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Haque, Syed E. "Efficient GTS Allocation Schemes for IEEE 802.15.4." Digital Archive @ GSU, 2012. http://digitalarchive.gsu.edu/cs_theses/75.
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IEEE 802.15.4 is a standard defined for wireless sensor network applications with limited power and relaxed throughput needs. The devices transmit data during two periods: Contention Access Period (CAP) by accessing the channel using CSMA/CA and Contention Free Period (CFP), which consists of Guaranteed Time Slots (GTS) allocated to individual devices by the network coordinator. The GTS is used by devices for cyclic data transmission and the coordinator can allocate GTS to a maximum of only seven devices. In this work, we have proposed two algorithms for an efficient GTS allocation. The first algorithm is focused on improving the bandwidth utilization of devices, while the second algorithm uses traffic arrival information of devices to allow sharing of GTS slots between more than seven devices. The proposed schemes were tested through simulations and the results show that the new GTS allocation schemes perform better than the original IEEE 802.15.4 standard.
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Maldonado, Martin Froilan. "A comparison of file allocation decision-making schemes." Diss., Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/9148.
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Vannithamby, Rathneswaran. "Resource allocation schemes for high speed wireless access networks." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/NQ63644.pdf.
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Li, Guangming. "Novel resource allocation schemes in optical burst switching networks." Click to view the E-thesis via HKUTO, 2006. http://sunzi.lib.hku.hk/hkuto/record/B37051040.
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Phuyal, Umesh. "Resource allocation schemes for next generation wireless communication systems." Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/43711.
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Recent studies have indicated that spectrum scarcity in next generation wireless networks is inevitable due to the surge of mobile communication usage which offers the capability of instant access to users’ data and multimedia content anywhere anytime. Demand of mobile data traffic is found to have doubled within a year, and is expected to grow by 15 times in about five years. Fulfilling such mounting demand with the limited radio resources is a huge challenge for next generation wireless communication systems. Moreover, meeting the diverse quality of service (QoS) requirements of various types of user applications is indispensable. To tackle these challenges and to improve the spectral efficiency, radio resource management needs to be optimized for various novel systems such as relay-based cooperative transmission technique and opportunistic spectral utilization using cognitive radio (CR) technology. In addition to spectral efficiency, effective resource allocation methods need to be designed to improve the energy efficiency of such systems to achieve sustainable green communication.
In this thesis, we investigate performance of certain resource allocation techniques in next generation wireless communication systems through analytical modeling and propose improved solutions using results from these models and simulations. First, we analyze the performance of resource allocation schemes for guaranteed QoS provisioning in a relay-based cooperative communication system. We introduce novel methods for precoder design for multi-antenna source and relay stations employing joint zero-forcing method. We design various schemes to allocate available transmit power to the source and relay(s) in a spectrally efficient manner. Next, we study the performance of resource allocation schemes for multicarrier multiple-input multiple-output (MIMO)-based CR system. We propose an optimal power allocation scheme for such system considering the practical CR constraints. Finally, we investigate the issues and challenges in enabling green communication in next generation wireless communication systems. We propose energy-efficient resource allocation method for guaranteed QoS provisioning by employing relay-based cooperative communication. We also analyze the intrinsic trade-off between energy and spectral efficiency using multi-objective optimization approach. For all of the proposed algorithms and schemes, we also present extensive simulation-based results for comparison with methods existing in the literature.
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Li, Guangming, and 李光明. "Novel resource allocation schemes in optical burst switching networks." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B37051040.
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Lee, Joohee. "CDMA overlapped carrier allocation schemes for cellular mobile communications." Thesis, University of Surrey, 1997. http://epubs.surrey.ac.uk/844189/.
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The following various multiple access schemes based on CDMA are investigated: Hybrid OCA-FD/SC-CDMA: Whereas conventional FD/SC-CDMA schemes do not permit adjacent carrier spectra to overlap, this scheme overlaps adjacent carrier spectra intentionally. Even though interference arises from adjacent carrier, higher chance of multipath diversity and spectrally efficiency is achieved in comparison with conventional FD/SC-CDMA. It will be shown that OCA compensates for capacity loss incurred by subdivision of available spectrum for frequency division multiplexing, and also achieves even higher capacity for chip waveforms with smooth spectral shape at no extra system complexity while merits of FD/CDMA such as lower complexity and higher diversity gain for noncoherent reception are still fully exploited. In terms of capacity, for flat fading channel and rectangular pulse cut off at mainlobe-null in frequency domain, FD/SC-CDMA combined with OCA schemes gives roughly 56% gain in comparison with SC-CDMA and conventional FD/SC-CDMA. For frequency selective channel and noncoherent reception, even higher gain is achievable. Hybrid slow frequency hopping (SFH)/SC-CDMA: Overlapped carrier allocation (OCA) schemes can be applied to hybrid SFH/SC-CDMA. In power controlled systems, SFH/SC-CDMA is known to be much worse than pure DS-CDMA in terms of capacity. Introduction of OCA to SFH/SC-CDMA improves capacity significantly, and consequently it becomes comparable to pure DS-CDMA whilst merits of frequency hopping such as strong immunity to near/far effect is preserved. FD/MC-CDMA: In this scheme, available spectrum is subdivided into multiple discrete subspectra, and they are interleaved. Then diversity gain becomes equal to that of ordinary MC-CDMA frequency diversity. As a result of less subcarriers than ordinary MC-CDMA, equaliser becomes less complicated. Guard interval imposed to overcome timing synchronisation error and intersymbol interference helps to suppress inter-subcarrier interference. Successive subcarriers are apart by multiple of the chip rate, and so inter-subcarrier interference is reduced or nearly rejected. In FD/MC-CDMA, longer guard interval instead of windowing is more effective. SFH/MC-CDMA: This scheme replaces hardware implementation of frequency hopping with simple coding technique. Hence frequency hopping gives no extra hardware complexity unlike SFH/SC-CDMA. Even fast frequency hopping can be simply implemented. Likewise in FD/MC-CDMA, frequency diversity is fully exploited. In the absence of nonlinear distortion, FD/MC-CDMA outperforms other multiple access schemes under consideration in terms of capacity, hardware complexity, and flexibility of resource management in single rate and multi-rate applications. In practice, power-limited mobile terminals can not afford to impose sufficient output backoff on power amplifier, and consequently nonlinearity generates intermodulation products (IMP). IMP's degrade signal-to-noise ratio and make synchronisation even more difficult. Unlike narrow-band OFDM, intermodulation products become noise-like after despreading at the receiver, and so cross-talk does not happen. Flexibility in pulse shape, carrier frequency, and the width of spectrum makes performance analysis more troublesome.
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Stemick, Martin. "Contributions to Resource Allocation Schemes in Multiuser OFDM-FDMA-Systems /." Göttingen : Cuvillier, 2009. http://deposit.d-nb.de/cgi-bin/dokserv?id=3415355&prov=M&dok_var=1&dok_ext=htm.
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Hamayun, Mirza Tariq. "Integral sliding mode fault tolerant control schemes with control allocation." Thesis, University of Leicester, 2013. http://hdl.handle.net/2381/28107.
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The key attribute of a Fault Tolerant Control (FTC) system is to maintain overall system stability and acceptable performance in the face of faults and failures within the system. In this thesis new integral sliding mode (ISM) control allocation schemes for FTC are proposed, which have the potential to maintain the nominal fault free performance for the entire system response, in the face of actuator faults and even complete failures of certain actuators. The incorporation of ISM within a control allocation framework uses the measured or estimated values of the actuator effectiveness levels to redistribute the control effort among the healthy actuators to maintain closed-loop stability. This combination allows one controller to be used in both fault free as well as in fault or failure situations. A fault tolerant control allocation scheme which relies on an a posteri approach, building on an existing state feedback controller designed using only the primary actuators, is also proposed. Retro-fitting of an ISM scheme to an existing feedback controller is advantageous from an industrial perspective, because fault tolerance can be introduced without changing the existing control loops. To deal with a wider range of operating conditions, the fault tolerant features of ISM are also extended to linear parameter varying systems. A FTC scheme considering only the availability of measured system outputs is also proposed, where now the feedback controller design is based on the estimated states. In each of the ISM fault tolerant schemes proposed, a rigorous closed-loop analysis is carried out to ensure the stability of the sliding motion in the face of faults or failures. A high fidelity benchmark model of a large transport aircraft is used to demonstrate the efficacy of the new FTC schemes.
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Bocquet, Wladimir. "Computationally Efficient Power Allocation and Equalization Schemes for Multi-Carrier Systems." 京都大学 (Kyoto University), 2009. http://hdl.handle.net/2433/123833.
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Grünheid, Rainer. "Adaptive resource allocation schemes in MIMO-OFDM based cellular communication systems /." Göttingen : Cuvillier, 2007. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=016325665&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
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Devarajan, Rajiv. "Power allocation schemes for cooperative communication system using weighted sum approach." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/36957.
