Assigning Classes To Teachers In Universities Via Mathematical Modelling: Using Beam Search Method And Simulation In Java

In universities, before the beginning of each school year, it is held the distribution of classes among the available teachers. For such task, different constraints must be fulfilled like preventing a teacher to teach in two different places at the same time and avoid solutions in which some teachers have more class hours than others. This process, if performed manually, is time consuming and does not allow viewing other combinations of assignment of classes to teachers. In addition, it is subject to error. This study aims to develop a decision support tool for the problem of assigning teachers to classes in universities. The project includes the development of a computer program using the concepts of object orientation as a way to implement a search algorithm called Beam Search which explores the combinatorial nature of the problem. The programming language used is Java and the program has a graphical interface for insertion and manipulation of the relevant data. © 2013 DIME UNIVERSITÀ DI GENOVA.577586Al-Yakoob, S.M., Sherali, H.D., A column generation mathematical programming approach for a classfaculty assignment problem with preferences (2013) Computational Management Science, pp. 1-22. , to appear inAl-Yakoob, S.M., Sherali, H.D., Al-Jazzaf, M., A mixed-integer mathematical modeling approach to exam timetabling (2010) Computational Management Science, 7 (1), pp. 19-46Azevedo, A.T., Ribeiro, C.M., Sena, G.J.D., Chaves, A.A., Neto, L.L.S., Moretti, A.C., Solving the 3D container ship loading planning problem by representation by rules and beam search (2012) ICORES, pp. 132-141Deitel, H.M., Deitel, P.J., (2006) Java: How to Programm, , 6. ed. BookmanDella Croce, F., T'kindt, V., A recovering beam search algorithm for the one-machine dynamic total completion time scheduling problem (2002) Journal of the Operational Research Society, 54, pp. 1275-1280Gunawan, A., Ng, K.M., Poh, K.L., Solving the teacher assignment-course scheduling problem by a hybrid algorithm Cite Seer, , http://130.203.133.150/viewdoc/download?doi=10.1.1.193.3646&rep= rep1&type=pdf, Available in: Access: 21 jun. 2013Sun Microsystems, Platform, , http://java.sun.com/javase/6/docs/api/, Standard Edition 6 API Specification. Available in: . Access: 20 jan. 2012Michael, W.C., Laporte, G., Recent developments in practical course timetabling (1998) Selected Papers from the Second International Conference on Practice and Theory of Automated Timetabling II, pp. 3-19. , Springer- Verlag, London, UKSabuncuoglu, I., Bayiz, M., Job shop scheduling with beam search (1999) European Journal of Operational Research, 118, pp. 390-412Ow, P.S., Morton, T.E., Filtered beam search in scheduling (1988) International Journal of Production Research, 26, pp. 35-62Ribeiro, C.M., Azevedo, A.T., Teixeira, R.F., Problem of assignment cells to switches in a cellular mobile network via beam search method (2009) WSEAS Transactions on Communications, 9 (1), pp. 11-21Schaerf, A., (1999) A Survey of Automated Timetabling, , http://www.diegm.uniud.it/satt/papers/Scha99.pdf, Dipartimento di Informatica e Sistemistica, Università di Roma "La Sapienza", Available in: Access: 16 jun. 2011Valente, J.M.S., Alves, R.A.F.S., Filtered and recovering beam search algorithm for the early/tardy scheduling problem with no idle time (2005) Computers & Industrial Engineering, 48, pp. 363-375Willenmen, R.J., School timetable construction: Algorithms and complexity (2002) Technische Universiteit Eindhoven, , http://alexandria.tue.nl/extra2/200211248.pdf, Available in: Access: 10 jul.201

CONGELABILIDADE DO SÊMEN SUÍNO DE ACORDO COM O PERÍODO DE EQUILÍBRIO PRÉ-CONGELAMENTO E DA SENSIBILIDADE AO RESFRIAMENTO

O objetivo deste estudo foi avaliar a influência do período de equilíbrio pré-congelamento e da sensibilidade ao resfriamento sobre a qualidade do sêmen suíno congelado. Foram utilizados dez ejaculados de cada um dos 8 machos doadores. A motilidade de doses de sêmen preparadas a partir dos mesmos ejaculados utilizados no congelamento, foi avaliada simultaneamente, durante o resfriamento a 15ºC, a cada 24h. A porção de cada ejaculado destinada ao congelamento foi separada em duas partes que foram submetidas a equilíbrio prévio, a 20ºC, curto (1,5h) ou longo (20h). As palhetas foram descongeladas a 37ºC por 20 segundos e seu conteúdo (0,5mL) foi diluído (1:6) em Beltsville Thawing Solution (BTS). Foram avaliados a motilidade (MOT), acrossomos normais após o descongelamento (NARPD) e após o teste de termoresistência (NARTTR), e membranas íntegras (MI). Para a análise estatística, os ejaculados foram separados, de acordo com sua sensibilidade ao resfriamento, em dois grupos: motilidade 0,05). O equilíbrio por 20h não apresentou diferenças na MOT e MI (P>0,05), mas o NARPD e NARTTR foram superiores (

Thermal and digestive constraints to foraging behaviour in marine mammals

While foraging models of terrestrial mammals are concerned primarily with optimizing time/energy budgets, models of foraging behaviour in marine mammals have been primarily concerned with physiological constraints. This has historically centred on calculations of aerobic dive limits. However, other physiological limits are key to forming foraging behaviour, including digestive limitations to food intake and thermoregulation. The ability of an animal to consume sufficient prey to meet its energy requirements is partly determined by its ability to acquire prey (limited by available foraging time, diving capabilities and thermoregulatory costs) and process that prey (limited by maximum digestion capacity and the time devoted to digestion). Failure to consume sufficient prey will have feedback effects on foraging, thermoregulation and digestive capacity through several interacting avenues. Energy deficits will be met through catabolism of tissues, principally the hypodermal lipid layer. Depletion of this blubber layer can affect both buoyancy and gait, increasing the costs and decreasing the efficiency of subsequent foraging attempts. Depletion of the insulative blubber layer may also increase thermoregulatory costs, which will decrease the foraging abilities through higher metabolic overheads. Thus, an energy deficit may lead to a downward spiral of increased tissue catabolism to pay for increased energy costs. Conversely, the heat generated through digestion and foraging activity may help to offset thermoregulatory costs. Finally, the circulatory demands of diving, thermoregulation and digestion may be mutually incompatible. This may force animals to alter time budgets to balance these exclusive demands. Analysis of these interacting processes will lead to a greater understanding of the physiological constraints within which the foraging behaviour must operate