Results 1  10
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268
Giotto: A timetriggered language for embedded programming
 PROCEEDINGS OF THE IEEE
, 2001
"... Giotto provides an abstract programmer's model for the implementation of embedded control systems with hard realtime constraints. A typical control application consists of periodic software tasks together with a mode switching logic for enabling and disabling tasks. Giotto speci es timetrigger ..."
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Cited by 219 (33 self)
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Giotto provides an abstract programmer's model for the implementation of embedded control systems with hard realtime constraints. A typical control application consists of periodic software tasks together with a mode switching logic for enabling and disabling tasks. Giotto speci es timetriggered sensor readings, task invocations, and mode switches independent of any implementation platform. Giotto can be annotated with platform constraints such as tasktohost mappings, and task and communication schedules. The annotations are directives for the Giotto compiler, but they do not alter the functionality andtiming of a Giotto program. By separating the platformindependent from the platformdependent concerns, Giotto enables a great deal of exibility inchoosing control platforms as well as a great deal of automation in the validation and synthesis of control software. The timetriggered nature of Giotto achieves timing predictability, which makes Giotto particularly suitable for safetycritical applications.
MultiRobot Task Allocation: Analyzing the Complexity and Optimality of Key Architectures
 ICRA 2003
, 2003
"... Important theoretical aspects of multirobot coordination mechanisms have, to date, been largely ignored. To address part of this negligence, we focus on the problem of multirobot task allocation. We give a formal, domainindependent, statement of the problem and show it to be an instance of another ..."
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Cited by 76 (11 self)
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Important theoretical aspects of multirobot coordination mechanisms have, to date, been largely ignored. To address part of this negligence, we focus on the problem of multirobot task allocation. We give a formal, domainindependent, statement of the problem and show it to be an instance of another, wellstudied, optimization problem. In this light, we analyze several recently proposed approaches to multirobot task allocation, describing their fundamental characteristics in such a way that they can be objectively studied, compared, and evaluated.
Scheduling multiprocessor tasks  An overview
 EUROPEAN JOURNAL OF OPERATIONAL RESEARCH
, 1996
"... Multiprocessor tasks require more than one processor at the same moment of time. This relatively new concept in scheduling theory emerged with the advent of parallel computing systems. In this work we present the state of the art for multiprocessor task scheduling. We show the rationale behind the c ..."
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Cited by 38 (3 self)
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Multiprocessor tasks require more than one processor at the same moment of time. This relatively new concept in scheduling theory emerged with the advent of parallel computing systems. In this work we present the state of the art for multiprocessor task scheduling. We show the rationale behind the concept of multiprocessor tasks. The standard threefield notation is extended to accommodate multiprocessor tasks. The main part of the work is presentation of the results in multiprocessor tasks scheduling both for parallel and for dedicated processors.
Polynomial Time Algorithms for Minimizing the Weighted Number of Late Jobs on a Single Machine with Equal Processing Times
, 1998
"... We study the problem of minimizing the weighted number of late jobs to be scheduled on a single machine when processing times are equal. In this paper, we show that this problem, as well as its preemptive variant, are both strongly polynomial. When preemption is not allowed 1  pj = p, rj  Σ wj Uj, ..."
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Cited by 33 (3 self)
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We study the problem of minimizing the weighted number of late jobs to be scheduled on a single machine when processing times are equal. In this paper, we show that this problem, as well as its preemptive variant, are both strongly polynomial. When preemption is not allowed 1  pj = p, rj  Σ wj Uj, the problem can be solved in O(n 7). In the preemptive case, 1  pj = p, pmtn, rj  Σ wj Uj, the problem can be solved in O(n 10). Both algorithms are based upon dynamic programming.
Minimizing Flow Time Nonclairvoyantly
 In Proceedings of the 38th Symposium on Foundations of Computer Science
, 1997
"... We consider the problem of scheduling a collection of dynamically arriving jobs with unknown execution times so as to minimize the average response/flow time. This the classic CPU scheduling problem faced by timesharing operating systems. In the standard 3field scheduling notation this is the noncl ..."
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Cited by 31 (9 self)
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We consider the problem of scheduling a collection of dynamically arriving jobs with unknown execution times so as to minimize the average response/flow time. This the classic CPU scheduling problem faced by timesharing operating systems. In the standard 3field scheduling notation this is the nonclairvoyant version of 1 j pmtn; r j j P F j . Its easy to see that every algorithm that doesn't unnecessarily idle the processor is at worst ncompetitive, where n is the number of jobs. Yet there is no known nonclairvoyant algorithm, deterministic or randomized, with a competitive ratio provably o(n). In this paper with give a randomized nonclairvoyant algorithm, RMLF, that has competitive ratio \Theta(log n log log n) against an adaptive adversary. RMLF is a slight variation of the multilevel feedback (MLF) algorithm used by the Unix operating system, further justifying the adoption of this algorithm. Motwani, Phillips, and Torng [12] showed that every randomized nonclairvoyant algorithm...
Adaptive Communication Algorithms for Distributed Heterogeneous Systems
 PROCEEDINGS OF THE 7TH IEEE INTNL. SYMPOSIUM ON HIGH PERFORMANCE DISTRIBUTED COMPUTING (HPDC 1998)
, 1998
"... Heterogeneous networkbased systems are emerging as attractive computing platforms for HPC applications. This paper discusses fundamental research issues that must be addressed to enable networkaware communication at the application level. We present a uniform framework for developing adaptive comm ..."
