Dissertations / Theses on the topic 'Channel model'
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Lee, Hong Seng. "Spatial channel model /." free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p1426081.
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Tan, Bo. "Channel modelling and relay for powerline communications." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/8062.
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The thesis discusses the channel modelling and relay techniques in powerline communications (PLC) which is considered as a promising technology for the Smart Grid communications, Internet access and home area network (HAN). In this thesis, the statistical PLC channel characteristics are investigated, a new statistical channel modelling method is proposed for the in-door PLC. Then a series of the relay protocols are suggested for the broadband communications over power grid. The statistical channel modelling method is proposed to surmount the limits of the traditional deterministic PLC channel models such as multipath model and transmission line model. To develop the channel model, the properties of the multipath magnitudes, interval between the paths, cable loss and the channel classification are investigated in detail. Then, each property is described by statistical distribution or formula. The simulation results show that the statistical model can describe the PLC channels as accurate as deterministic models without the topology information which is a time-consuming work for collecting. The relay transmission is proposed to help PLC adapting the diverse application scenarios. The protocols covers the main relay aspects which include decode/amplify forwarding, single/ multiple relay nodes, full/half duplex relay working mode. The capacity performance of each protocol is given and compared. A series of the facts which improve the performance of the PLC networks are figured out according to simulation results. The facts include that the decode-and-forward is more suitable for the PLC environment, deviation or transforming station is better location for placing relay node and full duplex relay working mode help exploiting the capacity potential of the PLC networks. Some future works are pointed out based on the work of statistical channel model and relay. In the last part of this thesis, an unit based statistical channel model is initialled for adapting various PLC channel conditions, a more practical relay scenario which contains multiple data terminals is proposed for approaching the realistic transmission scenario. At last, the relay for the narrowband PLC Smart Grid is also mentioned as future research topic.
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Jakob, Markus Prüfer. "Compact DC Modelling of Short-Channel Effects in Organic Thin-Film Transistors." Doctoral thesis, Universitat Rovira i Virgili, 2022. http://hdl.handle.net/10803/673905.
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Els transistors orgànics de capa fina (TFT) són dispositius prometedors per a les pantalles flexibles de matriu activa i
els conjunts de sensors, ja que poden fabricar-se a temperatures de procés relativament baixes i, per tant, no sols en
vidre, sinó també en substrats polimèrics. Per a millorar el rendiment dinàmic dels dispositius i circuits TFT , una
reducció agressiva de la longitud de canal provoca efectes extrínsecs en els dispositius que han de ser capturats per
models compactes.
Aquesta tesi presenta models analítics, basats en la física, de la degradació de la pendent subumbral, el roll-off del
voltatge llindar i l'efecte DIBL en TFTs coplanars i escalonats que poden ser implementats en qualsevol model
compacte de corrent continu arbitrari que estigui definit pel voltatge llindar i la pendent subumbral. Per tant, l'equació
diferencial de Laplace es resol per a la geometria coplanar i escalonada aplicant la transformación Schwarz-Cristoffel.
Les solucions del potencial serveixen de base per a la definició de les equacions del model. A més, es desenvolupen
models compactes de les barreres Schottky dependents de la polarització en les interfícies font/semiconductor i
drenador/semiconductor en els TFT coplanars i escalonats, que modelen la injecció i l'ejecció de portadors de càrrega,
respectivament, com a corrent d'emissió termoiònica.Los transistores orgánicos de capa fina (TFT) son dispositivos prometedores para las pantallas flexibles de matriz activa y los conjuntos de sensores, ya que pueden fabricarse a temperaturas de proceso relativamente bajas y, por tanto, no sólo en vidrio, sino también en sustratos poliméricos. Para mejorar el rendimiento dinámico de los dispositivos y circuitos TFT, una reducción agresiva de la longitud de los canales provoca efectos extrínsecos en los dispositivos que tienen que ser capturados por modelos compactos. Esta tesis presenta modelos analíticos, basados en la física, de la degradación de la pendiente subumbral, el roll-off del voltaje umbral y el efecto DIBL en TFTs coplanares y escalonados que pueden ser implementados en cualquier modelo compacto de corriente continua arbitrario que esté definido por el voltaje umbral y la pendiente subumbral. Por lo tanto, la ecuación diferencial de Laplace se resuelve para la geometría coplanar y escalonada aplicando la transformación Schwarz-Christoffel. Las soluciones del potencial sirven de base para la definición de las ecuaciones del modelo. Además, se desarrollan modelos compactos de las barreras Schottky dependientes de la polarización en las interfaces fuente/semiconductor y drenador/semiconductor en los TFT coplanares y escalonados, que modelan la inyección y la eyección de portadores de carga, respectivamente, como corriente de emisión termoiónica
Organic thin-film transistors (TFTs) are promising devices for flexible active-matrix displays and sensor arrays, since they can be fabricated at relatively low process temperatures and thus not only on glass, but also on polymeric substrates. In order to improve the dynamic TFT and circuit performance, an aggressive reduction of the channel length causes extrinsic de-vice effects that have to be captured by compact models. This dissertation presents analytical, physics-based models of the subthreshold-swing degra-dation, the thresholdvoltage roll-off and DIBL effects in coplanar and staggered TFTs that can be implemented in any arbitrary compact dc model that are defined by the threshold voltage and the subthreshold swing. Therefore, Laplace’s differential equation is solved for the coplanar and staggered geometry by applying the Schwarz-Christoffel transformation. The potential solutions serve as a basis for the definition of the model equations. Further-more, compact models of the biasdependent Schottky barriers at the source/semiconductor and drain/semiconductor interfaces in coplanar and staggered TFTs are derived, which model the charge carriers injection and ejection, respectively, as thermionic emission cur-rent. Thereby, in case of the source barrier, the Schottky barrier lowering effect due to im-age charges is captured and therefore, an analytical expression of the electric field at the source barrier is derived.
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Khanal, Sandarva. "Aeronautical Channel Modeling for Packet Network Simulators." International Foundation for Telemetering, 2011. http://hdl.handle.net/10150/595747.
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ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, NevadaThe introduction of network elements into telemetry systems brings a level of complexity that makes performance analysis difficult, if not impossible. Packet simulation is a well understood tool that enables performance prediction for network designs or for operational forecasting. Packet simulators must however be customized to incorporate aeronautical radio channels and other effects unique to the telemetry application. This paper presents a method for developing a Markov Model simulation for aeronautical channels for use in packet network simulators such as OPNET modeler. It shows how the Hidden Markov Model (HMM) and the Markov Model (MM) can be used together to first extract the channel behavior of an OFDM transmission for an aeronautical channel, and then effortlessly replicate the statistical behavior during simulations in OPENT Modeler. Results demonstrate how a simple Markov Model can capture the behavior of very complex combinations of channel and modulation conditions.
