A moment generating function based approach for evaluating extendedstochastic Petri Nets

A moment-generating-function (MGF)-based approach for performance analysis of extended stochastic Petri nets (ESPNs) is presented. The method integrates Petri nets, MGF and stochastic network concepts, and Mason's rule into a tool for evaluating various discrete-event dynamic systems. The ESPNs are modeled, given the specification of a system. Then, the state machine PN is derived, the transfer functions based on the MGFs of the related transitions are found, the network is reduced to a single transition with its transfer function for each performance measure, and system performance is calculated. Firing delays of transitions in ESPNs can be either deterministic or stochastic with an extended distribution. Three fundamental structures that can be reduced into a single transition are discussed. The machine-repairman model with a buffer is given as an example to illustrate the method for evaluating performance parameters     

A general RBDO decoupling approach for different reliability analysis methods

There are available in the literature several papers on the development of methods to decouple the reliability analysis and the structural optimization to solve RBDO problems. Most of them focused on strategies that employ the First Order Reliability Method (FORM) to approximate the reliability constraints. Despite of all these developments, one limitation prevailed: the lack of accuracy in the approximation of the reliability constraints due to the use of FORM. Thus, in this paper, a novel approach for RBDO is presented in order to overcome such a limitation. In this approach, we use the concept of shifting vectors, originally developed in the context of the Sequential Optimization and Reliability Assessment (SORA). However, the shifting vectors are found and updated based on a novel strategy. The resulting framework is able to use any technique for the reliability analysis stage, such as Monte Carlo simulation, second order reliability methods, stochastic polynomials, among others. Thus, the proposed approach overcomes the aforementioned limitation of most of RBDO decoupling techniques, which required the use of FORM for reliability analysis. Several examples are analyzed in order to show the effectiveness of the methodology. Focus is given on examples that are poorly solved or even cannot be tackled by FORM based approaches, such as highly nonlinear limit state functions comprised by a maximum operator or problems with discrete random variables. It should be remarked that the proposed approach was not developed to be more computationally efficient than RBDO decoupling strategies based FORM, but to allow the utilization of any, including more accurate, reliability analysis method.     

A new hybrid model of information entropy and unascertained measurement with different membership functions for evaluating destressability in burst-prone underground mines

The occurrence of unpredictable hazards are frequent with the increased depth of mining, especially the hazards caused by stress concentration. In order to mitigate the negative effectiveness results from mining-induce stress, various approaches have been employed in underground mines. Destress blasting, as an efficient method, has gained a lot of popularity in recent years. However, it is crucial to estimate the destressability of specific area before conducting destress blasting. In this study a combination model on the basis of both unascertained measurement (UM) and entropy coefficients was applied to observe the performance of destressability evaluation. Eight representative parameters, i.e., stiffness of the rock mass, brittleness of the rock mass, degree of fracturing, proximity to failure, destress blast orientation, width of the target zone, unit explosive energy, and confinement of the charges were chosen as initial input parameters, and their membership distributions were described by four types of membership methodologies, i.e., line, parabolic curve, exponential curve, and sine curve. Meanwhile, the weights of each index could be computed based on the single measurement matrix. Then, destressability of the samples was easily identified with Euclidean distance and comprehensive measurement vectors which were computed by single measurement vectors and weight coefficients. Finally, it was found that the assessment results are in accordance with those calculated by destressability index. It can be concluded that the proposed hybrid model is able to eliminate the disturbance of subjective factors and ensure the reliability of these outcomes. At the same time, it can provide a novel idea/process for the destressability evaluation.

     

A Bayesian approach to information fusion for evaluating the measurement uncertainty

The Bayesian approach to uncertainty evaluation is a classical example of the fusion of information from different sources. Basically, it is founded on both the knowledge about the measurement process and the influencing quantities and parameters. The knowledge about the measurement process is primarily represented by the so-called model equation, which forms the basic relationship for the fusion of all involved quantities. The knowledge about the influencing quantities and parameters is expressed by their degree of belief, i.e. appropriate probability density functions that usually are obtained by utilizing the principle of maximum information entropy and the Bayes theorem. Practically, the Bayesian approach to uncertainty evaluation is put into effect by employing numerical integration techniques, preferably Monte-Carlo methods. Compared to the ISO-GUM procedure, the Bayesian approach does not have any restrictions with respect to nonlinearities and calculation of confidence intervals.     

