Location Awareness—Improving Distributed Multimedia Communication

Multimedia creation and consumption is highly intensive and makes up the majority of Internet traffic nowadays. End-users are able to share their digital content with each other and to build communities based on interests, which often differ drastically according to location. Distributing these media using a central server can be quite expensive for a content provider. Distributed (peer-to-peer like) systems share costs evenly among participants. Thus, distributed multimedia systems will be more important in the future. The global distribution of end-users aggravates high-quality delivery of multimedia content. In this paper, we argue that geographical location-awareness greatly helps distributed multimedia communication. It increases the quality of multimedia content delivery and at the same time satisfies the growing need for more personalized, location-based services. In this paper, as a proof of concept, we introduce an overlay structure for distributed multimedia systems (and similar systems), which is location-aware and uses the locations of its nodes to optimize node-to-node communication for performance and delay. At the same time, the system enables location-based services.     

Silicon Organic Hybrid Technology—A Platform for Practical Nonlinear Optics

A cost-effective route to build electrically as well as optically controlled modulators in silicon photonics is reviewed. The technology enables modulation at bit rates beyond 100 Gbit/s. This platform relies on the well-established silicon-based complementary metal-oxide-semiconductor processing technology for fabricating silicon-on-insulator (SOI) waveguides, while an organic cladding layer adds the required nonlinearity. The strength of this hybrid technology is discussed, and two key devices in communications are exemplarily regarded in more detail. The first device demonstrates demultiplexing of a 120 Gbit/s signal by means of four-wave mixing in a slot-waveguide that has been filled with a highly nonlinear chi⁽³⁾-organic material. The second device is a 100 Gbit/s/1 V electrooptic modulator based on a slow-light SOI photonic crystal covered with a chi⁽²⁾ -nonlinear organic material.     

改进晶片键合质量可靠性的综合分析方法

对提高半导体工业键合工艺可靠性进行实例研究.首先进行键合工艺技术分析,采用了一种定性方法来辨识故障.实验证实,改进的键合工艺可以降低关键事件对晶片偏转的影响.综合了控制与可靠性工程方面的知识,提出了一种混合的分析方法.     

Fibre to the home—The passive way

Passive optical networks are an attractive alternative to copper for basic POTS delivery in the near term. Since PONs provide a direct photonic path between the exchange and the customer they offer the maximum opportunities for network evolution by allowing services to evolve naturally and independently in the market place.     

Router Management—The SNMP Way

As LANS multiply across corporations, distributed processing has outgrown the ‘promising’ stage and has become an equal, both in scope of application and commercial potential, to the centralized computing approach.     

APPN — The Control Point

In this third article in the series on managing APPN networks we will go into more details about the APPN Control Point, which resides in every APPN Network and End Node, coordinating the exercising of all APPN Services, and being responsible for all local management functions.     

Getting the best possible deal by helping—not pleasing—the neutral

There's more that parties can do to help themselves in mediation. Veteran Evanston, Ill., neutral Stephen B. Goldberg describes how parties can work more effectively with the neutrals they hire to help them close cases and deals     

Improving Wireless TCP Throughput by a Novel TCM-Based Hybrid ARQ

A novel hybrid ARQ (HARQ) scheme using a concatenated two-state trellis-coded modulation (CT-TCM) code is proposed for improving wireless TCP throughput. A distinguished feature of the proposed scheme is that the heavily punctured TCM codes are used for retransmissions of the corrupted data block, which are combined at the receiver with the previously received sequences of the same data block for decoding. By this method, significantly improved coding gain and efficient spectrum utilization can be achieved with very low complexity. A Markov model is developed to evaluate TCP throughput over the proposed HARQ in wireless link. By both analysis and simulation, we demonstrate that compared with other existing TCM-based ARQ schemes, significant improvement of TCP throughput over wireless links is achieved by the proposed CT-TCM HARQ while smaller buffer size is required at the access point.     