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This thesis investigates power allocation schemes for an amplify-and-forward dual-hop relay based cooperative communication system with perfect and imperfect channel state information (CSI). We define cost functions and propose power allocation schemes such that the cost functions are minimized. We analyze a multiuser system, where we select the best user for transmission, who incurs the least cost of transmission. In a practical system, estimated CSI is often imperfect. We assume the estimated CSI is affected by estimation errors, which are modeled as zero mean complex Gaussian. First we propose an optimization scheme where the objective is to minimize the weighted sum of source and relay powers. Then we propose a more general multi-objective optimization scheme which jointly optimizes sum power and signal-to-noise ratio (SNR). In our proposed schemes, source and relay nodes share a fixed total power, and transmission is allowed only if the minimum required SNR at the destination can be achieved with the available power budget. These schemes are analyzed under both perfect and imperfect CSI assumptions. In addition to proving the convexity of these problems, we propose analytical solutions for sum power minimization and SNR maximization schemes in the presence of imperfect CSI. Performance of the systems under the proposed schemes are investigated in terms of energy efficiency, throughput and outage. Simulation results show that proposed schemes reduce wastage of power by avoiding unsuccessful transmissions.
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Grünheid, Rainer. "Adaptive resource allocation schemes in MIMO-OFDM based cellular communication systems." Göttingen Cuvillier, 2006. http://d-nb.info/986383627/04.
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Kaya, Onur. "Achievable rates, optimal signalling schemes and resource allocation for fading wireless channels." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2948.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2005.Thesis research directed by: Electrical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Khreis, Alaa. "Cross-layer optimization of cooperative and coordinative schemes for next generation cellular networks." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLT011/document.
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Les demandes de haut débit, faible latence et grande fiabilité augmentent dans les nouvelles générations de systèmes de radiocommunications. Par conséquent, on propose de combiner la transmission non orthogonale avec les retransmissions HARQ afin de combattre les fluctuations de canal de transmission à haut débit. Dans la première partie de la thèse, on propose des protocoles de retransmissions HARQ avec l'aide d'un relai afin d'améliorer le débit et la fiabilité du système. Une version renforcée du protocole HARQ qui prend en compte le délai de retour est proposée dans la seconde partie de la thèseHARQ has become an important research field in the wireless digital communications area during the last years. In this thesis, we improve the HARQ mechanisms in terms of throughput and/or latency which are the bottleneck of next generation wireless communication systems. More precisely, we improve the time-slotted HARQ systems by mimicking NOMA, which means using superposed packets in a single-user context. In the first part of the thesis, we propose HARQ protocols using the help of a relay to improve the transmission rate and reliability. An enhanced HARQ protocol adapted to delayed feedback is proposed in the second part. In this new multi-layer HARQ protocol, additional redundant packets are sent preemptively before receiving the acknowledgement, and in superposition to other HARQ processes
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El, Houmaidi Mounire. "RESOURCE ALLOCATION SCHEMES AND PERFORMANCE EVALUATION MODELS FOR WAVELENGTH DIVISION MULTIPLEXED OPTICAL NETWORKS." Doctoral diss., University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4331.
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Wavelength division multiplexed (WDM) optical networks are rapidly becoming the technology of choice in network infrastructure and next-generation Internet architectures. WDM networks have the potential to provide unprecedented bandwidth, reduce processing cost, achieve protocol transparency, and enable efficient failure handling. This dissertation addresses the important issues of improving the performance and enhancing the reliability of WDM networks as well as modeling and evaluating the performance of these networks. Optical wavelength conversion is one of the emerging WDM enabling technologies that can significantly improve bandwidth utilization in optical networks. A new approach for the sparse placement of full wavelength converters based on the concept of the k-Dominating Set (k-DS) of a graph is presented. The k-DS approach is also extended to the case of limited conversion capability using three scalable and cost-effective switch designs: flexible node-sharing, strict node-sharing and static mapping. Compared to full search algorithms previously proposed in the literature, the K-DS approach has better blocking performance, has better time complexity and avoids the local minimum problem. The performance benefit of the K-DS approach is demonstrated by extensive simulation. Fiber delay line (FDL) is another emerging WDM technology that can be used to obtain limited optical buffering capability. A placement algorithm, k-WDS, for the sparse placement of FDLs at a set of selected nodes in Optical Burst Switching (OBS) networks is proposed. The algorithm can handle both uniform and non-uniform traffic patterns. Extensive performance tests have shown that k-WDS provides more efficient placement of optical fiber delay lines than the well-known approach of placing the resources at nodes with the highest experienced burst loss. Performance results that compare the benefit of using FDLs versus using optical wavelength converters (OWCs) are presented. A new algorithm, A-WDS, for the placement of an arbitrary numbers of FDLs and OWCs is introduced and is evaluated under different non-uniform traffic loads. This dissertation also introduces a new cost-effective optical switch design using FDL and a QoS-enhanced JET (just enough time) protocol suitable for optical burst switched WDM networks. The enhanced JET protocol allows classes of traffic to benefit from FDLs and OWCs while minimizing the end-to-end delay for high priority bursts. Performance evaluation models of WDM networks represent an important research area that has received increased attention. A new analytical model that captures link dependencies in all-optical WDM networks under uniform traffic is presented. The model enables the estimation of connection blocking probabilities more accurately than previously possible. The basic formula of the dependency between two links in this model reflects their degree of adjacency, the degree of connectivity of the nodes composing them and their carried traffic. The usefulness of the model is illustrated by applying it to the sparse wavelength converters placement problem in WDM networks. A lightpath containing converters is divided into smaller sub-paths such that each sub-path is a wavelength continuous path and the nodes shared between these sub-paths are full wavelength conversion capable. The blocking probability of the entire path is obtained by computing the blocking probabilities of the individual sub-paths. The analytical-based sparse placement algorithm is validated by comparing it with its simulation-based counterpart using a number of network topologies. Rapid recovery from failure and high levels of reliability are extremely important in WDM networks. A new Fault Tolerant Path Protection scheme, FTPP, for WDM mesh networks based on the alarming state of network nodes and links is introduced. The results of extensive simulation tests show that FTPP outperforms known path protection schemes in terms of loss of service ratio and network throughput. The simulation tests used a wide range of values for the load intensity, the failure arrival rate and the failure holding time. The FTPP scheme is next extended to the differentiated services model and its connection blocking performance is evaluated. Finally, a QoS-enhanced FTPP (QEFTPP) routing and path protection scheme in WDM networks is presented. QEFTPP uses preemption to minimize the connection blocking percentage for high priority traffic. Extensive simulation results have shown that QEFTPP achieves a clear QoS differentiation among the traffic classes and provides a good overall network performance.Ph.D.
School of Computer Science
Engineering and Computer Science
Computer Science
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Musabe, Richard. "Optimizing VoIP in 3G LTE using cross-layered scheduling and resource allocation schemes." Thesis, Glasgow Caledonian University, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.601666.
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Wireless communication has been the major part of the wireless industry that have grown very fast and captured the attention of many researchers. it has evolved from different generations and the current 3G Long Term Evolution (LTE) is the main focus in this project. LTE is an emerging and promising technology that aims at providing broadband ubiquitous Internet access and improving multimedia services. This is achieved through streamlining the system for packet services, since LTE is an all Internet Protocol (IP) based network. The fact that 3G LTE is a packet based network brings about some improvements in the form of higher bit rates, lower latencies, etc. However, several technical challenges are expected to arise when voice traffic is transmitted over LTE network. Voice transmission over 3G LTE has brought major concerns due to the fact that voice traffic, similar to any other real-time traffic, is affected by technical issues such as end-ta-end delay or latency, jitter, and packet loss which adversely affect the Quality of Service (QoS). This has led to the development of different scheduling and resource allocation schemes with the aim of improving the QoS of voice traffic when transmitted over a 3G LTE network. This research, studies how cross-layered scheduling and resource allocation techniques can improve the QoS of voice traffic when transmitted over 3G LTE network. This research proposes a novel cross-layer scheduling and resource allocation algorithm in order to improve the performance gains and QoS of voice when transmitted over a 3G LTE Network. The novelty of the proposed algorithm is that it projects the voice packet scheduling and resource allocation problem as a constrained optimization problem in contrast to the existing techniques. This optimization problem is formulated using the transmission rate and channel state information at the physical layer as well as the queuing state information such as the queue length at the Medium Access Control (MAC) layer. The a1gorithmic implementation of the obtained solution is provided and this research also investigates the performance, mobility, complexity, and fairness issues of the proposed cross-layer scheduling algorithm under different conditions such as, VoIP delay, packet loss, etc.