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Selvarasa, G. (Gowshigan). "Map-based channel model parameterization and comparison of three different deterministic channel modelling methods." Master's thesis, University of Oulu, 2019. http://jultika.oulu.fi/Record/nbnfioulu-201907162704.
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Abstract. The interest in studying the channel characteristics is exponentially increasing with the growth of the communication systems. Various channel modelling approaches have been discussed in the past decades. The ray-tracing based channel models are distinguished from the other channel models as they consider the environmental information and thus are expected to reflect the real propagation phenomena that exist in that specific environment. The goal of this thesis is to study the propagation channel characteristics of the three different channel models. The two deterministic channel models are the simplified map-based ray tracing channel model implemented in the METIS project and the full ray tracing-based channel model implemented by the Beijing Jiaotong University. The third channel model is the hybrid model based on METIS map-based channel. It uses the deterministic part of the METIS map-based channel model.
Full ray-tracing based models require detailed description of the propagation environment or map and they target on site-specific channel modelling. Such site-specific models are not typically required in performance testing of devices, where the target is to ensure device performance in a typical propagation environment and possibly to cover some extreme cases. The simplifying map-based approach contradicts with the full ray tracing method in the way that the information of the map is reduced by approximating the building shapes and introducing artificial tiles to make scattering in the walls and ground reflections. Map-based channel modelling provides additional realism in channel models compared to traditional stochastic models applied in performance testing.
The urban street canyon scenario was chosen to be modelled. The comparison was carried out at 3.5 GHz by means of performance metrics such as total path loss, LOS and NLOS propagation conditions at UE positions, K-factor, RMS delay spread, statistics of angles, angle spreads, and cross polarization ratios.
The results have showed similarities in the LOS UE positions and dissimilarities in the NLOS UE positions. The reasons are identified and explained in the discussion section. It is decided to investigate the radio channel characteristics of the METIS map-based channel model and hybrid channel model for the future study purpose.
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Sasiakos, Christos. "A 3D spatial channel model for cellular radio." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2000. http://handle.dtic.mil/100.2/ADA384906.
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Arvidsson, Pontus. "Channel Estimation Error Model for SRS in LTE." Thesis, KTH, Signalbehandling, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-53769.
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In 3GPP long term evolution (LTE), sounding is used to gain a wideband estimate of the uplink channel. This channel estimate may then be used for several radio resource management related applications such as frequency selective scheduling and beam forming. Code division multiplexing (CDM) enables several users to broadcast sounding reference signals (SRS) simultaneously on the same time and frequency resource. As the multiplexed users may interfere with one another there is a trade-off between having users broadcast SRS as often as possible to get a frequent channel estimate and getting higher quality estimates with a lower periodicity. To assess this trade-off one must have a good understanding of what causes the errors in the channel estimate so that the sounding resource may be used as efficiently as possible. This thesis proposes a method to model the channel estimation error with sounding for use in a system simulator environment. The method consists of estimating a standard deviation with a per-resource-block resolution of the channel estimates as a function of received signal powers of interfering users as well as the target user and background noise. This estimated estimation error may then, in the system simulator, be applied to a known ideal channel estimate as noise. The main limiting source of error is shown to beinterference, both from sounding users in the same cell and in others as well as some effects of limited frequency resolution. Simulation results indicate that a cleverly designed sounding resource handler is needed to fully utilize the possible gains of sounding.
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Nangunoori, Chetan Kumar, and Bhaskar Ravichandra Kumar Kumar. "Parametric Ram Air Channel Model for Flow Optimization." Thesis, Linköpings universitet, Fluida och mekatroniska system, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-80069.
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Ram air channel or NACA channel is used to direct the ambient air for various purposes in an aircraft, such as pressurizing the cabin or as a coolant to heat exchangers and even more other applications like a cooling of the coolant. It is designed; such that it supplies the required amount of ambient air for various operations as mentioned, even aero-dynamical features should be taken into consideration while designing. In past, the developed prototypes are to be designed first and then experimented to optimize the design which gives accurate predictions and makes easy to understand the phenomenon occurring. These methods can lead to lot of waste in resources and time, in order to avoid these, some new mathematical methods have been implemented before finalizing the prototype which might save resources, time and minimize the possibility of having wrong outcomes. Some additional steps are included during calculation stage prior to the prototype stage; they are the computer aided simulations. These simulations can be as accurate as real time simulations and can bring closer to accuracy rate which is a needed prior to prototype stage. The aim is to design a tool chain for a Ram air channel which in turn is used to optimize the flow, then supplied to heat exchangers for cooling the hot refrigerant from the avionics systems. The requirements of the heat exchanger are decided on the applications it is used and the range of temperature to be cooled. In this study work, firstly estimate the size of the heat exchanger for the required performance, followed by the geometry of Ram air channel designing in CAD application so that it maintains the required amount of mass flow rate for the performance of heat exchanger. Finally these both components are implemented in simulation loop to iterate the designs of NACA channel in order to get the final model to optimize the flow for a heat exchanger.
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Kim, Jae Gak. "A kinetic model for the HCN2 ion channel." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44696.
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The focus of my investigation is the hyperpolarization-activated cyclic nucleotide-gated cation (HCN) channel, also known as the pacemaker channel. There are four mammalian isoforms (HCN1-HCN4) that share about 60% sequence identity with each other, all activated by hyperpolarization of the membrane potential and permeable to both potassium and sodium. The major differences among four isomers are their responses to binding of cyclic adenosine monophosphate (cAMP), the rate of channel opening and closing, and their dependence on voltage. Recent studies have suggested that the opening and closing of HCN channels involve a step that is voltage independent, which depends upon a region that resides within the S4 and S6 transmembrane region. My study is based upon recent data from the Accili lab in which substitution of a phenylalanine (F) residue near the inner activation gate of the HCN2 channel to alanine (A) dramatically and preferentially slows down channel closing and decreases the dependence of closing on voltage. A 6-state, but not a 4-state, cyclic allosteric model incorporating voltage-dependent transitions moving the channels between resting and active states and voltage-independent transitions between closed and open states was able to describe the complex opening and closing of both the wild type and F/A mutant channels in response to changes in voltage. These models also predicted a significant opening probability between the open and closed states when the channel resides in the resting state.
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Chong, Chia-Chin. "Dynamic directional channel model for indoor wireless communications." Thesis, University of Edinburgh, 2003. http://hdl.handle.net/1842/13378.
