WorldCat Identities

Shankar, A. Udaya

Overview
Works: 53 works in 82 publications in 1 language and 519 library holdings
Classifications: QA76.6, 005.1
Publication Timeline
Key
Publications about  A. Udaya Shankar Publications about A. Udaya Shankar
Publications by  A. Udaya Shankar Publications by A. Udaya Shankar
Most widely held works by A. Udaya Shankar
Distributed programming theory and practice by A. Udaya Shankar ( )
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, message-passing 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 "real-life" 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 pseudo-code. 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 on-line access to the solutions. Distributed Programming: Theory and Practice is designed as an advanced-level 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 ( Book )
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 modulo-N 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 inter-domain routing protocol with on-demand ToS and policy resolution by Cengiz Alaettinoğlu ( Book )
2 editions published between 1993 and 1994 in English and held by 8 WorldCat member libraries worldwide
Abstract: "Traditional inter-domain 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 domain-level 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 ( Book )
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 distance-vector routing algorithms by Cengiz Alaettinoğlu ( Book )
2 editions published between 1992 and 1993 in English and held by 8 WorldCat member libraries worldwide
Abstract: "There are many kinds of distance-vector algorithms for adaptive routing in wide-area computer networks, ranging from the classical Distributed Bellman-Ford 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 distance-vector algorithm. Our design starts with the Distributed Bellman-Ford 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 ( Book )
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 two-phase locking and the other multiversion timestamps; the two-phase 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 ( Book )
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 alternating-bit 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 ( Book )
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 ( Book )
1 edition published in 1992 in English and held by 5 WorldCat member libraries worldwide
Abstract: "We compare the performance of two recently proposed distance-vector algorithms (Merlin-Segall and Extended Bellman-Ford) with a link-state algorithm (SPF), under varying file transfer workload. (Unlike the traditional distance-vector algorithms, these new distance-vector algorithms do not suffer from long-lived 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 source-sink pairs. Our conclusion is that Extended Bellman-Ford performs as well as SPF. This suggests that distance-vector algorithms are appropriate for very large wide-area networks, since their space requirements are less than that of link-state algorithms."
Performance comparison of routing protocols using MaRS : distance-vector versus link-state ( Book )
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 wide-area store-and-forward networks: distance-vector and link-state. Distance-vector algorithms use O(N x e) storage at each node, whereas link-state 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 distance-vector algorithm (Distributed Bellman-Ford), but because of long-lived loops, changed to a link-state algorithm (SPF). We show, using a recently developed network simulator, MaRS, that a newly proposed distance-vector algorithm (ExBF) performs as well as SPF. This suggests that distance-vector algorithms are appropriate for very large wide-area networks."
A simple near-optimal solution to the drinking philosophers problem by David Ginat ( Book )
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 least-squares approximation technique with an application to the transient M/M/1 queue by Jean-Chrysostome Bolot ( Book )
1 edition published in 1991 in English and held by 5 WorldCat member libraries worldwide
Abstract: "Many time-dependent quantities in queueing systems have very complicated closed-form 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 least-squares sense. Furthermore, it yields analytic expressions for the least-squares 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 real-time systems by A. Udaya Shankar ( Book )
1 edition published in 1992 in English and held by 5 WorldCat member libraries worldwide
Abstract: "We present a simple proof system for a real-time 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 real-time properties in terms of traditional safety and progress assertions (e.g. invariant, unless, and leads-to) 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."
Type-of-service in adaptive next-hop routing by Ibrahim Matta ( Book )
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 type-of-service (TOS) with adaptive next-hop routing in wide-area networks such as the Internet. We consider two traffic classes, namely delay- sensitive throughput-sensitive. In the traditional approach (e.g. OSPF, integrated IS-IS), each node has a different next-hop 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 next-hops for the delay-sensitive traffic adapts to link delays of that traffic. The next-hops for the throughput-sensitive 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 ( Book )
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 ( Book )
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. Monte-carlo simulation results are also presented."
Viewserver hierarchy : a scalable and adaptive inter-domain routing protocol by Cengiz Alaettinoğlu ( Book )
1 edition published in 1993 in English and held by 4 WorldCat member libraries worldwide
Domain-level views are maintained by special nodes called viewservers. Each viewserver maintains a domain-level view of a surrounding precinct. Viewservers are organized hierarchically. To obtain domain-level 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 Jean-Chrysostome Bolot ( Book )
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 high-speed networks. We first model the flow control mechanism by a discrete-space stochastic process and define appropriate performance measures for transient and steady-state regimes. However, the model does not appear to be analytically tractable and we study it through simulation. We then simplify it to a continuous-space deterministic (or fluid) model for which we can easily derive closed-form solutions
Correctness proof and amortization analysis of a log n distributed mutual exclusion algorithm by David Ginat ( Book )
1 edition published in 1988 in English and held by 4 WorldCat member libraries worldwide
Optimal least-squares approximations to the transient behavior of the stable M/M/1 queue by Jean-Chrysostome Bolot ( Book )
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 least-squares sense, and we find them to agree well with exact results. Our approach can be used to derive optimal approximations for any time-dependent 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."
 
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English (42)