).
If the ocean is in a statistically steady state, energy balance is a strong constraint, suggesting that the energy input into the world ocean is dissipated simultaneously at the same rate. Energy conservation is one of the most important principles in the natural world. However, the study of energy balance in the oceanic circulation has long been overlooked. Mink and Winch (1998) proposed that energy is needed to maintain the meridional overturning circulation and they also concluded that the wind energy input into the world ocean constitute the most important part. Since then, many estimates on the wind energy input have been given with a focus on different time and spatial scales. It is well known that it is the air-sea momentum flux (wind stress) that actually drives the ocean circulation, especially the upper layer circulation. Due to the difficulties of directly measuring the wind stress, different algorithms were proposed to relate the wind stress with the wind velocity and other related atmospheric and oceanic variables. Different algorithms in fact produce quite different wind stresses, which may leads to spurious estimates in the wind energy input into the world ocean. The thesis is organized as follows. In chapter 1, we try to understand the difference of four bulk algorithms, and conclude that different bulk algorithms may yield the wind energy input differences of 20%. Comparison of 4 different wind stress dataset were presented in Chapter 2. However, we do not determine which product is the best. In Chapter 3, a simple numerical experiment was executed and some preliminary estimate on the effects of introducing the wind stress dependence on the oceanic surface velocity were given. The ECCO data computation, however, does not produce the results as expected and some explanations are given.
by Shaoyu Yuan.
S.M.
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Meier, Tobias [Verfasser]. "High-power CW green lasers for optical metrology and their joint benefit in particle physics experiments / Tobias Meier." Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2011. http://d-nb.info/101733546X/34.
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SILVA, ALEXANDRE MOREIRA DA. "TWO-STAGE ROBUST OPTIMIZATION MODELS FOR POWER SYSTEM OPERATION AND PLANNING UNDER JOINT GENERATION AND TRANSMISSION SECURITY CRITERIA." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2014. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=24754@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
Recentes apagões em todo o mundo fazem da confiabilidade de sistemas de potência, no tocante a contingências múltiplas, um tema de pesquisa mundial. Dentro desse contexo, se faz importante investigar métodos eficientes de proteger o sistema contra falhas de alguns de seus componentes, sejam elas dependentes e/ou independentes de outras falhas. Nesse sentido, se tornou crucial a incorporação de critérios de segurança mais rigorosos na operação e planejamento de sistemas de potência. Contingências múltiplas são mais comuns e desastrosas do que falhas naturais e independentes. A principal razão para isso reside na complexidade da estabilidade dinâmica de sistemas de potência. Além disso, o sistema de proteção que opera em paralelo ao sistema de distribuição não é livre de falhas. Portanto, interrupções naturais podem causar contingências em cascata em decorrência do mau funcionamento de mecanismos de proteção ou da instabilidade do sistema elétrico como um todo. Nesse contexto, se dá a motivação pela busca de critérios de segurança mais severos como, por exemplo, o n - K, onde K pode ser maior do que 2. Nesse trabalho, o principal objetivo é incorporar o crtitério de segurança geral n-K para geração e transmissão em modelos de operação e planejamento de sistemas de potência. Além de interrupções em geradores, restrições de rede, bem como falhas em linhas de transmiss˜ao também são modeladas. Esse avanço leva a novos desafios computacionais, para os quais formulamos metodologias de solução eficientes baseadas em decomposição de Benders. Considerando operação, duas abordagens são apresentadas. A primeira propõe um modelo de otimização trinível para decidir o despacho ótimo de energia e reservas sob um critério de segurançaa n - K. Nessa abordagem, a alta dimensionalidade do problema, por contemplar restrições de rede, bem como falhas de geradores e de linhas de transmissão, é contornada por meio da implícita consideração do conjunto de possíveis contingências. No mesmo contexto, a segunda abordagem leva em conta a incerteza da carga a ser suprida e a correlação entre demandas de diferentes barras. Considerando planejamento de expansão da transmissão, outro modelo de otimização trinível é apresentado no intuito de decidir quais linhas de transmissão, dentro de um conjunto de candidatas, devem ser construídas para atender a um critério de segurança n - K e, consequentemente, aumentar a confiabilidade do sistema como um todo. Portanto, as principais contribuições do presente trabalho são as seguintes: 1) modelos de otimização trinível para considerar o critério de segurança n - K em operação e planejamento de sistemas de potência, 2) consideração implícita de todo o conjunto de contingências por meio de uma abordagem de otimização robusta ajustável, 3) otimização conjunta de energia e reserva para operação de sistemas de potência, considerando restrições de rede e garantindo a entregabilidade das reservas em todos os estados pós-contingência considerados, 4) metodologias de solução eficientes baseadas em decomposição de Benders que convergem em passos finitos para o ótimo global e 5) desenvolvimento de restrições válidas que alavancam a eficiência computacional. Estudos de caso ressaltam a eficácia das metodologias propostas em capturar os efeitos econômicos de demanda nodal correlacionada sob um critério de segurançaa n - 1, em reduzir o esfor¸co computacional para considerar os critérios de seguran¸ca convencionais n-1 e n-2 e em considerar critérios de segurança mais rigorosos do que o n - 2, um problema intratável até então.