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The frequency-domain space alternating generalised expectation-maximisation (FD-SAGE) algorithm is proposed and used in conjunction with the serial interference cancellation (SIC) technique for joint detection and estimation of multipath channel parameters. The SIC technique demonstrates more stable performance than the parallel interference cancellation (PIC) technique used in the time-domain SAGE algorithm especially in a multipath rich environment. The performance of the FD-SAGE algorithm is demonstrated by using real indoor channel measurement data and its functionality is verified through comparison with unitary estimation of signal parameter via rotational invariance technique (ESPRIT) algorithm. The first channel model is derived from data collected during a static measurement campaign. This model incorporates both the clustering of MPCs and the correlation between the spatial and temporal domains. The clustering effect relies on two classes of parameters (intercluster and intracluster parameters) and two classes of power density spectra (PDS) (intercluster and intracluster PDS) which characterise the cluster and MPC, respectively. All parameters are described by empirical probability density (pdfs) derived from the measured data and the correlation properties are incorporated in two joint pdfs for cluster and MPC positions. Data analysis shows that the intercluster and intracluster PDS exhibit exponential and Laplacian functions in the delay and angular domains, respectively. The second channel model is derived based on data collected during a dynamic measurement campaign. This model incorporates both the spatial-temporal properties as well as the dynamic evolution of paths due to motion of the MT. An M-step, 4-state Markov channel model (MCM) is proposed in order to account for the correlation between the number of births and deaths and multiple births and deaths that can occur at any time instant. The power and spatio-temporal variation of paths within their lifespan are modelled by a low-pass-filter and a Gaussian distributed spatio-temporal vector, respectively. Due to the distinction in the birth-death statistics and the spatio-temporal dispersion and correlation properties for line-of-sight (LOS) and non-LOS (NLOS) scenarios, the model can be generalised, and parameterised by two sets of Markov parameters for these two scenarios.
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Zhang, Tao. "Complex Sound Discrimination and A Correlated Channel Model /." The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487929230741499.
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Schena, Michael L. "An Electromagnetic Coupling Model for Side-Channel Analysis." DigitalCommons@USU, 2016. https://digitalcommons.usu.edu/etd/5224.
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This thesis presents an EM coupling model used to enhance power, side-channel measurements used in CPA. The Kalman filter is used to combine measurements of magnetic flux density with voltage or current traditionally used to measure power consumption. The DES encryption algorithm is used to evaluate CPA using EM coupled power measurements compared to traditional power measurements.
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Rice, Michael, and Qiang Lei. "SHF MULTIPATH CHANNEL MODELING RESULTS." International Foundation for Telemetering, 2005. http://hdl.handle.net/10150/604799.
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ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, NevadaThis paper presents the results of land-based SHF channel modeling experiments. Channel modeling data were collected at Edwards AFB, California at S-Band, X-Band and Ku-band. Frequency domain analysis techniques were used to evaluate candidate channel models. A graphical user interface (GUI) was developed to search for the optimum channel parameters. The model parameters corresponding to different frequencies were compared for multipath events captured at approximately the same locations. A general trend was observed where the magnitude of the first multipath reflection decreased as frequency increased and the delay remained relatively unchanged.
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Rainbird, Peter Charles Bruce. "Depth averaged numerical modelling in channel bends." Thesis, University of East Anglia, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317973.
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Binza, Lungile. "Factors influencing the decision to transition from Multi-Channel to Omni-Channel – A Banking Perspective." Master's thesis, Faculty of Commerce, 2021. http://hdl.handle.net/11427/32603.
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Banking through insufficiently coordinated and non-integrated channels (Multi-Channel) is slowly being discarded. With Omni-Channel banking, where channels are integrated and data and information are shared across cross channels, customers are in control of the channels they wish to use. Factors influencing the organisational decision to transition from Multi-Channel to Omni-Channel hasn't been fully explored. Is this decision responding to internal factors like efficiency improvements, or is it driven by external factors like customer demands, trying to enhance customer experience, gaining competitive advantage over the competitors, expanding the business by introducing new business models, or trying to gain access to smart technologies for financial benefit? This dissertation presents research findings into the investigation of factors that influence the organisational decision to transition from Multi-Channel to Omni-Channel banking. A positivist case study with inductive reasoning was adopted. Qualitative data was collected from a single organisation through interviews together with observations of the strategy documents between January 2019 and April 2019. An initial conceptual model was derived from the literature review to guide data collection, after which thematic analysis was used to analyse the data and develop an emergent theory. The key findings from the research study are that a customer centric approach informs the decision to transition. The customer is at the centre of the omni-channel strategy: that is through an enhanced customer experience or timeously responding to customer demands. Other factors are either enabling this strategy, like technological innovations, and efficiency improvements or are the outcome of the strategy like customer satisfaction, revenue or cost optimisation, and competitive advantage. The key implications are that organisations must pay more attention to the customer journey and ensure that they advance in the Customer Experience Capability Maturity Model. Most successful business transitions to the Omni-Channel strategy require a transformation in organizational culture, operations and processes, and the underlying technologies.
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Papazoglou, Panayotis M. "Simulation model architectures for channel allocation in cellular networks." Thesis, University of Portsmouth, 2010. https://researchportal.port.ac.uk/portal/en/theses/simulation-model-architectures-for-channel-allocation-in-cellular-networks(dcd7af72-afe2-4971-b0c6-155e5fdb0d84).html.
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Channel allocation is a fundamental issue in cellular networks because it determines how the available bandwidth will be managed. The limited channel availability and the increasing demands for advanced services. such as real time video, gave to channel allocation strategies a special role; hence, cellular network adaption to current traffic conditions is the most challenging issue. In the literature, a great number of channel allocation strategies have been proposed for supporting voice services as well as multimedia services. This study shows that the performance of the existing approaches regarding the channel allocation for voice and multimedia services can be significantly improved by proposing new criteria for channel allocation and by introducing new modelling methodologies especially for large scale environments. Additionally, an ant colony optimization algorithm for channel allocation in large scale environments is introduced for the first time in literature. Simulation solutions, on the other hand, offer the opportunity to develop and evaluate channel allocation schemes, network structures etc, towards a desired cellular network. A main goal of a simulation model is the reflection of the network event activities based on the channel allocation strategies. In this study, the cellular network is modelled using a novel methodology based on multi-agent technology. This methodology constitutes a new simulation approach and a new network behaviour concept regarding channel allocation. Moreover, a novel event scheduling mechanism is proposed for improved channel allocation and for reflecting the cellular network behaviour. In the literature, an event scheduler focused on channel allocation and multi-agent based modelling for network services do not exist. Finally, a new simulation system where the multi-agent technology and the event scheduling mechanism for channel allocation are integrated is analysed and proposed. The results clearly show that the proposed channel allocation strategies produce improved performance in large scale cellular networks regarding the voice and multimedia services. The results also show that the performance of the cellular network is significantly improved when the new modelling methodology based on multi-agent technology is applied in combination with the proposed event scheduling mechanism focused on channel allocation.
