This paper presents a mathematical model for an inventory control system in which customers’ demands and suppliers’ service time are considered as stochastic parameters. The proposed problem is solved through queuing theory for a single item. In this case, transitional probabilities are calculated in steady state. Afterward, the model is extended to the case of multi-item inventory systems. The...

Our aim is to maximize expected profit per item of a multi-stage production system by determining best adjustment points of the equipments used based on technical product specifications defined by designer. In this system, the quality characteristics of items produced should be within lower and higher tolerance limits. When a quality characteristic of an item either falls beneath the lower li...

BACKGROUND: Quality of life is an important concept which is subjective and personal; what is an acceptable quality of life to one may be 'worse than death' to another. The objective of this study was to develop and validate a questionnaire to assess relatives' perceptions and attitudes towards their terminal stage cancer patients' management (information disclosure, treatment choice, hospitali...

BACKGROUND The objective of this study was to examine whether a widely available single-item measure of sleep disturbances is an acceptable alternative to a multi-item sleep questionnaire. METHODS Data were derived from Finnish Helsinki Health Study postal questionnaires administered in 2000-2002 (n = 7777, response rate 67%). The measures were the 4-item Jenkins Sleep Questionnaire (JSQ) on ...

A reranking algorithm, Multi-Rerank, is proposed to refine the recommendation list generated by collaborative filtering approaches. MultiRerank is capable of capturing multiple self-contained modalities, i.e., item modalities extractable from user-item matrix, to improve recommendation lists. Experimental results indicate that Multi-Rerank is effective for improving various CF approaches and ad...