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Girici, Tolga. "Resource allocation schemes for OFDMA based wireless systems with quality of service constraints." College Park, Md.: University of Maryland, 2007. http://hdl.handle.net/1903/7618.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2007.Thesis research directed by: Dept. of Electrical and Computer Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Gorantiwar, Sunil Digambar. "A model for the planning and operation of heterogeneous irrigation schemes in semi-arid regions under rotational water supply." Thesis, Loughborough University, 1995. https://dspace.lboro.ac.uk/2134/11706.
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This research is aimed at developing the method for efficiently using the water in irrigation schemes in semi-arid regions. These irrigation schemes are often short of water to irrigate entire culturable command area (CCA) with maximum water requirement of different crops and are characterised with different weather patterns, soils and the possibility to grow several crops. The CCA of these schemes is also large with several users or units, each having different characteristics. The previous research in this field was mostly either on optimum allocation of the resources considering the irrigation scheme as a whole or on evaluating the performance of the irrigation scheme for certain irrigation schedules for different units in the scheme. However in such schemes optimum allocation of resources (land and water) to different crops and their distribution over different units is important (optimum allocation plan, OAP). In the present study, the method and a computer model are developed to prepare OAPs for these irrigation schemes under rotational water supply, by incorporating the concepts of deficit irrigation and productivity and equity in the optimisation process. The previous research stressed the importance of equity observed in different ways but seldom adopted in optimum allocation of resources. Therefore this method includes the preparation of OAPs while observing equity in allocation of land and water resources and distribution of crop production and net benefits. The developed model, Area and Water Allocation Model (A WAM), consists of four phases each one for generating irrigation strategies, preparing irrigation programme for each irrigation strategy, screening irrigation programmes and allocating resources optimally to different crops in different units. The A W AM estimates the irrigation water requirement, crop yield and net benefits by simulating the various process in the irrigation scheme, produces the OAPs at preseason planning with different scenarios of productivity and equity and management options, develops the steady OAP by considering the temporal variability in the weather and modifies the allocation plan optimally during the intraseasonal operation of the irrigation scheme. A W AM operates in seven different modes to achieve this. These are simulation, calibration, generation, optimisation, planning, operation and evaluation. The A W AM was applied to Nazare Medium Irrigation Project (medium lmgation scheme) in semi-arid region of Maharashtra State, India to evaluate the existing practice of irrigation (fixed depth irrigation), full depth irrigation and deficit irrigation for obtaining the OAPs. The practice of deficit irrigation was found to be beneficial over the existing approach and full depth irrigation. The OAPs at preseason planning are obtained for several alternatives and compared. The OAPs were obtained for different equity criteria. The productivity and equity were found to be inversely related. The method is proposed to obtain the stable OAP with A WAM by considering several years' data. The present research contributes towards efficient utilisation of water in the irrigation scheme by incorporating the deficit irrigation and productivity and equity in obtaining OAPs, developing the methods to obtain the steady OAP and modifying the allocation plan optimally during the intraseasonal operation of the irrigation scheme.
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Guo, Zhongyong. "Transportation schemes and bandwidth allocation for VBR MPEG-2 video traffic in ATM networks." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ31579.pdf.
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Kumar, Akshay. "Efficient Resource Allocation Schemes for Wireless Networks with with Diverse Quality-of-Service Requirements." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/87529.
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Quality-of-Service (QoS) to users is a critical requirement of resource allocation in wireless networks and has drawn significant research attention over a long time. However, the QoS requirements differ vastly based on the wireless network paradigm. At one extreme, we have a millimeter wave small-cell network for streaming data that requires very high throughput and low latency. At the other end, we have Machine-to-Machine (M2M) uplink traffic with low throughput and low latency. In this dissertation, we investigate and solve QoS-aware resource allocation problems for diverse wireless paradigms.
We first study cross-layer dynamic spectrum allocation in a LTE macro-cellular network with fractional frequency reuse to improve the spectral efficiency for cell-edge users. We show that the resultant optimization problem is NP-hard and propose a low-complexity layered spectrum allocation heuristic that strikes a balance between rate maximization and fairness of allocation. Next, we develop an energy efficient downlink power control scheme in a energy harvesting small-cell base station equipped with local cache and wireless backhaul. We also study the tradeoff between the cache size and the energy harvesting capabilities. We next analyzed the file read latency in Distributed Storage Systems (DSS). We propose a heterogeneous DSS model wherein the stored data is categorized into multiple classes based on arrival rate of read requests, fault-tolerance for storage etc. Using a queuing theoretic approach, we establish bounds on the average read latency for different scheduling policies. We also show that erasure coding in DSS serves the dual purpose of reducing read latency and increasing the energy efficiency.
Lastly, we investigate the problem of delay-efficient packet scheduling in M2M uplink with heterogeneous traffic characteristics. We classify the uplink traffic into multiple classes and propose a proportionally-fair delay-efficient heuristic packet scheduler. Using a queuing theoretic approach, we next develop a delay optimal multiclass packet scheduler and later extend it to joint medium access control and packet scheduling for M2M uplink. Using extensive simulations, we show that the proposed schedulers perform better than state-of-the-art schedulers in terms of average delay and packet delay jitter.PHD
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He, Zhenfeng. "Efficient radio resource allocation schemes and code optimizations for high speed downlink packet access transmission." Thesis, Imperial College London, 2010. http://hdl.handle.net/10044/1/6189.
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An important enhancement on the Wideband Code Division Multiple Access (WCDMA) air interface of the 3G mobile communications, High Speed Downlink Packet Access (HSDPA) standard has been launched to realize higher spectral utilization efficiency. It introduces the features of multicode CDMA transmission and Adaptive Modulation and Coding (AMC) technique, which makes radio resource allocation feasible and essential. This thesis studies channel-aware resource allocation schemes, coupled with fast power adjustment and spreading code optimization techniques, for the HSDPA standard operating over frequency selective channel. A two-group resource allocation scheme is developed in order to achieve a promising balance between performance enhancement and time efficiency. It only requires calculating two parameters to specify the allocations of discrete bit rates and transmitted symbol energies in all channels. The thesis develops the calculation methods of the two parameters for interference-free and interference-present channels, respectively. For the interference-present channels, the performance of two-group allocation can be further enhanced by applying a clustering-based channel removal scheme. In order to make the two-group approach more time-efficient, reduction in matrix inversions in optimum energy calculation is then discussed. When the Minimum Mean Square Error (MMSE) equalizer is applied, optimum energy allocation can be calculated by iterating a set of eigenvalues and eigenvectors. By using the MMSE Successive Interference Cancellation (SIC) receiver, the optimum energies are calculated recursively combined with an optimum channel ordering scheme for enhancement in both system performance and time efficiency. This thesis then studies the signature optimization methods with multipath channel and examines their system performances when combined with different resource allocation methods. Two multipath-aware signature optimization methods are developed by applying iterative optimization techniques, for the system using MMSE equalizer and MMSE precoder respectively. A PAM system using complex signature sequences is also examined for improving resource utilization efficiency, where two receiving schemes are proposed to fully take advantage of PAM features. In addition by applying a short chip sampling window, a Singular Value Decomposition (SVD) based interference-free signature design method is presented.
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Bishop, Rachel Ann 1957. "Incentive schemes, moral hazard, and risk aversion: Intrafirm resource allocation and determinants of budgetary slack." Diss., The University of Arizona, 1991. http://hdl.handle.net/10150/289252.
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The existence of private information regarding expected productivity requires decentralized firms to develop intrafirm resource allocation mechanisms. Participation can help central management acquire and allocate resources according to divisional requirements. However, optimal plans require accurate pre-allocation communications. When preferences regarding local objectives, risk, and resources diverge, division managers may bias communications, creating budgetary slack. This study tested the effectiveness of unit-profit + penalty, firm-profit-sharing, and Groves incentive schemes in inducing truthful communication and controlling resource consumption under uncertainty. The experiment incorporated three independent variables: incentive scheme and utility for resource consumption were manipulated between-subjects; risk neutrality and risk aversion were induced within-subject. Three main results are presented. First, contrary to predictions, subjects do not misrepresent expected productivity more under risk aversion, regardless of scheme. Lack of support could be due to limited understanding regarding the experimental task and tradeoffs. The properties of the Groves scheme lead to an insufficient spread among its theoretical predictions, restricting the misrepresentation range and minimizing opportunities to observe differences. Second, both Groves and firm-profit-sharing groups consumed more resources than the unit-profit + penalty groups. Third, subjects in all groups exhibit significant increases in resource consumption under risk aversion. Increased consumption under risk aversion was predicted for both the Groves and firm-profit-sharing groups. However, decreased consumption was hypothesized for the unit-profit + penalty group. To contend with a difficult task under risk aversion and to increase the probability of winning when feedback indicated a low overall likelihood, subjects may have responded with "overconsumption strategies." Overall findings suggest that, although a unit-profit + penalty scheme does not appear to control misrepresentation better than either Groves or firm-profit-sharing schemes, it is more effective in controlling resource consumption. However, its effectiveness in controlling consumption diminishes with risk aversion.
