This paper studied the flow shop scheduling problem under machine availability constraints. The machines are subject to flexible preventive maintenance activities. The nonresumable scenario for the jobs was considered. That is, when a job is interrupted by an unavailability period of a machine it should be restarted from the beginning. The objective is to minimize the total tardiness time for t...

BACKGROUND Case cancellation can be very distressing not only to the patient and relatives but also to health care professionals. OBJECTIVES This study aims at detecting the causes of case cancellations on the intended day of surgery (DOS) at a tertiary hospital in Enugu that handles both elective and emergency cases. METHODS The data was extracted retrospectively from the anesthetists' dai...

The authors present the central capacity sharing (CCS) model and derive equations describing its behaviors to explain results from dual-task situations. The predictions of the CCS model are contrasted with those of the central bottleneck model. The CCS model predicts all of the hallmark effects of the psychological refractory period (PRP) pardigm: -1 slope of the PRP effect at short stimulus on...

Stimuli that are clearly positive or negative (hence valence-laden stimuli) have the potential to interrupt unrelated task processing. A typical example is the emotional Stroop effect (ESE) in which responding to a certain task feature (e.g., color) is delayed by the presentation of task-irrelevant valent stimuli (e.g., negative pictures) compared to valence-neutral stimuli. Here we scrutinize ...

The paper presents a new analytical algorithm which is able to carry out direct and exact reliability quantification of highly reliable systems with maintenance (both preventive and corrective). A directed acyclic graph is used as a system representation. The algorithm is based on a special new procedure which permits only summarization between two or more nonnegative numbers that can be very d...

Abstract. Given a doubling measure μ on R, it is a classical result of harmonic analysis that Calderón-Zygmund operators which are bounded in L(μ) are also of weak type (1, 1). Recently it has been shown that the same result holds if one substitutes the doubling condition on μ by a mild growth condition on μ. In this paper another proof of this result is given. The proof is very close in spirit...

A change in subtask order in the psychological refractory period (PRP) paradigm increases the effect of stimulus onset asynchrony (SOA) on the second response. We used a paradigm with cued, randomly determined subtask order to test the hypothesis that this SOA by order switch overadditivity reflects order control, via "copying" stimulus order. In Experiments 1a and 1b, overadditivity was eviden...

Although a large body of literature has suggested that doctoral supervisors play an important role in their students’ attempts at scholarly publishing, few studies have focused specifically on what roles they play. This study sought to address this gap by zooming in on the various roles a group of Chinese doctoral students found their supervisors playing in their scholarly publishing endeavors....