Showing papers in "International journal of information and management sciences in 2005"

A two phase queueing system with Bernoulli feedback

Abstract: This paper deals with an M/G/1 queue with two phases of heterogeneous services and Bernoulli feedback system, where the server provides first phase of regular service to all the customers. As soon as the first phase of service of a customer is completed, it may leave the system or may immediately go for second phase of optional service in one additional service channel. However, after receiving the first phase or second phase of unsuccessful service by an unit, then it may immediately join the tail of the original queue as feedback customer to have another regular service. In this paper, first we derive the queue size distribution at random epoch and at a service completion epoch. Secondly, we derive the distribution of response time and busy period. Finally, we present some numerical results for mean response time.

Improved inventory models with ramp type demand and weibull deterioration

Abstract: We consider inventory models with ramp type demand for items with Weibull deterioration. Wu et al. have studied these models and made excellent extensions. However, their paper contains an unnecessary condition to insure the existence of the minimum solution and only investigated the case that the inventory cycle time is longer than the period during which demand is in the increasing cycle. The purpose of this paper is twofold. First, we solve their model without the unnecessary condition. Second, we consider the general case to find the minimum solution. We offer numerical examples to illustrate our findings such that our proposed improvement indeed saves money.

An EOQ model for deteriorating items with power-form stock-dependent demand

Abstract: Datta and Pal [4] established an EOQ model in which the demand rate is a powerfunction of the on-hand inventory until down to a certain stock level, at which the demandrate becomes a constant. In this paper, we extend their EOQ model to allow for not onlydeteriorating items butalso non-zero ending inventory. Dueto the complexity of thedemandfunction,theinventoryproblemherehasthreepossiblecases. Wethenestablishthenecessaryand sucient conditions for each case. Moreover, we propose an algorithm to determine theoptimal replenishment cycle time and ordering quantity such that the total pro t per unittime is maximized. Finally, we provide some numerical examples to illustrate the proposedalgorithm, and obtain the e ects of the parameters on the replenishment time and orderingquantity. Keywords: Inventory, Deteriorating Items, Stock-Dependent Demand.1. IntroductionIn daily life, the deteriorating of goods is a common phenomenon. Pharmaceuticals,foods, vegetables and fruit are a few examples of such items. Therefore, the loss dueto deterioration cannot be neglected. Deteriorating inventory models have been widelystudied in recent years. Ghare and Schrader [6] were the two earliest researchers to

A Single Server Queue with Two Phases of Heterogeneous Service under Bernoulli Schedule and a General Vacation Time

Abstract: We consider a single server queuewith Poisson input, two phases of heterogeneous servicewith Bernoulli schedule and a general vacation time, where the server provides two phasesof heterogeneous service one after the other to the arriving customers After completion ofboth phases of service the server either goes for a vacation with probability (0    1) ormay continue to serve the next unit, if any, with probability (1 ) Otherwise, it remainsin the system until a customer arrives For this model, we rst obtain the steady stateprobability generating functions for the queue size distributions at a random epoch as wellas at a departure epoch Next, we derive the Laplace Stieltjes transform of the waitingtime distribution Finally, we obtain some system performance measures and discuss someimportant particular cases of this model Keywords: M=G=1 Queue, Two Phases of Heterogeneous Service, Bernoulli Schedule,Generalized Vacation Time, Queue Size, Waiting Time and Busy Period1 IntroductionThe single server queueing system with Bernoulli vacation is not new Keilson andServi [8] were rst to study such a model, where after each service completion the servertakes a vacation with probability  and starts a new service with probability (1 )Subsequently, Keilson and Servi [9], Ramaswamy and Servi [14], Doshi [4, 5] and Takagi[15] among others have studied this and the models of similar nature due to its numerousapplications in many real life situationsRecently Madan [11, 12] has studied two similar types of vacation models for theM=G=1 queueing system In both the models, he introduced the concept of two stage

Optimal strategy for the integrated vendor-buyer inventory model with adjustable production rate and trade credit

Abstract: In this paper we present a stylized model to find the optimal strategy for the integrated vendor-buyer inventory model with a price-sensitive market demand rate and adjustable production rate under the condition of trade credit. By analyzing total channel profit function, we developed an algorithm to simultaneously determine the buyer's optimal retail price, order quantity and the number of shipments per production run from the vendor to the buyer. The results of our analysis demonstrate that in an integrated vendor-buyer inventory model, the trade credit strategy can be a win-win business strategy for both the buyer and the vendor. Our study also identifies the total channel profit will increase while the vendor's production rate is close to the market demand rate.