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Nguyen, Tien M., Hung H. Nguyen, James Yoh, Dean J. Sklar, and Thomas Eng. "BANDWIDTH EFFICIENT MODULATION SCHEMES FOR FUTURE TT&C APPLICATIONS." International Foundation for Telemetering, 2001. http://hdl.handle.net/10150/607603.
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International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, NevadaThis paper presents initial results of an investigation on bandwidth efficient waveforms for telemetry, tracking and commands (TT&C). Included in the investigation are waveforms that are currently being considered by the International Consultative Committee for Space Data Systems (CCSDS) and American Institute of Aeronautics and Astronautics (AIAA) for standards, advanced waveforms and others that have the potential to become future standards. The goal of this investigation is to recommend a suite of bandwidth efficient modulation schemes for further investigation. This suite of modulation scheme should be suitable for various TT&C applications with data rates ranging from a few hundreds Bit Per Second (bps) to a few hundreds Mega bps (Mbps). First, the philosophy of waveform evaluation is described. The description includes a list of waveform attributes leading to quantitative and qualitative figures of merit for bandwidth efficient waveforms. Then quantitative results for the two most important waveform attributes (bandwidth efficiency and bit error rate performance) are presented. These results will be used by a follow-on study to significantly reduce the number of candidate waveforms, so that all attributes can be more thoroughly evaluated.
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Pöschl, Felix. "The Potential Effects of Market-based Slot Allocation Schemes on Airline Networks in the European Union." Institut für Transportwirtschaft und Logistik, WU Vienna University of Economics and Business, 2006. http://epub.wu.ac.at/410/1/document.pdf.
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Mathur, Tushar. "STUDY OF SPECTRUM ALLOCATION SCHEMES IN GENERALIZED MULTI PROTOCOL LABEL SWITCHED CONTROL PLANE ENABLED FLEXI GRID NETWORKS." Miami University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=miami1438339701.
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Ruby, Rukhsana. "Uplink scheduling and resource allocation schemes for LTE-advanced systems that incorporate relays or carry heterogeneous traffic." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/54776.
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Scheduling and resource allocation is one of the important tasks of the radio resource management layer in long term evolution (LTE) and LTE-Advanced wireless systems. Uplink scheduling and resource allocation is considered more challenging compared to the downlink case because of individual users' power constraints and the discrete nature of spectrum assignment. Downlink scheduling and resource allocation has extensively been studied for relay equipped or heterogeneous traffic networks, but less work has been considered for the LTE uplink case. In this thesis, we have proposed a few uplink scheduling and resource allocation schemes of LTE-Advanced systems that incorporate relay(s) or carry heterogeneous traffic. First, we have proposed a basic uplink scheduling and resource allocation scheme for decode-and-forward relay aided systems. Existing uplink scheduling works have looked at the problem from different angles instead of basic scheduling and resource allocation. In addition of having optimal resource allocation, the proposed scheme is adaptive. If the system has some bad or redundant relays, the proposed scheme can detect and recommends them to be deactivated. Having observed the difficulty in deciding which users to serve for a relay under the constraint of limited power, second, we have proposed a joint source and relay power allocation scheme for an amplify-and-forward relayed system. Existing works of this problem have ignored one term in their problem formulation, and hence failed to offer the optimal solution for all possible scenarios. We have taken care of that missing term in our work, and have shown the performance improvement comparing with the existing works. In this solution, all entities in the network work in an altruistic manner towards maximizing the network capacity. However, in the real world, the nodes may want some benefits while sacrificing their resource. To model the selfish behavior of the nodes, in the third work, we have proposed a game theoretical solution of this problem. Fourth, we have proposed an uplink scheduling and resource allocation scheme for a network which carries heterogeneous traffic. Although there are some existing uplink scheduling works dealing QoS in heterogeneous traffic networks, those were not careful about detailed standard specific all constraints. In addition to meet the conflicting requirements of QoS for different traffic, the proposed scheme takes the resource utilization constraint into account which is designed to benefit the network operators.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
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Muhammad, Usman Rehan. "Probabilistic and Risk Analysis ofChannel Allocation Schemes,based on Markov Chain Model,used for Next Generation Networks." Thesis, KTH, Tillämpad maskinteknik (KTH Södertälje), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-143956.
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Zabanoot, Zaid Ahmed Said. "Modelling and Analysis of Resource Management Schemes in Wireless Networks. Analytical Models and Performance Evaluation of Handoff Schemes and Resource Re-Allocation in Homogeneous and Heterogeneous Wireless Cellular Networks." Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5383.
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Over recent years, wireless communication systems have been experiencing a dramatic and continuous growth in the number of subscribers, thus placing extra demands on system capacity. At the same time, keeping Quality of Service (QoS) at an acceptable level is a critical concern and a challenge to the wireless network designer. In this sense, performance analysis must be the first step in designing or improving a network. Thus, powerful mathematical tools for analysing most of the performance metrics in the network are required. A good modelling and analysis of the wireless cellular networks will lead to a high level of QoS. In this thesis, different analytical models of various handoff schemes and resource re-allocation in homogeneous and heterogeneous wireless cellular networks are developed and investigated. The sustained increase in users and the request for advanced services are some of the key motivations for considering the designing of Hierarchical Cellular Networks (HCN). In this type of system, calls can be blocked in a microcell flow over to an overlay macrocell. Microcells in the HCN can be replaced by WLANs as this can provide high bandwidth and its users have limited mobility features. Efficient sharing of resources between wireless cellular networks and WLANs will improve the capacity as well as QoS metrics. This thesis first presents an analytical model for priority handoff mechanisms, where new calls and handoff calls are captured by two different traffic arrival processes, respectively. Using this analytical model, the optimised number of channels assigned to II handover calls, with the aim of minimising the drop probability under given network scenarios, has been investigated. Also, an analytical model of a network containing two cells has been developed to measure the different performance parameters for each of the cells in the network, as well as altogether as one network system. Secondly, a new solution is proposed to manage the bandwidth and re-allocate it in a proper way to maintain the QoS for all types of calls. Thirdly, performance models for microcells and macrocells in hierarchical cellular networks have been developed by using a combination of different handoff schemes. Finally, the microcell in HCN is replaced by WLANs and a prioritised vertical handoff scheme in an integrated UMTS/WLAN network has been developed. Simulation experiments have been conducted to validate the accuracy of these analytical models. The models have then been used to investigate the performance of the networks under different scenarios.
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Longin, Carl Friedrich Horst. "Optimum allocation of test resources and comparison of alternative breeding schemes for hybrid maize breeding with doubled haploids." [S.l. : s.n.], 2007. http://nbn-resolving.de/urn:nbn:de:bsz:100-opus-2061.
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Montané, Francesc, Andrew M. Fox, Avelino F. Arellano, Natasha MacBean, M. Ross Alexander, Alex Dye, Daniel A. Bishop, et al. "Evaluating the effect of alternative carbon allocation schemes in a land surface model (CLM4.5) on carbon fluxes, pools, and turnover in temperate forests." COPERNICUS GESELLSCHAFT MBH, 2017. http://hdl.handle.net/10150/625988.
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How carbon (C) is allocated to different plant tissues (leaves, stem, and roots) determines how long C remains in plant biomass and thus remains a central challenge for understanding the global C cycle. We used a diverse set of observations (AmeriFlux eddy covariance tower observations, biomass estimates from tree-ring data, and leaf area index (LAI) measurements) to compare C fluxes, pools, and LAI data with those predicted by a land surface model (LSM), the Community Land Model (CLM4.5). We ran CLM4.5 for nine temperate (including evergreen and deciduous) forests in North America between 1980 and 2013 using four different C allocation schemes:i. dynamic C allocation scheme (named "D-CLM4.5") with one dynamic allometric parameter, which allocates C to the stem and leaves to vary in time as a function of annual net primary production (NPP);
ii. an alternative dynamic C allocation scheme (named "D-Litton"), where, similar to (i), C allocation is a dynamic function of annual NPP, but unlike (i) includes two dynamic allometric parameters involving allocation to leaves, stem, and coarse roots;
iii.–iv. a fixed C allocation scheme with two variants, one representative of observations in evergreen (named "F-Evergreen") and the other of observations in deciduous forests (named "F-Deciduous").
D-CLM4.5 generally overestimated gross primary production (GPP) and ecosystem respiration, and underestimated net ecosystem exchange (NEE). In D-CLM4.5, initial aboveground biomass in 1980 was largely overestimated (between 10 527 and 12 897 g C m−2) for deciduous forests, whereas aboveground biomass accumulation through time (between 1980 and 2011) was highly underestimated (between 1222 and 7557 g C m−2) for both evergreen and deciduous sites due to a lower stem turnover rate in the sites than the one used in the model. D-CLM4.5 overestimated LAI in both evergreen and deciduous sites because the leaf C–LAI relationship in the model did not match the observed leaf C–LAI relationship at our sites. Although the four C allocation schemes gave similar results for aggregated C fluxes, they translated to important differences in long-term aboveground biomass accumulation and aboveground NPP. For deciduous forests, D-Litton gave more realistic Cstem ∕ Cleaf ratios and strongly reduced the overestimation of initial aboveground biomass and aboveground NPP for deciduous forests by D-CLM4.5. We identified key structural and parameterization deficits that need refinement to improve the accuracy of LSMs in the near future. These include changing how C is allocated in fixed and dynamic schemes based on data from current forest syntheses and different parameterization of allocation schemes for different forest types.