Recent major blackouts all over the world have been a driving force to make power system reliability, regarding multiple contingencies, a subject of worldwide research. Within this context, it is important to investigate efficient methods of protecting the system against dependent and/or independent failures. In this sense, the incorporation of tighter security criteria in power systems operation and planning became crucial. Multiple contingencies are more common and dangerous than natural independent faults. The main reason for this lies in the complexity of the dynamic stability of power systems. In addition, the protection system, that operates in parallel to the supply system, is not free of failures. Thus, natural faults can cause subsequent contingencies (dependent on earlier contingencies) due to the malfunction of the protection mechanisms or the instability of the overall system. These facts drive the search for more stringent safety criteria, for example, n - K, where K can be greater than 2. In the present work, the main objective is to incorporate the joint generation and transmission general security criteria in power systems operation and planning models. Here, in addition to generators outages, network constraints and transmission lines failures are also accounted for. Such improvement leads to new computational challenges, for which we design efficient solution methodologies based on Benders decomposition. Regarding operation, two approaches are presented. The first one proposes a trilevel optimization model to decide the optimal scheduling of energy and reserve under an n - K security criterion. In such approach, the high dimensionality curse of considering network constraints as well as outages of generators and transmission assets is withstood by implicitly taking into account the set of possible contingencies. The second approach includes correlated nodal demand uncertainty in the same framework. Regarding transmission expansion planning, another trilevel optimization model is proposed to decide which transmission assets should be built within a set of candidates in order to meet an n - K security criterion, and, consequently, boost the power system reliability. Therefore, the main contributions of this work are the following: 1) trilevel models to consider general n - K security criteria in power systems operation and planning, 2) implicit consideration of the whole contingency set by means of an adjustable robust optimization approach, 3) co-optimization of energy and reserves for power systems operation, regarding network constraints and ensuring the deliverability of reserves in all considered post-contingency states, 4) efficient solution methodologies based on Benders decomposition that finitely converges to the global optimal solution, and 5) development of valid constraints to boost computational efficiency. Case studies highlight the effectiveness of the proposed methodologies in capturing the economic effect of nodal demand correlation on power system operation under an n - 1 security criterion, in reducing the computational effort to consider conventional n-1 and n-2 security criteria, and in considering security criteria tighter than n - 2, an intractable problem heretofore.
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Yu, Bo Ren, and 余博仁. "High-Power Millimeter-Wave Rotary Joint." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/74914525445193056564.
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Hu, Shiang-Chun, and 胡翔竣. "Joint Diversity and Power Control for MIMO Systems." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/44881420995402947316.
