Shankar, A. UdayaOverview
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Most widely held works by
A. Udaya Shankar
Distributed programming theory and practice
by A. Udaya Shankar
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9 editions published between 2012 and 2013 in English and held by 341 WorldCat member libraries worldwide Distributed Programming: Theory and Practice presents a practical and rigorous method to develop distributed programs that correctly implement their specifications. The method also covers how to write specifications and how to use them. Numerous examples such as bounded buffers, distributed locks, messagepassing services, and distributed termination detection illustrate the method. Larger examples include data transfer protocols, distributed shared memory, and TCP network sockets. Distributed Programming: Theory and Practice bridges the gap between books that focus on specific concurrent programming languages and books that focus on distributed algorithms. Programs are written in a "reallife" programming notation, along the lines of Java and Python with explicit instantiation of threads and programs. Students and programmers will see these as programs and not "merely" algorithms in pseudocode. The programs implement interesting algorithms and solve problems that are large enough to serve as projects in programming classes and software engineering classes. Exercises and examples are included at the end of each chapter with online access to the solutions. Distributed Programming: Theory and Practice is designed as an advancedlevel text book for students in computer science and electrical engineering. Programmers, software engineers and researchers working in this field will also find this book useful
A stepwise refinement heuristic for protocol construction
by A. Udaya Shankar
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Book
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5 editions published between 1987 and 1990 in English and held by 10 WorldCat member libraries worldwide Abstract: "We present a stepwise refinement heuristic to construct distributed systems. The heuristic is based upon a conditional refinement relation between system specifications, and a 'Marking'. It is applied to construct four sliding window protocols that provide reliable data transfer over unreliable communication channels. The protocols use moduloN sequence numbers. The first protocol is for channels that can only lose messages in transit. By refining this protocol, we obtain three protocols for channels that can lose, reorder and duplicate messages in transit. The protocols herein are less restrictive and easier to implement than sliding window protocols previously studied in the protocol verification literature."
Hierarchical interdomain routing protocol with ondemand ToS and policy resolution
by Cengiz Alaettinoğlu
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Book
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2 editions published between 1993 and 1994 in English and held by 8 WorldCat member libraries worldwide Abstract: "Traditional interdomain routing protocols based on superdomains maintain either 'strong' or 'weak' ToS and policy constraints for each visible superdomain. With strong constraints, a valid path may not be found even though one exits; with weak constraints, an invalid domainlevel path may be treated as a valid path. We present an inter domain routing protocol based on superdomains, which always finds a valid path if one exists. Both strong and weak constraints are maintained for each visible superdomain. If the strong constraints of superdomains are satisfied, then the path is valid. If the weak constraints of a superdomain are satisfied but the strong constraints are not, the source uses a query protocol to obtain a more detailed 'internal' view of the superdomain, and searches again for a valid path
An introduction to assertional reasoning for concurrent systems
by A. Udaya Shankar
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Book
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2 editions published between 1990 and 1991 in English and held by 8 WorldCat member libraries worldwide Abstract: "This report presents a tutorial introduction to assertional reasoning for concurrent systems. A simple state transition model of concurrent systems is used. Only safety properties are considered."
Stepwise assertional design of distancevector routing algorithms
by Cengiz Alaettinoğlu
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Book
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2 editions published between 1992 and 1993 in English and held by 8 WorldCat member libraries worldwide Abstract: "There are many kinds of distancevector algorithms for adaptive routing in widearea computer networks, ranging from the classical Distributed BellmanFord to several recent algorithms that have better performance. However, these algorithms have very complicated behaviors and their analyses in the literature has been incomplete (and operational). In this paper, we present a stepwise assertional design of a recently proposed distancevector algorithm. Our design starts with the Distributed BellmanFord and goes through two intermediate algorithms. The properties established for each algorithm hold for the succeeding algorithms."
Specifying modules to satisfy interfaces : a state transition system approach
by Simon S Lam
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Book
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3 editions published between 1988 and 1991 in English and held by 7 WorldCat member libraries worldwide We then provide specifications of two modules, one based upon twophase locking and the other multiversion timestamps; the twophase locking module uses an interface offered by a physical database. We prove that each module offers the serializable interface."