Our results highlight the utility of using measurements of aboveground biomass to evaluate and constrain the C allocation scheme in LSMs, and suggest that stem turnover is overestimated by CLM4.5 for these AmeriFlux sites. Understanding the controls of turnover will be critical to improving long-term C processes in LSMs.
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Richards, J. D. W. "The allocation and effects of special employment measures : The case of the temporary employment subsidy and schemes operated by the Department of Industry." Thesis, University of Kent, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.353817.
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Teillard, d'Eyry Félix. "Reconciling food production and biodiversity in farmlands : the role of agricultural intensity and its spatial allocation." Phd thesis, Université René Descartes - Paris V, 2012. http://tel.archives-ouvertes.fr/tel-00766882.
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During the past several decades, agricultural intensification has been crucial to increase the food supply. Several processes related to intensification are very detrimental to the environment, particularly biodiversity. Today, agriculture is facing the challenge of satisfying its demand for food while improving its environmental sustainability. Knowledge of the shape of the relationship between biodiversity and intensity is necessary to determine both where conservation policies will be most effective and how to allocate intensity to reconcile production and biodiversity. Few empirical studies on this relationship exist, and the influence of the spatial arrangement of intensity on biodiversity remains untested. This Ph.D. thesis determined how to target both agricultural intensity and its spatial allocation for meeting production and conservation objectives of farmlands. To answer this research question, we used a country-scaled approach that combined two France-scaled databases that describe agriculture and farmland birds. We characterized a nationwide gradient of agricultural intensity and studied a farmland bird community along this gradient, using several trait-based descriptors (specialization, trophic level, and species main habitat). Agricultural intensity and bird communities were described at the Small Agricultural Region (SAR; mean width = 22.4 km) level. As a first step, we developed a novel method to estimate an intensity indicator that was based on Input Costs/ha, with SAR resolution. This indicator provides a continuous intensity measure that is relevant across different types of agricultural systems. Secondly, we investigated the effects of a gradient of land uses (grassland to arable land) and its heterogeneity on the bird community. We found habitat specialists suffered from habitat loss, while generalists benefited from heterogeneity. Thirdly, we showed that the community responded significantly to intensity, with winner species replacing loser species along the gradient. The shift between losers and winners was sharper at low intensities. Interestingly, spatial aggregation of intensity had a strengthening effect on the bird community. Finally, the relationships linking intensity to the bird community, food production, and economic performance were integrated into a model aimed at optimizing intensity allocation. Optimal allocations reached win-no-lose solutions with the three criteria. They corresponded to targeted intensity modifications: many small changed, favoring homogeneous, extensive clusters, were optimal within an extensification scenario; while a few large changes, favoring heterogeneity, were optimal within an intensification scenario. We provide one of the first studies demonstrating that spatial aggregation of intensity can influence the biodiversity/intensity relationship. Our results also provide an opportunity to improve the effectiveness of conservation policies, at national scales, with spatial targeting: opposite targeting should be performed either to maximize biodiversity benefits or to increase production, while mitigating biodiversity impacts. Our results highlight the importance of mixed allocation strategies between land sparing/sharing extremes. In order to put these opportunities into effect, further research should address the technical solutions that achieve intensity modification at the farm level and design targeted policies that benefit biodiversity and other environmental criteria
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Bousia, Alexandra. "Design of energy efficient network planning schemes for LTE-based cellular networks." Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/386393.
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The rapid expansion of mobile services and the emerging demand for multimedia applications have led to an impressive traffic growth. To this end, Mobile Network Operators (MNOs) seek to extend their infrastructure by installing more Base Stations (BSs), in an effort to increase the network capacity and meet the pressing traffic demands. Furthermore, to fulfill the escalated demands, Heterogeneous Networks (HetNets), which consist of Small Cells (SCs) and the traditional BSs, constitute the new trend of next generation networks.
The deployed infrastructure implies a rise in the Capital Expenditures and has a direct impact on the network energy consumption, thus resulting in higher Operational Expenditures. Hence, the investigation of energy efficient solutions will bring down the energy consumption and the network cost. Since the BS is the most power hungry component, the research community has shifted towards the investigation of BS deactivation schemes. These schemes propose that part of the infrastructure can be temporarily switched off, when the traffic is low, while the active BSs extend their coverage to serve the network.
Based on a comprehensive review of the state-of-the-art, a set of research opportunities were identified. This thesis provides contributions to the field of BS switching off strategies for wireless macro BSs networks and HetNets of single and multiple MNOs by proposing mechanisms that enhance different aspects of the network performance. The BSs deactivation, the innovative trend of infrastructure sharing and the financially driven collaboration among the involved parties of the current and future networks promise significant improvements in terms of energy and cost savings. The main thesis contributions are divided into three parts, described next.
The first part of the thesis introduces innovative BS switching off approaches in single-operator environments, where only macro BSs are deployed. The proposed strategies exploit the inherit characteristics of the traffic load pattern (e.g., distribution of the users, traffic volume, etc.) and the distinctive features of the wireless cellular networks (e.g., BSs position, topology, etc.). Theoretical analysis and computer-based simulations show the performance improvement offered by the switching off strategies with respect to energy efficiency.
The second part of the thesis explores a different challenge in network planning. The coexistence of multiple MNOs in the same geographical area has motivated a new business model, known as infrastructure sharing. A roaming-based deactivation scheme is proposed, by taking into account the rationality and the conflicting interests of the MNOs. The proposed game theoretic framework enables the MNOs to take individual switching off decisions, thus bypassing potential complicated agreements. The theoretical and simulation results show that our proposal significantly improves the energy efficiency, guaranteeing at the same time the throughput in realistic scenarios. Moreover, the proposed scheme provides higher cost efficiency and fairness compared to the state-of-the-art algorithms, motivating the MNOs to adopt game theoretic strategies.
The third part of the thesis focuses on the exploitation of HetNets and the proposal of energy and cost effective strategies in SC networks with multiple MNOs. We effectively address the cost sharing by proposing accurate cost models for the SCs to share the network cost. Taking into account the impact of the traffic on the cost, we propose novel cost sharing policies that provide a fair outcome. In continuation, innovative auction-based schemes within multiobjective optimization framework are introduced for data offloading from the BSs, owned by the MNOs, to the third-party SC networks. The proposed solution captures the conflicting interests of the MNOs and the third-party companies and the obtained results show that the benefit of proposing switching off approaches for HetNets.La rápida expansión de los servicios móviles y de la demanda emergente de aplicaciones multimedia han dado lugar a un impresionante crecimiento del tráfico. Operadores de redes móviles (MNOs) tratará de extender su infraestructura mediante la instalación de más estaciones base (BSs), en un esfuerzo por aumentar la capacidad de la red y satisfacer las apremiantes demandas de tráfico. Además, para cumplir con las exigencias escalada, redes heterogéneas (HetNets), constituyen la nueva tendencia de las redes de próxima generación. La infraestructura implica un aumento en los gastos de capital y tiene un impacto directo en el consumo de energía a la red, lo que resulta en un aumento de los gastos operacionales. La investigación de soluciones de eficiencia energética hará bajar el consumo de energía y el coste de la red. La comunidad científica se ha desplazado hacia la investigación de los sistemas de desactivación de BSs. Estos esquemas proponen que parte de la infraestructura se puede cdesectivarse, cuando el tráfico es bajo, mientras que los BSs activas extender su cobertura al servicio de la red. Esta tesis ofrece contribuciones al campo de la BSs desconexión para las redes y HetNets con uno o multiples MNOs, proponiendo mecanismos que mejoran diferentes aspectos del rendimiento de la red. La desactivación de BS,s la tendencia innovadora de compartir infraestructura y la colaboración impulsada financieramente entre las partes implicadas de las redes actuales y futuras prometen mejoras significativas en términos de ahorro energético y económico. Las principales contribuciones de tesis se dividen en tres partes, que se describen a continuación. La primera parte de la tesis introduce innovadora apagar enfoques en entornos de un solo operador, donde se despliegan sólo macro BSs. Las estrategias propuestas explotan las características de tráfico (por ejemplo, la distribución de los usuarios, el volumen de tráfico, etc.) y las características distintivas de las redes (por ejemplo, la posición BS, topología, etc.). Análisis teórico y simulaciones muestran la mejora del rendimiento ofrecido por las estrategias de conmutación con respecto a la eficiencia energética. La segunda parte de la tesis explora un reto diferente en la planificación de la red. La coexistencia de múltiples operadores en la misma zona geográfica ha motivado un nuevo modelo de negocio, conocida como la compartición de infraestructura. Se propone un esquema de desactivación basada en itinerancia, teniendo en cuenta la racionalidad y los intereses en conflicto de los operadores de redes móviles. Los resultados teóricos y de simulación muestran que nuestra propuesta mejora significativamente la eficiencia energética, garantizando al mismo tiempo el rendimiento en escenarios realistas. Por otra parte, el esquema propuesto proporciona una mayor eficiencia de costes y la equidad en comparación con los algoritmos del estado de la técnica, motivar al mnos de adoptar estrategias de teoría de juegos. La tercera parte de la tesis se centra en la explotación de HetNets y la propuesta de estrategias eficaces de energía y costes en las redes con múltiples operadores. Nos dirigimos efectivamente la participación en los costos, proponiendo modelos de costos precisos para para compartir el costo de la red. Teniendo en cuenta el impacto del tráfico en el coste, proponemos políticas costos compartidos novedosas que proporcionan un resultado justo. En la continuación, los esquemas basados en subastas innovadoras dentro de marco de optimización multiobjetivo se introducen los datos que descargan de la BS. La solución propuesta recoge los intereses en conflicto de los operadores de redes móviles y las compañías de terceros y los resultados obtenidos muestran que el beneficio de proponer la desconexión se acerca para HetNets
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Uznanski, Przemyslaw. "Large scale platform : Instantiable models and algorithmic design of communication schemes." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-00878837.
