Search results for "Heuristic"
showing 10 items of 476 documents
Multi-objective DSE algorithms' evaluations on processor optimization
2013
Very complex micro-architectures, like complex superscalar/SMT or multicore systems, have lots of configurations. Exploring this huge design space and trying to optimize multiple objectives, like performance, power consumption and hardware complexity is a real challenge. In this paper, using the multi-objective design space exploration tool FADSE, we tried to optimize the hardware parameters of the complex superscalar Grid ALU Processor. We compared how different heuristic algorithms handle the DSE optimization. Three of these algorithms are taken from the jMetal library (NSGAII, SPEA2 and SMPSO) while the other two, CNSGAII and MOHC were implemented by us. We show that in this huge design …
A distributed minimum losses optimal power flow for islanded microgrids
2017
Abstract In this work, the minimum losses optimal power dispatch problem for islanded microgrids with distributed energy resources (DER) is solved by means of a distributed heuristic approach. Optimal power management is performed almost in real time, with a predefined schedule, i.e. every 5 min, and the solution is applied to generators when the current operating solution violates voltage or current constraints or when the current configuration produces too large power losses. The operating point of both inverter-interfaced generation units as well as rotating production systems can be modified simply using local information. The latter are voltage measurements and power injections or load…
Economic lot scheduling on multiple production lines with resource constraints
2003
Abstract This paper deals with the multiple production line economic lot scheduling problem, where some items cannot be produced concurrently since they compete for some discrete resources. In particular, cyclic schedules are sought for a problem where identical production lines are present, lost sales are allowed, and minimization of the long-range production, setup, inventory, and shortage penalty costs are required. A heuristic procedure for this problem is introduced, a numerical example is worked out and some computational experiments are presented.
Justification technique generalizations
2006
The justification technique was introduced various decades ago for the resource-constrained project scheduling problem, although it has rarely been used with the problem. Justification is a simple and quick technique which when applied to schedules produces a new schedule that is, at most, as long as the original schedule — and often shorter. A recent article (Valls et al, 2005), showed that incorporating justification in heuristic algorithms can produce a substancial improvement in the results obtained. These results have motivated us to generalise this technique in order to study it in greater depth. This paper proposes distinct forms and generalisations for the justification technique an…
Queuing transitions in the asymmetric simple exclusion process
2003
Stochastic driven flow along a channel can be modeled by the asymmetric simple exclusion process. We confirm numerically the presence of a dynamic queuing phase transition at a nonzero obstruction strength, and establish its scaling properties. Below the transition, the traffic jam is macroscopic in the sense that the length of the queue scales linearly with system size. Above the transition, only a power-law shaped queue remains. Its density profile scales as $\delta \rho\sim x^{-\nu}$ with $\nu={1/3}$, and $x$ is the distance from the obstacle. We construct a heuristic argument, indicating that the exponent $\nu={1/3}$ is universal and independent of the dynamic exponent of the underlying…
An approximate/exact objective based search technique for solving general scheduling problems
2018
Abstract In this paper, we analyze single machine scheduling problems under the following minimization objectives: the maximum completion time (makespan), the total completion time and the maximum lateness, including fundamental practical aspects, which often occur in industrial or manufacturing reality: release dates, due dates, setup times, precedence constraints, deterioration (aging) of machines, as well as maintenance activities. To solve the problems, we propose an efficient representation of a solution and a fast neighborhood search technique, which calculates an approximation of criterion values in a constant time per solution in a neighborhood. On this basis, a novel approximate/ex…
HEURISTIC PROCEDURES FOR GROUP SCHEDULING
1989
ABSTRACT The group scheduling problem is investigated, solving numerous small and large sized examples with eight sequencing algorithms. A new approach, basically consisting in the definition of real machines' idles for each group, utilizing allowed shifting of non critical activities, is proposed. Moreover the CDS multi-shot algorithm is extended to group scheduling.
Dal quartetto alla jam session: strategie conversazionali e razionalità
2020
In questo articolo sosterrò che le nostre concezioni di linguaggio e comunicazione mutano in funzione dell’accezione di razionalità che viene assunta. In particolare, mostrerò come ad un modello di razionalità olimpica e assoluta – ovvero ad un modello di animale umano che ragiona seguendo le leggi della logica formale – corrisponda una concezione della comunicazione esemplificata dall’immagine del quartetto, un complesso musicale in cui quattro musicisti suonano insieme seguendo delle regole fisse e stabilite prima di iniziare a suonare. Questa immagine sembra ben rispecchiare i modelli di comunicazione proposti da Paul Grice e Jurgen Habermas,dominanti nello studio del linguaggio fino agl…
La representación sindical en España: cobertura y límites
2018
El objetivo de este artículo es realizar una aproximación al sistema de representación unitaria en la empresa en España a partir de una explotación estadística de los datos de las elecciones sindicales. Se trata de conocer aspectos como el alcance de la representación unitaria, la participación de los asalariados y la audiencia electoral de los sindicatos, con el objetivo de delimitar su representatividad y legitimidad. Nuestro trabajo se centra en el análisis de los tres últimos períodos electorales (2003-2007, 2007-2012 y 2012-2015), con objeto de evaluar el impacto del ciclo económico sobre la representación de los asalariados. The objective of this article is to make an approach to the …
Heuristics and Memory Strategies Used by Mathematicians
1996
The study of the cognitive processes involved in learning and acquisition of technically complex material is a main focus of interest for basic and applied research. Our research program tries to identh memory aids and heuristic training strategies useful for improving mathematics performance. Part of the effectiveness of a course, designed by taking into account knowledge about the cognitive system, has to do with the development of an adequate relationship with the belief system of the learner. As a first step in that direction, we present a survey of the opinions of a group of mathematicians about the dd€iculty of their subjecr matter, the strategies they use spontaneously to overcome di…