| 1. |
- Aardal, Karen, et al.
(författare)
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Decomposition principles applied to the dynamic production and work-force scheduling problem
- 1987
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Ingår i: Engineering Costs and Production Economics. - 0167-188X .- 1878-4011. ; 12:1-4, s. 39-49
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Tidskriftsartikel (refereegranskat)abstract
- One of the most important problems in the production and inventory planning field, is the scheduling of production and work force in a dynamic environment. Although this problem can be formulated as a linear program, it is often quite difficult to solve directly, due to its large scale. Instead, it might be fruitful to use a decomposition approach. Decomposition, in general, means decomposing a difficult problem into several easier, or a sequence of easier problems which are later coordinated to reconstruct the original problem.In this report we discuss several possibilities of applying the most common decomposition principles, namely Benders (primal) and Datnzig-Wolfe (dual), as well as a relatively new decomposition method, called cross decomposition, to the dynamic, multiproduct production and employment planning problem. A number of special cases are also presented.
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| 2. |
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| 3. |
- Aberg, B, et al.
(författare)
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Delayed left ventricular free wall rupture complicating coronary artery bypass surgery. A case report.
- 1985
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Ingår i: Scandinavian journal of thoracic and cardiovascular surgery. - : Informa UK Limited. - 0036-5580. ; 19:3, s. 273-7
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Tidskriftsartikel (refereegranskat)abstract
- Rupture of the left ventricular free wall is a not uncommon life-threatening complication of acute myocardial infarction and after prosthetic mitral valve replacement. To our knowledge, no case of left ventricular rupture after coronary artery bypass surgery has been reported. A case is now described in which coronary artery bypass grafting was complicated by delayed rupture, which was successfully repaired. Different etiologic factors are discussed, but the cause considered most likely was trauma from elevation of and traction on the heart in exposure of its posterior aspect.
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| 4. |
- Aberg, T, et al.
(författare)
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Cerebral function monitoring in rats with a critical hepatic injury treated with pneumatic antishock garment and infusion
- 1989
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Ingår i: Journal of Trauma. - 0022-5282. ; 29:2, s. 168-174
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Tidskriftsartikel (refereegranskat)abstract
- Twenty-nine rats were subjected to a severe standardized hepatic injury and divided into four groups. In addition to controls, the animals were treated with PASG inflated to 40 mm Hg, PASG and infusion of Ringer's acetate, or PASG and infusion of Ringer's acetate and Dextran 70 in combination. The aim of the infusion therapy was to stabilize the mean aortic blood pressure at 60 mm Hg. PASG significantly prolonged the survival time and the time during which a sensory evoked response could be observed. The PASG also prolonged the time before the EEG amplitude began to decrease or a burst-suppression pattern appeared in the EEG. Intravenous infusion of Ringer's acetate did not prolong these times compared to when PASG was used alone; when Dextran 70 was added to the infusion therapy these times were reduced. Changes in the EEG were recorded at a mean aortic pressure of 60 mm Hg when infusions were given, whereas the aortic pressure had to fall to 40 mm Hg before any changes could be observed when no infusions were used.
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| 5. |
- Abeysekera, John D.A., et al.
(författare)
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A head-model reconstruction based upon photogrammetric data from Sri Lankan adult males relevant to the design of headgear
- 1989
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Ingår i: Journal of Human Ergology. - 0300-8134. ; 18:2, s. 199-211
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Tidskriftsartikel (refereegranskat)abstract
- Due to the large variability in heads and faces in one population, the standard anthropometric dimensions of the head, measured from anatomical landmarks alone, may not suffice for the design of fitting headgear, e.g., helmets. To provide adequate data of the shapes and contours of the head to the designer, appropriate head models sculptured using comprehensive head dimensions, must be developed. This paper describes (a) a procedure of collecting comprehensive anthropometric data of the head using a photogrammetric method and (b) a simple sculpturing technique to reconstruct a head model of the user population
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| 6. |
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| 7. |
- Abeysekera, John D.A., et al.
(författare)
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Body size variability between people in developed and developing countries and its impact on the use of imported goods
- 1989
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Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 0169-8141 .- 1872-8219. ; 4:2, s. 139-149
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Tidskriftsartikel (refereegranskat)abstract
- The Industrially Developing Countries (IDC) today, to a great extent, depend on Industrialized Countries (IC) for the supply of most industrial goods. An attempt has been made to ascertain the degree of design incompatibility experienced by users of these imported goods due to differences in the body sizes of people in producer and user countries. A comparative study of variations in body sizes is made from data available in literature and from anthropometric surveys. The results reveal differences in almost every part of the human body. The need for reliable anthropometric data in respect of IDC is stressed. Urgent measures are required to introduce changes in equipment, particularly for the benefit of users in IDC.
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| 8. |
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| 9. |
- Abeysekera, John D.A., et al.
(författare)
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Ergonomics assessment of selected dust respirators : their use in the tropics
- 1987
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Ingår i: Applied Ergonomics. - : Elsevier BV. - 0003-6870 .- 1872-9126. ; 18:4, s. 266-272
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Tidskriftsartikel (refereegranskat)abstract
- The suitability and effectiveness of four different types of British made respirators were studied with respect to comfort, convenience and fit on wearers in Sri Lanka (a developing country). Objective and subjective assessments were made to evaluate the degree of discomfort and interferences to the use of senses. The study revealed that factors such as breathing resistance, work-rate and activity period affected the physiological responses. The weight of the respirator and the skin temperature had no direct relationship with the cardiovascular stress. Positive-pressure respirators that gave lower face temperatures than negative-pressure masks gave this type of respirator an additional advantage in hot environments. Respirators that restricted jaw movement affected the speech intelligibility of the wearer. Orinasal masks restricted vision more than the other types. The problem of fit was found negligible though head and face dimensions significantly differed between the British and the Sri Lankans. Subjective assessment correlated well with objective tests.
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| 10. |
- Abeysekera, John D.A., et al.
(författare)
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Ergonomics evaluation of modified industrial helmets for use in tropical environments
- 1988
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Ingår i: Ergonomics. - : Informa UK Limited. - 0014-0139 .- 1366-5847. ; 31:9, s. 1317-1329
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Tidskriftsartikel (refereegranskat)abstract
- Hotness, weight, fitting problems etc., have been found to be the chief causes of the unpopularity of industrial safety helmets in tropical environments in developing countries (DC). Some selected safety helmets manufactured in industrialized countries (IC) were modified to provide extra head ventilation and to reduce weight, in order to make them more acceptable to users in hot environments. The modified helmets were subjected to ergonomics evaluation both objectively and subjectively in the laboratory (in simulated tropical conditions) as well as in the field situation. There was evidence that white helmets had some advantages in comfort, viz. reduction of hotness, compared to the other colours, e.g. red, green etc., when worn in the presence of radiant heat in the laboratory. Ventilation holes provided at the top of the shell seemed to reduce the greenhouse effect within the helmet shell which therefore felt less uncomfortable than a fully covered helmet. Even with a small reduction of weight, such as 45 g in helmets weighing about 350g, the difference in weight was perceived by the wearers. In adapting helmets made in IC for use in tropical climates, head ventilation and low weight perception are important aspects in comfort which need to be considered. In addition to low cost, a harness material suitable for sweat absorption is required. Adjustability and sizing to fit 90% of the user population also needs to be considered in the design and manufacture of safety helmets for people in DC.
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