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Saurabh Srivastava

Bio: Saurabh Srivastava is an academic researcher from Indian Institutes of Technology. The author has contributed to research in topics: Program synthesis & Predicate abstraction. The author has an hindex of 15, co-authored 52 publications receiving 1258 citations. Previous affiliations of Saurabh Srivastava include University of California, Berkeley & Microsoft.


Papers
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Journal ArticleDOI
04 Jun 2011
TL;DR: The problem of semi-automated inversion of imperative programs, which has the potential to make it much easier and less error prone to write programs that naturally pair as inverses, is investigated and a novel synthesis technique called Path-based inductive synthesis (PINS) is proposed.
Abstract: In this paper, we investigate the problem of semi-automated inversion of imperative programs, which has the potential to make it much easier and less error prone to write programs that naturally pair as inverses, such as insert/delete operations, compressors/decompressors, and so on. Viewing inversion as a subproblem of program synthesis, we propose a novel synthesis technique called Path-based inductive synthesis (PINS) and apply it to inversion. PINS starts from a program P and a template T for its inverse. PINS then iteratively refines the space of template instantiations by exploring paths in the composition of P and T with symbolic execution. PINS uses an SMT solver to intelligently guide the refinement process, based on the paths explored so far. The key idea motivating this approach is the small path-bound hypothesis: that the behavior of a program can be summarized with a small, carefully chosen set of its program paths.We evaluated PINS by using it to invert 14 programs such as compressors (e.g., Lempel-Ziv-Welch), encoders (e.g., UUEncode), and arithmetic operations (e.g., vector rotation). Most of these examples are difficult or impossible to invert using prior techniques, but PINS was able to invert all of them. We also found that a semi-automated technique we developed to mine a template from the program to be inverted worked well. In our experiments, PINS takes between one second to thirty minutes to synthesize inverses. We believe this proof-of-concept implementation demonstrates the viability of the PINS approach to program synthesis.

68 citations

Book ChapterDOI
16 Dec 2008
TL;DR: The key idea of the technique is to represent each invariant in bounded DNF form by means of boolean indicator variables, one for each predicate p and each disjunct d denoting whether p is present in d or not.
Abstract: This paper describes a constraint-based invariant generation technique for proving the validity of safety assertions over the domain of predicate abstraction in an interprocedural setting. The key idea of the technique is to represent each invariant in bounded DNF form by means of boolean indicator variables, one for each predicate p and each disjunct d denoting whether p is present in d or not. The verification condition of the program is then encoded by means of a boolean formula over these boolean indicator variables such that any satisfying assignment to the formula yields the inductive invariants for proving the validity of given program assertions. This paper also describes how to use the constraint-based methodology for generating maximally-weak preconditions for safety assertions. An interesting application of maximally-weak precondition generation is to produce maximally-general counterexamples for safety assertions. We also present preliminary experimental evidence demonstrating the feasibility of this technique.

62 citations

Proceedings ArticleDOI
23 Jan 2013
TL;DR: This paper shows how to automatically synthesize a concurrent in-silico model for cell development given in-vivo experiments of how particular mutations influence the experiment outcome, and develops algorithms for detecting ambiguity in specifications and removing redundancy from specifications.
Abstract: Executable biology presents new challenges to formal methods. This paper addresses two problems that cell biologists face when developing formally analyzable models.First, we show how to automatically synthesize a concurrent in-silico model for cell development given in-vivo experiments of how particular mutations influence the experiment outcome. The problem of synthesis under mutations is unique because mutations may produce non-deterministic outcomes (presumably by introducing races between competing signaling pathways in the cells) and the synthesized model must be able to replay all these outcomes in order to faithfully describe the modeled cellular processes. In contrast, a "regular" concurrent program is correct if it picks any outcome allowed by the non-deterministic specification. We developed synthesis algorithms and synthesized a model of cell fate determination of the earthworm C. elegans. A version of this model previously took systems biologists months to develop.Second, we address the problem of under-constrained specifications that arise due to incomplete sets of mutation experiments. Under-constrained specifications give rise to distinct models, each explaining the same phenomenon differently. Addressing the ambiguity of specifications corresponds to analyzing the space of plausible models. We develop algorithms for detecting ambiguity in specifications, i.e., whether there exist alternative models that would produce different fates on some unperformed experiment, and for removing redundancy from specifications, i.e., computing minimal non-ambiguous specifications.Additionally, we develop a modeling language and embed it into Scala. We describe how this language design and embedding allows us to build an efficient synthesizer. For our C. elegans case study, we infer two observationally equivalent models expressing different biological hypotheses through different protein interactions. One of these hypotheses was previously unknown to biologists.