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碩士國立暨南國際大學
通訊工程研究所
95
Both power control and antenna arrays techniques can reduce the cochannel interference. In this thesis, we combine the two techniques to get better system performance. We also consider a more general case of system where both mobiles and base stations have transmitter and receiver antenna arrays. We use two algorithms to find antenna array weight vectors at both transmitters and receivers as well as the transmitter powers with one of the following two objectives: 1) to maximize the minimum signal-to-interference-and-noise ratio (SINR) over all receivers and 2) to minimize the sum of the total transmitted power satisfying the SINR requirements at all links. From the numerical results, we found the system using antenna arrays have higher SINR and lower power consumption than the system using omnidirectional antennas.
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Tung, Kun-Hsien, and 董昆憲. "Optimized backlight power saving algorithm using joint power-PSNR characteristics among multiple frames." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/23468495877984672506.
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碩士中原大學
電子工程研究所
105
In this thesis, an optimized backlight power saving algorithm using joint power-PSNR characteristics among multiple frames is proposed. In existing state-of-the-art methods, the optimal decision for clipping point is made only with consideration of current frame, and the target frame PSNR are set the same for all frames. Therefore they have the same power-PSNR performance. In the proposed work, we show that better power-PSNR performance can be achieved by assigning different target frame PSNR for different frames. In the proposed algorithm, the decisions for clipping points associated with all frames are made at once. The inefficiency ratio of each clipping point is evaluated and put into the algorithm design. An optimization problem is formulated, and a solution-search procedure is proposed. Compared with state-of-the-art methods, the proposed work performs better in both aspects of power and PSNR; the BD-PSNR and the BD-Power of the proposed work against all other methods are better for every tested video; the BD-PSNR and the BD-Power can be as high as 15.25 dB on average, and the BD-Power can be as low as -23.56% on average.
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Gong, Xiaowen. "Joint bandwidth and power allocation in wireless communication networks." Master's thesis, 2010. http://hdl.handle.net/10048/1251.
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This thesis consists of two studies on joint bandwidth and power allocation strategy for wireless communication
networks. In the first study, joint bandwidth and power allocation strategy is proposed for wireless multi-user networks without relaying and with decode-and-forward relaying. It is shown that the formulated resource allocation problems are convex and, thus, can be solved efficiently. Admission control problem based on the joint bandwidth and power allocation strategy is further considered, and a greedy search algorithm is developed for solving it efficiently. In the second study, joint bandwidth
and power allocation strategy is presented for maximizing the sum ergodic capacity of secondary users under fading channels in cognitive radio networks. Optimal bandwidth allocation is derived in closed-form for any given power allocation. Then the structures of optimal power allocations are derived. Using these structures, efficient algorithms are developed for finding the optimal power allocations.Communications
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Lee, Chiao, and 李橋. "Joint Subcarrier Allocation and Power Control for OFDMA Femtocells." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/23589213494115005605.
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Hou, Yu-Chen, and 侯語辰. "Ka-band High Power Dual-Channel Microwave Rotary Joint." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/36854430732318688580.
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碩士國立清華大學
物理系
101
High power, multi-channel microwave rotary joint plays a critical role in radar systems. This thesis proposes the high power designs of circular TE01 and TM01 mode converters respectively. Due to the orthogonality of the field profile between TE01 and TM01 mode, a pair of the high power, dual-mode converters with back-to-back connection can be developed into a high isolation, dual-channel microwave rotary joint. HFSS is employed to separately design every component. Considering the effect of the cutoff frequency, TM01 wave must pass through the cutoff section of the TE01 mode converter. The connecting section is important for the converting efficiency, the operating bandwidth, and the isolation for the dual-mode converter. A gap for implanting a bearing exists in the middle channel of the rotary joint, therefore, a microwave choke is designed to prevent the leakage of TM01 wave. The experimental result yields a broad -1-dB transmission bandwidth of 15% for both TE01 and TM01 channels. The operating bandwidth for dual channels is highly overlapped with a high isolation of -50-dB between the channels. The transmission efficiency is independent of rotated angles since the field profile of TE01 mode and TM01 mode are azimuthal symmetric.
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Hsu, Sz-Yan, and 許斯晏. "Joint Power Assignment and Relay Location Design in Cooperative Power-Efficient Two-hop Networks." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/29652177341715128015.
