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2006 ACM SIGPLAN Symposium on Principles and Practice of Parallel programming, PPOPP'06

作者： Saha, Bratin Adl-Tabatabai, Ali-Reza Hudson, Richard L. Chi, Cao Minh Hertzberg, Benjamin Programming System Lab. Microprocessor Technology Lab. Intel Corporation Computer Architecture Lab. Stanford University Palo Alto CA

ISBN: (纸本)1595931899

Applications need to become more concurrent to take advantage of the increased computational power provided by chip level multiprocessing. Programmers have traditionally managed this concurrency using locks (mutex based synchronization). Unfortunately, lock based synchronization often leads to deadlocks, makes fine-grained synchronization difficult, hinders composition of atomic primitives, and provides no support for error recovery. Transactions avoid many of these problems, and therefore, promise to ease concurrent programming. We describe a software transactional memory (STM) system that is part of McRT, an experimental Multi-Core RunTime. The McRT-STM implementation uses a number of novel algorithms, and supports advanced features such as nested transactions with partial aborts, conditional signaling within a transaction, and object based conflict detection for C/C++ applications. The McRT-STM exports interfaces that can be used from C/C++ programs directly or as a target for compilers translating higher level linguistic constructs. We present a detailed performance analysis of various STM design tradeoffs such as pessimistic versus optimistic concurrency, undo logging versus write buffering, and cache line based versus object based conflict detection. We also show a MCAS implementation that works on arbitrary values, coexists with the STM, and can be used as a more efficient form of transactional memory. To provide a baseline we compare the performance of the STM with that of fine-grained and coarse-grained locking using a number of concurrent data structures on a 16-processor SMP system. We also show our STM performance on a non-synthetic workload - the Linux sendmail application. Copyright © 2006 ACM.

关键词： Data storage equipment

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Multi-campus collaborations among undergraduate design teams: Opportunities and challenges

Multi-campus collaborations among undergraduate design teams...

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113th Annual ASEE Conference and Exposition, 2006

作者： Zoltowski, Carla Oakes, William Myers, Barrett Purdue University United States EPICS Program Purdue University United States ASEE Department of Engineering Education Purdue University United States EPICS Program Computer Programming Technology

There are many benefits to participating in multi-campus collaborations among project-based design teams. First, students gain experience in working in a distributed design environment, which is becoming more commonplace in engineering practice. Second, collaborations offer the ability to share complementary expertise and allow student design teams to participate in projects that they would not normally be able to undertake alone. Third, collaboration among teams of multiple campuses allows for sharing of prior work and the opportunity to build upon the work to have a more significant impact. There are, however, challenges to participating in multi-campus collaborations. It is difficult for student teams to partition projects such that they can be done somewhat independently. Communication issues can be complicated by distance and the lack of face-to-face contact on a regular basis. The EPICS - Engineering Projects in Community Service - program engages undergraduate student design teams on long-term projects that solve technology-based problems for local community service organizations. There are sixteen universities with active EPICS programs in the 2005-2006 academic year. While the programs have some variation as EPICS has been integrated into each individual campus, they share basic characteristics. The existence of EPICS programs on multiple campuses has created the opportunity to collaborate across institutions. This paper will describe three models for multi-campus collaboration that have been used in EPICS. © American Society for Engineering Education, 2006.

关键词： Engineering education

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An alternative to Quiescence: Tranquility

An alternative to Quiescence: Tranquility

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International Conference on Software Maintenance (ICSM)

作者： Yves Vandewoude Peter Ebraert Yolande Berbers Theo D'Hondt Department of Computer Science Leuven Belgium Programming Technology Laboratory Brussels Belgium

This paper revisits a problem that was identified by Kramer and Magee: placing a system in a consistent state before and after runtime changes (1990). We show that their notion of quiescence as a necessary and sufficient condition for safe runtime changes is too strict and violates the black-box design principle. We introduce a weaker condition, tranquility; easier to obtain, less disruptive for the system and still sufficient to ensure application consistency. We also present an implementation of this concept in a component middleware platform

关键词： Application software Runtime Sufficient conditions computer science Middleware Web services Switches Telecommunication switching Banking Software systems

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Friends or foes An AI planning perspective on abstraction and search

Friends or foes An AI planning perspective on abstraction an...

