The proceedings contain 39 papers. The topics discussed include: detection of unexpected situations by applying softwarereliability growth models to test phases;resource/schedule/content model: improving testing effe...
ISBN:
(纸本)9781509019441
The proceedings contain 39 papers. The topics discussed include: detection of unexpected situations by applying softwarereliability growth models to test phases;resource/schedule/content model: improving testing effectiveness;static analysis of physical properties in Simulink models;test suites for benchmarks of static analysis tools;optimizing resiliency of distributed video surveillance system for safer city;software-defined networking (SDN) control message classification, verification, and optimization system;integrating formal methods with testing for reliability estimation of component based systems.C-SEC (Cyber SCADA evaluation capability): securing critical infrastructures;operational softwarized networks reliability management;knowledge transition: discovering workflow models from functional tests;and analyzing failure mechanism for complex software-intensive systems.
Error control codes have been widely adopted to design dependable storage systems. thus number of data accesses becomes numerous. Data access efficiency as well as energy saving are important problems. This paper prop...
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ISBN:
(纸本)9781479955848
Error control codes have been widely adopted to design dependable storage systems. thus number of data accesses becomes numerous. Data access efficiency as well as energy saving are important problems. This paper proposes a method which uses variable information word length for improving data access efficiency in dependable storage systems.
database Management systems.(DBMS) are used by software applications, to store, manipulate, and retrieve large sets of data. However, the requirements of current softwaresystems.pose various challenges to established...
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ISBN:
(纸本)9781450326278
database Management systems.(DBMS) are used by software applications, to store, manipulate, and retrieve large sets of data. However, the requirements of current softwaresystems.pose various challenges to established DBMS. First, most softwaresystems.organize their data by means of objects rather than relations leading to increased maintenance, redundancy, and transformation overhead when persisting objects to relational databases. Second, complex objects are separated into several objects resulting in Object Schizophrenia and hard to persist distributed State. Last but not least, current softwaresystems.have to cope with increased complexity and changes. These challenges have lead to a general paradigm shift in the development of softwaresystems. Unfortunately, classical DBMS will become intractable, if they are not adapted to the new requirements imposed by these softwaresystems. As a result, we propose an extension of DBMS with roles to represent complex objects within a relational database and support the flexibility required by current softwaresystems. To achieve this goal, we introduces RSQL, an extension to SQL with the concept of objects playing roles when interacting with other objects. Additionally, we present a formal model for the logical representation of roles in the extended DBMS.
Very large scale distributedsystems.provide some of the most interesting research challenges while at the same time being increasingly required by nowadays applications. The escalation in the amount of connected devi...
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ISBN:
(纸本)9781479955848
Very large scale distributedsystems.provide some of the most interesting research challenges while at the same time being increasingly required by nowadays applications. The escalation in the amount of connected devices and data being produced and exchanged, demands new data management systems. Although new data stores are continuously being proposed, they are not suitable for very large scale environments. The high levels of churn and constant dynamics found in very large scale systems.demand robust, proactive and unstructured approaches to data management. In this paper we propose a novel data store solely based on epidemic (or gossip-based) protocols. It leverages the capacity of these protocols to provide data persistence guarantees even in highly dynamic, massive scale systems. We provide an open source prototype of the data store and correspondent evaluation.
Testing data-intensive systems.is paramount to increase our reliance on information processed in e-governance, scientific/medical research, and social networks. A common practice in the industrial testing process is t...
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ISBN:
(纸本)9781479960323
Testing data-intensive systems.is paramount to increase our reliance on information processed in e-governance, scientific/medical research, and social networks. A common practice in the industrial testing process is to use test databases copied from live production streams to test functionality of complex database applications that manage well-formedness of data and its adherence to business rules in these systems. This practice is often based on the assumption that the test database adequately covers realistic scenarios to test, hopefully, all functionality in these applications. There is a need to systematically evaluate this assumption. We present a tool-supported method to model realistic scenarios and verify whether copied test databases actually cover them and consequently facilitate adequate testing. We conceptualize realistic scenarios as data interactions between fields cross-cutting a complex database schema and model them as test cases in a classification tree model. We present a human-in-the-loop tool, DEPICT, that uses the classification tree model as input to (a) facilitate interactive selection of a connected subgraph from often many possible paths of interactions between tables specified in the model (b) automatically generate SQL queries to create an inner join between tables in the connected subgraph (c) extract records from the join and generate a visual report of satisfied and unsatisfied interactions hence quantifying test adequacy of the test database. We report our experience as a qualitative evaluation of approach and with a large industrial database from the Norwegian Customs and Excise information system TVINN featuring large and complex databases with millions of records.
softwaresystems.running continuously for a long time often confront software aging, which is the phenomenon of progressive degradation of execution environment caused by latent software faults. Removal of such faults...
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ISBN:
(纸本)9781479955848
softwaresystems.running continuously for a long time often confront software aging, which is the phenomenon of progressive degradation of execution environment caused by latent software faults. Removal of such faults in software development process is a crucial issue for system reliability. A known major obstacle is typically the large latency to discover the existence of software aging. We propose a systematic approach to detect software aging which has shorter test time and higher accuracy compared to traditional aging detection via stress testing and trend detection. The approach is based on a differential analysis where a software version under test is compared against a previous version in terms of behavioral changes of resource metrics. A key instrument adopted is a divergence chart, which expresses time-dependent differences between two signals. Our experimental study focuses on memory-leak detection and evaluates divergence charts computed using multiple statistical techniques paired with application-level memory related metrics (RSS and Heap Usage). The results show that the proposed method achieves good performance for memory-leak detection in comparison to techniques widely adopted in previous works (e.g., linear regression, moving average and median).
