Hadas Shachnai

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We consider the problem of scheduling jobs that are given as <i>groups</i> of non-intersecting segments on the real line. Each job <i>J<inf>j</inf></i> is associated with an interval, <i>I<inf>j</inf>,</i> which consists of up to <i>t</i> segments, for some <i>t</i> &#8805; 1, a positive weight, <i>w<inf>j</inf>,</i> and two jobs are in conflict if any of(More)
The concept of submodularity plays a vital role in combinatorial optimization. In particular, many important optimization problems can be cast as submodular maximization problems, including maximum coverage, maximum facility location and max cut in directed/undirected graphs. In this paper we present the first known approximation algorithms for the problem(More)
The transactional approach to contention management guarantees atomicity by making sure that whenever two transactions have a conflict on a resource, only one of them proceeds. A major challenge in implementing this approach lies in guaranteeing progress, since transactions are often restarted.Inspired by the paradigm of <i>non-clairvoyant</i> job(More)
We consider a scheduling problem in which a bounded number of jobs can be processed simultaneously by a single machine. The input is a set of n jobs J = &#x007B;J<inf>1</inf>, &#x2026; , J<inf>n</inf>&#x007D;. Each job, J<inf>j</inf>, is associated with an interval [s<inf>j</inf>, c<inf>j</inf>] along which it should be processed. Also given is the(More)
<lb>We consider the following fundamental scheduling problem. The input consists of n jobs to be sched-<lb>uled on a set of machines of bounded capacities. Each job is associated with a release time, a due<lb>date, a processing time and demand for machine capacity. The goal is to schedule all of the jobs<lb>non-preemptively in their release-time-deadline(More)
We study two variants of the classic knapsack problem, in which we need to place items of <e5>different types</e5> in multiple knapsacks; each knapsack has a limited capacity, and a bound on the number of different types of items it can hold: in the <e5>class-constrained multiple knapsack problem (CMKP)</e5> we wish to maximize the total number of packed(More)
The <i>data migration</i> problem is to compute an efficient plan for moving data stored on devices in a network from one configuration to another. We consider this problem with the objective of minimizing the sum of completion times of all storage devices. It is modeled by a transfer graph, where vertices represent the storage devices, and the edges(More)
We consider the following scheduling with batching problem that has many applications, e.g., in multimedia-on-demand and manufacturing of integrated circuits. The input to the problem consists of <i>n</i> jobs and <i>k</i> parallel machines. Each job is associated with a set of time intervals in which it can be scheduled (given either explicitly or(More)