A Quantum Tanimoto Coefficient Fidelity for Entanglement Measurement

Fidelity plays an important role in quantum information processing, which provides a basic scale for comparing two quantum states. At present, one of the most commonly used fidelities is Uhlmann-Jozsa(U-J) fidelity. However, U-J fidelity needs to calculate the square root of the matrix, which is not trivial in the case of large or infinite density matrices. Moreover, U-J fidelity is a measure of overlap, which has limitations in some cases and cannot reflect the similarity between quantum states...     

The Relative Entropy of Entanglement of Schmidt Correlated States and Distillation

We show that a mixed state = _mna_mn|mn| can be realized by an ensemble of pure states {p_k, |_k} where . Employing this form, we discuss the relative entropy of entanglement of Schmidt correlated states. Also, we calculate the distillable entanglement of a class of mixed states. PACS: 03.67.-a; 03.65.Bz; 03.65.Ud     

基于非最大纠缠GHZ态的一种量子信息集中方案

提出了一种以非最大纠缠的四粒子GHZ态作为量子信道的概率性量子信息集中方案. 方案首先将未知的克隆态与量子信道构造系统态; 其次空间分离的三方对手中的粒子进行Bell测量, 并将测量结果通过经典通信告诉信息恢复者; 最后信息重建者做适当的测量(投影测量或者POVM 测量),将信息集中回单量子态, 从而实现量子信息集中. 进而讨论了方案的安全性和效率, 并与文献[17,23]从多角度进行了比较.     

Groverian Entanglement Measure and Evolution of Entanglement in Search Algorithm for <Emphasis Type="Italic">n</Emphasis>(= 3, 5)-Qubit Systems with Real Coefficients

Evolution of entanglement with the processing of quantum algorithms affects the outcome of the algorithm. Particularly, the performance of Grover’s search algorithm gets worsened if the initial state of the algorithm is an entangled one. The success probability of search can be seen as an operational measure of entanglement. This paper demonstrates an entanglement measure based on the performance of Grover’s search algorithm for three and five qubit systems. We also show that although the overall pattern shows growth of entanglement, its rise to a maximum and then consequent decay, the presence of local fluctuation within each iterative step is likely.      

Global asymptotic stabilisation of non-linear systems

In this article, the problem of global asymptotic stabilisation of non-linear systems is considered. First of all, the global asymptotic stability of a class of non-linear systems is considered. It is proved that the class of non-linear systems is globally asymptotically stable under certain appropriate conditions. Secondly, based on the result obtained, the global asymptotic stabilisation of a class of non-linear systems is investigated, and the feedback control laws, which globally stabilise the class of systems, are designed. Thirdly, by the coordinate change and the results obtained, the global stabilisation of the affine non-linear systems are studied, and then some sufficient conditions of stabilisation are presented. Finally, the global asymptotic stabilisation of partially linear cascade non-linear system is considered. The sufficient conditions of global stabilisation are obtained, and the corresponding feedback control laws, which stabilise the non-linear systems, are designed. In addition, some examples are given to show the effectiveness of the new results.     

A minimized automaton representation of reachable states

We consider the problem of storing a set S⊂Σ^kas a deterministic finite automaton (DFA). We show that inserting a new string σ∈Σ^k or deleting a string from the set S represented as a minimized DFA can be done in expected time O(k|Σ|), while preserving the minimality of the DFA. The method can be applied to reduce the memory requirements of model checkers that are based on explicit state enumeration. As an example, we discuss an implementation of the method for the model checker Spin.     

Effective Communication in Requirements Elicitation: A Comparison of Methodologies

The elicitation or communication of user requirements comprises an early and critical but highly error-prone stage in system development. Socially oriented methodologies provide more support for user involvement in design than the rigidity of more traditional methods, facilitating the degree of user–designer communication and the ‘capture’ of requirements. A more emergent and collaborative view of requirements elicitation and communication is required to encompass the user, contextual and organisational factors. From this accompanying literature in communication issues in requirements elicitation, a four-dimensional framework is outlined and used to appraise comparatively four different methodologies seeking to promote a closer working relationship between users and designers. The facilitation of communication between users and designers is subject to discussion of the ways in which communicative activities can be ‘optimised’ for successful requirements gathering, by making recommendations based on the four dimensions to provide fruitful considerations for system designers.     

A comparative study of the robustness of two pose estimation techniques

The paper presents an analysis of the stability of pose estimation. Stability is defined as sensitivity of the pose parameters towards noise in image features used for estimating pose. The specific emphasis of the analysis is on determining {how the stability varies with viewpoint} relative to an object and to understand the relationships between object geometry, viewpoint, and pose stability. Two pose estimation techniques are investigated. One uses a numerical scheme for finding pose parameters; the other is based on closed form solutions. Both are “pose from trihedral vertices” techniques, which provide the rotation part of object pose based on orientations of three edge segments. The analysis is based on generalized sensitivity analysis propagating the uncertainty in edge segment orientations to the resulting effect on the pose parameters. It is shown that there is a precomputable, generic relationship between viewpoint and pose stability, and that there is a drastic difference in stability over the range of viewpoints. This viewpoint variation is shared by the two investigated techniques. Additionally, the paper offers an explicit way to determine the most robust viewpoints directly for any given vertex model. Experiments on real images show that the results of the work can be used to compute the variance in pose parameters for any given pose. For the predicted {instable} viewpoints the variance in pose parameters is on the order of 20 (degrees squared), whereas the variance for robust viewpoints is on the order of 0.05 (degrees squared), i.e., two orders of magnitude difference.     

