Abstract:As Internet provides an open and dynamic runtime environment for distributed applications, one of the most important challenges to the next generation of middleware is how to allow the observation and manipulation of the runtime states and behaviors internal of middleware platform. Reflective middleware is able to open up the platform implementation to meet such requirements. There are three limitations in current research and experiments on reflective middleware: they focus on parts or individual entity of a system, lacking a global view; they only address the reflection of the underlying platform, ignoring the reflection of the application; they mostly experiment on CORBA with less work on J2EE. The design and implementation of a reflective component operating platform, called PKUAS, is presented. Based on its componentized structure, PKUAS introduces software architecture as the global view of the whole reflective system. As a J2EE-compliant application server, PKUAS can reflect both the underlying platform and EJB components. Moreover, this paper demonstrates the usage of reflection with the PKUAS management tool and evaluates PKUAS through comparison with other reflective middlewares. The work presented in this paper addresses the aforementioned limitations and improves the applicability of reflective middleware.

Abstract:A fast conditional breakpoint is considered to be an essential process control capability of advanced high-performance parallel debuggers. In this paper, the fundamental principles for finding and implementing fast conditional breakpoints are introduced and the design problems associated with their implementations such as code generation, code instrumentation and source program mapping are discussed. Dynamic code instrumentation, combined with hybrid code generation and source breakpoint identification, provides a well-suited solution to those problems. Using an enhanced version of the Dyninst run-time code patching library, a fast conditional breakpoint in a parallel debugger, XBUSTER, is implemented. Compared with GDB experimental results show that XBUSTER can debug a program with a higher efficiency. Compared with other fast conditional breakpoint implementations based on dynamic instrumentation technique, XBUSTER is more portable and functional.

Abstract:It is desired that time constraints of a workflow model can be measured by more than one granularities for distributed processes. Aiming at the multi-granularity time constraints problems, a workflow model, MG-TWF, is proposed. By the definition of multi-granularity relative time constraints, multi-granularity absolute time constraints and multi-granularity time constraints workflow networks, multi-granularity time constraints of MG-TWF are described from MG-TWFs static building stage, dynamic running stage and workflow networks structure. In addition, consistency analysis methods of multi-granularity relative time constraints, multi-granularity absolute time constraints and multi-granularity time constraints workflow networks are developed. Finally presented a case study is presented using the consistency analysis methods of MG-TWF.

Abstract:A weighted role for activating task and periodic time authorization is an unsolved major problem for the access control of a workflow management system (WfMS). In this paper, a novel weighted role and periodic time access control (WRPTAC) model for WfMS is proposed on the basis of a role-based access control model. The periodic time expression method is discussed and then the new authorization concepts and the temporal authorization derivation rules for WfMS are defined respectively. An algorithm based on the graph theory for verifying the consistency of all the authorization derivation rules is presented, which has the time complexity of O(n²). The constraint rule for activating task is defined, which can express complex access control constraints for WfMS.

Abstract:Most previous qualitative spatial or spatio-temporal reasoning researches focused only on one single aspect and therefore were inadequate for realistic applications. A representation and reasoning technology integrating topology, size and time information are proposed and applied to a spatio-temporal geographical information system. The representations of topology, size and time are defined and their interdependence is studied. Then an algorithm TriRSAT which can solve the CSP of these three aspects of information is put forward. The representations are used in the constraint base and the TriRSAT is applied to the consistence check of the spatial-temporal data and query. The methods and theories integrating spatio-temporal information effectively can be potentially applied to spatio-temporal database and robot navigation.

Abstract:An improved genetic algorithm based on the evolutionarily stable strategy is proposed to avoid the problem of local optimum. The key to this algorithm lies in the construction of a new mutation operator controlled by a stable factor,, which maintains the polymorphism in the colony by setting a stable factor and changing certain best seeds to mutant. Therefore, the operator can keep the number of the best individuals at a stable level when it enlarges the search space. The simulation experiments show that this algorithm can effectively avoid the premature convergence problem caused by the high selective pressure. Moreover, this algorithm improves the ability of searching an optimum solution and increases the convergent speed. This algorithm has extensive application prospects in many practical optimization problems.

