7975007
Optimum design of very low distortion class E power amplifiers
In this paper, the optimum design of a class E power amplifier with resonant tank being symmetrically driven by two class E circuits is studied. The optimally designed symmetrical class E circuit has extremely low harmonic distortion, and the load matching network (if required) is non-critical and can be designed with ease. Practical steady-state design equations are derived and graphically presented. Experimental circuits are constructed for distortion evaluation.
8528863
Stability Analysis of RED Gateway with Multiple TCP Reno Connections
It has been observed that a bottleneck random early detection (RED) gateway becomes oscillatory when regulating a flow in multiple TCP connections. The stability boundary of the TCP-RED system depends on various network parameters, making the adjustment of the RED gateway a difficult task. Based on a fluid-flow model, analytical conditions were formulated that describe the stable boundary of the RED gateway depending on the number of TCP Reno connections. The proposed model accurately generates a stability boundary surface in a four dimensional space, which facilitates the adjustment of parameters for stable operation of the RED gateway. The accuracy of the analytical results has been verified using the ns-2 network simulations.
18516994
Fast analytical approach to finding steady-state waveforms for power electronics circuits using orthogonal polynomial basis functions
This paper describes a general analytical procedure for steady-state waveform analysis of power electronics circuits using orthogonal polynomials. The proposed method exploits the time-domain piecewise property of power electronics circuits as well as the orthogonality of certain polynomials in order to maximize the accuracy and computational efficiency. This new analytical approach can provide a fast means to obtain improved and more robust solutions of steady-state waveforms of power electronics circuits
28398925
Object Assisted Video Coding for Video Conferencing System
An object-based video coding for video conferencing system is proposed. There are two main processes: segmentation process and face detection process. The segmentation process is used to segment each frame of a video sequence into two non-overlapping regions, namely foreground and background. A novel face detection technique based on chrominance and the contour of the segmented region is applied to the foreground region. Smaller quantization step is used for the facial region to improve viewer's perception while a larger quantization step is used for the background to compensate the coding efficiency. The remaining regions are kept in normal coding quality to prevent degradation of important information other than the facial regio.
10156011
On a service-oriented approach for an engineering knowledge desktop
Increasingly, manufacturing companies are shifting their focus from selling products to providing services. As a result, when designing new products, engineers must increasingly consider the life cycle costs in addition to any design requirements. To identify possible areas of concern, designers are required to consult existing maintenance information from identical products. However, in a large engineering company, the amount of information available is significant and in wide range of formats. This paper presents a prototype knowledge desktop suitable for the design engineer. The Engineering Knowledge Desktop analyses and suggests relevant information from ontologically marked-up heterogeneous web resources. It is designed using a Service-Oriented Architecture, with an ontology to mediate between Web Services. It has been delivered to the user community for evaluation.
7455983
A study of the short message service of a nationwide cellular network
In recent years, cellular networks have experienced an astronomical increase in the use of Short Message Service (SMS), making it a popular communication means for inter-personal as well as content provider-to-person usage. Yet little is known about the traffic and message user behavior in real SMS systems. In this paper, we present a measurement study of SMS based on traces collected from a nationwide cellular carrier during a three-week period. We characterize message traffic at both the message level and the conversation thread level. We also examine the "store-and-forward" mechanism of SMS and present initial measurements on how messages are actually delivered.
37834604
Development of Hybrid Optimisation Techniques Based on Genetic Algorithms and Simulated Annealing
6329891
Design patterns for lazy evaluation
We propose an object-oriented (OO) formulation and implementation of lazy/delayed evaluation by reusing and extending an existing linear recursive structure (LRS) framework with the help of the strategy, decorator and factory design patters. The result is a robust, flexible framework that can handle both infinite and finite lists and to which existing algorithms for finite lists can be applied without modification. The OO techniques used to develop this model are effective tools for teaching abstraction and design of data structures.
12096592
Lightweight Agent Framework for Camera Array Applications
This paper describes a lightweight middleware agent framework (LAF) for coordinating a large array of computers with attached cameras to construct high resolution video-rate image sequences. Compared to existing camera middleware, LAF provides more than a remote sensor access API. The use of an agent framework allows reconfigurable and transparent access to cameras, as well as software agents capable of intelligent processing. It also eases maintenance by encouraging code reuse. Other features include an automatic discovery mechanism at startup, and multiple language bindings. Performance tests showed the lightweight nature of the framework while validating its correctness and scalability. Two different camera agents were implemented to provide access to a large array of distributed cameras. Correct operation of these camera agents was confirmed via several image processing agents.