Using software components has become a widely used development technique for building large enterprise systems. However in practice, component applications are still primarily built using simple component models and a...
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Using software components has become a widely used development technique for building large enterprise systems. However in practice, component applications are still primarily built using simple component models and advanced component models offering valuable features like component nesting, multiple communication styles, behavior validation, etc. are omitted (by industry in particular). Based on our experience, such an omitting is mainly caused due to usually unbalanced semantics of these advanced features. In this paper, we present a "next-generation" component model SOFA 2.0, which in particular aims at a proper support of such advanced features.
Web services are the mainstream distributed computing technology to construct a service-oriented architecture (SOA). Over the past few years, lots of works have been carried out in comparing SOAP with binary protocols...
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Web services are the mainstream distributed computing technology to construct a service-oriented architecture (SOA). Over the past few years, lots of works have been carried out in comparing SOAP with binary protocols, such as Java RMI and CORBA. These researches show that there is a dramatic difference in the amount of encoding necessary for data transmission, when XML is compared with the binary encoding style, and all these researches have proven that SOAP, because of its reliance on XML, is inefficient compared with its peers in distributed computing. Although the performance of Web services is adequate for many important purposes, processing speed unfortunately remains to be a problem in more demanding applications. Some limitations are inherent in core features of XML: it is text based, flexible in format, and carries redundant information. Aiming at this question, a new approach to improve Web services performance is proposed. To avoid the cost brought by the traditional XML parsing and Java reflection at runtime, a specific SOAP message processor is generated dynamically for each Web service, which can create Java object for service business invoking by scanning SOAP message only once. The given experiments show that the approach can effectively improve the performance of Web service by incorporating the SOAP message processor into the SOAP engine.
In lager-scale P2P file sharing systems, peers often must interact with unknown or unfamiliar peers without the benefit of trusted third parties or authorities to mediate the interactions. The decentralized and anonym...
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ISBN:
(纸本)9783540725893
In lager-scale P2P file sharing systems, peers often must interact with unknown or unfamiliar peers without the benefit of trusted third parties or authorities to mediate the interactions. The decentralized and anonymous characteristics of P2P environments make the task of controlling access to sharing information more difficult. In this paper, we identify access control requirements and propose a trust based access control framework for P2P file-sharing systems. The model integrates aspects of trust and recommendation, fairness based participation schemes and access control schemes.
In this paper, aiming an IC implementation of a DC-DC converter with low output-voltages and large output-currents, a parallel-connected step-down DC-DC converter is designed by using a switched-capacitor (SC) techniq...
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In this paper, aiming an IC implementation of a DC-DC converter with low output-voltages and large output-currents, a parallel-connected step-down DC-DC converter is designed by using a switched-capacitor (SC) technique. The proposed SC power converter is synthesized with the charge-averaging type converters. By connecting N (= 2,3,...) converter blocks in parallel, the proposed converter can realize large current outputs and small output ripple. Furthermore, the characteristics concerning equivalent circuits, efficiency, and ripple factor are clarified by theoretical analyses since the theoretical analyses concerning the parallel-connected SC power converters have not been performed as far as authors know. The validity of the theoretical results and the circuit design is confirmed through SPICE simulations. Through the theoretical analyses and the circuit simulations, the following results are obtained: 1. the parallel-connected SC DC-DC converter can realize large current outputs and small output ripple, 2. in order to achieve high efficiency, the fluctuation of circuit elements should be minimized, and 3. by shifting the timing of the clock pulses cyclically, the ripple factor can be decreased.
In this paper, a cross-coupled type AC-DC converter for RFID tags is proposed. The converter consists of 2 charge-pump type AC-DC converters with opposite polarities. In conventional converters, the threshold voltage ...
