Indranil Saha | University of Pennsylvania (original) (raw)
Address: Berkeley, California, United States
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Papers by Indranil Saha
Fundamenta Informaticae, 2008
Double-tree-scan (DTS) is a new scan-path architecture that is deemed to be suitable for low-powe... more Double-tree-scan (DTS) is a new scan-path architecture that is deemed to be suitable for low-power testing of VLSI circuits. A full DTS resembles two complete k-level (k > 0) binary trees whose leaf nodes are merged pair-wise, and thus consists of exactly N k = 3 × 2 k − 2 nodes. In this paper, the problem of planar straight-line embedding of a "double-tree graph" on a rectangular grid is investigated and an O(N k ) time algorithm for drawing it, is described. The embedding requires at most 2N k grid points, with an aspect ratio lying between 1 and 3 2 . Next, techniques of embedding a partial DTS is considered when the number of nodes n = 3 × 2 k − 2, for some k. Layouts of double-tree scan-paths for some benchmark circuits are also presented to demonstrate the results.
Software implementations of controllers for physical subsystems form the core of many modern safe... more Software implementations of controllers for physical subsystems form the core of many modern safety-critical systems such as aircraft flight control and automotive engine control. A fundamental property of such implementations is stability, the guarantee that the physical plant converges to a desired behavior under the actions of the controller. We present a methodology and a tool to perform automated static analysis of embedded controller code for stability of the controlled physical system.
AbstractA key feature of control systems is robustness, the property that small perturbations in... more AbstractA key feature of control systems is robustness, the property that small perturbations in the system inputs cause only small changes in its outputs. Robustness is key to designing systems that work under uncertain or imprecise environments. While continuous control ...
Software controllers for physical processes are at the core of many safety-critical systems such ... more Software controllers for physical processes are at the core of many safety-critical systems such as avionics, automotive engine control, and process control. Despite their importance, the design and implementation of software controllers remains an art form; dependability is generally poor, and the cost of verifying systems is prohibitive. We illustrate the potential of applying program analysis tools on problems in controller design and implementation by focusing on concolic execution, a technique for systematic testing for software. In particular, we demonstrate how a concolic execution tool can be modified to automatically analyze controller implementations and (a) produce test cases achieving a coverage goal, (b) synthesize ranges for controller variables that can be used to allocate bits in a fixed-point implementation, and (c) verify robustness of an implementation under input uncertainties. We have implemented these algorithms on top of the Splat test generation tool and have carried out preliminary experiments on control software that demonstrates feasibility of the techniques.
Fundamenta Informaticae, 2008
Double-tree-scan (DTS) is a new scan-path architecture that is deemed to be suitable for low-powe... more Double-tree-scan (DTS) is a new scan-path architecture that is deemed to be suitable for low-power testing of VLSI circuits. A full DTS resembles two complete k-level (k > 0) binary trees whose leaf nodes are merged pair-wise, and thus consists of exactly N k = 3 × 2 k − 2 nodes. In this paper, the problem of planar straight-line embedding of a "double-tree graph" on a rectangular grid is investigated and an O(N k ) time algorithm for drawing it, is described. The embedding requires at most 2N k grid points, with an aspect ratio lying between 1 and 3 2 . Next, techniques of embedding a partial DTS is considered when the number of nodes n = 3 × 2 k − 2, for some k. Layouts of double-tree scan-paths for some benchmark circuits are also presented to demonstrate the results.
Software implementations of controllers for physical subsystems form the core of many modern safe... more Software implementations of controllers for physical subsystems form the core of many modern safety-critical systems such as aircraft flight control and automotive engine control. A fundamental property of such implementations is stability, the guarantee that the physical plant converges to a desired behavior under the actions of the controller. We present a methodology and a tool to perform automated static analysis of embedded controller code for stability of the controlled physical system.
AbstractA key feature of control systems is robustness, the property that small perturbations in... more AbstractA key feature of control systems is robustness, the property that small perturbations in the system inputs cause only small changes in its outputs. Robustness is key to designing systems that work under uncertain or imprecise environments. While continuous control ...
Software controllers for physical processes are at the core of many safety-critical systems such ... more Software controllers for physical processes are at the core of many safety-critical systems such as avionics, automotive engine control, and process control. Despite their importance, the design and implementation of software controllers remains an art form; dependability is generally poor, and the cost of verifying systems is prohibitive. We illustrate the potential of applying program analysis tools on problems in controller design and implementation by focusing on concolic execution, a technique for systematic testing for software. In particular, we demonstrate how a concolic execution tool can be modified to automatically analyze controller implementations and (a) produce test cases achieving a coverage goal, (b) synthesize ranges for controller variables that can be used to allocate bits in a fixed-point implementation, and (c) verify robustness of an implementation under input uncertainties. We have implemented these algorithms on top of the Splat test generation tool and have carried out preliminary experiments on control software that demonstrates feasibility of the techniques.