16966197
Integrated system interoperability testing with applications to VoIP
This work has been motivated by the need to test interoperability of systems carrying voice calls over the IP network. The voice over IP (VoIP) systems must be integrated and interoperate with the existing public switched telephone network (PSTN) before they are widely adopted. Standards have been developed to address this problem, but unfortunately different standards bodies and commercial consortiums have defined different standards. Furthermore, the prevailing VoIP standard such as H.323 is incomplete, complex, and presents the implementers with "vendors latitudes". As a result, there is no guarantee that the integrated VoIP systems would interoperate properly even if the implementations are all H.323-compliant. Thus interoperability testing has become indispensable. We want to test all the system interoperations by exercising all the required patterns of "interoperating behaviors". On the other hand, test execution in real environment is expensive, and we want to minimize the number of tests while maintaining the coverage. We present a general method for automatic generation of test cases, which cover all the required system interoperations and contain a minimal number of tests. We study data structures and efficient test generation algorithms, which take time proportional to the total test case size. Finally, we report experimental results on VoIP systems.
11856887
Approximation of linear functionals on a banach space with a Gaussian measure
Abstract We study approximation of linear functionals on separable Banach spaces equipped with a Gaussian measure. We study optimal information and optimal algorithms in average case, probabilistic, and asymptotic settings, for a general error criterion. We prove that adaptive information is not more powerful than nonadaptive information and that μ-spline algorithms, which are linear, are optimal in all three settings. Some of these results hold for approximation of linear operators. We specialize our results to the space of functions with continuous r th derivatives, equipped with a Wiener measure. In particular, we show that the natural splines of degree 2 r + I yield the optimal algorithms. We apply the general results to the problem of integration.
206832588
Optimization problems from feature testing of communication protocols
In feature testing of communication protocols, we want to construct a minimal number of tests with a desirable fault coverage. We model the protocols by extended finite state machines and reduce the test generation process to optimization problems on graphs. We study efficient algorithms and their complexity. We report experimental results on real systems, including Personal HandyPhone System, a 5ESS based ISDN wireless system, and 5ESS Intelligent Network Application Protocol.
38528864
Coping With Discontinuities In Computer Vision: Their Detection, Classification, And Measurement
45853491
Testing Finite-State Machines: State Identification and Verification
We study the complexity of two fundamental problems in the testing of finite-state machines. 1) Distinguishing sequences (state identification). We show that it is PSPACE-complete to determine whether a finite-state machine has a preset distinguishing sequence. There are machines that have distinguishing sequences, but only of exponential length. We give a polynomial time algorithm that determines whether a finite-state machine has an adaptive distinguishing sequence. (The previous classical algorithms take exponential time.) Furthermore, if there is an adaptive distinguishing sequence, then we give an efficient algorithm that constructs such a sequence of length at most n(n/spl minus/1)/2 (which is the best possible), where n is the number of states. 2) Unique input output sequences (state verification). It is PSPACE-complete to determine whether a state of a machine has a unique input output sequence. There are machines whose states have unique input output sequences but only of exponential length. >
206418940
Residual Analysis for Feature Detection
It is shown that in a very simple form residual analysis achieves results that are at least as good as if not better than those obtained by other techniques. There are many ways for extensions of the method. For example, moving average filters of regularization can be used to obtain the residual images. Also, the strength of the correlation, measured by D/sub rr/(O), can be used to eliminate noise, weak edges, etc. A more ambitious extension is by considering smoothing filters that leave invariant the function representing the reflectance from smooth surfaces. >
13592174
Critical area computation—a new approach
In this paper we present a new approach for computing the critical area for shorts in a circuit layout. The critical area calculation is the main computational problem in VLSI yield prediction. The method is based on the concept of Voronoi diagrams and computes the critical area for shorts (for all possible defect radii, assuming square defects) accurately in <italic>O</italic>(<italic>n</italic> log <italic>n</italic>) time, where <italic>n</italic> is the size of the input. The method is presented for rectilinear layouts but it is extendible to general layouts. As a byproduct we briefly sketch how to speed up the grid method of Wagner and Koren [16].