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In this paper, a cross-coupled type AC-DC converter for RFID tags is proposed. The converter consists of 2 charge-pump type AC-DC converters with opposite polarities. In conventional converters, the threshold voltage of a diode switch causes the decrease in power efficiency. By using cross-coupled connection of CMOS switches, the proposed converter can alleviate the influence of the threshold voltage. Hence, it can achieve an AC-DC conversion with high efficiency. Furthermore, the circuit size of the proposed converter is almost the same as that of the conventional circuit. Through SPICE simulations, the following characteristics are obtained: 1. the power efficiency is more than 88 % and 2. the electric power is about 5mW when an output load is 500 Ω. Concerning the power efficiency and the ripple voltage, theoretical design formulas are derived. Furthermore, the validity of the circuit design is confirmed by experiments.
Wireless sensor networks (WSNs) have been envisioned to have a wide range of applications. The main constraint of sensor nodes is their low finite battery energy, which limits the lifetime and the quality of the netwo...
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Wireless sensor networks (WSNs) have been envisioned to have a wide range of applications. The main constraint of sensor nodes is their low finite battery energy, which limits the lifetime and the quality of the network, so that the protocols running on sensor networks must consume energy efficiently in order to achieve a longer network lifetime. One of the key problems for wireless sensor networks is the design of medium access control (MAC) protocol, in which medium access is the major consumer of sensor energy. And research on MAC protocols for WSNs has recently attracted significant attention to many applications. A self-adaptive, energy-efficient low latency (SEEL) medium access control protocol is presented for wireless sensor network. According to SEEL, each sensor node adjusts the initial contention window according to the current traffic load to reduce the collision probability while employing a fast backoff scheme to reduce the time for idle listening during backoff procedure, which reduces the energy consumption. In addition, an extended RTS/CTS scheme is employed in which the extended RTS scheme reduces active time of sensor nodes and the extended CTS scheme shortens the packet delay. Simulation results show that SEEL outperforms S-MAC and TEEM protocols.
One of the key problems for wireless sensor network (WSN) is the design of medium access control (MAC) protocol. MAC protocol controls the activity of wireless communication module of sensor nodes, which is the major ...
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One of the key problems for wireless sensor network (WSN) is the design of medium access control (MAC) protocol. MAC protocol controls the activity of wireless communication module of sensor nodes, which is the major consumer of sensor energy. The energy efficiency of MAC protocol makes a strong impact on the network performance. TDMA-based MAC protocol is inherently collision free, and can rule out idle listening since nodes know when to transmit. In this paper, we present ED-TDMA, an event driven TDMA protocol for wireless sensor network. ED-TDMA improves channel utility by changing the length of TDMA frame according to the number of source nodes, while saving energy with bitmap-assisted TDMA schedule. In addition, ED-TDMA employs intra-cluster coverage to prolong network lifetime and to improve system scalability. Simulation results show that ED-TDMA performs better for wireless sensor network with high-density deployment and low traffic.
A various terminal technology developed becoming ubiquitous society. In this paper, it is thing about device certification system and device certification method. This method is that user can use contents offering abo...
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A various terminal technology developed becoming ubiquitous society. In this paper, it is thing about device certification system and device certification method. This method is that user can use contents offering about holding many devices through registration of once in preceding descriptions many devices more detail. Therefore, because this invention achieves registration process of once without each registration process about many device that user holds, there is effect that contents use is convenient simplifying certification formality being in contents use.
Economics-driven software mining (EDSM) sifts through the repository data to extract information that could be useful for reasoning about not only the technical aspects but also the economics properties related to the...
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Economics-driven software mining (EDSM) sifts through the repository data to extract information that could be useful for reasoning about not only the technical aspects but also the economics properties related to the development and/or evolution of software systems, and in relation to the environments in which they are procured, developed, evolved and used. The objective is to provide the analyst with insights into investment decisions related to the development, maintenance, and evolution of software systems, EDSM can also assist the analyst in resource planning and utilization. In this position paper, we define EDSM, describe possible scenarios for realizing EDSM and highlight some challenges.
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