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The increasing popularity of Internet bandwidth-intensive applications prompts us to consider followingproblem: How to compute efficient collective communication schemes on large-scale platform?The issue of designing a collective communication in the context of a large scale distributed networkis a difficult and a multi-level problem. A lot of solutions have been extensively studied andproposed. But a new, comprehensive and systematic approach is required, that combines networkmodels and algorithmic design of solutions.In this work we advocate the use of models that are able to capture real-life network behavior,but also are simple enough that a mathematical analysis of their properties and the design of optimalalgorithms is achievable.First, we consider the problem of the measuring available bandwidth for a given point-topointconnection. We discuss how to obtain reliable datasets of bandwidth measurements usingPlanetLab platform, and we provide our own datasets together with the distributed software usedto obtain it. While those datasets are not a part of our model per se, they are necessary whenevaluating the performance of various network algorithms. Such datasets are common for latencyrelatedproblems, but very rare when dealing with bandwidth-related ones.Then, we advocate for a model that tries to accurately capture the capabilities of a network,named LastMile model. This model assumes that essentially the congestion happens at the edgesconnecting machines to the wide Internet. It has a natural consequence in a bandwidth predictionalgorithm based on this model. Using datasets described earlier, we prove that this algorithm is ableto predict with an accuracy comparable to best known network prediction algorithm (DistributedMatrix Factorization) available bandwidth between two given nodes. While we were unable toimprove upon DMF algorithm in the field of point-to-point prediction, we show that our algorithmhas a clear advantage coming from its simplicity, i.e. it naturally extends to the network predictionsunder congestion scenario (multiple connections sharing a bandwidth over a single link). We areactually able to show, using PlanetLab datasets, that LastMile prediction is better in such scenarios.In the third chapter, we propose new algorithms for solving the large scale broadcast problem.We assume that the network is modeled by the LastMile model. We show that under thisassumption, we are able to provide algorithms with provable, strong approximation ratios. Takingadvantage of the simplicity and elasticity of the model, we can even extend it, so that it captures theidea of connectivity artifacts, in our case firewalls preventing some nodes to communicate directlybetween each other. In the extended case we are also able to provide approximation algorithmswith provable performance.The chapters 1 to 3 form three successful steps of our program to develop from scratch amathematical network communication model, prove it experimentally, and show that it can beapplied to develop algorithms solving hard problems related to design of communication schemesin networks.In the chapter 4 we show how under different network cost models, using some simplifyingassumptions on the structure of network and queries, one can design very efficient communicationschemes using simple combinatorial techniques. This work is complementary to the previous chapter in the sense that previously when designing communication schemes, we assumed atomicityof connections, i.e. that we have no control over routing of simple connections. In chapter 4 weshow how to solve the problem of an efficient routing of network request, given that we know thetopology of the network. It shows the importance of instantiating the parameters and the structureof the network in the context of designing efficient communication schemes.
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Soares, Mariana Flor Eiras. "UK pension funds : fund portfolio performance analysis." Master's thesis, Instituto Superior de Economia e Gestão, 2020. http://hdl.handle.net/10400.5/20707.
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Mestrado em Mathematical FinanceNo UK, indivíduos recebem uma pensão após a reforma, ou se falecer sua/seu esposa/o. Esta pode ser oferecida pelo estado, mas um dos casos mais comuns é; as pessoas recebem-na do seu fundo de pensão ocupacional (derivado do seu caminho de trabalho). Este tipo de pensão é fornecido pelo empregador e acumula benefícios que irão gerar o salário do empregado após a reforma. Para financiar as pensões, os empregadores devem criar um portfólio de investimento, que inclui diversos fundos e classes de ativos (alguns que pretendem gerar maiores retornos, assumindo maiores riscos, e outros que pretendem gerar retornos seguros, mas mais baixos). De modo a monitorizar o desempenho destes fundos, com o fim de entender se está a ser feita uma gestão adequada dos mesmos, é necessário ter em conta os seguintes fatores: gestão de risco, alocação dentro das diferentes classes de fundos e seleção de fundos. Para este efeito é utilizado o método de analise de atribuição, que nos diz o valor que foi adicionado ao portfolio proveniente das decisões do gestor. No atual período de pandemia, que afetou os mercados financeiros de forma considerável, o estudo desenvolvido neste projeto, visa perceber qual foi o impacto desta situação em quatro portfolios diferentes, com diferentes estratégias de investimento, e maioritariamente estudar as diferentes posições que foram assumidas pelos diferentes gestores, com o objetivo de manter a estabilidade do desempenho dos portfolios depois da grande queda dos mercados que se deu com o fecho da economia no inicio de 2020.
In the UK, individuals receive a pension after their retirement or their spouse's death. This pension can be provided by the state, but one of the most common cases is that people will receive it from their occupational pension fund (in result of their work path). This type of pension is sponsored by the employer and it accumulates benefits that will generate the income of a person after their retirement. To fund the pensions of the employees, employers need to create investment portfolios, that include different funds and asset classes (some seek higher growth while assuming higher risk, and others seek guaranteed, but lower returns). To monitor the performance of these portfolios and understand if the management is being done efficiently, one needs to take into consideration: risk management, asset allocation and selection decisions. For this effect, we use the attribution analysis method, which tells us the value that has been added to the portfolio by the active management decisions. In a period of pandemic, that affected the financial markets considerably, the study practiced in this project, aims to understand what was the impact of the situation in four different portfolios, with different investment strategies, and mainly to study the different positions that were assumed by the different managers, in order to keep the portfolios stability after the rough market crash that came with the economic shutdown in the beginning of 2020.
info:eu-repo/semantics/publishedVersion
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Dong, Xuefeng. "Efficient schemes for channel allocations in mobile cellular networks /." The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487942739808166.
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Chingchit, Soontorn. "Design and performance evaluation of a flexible clustering and allocation scheme for parallel processing." Thesis, Curtin University, 1999. http://hdl.handle.net/20.500.11937/240.
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Parallel processing is an important and popular aspect of computing and has been developed to meet the demands of high-performance computing applications. In terms of hardware, a large number of processors connected with high speed networks are put together to solve large scale computationally intensive applications. The computer performance improvements made so far have been based on technological developments. In terms of software, many algorithms are developed for application problem execution on parallel systems to achieve required performance. Clustering and scheduling of tasks for parallel implementation is a well researched problem. Several techniques have been studied to improve performance and reduce problem execution times. In this thesis, a new clustering and scheduling scheme, called flexible clustering and scheduling (FCS) algorithm is proposed. It is a novel approach where clustering and scheduling of tasks can be tuned to achieve maximal speedup or efficiency. The proposed scheme is based on the relation between the costs of computation and communication of task clusters. Vital system parameters such as processor speed, number of processors, and communication bandwidth affect speedup and efficiency. Processor speed and communication bandwidth vary from system to system. Most clustering and scheduling strategies do not take into account the system parameters. The low complexity FCS algorithm can adapt itself to suit different parallel computing platforms and it can also be tuned to suit bounded or unbounded number of processors. The analytical, simulation and experimental studies presented in this thesis validate the claims.
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Xing, Zitong. "A dynamic radio channel allocation scheme for WLANs." Diss., Online access via UMI:, 2005.