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ICAPS 2006 - 16th International Conference on Automated Planning and Scheduling

作者： Hoffmann, Jörg Sabharwal, Ashish Domshlak, Carmel Programming Logics Group Max Planck Institute for CS 66123 Saarbrücken Germany Dept. of Computer Science Cornell University Ithaca NY 14853-7501 United States Fac. of Industrial Engr. and Management Technion Israel Institute of Technology Haifa 32000 Israel

There is increasing awareness that planning and model checking are closely related fields. Abstraction means to perform search in an over-approximation of the original problem instance, with a potentially much smaller state space. This is the most essential method in model checking. One would expect that it can also be made successful in planning. We show, however, that this is likely to not be the case. The main reason is that, while in model checking one traditionally uses blind search to exhaust the state space and prove the absence of solutions, in planning informed search is used to find solutions. We give an exhaustive theoretical and practical account of the use of abstraction in planning. For all abstraction (over-approximation) methods known in planning, we prove that they cannot improve the best-case behavior of informed search. While this is easy to see for heuristic search, we were quite surprised to find that it also holds, in most cases, for the resolution-style proofs of unsolvability underlying SAT-based optimal planners. This result is potentially relevant also for model checking, where SAT-based techniques have recently been combined with abstraction. Exploring the issue in planning practice, we find that even hand-made abstractions do not tend to improve the performance of planners, unless the attacked task contains huge amounts of irrelevance. We relate these findings to the kinds of application domains that are typically addressed in model checking.

关键词： Artificial intelligence

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InfoShield: a security architecture for protecting information usage in memory

InfoShield: a security architecture for protecting informati...

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IEEE Symposium on High-Performance computer Architecture

作者： W. Shi J.B. Fryman G. Gu H.-H.S. Lee Y. Zhang J. Yang School of Electrical and Computer Engineering Georgia Tech College of Computing Georgia Institute of Technology Programming System Lab Corporate Technology Intel Corporation USA Department of Computer Science University of Pittsburgh USA Department of Computer Science and Engineering University of California Riverside USA

Cyber theft is a serious threat to Internet security. It is one of the major security concerns by both network service providers and Internet users. Though sensitive information can be encrypted when stored in non-volatile memory such as hard disks, for many e-commerce and network applications, sensitive information is often stored as plaintext in main memory. Documented and reported exploits facilitate an adversary stealing sensitive information from an application's memory. These exploits include illegitimate memory scan, information theft oriented buffer overflow, invalid pointer manipulation, integer overflow, password stealing Trojans and so forth. Today's computing system and its hardware cannot address these exploits effectively in a coherent way. This paper presents a unified and lightweight solution, called InfoShield that can strengthen application protection against theft of sensitive information such as passwords, encryption keys, and other private data with a minimal performance impact. Unlike prior whole memory encryption and information flow based efforts, InfoShield protects the usage of information. InfoShield ensures that sensitive data are used only as defined by application semantics, preventing misuse of information. Comparing with prior art, InfoShield handles a broader range of information theft scenarios in a unified framework with less overhead. Evaluation using popular network client-server applications shows that InfoShield is sound for practical use and incurs little performance loss because InfoShield only protects absolute, critical sensitive information. Based on the profiling results, only 0.3% of memory accesses and 0.2% of executed codes are affected by InfoShield.

关键词： Information security Protection Cryptography computer security IP networks Web and internet services Nonvolatile memory Hard disks Buffer overflow Hardware

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Evaluation of the Dynamic Reconfiguration Of Mobile IPV4 agents in MANET

Evaluation of the Dynamic Reconfiguration Of Mobile IPV4 age...

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IASTED International Conference on WIRELESS SENSOR NETWORKS, Part of the Sixth IASTED International Multi-Conference on WIRELESS AND OPTICAL COMMUNICATIONS

作者： Amvame-Nze, G. Abbas, C. J. Barenco García Villalba, L.J. Faculty of Technology Electrical Eigineering School University of Brasilia - UnB Brasilia 70900 Brazil Departamento de Computacion y Tecnología de la Información Universidad Simón Bolivar Oficina MYS 213-B Apartado Postal 89.000 Caracas 1080 Venezuela Dept. Computer Systems and Programming Complutense University of Madrid Spain

This work presents a Dynamic Reconfiguration of Mobile IP Agents (DRMIPA) and failure free architecture integrated with Mobile Ad hoc Networks (MANETs). Actual infra-structured networks do not implement the Mobile IP (MIP) protocol, all MIP agents are static and the cost of having redundancy of MIP agents is often high. We propose a solution that would allow the integration of MIP with MANET. Therefore, new algorithms and messages are presented for DRMIPA in MANET and, a performance analysis is done using the Network Simulator 2 (NS2) and a real world testbed scenario.

