Design and Implementation of Optical Signal Reinstatement Technique for High DPSK RZ Transceiver Scheme

Wireless Personal Communications - Optical signal reinstatement (OSR) is a common technique used in high-speed communication systems. OSR can be achieved using various techniques such as;...     

AKH-NFIS: Adaptive Krill Herd Network Fuzzy Inference System for Mobile Robot Navigation

Wireless Personal Communications - Mobile robot navigation has been a current issue in the most recent two decades. Mobile robots are necessary to explore in obscure and dynamic situations. To...     

Non-Cooperative Games for Service Differentiation in CDMA Systems

In this paper, we address the problem of user-class based service differentiation in CDMA networks. Users are categorized into three classes who get differentiated services based on their expected quality of service (QoS) from the service provider and the price they are willing to pay. We adopt a game theoretic approach for allocating resources through a two-step process. During a service admission, resource distribution is determined for each class. Then, the resource allocated to each class is distributed among the active users in that class. We devise a utility function for the providers which considers the expected revenue and the probability of users leaving their service provider if they are not satisfied with the service. Our model demonstrates how power can be controlled in a CDMA network to differentiate the service quality. Also, we show the impact of admitting high paying users on other users. Mainak Chatterjee received his Ph.D. from the department of Computer Science and Engineering at The University of Texas at Arlington in 2002. Prior to that, he completed his B.Sc. with Physics (Hons) from the University of Calcutta in 1994 and M.E. in Electrical Communication Engineering from the Indian Institute of Science, Bangalore, in 1998. He is currently an Assistant Professor in the department of Electrical and Computer Engineering at the University of Central Florida. His research interests include economic issues in wireless networks, applied game theory, resource management and quality-of-service provisioning, ad hoc and sensor networks, CDMA data networking, and link layer protocols. He serves on the executive and technical program committee of several international conferences. Haitao Lin received the BE degree in radio engineering from Southeast University, Nanjing, China, in 1996, the MS degree in computer applications from the Beijing University of Posts and Telecommunications, Beijing, China, in 2000, and Ph.D. in Computer Science and Engineering from The University of Texas at Arlington in 2004. He is currently with Converged Multimedia Services System Engineering at Nortel, Richardson, Texas. His research interests include wireless network performance evaluation and enhancement, wireless link adaptation, wireless network resource management, and applied game theory. Sajal K. Das received B.S. degree in 1983 from Calcutta University, M.S. degree in 1984 from Indian Institute of Science, Bangalore, and Ph.D. degree in 1988 from University of Central Florida, Orlando, all in Computer Science. He is currently a Professor of Computer Science and Engineering and also the Founding Director of the Center for Research in Wireless Mobility and Networking (CReWMaN) at the University of Texas at Arlington (UTA). Prior to 1999, he was a professor of Computer Science at the University of North Texas (UNT), Denton where he founded the Center for Research in Wireless Computing (CReW) in 1997, and also served as the Director of the Center for Research in Parallel and Distributed Computing (CRPDC) during 1995–97. Dr. Das is a recipient of the UNT Student Association's Honor Professor Award in 1991 and 1997 for best teaching and scholarly research; UNT's Developing Scholars Award in 1996 for outstanding research; UTA's Outstanding Faculty Research Award in Computer Science in 2001 and 2003; and the UTA College of Engineering Research Excellence Award in 2003. He is also frequently invited as a keynote speaker at international conferences and symposia. Dr. Das' current research interests include mobile wireless communications, resource and mobility management in wireless networks, mobile and pervasive computing, wireless multimedia, ad hoc and sensor networks, mobile internet architectures and protocols, distributed and grid computing, performance modeling and simulation. He has published over 350 research papers in these areas in international journals and conferences, directed numerous industry and government funded projects, and holds five US patents in wireless mobile networks. He received four Best Paper Awards in the ACM MobiCom'99, ICOIN'01, ACM MSWiM'00, and ACM/IEEE PADS'97. He as the Editor in Chief of the Pervasive and Mobile Computing (PMC) journal and also as an Associate Editor of IEEE Transactions on Mobile Computing, ACM/Kluwer Wireless Networks, Parallel Processing Letters, Journal of Parallel, Distributed and Emerging Systems. He served as General Chair of IEEE WoWMoM'05, PerCom'04, IWDC'04, MASCOTS'02, ACM WoWMoM'00-02; General Vice Chair of IEEE PerCom'03, ACM MobiCom'00 and IEEE HiPC'00-01; Program Chair of IWDC'02, WoWMoM'98-99; TPC Vice Chair of ICPADS'02; and as TPC member of numerous IEEE and ACM conferences. He is Vice Chair of the IEEE Computer Society's TCPP and TCCC Executive Committees.     

Social‐based reputation‐aware data forwarding for improved multicast delivery in the presence of selfish nodes in DTNs

Delay/disruption tolerant networks (DTNs) are potentially applicable in the challenged scenarios like post‐disaster environments. In such networks, data forwarding generally relies on the mutual cooperation of the nodes. However, in reality, despite the availability of necessary resources for data forwarding, a node could misbehave by dropping messages received from other nodes with whom it has no strong social ties. Such a node is called a socially selfish node, which would cause a poor delivery ratio in the network. In this paper, we aim to address the problem of multicast data forwarding in the presence of such selfish nodes, by means of efficient relay selection in DTNs. First, we define a realistic reputation model, in contrast to existing models, to define the socially selfish/misbehaving nodes in the network. Further, a game‐theoretic analysis is carried out that implies data forwarding cost is also an influential parameter in handling selfishness/misbehavior. Subsequently, the problem is formulated as a constrained optimization problem, which is NP hard. Therefore, a heuristic is proposed by combining the reputation of a node and the cost of message forwarding to appropriately identify relay nodes, thus improve the performance of the multicast message delivery in the network. We utilize a social metric, centrality to minimize the message forwarding cost in terms of the number of relay nodes. Finally, the comparative performance evaluation in ONE simulator with practical scenarios shows the superiority of the proposed scheme over the other prominent schemes.     