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Belcher, Brian James. "VORTEX MODEL OF OPEN CHANNEL FLOWS WITH GRAVEL BEDS." UKnowledge, 2009. http://uknowledge.uky.edu/gradschool_diss/702.
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Turbulent structures are known to be important physical processes in gravel-bed rivers. A number of limitations exist that prohibit the advancement and prediction of turbulence structures for optimization of civil infrastructure, biological habitats and sediment transport in gravel-bed rivers. This includes measurement limitations that prohibit characterization of size and strength of turbulent structures in the riverine environment for different case studies as well as traditional numerical modeling limitations that prohibit modeling and prediction of turbulent structure for heterogeneous beds under high Reynolds number flows using the Navier-Stokes equations. While these limitations exist, researchers have developed various theories for the structure of turbulence in boundary layer flows including large eddies in gravel-bed rivers. While these theories have varied in details and applicable conditions, a common hypothesis has been a structural organization in the fluid which links eddies formed at the wall to coherent turbulent structures such as large eddies which may be observed vertically across the entire flow depth in an open channel. Recently physics has also seen the advancement of topological fluid mechanical ideas concerned with the study of vortex structures, braids, links and knots in velocity vector fields. In the present study the structural organization hypothesis is investigated with topological fluid mechanics and experimental results which are used to derive a vortex model for gravel-bed flows. Velocity field measurements in gravel-bed flow conditions in the laboratory were used to characterize temporal and spatial structures which may be attributed to vortex motions and reconnection phenomena. Turbulent velocity time series data were measured with ADV and decomposed using statistical decompositions to measure turbulent length scales. PIV was used to measure spatial velocity vector fields which were decomposed with filtering techniques for flow visualization. Under the specific conditions of a turbulent burst the fluid domain is organized as a braided flow of vortices connected by prime knot patterns of thin-cored flux tubes embedded on an abstract vortex surface itself having topology of a Klein bottle. This model explains observed streamline patterns in the vicinity of a strong turbulent burst in a gravel-bed river as a coherent structure in the turbulent velocity field.
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Schneckenburger, Nicolas [Verfasser]. "A Wide-Band Air-Ground Channel Model / Nicolas Schneckenburger." München : Verlag Dr. Hut, 2018. http://d-nb.info/1155058712/34.
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Darby, Stephen E. "A physically-based numerical model of river channel widening." Thesis, University of Nottingham, 1994. http://eprints.nottingham.ac.uk/13497/.
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The application of many existing numerical models of river channel morphology is limited by their inability to account for bank erosion and changing channel width through time. In this research, a physically-based numerical model which simulates the evolution of channel morphology, including channel width, through time has been developed and tested. Predictions of channel evolution are obtained by solving deterministically the governing equations of flow resistance, flow, sediment transport, bank stability and conservation of sediment mass. The model is applicable to relatively straight, sand-bed streams with cohesive bank materials. In the channel evolution model, a method is used to solve the shallow water flow equations, and to account for lateral shear stresses which significantly influence the flow in the near bank zone. The predicted distribution of flow is then used to predict the sediment transport over the full width of straight river channels. Deformation of the bed is calculated from solution of the sediment continuity equation. Predictions obtained in the near bank zone allow the variation in bank geometry to be simulated through time. Since bank stability is determined by the constraints of the geometry of the bank and the geotechnical properties of the bank material, channel widening can, therefore, be simulated by combining a suitable bank stability algorithm with flow and sediment transport algorithms. In combining bank stability algorithms with flow and sediment transport algorithms, there are two paramount considerations. First, the longitudinal extent of mass failures within modelled reaches must be accounted for. Second, it is necessary to maintain the continuity of both the bed and the bank material mixture in the time steps following mass failure, when the bed material consists of mixtures of bed and bank materials with widely varying physical properties. In this model, a probabilistic approach to prediction of factor of safety is used to estimate the fraction of the banks in the modelled reaches that fail in any time step. Mixed layer theory is then used to model the transport of the resulting bed and bank material mixture away from the near bank zone. Comparisons of model predictions with observations of channel geometry over a 24 year period indicate that the new model is capable of simulating temporal trends of channel morphology with a high degree of accuracy. The model has been used successfully to replicate the form of empirically-derived hydraulic geometry equations, indicating that the model is also able to predict stable channel geometries accurately. The numerical model has also been used to investigate the influence of varying the independent variables and boundary conditions on channel adjustment dynamics.
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Willgoose, Garry Raymond. "A physically based channel network and catchment evolution model." Thesis, Massachusetts Institute of Technology, 1989. http://hdl.handle.net/1721.1/14316.
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Welborn, Matthew L. "Co-channel interference rejection using a model-based demodulator." Thesis, This resource online, 1995. http://scholar.lib.vt.edu/theses/available/etd-01312009-063544/.
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Nelson, N. Thomas. "Probability of Bit Error on a Standard IRIG Telemetry Channel Using the Aeronautical Fading Channel Model." International Foundation for Telemetering, 1994. http://hdl.handle.net/10150/611662.
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International Telemetering Conference Proceedings / October 17-20, 1994 / Town & Country Hotel and Conference Center, San Diego, CaliforniaThis paper analyzes the probability of bit error for PCM-FM over a standard IRIG channel subject to multipath interference modeled by the aeronautical fading channel. The aeronautical channel model assumes a mobile transmitter and a stationary receiver and specifies the correlation of the fading component. This model describes fading which is typical of that encountered at military test ranges. An expression for the bit error rate on the fading channel with a delay line demodulator is derived and compared with the error rate for the Gaussian channel. The increase in bit error rate over that of the Gaussian channel is determined along with the power penalty caused by the fading. In addition, the effects of several channel parameters on the probability of bit error are determined.
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Sakarai, Deesha S. "Wireless Channel Characterization for Large Indoor Environments at 5 GHz." Ohio University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1338494030.
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Mesini, Leonardo. "3GPP 5G Channel and Traffic Model for Industrial IoT Applications." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
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Nowadays the concepts of ”smart factory” and ”Industry 4.0” are very important because they represent the last industrial revolution, which promises to have a huge impact on human lives and on the production cycles of every industry. The main driver of this revolution is the 5G technology which is able to provide higher performance by means of ultra low latency, very high multi-Gbps peak data rate and massive connectivity.
In light of these considerations, it is vital that appropriate channel models and traffic models for the industrial environment are elaborated. Indeed, the industrial environment is characterised by particular features which are not present in other scenarios, even in the indoor scenario that can seem the most similar.
