DSpace collection: 第27卷第3期

Standby System with Imperfect Coverage and Repairable Service Station

title: Standby System with Imperfect Coverage and Repairable Service Station abstract: This paper analyzes the reliability characteristics of a system with imperfect coverage in which a repairable service station is considered. Failure times of primary and standby units are assumed to follow exponential distributions. With a coverage probability c, a failed unit is immediately detected and replaced by a standby if one is available. If the failed unit is not detected, the system enters an unsafe failure state and has to be refreshed by a reboot action. When the service station breaks down, it needs repair at a repair device. We present the expression for reliability function RY (t) and mean time to system failure MT T F. Several cases are analyzed to study the effects of various parameters on the system reliability RY (t) and MT T F. We also perform the sensitivity analysis of RY (t) and MT T F with respect to system parameters. Finally, we present an application example to demonstrate the applicability of investigated model.

Two-Period Pricing Model for Walk-in Potential Consumers with Normal Distribution of the Price of Their Willing to Buy

title: Two-Period Pricing Model for Walk-in Potential Consumers with Normal Distribution of the Price of Their Willing to Buy abstract: The optimal model was mainly constructed for the products, such as real estates, amusement park, or major furniture which themselves cannot be moved or worn to reveal to other consumers in public, to explain their optimal promotional pricing strategy. The study adopted the dual sources of the diffusion power, the number of walk-in potential consumers and the price level of the product, in the extended Bass Diffusion Model. Given periods of [0, T ) and [T, T¯), T < T¯, and T¯ maybe ∞ when a firm attempts to decide price P0 within [0, T ) and price PT within [T, T¯), respectively, to achieve the goal of maximizing discounted profit in the interval [0, T¯), the characteristics of its optimal solution (P ∗ 0 , P∗ T ) at each period were rigorously derived and profoundly discussed. This two-period model pricing could be extended to an infinite multiple-period optimal pricing model to become the issue of price control. The study would further conclude that, after a new product is initialized, its price should decline with time to take advantage of it with exhausting the consumer surplus of consumers.

Reliability Evaluation of a Multicommodity Capacitated-Flow Network in Terms of Minimal Pathsets

title: Reliability Evaluation of a Multicommodity Capacitated-Flow Network in Terms of Minimal Pathsets abstract: Many real-world systems such as transportation systems, logistics/distribution systems, and manufacturing systems can be regarded as multicommodity flow networks whose arcs have independent, finite and multi-valued random capacities. Such a flow network is a multistate system with multistate components and its reliability for level d = (d1, d2, . . . , dk), i.e., the probability that k different types of commodity can be transmitted from the source node to the sink node in the way that the demand level d = (d1, d2, . . . , dk) is satisfied, can be computed in terms of minimal path vectors to level d (named d-MPs here). The main objective of this paper is to present a simple algorithm to generate all d-MPs of such a flow network for each level d = (d1, d2, . . . , dk) in terms of minimal pathsets. Three examples are given to illustrate how all d-MPs are generated by our algorithm and then the reliability of one example is computed.

A New Approach in Multiple Attribute Decision Making using R-norm entropy and Hamming Distance Measure

title: A New Approach in Multiple Attribute Decision Making using R-norm entropy and Hamming Distance Measure abstract: The theory of intuitionistic fuzzy (IF) set is well suitable to deal with the vagueness and hesitancy. In the present communication, we have considered R-norm entropy with both uncertainty and hesitancy degree of an IF set. Using this R-norm entropy, we have solved a multiple attribute decision making (MADM) problem in which attribute values are expressed with IF values. In MADM problem, we mainly encounter with two types of problems. First is when we don’t have any information regarding attribute weights and second is when we have little information about weights, i.e., they are partially known to us. In this paper, we have considered both the cases with examples. For the first case, we have used an extension of entropy weight method to calculate the attribute weights and in second case attribute weights are calculated by using the minimum entropy principle method which is based on solving a linear programming model. The two methods are effectively explained by taking real life examples. Also the two examples are calculated by using the TOPSIS method suggested by Chen and Tsao and shown that the outputs of both the methods coincide.

Stationary Queue Length Distribution for a Discrete-Time Preemptive Priority Queue

title: Stationary Queue Length Distribution for a Discrete-Time Preemptive Priority Queue abstract: This paper considers a discrete-time Geo/Geo/1 preemptive priority queue with two classes of customers. The queue system can be modeled by a quasi-birth-and-death (QBD) process with infinitely many phases. For the QBD process, we obtain explicit form of the joint stationary distribution and then we also get the stationary queue length distribution for lower-priority customers.