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- Göthe-Lundgren, Maud, et al.
(författare)
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An optimization model for refinery production scheduling
- 2002
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Ingår i: International Journal of Production Economics. - Amsterdam, Netherlands : Elsevier. - 0925-5273 .- 1873-7579. ; 78:3, s. 255-270
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we describe a production planning and scheduling problem in an oil refinery company. The problem concerns the planning and the utilization of a production process consisting of one distillation unit and two hydro-treatment units. In the process crude oil is transformed to bitumen and naphthenic special oils. The aim of the scheduling is to decide which mode of operation to use in each processing unit at each point in time, in order to satisfy the demand while minimizing the production cost and taking storage capacities into account. The production cost includes costs for changing mode and for holding inventory. We formulate a mixed integer linear programming model for the scheduling problem. The model can be regarded as a generalized lot-sizing problem, where inventory capacities are considered and more than one product is obtained for some modes of operation. A number of modifications and extensions of the model are also discussed. It is shown how the optimization model can be used as a viable tool for supporting production planning and scheduling at the refinery, and that it is possible to analyze scheduling scenarios of realistic sizes. It is also shown that the model can support shipment planning and strategic decisions concerning new products and investments in storage capacity. © 2002 Elsevier Science B.V. All rights reserved.
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- Persson, Jan, 1972-, et al.
(författare)
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A Tabu Search Heuristic for Scheduling the Production Processes at an Oil Refinery
- 2004
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Ingår i: International Journal of Production Research. - : Taylor & Francis. - 0020-7543 .- 1366-588X. ; 42:3, s. 445-471
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we present a tabu search heuristic which can be used for scheduling the production at an oil refinery. The scheduling problem is to decide which production modes to use at the different processing units at each point in time. The problem is a type of lot-sizing problem where costs of changeovers, inventories and production are considered. In the suggested tabu search heuristic we explore the use of variable neighbourhood, dynamic penalty and different tabu lists. Computational results are presented for different versions of the heuristic and the results are compared to the best-known lower bound for a set of scheduling scenarios.
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- Andersson, Per Magnus, et al.
(författare)
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Balanced Scorecard i landsting - erfarenheter från tolv projekt i Region Skåne
- 2000
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Denna rapport sammanfattar och reflekterar över lärdomar från tolv Balanced Scorecard projekt. Rapporten skall i första hand läsas som ett bidrag till diskussionen om relevansen av Balanced Scorecard i utvecklingen av kommunala sektorns styrsystem. Vad som förmedlas är en illustration av och reflektion över styrmodellens förtjänster och till¬korta¬kommanden. Rapporten är ett resultat av ett utvecklingsprogram för Region Skånes ekonomer under åren 1998-1999. Under programmens löptid fick 48 ekonomer arbeta med att sälja in, förankra och igångsätta ett utvecklingsarbete med fokus på Balanced Scorecard i 12 enheter inom Region Skåne. Genomförda projektarbeten doku¬menterades i tolv projekt¬rapporter, som i redigerat och förkortat skick bildar stommen i denna rapport. Med tanke på att det finns få dokumenterade beskrivningar av hur man de facto kan arbeta med BSC inom den kommunala sektorn är förhoppningen att rapporten kan vara till glädje för de som är nyfikna på BSC. Rapporten innehåller också diskussioner kring relationen mellan BSC och övriga styrsystem.
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- Andersson, Per Magnus, et al.
(författare)
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Balanced Scorecards förtjänstfulla töjbarhet
- 2000
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Ingår i: Kommunal ekonomi. - 0282-0099. ; :2000:5, s. 30-31
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Artikeln beskriver och analyserar alternativa sätt att använda sig av Balancerat styrkort inom en rad olika verksamheter inom hälso och sjukvård.
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- Barabash, Stas, et al.