A new method to construct membership functions and generate fuzzy rules from training instances

Abstract: In recent years, many methods have been proposed to deal with the Iris data classification problem. In this paper, we present a new method to deal with the Iris data classification problem by constructing membership functions and generating fuzzy rules from training instances based on the correlation coefficient threshold value ζ, the boundary shift value e and the center shift value δ, where ζ ∈ [0,1], e ∈ [0,1] and δ ∈ [0,1]. The proposed method can get a higher average classification accuracy rate than the existing methods.

Hierarchical clustering analysis based on Grey relation grade

Abstract: A new data clustering method is proposed to have some useful information in a pile of data those characters are unknown. The new data clustering method called a hierarchical grey clustering analysis is developed that need not to determine the threshold, the number of cluster, the choice of initial cluster centers and do entire comparison. In addition, for classifying data, the similar data are belonging to same group. The measurement for similarity is a globalized modified grey relation grade instead of traditional distances. The similar data with highest degree of grey relation grade are combined into the same group. Thus, decision-makers can use a tree diagram to make an appropriate decision to classify without re-computation. Hierarchical grey clustering analysis is distinguished by simplicity, effectiveness, and flexibility.

Rectifying inspection plans applied in the determination of the optimum process mean

Abstract: In this paper, we present a modified Pulak and Al-Sultan's model for determining the optimum process mean under the rectifying inspection plan. Both the lot tolerance percent defective (LTPD) protection and the average outgoing quality limit (AOQL) protection are considered in the modified model. By solving the modified model, we can obtain the optimum process mean with the maximum expected profit and the specified quality level reached.

Estimation of finite population variance in presence of random non-response using auxiliary variables

Abstract: This paper proposes some general estimators for finite population variance in presence of random non-response using an auxiliary variable. All possible non-response cases are considered here. The properties of these estimators are studied. Finally, a simulation study has been done to compare their performance.

An index for ranking fuzzy numbers by belief feature

Abstract: The aim of this paper is to explore the belief feature in ranking fuzzy algorithm, because it is a characteristic of great importance in fuzzy membership function. Currently, many algorithms adopt the concept of α-cuts to solve ranking fuzzy numbers. The calculating procedures have been largely simplified. However, these algorithms do not take the belief into account, so their fuzzy ranking theories cannot fully demonstrate the character of fuzzy membership function. In this paper, the information provided by α-cuts is discussed in the viewpoint of belief. At the same time, α-cuts fuzzy operation and belief feature are integrated to investigate the fuzzy ranking algorithm. Therefore, the algorithm presented in this paper can fully show the membership and characteristics of original fuzzy function.

A note on EOQ model under cash discount and payment delay

Abstract: In this note, we correct the models of Ouyang et al. (2002) and Chang (2002) discussed with economic order quantity (EOQ) under conditions of cash discount and payment delay. Mathematical models have been modified for obtaining the optimal cycle time and optimal payment policy for item under cash discount and payment delay so that the annual total cost is minimized. Then, we provide two theorems to efficiently determine the optimal cycle time and optimal payment policy. Finally, numerical examples are solved to illustrate the results given in the paper.

EMQ model with maintenance actions for deteriorating production system

Abstract: This paper studies the optimal production run length for the economic manufacturing quantity model with deteriorating production process and taking the restoration cost into account. We show that there exists a unique optimal production run length such that the expected total cost is minimized. In addition, bounds for the optimal production run length are provided to develop the solution procedure. Finally, a numerical example is given to illustrate the results and sensitivity analysis is performed to study the effects of changing parameters values on the optimal solution of the system.