关键词： Mobile agents

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Deleting Outliers in Robust Regression with Mixed Integer programming

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Acta Mathematicae Applicatae Sinica 2005年第2期21卷 323-334页

作者： Georgios Zioutas Antonios Avramidis Division of Computational Methods and Computer Programming General Department Faculty of Technology Aristotle University of Thessaloniki 541 24 Thessaloniki GreeceDivision of Computational Methods and Computer Programming General Department Faculty of Technology Aristotle University of Thessaloniki 541 24 Thessaloniki Greece

In robust regression we often have to decide how many are the unusualobservations, which should be removed from the sample in order to obtain better fitting for the restof the observations. Generally, we use the basic principle of LTS, which is to fit the majority ofthe data, identifying as outliers those points that cause the biggest damage to the robust ***, in the LTS regression method the choice of default values for high break down-point affectsseriously the efficiency of the estimator. In the proposed approach we introduce penalty cost fordiscarding an outlier, consequently, the best fit for the majority of the data is obtained bydiscarding only catastrophic observations. This penalty cost is based on robust design weights andhigh break down-point residual scale taken from the LTS estimator. The robust estimation is obtainedby solving a convex quadratic mixed integer programming problem, where in the objective functionthe sum of the squared residuals and penalties for discarding observations is minimized. Theproposed mathematical programming formula is suitable for small-sample data. Moreover, we conduct asimulation study to compare other robust estimators with our approach in terms of their efficiencyand robustness.

关键词： Robust regression quadratic mixed integer programming least trimmedsquares deleting outliers penalty methods

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Ambient-oriented programming

Ambient-oriented programming

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OOPSLA'05 - 20th Annual ACM Conference on Object-Oriented programming, Systems, Languages, and Applications

作者： Dedecker, Jessie Van Cutsem, Tom Mostinckx, Stijn D'Hondt, Theo De Meuter, Wolfgang Programming Technology Laboratory Department of Computer Science Vrije Universiteit Brussel Belgium

A new field in distributed computing, called Ambient In-telligence, has emerged as a consequence of the increasing availability of wireless devices and the mobile networks they induce. Developing software for such mobile networks is extremely hard in conventional programming languages because the network is dynamically defined. This hardware phenomenon leads us to postulate a suite of characteristics of future Ambient-Oriented programming languages. A simple re ective programming language kernel, called AmbientTalk, that meets these characteristics is subsequently presented. The power of the re ective kernel is illustrated by using it to conceive a collection of high level tentative ambient-oriented programming language features. © 2005 ACM.

关键词： Wireless networks

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AmbientOriented programming in AmbientTalk: Combining mobile hardware with simplicity and expressiveness

AmbientOriented Programming in AmbientTalk: Combining mobile...

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OOPSLA'05 - 20th Annual ACM Conference on Object-Oriented programming, Systems, Languages, and Applications

作者： Dedecker, Jessie Cutsem, Tom Van Mostinckx, Stijn De Meuter, Wolfgang D Hond, Theo Programming Technology Laboratory Department of Computer Science Vrije Universiteit Brussel Belgium

A new field in distributed computing, called Ambient Intelligence, has emerged as a consequence of the increasing availability of wireless devices and the mobile networks they induce. Developing software for such mobile networks is extremely hard in conventional programming languages because the network is dynamically defined. We demonstrate a new distributed programming language named AmbientTalk, a research vehicle to experiment with expressive high-level language constructs for Ambient-Oriented programming. © 2005 ACM.

关键词： High level languages

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Component + aspect = An extensible and adaptable system software

Component + aspect = An extensible and adaptable system soft...

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2005 International Conference on Software Engineering Research and Practice, SERP'05

作者： Netinant, Paniti Department of Computer Science Bangkok University Bangkok Thailand Concurrent Programming Research Group Computer Science Department Illinois Institute of Technology Chicago IL United States

ISBN: (纸本)9781932415490

The benefits associated with separation of concerns are well established. Aspect-Orientation is a methodology that aims at separating components and aspects from the early stages of the software life cycle, and using techniques to combining them together at the implementation phase. Componentbased programming systems have shown themselves to be a natural way of constructing extensible software. Well-defined interfaces, encapsulation, late binding and polymorphism promote extensibility, yet despite this synergy, components have not been widely employed at the systems level. This is primarily due to the failure of existing component technologies to provide the protection and performance required of systems software. In this paper we identify the requirements for a component system to support extensions, and describe an extensibility and adaptability in the design of system software. We discuss an aspect-oriented framework that can simplify system design by expressing it at a higher level of abstraction. Our work concentrates on how to achieve a higher separation of aspects, components, and layers from each other. Our goal is to achieve a better design model for system software in terms of extensibility, reuse and adaptability.

关键词： computer software reusability

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