The boom of electronic commerce requires existence and use of reliable means of authentication of communicating parties. We need an analogy of hand-written signature that can be applied to electronic documents. We sha...
详细信息
The boom of electronic commerce requires existence and use of reliable means of authentication of communicating parties. We need an analogy of hand-written signature that can be applied to electronic documents. We shall call such a concept an electronic signature. There is a current trend to make electronic signatures meeting some requirements equal to hand-written signatures. This makes it a very powerful tool but, on the other hand, there are some sensitive security issues that have to be discussed and that the potential users should be aware of. In this article we would like to point out some of these issues and especially those that all electronic signature users are affected by. We have to say, it is very unwise to use a software only implementation on a non-dedicated hardware to create electronic signatures if the responsibility for such signature is not limited. Using a hardware cryptographic module that is incapable of displaying the data to be signed may still be unsatisfactory. Using a module without an independent input for authorization data does not help much, a module with an independent input is significantly better but the danger is still far from negligible. Using a dedicated system to create electronic signatures can solve many of the problems. On the other hand, it is the most expensive solution considered. We will describe a solution that is both relatively cheap and reasonably secure. We also suggest some affordable key management solutions.
We present a new scheduling algorithm Odd-Even4, which not only guarantees the hard deadlines of all periodic tasks with fewer context switches but also minimizes the average response time of bounded predictable tasks...
详细信息
In this paper we propose the Sisyphus database retrieval software performance antipattern. The antipattern occurs in application designs that process large, frequently accessed lists stored in a relational database, b...
详细信息
ISBN:
(纸本)1581135637
In this paper we propose the Sisyphus database retrieval software performance antipattern. The antipattern occurs in application designs that process large, frequently accessed lists stored in a relational database, but display only a small subset to the user. Software Performance Engineering (SPE) techniques are used to analyze the antipattern. Four solutions are evaluated: rownum and index, upper/lower bound, sequence numbering, and caching. We discuss the real world challenges of correcting this antipattern early in the application life cycle.
In many disciplines, such as social and behavioral sciences, we often have to do ordinal classification by assigning objects to ordinal classes. The fundamental objective of ordinal classification is to create an orde...
详细信息
ISBN:
(纸本)0780375084
In many disciplines, such as social and behavioral sciences, we often have to do ordinal classification by assigning objects to ordinal classes. The fundamental objective of ordinal classification is to create an ordering in the universe of discourse. As such, a decision tree for ordinal classification should aim at producing an ordering which is most consistent with the implicit ordering in the input data. Ordinal classification problems are often dealt with by treating ordinal classes as nominal classes, or by representing the classes as values on a quantitative scale. Such approaches may not lead to the most desirable results since the methods do not fit the type of data, viz. ordinal data, concerned. In this paper, we propose a new measure for assessing the quality of output from an ordinal classification approach. We also propose an induction method to generate an ordinal decision tree for ordinal classification based on this quality perspective. We demonstrate the advantage of our method using results from a set of experiments.
Fuzzy Decision Tree (FDT) induction is an extraction technique of fuzzy rules, which has been widely used in handling ambiguous classification problems related to human's thought and sense. The entire process of b...
详细信息
ISBN:
(纸本)0780375084
Fuzzy Decision Tree (FDT) induction is an extraction technique of fuzzy rules, which has been widely used in handling ambiguous classification problems related to human's thought and sense. The entire process of building FDT is based on a specified parameter (called significant level) which seriously affects the computation of fuzzy entropy and classification result of FDT. Since the value of this parameter is usually given in terms of human experience while building a FDT, it is very difficult to determine its optimal value. This paper makes an attempt to give some guidelines for how to automatically choose the optimal value of this parameter by analyzing analytic expression between this parameter and fuzzy entropy and further by investigating the decision tree's sensitivity to the parameter perturbation.
This paper presents a new document segmentation algorithm, called context-adapted wavelet-domain hidden Markov tree (CAHMT) model, which extends a recently emerged wavelet-domain hidden Markov tree (HMT) model. The pr...
详细信息
ISBN:
(纸本)0780375084
This paper presents a new document segmentation algorithm, called context-adapted wavelet-domain hidden Markov tree (CAHMT) model, which extends a recently emerged wavelet-domain hidden Markov tree (HMT) model. The proposed CAHMT can achieve more accurate quality with low computation complexity in document segmentation. In addition to further improving the segmenting performance, we combine differential operator and the lowest frequency subband with CAHMT and produce much better visually segmentation quality than the HMT does.
In this paper we propose a new scheme to extract skeleton of Ribbon-like shape with a novel wavelet function. It consists of two phases, namely: based on these perfect properties of new wavelet function, and symmetry ...
详细信息
ISBN:
(纸本)0780375084
In this paper we propose a new scheme to extract skeleton of Ribbon-like shape with a novel wavelet function. It consists of two phases, namely: based on these perfect properties of new wavelet function, and symmetry analyses of maxima moduli of wavelet transform are given. Midpoints of all pairs of contour elements are connected to generate a skeleton of the shape, which is defined as wavelet skeleton. Four basic criteria for modifying the artifacts of wavelet skeleton are presented. A corresponding algorithm is developed, and the experimental results are shown that this algorithm is capable of extracting exactly skeleton of Ribbon-like shape with different widths as well as different grey-levels.
In this paper the notion of rational fuzzy language is introduced, and a theorem is obtained: a fuzzy subset of Σ* is recognizable if and only if it′s rational. The result connects the rational fuzzy language wi...
详细信息
In this paper the notion of rational fuzzy language is introduced, and a theorem is obtained: a fuzzy subset of Σ* is recognizable if and only if it′s rational. The result connects the rational fuzzy language with fuzzy finite-state automaton language.
We give a development of universal lossy data compression based on a lossy version of the Kraft inequality. As an application, we evaluate the performance of universal mixture codebooks.
We give a development of universal lossy data compression based on a lossy version of the Kraft inequality. As an application, we evaluate the performance of universal mixture codebooks.
A stochastic method is used to optimize white all-semiconductor lamps composed of tree, four, and five primary light-emitting diodes (LEDs) with Gaussian spectra and realistic line widths typical of AlGaInP and AlGaIn...
详细信息
A stochastic method is used to optimize white all-semiconductor lamps composed of tree, four, and five primary light-emitting diodes (LEDs) with Gaussian spectra and realistic line widths typical of AlGaInP and AlGaInP LEDs. Within an optimal set of central wavelengths and relative powers, a trade-off between luminous efficacy and the general color rendering index can be performed. The quadrichromatic all-semiconductor lamp is shown to meet most needs of deluxe general lighting. However, practical implementation of this lamp requires substantial improvement of LEDs in the yellow-green region (∼570 nm).
暂无评论