Optimal number and capacity of servers in MX=a/M/c(∞) queueing systems

Abstract: The basic objective of the queueing theory is to determine the explicit values for different operating characteristics. Nevertheless, it should be clear that determination of the optimal number and capacity of servers must be of the same or greater importance in the numerous queueing systems in the real and virtual world. Consequently, it will be useful to show the range of server capacity, in server planning, which is optimum to be used by the specific number of servers. Therefore, this study develops an analytical methodology which analysis and plans server requirements in the queue model, with the help of bulk queueing systems and accordingly, convenient graphs are presented. The proposed method may be applied in order to determine the optimum number and capacity of servers within different transportation, communication, manufacturing, banks, management and logistics systems.

The criterion for the optimal solution of inventory model with stock-dependent consumption rate

Abstract: In 1989, Mandal and Phaujdar [Opsearch 26 43-46] considered an inventory model with stock dependent consumption rate and derived profit function without shortage allowed. However their algorithm was incomplete due to flaws in solution procedure. The purpose of this paper is to point out the sufficient and necessary condition of optimal solution to solve the same inventory model. For a linear demand rate dependent on stock level, the Newton-Raphson method is proven legitimately to find the optimal inventory level. Here we suggest an adequate starting point for the Newton-Raphson method from the Silver-Meal heuristic. Numerical examples illustrate that our starting point can be taken as an approximated solution for the optimal order quantity.

An M/G/1 queueing system with two phase service under D-policy

Abstract: This paper deals with the steady State behaviour of an M/G/1 queue with D-policy in which the server may provide an additional second phase of service. This model generalizes both classical M/G/1 queue with D-policy as well as the M/G/1 queue with classical waiting line and second optional service. We carry out an extensive analysis for the queue size distributions at different epochs. The existence of the stochastic decomposition property is also demonstrated for this model.

The impacts of warrants issuance on the price and trading volumes of the underlying stock: The call warrants case of Taiwan stock exchange

Abstract: This paper is to investigate the impacts of derivative warrants issuance from January, 1997 to April, 2001 on both price and trading volumes of underlying stock around the announcement date in Taiwan stock market. The findings on price and trading volumes behaviors suggest that there may be substantial purchases of the underlying stock by the issuers at one day before the announcement date of derivative warrants issuance for meeting the hedging demand, and there may be substantial purchases of the underlying stock by the issuer/informed-trader for the last 10 minutes prior to market closure on the announcement date of derivative warrants issuance for meeting price manipulating/information leaking demands. Nevertheless, the findings on price and trading volumes also suggest that there may convey an unfavorable signal about the reactions to the issuers' perception of future performance of the underlying stock by the public investors during two days after the announcement date of derivative warrants issuance, which underlying stock underperforms the whole market.

Using Statistical Data and Signed Distance of Fuzzy Aggregate Evaluation Method on Application of Measuring Service Quality of Hotel

Abstract: In Taiwan nowadays, many service industry sectors face intense competition and diverse customer demands, the hospitality industry has certainly not been exempted. Therefore, how to increase the competitive advantage through high service quality becomes the crucial factor in hotel industrial survival and development. Recently, many literatures focus on evaluation of service quality on hotel industry and they use statistical method to analyse the data of questionnaire with sampling. The statistical method can reveal the mean of satisfactory level of each evaluation factor, and it also shows the priority factors of the service quality for improvement. However, the satisfactory level of evaluation dimension and aggregate evaluation results can’t be achieved by using statistical method. In order to obtain the aggregate evaluation results based on statistical data, we develop a two-stage fuzzy aggregate evaluation model as a tool for the study of service quality of hotel industry. In summary, this paper provides a useful evaluation method for assessing the service quality of hotel industry.