Two-carrier conduction in MOS tunnel—Oxides II—Theory

Analytic expressions describing electron and hole current flow in the metal/tunnel—oxide/n-silicon structure are derived. In the particular approach that is taken, the tunneling barrier presented by the SiO₂ layer is treated using a “thick-oxide” MOS model; i.e. a trapezoidal tunneling barrier is used. Rather than assume a constant tunneling probability, the dependence of the tunneling barrier on applied bias and on the minority carrier density at the semiconductor surface is also included. Calculations based on the resultant equations are found to be in good agreement with experimental observations, and to correctly predict the “current-multiplication” effect that occurs under conditions of minority carrier injection to the Si---SiO₂ interface [1].

The derived equations are used to simulate device behaviour under various experimental conditions, including the effects of minority carrier injection, non-zero flatband voltage, and changes in substrate doping concentration and temperature. In addition, device parameters such as barrier height and carrier effective mass are also investigated with regard to their effect on the resultant electron and hole tunneling currents.     

Optical networks—the electro-optic reality

A general overview of the current status and future trends in optical networking is given. Special attention is given to the coexistence of optical and electronic technologies in telecommunications networks. After reviewing the advantages of both technologies, their use in different network areas is discussed. A critical survey of current and new transport technologies in optical core and metropolitan networks is given, including SDH/SONET and its enhancements, OTN, RPR, and Ethernet. The current status and prospects for photonic switching are briefly presented. The paper is concluded with an overview of the control plane for optical transport networks.     

Broadband Island interconnection via satellite—performance analysis for the race II—catalyst project

The use of communication satellites as a possible way of offering broadband island interconnectivity appears to be a very attractive option, as it will enable the provision of an all-digital, transparent service to a number of ATM islands spanning a wide area, accommodating efficiently a variety of traffic demands. The CATALYST Project (RACE II/R2074) is an attempt to demonstrate the applicability and compatibility of satellite technology with the terrestrial BISDN. In this paper we present an overview of the project and focus on an initial study of the expected user performance through the CATALYST network. Our analysis is based upon mathematical and simulation models and describes the end-system to end-system transfer delay for given message lengths. The protocol profiles assume a mix of Novell NetWare and Network File System client/server architectures, which are supported by either the IEEE 802.3/Ethernet or fibre distributed data interface LANs, which are themselves linked via LAN/ATM/satellite interface units. Areas of further investigation, and the implication of our analysis on the actual network architecture, are discussed.     

Fuzzy Gain-Scheduling Proportional–Integral Control for Improving Engine Power and Speed Behavior in a Hybrid Electric Vehicle

With the increased emphasis on improving fuel economy and reducing emissions, hybrid electric vehicles (HEVs) have emerged as very strong candidates to achieve these goals. The power-split hybrid system, which is a complex hybrid powertrain, exhibits great potential to improve fuel economy by determining the most efficient regions for engine operation and thereby high-voltage (HV) battery operation to achieve overall vehicle efficiency optimization. To control and maintain the actual HV battery power, a sophisticated control system is essential, which controls engine power and thereby engine speed to achieve the desired HV battery maintenance power. Conventional approaches use proportional-integral (PI) control systems to control the actual HV battery power in power-split HEV, which can sometimes result in either overshoots of engine speed and power or degraded response and settling times due to the nonlinearity of the power-split hybrid system. We have developed a novel approach to intelligently controlling engine power and speed behavior in a power-split HEV using the fuzzy control paradigm for better performances. To the best of our knowledge, this is the first reported use of the fuzzy control method to control engine power and speed of a power-split HEV in the applied automotive field. Our approach uses fuzzy gain scheduling to determine appropriate gains for the PI controller based on the system's operating conditions. The improvements include elimination of the overshoots as well as approximate 50% faster response and settling times in comparison with the conventional linear PI control approach. The improved performances are demonstrated through simulations and field experiments using a ford escape hybrid vehicle.