This thesis focuses on the latest channel model proposed by 3GPP and on the traffic model suggested by 5G-ACIA through a white paper. In order to deploy a flexible industrial environment where all machineries are interconnected, can communicate with each other and can be controlled remotely, it is fundamental to understand how the channel model can be defined and how the traffic generated can be characterised.
The main features of the 3GPP channel model are pointed out, by focusing in particular on the industrial scenario, and the peculiar parameters of the traffic model are highlighted. After that, the two models are applied to the BI-REX pilot line, which represents a peculiar example of new production line where the traditional technologies are integrated with new ones in order to obtain a fully interconnected industrial environment.
The thesis aims at showing how to set the most important parameters of the two models and the most common use cases in an industrial traffic model. It represents a starting point for new works that want to implement these models.
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Nevinskiy, D. V., V. A. Pavlysh, L. I. Zakalyk, and Y. S. Lebid. "Four Channel Splitter on Surface Plasmons-Polaritons." Thesis, Sumy State University, 2015. http://essuir.sumdu.edu.ua/handle/123456789/42551.
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Modeling process of surface plasmon polaritons-(SPP) distribution in the 10 mm long four channelsplitter is discussed in current paper. 20 mm long two channel splitter was formed by the projection optical lithography in order to test the model relevancy. Studies have shown that excited SPP propagates along both channels in a dual channel splitter.
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Lowe, Sidney. "Channel strategy for export distribution: towards a channel strategy model for non-multinational manufacturingfirms in Hong Kong." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1988. http://hub.hku.hk/bib/B31949319.
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Wang, Yao Electrical Engineering & Telecommunications Faculty of Engineering UNSW. "Single channel speech enhancement based on perceptual temporal masking model." Awarded by:University of New South Wales. Electrical Engineering & Telecommunications, 2007. http://handle.unsw.edu.au/1959.4/40454.
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In most speech communication systems, the presence of background noise causes the quality and intelligibility of speech to degrade, especially when the Signal-to-Noise Ratio (SNR) is low. Numerous speech enhancement techniques have been employed successfully in many applications. However, at low signal-to-noise ratios most of these speech enhancement techniques tend to introduce a perceptually annoying residual noise known as "musical noise". The research presented in this thesis aims to minimize this musical noise and maximize the noise reduction ability of speech enhancement algorithms to improve speech quality in low SNR environments. This thesis proposes two novel speech enhancement algorithms based on Weiner and Kalman filters, and exploit the masking properties of the human auditory system to reduce background noise. The perceptual Wiener filter method uses either temporal or simultaneous masking to adjust the Wiener gain in order to suppress noise below the masking thresholds. The second algorithm involves reshaping the corrupted signal according to the masking threshold in each critical band, followed by Kalman filtering. A comparison of the results from these proposed techniques with those obtained from traditional methods suggests that the proposed algorithms address the problem of noise reduction effectively while decreasing the level of the musical noise. In this thesis, many other existing competitive noise suppression methods have also been discussed and their performance evaluated under different types of noise environments. The performances were evaluated and compared to each other using both objective PESQ measures (ITU-T P.862) and subjective listening tests (ITU-T P.835). The proposed speech enhancement schemes based on the auditory masking model outperformed the other methods that were tested.
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O'Shaughnessy, Richard Denis. "A discrete multi-channel model of a diesel particulate filter." Thesis, Queen's University Belfast, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.479402.
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Rice, Michael, and Qiang Lei. "A WIDEBAND CHANNEL MODEL FOR SHF-BAND TELEMETRY OVER WATER." International Foundation for Telemetering, 2007. http://hdl.handle.net/10150/604576.
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ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, NevadaData recorded during multipath channel sounding experiments, conducted off the coast of Pt. Mugu Naval Air Station at 8.0 GHz was used to model the multipath interference at SHF band over water. The modeling results show that a three ray model consisting of line-of-sight propagation and two reflected propagation paths is a good fit for the measured channel frequency responses. The properties of the multipath reflections are determined by geometry and sea state. For calm seas, the first reflection is a large amplitude short-delay reflection whereas for rough seas, the first reflection has a smaller amplitude and longer delay. The second reflection has a smaller amplitude and larger delay when the sea is calm.
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Sangameswaran, Sivaramakrishnan. "Water quality modeling of a storm water channel." ScholarWorks@UNO, 2003. http://louisdl.louislibraries.org/u?/NOD,52.
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Thesis (M.S.)--University of New Orleans, 2003.Title from electronic submission form. "A thesis ... in partial fulfillment of the requirements for the degree of Master of Science in Environmental Engineering"--Thesis t.p. Vita. Includes bibliographical references.
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Chi-Yuan, Chen, and 陳啟元. "Physical Channel and Virtual Channel Power Model Comparison." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/68996101214061792467.
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碩士亞洲大學
經營管理學系碩士班
97
In today's society, often have the channel predominant the marketing. Application of science and technology network in the commercial prosperity of increasing competition in the business has changed the structure of the end of the 20th century, from which the electronic commerce (E-commerce) is produced, providing an alternative channel model for selling products. With the development of the E-commerce, enterprises have to face a new business model, and supply chain management (SCM) is the optimal solution to implement and integrate E-commerce and competitive advantage of outsourcing. However, in retailer channel industry, among the upstream and downstream there generally exists unequal channel power, there is no confidence and power imbalances, and the conflicts among channel members impact on the cooperation and growth between both the manufacturers and channel retailers, which also trouble all practitioners in channel industry. This study aimed at the channel power source and the channel power itself in the channel power of Taiwan’s physical channel and virtual channel clothing industry to explore the causal relationship of the degree of satisfaction of the channel members. This study discovered that both the channel power sources and the channel power have positive direct impact on the degree of satisfaction, because the competition is fierce in the channel retailer market of Taiwan’s clothing industry. Therefore the channel distributors and the channel retailers can take and maintain mutually beneficial cooperative model, hoping by such a power model so that the both sides are able to reap greater benefits.
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Pen-Ting, Sun, and 孫本庭. "Similarity of Discrete Gilbert-Elliot and Polya Channel Models to Continuous Rayleigh Fading Channel Model." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/70685636259962256778.