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碩士國立暨南國際大學
通訊工程研究所
99
Cooperative relaying networks is a promising power-saving solution for the next-generation wireless networks due to short-range communications and low power. To design a high capacity power-efficient cooperative network, we should consider the tradeoff between power saving and user throughput. Specifically, lowering the transmission power can save power, but may degrade user throughput. Besides transmission power, relay location also impacts user throughput. Therefore, to achieve the tradeoff between power saving and throughput guarantee, we apply an optimization approach to jointly design the relay location and the power levels for base stations (BSs) /relay stations(RSs). The optimization objective aims maximizing the power efficiency of the cooperative network, subject to the requirements of user throughput and link reliability. In the cooperative networks, one user can choose direct, legacy two-hop relaying, or cooperative relaying transmission mode (TX-mode) for data transmissions. This thesis compares two TX mode selection principles to decide which TX-mode will be used: throughput-oriented (TO) and signal strength-oriented (SSO) selection principles. Numerical results show that TO selection principle can yield higher throughput and power efficiency than the SSO selection principle. Moreover, by properly designing the relay location and transmission power, both the goals of power saving and throughput guarantee can be fulfilled in the power-efficient cooperative networks.
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Chen, Wei-Jen, and 陳威錚. "Joint Power Control and Rate Adaptation for the WCDMA system." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/40057533759255790660.
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碩士國立交通大學
電信工程系
90
Abstract Third generation systems are designed for multirate communication, it’s the most charming part of third generation. How to combine power control and choosing the suitable data rate is one of the most popular issues. If we can find an excellent solution for this problem, we believe we will have an obvious promoting in throughputs and system capacity. Design power control and rate control algorithm jointly is the main point of this work. Searching the suitable parameters that need for our algorithm to improve the performance. And we discuss how to set the target Eb/No in power control mechanism to complete the whole algorithm. Then we can apply this algorithm in real system and see its impressive performance in real worlds. At the beginning of this paper, we assume the suitable target Eb/No for certain channel is known. And we refer the guidelines in 3GPP to design “Constrained Power Based Rate Adaptation algorithm”. This algorithm considers power and rate control jointly, and using transmission power very efficiently. In the second part of this paper, we proposed “FER estimation based dynamic target Eb/No setting algorithm” to satisfy required FER when the channel is unknown. The impressive point of this algorithm is using less power to satisfy required FER. At the last part, we modify “FER estimation based dynamic target Eb/No setting algorithm” then we can use a short time to find suitable target Eb/No for “Constrained Power Based Rate Adaptation algorithm” even the characteristic of the channel is unknown. Therefore, “Constrained Power Based Rate Adaptation algorithm” can show it’s excellent performance in real system.
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Awuor, Frederick Mzee. "Distributed joint power and rate adaption in ad hoc networks." 2011. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1000287.
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M. Tech. Electrical Engineering.This study proposes a distributive joint power and rate adaptation algorithm (JRPA) in ad hoc networks based on coupled interference minimisation. In the proposed method, the influence of coupled interference was controlled by dynamically adjusting network users' transmit power choices. The users are therefore aware of the current link status while determining their data rates. In addition, every maximize utility of other users as it maximizes its utility due to the inevitable cooperation, hence, improving a collective network performance. Solving this network utility maximization problem results in a supermodular game equivalence where users cooperate to maximise both local and global utility, hence the supermodular game theory concept was used to analyse the optimality and convergence of the proposed solution.
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Tsou, Yao-Chun, and 鄒曜駿. "Joint Clusterization and Power Allocation for Cloud Radio Access Network." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/57398476295819895668.