A novel approach for capturing and evaluating dynamic consumer requirements in open design

In the product design, understanding consumer requirements (CRs) is essential due to the fact that it influences the success of the product. Currently, it has been recognized that consumer involvement in an open design (OD) environment is an effective way to reduce the gap between what is required by consumers and what companies can provide. In the process of OD, the initial CRs may shift as the consumers can influence each other, and it is a challenge to capture and evaluate dynamic CRs in OD. In this study, the dynamic relationship between consumers who participate in OD is discussed based on Nash equilibrium. Corresponding to the dynamic relationship, a novel approach is proposed to explore the crucial CRs from consumers’ perspective. Initially, the platform of OD is constructed on the Internet to collect the CRs and its evaluations. Thereafter, a similarity-based filtering method (SFM) is presented to filter out the most differentiated evaluations. Furthermore, to get the weight of the CR evaluated by consumers, an improved fuzzy Delphi method is introduced. Meanwhile, to solve the problem of excessive number of CRs, a dual-index evaluation method is put forward to control the opening degree of OD. Finally, to demonstrate the applicability of the suggested approach, a product of smartphone is examined as a case study. The results confirm that the proposed approach is appropriate for capturing and evaluating dynamic CRs in OD.     

A novel approach to determination of a transition function with repeated eigenvalues constant matrix

An analytical function of a matrix with repeated eigenvalues is expressed in terms of constituent matrices. Two approaches to computing the constituent matrices are then presented. For a special case of a companion matrix, the computation can be greatly simplified.     

A general approach to classification problems

In the classification problem the value of the discrete random variable I must be estimated from that of a random variable X given a random sample (I₁, X₁),(I₂, X₂),…,(I_n, X_n). A classification rule giving such an estimate can be based on most nonparametric density estimators which are based on delta sequences. The rate at which the nonerror rate for this rule converges to the optimal is calculated. It is found to be $\text{O(n}{}^{\mathrm{<mtext>?1</mtext><mtext>(2d\; +\; 2)</mtext>}}\text{log}{}^{\mathrm{d}}\text{n}$, where d is the dimension of the variable X under mild assumptions on the densities. A procedure for choosing an associated parameter for small samples is given.     

赋工序完工隶属函数的网络计划模型

文中为处理网络计划模型中工序作业时间的不确定性,提出了用工序完工隶属函数描述作业时间不确定性,并给出了求工程的完工隶属函数的方法,最后说明了利用工程的完工隶属函数进行关键路线分析。     

A group decision support approach to evaluating journals

One of the most important decisions made in academic institutions, research organizations, and government agencies is the grading or ranking of journals for their academic values. Current methods for evaluating journals use either a subjective (e.g., experts’ judgments on journals) or objective approach (e.g., impact factors of journals), or an informal mix of the two. This paper presents a formal procedure that integrates objective and subjective judgments to provide a comprehensive method. The procedure is based on a fuzzy set approach that deals with the imprecise and missing information inherent in the evaluation process. The system was tested in Hong Kong in an assessment of faculty research productivity. Similar assessments exist in the UK, Singapore, and other countries. The proposed model can also be used for similar decisions that involve subjective and objective information.     

A group decision support approach to evaluating journals

One of the most important decisions made in academic institutions, research organizations, and government agencies is the grading or ranking of journals for their academic values. Current methods for evaluating journals use either a subjective (e.g., experts’ judgments on journals) or objective approach (e.g., impact factors of journals), or an informal mix of the two. This paper presents a formal procedure that integrates objective and subjective judgments to provide a comprehensive method. The procedure is based on a fuzzy set approach that deals with the imprecise and missing information inherent in the evaluation process. The system was tested in Hong Kong in an assessment of faculty research productivity. Similar assessments exist in the UK, Singapore, and other countries. The proposed model can also be used for similar decisions that involve subjective and objective information.     

A factorization approach to evaluating simultaneous influence diagrams

Evaluating an influence diagram (ID) is a challenging problem because its complexity increases exponentially in the number of decision nodes in the diagram. In this paper, we examine the problem for a special class of IDs where multiple decisions must be made simultaneously. We describe a brief theory that factorizes out the computations common to all policies in evaluating them. Our evaluation approach conducts these computations once and uses them across all policies. We identify the ID structures for which the approach can achieve savings. We show that the approach can be used to efficiently recompute the optimal policy of an ID when its structure or parameters change. Finally, we demonstrate the superior performance of the approach by simulation studies and a military planning example.     