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碩士國立交通大學
電信工程系
90
In this thesis, the concept of channel similarity is explored by two different methodologies---an analytical methodology based on divergence, and an empirical methodology based on error free run matching. In the analytical methodology, we showed that divergences can serve as an index to channel similarity. We then proceeded to compare the resemblance between the Gilbert-Elliott and Polya channels, and obtained that for some very specific case, the two channels are not similar to each other. In the empirical methodology, we examined which of the two channel models, Gilbert-Elliott and Polya, is more suitable to approximate the binary-quantized simplification of a continuous multipath Rayleigh fading channel. In terms of the EFR quantitative index, we showed that the Gilbert-Elliott channel is a better approximation to the binary-quantized multipath Rayleigh fading channel than the Polya model. A side result is that among all Rayleigh fading channels examined, the Gilbert-Elliott channel is particularly suitable to represent a two-path Rayleigh fading channel.
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Chih-Yu, Lai, and 賴致宇. "A Study of 3D Channel Model." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/22462959043259388723.
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碩士國立臺北大學
通訊工程研究所
103
In this paper, we study the WINNER II channel model, which is used by the 3GPP standard society. Due to its accuracy, this channel model facilities the study of the most cutting-edge wireless communications techniques. Currently, the channel model has evolved from 2-Dimension to 3-Dimension channel modeling. By including the extra dimension, i.e. the axis of the elevation, the base station may increase the resolution of the mobile users. That is, it eliminates the near-far issue caused by mobile users located in close proximity. In other words, the capacity of the mobile users served by the base station may be increased due to techniques designed based on 3D channel modeling, comparing to the ones designed based on 2D channel modeling. Hence, in this paper, we investigate and realize the 3D channel model based on the WINNER II channel model.
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Noble, Stephanie M. "Consumers' channel preferences: An integrated model." 2001. https://scholarworks.umass.edu/dissertations/AAI3012172.
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With the growing popularity of the internet as a channel of distribution many researchers are trying to determine factors that influence and hinder consumers' acceptance of this channel. Unfortunately, the explosion of articles studying internet patronage involve the same limitation as previous shopping motivation research. Namely, the internet is just one of many channels from which consumers' can choose to purchase products. Current articles on internet patronage, as well as the previous work on other channels, have failed to account for this fact. These studies examine patronage motives one channel at a time, while neglecting to account for how consumers choose between channels. As such, the main goal of this study was to develop an integrative consumer channel preference model which would allow for a comparison across channels to determine which factors are the most influential for each channel. Participants for this study consisted of individuals 16 and older who had access to the internet. This sample was chosen to ensure that consumers have some type of access to the internet, which is essential for any on-line purchases. Two-thousand consumers were mailed a 6-page survey asking for their participation. Eight-hundred and one consumers returned the completed questionnaire (40% response rate), with 754 included in subsequent analyses due to a pre-qualification question. The results showed that product class knowledge, familiarity/prior use with a purchasing channel, and immediate possession motives were the only predictors that influenced consumers' preferences for all three channels included in this study (i.e., bricks-and-mortar, catalogs, and internet). Other factors influencing channel preferences included risk aversion, merchandise uniqueness motives, loyalty to local merchants, catalog recreation motives, and the respondent's age. Despite the large number of constructs investigated in the current study only seven were consistently significant predictors of consumers' bricks-and-mortar preferences. Six consistently predicted catalog preferences, and only three predicted internet preferences. Additionally, these variables accounted for a small portion of the variance explained in consumers' channel preferences (ranging from 11% to 39%), with catalog models explaining the least variance. These results suggest that there are many other factors and motives that influence consumers' channel preferences than were captured in the current study.
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LIN, ZAN-XI, and 林讚西. "A unified I-V model for short channel MOSFETs with implanted channel." Thesis, 1988. http://ndltd.ncl.edu.tw/handle/85058718927802808353.
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Wang, Tzu-Lin, and 王姿琳. "Multi-channel MAC Protocols by Applying Staggered Channel Model for Wireless Networks." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/vbh8jp.
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博士淡江大學
資訊工程學系博士班
102
Developing the multichannel Media Access Control (MAC) protocol is the key technique for improving the utilization of wireless spectrum. One of the major challenges to develop the multichannel MAC protocol is the well-known “Rendezvous Problem”. The rendezvous problem occurs since the sender cannot be aware of the channel where the receiver stayed. Therefore, the sender is unable to exchange control packets with its receiver. To overcome rendezvous problem, existing multichannel MAC protocols can be classified into three types, including Control-Control Based (CCB), Hopping Based (HB), and Control-Period Based (CPB) channel models. Although above-mentioned three channel models can resolve rendezvous problem, they still have some disadvantages. In CCB channel model, each node cannot maintain the complete channel usage information since it did not stay at the control channel. That is, when a pair of sender and receiver exchanges data on a data channel, they cannot overhear the control packets exchanged on the common control channel. The pair of sender and receiver may attempt to reserve a data channel where other pair occupied, and hence the Multichannel Hidden Terminal Problem (MHT-Problem) occurs. On the other hand, in HB channel model, each node follows a predefined hopping sequence, hoping to different channels at each time slot. Nevertheless, all nodes switching to a channel at the same time slot lead to the contention and collision phenomena. In CPB channel model, each node should switch to the negotiation window of a predefined channel in every beacon interval, aiming to rendezvous with its receiver and then exchange control packets. However, the low channel utilization problem will be arisen. This occurs because the negotiation windows of all channels other than the default channel will not be used. This thesis firstly proposes a novel multichannel model, called Staggered Channel Model. In the proposed staggered channel model, the negotiation windows of all channels are arranged to be staggered. Moreover, by applying the proposed staggered channel model and basic transmission rules, each node overcomes rendezvous, MHT, and low channel utilization problems, improving the network capacity. In addition, this thesis proposes two multichannel MAC protocols based on the staggered channel model for cooperative networks and cognitive radio networks. In the signal-fading and interference-rich network environment, high probability of failure transmission results in low network performance. To improve communication reliability, the proposed CM-MAC protocol allows that each sender selects enough number of cooperative nodes as soon as possible when transmission fails. Then, the sender simultaneously transmit data with the selected cooperative node to the receiver. Simulation results show that the proposed CM-MAC protocol not only scientifically improves the packet delivery ratio and network throughput but also decreases the control overhead. For cognitive radio networks, this thesis proposes the SMC-CR-MAC protocol to continue the transmission of secondary users (SUs) without interfering with the data exchange of primary users (PUs). Since the PU may appear at any time and location, the proposed SMC-CR-MAC protocol takes the timing and location of PU appearance into account and develops different policies to continue the unfinished data exchange of SU pairs. Performance evaluation shows that the proposed SMC-CR-MAC protocol can improve the successful rendezvous probability between SU sender and receiver, enhance network throughput, and reduce the transmission delay of SU pair when PU is detected.
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Lee, Tai-Ling, and 李岱玲. "Study on Channel Migration in Meandering Compound Channel Flow Using CCHE2D Model." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/76511659380876910381.