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碩士國立交通大學
電信工程研究所
104
In this paper, the cloud radio access network (C-RAN) is considered to extend the transmission coverage via the distributed deployment of large scale remote radio units (RRUs). The benefits of C-RAN system deployment is distributed network with centralized management solution. The RRUs are more closer to the user equipments (UEs), power consumption can be reduced to overcome pathloss attenuation and enhance spectral and energy efficiency (EE). However, this type of structure can induce considerable computational loadings due to the centralized management mechanisms. To reduce the complexity incurred in the C-RAN architecture, the clusterization technique is designed to categorize those RRUs into several groups. For the purpose of enhancing EE as well as the consideration of computational complexity, the joint clusterization and power allocation schemes are proposed to obtain the better tradeoff under the quality-of-service (QoS) requirement for each UE. The optimization problem is modeled as mixed combinatorial problem. To obtain the near-optimal solution without any problem transformation, the stochastic joint clusterization and power allocation (S-JCPA) scheme is proposed to jointly solve the problem with cross-entropy (CE) algorithm. In addition, reducing the complexity incurs from stochastic process, the deterministic joint clusterization and power allocation (D-JCPA) schemes are also proposed. By converting the problem into convex problem and using derivation information to find the clusterization and power allocation policies. Moreover, this joint optimization problem can be divided into two sub-problems, each of which is solved by iterative algorithm. Therefore, the iterative times in D-JCPA scheme can be reduced. In addition, as large number of RRUs are deployed in the C-RAN system, the large random theorem with convex properties can be applied to derive asymptotic form for performing D-JCPA scheme. Finally, the complexity of the proposed method has been analyzed. Simulation results show that the proposed algorithms can provide better performance gain than the existing method.
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Hardyk, Andrew Timothy Todd. "Force- and power-velocity relationships in a multi-joint movement." 2000. http://etda.libraries.psu.edu/theses/available/etd-1116100-134346/.
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Su, Wei-Hsin, and 蘇偉信. "Joint Equalization and Power Loading for Spectrally Orthogonally-Precoded OFDM Systems." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/20836842247067754423.
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碩士國立臺灣大學
電信工程學研究所
98
In this thesis, we combine Spectrally Orthogonally-Precoded OFDM System (SOP-OFDM) with power loading (PL) techniques in order to improve BER performance and provide very high spectral efficiency [1]. We propose the following two algorithms: 1. Joint equalization and block precoding in order to minimize mean square error of SOP-OFDM system 2. Block precoding design in order to minimize asymptotical average instantaneous bit error rate of SOP-OFDM system with MMSE equalizer. The BER performance of these two systems both outperforms the existing SOP-OFDM systems with power loading design by using Zero Forcing equalizer [1]. Eventually, on two-ray fading channels, we will compare average BER performance, mean square error performance, fractional out-of-band power characteristics and complexity of the spectral codes with different power loading algorithms.
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HUANG, WEI-RU, and 黃煒儒. "Joint Power and Admission Control for Cognitive Radio with Priority Mechanism." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/50217863483665975204.
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碩士國立東華大學
電機工程學系
101
Because of the rapid development of wireless networks, how to effectively improve the utilization of finite spectrum becomes an important issue. Cognitive Radio (CR) is a new technology which is able to optimize the utilization of spectrum. Since the primary users and the secondary users will transmit in the same spectrum, however, the signal - to - interference - plus - noise - ratio of primary users will be reduced. To ensure the quality of service (QoS) of primary users,we need to perform power control for secondary users. Simultaneously, we incorporate admission control to maximize the number of secondary users. In order to ensure secondary users' QoS, we propose a Priority Mechanism to avoid secondary users who are transmitting from being interrupted.
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Fan, Chih-Hao, and 范志豪. "Thermal compression process for power IC Attachment and the joint properties." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/34661538905296079697.
