the IA-64 architecture provides a rich set of features to aid the compiler in exploiting instruction- level parallelism to achieve high performance. Currently, GCC is a widely used open-source compiler for IA-64, but ...
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ISBN:
(纸本)3540296433
the IA-64 architecture provides a rich set of features to aid the compiler in exploiting instruction- level parallelism to achieve high performance. Currently, GCC is a widely used open-source compiler for IA-64, but its performance, especially its floating-point performance, is poor compared to that of commercial compilers because it has not fully utilized IA-64 architectural features. Since late 2003 we have been working on improving the performance of GCC on IA-64. this paper reports four improvements on enhancing its floating-point performance, namely alias analysis for FORTRAN (its part for COMMON variables already committed in GCC 4.0.0), general induction variable optimization, loop unrolling and prefetching arrays in loops. these improvements have significantly improved the floating-point performance of GCC on IA-64 as extensively validated using SPECfp2000 and NAS benchmarks.
Current security systems are designed to prevent foreseeable attacks. those security systems do not prevent effectively the more emergent types of attacks, like a botnet, whose presence and behavior is difficult to pr...
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Current security systems are designed to prevent foreseeable attacks. those security systems do not prevent effectively the more emergent types of attacks, like a botnet, whose presence and behavior is difficult to predict. In order to predominate those types of attacks, we advocate an adaptive security approach based on the animal immune system. But since those sophisticated attacks can also be directed at the security systemsthemselves, leading to computer immunodeficiency, like HIV, in this paper we propose a protocol that protects the immune system itself this approach discriminates between attacks on the security systems, which are part of the computer immune system, and attacks on other vital computersystems in an information infrastructure.
A reduced-complexity algorithm and its systolic architecture are presented for computation of the discrete cosine transform. the proposed scheme not only leads to a fully-pipelined regular and modular hardware, but al...
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this paper presents thU-SOC, a new methodology and tool dedicated to explore design space by executing full-scale SW application code on the transaction level models of the SoC platform. the SoC platform supports alte...
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ISBN:
(纸本)3540296433
this paper presents thU-SOC, a new methodology and tool dedicated to explore design space by executing full-scale SW application code on the transaction level models of the SoC platform. the SoC platform supports alternative Transaction Level Models (TLMs), bus-functional model and bus-arbitration model, which enables it to cooperate with different levels of hardware descriptions. So, users are only required to provide functional descriptions to construct a whole cycle-accurate system simulation for a broad design space exploration in the architecture design. When the architecture is determined, the high-level descriptions can be replaced by RTL-level descriptions to accomplish the system verification, and the interface between the tool and the descriptions is unmodified. Moreover, thU-SOC integrates some behavior models of necessary components in a SoC system, such as ISS (Instruction- Set Simulator) simulator of CPU, interrupt controller, bus arbiter, memory controller, UART controller, so users can focus themselves on the design of the target component. the tool is written in C++ and supports the PLI (Programming Language Interface), therefore its performance is satisfying and different kinds of hardware description languages, such as System-C, Verilog, VHDL and so on, are supported.
Current commercial Earth Observation satellites have very restricted image processing capabilities on-board. they mostly operate according to a 'store-and forward' mechanism, where the images are stored on-boa...
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ISBN:
(纸本)3540296433
Current commercial Earth Observation satellites have very restricted image processing capabilities on-board. they mostly operate according to a 'store-and forward' mechanism, where the images are stored on-board after being acquired from the sensors and are downlinked when contact with a ground station occurs. However, in order for disaster monitoring satellite missions to be effective, there is a need for automated and intelligent image processing onboard. In fact, the need for increasing the automation on-board is predicted as one of the main trends for future satellite missions. the main factors that hold back this concept are the limited power and computing resources on-board the spacecraft. this paper reviews existing image processing payloads of earth observing small satellites. An autonomous change detection system is proposed to demonstrate the feasibility of implementing an intelligent system on-board a small satellite. Performance results for the proposed intelligent imaging system are estimated, scaled and compared to existing hardware that are being used in the SSTL DMC satellite platform.
there are very few studies done in dealing withcomputer viruses in Malaysia. By realizing that, this research paper is done in managing of virus problem among ICT users in Malaysia. Firstly, this research is establis...