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Wright, Ian Douglas. "A stochastic approach to pension scheme funding and asset allocation." Thesis, Heriot-Watt University, 1997. http://hdl.handle.net/10399/1282.
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Chang, Cooper, and 張古博. "Resource Allocation Schemes for Cellular Communication Systems." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/70069013623758633946.
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博士國立交通大學
電信工程系
87
Designing resource allocation schemes for cellular systems is one of important engineering issues for improving spectrum efficiency, because of tremendous growth of the mobile user population. In this dissertation, we study resource allocation schemes, including hierarchical cellular structure, priority strategies, duplexing scheme, and multiplexing/multiple access mechanism, for cellular communications systems. We first analyze a hierarchical cellular system with priority channel assignment schemes. Hierarchical cellular systems are designed to take the advantages of both microcell and macrocell systems. The effects of queueing schemes for new and handoff calls and guard channel scheme for handoff calls on the system performance are studied. And then, allocation schemes of duplexing scheme and multiplexing/multiple access mechanism are studied. Variable partition duplex scheme, which is designed to take the advantages of the nature of conversation activity, is proposed on packet reservation multiple access (PRMA). Enlarged reservation duration scheme is proposed to improve the PRMA system. Finally, we study the effects of ways to share the communication resource on the performance of CDMA/TDD systems in terms of outage probability and blocking probability. Dynamic and fixed allocated schemes are proposed for CDMA/TDD, and then their system performances are compaired and analyzed. We successfully analyze the above resource allocation schemes and verify the validity of these analyses by simulations. The numerical results show that our proposed resource allocation scuhemes indeed have some improvement on the performance of cellular communication systems.
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Haciomeroğlu, Fatih. "On-line measurement-based capacity allocation schemes." 2003. http://www.lib.ncsu.edu/theses/available/etd-03262003-223315/unrestricted/etd.pdf.
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CHEN, CHI-CHUNG, and 陳起忠. "Efficient Radio Resource Allocation Schemes in Wireless Networks." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/8wcrns.
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博士國防大學理工學院
國防科學研究所
106
As the wireless communications is developing, the numbers of wireless user are also increasing rapidly, the bandwidth of networks is inefficiency. There are many reson of causing the inefficiency channel. Such as the execlusive right of users, channel idle when low traffic load, the numbers of user are increasing, user competed the channel resource, and channel traffic load. In order to improve channel utilization. In this Thesis, we propose two schemes for allocating resourecs in wireless communications. The first scheme is an easy and efficient channel assignment scheme based on the theory of finite projective plane (FPP). Since the bandwidth resources of wireless communications are scarce and limited due to the large number of user requirements. The aim of the proposed scheme is to improve channel utilization. Differing from the conventional assignment by assigning one channel per user, the proposed scheme allocates multiple channels for each user assignment, i.e. each user possesses multiple transmit channels corresponding to the point numbers of a set of FPP. The arrangements of intermixed grouping style of channels based on FPP also provide fairness among users. In the first scheme, the channel assignment schemes are also analyzed and compared with each other through Markov chain modeling. The channel assignment efficiency with our defined effective puncture through ratio is obviously enhanced from simulation results with the proposed FPP scheme, especially when the offered traffic load is light. The secend scheme is a novel grouping slotted aloha scheme. Slotted Aloha (SA) is a conventional distributed contention-based scheme in which the link time is divided into slots of equal duration and the users contend to access by transmitting with a predefined slot-access probability. Due to various applications and developments in wireless communications and networks, SA random access scheme and its various variants have gained renewed interests recently. In thesis, we propose a novel grouping slotted aloha(GSA) scheme with different grouping arrangements and (or) variable transmit probabilities (VTP) to improve throughput performance and achieve fairness among all user nodes. It shows improvements of throughput available with the proposed scheme by simply grouping user nodes and mapping VTPs onto the grouped slot positions for various wireless communications.
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Peng, I.-Hsuan, and 彭亦暄. "Study of Effective Resource Allocation Schemes in WDM Networks." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/pmjacx.
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博士國立中央大學
通訊工程研究所
96
In this dissertation, we focus on the following WDM network related issues. The first is the wavelength assignment algorithm of multicast traffic; the second is the routing scheme of lightpath with guaranteed protection switching time; and the third is the construction of hierarchical WDM topology. In the first issue, we assume the WDM network to be with sparse wavelength conversion nodes (SWCN) and a systematic approach for the assignment of wavelength in networks is proposed. Based on the MWA-SWC scheme, a multicast tree is divided into groups based on common wavelengths so that the wavelength can be assigned effectively. The simulation results show that the proposed scheme demonstrates much better performance than that of the SCG scheme, in which we extended the original to be applicable for SWCN network. We also found that the performance is not always improved proportionally to the increment of the wavelength conversion nodes. The improvement reaches saturation when the number of conversion nodes is above 35% of the total number of nodes. In order to minimize the influence on transmission quality caused by the failure of link and to provide a definite time for the recovery from the failure in optical network, the protection switching time (PST) should be taken into consideration during path arrangement. The PST-guaranteed scheme, which is based on the concept of short leap shared protection (SLSP), for the arrangement of data paths in WDM network is proposed and studied. The proposed scheme provides an efficient procedure to determine a just-enough PST-guaranteed backup paths for a working path. In addition, the network cost is also considered in a heuristic manner and the simulation results illustrate that the required cost of the selected path in the proposed scheme is competitive with which of the shared path scheme. In the third issue, a systematic approach is proposed to construct the hierarchical topology in a heuristic manner so that the network resource can be effectively utilized. The proposed scheme groups nodes into logical routing area (LRA) by considering the appropriate group size and the degree of each WDM node. Simulation results demonstrate that the performance of the proposed scheme is superior to that of the evenly grouped scheme. The integration of wired backbone and wireless access network is recognized to be the trend of next generation network. In this dissertation, we also survey the possible integration architectures of WiMax and EPON networks to seek for potential research topics as our future works.
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Tai, Yu-Fen, and 戴郁芬. "Dynamic Channel Allocation Schemes for IEEE 802.11 Wireless LAN." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/16667501806931282462.
Full textAbstract:
碩士國立交通大學
資訊工程系所
93
With the rapid evolution of wireless technology, WLAN gradually becomes a common solution of setting up a local area network. In order to cover the whole building with wireless signals, the network administrators often choose to deploy the access points (APs) densely. On the other hand, under the IEEE 802.11 infrastructure mode, there may be interference between the nearby access points if they use the same channel. Static channel assignment is not good enough because of the limitation of channels and the mobility of users. How to change the channels of access points dynamically to speed up the throughput of the whole network is the main issue that we want to discuss. In this thesis, we propose two centralized schemes to assign the channels of access points dynamically according to the AP utilizations. We also implement one of our schemes and compare the performance of it with other methods by experiments. The experiment result shows that our methods indeed increase the network throughput a lot and achieve better performance than others.
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DLAMIN, THEMBELIHLE, and 狄天柏. "Clustering and Resource Allocation Schemes for Hybrid Femtocell Networks." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/27207044722567235666.
Full textAbstract:
碩士國立交通大學
電機資訊國際學程
102
為了提升住宅和企業內部環境的服務範圍和服務品質，毫微微型細胞 (femtocells)已被視為一個解決方案，因為它可以提供低功率耗損且讓使用者自行佈署的特性。此外，毫微微型細胞可以被允許與巨細胞網路 (macro network)使用相同的載波頻率或是不同的載波頻率。在一個具有高緻密毫微微型細胞佈署的傳輸環境中，資源配置和干擾管理是一個重要的研究議題，其中干擾主要來自於使用不同的存取模式的毫微微型細胞。若毫微微型細胞運作在封閉存取模式 (closed access mode)指的是只允許擁有子載波使用權的使用者來和毫微微型細胞做連結;而在開放存取模式 (open access mode)指的是所有使用者皆可和毫微微型細胞來做連結。 為了獲得毫微微型細胞在企業內部環境建置的好處，混合式存取模式 (hybrid access mode)可以考慮被系統所採用，該模式可以同時服務封閉式用戶群組 (closed subscriber group)毫微微型細胞內的使用者和非封閉式用戶群組(Non-closed subscriber group)毫微微型細胞內的使用者。此外，當毫微微型細胞運作在混合式存取模式，可以提供封閉和非封閉式使用者間不同的服務層級。 在本論文中，我們考慮毫微微型細胞運作在混合式存取模式，且僅允許非封閉式使用者使用連結的毫微微型細胞的部分限制資源。為了最大化非封閉式用戶群的上鏈傳輸容量，本論文提出了一種集中式的功率配置方式，為非封閉式用戶群使用者進行資源的分配，其中使用了幾何規劃（geometric programming）和一種新穎的次佳化分群策略。此外，我們也考慮非封閉式使用者允入控制條件 (admission control condition) 的限制。本論文還提出一個在賽局理論架構下的分散式功率配置演算法。其中利用了非合作式的賽局（non-cooperative game）理論及其納什均衡 （Nash equilibrium）的收斂特性。本論文針對在非合作式的賽局中，證明純策略（pure strategy）納什均衡的存在。我們所設計的功率配置演算法主要是根據毫微微型細胞與其服務的用戶之間的距離分配上鏈的功率，以最大化效益函數（utility function）。分析結果顯示，我們提出的資源與分群演算法能夠有效地改善系統的整體效能。
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Shih, Yung-Chien, and 史永健. "Channel Allocation and Authentication Schemes for Wireless Mesh Networks." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/00940706052586723658.