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碩士國立中興大學
材料科學與工程學系所
103
An urgent issue in electronic packaging is the die-attachment technique for high power ICs, such as SiC and GaN, which needs to withstand high operation temperature up to 250oC. For this purpose, this study developed a low-temperature soild-state direct bonding process for dissimilar metals. Experimental results show that Cu/Zn can be bonded successfully at 200oC under the loading of 10MPa for 30 minutes. The joints thus formed exhibited a shear strength up to 20MPa. If the thermal compression was performed at 300 oC, the shear strength of bonded Cu/Zn and Cu/Ni/Zn joints exceeded 50MPa, especially for Cu/Zn joint, the strength even reached 70MPa. Microstructural observation results indicate that in the as-bonded state CuZn5/Cu5Zn8 IMCs formed at the interface of Cu/Zn joints, while Ni5Zn21 formed at the interface of Cu/Ni/Zn joints and Cu5Zn8 formed locally between Ni5Zn21 and Cu substrate. With respect to high temperature mechanical properties, due to the softening of Zn, the shear strength of all the joints decreased with a higher testing temperature. During aging at 250 oC, the shear strength of Cu/Zn degraded drastically up to 500hr and after that the joint strength remained almost constant. The strength of Cu/Ni/Zn joints decreased gradually and maintained 30MPa for 500hr. The shear strength of both of the joints tended to be identical subjected to aging for 800hr. The deterioration of the joint strength during aging can be ascribed to the competitive growth between CuZn5 and Cu5Zn8 resulting in collapse and oxidation of CuZn5. The electroplated Ni and Ni5Zn21 thus formed can retard the excessive growth of Cu5Zn8 to some extent. According to interfacial morphology and elemental mapping, Ni-Zn IMCs existed between CuZn5/Cu5Zn8 up to 800hr. In addition, it was also verified that the oxidized Cu and Ni can be reduced by formic acid vapor formic acid vapor treatment. In contrast, formic acid vapor contaminated the surface of Zn and thereby C2H2O4Zn‧2H2O formed. The contamination of Zn surface is harmful for dissimilar metal bonding.
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Wang, Hai-Han, and 汪海瀚. "Joint Beamforming for Multicell Multigroup Multicast with Per-cell Power Constraints." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/50404665438379819082.
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碩士國立臺灣大學
電信工程學研究所
102
This thesis considers a joint beamforming design problem in the multicell multicast system with multiple groups that provide different multicast services using the same time-frequency resource. By jointly design beamforming vectors among cooperative cells, the worst received signal-to-interference-plus-noise-ratio (SINR) of all serving users in the multiple multicast groups can be improved. Inspired by previous works in the literature, we apply semidefinite relaxation (SDR) technique to perform joint beamforming design among the cooperating base stations. Per-cell power constraints are considered which makes solving the problem challenging. We propose two algorithms to accommodate the per-cell power constraints while performing joint beamforming. Simulation results show that the proposed algorithms provide better performance compared to the existing multicast methods in the multicell environment.
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Chang, Wen-Yao, and 張文耀. "A Joint Multicast Scheduling and Power Allocation Scheme for Cellular Systems." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/39347511015976740566.
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碩士國立臺灣大學
電信工程學研究所
101
Due to the nature of time-varying and frequency selective fading, wireless communication system can increase system throughput via dynamic resource allocation (time slot, bandwidth, power and bit), exploiting multi-user diversity. Multicast deliver the same content to several users in the same group to enhance frequency efficiency, but the channel conditions may vary greatly between users of the same group. Conventional approach selects the worst channel gain as equivalent channel gain of group’s sub-channel, limiting the system throughput. Aim to maximum frequency efficiency, we have to make appropriate trade-off between multi-user diversity gain and multicast gain. In addition to system throughput, fairness is another performance index of resource allocation. Considering orthogonal frequency division multiple access (OFDMA)-based wireless multicast system, firstly, we separately formulate different resource allocation as three simpler optimization problem — Link adaption of single group (Which data fragments can be correctly received by different users?), sub-channel assignment (Which group’s data can be transmitted over different sub-channels?) and power allocation — and propose corresponding algorithms successively. Subsequently, we formulate all resource allocation as a joint optimization problem and combine it with aforementioned algorithms to approach proportional fairness among users. Besides, we also consider more general case — One user may belong to more than two different groups (i.e., receives different data streams more than two simultaneously). Simulation results show that our proposed approaches have outer performance on system throughput as well as fairness among users.
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Wu, Yun-Pu, and 吳昀樸. "Joint Power Control and Rate Adaptation for Vehicular See-Through Systems." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/cs948p.
