In the recent years, constraint programming has been applied to a wide variety of academic and industrial non-preemptive scheduling problems, i.e., problems in which activities cannot be interrupted. In comparison, preemptive scheduling problems have received almost no attention from both the Operations Research and the Artificial Intelligence community. Motivated by the needs of a specific app...

Abstract: Research on due date oriented objectives in the parallel machine environment is at best scarce compared to objectives such as minimizing the makespan or the completion time related performance measures. Moreover, almost all existing work in this area is focused on the identical parallel machine environment. In this study, we leverage on our previous work on the single machine total we...

A retrospective study was performed to collect information regarding efficacy and toxicity of cidofovir (CDV) in allogeneic stem cell transplant patients. Data were available on 82 patients. The indications for therapy were cytomegalovirus (CMV) disease in 20 patients, primary preemptive therapy in 24 patients, and secondary preemptive therapy in 38 patients. Of the patients, 47 had received pr...

BACKGROUND AND OBJECTIVE Our objective was to report on the design and essentials of the Etoricoxib protocol- Preemptive and Postoperative Analgesia (EPPA) Trial, investigating whether preemptive analgesia with cox-2 inhibitors is more efficacious than placebo in patients who receive either laparotomy or thoracotomy. DESIGN AND METHODS The study is a 2 x 2 factorial armed, double blinded, bic...

The reliability of preemptive analgesia is controversial. Its effectiveness may vary among anatomical areas or surgical types. We evaluated preemptive analgesia by epidural morphine in six surgery types in a randomized, double-blind manner. Pain intensity was rated using a visual analog scale, a verbal report, and a measurement of postsurgical morphine consumption. Preemptive analgesia was effe...

We derive recursive formulas for computing the state probabilities in priority queueing systems (preemptive and non-preemptive). The derivation is based only on the general structure of the generating function involved, and thus is simpler and more general than previous methods. We also discuss the applications of our method to other queueing systems.

We consider scheduling on a single machine with one non-availability period to minimize the weighted sum of completion times. We provide a preemptive algorithm with an approximation ratio arbitrarily close to the Golden Ratio, (1+ √ 5)/2+ε, which improves on a previously best known 2approximation. The non-preemptive version of the same algorithm yields a (2 + ε)-approximation.

The problem of nding a large independent set in a hyper-graph by an online algorithm is considered. We provide bounds for the best possible performance ratio of deterministic vs. randomized and non-preemptive vs. preemptive algorithms. Applying these results we prove bounds for the performance of online algorithms for routing problems via xed paths over networks.

This paper presents a Probabilistic Preemptive (PP) scheduling discipline for service differentiation in Optical Burst Switching (OBS) networks. The main idea of PP is that a probabilistic parameter is added to the preemptive scheduling discipline. With PP, a high priority burst preempts a low priority burst in a probabilistic manner. By changing the probabilistic parameter, PP can achieve flex...

In this paper we implement the EDF-VD (Earliest Deadline First with Virtual Deadline) algorithm described in [1] for scheduling mixed-criticality, realtime task systems on preemptive uniprocessor platforms. We compare the scheduling overheads of this algorithm with the scheduling overheads of the well known EDF (Earliest Deadline First) algorithm for scheduling realtime task systems on preempti...