A statistical approach to the generation of a database for evaluating OCR software

In this paper we consider a statistical approach to augment a limited database of groundtruth documents for use in evaluation of optical character recognition software. A modified moving-blocks bootstrap procedure is used to construct surrogate documents for this purpose which prove to serve effectively and, in some regards, indistinguishably from groundtruth. The proposed method is validated through a rigorous statistical procedure. Received: March 30, 2000 / Revised: September 14, 2001     

A general approach for token correspondence

This paper presents a generalization of the correspondence approach of I. K. Sethi and R. Jain (IEEE Trans. Pattern Anal. Mech. Intell. 9, 56–73, 1987), by extending the path coherence criterion to high dimensional vector spaces, where tokens are represented as points. Two algorithms for obtaining correspondence of tokens are described. Experimental results for line and region tokens are presented to demonstrate the general purpose nature of the proposed correspondence approach.     

A Model-based approach for the synthesis of software to firmware adapters for use with automatically generated components

This paper presents the MDE process in use at Elettronica SpA (ELT) for the development of complex embedded systems integrating software and firmware. The process is based on the adoption of SysML as the system-level modeling language and the use of Simulink for the refinement of selected subsystems. Implementations are generated automatically for both the software (C++ code) and firmware parts, and communication adapters are automatically generated from SysML using a dedicated profile and open-source tools for modeling and code generation. The process starts from a SysML system model, developed according to the platform-based design paradigm, in which a functional model of the system is paired to a model of the execution platform. Subsystems are refined as Simulink models or hand-coded in C++. An implementation for Simulink models is generated as software code or firmware on FPGA. Based on the SysML system architecture specification, our framework drives the generation of Simulink models with consistent interfaces, allows the automatic generation of the communication code among all subsystems (including the HW–FW interface code). In addition, it provides for the automatic generation of connectors for system-level simulation and of test harnesses and mockups to ease the integration and verification stage. We provide early results on the time savings obtained by using these technologies in the development process.     

A first-pass approach for evaluating machine translation systems

This paper describes a short-term survey and evaluation project that covered a large number of machine translation products and research. We discuss our evaluation approach and address certain issues and implications relevant to our findings. We represented a variety of potential users of MT systems and were faced with the task of identifying which systems would best help them solve their translation problems.     

A group-decision approach for evaluating educational web sites

With the advent of network technologies, many educational web sites have been developed to assist students in the learning of subjects on computer networks. However, without proper aid, students may have difficulty in selecting appropriate web sites, that are of benefit to them; hence, studying, evaluating and recommending educational web sites has become an important and challenging issue. In this paper, a group-decision approach is proposed for evaluating educational web sites. Several soft computing technologies have been employed in the approach, including fuzzy theory, grey system and group decision method. A computer-assisted web site evaluation system, EWSE (Educational Web Site Evaluator), has been developed, based on an experimental approach, which is capable of selecting the proper criteria for an individual web site and achieves greater accuracy when evaluating results.     

A quantitative approach for evaluating the quality of design patterns

In recent years, the influence of design patterns on software quality has attracted an increasing attention in the area of software engineering, as design patterns encapsulate valuable knowledge to resolve design problems, and more importantly to improve design quality. As the paradigm continues to increase in popularity, a systematic and objective approach to verify the design of a pattern is increasingly important. The intent session in a design pattern indicates the problem the design pattern wants to resolve, and the solution session describes the structural model for the problem. When the problem in the intent is a quality problem, the structure model should provide a solution to improve the relevant quality. In this work we provide an approach, based on object-oriented quality model, to validate if a design pattern is well-designed, i.e., it answers the question of the proposed structural model really resolves the quality problems described in the intent. We propose a validation approach to help pattern developers check if a design pattern is well-designed. In addition, a quantitative method is proposed to measure the effectiveness of the quality improvement of a design pattern that pattern users can determine which design patterns are applicable to meet their functional and quality requirements.     

A general approach to the fusion of imprecise information

We consider the problem of fusion of multiple information sources, particularly in environments when the sensor observations are imprecise. The concept of a combinability relationship is introduced to enable the inclusion in the fusion process of information about the appropriateness of fusing different elements from the observation space. This idea allows for the use of an expert knowledge base, containing information about the domain of the particular problem, in the fusion process and leads to a more intelligent aggregation. We show that if we use a combinability relationship that only allows fusion of identical elements then the only idempotent fusion of any collection of fuzzy observations is their intersection. Using the idea of the fuzzy measure we considered situations in which we allow a partial collection of the observations determine the fused value. © 1997 John Wiley & Sons, Inc.     

A new convex-hull based approach to evaluating flatness tolerance

In this paper, we consider a minimum-zone evaluation problem for flatness to determine the minimum tolerance zone enclosing all the measurement points obtained from a surface. For the problem, a new geometric approach called the ‘convex-hull edge method’ (CONHEM) is proposed. The method guarantees the minimum zone tolerance for a given set of measurement points. Several examples discussed by other researchers are illustrated to compare the method with some existing approaches.