Abstract:It is shown in this paper by a constructive method that for any Lebesgue integrable functions defined on a compact set in a multidimensional Euclidian space, the function and its derivatives can be simultaneously approximated by a neural network with one hidden layer. This approach naturally yields the design of the hidden layer and the convergence rate. The obtained results describe the relationship between the rate of convergence of networks and the numbers of units of the hidden layer, and generalize some known density results in uniform measure.

Abstract:Genetic drift in evolutionary computation, which results from the selection pressure, sampling error and recombination, drives the population to converge to a single individual uniformly, thus causing premature stagnation or losing alternative global or local optima. For multi-parent diagonal crossover and scanning crossover are generalizations of the various conventional crossover and recombination operators, genetic drift from which is analyzed theoretically in this paper. By analyzing the frequency of the dominant allele, it is strictly proved that multi-parent diagonal crossover and uniform scanning crossover do not cause a genetic drift, but multi-parent occurrence-based scanning crossover induces a strong genetic drift that augments with the increasing of the number of parents. The simulant genetic optimization shows that the genetic drift induced by multi-parent occurrence-based scanning crossover reduces both the population diversity and the convergence rate, thus deteriorating the performance of an evolutionary search.

Abstract:In this paper a voting algorithm is presented to mine the optimal ingredient pattern of Chinese medicine. First this paper visualizes the data about the curative effect of different prescriptions of Chinese medicine ingredients on several cardio-indexes. Then the features about the curative effect from the curves generated by visualizing the data are extracted. Finally, a voting algorithm is adopted in which votes are held in three stages: the preliminary vote generates the features of each test group and cardio-index by each sample; the metaphase vote obtains the value of the curative effect by each feature of the given group and index; the final vote mines the optimal ingredient pattern. Experimental results show that the method is effective for the kind of problems and instructive to clinic medicine experiment. Its potential applications include the development of new medicine, optimal combination investment of venture capital and gene series analysis etc.

Abstract:There exists an enormous gap between low-level visual feature and high-level semantic information, and the accuracy of content-based image classification and retrieval depends greatly on the description of low-level visual features. Taking this into consideration, a novel texture and edge descriptor is proposed in this paper, which can be represented with a histogram. Furthermore, with the incorporation of the color, texture and edge histograms seamlessly, the images are grouped into semantic classes using a support vector machine (SVM). Experiment results show that the combination descriptor is more discriminative than other feature descriptors such as Gabor texture.

Abstract:Different environment illumination has a great impact on face detection and recognition. The automatic detection and radiation correction of a highlighted face area is helpful to analyze and identify human faces correctly in a color image. In this paper, a novel approach is presented based on a dichromatic reflection model to detect and correct highlighted skin pixels in the TSL(tint-saturation-luminance) color space. After inspecting the distribution configuration of skin pixels in various color spaces and the spectrum reflection features of human skin, the authors carry out the highlighted are a analysis on a critical two-dimensional plane instead of in a three-dimensional color space, which brings forth certain advantages: computation complexity is deduced, rates between eigenvalues are produced in stepwise PCA to detect automatically the existence of highlighted skin and estimate robustly the skin dichromatic reflection vectors. The highlighted skin regions are compensated based on the dichromatic reflection model.

Abstract:Fast point multiplication on a family of Koblitz elliptic curves in characteristic 3 is considered. Such curves are suitable for establishing provable secure cryptographic schemes with low bandwidth. By utilizing the complex multiplication property of the curves and using a modulo reduction and Frobenius expansion technique, it is shown that there is a fast point multiplication method without precomputation on the curves, which is 6 times faster than the ordinary repeated-double-add method. The idea of the fast method is independent of the optimization of finite field arithmetic and the choice of coordinate expression for points of the elliptic curves.

Abstract:A new solution scheme for the member deletion problem in Camenisch-Stadler抯 group signature schemes is proposed by use of the group member抯 secret property key renew operator. In the new scheme whenever a member joins or leaves the group, its manager computes a new group public property key and a group member抯 secret property key renew operator and then publishes them. Each group member modifies the secret property key by using the renew operator without the need to re-issue membership certificates. Hence the new scheme is an acceptable solution for a large group where its membership changes frequently. The group public key, member抯 secret key, and signature are all of constant size. The new scheme is better than Bresson-Stern抯 member deletion scheme because in Bresson-Stern抯 scheme the signature is dependent on the witness and the number of the witness is linear with respect to the number of the deletion members. The idea of the key renew operator is first used in the member deletion problem in Camenisch-Stadler抯 group signature schemes by Kim-Lim-Lee, but the scheme in this paper is more concise. The security of the scheme relies on the RSA assumption. The scheme is resistant to forging attack and forging a valid signature is equivalent to solving the RSA problem.

