26267867
Optimal Bayesian sampling acceptance plan with random censoring
Abstract The sampling acceptance scheme with censoring is one of the important life inspection problems. In this article, a general model of sampling acceptance plan for the exponential distribution with exponentially distributed random censoring is presented and investigated using Bayesian decision theory. We consider a loss function which includes the sampling cost, time-consuming cost and decision loss to determine the optimal sampling acceptance plan. Under mild assumptions, the optimal Bayes rule can be proved to be of a monotonic form. Moreover, we obtain optimal Bayes rules and explicit expressions of the Bayes risk for two special decision loss functions. Finally, a numerical example is given to demonstrate the model.
12151643
Discretization Approach and Nonparametric Modeling for Long-Term HIV Dynamic Model
Modeling viral load response in long-term HIV dynamics is important for AIDS clinical study. It allows one to examine how a patient recuperates for an antiviral treatment. This paper investigates a discretization approach to the viral load based on a long-term HIV dynamic model. We propose a two-stage nonparametric procedure for estimating the viral load and the time-varying new productive virus. Simulation study shows that the proposed estimated methods are efficient and powerful for fitting long-term viral load measurements.
41316192
Efficient Learning of Pseudo-Boolean Functions from Limited Training Data
Pseudo-Boolean functions are generalizations of Boolean functions. We present a new method for learning pseudo-Boolean functions from limited training data. The objective of learning is to obtain a function f which is a good approximation of the target function f*. We define suitable criteria for the “goodness” of an approximating function. One criterion is to choose a function f that minimizes the “expected distance” with respect to a distance function d (over pairs of pseudo-Boolean functions) and the uniform distribution over all feasible pseudo-Boolean functions. We define two alternative “distance measures” over pairs of pseudo-Boolean functions, and show that they are are actually equivalent with respect to the criterion of minimal expected distance. We outline efficient algorithms for learning pseudo-Boolean functions according to these criteria. Other reasonable distance measures and “goodness” criteria are also discussed.
20756797
Algebraic specification of interconnection network relationships by permutation voltage graph mappings
Symmetries of large networks are used to simplify the specification of a guest-host network relationship. The relevant kinds of symmetries occur not only in Cayley graphs and in group-action graphs, but elsewhere as well. In brief, the critical topological symmetry property of a guest or host is that it is algebraically specifiable as a covering space of a smaller graph. A first objective is to understand the circumstances under which a mapping (a.k.a. “embedding”) between two base graphs can be lifted topologically to a mapping between their respective coverings. A suitable assignment of algebraic elements called “permutation voltages” to a base graph for the intended host network facilitates the construction not only of the intended host, but also of the intended guest and of the intended mapping of the guest into the host. Explicit formulas are derived for measurement of the load, of the congestion, and of the dilation of the lifted mapping. A concluding example suggests how these new formulas open the opportunity to develop optimization methods for algebraically specified guest-host mappings.
12385194
Key research issues in grid workflow verification and validation
In the grid architecture, a grid workflow system is a type of high-level grid middleware which is supposed to support modelling, redesign and execution of large-scale sophisticated e-science and e-business processes in many complex scientific and business applications. To ensure the correctness of grid workflow specification and execution, grid workflow verification and validation must be conducted so that we can identify any violations and consequently take proper action to remove them in time. However, current research on the grid workflow verification and validation is just at the early stage and very few projects focus on them. Therefore, a systematic identification of key research issues in the grid workflow verification and validation field is no doubt helpful and should be presented so that we can be on the right track and reduce unnecessary work as far as possible. Hence, in this paper, we systematically analyse the grid workflow verification and validation and investigate their key research issues. Especially, we identify some important open research points which are not discussed by the current research and hence need further investigation. All these analyses form a big picture for the grid workflow verification and validation.
16407407
An interactive method for fuzzy multiple attribute group decision making
In this paper, we develop an interactive method for multiple attribute group decision making under fuzzy environment. The method can be used in situations where the information about attribute weights is partly known, the weights of decision makers are expressed in exact numerical values or triangular fuzzy numbers, and the attribute values are triangular fuzzy numbers. The method transforms fuzzy decision matrices into their expected decision matrices, constructs the corresponding normalized expected decision matrices by two simple formulas, and then aggregates these normalized expected decision matrices into a complex decision matrix. Moreover, the decision makers are asked to provide their preferences gradually in the course of interactions. By solving linear programming models, the method diminishes the given alternative set gradually, and finally finds the most preferred alternative. By using the method, the decision makers can provide and modify their preference information gradually in the process of decision making so as to make the decision result more reasonable. The method can not only reflect the importance of the given arguments and the ordered positions of the arguments, but also relieve the influence of unfair arguments on the decision result. Finally, a practical problem is used to illustrate the developed method.
34139794
Integrating Sample-Driven and Pattern-Driven Approaches in Motif Finding
The problem of finding conserved motifs given a set of DNA sequences is among the most fundamental problems in computational biology, with important applications in locating regulatory sites from co-expressed genes. Traditionally, two classes of approaches are used to address the problem: sample-driven approaches focus on finding the locations of the motif instances directly, while pattern-driven approaches focus on finding a consensus string or a profile directly to model the motif. We propose an integrated approach by formulating the motif finding problem as the problem of finding large cliques in k-partite graphs, with the additional requirement that there exists a string s (which may not appear in the given sample) that is close to every motif instance included in such a clique. In this formulation, each clique represents the locations of the motif instances, while the existence of string s ensures that these instances are derived from a common motif pattern. The combined approach provides a better formulation to model motifs than using cliques alone, and the use of k-partite graphs allows the development of a fast and exact divide-and-conquer approach to handle the cases when almost every sequence contains a motif instance. Computational experiments show that this approach is feasible even on the most difficult motif finding problems of moderate size. When many sequences do not contain a motif instance, we complement the above approach by an optimized branch-and-bound algorithm that is much faster than standard clique finding approaches. We will discuss how to further generalize the formulation to better model biological reality.