A relational notation for state transition systems
by Simon S Lam
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Book
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3 editions published between 1988 and 1989 in English and held by 7 WorldCat member libraries worldwide The relational notation has two basic constructs: state formulas that represent sets of states, and event formulas that represent sets of state transitions. A relational specification consists of a state transition system, given in the relational notation, and a set of fairness assumptions. Several refinement relations between specifications are defined. To illustrate our concepts and methods, three specifications of the alternatingbit protocol are given. We also apply the theory to explain auxiliary variables. Other applications of the theory to protocol verification, composition, and conversion are discussed. Our approach is compared with the approaches of other authors
Modular design principles for protocols with an application to the transport layer
by A. Udaya Shankar
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Book
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2 editions published between 1990 and 1991 in English and held by 6 WorldCat member libraries worldwide Abstract: "A computer network consists of a hierarchy of protocols, each offering a service to the protocol above using the service offered by the protocol below. We present a method for specifying services, and for constructing the specifications of protocols that offer a given service using the service provided by the protocol below. Our method is based on assertional reasoning and a refinement relation between state transition systems. The method is demonstrated on the transport layer, which is used by application protocols such as electronic mail, file transfer, remote login, etc. We construct a succession of specifications, starting from a very abstract transport service and culminating in specific transport protocols comparable to TCP and ISO TP4
Performance comparison of routing protocols under dynamic and static file transfer connections
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Book
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1 edition published in 1992 in English and held by 5 WorldCat member libraries worldwide Abstract: "We compare the performance of two recently proposed distancevector algorithms (MerlinSegall and Extended BellmanFord) with a linkstate algorithm (SPF), under varying file transfer workload. (Unlike the traditional distancevector algorithms, these new distancevector algorithms do not suffer from longlived loops.) Our comparison is done using a recently developed network simulator, MaRS. We consider both dynamic and static file transfer connections, and both uniform and hotspot distributions of sourcesink pairs. Our conclusion is that Extended BellmanFord performs as well as SPF. This suggests that distancevector algorithms are appropriate for very large widearea networks, since their space requirements are less than that of linkstate algorithms."
Performance comparison of routing protocols using MaRS : distancevector versus linkstate
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Book
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1 edition published in 1991 in English and held by 5 WorldCat member libraries worldwide Abstract: "There are two approaches to adaptive routing protocols for widearea storeandforward networks: distancevector and linkstate. Distancevector algorithms use O(N x e) storage at each node, whereas linkstate algorithms use O(N²), where N is the number of nodes in the network and e is the average degree of a node. The ARPANET started with a distancevector algorithm (Distributed BellmanFord), but because of longlived loops, changed to a linkstate algorithm (SPF). We show, using a recently developed network simulator, MaRS, that a newly proposed distancevector algorithm (ExBF) performs as well as SPF. This suggests that distancevector algorithms are appropriate for very large widearea networks."
A simple nearoptimal solution to the drinking philosophers problem
by David Ginat
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Book
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2 editions published in 1989 in English and held by 5 WorldCat member libraries worldwide Abstract: "We provide a solution to the drinking philosophers problem, defined by Chandy and Misra [1]. Our solution, unlike theirs, does not have a dining layer. By using bounded session numbers with occasional resets, we are able to reduce the message complexity per drinking session from the order of neighbors a philosopher has to the order of bottles he needs for drinking."
A leastsquares approximation technique with an application to the transient M/M/1 queue
by JeanChrysostome Bolot
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Book
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1 edition published in 1991 in English and held by 5 WorldCat member libraries worldwide Abstract: "Many timedependent quantities in queueing systems have very complicated closedform analytic expressions but relatively simple Laplace transforms. We present an approximation technique that exploits this property. The technique is based on Parseval's theorem and integration in the complex plane using the residue theorem. It yields simple approximations that are optimal in a leastsquares sense. Furthermore, it yields analytic expressions for the leastsquares error between the approximations and the exact solutions. The technique is demonstrated on the M/M/1 queue. We obtain approximations to the transient expected queue size for arbitrary values of the traffic intensity, assuming that the queue is initially empty
A simple assertional proof system for realtime systems
by A. Udaya Shankar
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Book
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1 edition published in 1992 in English and held by 5 WorldCat member libraries worldwide Abstract: "We present a simple proof system for a realtime system model similar to that of timed I/O automata. By introducing state variables indicating the last event occurrence time and event deadline time, we can express realtime properties in terms of traditional safety and progress assertions (e.g. invariant, unless, and leadsto) which are interpreted in the standard way. As a result, we can prove them using traditional proof rules (with weak fairness assumptions being replaced by finite upper bound timing assumptions). Unlike other approaches, we do not use a 'current time' variable. The proof system is illustrated on a real time mutual exclusion algorithm. We have also applied it to examples from the timed I/O automata literature."
