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.
Highly reliable and effective failure detection and isolation (FDI) software is crucial in modern avionics systems.that tolerate hardware failures in real time. The FDI function is an excellent opportunity for applyin...
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ISBN:
(纸本)0818608757
Highly reliable and effective failure detection and isolation (FDI) software is crucial in modern avionics systems.that tolerate hardware failures in real time. The FDI function is an excellent opportunity for applying the principal of software design diversity to the fullest, i.e., algorithm diversity, in order to provide gains in functional performance as well as potentially enhancing the reliability of the software. The authors examine algorithm diversity applied to the redundancy management software for a hardware fault-tolerant sensor array. Results of an experiment are presented that show the performance gains that can be provided by utilizing the consensus of three diverse algorithms for sensor FDI.
software code reuse has long been touted as a reliable and efficient software development paradigm. Whilst this practice has numerous benefits, it is inherently susceptible to latent vulnerabilities. Source code which...
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ISBN:
(纸本)9780769542508
software code reuse has long been touted as a reliable and efficient software development paradigm. Whilst this practice has numerous benefits, it is inherently susceptible to latent vulnerabilities. Source code which is re-used without being patched for various reasons may result in vulnerable binaries, despite the vulnerabilities being made publicly known. To aggravate matters, crackers have access to information on these vulnerabilities as well. Defenders need to ensure all loopholes are patched, while attackers need just one such loophole. In this work, we define latent vulnerabilities, and study the prevalence of the problem. This provides us the motivation, and an insight into the future work to be done in solving the problem. Our results show that unpatched source files which are more than one year old are commonly used in the latest operating systems. In fact, several of these files are more than ten years old. We explore the premises of using symbols in identifying binaries and conclude that they are insufficient in solving the problem. Additionally, we discuss two possible approaches to solve the problem.
A recursive algorithm for computing a lower bound on the all-terminal reliability of an n-dimensional hypercube is presented. The recursive step decomposes an n-dimensional hypercube into lower dimension hypercubes th...
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A recursive algorithm for computing a lower bound on the all-terminal reliability of an n-dimensional hypercube is presented. The recursive step decomposes an n-dimensional hypercube into lower dimension hypercubes that are linked together. As an illustration of the effectiveness and power of this method, a lower bound is computed on the all-terminal reliability of the 16-dimensional hypercube (Connection Machine architecture) whose links number 219. The notation and assumptions are defined, and background information on bounding the reliability polynomial is provided. Methods for tightening these bounds for the analysis of the hypercube architecture are discussed.
The following topics are dealt with: distributed operating systems.local area networks;network fault tolerance;hypercubes;distributeddatabases;real-time systems.replicated programs;computer architectures;and voting. ...
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The following topics are dealt with: distributed operating systems.local area networks;network fault tolerance;hypercubes;distributeddatabases;real-time systems.replicated programs;computer architectures;and voting. Abstracts of individual papers can be found under the relevant classification codes in this or other issues.
The Peer-To-Peer (P2P) paradigm is a promising approach for several distributed applications, among which distributed storage systems. SPINA is a software architecture that aims at encompassing indexing and retrieval ...
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The Peer-To-Peer (P2P) paradigm is a promising approach for several distributed applications, among which distributed storage systems. SPINA is a software architecture that aims at encompassing indexing and retrieval of unstructured documents stored in a P2P network. This paper describes the current status of the design and the implementation of this software architecture.
Focus is on recovery of transactions in a distributed DB/DC system. The objective is to use transaction-level structural information to eliminate costly lower-level handshaking protocols, eliminate the need for any ce...
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ISBN:
(纸本)0818606908
Focus is on recovery of transactions in a distributed DB/DC system. The objective is to use transaction-level structural information to eliminate costly lower-level handshaking protocols, eliminate the need for any centralized recovery management mechanism by making recovery actions local to interacting components, and eliminate propagation of recovery actions to more than one antecedent or precedent component. Progressive recovery is a way of tracking the progress of a transaction to meet the above objective. Transaction processing involves different execution stages (DC, DB, followed by the DC), perhaps on different processors. Some stages make database changes and others are purely transformations of messages. The latter permit re-executions without side effects. The former must be well protected from re-executions. In contrast with optimistic recovery schemes, progressive recovery does not track communication and state dependencies.
Coordinated Atomic Actions (CAAs) have been introduced about ten years ago as a conceptual framework for developing fault-tolerant concurrent systems. All the work done since then extended the CAA framework with the c...
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ISBN:
(纸本)9780769530246
Coordinated Atomic Actions (CAAs) have been introduced about ten years ago as a conceptual framework for developing fault-tolerant concurrent systems. All the work done since then extended the CAA framework with the capabilities to model, verify, and implement concurrent distributedsystems.following pre-defined development methodologies. As a result, CAAs, compared to other approaches available, offer a rich set of means for engineering dependable systems. Nevertheless, it is sometimes difficult to have a global and analytical view of all the features available as this concept provides a number of features which need to be applied in combination. The main contribution of this paper is in presenting a complete state-of-the-art overview of the work done around CAAs from the three perspectives: the definitions of the fundamental concepts, their various semantics and the means supporting formal verification. This paper is useful for the potential CAAs users in helping them to avoid misinterpretation when employing all the available features. Finally, our paper should contribute in better understanding of the likely directions in which the CAA framework may evolve in the near future.
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.
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