Examination the long-run performance of Taiwanese initial public offerings

Abstract: Previous works have documented that the Taiwanese initial public offerings do not have long-run underperformance. This study demonstrates that the failure of existing studies to detect underperformance is attributed to the use of daily data, which leads to the systematic risk being underestimated, and also to the right-skewed distribution of returns. This study employs monthly trimmed return to calculate the buy-and-hold excess return and cumulative abnormal return, and finds a negative three-year abnormal return. Moreover, the calendar-time analyses of one-factor and three-factor models suggest that investors holding Taiwanese IPO shares suffer a 19% loss relative to their benchmark performance of the Taiwan stock market. This study concludes that Taiwanese IPOs suffer long-run underperformance.

Testing the goodness-of-fit of logistic models based on local linear smoothing

Abstract: For logistic regression models, a new test statistic for testing H 0 : π(x) = π 0 (x) based on nonparametric local linear regression technique is proposed. Smoothing methods can be used to define a goodness-of-fit test that does not suffer from the drawbacks of current goodness-of-fit methods for logistic models. The motivation of applying local smoother is explained. Mean and variance of the proposed test statistic are given in explicit expression. The properties of the test statistic are also discussed by simulation.

A Parallel Algorithm for Static Program Slicing

Abstract: Program slicing is the process of deleting statements in a program that do not aect a given set of variables at a chosen point in the program. In this paper the parallel slicing algorithm is introduced. It is shown how the control o w graph of the program to be sliced is converted into a network of concurrent processes, thereby producing a parallel version of Weiser’s original static slicing algorithm. Keywords:

Transient solution of a correlated queueing problem with variable capacity and catastrophes

Abstract: In this paper, we develop a continuous time, correlated arrivals queuing model with variable capacity and catastrophes for the cell traffic generated by New Broadband Communication Networks in presence of viruses and noise bursts. Transient solution of the model has been obtained using probability generating function technique. Finally some particular cases are derived.

The efficiency comparison on Warner's and two modified models

Abstract: Using jeopardy function [3], this paper explores the efficiency comparison on three well-known models presented by Warner [5], Mangat et al. [4], Bhargava and Singh [2] respectively, which all are to solve a sensitivity problem. Based on the concept of jeopardy function, we find under what conditions that Bhargava and Singh's model is the best among these three models.

A New Approach Solving a Two-Node Closed Queueing Network

Abstract: In this paper, a general approach to solve a closed queueing network of two nodes in which the service times are of the phase type is considered. The Laplace-Stieltjes Transforms of service time distributions satisfying a system of equations is presented rst. According to state balance equations, the stationary probabilities on the unboundary states can be shown as a linear combination of Kronecker product-forms. Each component of these products can be expressed in terms of roots of an associated characteristic polynomial. Furthermore, a procedure for solving stationary probabilities can be presented. The complexity of this approach that is independent of the number of customers in the system is proved. Consequently, the computational complexity for a general closed queueing network can be reduced.

Computational efficiency of shortest path algorithms in C language

Abstract: The main purpose of this study is to evaluate the computational efficiency of algorithms for calculating shortest paths when they are correctly coded by using the C programming language. This paper thoroughly measures the benefit of using the C programming language for coding shortest path algorithms. For each algorithm, we suggest computer implementation that take full advantage of the pointer capabilities of C. Our study establishes the relative order of the shortest path algorithms with respect to their known computational efficiencies is not significantly modified when the algorithms are adequately coded in C. However, the reward of using the C programming language is a speedup factor of about 20%. In some cases, it reaches to 30%. An important contribution of this study is the inclusion of the redistributive heap algorithm. In spite of having its best theoretical efficiency, the redistributive heap algorithm does not emerge as the best method in terms of computational efficiency.

The relation between cost and yield rate in a JIT production system

Abstract: In this paper we consider production economic and cost related yield rate in a JIT (Just in Time) system. Based on the traditional EPQ (Economic Production Quantity) model, we establish the relation between cost and yield rate. The geometric programming approach is applied in our model to solve this optimizing posynomials problem. A numerical example is carried out to verify the proposed model. Through this paper, we connect the cost and yield rate in a JIT production system. This study demonstrates the power and efficiency of the geometric programming approach for the particular type of EPQ problem.