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碩士國立交通大學
土木工程學系
101
Most of the main channels of alluvial rivers are meanders. The main channel becomes the compound channel confined by the embankments during rise of flood. Assessment of channel migration and bed erosion in meandering compound channel is necessary. The aim of this research is to investigate channel migration in meandering compound channel with inbank and overbank flows using CCHE2D model. Numerical simulations of two experimental bends show the characteristics of the secondary flow. Validations of the model, using sine-generated experimental data with bank erosion, have been performed. The model was also applied to study the morphological changes of experimental meandering compound channels and field case in Tseng-Wen Creek under changing conditions of flow and sediment. Good agreements between the simulated and available laboratory measurements were obtained. According to simulation results, the discharge in the main channel affects the stability of the main channel. The discharge in the floodplain of compound channel increases as the water depth increases, and the effect of the centrifugal force decreases. The results also point out the importance of the flow interaction between main channel and floodplain under overbank flow condition.
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Gu, Zhenguo. "Polytype analysis of FIR channel model theory and applications to channel equalization /." 1993. http://catalog.hathitrust.org/api/volumes/oclc/30116894.html.
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Thesis (Ph. D.)--University of Wisconsin--Madison, 1993.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 112-117).
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Wu, Ming-Yang, and 吳明洋. "3GPP TR 36.873 3D Channel Model for LTE Theory and Implementation : UE Attachment, Antenna Model and Channel Coefficients." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/xyj78u.
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碩士國立中正大學
通訊工程研究所
104
The formulation of the standards of 3GPP long term evolution-advanced (LTE-A) 4G systems is almost complete, with Release 12 being completed in the second quarter of 2014. Moreover, 3GPP LTE/LTE-A networks are being continually developed worldwide. Concurrently, 5G mobile communication systems have attracted considerable research attention among major communication companies worldwide. To ensure practical applicability, simulators must be developed for evaluating the design performance of such systems. Therefore, the objective of this study was to create a spatial channel model that conforms to international standards. To achieve this objective, this study applied the wrap-around method and subjected parameters to large-scale correlation analyses on the basis of 3GPP TR36.873 documentation (“Study on 3D channel model for LTE”) to generate a channel response with spatial properties. This model was integrated with an antenna on a 2D plane to ensure an accurate system performance evaluation. This paper describes the details about the antenna model implementation, channel coefficient generation, and user equipment attachment.
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McGlynn, D'Arcy. "MODEL DEVELOPMENT FOR MICRO–CHANNEL COOLING TECHNOLOGY." Thesis, 2013. http://hdl.handle.net/10012/7521.
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The micro–channel research literature presents a clear need to provide accurate models that can predict pressure drop and heat transfer coefficients for a greater number of experimental data sets while capturing the physical phenomena of various flow patterns associated with the onset of nucleate boiling in the two–phase region. The model approach developed have been evaluated for the purpose of facilitating an efficient design instrument for micro–channels to predict the pressure drop related to heat input for the single phase through to the boiling [two–phase] region as well as heat transfer coefficient calculations for a single micro–channel. The simplified homogeneous model provides a lower bound for pressure drop estimates and the weighted annular–homogeneous model produces an upper bound value. Input parameters include the micro–channel dimensions, fluid flow rate, inlet temperature, thermo–physical properties of the respected fluid, and outlet pressure. Polynomial correlations for water are obtained from curve–fitting data available from the 1997 Ashrae Handbook over the temperature range of 0.01 to 200 ºC for the thermodynamic properties that include liquid density, viscosity, thermal conductivity, specific heat capacity and change of enthalpy [latent heat of vapourization].
The model results are evaluated over four independent experimental data sets that are available in the literature to demonstrate the sufficient accuracy for channel dimensions ranging from 50 µm to 713 µm. The independent data sets were numerically reproduced from figures presented in the research literature. The boiling front, pressure drop, heat transfer coefficient, wall temperature profile and vapour quality characteristics are evaluated. Heat transfer coefficient calculations were made via the Kandlikar correlation and the Kandlikar enhancement factor method that is corrected for vapour quality. The model produced pressure drop results that were within about a 30% error to the experimental data sets evaluated for heat fluxes in the range of 50 W/cm² to values exceeding 150 W/cm². Heat transfer coefficient values calculated between the two correlations of Kandlikar were within an estimated error of 30% to experimental measurements and demonstrated results in the two–phase region that exceeded 110 000 W/cm² K.
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Chang, Wei-Che, and 張維哲. "Study of CD-R Write Channel Model." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/40904276817236842581.
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碩士國立成功大學
電機工程學系
88
CD-R discs have become an important medium in mass data storage. The high capacity discs are capable of storing data temperately or permantly. However, in order to control the laser to the correct position and power, many control-related issues need to be addressed. This thesis investigates the write channel characteristic of a typical CD-R. Through analytical and experimental work, a simple write channel model is established and verified. The write channel model is then used in the write power control. It is shown that running optimal power control can be conducted more effectively with the write channel model at hands.
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Lee, Hua-Lung, and 李華龍. "DiscussInnovative Business Model of Food Marketing Channel." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/3649f5.
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碩士輔仁大學
企業管理學系管理學碩士在職專班
105
Abstract: Theearly-stage of market access to foodstuff were started from manufacturers and importers of origin to the traditional market, wholesalers then sold to local, retailers and finally sold to the restaurant and household buyers. The fresh supermarket appeared which gives another new chooses to the buyer to approach food with more flexible and more efficient way. Recently, due to the vigorous development of e-commerce and advanced of portable software, the fresh food becomes a new product to the e-commerce or what we called “E-food”. E-food is not only very convenient to the families, but also to the restaurant and night market. The ever-changing era, people is no longer attract to the fresh food or e-food. The food revolution is beginning. Nowadays, there is new way to approach food with fresh, cheap, rapid is developed and we called it called “group buy”. This new sale style creates an innovation and opportunity the food legend. Therefore, the research papers hope that through the current several more successful and efficient access providers from the market via interview process to understand their successful mode of operation, and summed up a set of the new retail access which can be applied to all the local consumers in Taiwan, including the restaurants and family buyers can benefit from the new retail access. This research is analyzed the successful strategies and most effective ways from the four different types of retail accesses and integrated with the business model canvas to find out all the strengths and weakness from those four retails access and establishing an innovative business model. finally summed up a set of four advantages, the combination of innovative business model as the path of this business model can be improved, and to enable it to expand business scale and increase profitability.
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wu, feng-nan, and 吳鋒南. "Hidden Markov Model Applied in Wideband Channel." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/97505047813141506350.
