this book constitutes the refereed proceedings of the 35thconference on currenttrends in theory and practice of computerscience, SOFSEM 2009, held in pindleruv Mln, Czech Republic, in January 2009. the 49 revised f...
ISBN:
(数字)9783540958918
ISBN:
(纸本)9783540958901
this book constitutes the refereed proceedings of the 35thconference on currenttrends in theory and practice of computerscience, SOFSEM 2009, held in pindleruv Mln, Czech Republic, in January 2009. the 49 revised full papers, presented together with 9 invited contributions, were carefully reviewed and selected from 132 submissions. SOFSEM 2009 was organized around the following four tracks: Foundations of computerscience; theory and practice of Software Services; Game theoretic Aspects of E-commerce; and Techniques and Tools for Formal Verification.
We show that the interactive knapsack heuristic optimization problem is APX-hard. Moreover, we discuss the relationship between the interactive knapsack heuristic optimization problem and some other knapsack problems....
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Programmers rely on programming idioms, design patterns, and workaround techniques to make up for missing programming language support. Evolving languages often address frequently encountered problems by adding langua...
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ISBN:
(纸本)9783642112652
Programmers rely on programming idioms, design patterns, and workaround techniques to make up for missing programming language support. Evolving languages often address frequently encountered problems by adding language and library support to subsequent releases. By using new features, programmers can express their intent more directly. As new concerns, such as parallelism or security, arise, early idioms and language facilities can become serious liabilities. Modern code sometimes benefits from optimization techniques not feasible for code that uses less expressive constructs. Manual source code migration is expensive, time-consuming, and prone to errors. In this paper, we present the notion of source code rejuvenation, the automated migration of legacy code and very briefly mention the tools we use to achieve that. While refactoring improves structurally inadequate source code, source code rejuvenation leverages enhanced program language and library facilities by finding and replacing coding patterns that can be expressed through higher-level software abstractions. Raising the level of abstraction benefits software maintainability, security, and performance.
the proceedings contain 22 papers. the topics discussed include: equivalence-checking with infinite-state systems: techniques and results;database support for multisource multiresolution scientific data;semantic annot...
ISBN:
(纸本)354000145X
the proceedings contain 22 papers. the topics discussed include: equivalence-checking with infinite-state systems: techniques and results;database support for multisource multiresolution scientific data;semantic annotation and indexing of news and sports videos;multimedia presentations databases;interactive indexing and retrieval of multimedia content;a model-based approach to semantic-based retrieval of visual information;Hungarian speech synthesis using a phase exact HNM approach;modelling resource transitions in constraint-based scheduling;a specification framework for real-time scheduling;string transformation for N-dimensional image compression;validation and decomposition of partially occluded images;solving conflicts of agent knowledge states in multiagent systems;specification and verification of secure business transaction systems;and the reconstruction of some 3D convex polyominoes from orthogonal projections.
We survey recent results from different areas, studying how introducing per-instance a-priori information affects the solvability and complexity of given tasks. We mainly focus on distributed, and online computation, ...
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ISBN:
(纸本)9783319042978;9783319042985
We survey recent results from different areas, studying how introducing per-instance a-priori information affects the solvability and complexity of given tasks. We mainly focus on distributed, and online computation, where some sort of hidden information plays a crucial role: in the distributed computing, typically nodes have no or only limited information about the global state of the network;in online problems, the algorithm lacks the information about the future input. the traditional approach in both areas is to study how the properties of the problem change if some partial information is available (e. g., nodes of a distributed system have sense of direction, the online algorithm has the promise that the input requests come in some specified order etc.). Recently, attempts have been made to study this information from a quantitative point of view: there is an oracle that delivers (per-instance) best-case information of a limited size, and the relationship between the amount of the additional information, and the benefit it can provide to the algorithm, is investigated. We show cases where this relationship has a form of a trade-off, and others where one or more thresholds can be identified.
ECN is a powerful tool that can achieve low latency and high throughput simultaneously. Support ECN for multi-queue scenarios is an industry trend in datacenter networks. However, ECN schemes developed for per-port ma...
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ISBN:
(纸本)9781538668719
ECN is a powerful tool that can achieve low latency and high throughput simultaneously. Support ECN for multi-queue scenarios is an industry trend in datacenter networks. However, ECN schemes developed for per-port marking cannot be applied directly to the multi-queue scenarios. It hurts at least one metric among latency, throughput, and the scheduling policy. State-of-the-art multi-queue ECN marking schemes each has its own limitations. In this paper, we present per-Port Marking with Selective Blindness (PMSB). the intuition is that: if a flow is found to be a victim of per-port marking, we can either revoke the marking or cancel the flow back-off even if its packets qualify the per-port threshold (i.e., selective blindness). By breaking the fixed causal relationship between ECN marking and flow back-off, flows from un-congested queues can be protected. We evaluate PMSB with large-scale NS-3 simulations. Our results demonstrate that PMSB can preserve a given scheduling policy. Compared withthe currentpractice, PMSB can reduce the average/99% completion time for small flows by 64.49%172.89% respectively while delivering a slightly better performance for large flows.
the use of software tools has become a common practice in global software engineering to handle requirements and to exchange project status amongst distributed teams and stakeholders. In context of agile software deve...
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In John Tantalo's on-line game Planarity the player is given a non-plane straight-line drawing of a planar graph. the aim is to make the drawing plane as quickly as possible by moving vertices. Pach and Tardos hav...
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ISBN:
(数字)9783540775669
ISBN:
(纸本)9783540775652
In John Tantalo's on-line game Planarity the player is given a non-plane straight-line drawing of a planar graph. the aim is to make the drawing plane as quickly as possible by moving vertices. Pach and Tardos have posed a related problem: can any straight-line drawing of any planar graph with n vertices be made plane by vertex moves while keeping Omega(n(epsilon)) vertices fixed for some absolute constant epsilon > 0? It is known that three vertices can always be kept (if n > 5). We still do not solve the problem of Pach and Tardos, but we report some progress. We prove that the number of vertices that can be kept actually grows withthe size of the graph. More specifically, we give a lower bound of Omega(root log n/ log log n) on this number. By the same technique we show that in the case of outerplanar graphs we can keep a lot more, namely Omega(root n) vertices. We also construct a family of outerplanar graphs for which this bound is asymptotically tight.
Experimental evaluation has always been central to Information Retrieval research. the field is increasingly moving towards online evaluation, which involves experimenting with real, unsuspecting users in their natura...
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Information systems have to work correctly and securely as expected (dependability);have to be able to communicate and understand each other's data (interoperability);and have to be able to change in an evolutiona...
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Information systems have to work correctly and securely as expected (dependability);have to be able to communicate and understand each other's data (interoperability);and have to be able to change in an evolutionary way similarly to how the organizations and their business processes are changing (evolutionary). To write software we must know the requirements;to prescribe the requirements we have to understand the domain;to understand the domain we have to analyze and model one. the domain or application domain (e.g. banking, healthcare, clinical laboratory and etc.) can be anything to which computing can be applied. In analyzing and modeling domains we use archetypes and archetype patterns as meta-models. We explain what the archetypes and archetype patterns are and how we utilize them in the development of domain models, requirements, and software in order to meet the dependability, interoperability and evolutionary criteria. Crown Copyright (C) 2014 Published by Elsevier B. V. this is an open access article under the CC BY-NC-ND license.
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