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Cited by 27 (2 self)
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Heterogeneous networkbased systems are emerging as attractive computing platforms for HPC applications. This paper discusses fundamental research issues that must be addressed to enable networkaware communication at the application level. We present a uniform framework for developing adaptive communication schedules for various collective communication patterns. Schedules are developed at runtime, based on network performance information obtained from a directory service. We illustrate our framework by developing communication schedules for total exchange. Our first algorithm develops a schedule by computing a series of matchings in a bipartite graph. We also present a O(P³) heuristic algorithm, whose completion time is within twice the optimal. This algorithm is based on the open shop scheduling problem. Simulation results show performance improvements of a factor of 5 over well known homogeneous scheduling techniques.
A Scheduling Approach to Coalitional Manipulation
"... The coalitional manipulation problem is one of the central problems in computational social choice. In this paper we focus on solving the problem under the important family of positional scoring rules, in an approximate sense that was advocated by Zuckerman et al. [SODA 2008]. Our main result is a p ..."
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Cited by 26 (11 self)
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The coalitional manipulation problem is one of the central problems in computational social choice. In this paper we focus on solving the problem under the important family of positional scoring rules, in an approximate sense that was advocated by Zuckerman et al. [SODA 2008]. Our main result is a polynomialtime algorithm with (roughly speaking) the following theoretical guarantee: given a manipulable instance with m alternatives the algorithm finds a successful manipulation with at most m − 2 additional manipulators. Our technique is based on a reduction to the scheduling problem known as QpmtnCmax, along with a novel rounding procedure. We demonstrate that our analysis is tight by establishing a new type of integrality gap. We also resolve a known open question in computational social choice by showing that the coalitional manipulation problem remains (strongly) NPcomplete for positional scoring rules even when votes are unweighted. Finally, we discuss the implications of our results with respect to the question: “Is there a prominent voting rule that is usually hard to manipulate?”
Maximizing Job Completions Online
 In Proceedings of the Sixth European Symposium on Algorithms
, 1998
"... We consider the problem of maximizing the number of jobs completed by their deadline in an online single processor system where the jobs are preemptable and have release times. So in the standard three field scheduling notation, this is the online version of the problem 1 j r i ; pmtn j P (1 \Gamm ..."
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Cited by 24 (0 self)
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We consider the problem of maximizing the number of jobs completed by their deadline in an online single processor system where the jobs are preemptable and have release times. So in the standard three field scheduling notation, this is the online version of the problem 1 j r i ; pmtn j P (1 \Gamma U i ). We present a deterministic algorithm Lax, and show that for every instance I, it is the case that either Lax, or the wellknown deterministic algorithm SRPT (Shortest Remaining Processing Time), is constant competitive on I. An immediate consequence of this result is a constant competitive randomized algorithm for this problem. It is known that no constant competitive deterministic algorithm exists for this problem. This is the first time that this phenomenon, the randomized competitive ratio is constant in spite of the fact that the deterministic competitive ratio is nonconstant, has been demonstrated to occur in a natural online problem. This result is also a first step toward det...
A Logical Framework for Scheduling Workflows Under Resource Allocation Constraints
 In VLDB
, 2002
"... A workflow consists of a collection of coordinated tasks designed to carry out a welldefined complex process, such as catalog ordering, trip planning, or a business process in an enterprise. Scheduling of workflows is a problem of finding a correct execution sequence for the workflow tasks, i. ..."
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Cited by 23 (4 self)
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A workflow consists of a collection of coordinated tasks designed to carry out a welldefined complex process, such as catalog ordering, trip planning, or a business process in an enterprise. Scheduling of workflows is a problem of finding a correct execution sequence for the workflow tasks, i.e., execution that obeys the constraints that embody the business logic of the workflow. Research on workflow scheduling has largely concentrated on temporal constraints, which specify correct ordering of tasks. Another important class of constraints  those that arise from resource allocation  has received relatively little attention in workflow modeling. Since typically resources are not limitless and cannot be shared, scheduling of a workflow execution involves decisions as to which resources to use and when. In this work, we present a framework for workflows whose correctness is given by a set of resource allocation constraints and develop techniques for scheduling such systems. Our framework integrates Concurrent Transaction Logic (CTR) with constraint logic programming (CLP), yielding a new logical formalism, which we call Concurrent Constraint Transaction Logic, or CCTR.
Ant Colony Optimization for FOP Shop Scheduling: A case study on different pheromone representations
 In Proceedings of the 2002 Congress on Evolutionary Computing (CEC'02
, 2002
"... In this work we deal with the FOP Shop scheduling problem which is a general scheduling problem including Job Shop scheduling, Open Shop scheduling and Mixed Shop scheduling as special cases. The aim of this paper is to compare different pheromone representations taken from the literature with our n ..."
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Cited by 23 (5 self)
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In this work we deal with the FOP Shop scheduling problem which is a general scheduling problem including Job Shop scheduling, Open Shop scheduling and Mixed Shop scheduling as special cases. The aim of this paper is to compare different pheromone representations taken from the literature with our new approach. The pheromone representations are used by an Ant Colony Optimization algorithm to construct solutions to the FOP Shop scheduling problem.