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碩士國立臺北科技大學
電腦通訊與控制研究所
92
In this paper, we proposed a new wideband channel simulator based on the measurement data. The variation of the power of first arrival and rms delay spread was extracted from measurement data and inputted to hidden Markov Model as the training sequence. We found the relationship between the variant of observation sequences and hidden states sequence with Viterbi Algorithm. A joint steady-state was built according to the two state sequences. The two parameters were reproduced by hidden Markov model with the joint steady-state. The wideband channel constructed completely with the two parameters and near-far echo model. The statistic between the two parameters from measurement data and reproduced data from hidden Markov model were almost the same.
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Cheng, Ting-Hsu, and 鄭亭煦. "Research and Analysis of Spatial Channel Model." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/8ae5s5.
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碩士國立臺灣科技大學
電子工程系
107
This thesis is aimed at the simulation of Spatial Channel Model published by IMT 2020 and TR 38.901. Set Urban Macro with URLLC (Ultra Reliable and Low Latency Communications) as the simulation environment. The content is based on the progress of building the simulation system, and detail the test environment, operation mode and related parameters. The simulation program gradually set up the long term parameters and short term parameters which related to t he Spatial Channel Model in C++.
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Lai, Ching-Ying, and 賴靜瑩. "The Choice Model of Travel Products-Comparison Between Physical Channel and Online Channel." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/29097179785625577528.
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碩士國立嘉義大學
行銷與流通管理研究所
93
The main purpose of this study is to clarify differences in the perceptions of channel characteristic and consumer characteristic, and the choice models of travel products between physical travel product shoppers and online travel product shoppers. In this study, we used questionnaire investigate method and collected the empirical data through two sources: We distributed questionnaires in government organizations and airport to consumers who have purchased travel products from traditional travel agencies, there were 235 valid samples collected. And we also distributed electronic questionnaires via Internet to consumers who have purchased travel products from travel websites, there were 225 valid samples collected. The five main results as follow: 1.Consumers agree that traditional travel agencies provide better “customer service” and “product quality.” 2.Consumers also agree that travel websites provide better “time saving”, “shopping convenience”, “product price”and “merchandise assortment”. 3.The online travel product shoppers are higher “perceived risk” and “purchase involvement”. 4.The main consider factors which consumers purchase travel products are price, days, residences, scenic spots, and travel agency/travel website reputation. 5.The choice model which physical travel product shoppers use most often is “weighted adding strategy”, followed by “equal weight strategy” and “nonconjunctive model”. And the choice model which online travel product shoppers use most often is “nonconjunctive model”, followed by “weighted adding strategy” and “lexicographic model”.
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Ho, Tzung-Yen, and 何宗彥. "Comparison between Direct Model and Channel Business Model in PC Industry." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/52744058806289059204.
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碩士國立臺灣大學
國際企業學研究所
94
Due to high volatility of the prices and demand/supply conditions of the electronic component industry, inventory losses could be a serious issue in the PC industry. However, Dell adopts the direct model, selling products to end users without any intermediate, to reduce inventory risks and gain a higher gross margin. Relying on its unique MIS to implement the direct model, Dell successfully establishes incredible flexibility, cost advantage and capability of rent appropriation. While everyone thinks that Dell’s business model is the only way to reduce inventory risks, Acer’s recent rising performance denies the argument. On the one hand Acer cooperates with OEM, ODM and EMS partners to accelerate turnover rate. On the other hand Acer uses of distributors and agents to fast penetrate local markets without any direct sales. Actually Acer owns nothing but the brand, and, therefore, Acer can reduce fixed cost to compete with Dell. The two business models are proven by the markets that both can work, but face some challenges. Even though Dell still gets ahead in American and European PC markets, the growth rate in the markets is not high enough to support Dell’s stock price. To make matters worse, Dell doesn’t have obvious advantages in server, NB and IT services areas. Acer’s growth rate is very high; nevertheless, Acer’s business model can be imitated by other competitors easily. To sum up, low inventory can’t promise to succeed anymore in the PC industry. After Acer solved their inventory problems, the next issue is to how expand the business model to a great extent. In conclusion, we show that different business models can achieve the same level of success in the PC industry.
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Chiu, Hsien-cheng, and 邱顯正. "Model-Based Channel Estimation for OFDM with Adaptive Model Parameter Estimation." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/12544544509736709836.
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碩士國立中央大學
通訊工程研究所
95
The OFDM model-based channel estimation technique uses the least squares method to estimate model parameters through uniformly distributed pilots in a local region. However, the regression model must use as many pilots as possible to reduce the effect of noises. Therefore, it increases storage size and computational complexity. Since model parameters has the continuity characteristics between neighboring local regions, a new model-based channel estimation method is proposed to adaptively estimate model parameters by recursive equations such that the required number of pilots is reduced, where the used number of pilots is the same as the number of model parameters and thus, the new algorithm reduces the required storage size for interpolating the symbols used in the regression model. Theoretical analyses and simulations show that better performance is obtained as well by the proposed parameter estimation method.
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Zhu, Shaozhen (Sharon), Tahereh S. Ghazaany, Steven M. R. Jones, Raed A. Abd-Alhameed, James M. Noras, Buren T. Van, and A. Merrell. "Path loss evaluation for mobile-to-mobile wireless channel." 2014. http://hdl.handle.net/10454/10835.
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NoNarrowband path loss measurements are reported for the vehicle-to-vehicle channel between a transmitting antenna 50 cm above the ground and a car-roof-mounted receiver array. Calibration procedures and measurement results are reported for typical urban, suburban and rural-motorway environments and compared with existing mobile channel models to give insight into the large-scale fading behavior in the vehicle-to-vehicle channel.
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Chiu, Hsun-Wen, and 邱絢紋. "Chinese Spell Checking Based on Noisy Channel Model." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/48295259219011665221.
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碩士國立清華大學
資訊系統與應用研究所
102
Chinese spell checking is an important component of many Chinese NLP applications, including word processors, search engines, and automatic essay rating. Compared to English, Chinese has no word boundaries, and there are various Chinese input methods that cause different kinds of typos. Therefore, it is more difficult to develop a spell checker for Chinese. In this paper, we introduce a novel method for correcting Chinese errors based on sound or shape similarity. In our approach, potential typos in a given sentence are then corrected using a channel model and a character-based language model in the noisy channel model. In the training phase, we estimate the channel probabilities for each character based on ngrams in Web corpus. At run-time, the system generates correction candidates for each character in the given sentence and selects the appropriate correction using the channel model and the language model. The experimental results show that the proposed method achieves significantly better accuracy and recall than more complicated methods in the previous work.
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Sharma, Sameer. "First order quasi static mosfet channel capacitance model." 2008. http://digital.library.okstate.edu/etd/umi-okstate-2669.pdf.
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