(författare)
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Towards low-cost Swedish planetary missions
- 2004
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- As a continuation of the Swedish tradition of designing small and high-quality spacecrafts such as Freja, Astrid, Munin, and SMART-1, Swedish scientists and engineers have proposed aggressive but feasible missions as the next national-level target: (1) an interplanetary plasma module (or subsatellite) Saga, and (2) a technology mission Prisma. The Saga micro-satellite contains a separation mechanism, technologically-challenging communication package, and plasma payload with an estimated total mass of 37kg to make the mission possible with a piggy-back launch or by attaching to another planetary mission. The Prisma mission consists of a semi-coordinated dual micro- and nano-satellites flying together in Earth orbit with state-of-art instruments to test. Both projects aim to develop and test new key spacecraft technologies.
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- Cuttini, M, et al.
(författare)
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End-of-life decisions in neonatal intensive care : physicians' selfreported practices in seven European countries
- 2000
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Ingår i: The Lancet. - London. - 0140-6736 .- 1474-547X. ; 355:9221, s. 2112-2118
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundThe ethical issue of foregoing life-sustaining treatment for newborn infants at high risk of death or severe disability is extensively debated, but there is little information on how physicians in different countries actually confront this issue to reach end-of-life decisions. The EURONIC project aimed to investigate practices as reported by physicians themselves.MethodsThe study recruited a large, representative sample of 122 neonatal intensive-care units (NICUs) by census (in Luxembourg, the Netherlands, and Sweden) or stratified random sampling (in France, Germany, the UK, Italy, and Spain) with an overall response rate of 86%. Physicians' practices of end-of-life decision-making were investigated through an anonymous, self-administered questionnaire. 1235 completed questionnaires were returned (response rate 89%).FindingsIn all countries, most physicians reported having been involved at least once in setting limits to intensive care because of incurable conditions (61–96%); smaller proportions reported such involvement because of a baby's poor neurological prognosis (46–90%). Practices such as continuation of current treatment without intensification and withholding of emergency manoeuvres were widespread, but withdrawal of mechanical ventilation was reported by variable proportions (28–90%). Only in France (73%) and the Netherlands (47%) was the administration of drugs with the aim of ending life reported with substantial frequency. Age, length of professional experience, and the importance of religion in the physician's life affected the likelihood of reporting of non-treatment decisions.InterpretationA vast majority of neonatologists in European NICUs have been involved in end-of-life limitation of treatments, but type of decision-making varies among countries. Cultur-related and other country-specific factors are more relevant than characteristics of individual physicians or units in explaining such variability.
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- Cuttini, M., et al.
(författare)
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Should euthanasia be legal? An international survey of neonatal intensive care units staff
- 2004
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Ingår i: Archives of Disease in Childhood. - 0003-9888 .- 1468-2044. ; 89:1
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To present the views of a representative sample of neonatal doctors and nurses in 10 European countries on the moral acceptability of active euthanasia and its legal regulation. Design: A total of 142 neonatal intensive care units were recruited by census (in the Netherlands, Sweden, Hungary, and the Baltic countries) or random sampling (in France, Germany, Italy, Spain, and the United Kingdom), 1391 doctors and 3410 nurses completed an anonymous questionnaire (response rates 89% and 86% respectively). Main outcome measure: The staff opinion that the law in their country should be changed to allow active euthanasia "more than now". Results: Active euthanasia appeared to be both acceptable and practiced in the Netherlands, France, and to a lesser extent Lithuania, and less acceptable in Sweden, Hungary, Italy, and Spain. More then half (53%) of the doctors in the Netherlands, but only a quarter (24%) in France felt that the law should be changed to allow active euthanasia "more than now". For 40% of French doctors, end of life issues should not be regulated by law. Being male, regular involvement in research, less than six years professional experience, and having ever participated in a decision of active euthanasia were positively associated with an opinion favouring relaxation of legal constraints. Having had children, religiousness, and believing in the absolute value of human life showed a negative association. Nurses were slightly more likely to consider active euthanasia acceptable in selected circumstances, and to feel that the law should be changed to allow it more than now. Conclusions: Opinions of health professionals vary widely between countries, and, even where neonatal euthanasia is already practiced, do not uniformly support its legalisation.
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