47 citations

Journal ArticleDOI
TL;DR: Hand dorsal images acquired under infrared light are used to design an accurate personal authentication system and exhibits better performance than state of the art systems and unimodal systems.
Abstract: An acquisition system is designed to simultaneously acquire palm dorsal vein and infrared (IR) hand geometry.A novel quality parameter is proposed for palm dorsal vein.A quality based variational approach is proposed for vein extraction that can handle hair, skin texture and variable width veins.Several IR hand features are extracted accurately even in absence of texture and consolidated.The proposed system exhibits better performance than state of the art systems and unimodal systems. Display Omitted In this paper, hand dorsal images acquired under infrared light are used to design an accurate personal authentication system. Each of the image is segmented into palm dorsal and fingers which are subsequently used to extract palm dorsal veins and infrared hand geometry features respectively. A new quality estimation algorithm is proposed to estimate the quality of palm dorsal which assigns low values to the pixels containing hair or skin texture. Palm dorsal is enhanced using filtering. For vein extraction, information provided by the enhanced image and the vein quality is consolidated using a variational approach. The proposed vein extraction can handle the issues of hair, skin texture and variable width veins so as to extract the genuine veins accurately. Several post processing techniques are introduced in this paper for accurate feature extraction of infrared hand geometry features. Matching scores are obtained by matching palm dorsal veins and infrared hand geometry features. These are eventually fused for authentication. For performance evaluation, a database of 1500 hand images acquired from 300 different hands is created. Experimental results demonstrate the superiority of the proposed system over existing systems.

47 citations

Proceedings ArticleDOI
28 Sep 2002
TL;DR: This paper proposes a novel method of constructing the clusters and a backbone based on the concept of a k-tree core and proposes an hierarchical routing scheme using this cluster information and evaluates its performance through extensive simulations.
Abstract: The problem of routing in Mobile Ad hoc Networks is non-trivial because of the dynamic nature of the network topology. In addition to computing shortest paths, as in wire-line networks, any routing scheme must consider that the topology of the network can vary while the packet is being routed.Cluster based schemes have been proposed which segregate the network into manageable sets for maintaining routing information. In this paper we propose a novel method of constructing the clusters and a backbone based on the concept of a k-tree core. We also propose an hierarchical routing scheme using this cluster information and evaluate its performance through extensive simulations.

36 citations


Cited by
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01 Jan 1978
TL;DR: This ebook is the first authorized digital version of Kernighan and Ritchie's 1988 classic, The C Programming Language (2nd Ed.), and is a "must-have" reference for every serious programmer's digital library.
Abstract: This ebook is the first authorized digital version of Kernighan and Ritchie's 1988 classic, The C Programming Language (2nd Ed.). One of the best-selling programming books published in the last fifty years, "K&R" has been called everything from the "bible" to "a landmark in computer science" and it has influenced generations of programmers. Available now for all leading ebook platforms, this concise and beautifully written text is a "must-have" reference for every serious programmers digital library. As modestly described by the authors in the Preface to the First Edition, this "is not an introductory programming manual; it assumes some familiarity with basic programming concepts like variables, assignment statements, loops, and functions. Nonetheless, a novice programmer should be able to read along and pick up the language, although access to a more knowledgeable colleague will help."

