BACKGROUND Adequate participant recruitment is vital to the conduct of a clinical trial. Projected recruitment rates are often over-estimated, and the time to recruit the target population (accrual period) is often under-estimated. METHODS This report illustrates three approaches to estimating the accrual period and applies the methods to a multi-center, randomized, placebo controlled trial u...

In Indonesia, the fund for a project or an activity is usually divided into terms which can be two or three terms. Therefore, in order to optimize the utility, the team of the project need to design the project so that the project can be used as soon as possible without violating the restriction given by the government. The Multi Periods Degree Constrained Minimum Spanning Tree Problem (MPDCMST...

In this paper, a tour-based multi-objective logistics model for optimized scheduling of the delivery of critical items in a disaster relief operation is proposed. Our model considers multi-items, multi-vehicles, multi-periods, and a split delivery scenario in a disaster. Two heuristic approaches are introduced to solve the logistics problem. In the first approach, a genetic algorithm is applied...

A literature review of 105 studies on the effects of extended daily working hours was conducted. Potential negative effects of extended working hours are discussed: More accidents on the job; more accidents off the job; reduced duration and quality of sleep due to moonlighting; sleepiness; reduced alertness; fatigue; adverse effects on performance; prolonged toxic exposure; adverse effects on h...

In scheduling literature, the notion of machine non-availability periods is well known, for instance for maintenance. In our case of planning chemical experiments, we have special periods (the week-ends, holidays, vacations) where the chemists are not available. However, human intervention by the chemists is required to handle the starting and termination of the experiments. This gives rise to ...

© Foundation Compositio Mathematica, 1996, tous droits réservés. L’accès aux archives de la revue « Compositio Mathematica » (http: //http://www.compositio.nl/) implique l’accord avec les conditions générales d’utilisation (http://www.numdam.org/legal.php). Toute utilisation commerciale ou impression systématique est constitutive d’une infraction pénale. Toute copie ou impression de ce fichier ...

We define motivic multiple polylogarithms and prove the double shuffle relations for them. We use this to study the motivic fundamental group π 1 (Gm −μN ), where μN is the group of all N -th roots of unity, and relate the structure of π 1 (Gm − μN ) to the geometry and topology of modular varieties Xm(N) := Γ1(m;N)\GLm(R)/R ∗ + ·Om for m = 1, 2, 3, 4, .... We get new results about the action o...

We give an elementary short proof for a well-known theorem of Guibas and Odlyzko stating that the sets of periods of words are independent of the alphabet size. As a consequence of our constructing proof, we give a linear time algorithm which, given a word, computes a binary one with the same periods. We give also a very short proof for the famous Fine and Wilf's periodicity lemma.