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碩士國立臺灣大學
電信工程學研究所
106
The tendency towards the usage of vehicular communications to enhance driving experiences is attractive and inevitable, and thus the cooperative advanced driver assistance system (co-ADAS) is able to promote the road safety and efficiency by exchanging the information of traffic among some of the vehicles. The majority of related work focus on transmission of the light safety message under different vehicle density. There are a few works discuss on heavy data communications with stringent latency constraints. In this thesis, we focus on the heavy data communications, and even adopt continuous packet transmission as a serious criterion to cover diverse vehicular applications. We consider the rate adaptation, which supports weighted fairness for safety or non-safety messages, designed for vehicular environments. Moreover, we take into account practical problems encountered when utilizing the power control for the packet transmission in VANET, and a new power control strategy is proposed. In order to address the presence of various uncertainties in VANET, we propose an algorithm based on stochastic optimal control techniques. The more sensitive exponential cost function is used to further minimize the SINR deviation and also end-to-end delay. For instant decisions, the exogenous inputs support comparison of conditions for power control and rate adaptation at any time. Evaluation results show that the proposed algorithm outperforms the method considering delay minimization in static ad hoc networks. We can achieve the similar performance while interference increases but only consume less than half power saving about 61 mW and 57 mW. The delivery ratio is higher 12.11% but consumes less power while no neighboring pair. The proposed method consumes the appropriate power and achieves the higher packet delivery and the lower packet delay ratio. Besides, the power consumption is decreasing while vehicle density increases, which is suitable for VANET.
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Gupta, Divya K. "Joint Scheduling, Routing and Power Control for Single-Channel Wireless Mesh Networks." 2006. http://www.lib.ncsu.edu/theses/available/etd-08272006-165858/unrestricted/etd.pdf.
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Chang, Chia-Yu, and 張家瑜. "Power-efficient Joint Transmitter-Receiver Beamformer Design for Wireless Ad Hoc Network." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/j2r3sv.
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碩士國立臺灣大學
電子工程學研究所
98
Wireless Ad Hoc network, in recent several years, has been widely thought of as another possible development direction in wireless network in contrast with traditional infrastructure based wireless network. Because wireless ad hoc network doesn’t need any time or cost spent on infrastructure construction, so it can be used in remote area or the place where doesn’t exist any infrastructure. And because of its distributive nature, ad hoc network is more robust compared to traditional wireless network. Due to several unique advantages, wireless ad hoc network makes more researchers and engineers pay more attention to it. In this thesis, an ad hoc network operation flow chart is proposed based on ad hoc network feature and 802.11 Ad Hoc mode standard. And in this flow chart, we have two communication scenarios in wireless ad hoc network: unicast and multicast. So, we will design the joint transmitter-receiver beamformer algorithm at both ends to utilize the power-saving and interference-mitigation characteristics of beamforming. And both two characteristics are important to build up a power-efficient transceiver in wireless ad hoc network. After each of the two beamforming design algorithms, we will make some simulation results and compared with some existing algorithms to see its performance. From the comparison result, we can find these two beamforming design algorithms are efficient in reducing the transmit power. Here we will discuss the detail derivations in how to design these two types of beamforming algorithms.
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Hsieh, Chia-Chin, and 謝佳縉. "Joint Compliance Effects on the Propulsion Power of a Biomimetic Underwater Vehicle." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/84743823972371477949.
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碩士國立臺灣大學
工程科學及海洋工程學研究所
96
Animals improve their energy efficiency and adapt to changes in task requirements or in environmental conditions by controlling joint compliance dynamically. This work mimics fish’s propulsion using a compliant tail fin to show the power reduction while the fish propels by the tail fin. A compliance control scheme of caudal joint for a biomimetic autonomous underwater vehicle (BAUV) is presented. The scheme is based on actuators arranged antagonistically about joints. Design considerations on the hardware are presented to reduce the power consumption from actuators and emulate the underlying mechanics fish use to produce movement. Oscillation motions of the tail fin are driven by motors through springs. A state space model and a way-point tracking controller for the BAUV system are presented. A method is derived to determine the optimal spring compliance. Simulations are performed to verify the existence of the optimal joint compliance. Water tank experiments using a BAUV demonstrate that tuning joint compliances can reduce the amount of energy required for the propulsion of the tail fin.