Accountability is becoming increasingly required in today's distributedsystems. Indeed, accountability allows not only to detect faults but also to build provable evidence about the misbehaving participants of a ...
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ISBN:
(纸本)9781479955848
Accountability is becoming increasingly required in today's distributedsystems. Indeed, accountability allows not only to detect faults but also to build provable evidence about the misbehaving participants of a distributed system. There exists a number of solutions to enforce accountability in distributedsystems. among which PeerReview is the only solution that is not specific to a given application and that does not rely on any special hardware. However, this protocol is not resilient to selfish nodes, i.e. nodes that aim at maximising their benefit without contributing their fair share to the system. Our objective in this paper is to provide a software solution to enforce accountability on any underlying application in presence of selfish nodes. To tackle this problem, we propose the FullReview protocol. FullReview relies on game theory by embedding incentives that force nodes to stick to the protocol. We theoretically prove that our protocol is a Nash equilibrium, i.e. that nodes do not have any interest in deviating from it. Furthermore, we practically evaluate FullReview by deploying it for enforcing accountability in two applications: (1) SplitStream, an efficient multicast protocol, and (2) Onion routing, the most widely used anonymous communication protocol. Performance evaluation shows that FullReview effectively detects faults in presence of selfish nodes while incurring a small overhead compared to PeerReview and scaling as PeerReview.
In order to guarantee data reliability in distributed storage systems. erasure codes are widely used for the desirable storage properties. Nevertheless, the codes have one drawback that overmuch data are needed to rep...
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ISBN:
(纸本)9781479955848
In order to guarantee data reliability in distributed storage systems. erasure codes are widely used for the desirable storage properties. Nevertheless, the codes have one drawback that overmuch data are needed to repair a failure, resulting in both large bandwidth consuming in the network and high calculation pressure on the replacement node. For repair bandwidth problem, researchers derive the tradeoff between storage and repair traffic from network coding and propose regenerating codes. However, the constructions of regenerating codes complicate the systems.as well as recovery calculation. Hence, this paper proposes a distributed repair method based on general erasure codes to mitigate the burden of both recovery computation and network traffic. We observe that distributing recovery computation among helpers can distract the whole calculation procedure and accelerate repair speed in practical systems. Furthermore, by combining this technique with network topology, we introduce a novel repair tree to minimize repair traffic. Repair tree is also derived from network coding. The performance of the repair tree is preliminarily analyzed and evaluated, which infers that the storage-bandwidth bound of regenerating codes can be broken under this model.
Smart grids are fostering a paradigm shift in the realm of power distribution systems. Whereas traditionally different components of the power distribution system have been provided and analyzed by different teams, sm...
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ISBN:
(纸本)9781479923663
Smart grids are fostering a paradigm shift in the realm of power distribution systems. Whereas traditionally different components of the power distribution system have been provided and analyzed by different teams, smart grids require a unified and holistic approach taking into consideration the interplay of distributed generation, distribution automation topology, intelligent features, and others. In this paper, we use transient survivability metrics to create better distribution automation network designs. Our approach combines survivability analysis and power flow analysis to assess the survivability of the distribution power grid network. Additionally, we present an initial approach to automatically optimize available investment decisions with respect to survivability and investment costs. We have evaluated the feasibility of this approach by applying it to the design of a real distribution automation circuit. Our empirical results indicate that the combination of survivability analysis and power flow can provide meaningful investment. decision support for power systems.engineers.
Full-system emulation has been an extremely useful tool in developing and debugging systems.software like operating systems.and hypervisors. However, current full-system emulators lack the support for deterministic re...
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ISBN:
(纸本)9781450319225
Full-system emulation has been an extremely useful tool in developing and debugging systems.software like operating systems.and hypervisors. However, current full-system emulators lack the support for deterministic replay, which limits the reproducibility of concurrency bugs that is indispensable for analyzing and debugging the essentially multi-threaded systems.software. This paper analyzes the challenges in supporting deterministic replay in parallel full-system emulators and makes a comprehensive study on the sources of non-determinism. Unlike application-level replay systems. our system, called ReEmu, needs to log sources of non-determinism in both the guest software stack and the dynamic binary translator for faithful replay. To provide scalable and efficient record and replay on multicore machines, ReEmu makes several notable refinements to the CREW protocol that replays shared memory systems. First, being aware of the performance bottlenecks in frequent lock operations in the CREW protocol, ReEmu refines the CREW protocol with a seqlock-like design, to avoid serious contention and possible starvation in instrumentation code tracking dependence of racy accesses on a shared memory object. Second, to minimize the required log files, ReEmu only logs minimal local information regarding accesses to a shared memory location, but instead relies on an offline log processing tool to derive precise shared memory dependence for faithful replay. third, ReEmu adopts an automatic lock clustering mechanism that clusters a set of uncontended memory objects to a bulk to reduce the frequencies of lock operations, which noticeably boost performance. Our prototype ReEmu is based on our open-source COREMU system and supports scalable and efficient record and replay of full-system environments (both x64 and ARM). Performance evaluation shows that ReEmu has very good performance scalability on an Intel multicore machine. It incurs only 68.9% performance overhead on average (ranging
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