2,120 citations

01 Jan 2009
TL;DR: This paper presents a meta-modelling framework for modeling and testing the robustness of the modeled systems and some of the techniques used in this framework have been developed and tested in the field.
Abstract: ing WS1S Systems to Verify Parameterized Networks . . . . . . . . . . . . 188 Kai Baukus, Saddek Bensalem, Yassine Lakhnech and Karsten Stahl FMona: A Tool for Expressing Validation Techniques over Infinite State Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 J.-P. Bodeveix and M. Filali Transitive Closures of Regular Relations for Verifying Infinite-State Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220 Bengt Jonsson and Marcus Nilsson Diagnostic and Test Generation Using Static Analysis to Improve Automatic Test Generation . . . . . . . . . . . . . 235 Marius Bozga, Jean-Claude Fernandez and Lucian Ghirvu Efficient Diagnostic Generation for Boolean Equation Systems . . . . . . . . . . . . 251 Radu Mateescu Efficient Model-Checking Compositional State Space Generation with Partial Order Reductions for Asynchronous Communicating Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266 Jean-Pierre Krimm and Laurent Mounier Checking for CFFD-Preorder with Tester Processes . . . . . . . . . . . . . . . . . . . . . . . 283 Juhana Helovuo and Antti Valmari Fair Bisimulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299 Thomas A. Henzinger and Sriram K. Rajamani Integrating Low Level Symmetries into Reachability Analysis . . . . . . . . . . . . . 315 Karsten Schmidt Model-Checking Tools Model Checking Support for the ASM High-Level Language . . . . . . . . . . . . . . 331 Giuseppe Del Castillo and Kirsten Winter Table of

1,687 citations

01 Jan 1997
TL;DR: In this article, the spectral ratio between horizontal and vertical components (H/V ratio) of microtremors measured at the ground surface has been used to estimate fundamental periods and amplification factors of a site, although this technique lacks theoretical background.
Abstract: The spectral ratio between horizontal and vertical components (H/V ratio) of microtremors measured at the ground surface has been used to estimate fundamental periods and amplification factors of a site, although this technique lacks theoretical background. The aim of this article is to formulate the H/V technique in terms of the characteristics of Rayleigh and Love waves, and to contribute to improve the technique. The improvement includes use of not only peaks but also troughs in the H/V ratio for reliable estimation of the period and use of a newly proposed smoothing function for better estimation of the amplification factor. The formulation leads to a simple formula for the amplification factor expressed with the H/V ratio. With microtremor data measured at 546 junior high schools in 23 wards of Tokyo, the improved technique is applied to mapping site periods and amplification factors in the area.

1,130 citations

Journal ArticleDOI
Sumit Gulwani1
26 Jan 2011
TL;DR: The design of a string programming/expression language that supports restricted forms of regular expressions, conditionals and loops is described and an algorithm based on several novel concepts for synthesizing a desired program in this language is described from input-output examples.
Abstract: We describe the design of a string programming/expression language that supports restricted forms of regular expressions, conditionals and loops. The language is expressive enough to represent a wide variety of string manipulation tasks that end-users struggle with. We describe an algorithm based on several novel concepts for synthesizing a desired program in this language from input-output examples. The synthesis algorithm is very efficient taking a fraction of a second for various benchmark examples. The synthesis algorithm is interactive and has several desirable features: it can rank multiple solutions and has fast convergence, it can detect noise in the user input, and it supports an active interaction model wherein the user is prompted to provide outputs on inputs that may have multiple computational interpretations.The algorithm has been implemented as an interactive add-in for Microsoft Excel spreadsheet system. The prototype tool has met the golden test - it has synthesized part of itself, and has been used to solve problems beyond author's imagination.

801 citations

Journal ArticleDOI
TL;DR: A literature review article provides a comprehensive overview of literature related to a theme/theory/method and synthesizes prior studies to strengthen the foundation of knowledge as mentioned in this paper. But, there are not many reviews published describing how researchers can design and develop classic review articles.

660 citations