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Safety-critical system-of-systems need high dependability as failures can be catastrophic. Unfortunately, system dependability is sometimes sacrificed for cost, energy and performance reasons. This has been the case for the “time-triggered co-operative” (TTC) design methodology. Correct use of a TTC approach can guarantee a very high degree of reliability, robustness and predictability: incorrect...
This article described the keyboard development of AVR MCU system in detail. The keyboard mentioned in this scheme can be directly applied in single-chip based on AVR. It has wide range of applications. The article provides a schematic diagram of hardware and flow chart of software.
Simply, internet telephony is telephone network using internet as its communication media. The specific character of a telephone is its ability to make connection to the destination telephone number. So that the right term is actually internet telephony than VoIP which is more aimed to voice communication via internet, so there is no emphasizing on the ability of call directed to the destination phone...
This paper represents a performance comparison between Skype, a popular P2P-based VoIP Internet application, and tradition VoIP clients, such as Windows Live Messenger and Yahoo Messenger, which use client-server model. In order to draw a conclusion the main parameters that determine usability of the software were analyzed. These parameters are connection setup delay, end-to-end delay, jitter.
Keeping slave clocks with sub-microsecond accuracy is believed to require hardware-assistance at physical layer and network. This paper presents software-only implementations of a slave for such accuracy. Time-stamps are read in the interrupt handler and a system resource conflicts detector filters out system-inside noise. We adopted Packet Inter-Arrival based clock servo technique that has fast convergence...
Duty-cycle distortion is one of the causes of deterministic jitter. Clarification and refinement of this jitter type is presented here. The jitter-tree is then updated with the jitter types discussed. Predicting the behavior of electrical systems under stress from jitter through simulations is limited by the availability of signal sources with controllable and flexible jitter properties in the design...
This paper presents principles and results of dynamic testing of an SRAM-based FPGA using time- resolved fault injection with a pulsed laser. The synchronization setup and experimental procedure are detailed. Fault injection results obtained with a DES crypto-core application implemented on a Xilinx Virtex II are discussed.
Performance evaluation techniques for fundamental graphics algorithms and for algorithms to be used in multimedia and embedded systems are investigated. Models of computation considering only arithmetic and logic operations taken on input data are regarded as inadequate for processors with instruction-level parallelism. For experimental evaluation of graphics algorithms clock-cycle counting is found...
IEEE P1900.4 is an emerging standard for optimized radio resource utilization where cognitive radio technologies are used for efficient spectrum utilization. In this paper, we design and implement a cognitive wireless network system based on open documents of IEEE P1900.4, and evaluate its performance using UDP streaming and HTTP download. Our experiments show interesting results that total network...
Considering the high packet losses and low, varying bandwidth of GPRS/EDGE network and limited computation power of handheld devices, we present and implement a novel SVC video-on-demand system for hand-held devices over GPRS/EDGE network. For the purpose of handling varying bitrate, we propose a priority based layer switching (PLS) adaptation scheme for SVC stream, which not only performs online...
We designed and built a novel all-optical re-timing, re-amplifying, and re-shaping (3R) regeneration system based on terahertz optical asymmetric demultiplexers (TOADs) developed in our laboratory. The system is capable of parallel processing multiple wavelengths, a feature which will significantly improve the scalability of current wavelength division multiplexing (WDM) networks. Performance against...
Video-streaming can now be offered on third-generation (3G) mobile networks. Most research efforts have focused on video download. This paper presents a detailed study of challenges faced for successfully deploying applications requiring life video upload. Both subjective and objective qualities as well as the effects of mobility are analyzed on real 3G networks. Consequently, video profiles are identified...
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