Flexible hybrid WDM/TDM PON architectures using wavelength selective switches

For building an optical access network, we propose some new hybrid WDM/TDM passive optical network (PON) architectures that use wavelength selective switches (WSSs) at the remote node to improve flexibility, data security and power budget. Through simulations we demonstrate that the switching capabilities of a WSS can provide additional gains in terms of wavelength usage by a better statistical multiplexing. Several WSS-based hybrid WDM/TDM PON variants are proposed and assessed. These architectures are also compared with the more commonly used hybrid WDM/TDM PONs consisting of power splitters and/or arrayed wavelength gratings (AWGs), in terms of cost and power budget.     

Interfacial Engineering of Bifunctional Niobium (V)-Based Heterostructure Nanosheet Toward High Efficiency Lean-Electrolyte Lithium–Sulfur Full Batteries

High-efficiency lithium–sulfur (Li–S) batteries depend on an advanced electrode structure that can attain high sulfur utilization at lean-electrolyte conditions and minimum amount of lithium. Herein, a twinborn holey Nb₄N₅–Nb₂O₅ heterostructure is designed as a dual-functional host for both redox–kinetics–accelerated sulfur cathode and dendrite-inhibited lithium anode simultaneously for long-cycling and lean-electrolyte Li–S full batteries. Benefiting from the accelerative polysulfides anchoring–diffusion–converting efficiency of Nb₄N₅–Nb₂O₅, polysulfide-shutting is significantly alleviated. Meanwhile, the lithiophilic nature of holey Nb₄N₅–Nb₂O₅ is applied as an ion-redistributor for homogeneous Li-ion deposition. Taking advantage of these merits, the Li–S full batteries present excellent electrochemical properties, including a minimum capacity decay rate of 0.025% per cycle, and a high areal capacity of 5.0 mAh cm⁻² at sulfur loading of 6.9 mg cm⁻², corresponding to negative to positive capacity ratio of 2.4:1 and electrolyte to sulfur ratio of 5.1 µL mg⁻¹. Therefore, this work paves a new avenue for boosting high-performances Li–S batteries toward practical applications.     

Channel Assignment Strategies for Multiradio Wireless Mesh Networks: Issues and Solutions

Next-generation wireless mobile communications will be driven by converged networks that integrate disparate technologies and services. The wireless mesh network is envisaged to be one of the key components in the converged networks of the future, providing flexible high- bandwidth wireless backhaul over large geographical areas. While single radio mesh nodes operating on a single channel suffer from capacity constraints, equipping mesh routers with multiple radios using multiple nonoverlap- ping channels can significantly alleviate the capacity problem and increase the aggregate bandwidth available to the network. However, the assignment of channels to the radio interfaces poses significant challenges. The goal of channel assignment algorithms in multiradio mesh networks is to minimize interference while improving the aggregate network capacity and maintaining the connectivity of the network. In this article we examine the unique constraints of channel assignment in wireless mesh networks and identify the key factors governing assignment schemes, with particular reference to interference, traffic patterns, and multipath connectivity. After presenting a taxonomy of existing channel assignment algorithms for WMNs, we describe a new channel assignment scheme called MesTiC, which incorporates the mesh traffic pattern together with connectivity issues in order to minimize interference in multi- radio mesh networks.     

Floating Point CGRA based Ultra-Low Power DSP Accelerator

Journal of Signal Processing Systems - Coarse Grained Reconfigurable Arrays (CGRAs) are emerging as energy efficient accelerators providing a high grade of flexibility in both academia and...     

Assessment of organizational reliability capability

A reliability capability assessment process can assist OEMs and system integrators in assessing prospective suppliers for their ability to design and manufacture reliable products before they are delivered for use, and on an ongoing basis, help a company in identifying shortcomings in its reliability program, which can be rectified by subsequent improvement actions. The assessment can also help to establish reliability management practices for use by designers, suppliers, customers, and independent authorities. The assessment method may be used to evaluate the reliability capability of all types of electronics-related industries that perform activities influencing the reliability of a product. It can produce increased customer satisfaction, provide competitive opportunities, and shorten the product development cycle. In summary, a reliability capability assessment can be used for: 1) specifying or planning reliability practices if product development is implemented internally; 2) evaluating reliability practices to determine the extent to which a supplier is capable of providing a product that meets the reliability requirements/needs; and 3) improving reliability practices if the current reliability practices have been evaluated and improvement is desired or required.     

Routing Correlated Data in Wireless Sensor Networks: A Survey

Sensory data gathered from sensor nodes in physical proximity tend to exhibit strong correlation. To minimize such redundancy and hence curtail the load in wireless sensor networks with a goal to conserve energy, effective in-network fusion schemes have been extensively proposed in the literature. To this end, routing schemes supporting data fusion are extremely important as they dictate where and when sensory data streams shall intersect with each other and thus fusion will be performed. In this article we briefly articulate this problem and classify recently proposed routing schemes supporting data fusion in wireless sensor networks into three categories: routing-driven, coding-driven, and fusion-driven. We also give an overview of various algorithms in each category by summarizing their design approaches, benefits, and drawbacks.