Abstract:Nowadays, the broadband residential access infrastructure remains one of the major research areas for NGN (next generation network). Apart from popular ADSL (asymmetrical digital subscriber loop), HFC (hybrid fiber-coax) and APON (ATM passive optical network), academic communities and industry are increasingly showing great concern about Ethernet technique in the subscriber access network. This paper investigates the substantial differences among the generic broadband residential access techniques and allows a comprehensive understanding of them. The authors survey the generic broadband residential access techniques and present a comparative study on the emerging residential Ethernet-based access solutions with the ADSL, HFC, and APON techniques based on multiplex methods and transport technologies in terms of network architecture, service and traffic models, and QoS (quality of service) provisioning. The comparative study is of benefit to research and implementation of the future broadband residential access infrastructure.

Abstract:Proxy signatures are very useful tools with which a potential signer can delegate his signing power to a proxy signer who signs a message on behalf of the original signer. A blind signature is the concept with a salient feature that the signer cannot make a linkage between the blind signature and the identity of the requester. Therefore, it is very suitable for electronic commerce. On the basis of the blind Schnorr signature, this paper presents a digital proxy blind signature scheme, which satisfies the security properties of both the blind signature scheme and the proxy signature scheme.

Abstract:TTP (trusted third party) plays an important role in electronic commerce protocols. Different roles of TTP in inline TTP protocols, online TTP protocols and offline TTP protocols are pointed out through three protocols of different types, i.e., Coffey-Saidha protocol, CMP1 protocol and Asoken-Shoup-Waidner protocol. The above protocols are analyzed thoroughly, and their characteristics, defects and approaches to further improvement are discussed respectively in this paper.

Abstract:The research work of RBAC is greatly emphasized in recent years. However, the main work focuses on some characters which have nothing to do with the time character. A RBAC model with time character called TRBAC is described and the former constraint is extended so that it can describe the time character. Some algorithms are developed to solve the state change problem of the time-constraint and the sessions. The consistent state of the model is analyzed and the problem for maintaining the consistent state is discussed.

Abstract:Image, video, audio and graphics are information media in multimedia. In order to use and manage them effectively, the contents implied by them are needed to analyze. Currently, content-based image (video) and audio retrieval make some progress. However, there is no a very efficient method to perform a similar graphics retrieval, especially a similar 3D graphics retrieval. In this paper, an algorithm is presented to implement the similar 3D object recognition and retrieval. In this algorithm, 3D features are first obtained after the meshes of a 3D object are reduced through level of detail. Since the dimension of the extracted 3D features is very huge, minimum spanning tree (MST) are used to reduce the features, then the recognition of similar 3D objects are realized by Support Vector Machine (SVM). The proposed algorithm works well when it is used to recognize and retrieve a 3D terrain.

Abstract:An image coding algorithm ESPIHT (extended set partitioning in hierarchical trees) based on fast lifted wavelet transform and human visual system is proposed in this paper. It can be regarded as an improved version of the SPIHT algorithm. However, unlike SPIHT, the fast lifted wavelet transform (FLWT) is used, the extended zerotree structure is redefined, and the human visual system (HVS) is taken into account sufficiently in the compression algorithm. The experimental results show that the new image compression scheme performs better than that of SPIHT in the aspects of recovery image quality and coding/decoding time.

Abstract:Video object segmentation and stereo correspondence is a key technology in object-based stereo video coding. In this paper, based on an algorithm for extracting video object in one view-channel, a new contour tracking and correspondence algorithm is first proposed for extracting stereo video object pairs. Then, a disparity estimation algorithm based on video objects is proposed. It takes a characteristic pixel as a correspondence primitive and the disparity estimation is implemented with disparity constraints. The disadvantages of discontinuous and imprecise disparities with the traditional block-based algorithms can be improved and a precise and smooth disparity field can be finally acquired.