Full textAbstract:
博士國立交通大學
資訊科學與工程研究所
99
While wireless mesh networks (WMNs) are gaining momentum in widespread application, we are concerned with fast handoff in a secure mesh environment. To this end, we present a means in the context of IEEE 802.11s by allowing a mesh portal to act as an IEEE 802.1X authenticator, to reduce costly IEEE 802.1X authentications during handoff. As the mesh portal (MPP) engages in IEEE 802.1X authentication and cryptographic key management, our scheme maintains an end-to-end secure channel between a mobile station and the MPP wherever the station roams in the network. Therefore, without compromising required robust security, IEEE 802.1X authentication can be bypassed during handoff to reduce overall delay in an approach suggested for moderately sized networks. A WMN suffers from a co-channel interference problem when mesh nodes share the same wireless access channels. Therefore, the overall throughput of WMNs may not be able to increase substantially even with broadband physical layer technologies. The problem also causes unexpected transmission delays in the network, which could seriously influence the process of authentications. As a remedy, we propose an end-to-end channel allocation scheme, extending the radio-frequency-slot method and providing stable throughput for end-to-end packet delivery in WMNs. Although separating transmissions of data and acknowledgment packets on two different channels is not our new finding, we observe that the non-overlapping channels can be efficiently reused if the concept is introduced into our scheme. Moreover, by applying link and path metrics for route selection, the end-to-end throughput and delay can be maintained, and the overall throughput of WMNs can be improved. For fast handoff, a mobile station should be able to detect immediately the changes of a network environment, such that the station can perform handoff process at correct time. To this end, we designed and implemented a middleware platform, providing application programming interfaces (APIs) for upper applications to use cross-layer signaling and event notification mechanisms. The applications can configure and acquire status of underlying protocol stack via the cross-layer signaling mechanism, and can immediately detect changes of a network environment via the event notification mechanism.
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Gwo-Ruey, Lee, and 李國瑞. "Performance Evaluation of Subcarrier Allocation Schemes over OFDM Systems." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/51679276737263993659.
Full textAbstract:
碩士國立中正大學
通訊工程研究所
90
After more than thirty years of research and development, Orthogonal Frequency Division Multiplexing (OFDM) stands out conspicuously. Because of its high-speed data transmission and effectiveness in combating the frequency selective fading channel, OFDM technique is widely used in wireless communication nowadays. For the time being, a thorough research on OFDM becomes more essential. In this thesis, the basic principles and simulation of OFDM system are investigated in advance. Then, the researches on subcarrier allocation schemes over OFDM systems are proposed. By leaving out weak subcarriers and applying the subcarrier allocation scheme, the system performance can be guaranteed. However, it will lead to additional errors if the time-variant channel is considered. In digital communication, the error control coding techniques provide a way to improve the system performance. By taking its advantages into account, the subcarrier allocation scheme combined with different error control coding techniques are proposed. In this thesis, we employ the repeat code and linear block code to achieve our goal. The efficiency of these techniques will be demonstrated by simulation results. The proposed methods have better BER performance than original subcarrier allocation scheme.
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Lydeamore, Michael John. "Approximations of stochastic household models for comparing antiviral allocation schemes." Thesis, 2015. http://hdl.handle.net/2440/93524.
Full textAbstract:
From the first recorded influenza pandemic in 1890, there have been new strains of influenza which have caused pandemics approximately every 30 years including recent events such as the H5N1 Avian 'Flu pandemic and the 2009 H1N1 Swine 'Flu pandemic. Although the 2009 pandemic was mild in nature, if events of the past are any indication then control of future pandemics is of utmost importance. Vaccination is commonly looked at to help control the spread of a pandemic, however, vaccinations are strain-specific. While developing a new vaccine is possible, the World Health Organisation estimates that this process would take four to five months. This means that vaccination cannot be used to help control the spread of influenza early on in a pandemic. An alternative are antivirals which are not strain-specific, meaning that they can potentially be used to help control the spread of influenza early on in a pandemic. Antivirals are, however, not as effective at reducing the spread of disease when compared to vaccination. In the 2009 Swine 'Flu pandemic, many countries worldwide utilised antiviral medication, with the aim to assist in controlling the spread of influenza. The most common method in which these antivirals were utilised we refer to as dynamic allocation. In dynamic allocation, when the first person in a household experiences influenza-like symptoms, they report to a health professional. Then, a sample is sent for laboratory testing. If the individual is confirmed to have influenza, the entire household is allocated a course of antivirals and every member of the household begins taking them. The potential weakness in this strategy is the delay between becoming infectious and a household receiving antivirals. We consider an alternative antiviral allocation scheme which we call preallocation. In a preallocation scheme, instead of waiting for antivirals to be delivered after the first confirmed infection, as is the case with dynamic allocation, the antivirals are delivered to households at the beginning of the pandemic. When the first person experiences symptoms, they contact a health professional via a telephone hotline. The professional then decides if it is likely that the individual has influenza. If the individual is likely to have influenza then the entire household starts taking antivirals immediately, just as is the case in dynamic allocation. The advantage of this scheme is that the delay is essentially zero, but there is the potential for the antivirals to be wasted in at least two ways. First, this type of identification of infection is clearly less precise than laboratory testing. Second, it is possible that antivirals will be preallocated to a household who will never experience infection and so those antivirals will essentially be wasted. It is this tradeoff that is the focus of this thesis. The stochastic households epidemic model which is detailed and developed in this work incorporates the household structure of a general population. This allows us to incorporate the stronger mixing of individuals who share a household compared to individuals in the general population, as well as the fact that antivirals are allocated to an entire household when infection is first detected. To analyse this model, we develop two approximations: (i) A branching process approximation, and (ii) a deterministic approximation, that assist us in calculating quantities associated with a pandemic. The branching process is very fast to compute, but due to required assumptions in the derivation, it is only able to describe the early stages of the pandemic. The branching process is able to rapidly compute quantities such as the Malthusian parameter, r, and the household reproductive ratio, R* [* subscript], but is unable to calculate quantities such as the final epidemic size, that is, the total number of people infected over the course of the pandemic.. The deterministic approximation does not allow for as rapid evaluation as the branching process approximation, but is able to approximately reproduce the entire expected pandemic curve, giving access to quantities such as the expected final epidemic size. Both of these approximations are fast to compute so we can explore a range of parameters and compare the two allocation schemes - dynamic allocation and preallocation. We show that preallocation of antivirals often leads to a smaller final epidemic size than dynamic allocation for a severe pandemic outbreak, while a dynamic allocation scheme often gives a lower Malthusian parameter, r, and household reproductive ratio, R* [* subscript]. We provide a justification for this behaviour and demonstrate that the results are relatively robust across the parameters controlling the pandemic. We also consider a number of extensions to the deterministic approximation such as the incorrect use of antivirals, a hybrid allocation scheme, and the production of antivirals during the pandemic. Under these extensions, the general behaviour of the two schemes - preallocation yielding a lower final epidemic size but dynamic allocation yielding superior early-time quantities - is unchanged.Thesis (M.Phil.) -- University of Adelaide, School of Mathematical Sciences, 2015
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張萬邦. "Energy-Efficient Resource Allocation Schemes for Relay-Enhanced OFDMA Networks." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/88807981784080218981.
Full textAbstract:
碩士國立交通大學
電信工程研究所
99
This thesis studies the problem of joint allocation of subchannel, transmission power, and phase duration in the relay-enhanced bidirectional orthogonal frequency-division multiple access (OFDMA) system. The challenges of this resource allocation problem arise from the complication of multiple-phase assignments within a subchannel since the relay station can provide an additional signal path from the base station to the user equipments (UEs). Existing research work does not fully consider all the influential factors to achieve feasible resource allocation for the relay-based networks. Considering the energy consumption is one of principal issues, the energy-efficient resource allocation (EERA) schemes are proposed in this thesis to design the allocation of subchannel, power, and phase duration for the UEs with the consideration of direct and two-hop communications. Both the four-phase and two-phase bidirectional relaying assignments and the network coding technique are considered to obtain the suboptimal solution for the proposed EERA schemes. Different weights are designed for the UEs to achieve the minimization of weighted system energy for the relay-enhanced networks. Simulation results show that the proposed EERA schemes can provide comparably better energy conservation and outage performance with the consideration of quality-of-service support.