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Full-Text Articles in Engineering
An Empirical Study Of Performance Benefits Of Network Coding In Multihop Wireless Networks, Y. Charlie Hu, Chih-Chun Wang
An Empirical Study Of Performance Benefits Of Network Coding In Multihop Wireless Networks, Y. Charlie Hu, Chih-Chun Wang
Department of Electrical and Computer Engineering Technical Reports
Recently, network coding has gained much popularity and several practical routing schemes have been proposed for wireless mesh networks that exploit interflow network coding for improved throughput. However, the evaluation of these protocols either assumed simple topologies and traffic patterns such as opposite flows along a single chain, or small, dense networks which have ample overhearing of each other’s transmissions in addition to many overlapping flows. In this paper, we seek to answer the fundamental question: how much performance benefit from network coding can be expected for general traffic patterns in a moderate-sized wireless mesh network? We approach this question …
Nesting Forward-Mode Ad In A Functional Framework, Jeffrey M. Siskind, Barak A. Pearlmutter
Nesting Forward-Mode Ad In A Functional Framework, Jeffrey M. Siskind, Barak A. Pearlmutter
Department of Electrical and Computer Engineering Technical Reports
We discuss the augmentation of a functional-programming language with a derivative- taking operator implemented with forward-mode automatic differentiation (AD). The primary technical difficulty in doing so lies in ensuring correctness in the face of nested invocation of that operator, due to the need to distinguish perturbations introduced by distinct invocations. We exhibit a series of implementations of a referentially- transparent forward-mode-AD derivative-taking operator, each of which uses a different non-referentially-transparent mechanism to distinguish perturbations. Even though the forward-mode-AD derivative-taking operator is itself referentially transparent, we hypothesize that one cannot correctly formulate this operator as a function definition in current pure …
Inferring Undesirable Behavior From P2p Traffic Analysis, Ruben Torres, Mohammad Hajjat, Sanjay G. Rao, Marco Mellia, Maurizio Munafo
Inferring Undesirable Behavior From P2p Traffic Analysis, Ruben Torres, Mohammad Hajjat, Sanjay G. Rao, Marco Mellia, Maurizio Munafo
Department of Electrical and Computer Engineering Technical Reports
ABSTRACT While peer-to-peer (P2P) systems have emerged in popularity in recent years, their large-scale and complexity make them difficult to reason about. In this paper, we argue that systematic analysis of traffic characteristics of P2P systems can reveal a wealth of information about their behavior, and highlight potential undesirable activities that such systems may exhibit. As a first step to this end, we present an offline and semi-automated approach to detecting undesirable behavior. Our analysis is applied on real traffic traces collected from a Point-of-Presence (PoP) of a national-wide ISP in which over 70% of the total traffic is due …
Modeling Of Spin Metal-Oxide-Semiconductor Field-Effect Transistor: A Nonequilibrium Green’S Function Approach With Spin Relaxation, Tony Low, Mark S. Lundstrom, Dmitri E. Nikonov
Modeling Of Spin Metal-Oxide-Semiconductor Field-Effect Transistor: A Nonequilibrium Green’S Function Approach With Spin Relaxation, Tony Low, Mark S. Lundstrom, Dmitri E. Nikonov
Department of Electrical and Computer Engineering Faculty Publications
A spin metal-oxide-semiconductor field-effect transistor spin MOFSET, which combines a Schottky-barrier MOFSET with ferromagnetic source and drain contacts, is a promising device for spintronic logic. Previous simulation studies predict that this device should display a very high magnetoresistance MR ratio between the cases of parallel and anitparallel magnetizations for the case of half-metal ferromagnets HMF. We use the nonequilibrium Green’s function formalism to describe tunneling and carrier transport in this device and to incorporate spin relaxation at the HMF-semiconductor interfaces. Spin relaxation at interfaces results in nonideal spin injection. Minority spin currents arise and dominate the leakage current for antparallel …
Influence Of Phonon Scattering On The Performance Of P-I-Np-I-N Band-To-Band Tunneling Transistors, Siyuranga O. Koswatta, Mark S. Lundstrom, Dmitri E. Nikonov
Influence Of Phonon Scattering On The Performance Of P-I-Np-I-N Band-To-Band Tunneling Transistors, Siyuranga O. Koswatta, Mark S. Lundstrom, Dmitri E. Nikonov
Department of Electrical and Computer Engineering Faculty Publications
Power dissipation has become a major obstacle in performance scaling of modern integrated circuits and has spurred the search for devices operating at lower voltage swing. In this letter, we study p-i-n band-to-band tunneling field effect transistors taking semiconducting carbon nanotubes as the channel material. The on current of these devices is mainly limited by the tunneling barrier properties, and phonon-scattering has only a moderate effect.We show, however, that the off current is limited by phonon absorption assisted tunneling, and thus is strongly temperature dependent. Subthreshold swings below the 60 mV/decade conventional limit can be readily achieved even at room …
Inversion Capacitance-Voltage Studies On Gaas Metal-Oxide-Semiconductor Structure Using Transparent Conducting Oxide As Metal Gate, T. Yang, Y. Liu, P. D. Ye, Y. Xuan, H. Pal, Mark S. Lundstrom
Inversion Capacitance-Voltage Studies On Gaas Metal-Oxide-Semiconductor Structure Using Transparent Conducting Oxide As Metal Gate, T. Yang, Y. Liu, P. D. Ye, Y. Xuan, H. Pal, Mark S. Lundstrom
Department of Electrical and Computer Engineering Faculty Publications
A systematic capacitance-voltage C-V study has been performed on GaAs metaloxide- semiconductor MOS structures with atomic-layer-deposited Al2O3 as gate dielectrics and indium tin oxide ITO as the metal gate. The transparent conducting ITO gate allows homogeneous photoillumination on the whole MOS capacitance area, such that one can easily observe the low-frequency LF C-V and quasistatic C-V of GaAs at room temperature. The semiconductor capacitance effect on GaAs MOS devices has also been identified and insightfully discussed based on the obtained LF C-V curves. The semiconductor capacitance effect becomes more important for devices with high-mobility channel materials and aggressively scaled high-k …