Simple and practical optimization approach based to solve a truck load and delivery problem at long haul distances with heterogenous products

This paper proposes an optimization based approach for solving the logistic processes of deliveries scheduling and product accommodation during loading with a heterogeneous fleet of vehicles. The approach focuses on the case of products with “low density values” and high heterogeneous volume and weight, and with traveling large distances to different zones, in which transportation costs constitute a important proportion of total logistic costs. The proposed approach consists of a two-phase strategy: The first uses a “Cutting Stock Problem” formulation to define utilization areas inside trucks assigned to each product family. This task is achieved by minimizing the long-haul transportation costs as a function of the vehicle size, considering a set of predefined solutions for feasible and efficient loading obtained as a result of the accumulated experience. The second phase consists of Bin Packing Problem version with a known number of bins, which were previously determined in the first phase of the approach. In this phase, different orders from a set of customers are assigned to each truck by obeying the predefined utilization areas per product category obtained in the first phase while minimizing the number of visits of each truck. The results show that the model addresses the analyzed problem in an efficient manner, which is reflected in reasonable resolution times and costs from a practical implementation perspective. Additionally, it is observed that long-haul delivery costs and vehicle utilization tend to improve with the increase of the utilized number of patterns even when the execution time is incremented.MaestríaMagister en Ingeniería Civi

An extension of Lehman's theorem and ideal set functions

Lehman’s theorem on the structure of minimally nonideal clutters is a fundamental result in polyhedral combinatorics. One approach to extending it has been to give a common generalization with the characterization of minimally imperfect clutters (Sebő, 1998; Gasparyan et al., 2003). We give a new generalization of this kind, which combines two types of covering inequalities and works well with the natural definition of minors. We also show how to extend the notion of idealness to unit-increasing set functions, in a way that is compatible with minors and blocking operations

Escalonamento de visitas domiciliárias de um centro de saúde

A saúde é um dos poderosos fatores de integração e coesão social, mas também de geração de riqueza e bem-estar. Nas sociedades desenvolvidas, o envelhecimento da população constitui uma evidência. Portugal, assim como outros países da Europa, tem vindo a registar nas últimas décadas profundas transformações demográficas caracterizadas, entre outros aspetos, pelo aumento da longevidade e da população idosa e pela redução da natalidade e população jovem. Assim, os cuidados de saúde domiciliários são cuidados prestados de forma continuada, orientados para a resolução dos problemas de saúde das pessoas e cuja complexidade não requer a sua institucionalização mas que, pela sua situação de dependência global, transitória ou crónica, as impede de se deslocarem aos Centros de Saúde, distinguindo-se este conceito por hospitalização domiciliária. Os cuidados de saúde domiciliários concretizamse através de Visitas Domiciliárias, cuja periodicidade das visitas programadas varia em função das necessidades de cuidados do doente e deverá ser estabelecida, consensualmente na e em equipa, onde necessariamente se inclui o doente, o cuidador e/ou família, com base nos resultados que se pretende atingir. Normalmente, as visitas são planeadas de forma manual e sem apoio computacional. Desta forma, torna-se imprescindível, para as Unidades de Saúde que desempenham serviços de cuidados ao domicílio, otimizar os planeamentos relacionados. Assim, surge o problema de planeamento de rotas para veículos (Vehicle Routing Problem, VRP), um problema complexo de otimização combinatória bem conhecido, cujo objetivo é encontrar a rota mais curta. Neste caso, para as equipas de profissionais de saúde, realizam procedimentos médicos para pacientes doentes, na qual administram medicamentos e vários tipos de tratamentos. Neste trabalho, pretende-se realizar o planeamento automático das visitas domiciliárias, de uma Unidade de Saúde de Bragança, com o objetivo de minimizar o tempo total despendido pelos enfermeiros e, desta forma, reduzir os custos envolvidos. Também se pretende, com este trabalho verificar qual a metodologia mais eficaz para realizar as visitas domiciliárias, comparando os resultados obtidos pela metodologia que irá ser abordada com um algoritmo de programação inteira, com os resultados obtidos pela metodologia já estudada em literatura, o Algoritmo Genético. A metodologia desenvolvida foi testada no CPLEX, que permitiu resolver o problema de forma eficiente e breve em tempo de resolução, obtendo as respetivas soluções de planeamento das visitas domiciliárias para os dados apresentados. Em todos os horários das visitas domiciliárias a realizar pelos enfermeiros, verificou-se uma redução significativa do tempo gasto pelos enfermeiros, assim como, no tempo de espera dos pacientes.Health is one of the powerful factors of social integration and cohesion, but also of wealth and well-being. In developed societies, the aging of the population is evidence. Portugal, as well as other European countries, has undergone deep demographic changes in recent decades, characterized by, among other aspects, the increase in longevity and the elderly population, the reduction of the birth rate and the young population. Therefore, home health care is a continuous of care directed at solving people’s health problems and whose complexity does not require institutionalization but which, because of their global, transitory or chronic dependence, prevents them from to the Health Centers, distinguishing this concept by home hospitalization. Home health care is carried out through Home Visits, whose periodicity of scheduled visits varies according to the patient’s care needs and should be established, consensually in and in a team, where necessarily includes the patient, caregiver and/or family, based on the results to be achieved. Usually visits are planned manually and without computer support. In this way, it is essential for the Health Units that perform home care services to optimize related planning. Thus, arises the Vehicle Routing Problem (VRP), a well-known complex combinatorial optimization problem, which aims to find the shortest route. In this case, for teams of healthcare professionals, they perform medical procedures for sick patients who administer medications and various types of use. In this study, we intend to carry out the automatic planning of home visits, from a Bragança Health Unit, with the aim of minimizing the total time spent by nurses and, in this way, reducing the costs involved. It is also intended, with this work, to verify which is the most effective methodology to make home visits, comparing the results obtained by the methodology that will be approached with an entire programming algorithm, with the results of the methodology already studied in the literature, or in the genetic algorithm. The developed methodology was tested in the CPLEX, which allowed to solve the problem in an efficient and brief way in resolution time, obtaining the respective solutions of home visits planning for the presented data. At all times of home visits by nurses, there was a significant reduction in the time spent by nurses, as well as in patients’ waiting time