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. >
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.
6355860
Network Protocol System Fingerprinting - A Formal Approach
Network protocol system fingerprinting has been recognized as an important issue and a major threat to network security. Prevalent works rely largely on human experiences and insight of the protocol system specifications and implementations. Such ad-hoc approaches are inadequate in dealing with large complex protocol systems. In this paper we propose a formal approach for automated protocol system fingerprinting analysis and experiment. Parameterized Extended Finite State Machine is used to model protocol systems, and four categories of fingerprinting problems are formally defined. We propose and analyze algorithms for both active and passive fingerprinting and present our experimental results on Internet protocols. Furthermore, we investigate protection techniques against malicious fingerprinting and discuss the feasibility of two defense schemes, based on the protocol and application scenarios.
12288623
Discontinuity detection from band-limited signals
Abstract The problem of detection, classification, and measurement of discontinuities arises in many applications in science and technology. It is complex because of the noise corrupting the data. It is difficult to distinguish the discontinuities of the underlying structure from the false discontinuities from the noise. Furthermore, in applications such as edge detection from intensity images, due to the effects of the point spread function of the optic system, the discontinuities of the intensity surface of the underlying scene are not well represented in the intensity image, which is band-limited. This introduces additional complication into the discontinuity detection process. We study discontinuity detection from band-limited signals. We propose a discontinuity detector, which consists of a pair of a pattern and a linear filter. We show that for a discontinuity in the signal there is a scaled pattern in the filter response. The location of the pattern is the location of the discontinuity, and the scaling factor of the pattern is the size of the discontinuity. We derive a necessary and sufficient condition for the one-to-one correspondence between the discontinuities of the signal and the scaled patterns in the filter response. Therefore, the problem of discontinuity detection and measurement is reduced to searching for the (scaled) pattern in the filter response. In the presence of noise, the pattern matching is approximate. We propose a statistical method for the pattern search. We study optimal detectors. We show that for white noise the optimal detectors are natural splines. Some issues related to edge detection are discussed.
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.
46374921
A Formal Specification of the ATM ABR Rate Control Scheme
Abstract Formal specifications are indispensable for computer-aided validation, verification, and testing of communication protocols. However, a large number of practical protocols, including those for ATM, have only informal English specifications. A formal specification helps in achieving a consistent interpretation and thus increases the likelihood of interoperable implementations. As a case study, we consider an important protocol — ATM's Available Bit Rate (ABR) service specification. The ABR source/destination policies have been specified using an English description in the main body of the ATM Forum's draft Traffic Management specification, from which it is hard to conduct a formal analysis. It must be noted however that considerable energy has been spent in providing a reasonably precise specification, while allowing for appropriate implementation latitude. However, an English description still has the potential for different interpretations, which may lead to discrepancy in different vendors' implementations and cause serious problems in interoperability of the communication entities made by different manufacturers. We model the ABR protocols by parameterized communicating extended finite state machines with timers, which is often called a transition system. The protocol is formally specified by the specification of the transitions of the system. We also provide insights gained in the derivation of the formal specification. Furthermore, we introduce a scheduler, involved in transmitting queued cells at the allowed cell rate to meet the minimal requirements from the source/destination protocols. We present the transitions for the source/destination/scheduler machines primarily for transmitting in-rate cells.
12480757
Robotic sensing for the partially sighted
Partial sightedness is a sensory disability which can to some extent be alleviated by artificial aids. Many of the sensory methods used in robotics can be applied in attempts to recapture some of the sensory information a partially sighted person has lost. This paper describes a device which uses sonar and stereo vision sensors for this task. The device is portable, and is worn by the user, giving them freedom of movement over kerbs, stairs and rough ground. Sensor motion during walking is measured using visual egomotion recovery and odometry, and has been modelled to allow compensation in the sensor readings. A ground position estimate is continually updated by scene ground-plane fitting, or from the walk-motion model, and is used to classify scene features as obstacles or parts of the ground. Methods for the robust reconstruction of image points and lines into scene features are developed. The recognition of world objects of exceptional significance to a mobile person - kerbs and stairs - is given particular attention. A user interface, which has undergone limited real world testing, is also described. Experimental results are presented for the various parts of the system.
27113053
A Multimedia Office Filing System
445935
The TIGR rice genome annotation resource: annotating the rice genome and creating resources for plant biologists
Rice is not only a major food staple for the world's population but it also is a model species for a major group of flowering plants, the monocotyledonous plants. Draft genomic sequence of two subspecies of rice, Oryza sativa spp. japonica and indica ssp. are publicly available. To provide the community with a resource to data-mine the rice genome, we have constructed an annotation resource for rice (http://www.tigr.org/tdb/e2k1/osa1/). In this resource, we have annotated the rice genome for gene content, identified motifs/domains within the predicted genes, constructed a rice repeat database, identified related sequences in other plant species, and identified syntenic sequences between rice and maize. All of the data is available through web-based interfaces, FTP downloads, and a Distributed Annotation System.
2458216
Non-uniform Segmentation for Hardware Function Evaluation
This paper presents a method for evaluating functions in hardware based on polynomial approximation with non-uniform segments. The novel use of non-uniform segments enables us to approximate non-linear regions of a function particularly well. The appropriate segment address for a given function can be rapidly calculated in run time by a simple combinational circuit. Scaling factors are used to deal with large polynomial coefficients and to trade precision with range. Our function evaluator is based on first-order polynomials, and is suitable for applications requiring high performance with small area, at the expense of accuracy. The proposed method is illustrated using two functions, \(\sqrt{-\ln(x)}\) and cos(2 πx), which have been used in Gaussian noise generation.
17000976
A Faster One-Dimensional Topological Compaction Algorithm
We consider the problem of one-dimensional topological compaction with jog insertions. Combining both geometric and graph theoretic approaches we present a faster and simpler algorithm, improving over previous results. The compaction algorithm takes as input a sketch consisting of a set F of features and a set W of wires, and minimizes the horizontal width of the sketch while maintaining its routability. The algorithm consists of the following steps: constructing a horizontal constraint graph, computing all possible jog positions, computing the critical path, relocating the features and reconstructing a new sketch homotopic to the input sketch suitable for detailed routing. The algorithm runs in O(|F| · |W|) worst-case time and space, which is asymptotically optimal in the worst case. Experimental results are also presented.