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there are very few studies done in dealing withcomputer viruses in Malaysia. By realizing that, this research paper is done in managing of virus problem among ICT users in Malaysia. Firstly, this research is establishing the existence of the problem through a questionnaire survey, which was carried out specifically at Klang Valley and Putrajoya in Malaysia. then a study was made on classifying virus, studying their symptoms and behaviour withthe aim of controlling its propagation by studying their known features. the ECOVP (Efficient Control of Virus Propagation) system that was developed is capable of educating users in handling computer virus incidents and at the same time helps to control computer virus propagation.
Data cache hit ratio has a major impact on execution performance of programs by effectively reducing average data access time. Prefetching mechanisms improve this ratio by fetching data items that shall soon be requir...
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ISBN:
(纸本)3540296433
Data cache hit ratio has a major impact on execution performance of programs by effectively reducing average data access time. Prefetching mechanisms improve this ratio by fetching data items that shall soon be required by the running program, Software-driven prefetching enables application-specific policies and potentially provides better results in return for some instruction overhead, whereas hardware-driven prefetching gives little overhead, however general-purpose processors cannot adapt to the specific needs of the running application. In the application-specific processors that we develop customized to an object-oriented application, we implement application-specific hardware prefetching to benefit from both worlds. this prefetching policy prefetches all data items that shall be unconditionally accessed by a class method when the class method is called. We mathematically analyze this mechanism and present its simulation results using some object-oriented benchmarks. Simulation results in absence and presence of the proposed prefetching mechanism confirm the theoretical results and show that on average, the miss ratio is reduced by 73%.
In the optical burst-switching (OBS) system, IP-over-WDM network has been paid great attention due to its bandwidth efficiency and adaptive traffic load accommodation. However, the abrupt burst for large traffic loads...
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ISBN:
(纸本)0780386019
In the optical burst-switching (OBS) system, IP-over-WDM network has been paid great attention due to its bandwidth efficiency and adaptive traffic load accommodation. However, the abrupt burst for large traffic loads will result in unbearable performance degradation in the traditional JET network To combat withthe load sensitivity, a wavelength-routed OBS (WR-OBS) network architecture was confirmed effective. In this paper, we have proposed a distributed control WR-OBS network architecture combining JET protocol with a two-way reservation method. Based on this architecture, two new resource reservation protocols are compared by evaluating performance. computer simulation results demonstrate that improvement of burst blocking probability can be achieved in backward reservation protocol and all these two control protocols outperform traditional JET OBS network.
there is trend towards networked and distributed hardware reconfigurable systems, complicating the design process at the system-level. this paper will provide a solution to the problem of design space exploration for ...
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ISBN:
(纸本)0780387368
there is trend towards networked and distributed hardware reconfigurable systems, complicating the design process at the system-level. this paper will provide a solution to the problem of design space exploration for such embedded systems of the next generation. We will show the problems occurring while exploring the design space at the system-level, leading to new properties for valid implementations. the novelty of this approach lies in the support of explicit communication modeling and time-multiplexed architecture modeling in a single model. the proposed design space exploration is based on Evolutionary Algorithms and a new slack-based list scheduler.
作者：
Wang, MeilingLiu, LeiJilin Univ
Coll Comp Sci & Technol Minist Educ Key Lab Symbol Computat & Knowledge Engn Changchun 130012 Peoples R China
Dynamic Description Logic (DDL) can support boththe static and dynamic knowledge representation, thus this paper introduces a kind of Software architecture (SA) Model based on DDL, the purpose of which is to facilita...
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ISBN:
(纸本)3540400567
Dynamic Description Logic (DDL) can support boththe static and dynamic knowledge representation, thus this paper introduces a kind of Software architecture (SA) Model based on DDL, the purpose of which is to facilitate the description of each part of SA as well as the constraints between them. In addition, the model also supports the detection of the consistency problems existed in dynamic architecture. In the end, the mapping from SA to DLL is discussed, and an example of a complete architecture model of Pipeline-Filter style is described.
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