28781309
Automatic process-oriented control circuit generation for asynchronous high-level synthesis
As an asynchronous design style becomes popular, the request for asynchronous high-level synthesis (AHLS) tools is increasing continuously. In this paper, a method, so called process-oriented method, which generates distributed asynchronous control circuits automatically in a hierarchical and systematic manner is suggested as part of an AHLS tool. Experimental results show that the suggested method is efficient in the aspects of area and performance of derived control circuits.
1430708
Towards a mechanized metatheory of standard ML
We present an internal language with equivalent expressive power to Standard ML, and discuss its formalization in LF and the machine-checked verification of its type safety in Twelf. The internal language is intended to serve as the target of elaboration in an elaborative semantics for Standard ML in the style of Harper and Stone. Therefore, it includes all the programming mechanisms necessary to implement Standard ML, including translucent modules, abstraction, polymorphism, higher kinds, references, exceptions, recursive types, and recursive functions. Our successful formalization of the proof involved a careful interplay between the precise formulations of the various mechanisms, and required the invention of new representation and proof techniques of general interest.
2528129
Rectilinear Paths Among Rectilinear Obstacles
We address problems of finding rectilinear paths among rectilinear obstacles subject to certain optimization criteria. They have applications in the fields of motion planning and computer-aided circuit design. The criteria that we consider include minimizing the length of the path, minimizing the number of bends on the path, bounding one of the two factors (length and number of bends) and minimizing the other, and minimizing a given non-decreasing function of both the length and the number of bends. The length measure of a rectilinear path can be the total length of all the segments of the paths or just the sum of lengths of all the vertical or horizontal segments of the path. Besides the various optimization criteria for the paths that we look for, the routing environments may have different constraints. For example, the obstacles can be rectangular or rectilinear, the orientations of the path may be restricted to be horizontal or vertical on different layers in a two-layer interconnection model, or the path can penetrate the obstacles and pay extra costs. Previous results and problem solving approaches are summarized and compared to ours in this dissertation. 
We obtain more efficient algorithms for finding a shortest rectilinear path between two points, minimum spanning tree of a set of points, and for finding assorted paths taking both length and the number of bends into consideration. We also derive a general problem transformation scheme to convert an instance in two-layer model into an equivalent problem in one-layer model, for which previously obtained algorithms under different objective functions are applicable.
215179
Two Variations of the Minimum Steiner Problem
Given a set S of starting vertices and a set T of terminating vertices in a graph G = (V,E) with non-negative weights on edges, the minimum Steiner network problem is to find a subgraph of G with the minimum total edge weight. In such a subgraph, we require that for each vertex s$${\in}$$S and t$${\in}$$T, there is a path from s to a terminating vertex as well as a path from a starting vertex to t. This problem can easily be proven NP-hard. For solving the minimum Steiner network problem, we first present an algorithm that runs in time and space that both are polynomial in n with constant degrees, but exponential in |S|+|T|, where n is the number of vertices in G. Then we present an algorithm that uses space that is quadratic in n and runs in time that is polynomial in n with a degree O(max {max {|S|,|T|}−2,min {|S|,|T|}−1}). In spite of this degree, we prove that the number of Steiner vertices in our solution can be as large as |S|+|T|−2. Our algorithm can enumerate all possible optimal solutions. The input graph G can either be undirected or directed acyclic. We also give a linear time algorithm for the special case when min {|S|,|T|} = 1 and max {|S|,|T|} = 2.The minimum union paths problem is similar to the minimum Steiner network problem except that we are given a set H of hitting vertices in G in addition to the sets of starting and terminating vertices. We want to find a subgraph of G with the minimum total edge weight such that the conditions required by the minimum Steiner network problem are satisfied as well as the condition that every hitting vertex is on a path from a starting vertex to a terminating vertex. Furthermore, G must be directed acyclic. For solving the minimum union paths problem, we also present algorithms that have a time and space tradeoff similar to algorithms for the minimum Steiner network problem. We also give a linear time algorithm for the special case when |S| = 1, |T| = 1 and |H| = 2.