A logical view of structured files

Structured data stored in files can benefit from standard database technology. In particular, we show here how such data can be queried and updated using declarative database languages. We introduce the notion of structuring schema, which consists of a grammar annotated with database programs. Based on a structuring schema, a file can be viewed as a database structure, queried and updated as such. For queries, we show that almost standard database optimization techniques can be used to answer queries without having to construct the entire database. For updates, we study in depth the propagation to the file of an update specified on the database view of this file. The problem is not feasible in general and we present a number of negative results. The positive results consist of techniques that allow to propagate updates efficiently under some reasonable locality conditions on the structuring schemas. Received November 1, 1995 / Accepted June 20, 1997     

A Location Model for Communicating and Processing of Context

Location is one of the most important elements of context in ubiquitous computing. In this paper we describe a location model, a spatial-aware communication model and an implementation of the models that exploit location for processing and communicating context. The location model presented describes a location tree, which contains human-readable semantic and geometric information about an organisation and a structure to describe the current location of an object or a context. The proposed system is dedicated to work not only on more powerful devices like handhelds, but also on small computer systems that are embedded into everyday artefact (making them a digital artefact). Model and design decisions were made on the basis of experiences from three prototype setups with several applications, which we built from 1998 to 2002. While running these prototypes we collected experiences from designers, implementers and users and formulated them as guidelines in this paper. All the prototype applications heavily use location information for providing their functionality. We found that location is not only of use as information for the application but also important for communicating context. In this paper we introduce the concept of spatial-aware communication where data is communicated based on the relative location of digital artefacts rather than on their identity. Correspondence to: Michael Biegl, Telecooperation Office (TecO), University of Karlsruhe, Vincenz-Prieβritz-Str. 1 D-76131 Karlsruhe, Germany. Email: michael@teco.edu     

A logical approach to multilevel security of probabilistic systems

Summary. We set out a modal logic for reasoning about multilevel security of probabilistic systems. This logic contains expressions for time, probability, and knowledge. Making use of the Halpern-Tuttle framework for reasoning about knowledge and probability, we give a semantics for our logic and prove it is sound. We give two syntactic definitions of perfect multilevel security and show that their semantic interpretations are equivalent to earlier, independently motivated characterizations. We also discuss the relation between these characterizations of security and between their usefulness in security analysis.     

A Feasibility Study of Automated Natural Language Requirements Analysis in Market-Driven Development

In market-driven software development there is a strong need for support to handle congestion in the requirements engineering process, which may occur as the demand for short time-to-market is combined with a rapid arrival of new requirements from many different sources. Automated analysis of the continuous flow of incoming requirements provides an opportunity to increase the efficiency of the requirements engineering process. This paper presents empirical evaluations of the benefit of automated similarity analysis of textual requirements, where existing information retrieval techniques are used to statistically measure requirements similarity. The results show that automated analysis of similarity among textual requirements is a promising technique that may provide effective support in identifying relationships between requirements.     

A comparison of local surface geometry estimation methods

The performance of several methods for estimating local surface geometry (the principal frame plus the principal quadric) are examined by applying them to a suite of synthetic and real test data which have been corrupted by various amounts of additive Gaussian noise. Methods considered include finite differences, a facet based approach, and quadric surface fitting. The nonlinear quadric fitting method considered was found to perform the best but has the greatest computational cost. The facet based approach works as well as the other quadric fitting methods and has a much smaller computational cost. Hence it is the recommended method to use in practice.     

A survey of approaches to automatic schema matching

Schema matching is a basic problem in many database application domains, such as data integration, E-business, data warehousing, and semantic query processing. In current implementations, schema matching is typically performed manually, which has significant limitations. On the other hand, previous research papers have proposed many techniques to achieve a partial automation of the match operation for specific application domains. We present a taxonomy that covers many of these existing approaches, and we describe the approaches in some detail. In particular, we distinguish between schema-level and instance-level, element-level and structure-level, and language-based and constraint-based matchers. Based on our classification we review some previous match implementations thereby indicating which part of the solution space they cover. We intend our taxonomy and review of past work to be useful when comparing different approaches to schema matching, when developing a new match algorithm, and when implementing a schema matching component. Received: 5 February 2001 / Accepted: 6 September 2001 Published online: 21 November 2001     

A protocol for performance evaluation of line detection algorithms

Accurate and efficient vectorization of line drawings is essential for any higher level processing in document analysis and recognition systems. In spite of the prevalence of vectorization and line detection methods, no standard for their performance evaluation protocol exists. We propose a protocol for evaluating both straight and circular line extraction to help compare, select, improve, and even design line detection algorithms to be incorporated into line drawing recognition and understanding systems. The protocol involves both positive and negative sets of indices, at pixel and vector levels. Time efficiency is also included in the protocol. The protocol may be extended to handle lines of any shape as well as other classes of graphic objects.     

A serial combination of connectionist-based classifiers for OCR

In this paper we describe the connectionist-based classification engine of an OCR system. The classification engine is based on a new modular connectionist architecture, where a multilayer perceptron (MLP) acting as a classifier is properly combined with a set of autoassociators – one for each class – trained to copy the input to the output layer. The MLP-based classifier selects a small group of classes with high score, that are afterwards verified by the corresponding autoassociators. The learning samples used to train the classifiers are constructed by means of a synthetic noise generator starting from few grey level characters labeled by the user. We report experimental results for comparing three neural architectures: an MLP-based classifier, an autoassociator-based classifier, and the proposed combined architecture. The experiments show that the proposed architecture exhibits the best performance, without increasing significantly the computational burden. Received March 6, 2000 / Revised July 12, 2000