Typeofservice in adaptive nexthop routing
by Ibrahim Matta
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Book
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1 edition published in 1992 in English and held by 5 WorldCat member libraries worldwide Abstract: "In this paper, we propose a new approach to achieving typeofservice (TOS) with adaptive nexthop routing in widearea networks such as the Internet. We consider two traffic classes, namely delay sensitive throughputsensitive. In the traditional approach (e.g. OSPF, integrated ISIS), each node has a different nexthop for each destination and TOS, and a single FIFO queue for each outgoing link. In our approach, we attempt to isolate the two traffic classes by using two FIFO queues for each outgoing link, one for each TOS; the link is shared cyclicly between the two TOS queues. The nexthops for the delaysensitive traffic adapts to link delays of that traffic. The nexthops for the throughputsensitive traffic adapts to overall link utilizations
An assertional proof of correctness and serializability of a distributed mutual exclusion algorithm based on path reversal
by David Ginat
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Book
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2 editions published in 1988 in English and held by 5 WorldCat member libraries worldwide
On the interaction between gateway scheduling and routing
by Ibrahim Matta
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Book
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1 edition published in 1993 in English and held by 4 WorldCat member libraries worldwide Abstract: "Future computer networks are expected to provide different types of service. For this purpose, new algorithms and protocols have been proposed for gateway scheduling, flow control, and routing. The interaction between these three components is crucial to the performance of the network. Existing work has studied only the interaction between scheduling and flow control, assuming static routing. In this paper, we investigate the interaction between scheduling and adaptive routing. We view the network as a dynamical system. We apply the Liapunov direct method to derive stability conditions for the routes of different traffic classes. We show how with scheduling support for routing, the routes of the traffic classes can be isolated, thereby improving the overall network performance. Montecarlo simulation results are also presented."
Viewserver hierarchy : a scalable and adaptive interdomain routing protocol
by Cengiz Alaettinoğlu
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Book
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1 edition published in 1993 in English and held by 4 WorldCat member libraries worldwide Domainlevel views are maintained by special nodes called viewservers. Each viewserver maintains a domainlevel view of a surrounding precinct. Viewservers are organized hierarchically. To obtain domainlevel source routes, the views of one or more viewservers are merged (upto [sic] a maximum of twice the levels in the hierarchy)."
Analysis of a fluid approximation to flow control dynamics
by JeanChrysostome Bolot
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Book
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1 edition published in 1990 in English and held by 4 WorldCat member libraries worldwide Abstract: "We consider a flow control mechanism that dynamically regulates the rate of data flow into a network based on feedback information about the network state. Such mechanisms have been introduced recently in a variety of networks including the Internet, and have been advocated for future highspeed networks. We first model the flow control mechanism by a discretespace stochastic process and define appropriate performance measures for transient and steadystate regimes. However, the model does not appear to be analytically tractable and we study it through simulation. We then simplify it to a continuousspace deterministic (or fluid) model for which we can easily derive closedform solutions
Correctness proof and amortization analysis of a log n distributed mutual exclusion algorithm
by David Ginat
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Book
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1 edition published in 1988 in English and held by 4 WorldCat member libraries worldwide
Optimal leastsquares approximations to the transient behavior of the stable M/M/1 queue
by JeanChrysostome Bolot
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Book
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1 edition published in 1991 in English and held by 4 WorldCat member libraries worldwide Abstract: "We present simple exponential approximations to the transient behavior of the stable M/M/1 queue. The approximations are optimal in a leastsquares sense, and we find them to agree well with exact results. Our approach can be used to derive optimal approximations for any timedependent quantity with a known Laplace transform, e.g., the probability distribution and the moments of the queue size, of the waiting time, etc. It is the only approach we are aware of in which the error between approximations and exact results can be explicitly computed." more
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Algorithms Approximation theory Approximation theoryData processing Automatic theorem proving Computer interfaces Computer network protocols Computer programming Computer programsCorrectness Computer programsVerification Computer science Computer softwareVerification Conflict management Database management Electronic data processingDistributed processing Feedback control systems Heuristic programming Least squares Least squaresData processing Logic design Mathematical notation Packet switching (Data transmission) Parallel processing (Electronic computers) Parallel programming (Computer science) Predicate (Logic) Problem solving Problem solvingData processing Queuing theory Realtime data processing Routingmachines Software engineering TexasAustin

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