Occupational health and safety in construction projects: a case study on chemical industry sector

Background: This study was conducted to demonstrate the importance of occupational health and safety (OHS) management in construction project environments, taking into account the successful development of those projects. The associated problems in OHS management projects were also studied, as substantial empirical research has shown this is a complex theme with a large number of associated factors. Methods: In this study, three projects developed in the Portuguese petrochemical industry were analyzed using documentary analysis, ongoing interaction with workers and direct observations of work activity. A systematic literature review was also carried out. Results: Strengths and weaknesses related to OHS management of the three analyzed projects were identified. Grounded on the case studies results, a proposal of OHS management in construction projects, in a recommendations format, is also presented. Conclusion: Good results from OHS management in projects can be obtained as long as it is focused on success factors such as top management commitment, line responsibility, involvement of all employees, and, mainly, of direct and indirect managers. Well-defined OHS responsibilities, a well-sized and structured organization and the creation of an honest, healthy, motivating and useful OHS environment team with a competent and dynamic coordinator leader are also important success factors.info:eu-repo/semantics/publishedVersio

Integrated urban freight logistics combining passenger and freight flows - Mathematical model proposal

The aim of this research is to propose an urban logistics distribution service which benefits from the already installed passenger transport network. This service is based upon the concept of integration of the existing passenger transport network with the urban freight process. The aim is to reduce the number of fossil combustion powered commercial vehicles traveling within city boundaries, solely for goods transportation, thus contributing to reduce negative effects of urban logistics activities, namely pollution, noise, traffic congestion and accidents. Also, integrating goods and passenger flows will promote higher efficiency rates for the passenger transport network and enhance living conditions within major urban centers. A mathematical model for the operational planning of the proposed urban logistics distribution service is proposed. This model consists of assigning origins loads (or requests) to inbound hubs (bus operator centers), transferring the inbound hubs loads to a bus service, and transferring the bus loads to bus stops, to be collected by micro-logistics operators operating environmentally friendly vehicle fleets. The objective is to minimize the total service time while assuring services synchronization along the network and balancing the loads with the system capacities.(undefined

PDCA Protocol to ensure a Data-Driven Approach for Problem-Solving

Problem-solving based, as much as possible, on real data, expert knowledge, and on-field observation are quite desired objectives. However, it creates several difficulties on deployment in real situations. In this work, a data-driven version of the well-known PDCA cycle is proposed for continuous improvement within a general class of problems represented by key performance indicators (KPI). Such class is wide enough to accommodate several real problems but still has a controlled level of complexity that allows defining a general data-driven protocol that covers all the (sub)steps of the cycle. New approaches and alternatives in the literature are discussed. A brief example of one of the steps of the protocol is given with real data from a company that adopts many of the new Industry 4.0 technologies.publishe

Determinant factors for the strategic management of the supply chain of the angolan cement industry

Purpose: Cement is a priority consumer good in all modern societies. Considerable portions of the countries’ income are invested in construction and reconstruction of houses, shopping centers, schools, universities, research centers, pavements, bridges, dams, among other infrastructures. In view of its importance, it becomes relevant to understand the determinant factors for the strategic management of the cement supply chain (SC). The knowledge of these factors can support the development of management strategies that adequately orientate the operation of the cement industry and ensure an agile and/or efficient structure that facilitates the distribution of the products from this industrial sector. Methodology: This article presents the results of a qualitative research, based on semi-systematic literature review and interviews, which aimed to identify the determinant factors and barriers in the management of the SC of the Angolan cement industry (CI). Findings: This research made it possible to conclude that the determining factors are: cement production capacity and quality; supply levels and channels; infrastructure capacity and quality; capacity and quality of transport modes; existence of cement distribution strategies; collaboration, integration, agility, effectiveness and efficiency in the SC; availability of qualified labor; geographic location of markets; competitiveness factors (price, quality, response time, flexibility, agility, services, reliability, process variability and differentiation). Some barriers that undermine the supply of cement in the Angolan market have also been identified. Originality/value: Based on the literature review and the analysis of the interviews, we found that, in general, the strategic management of the SC of the CI depends on the level of development of the infrastructures, logistics, communication and the degree of collaboration and integration between the entitiesPeer Reviewe

Modelos e métodos para problemas de dimensionamento de lotes e escalonamento

Tese de doutoramento em Engenharia Industrial e de SistemasO trabalho que se apresenta nesta tese relaciona-se com o desenvolvimento de modelos e de métodos para a resolução de dois problemas de planeamento da produção de médio/curto prazo. A principal motivação consiste na exploração e comparação de diferentes abordagens, baseadas em programação inteira mista, em modelos/métodos de decomposição e em métodos heurísticos, para os problemas em estudo. O primeiro problema, é um problema clássico de dimensionamento de lotes, que está associado às decisões de planeamento da produção de médio-prazo. O problema consiste na determinação de um plano de produção para vários produtos finais ao longo de um determinado horizonte temporal, que minimize todos os custos envolvidos e respeite restrições de procura e de capacidade. Para este problema desenvolve-se um novo modelo exacto, que resulta da aplicação dos princípios da decomposição de Dantzig-Wolfe múltipla a uma formulação de programação inteira mista para o problema. Os princípios gerais de aplicação desta decomposição são também apresentados neste trabalho. A potencial mais valia deste modelo relaciona-se com a obtenção de limites inferiores de boa qualidade. O modelo que resulta da decomposição de Dantzig-Wolfe múltipla é comparado com dois modelos de decomposição alternativos, que se obtêm aplicando directamente os princípios da decomposição de Dantzig-Wolfe, e com o modelo de programação inteira mista, resolvido directamente através de um software de estado-da-arte. Para determinar a solução óptima inteira dos modelos de decomposição aplica-se o método de partição e geração de colunas (branchand- price). São apresentados resultados computacionais partindo de um conjunto de instâncias da literatura, para os vários modelos e métodos. O segundo problema estudado neste trabalho surge associado ao planeamento de curto-prazo e combina as decisões de dimensionamento de lotes, com as decisões de afectação e escalonamento desses lotes. Este estudo foi motivado por um problema real da indústria têxtil, no qual se pretende definir um plano de produção para uma secção de tricotagem, onde os principais componentes dos produtos finais são realizados num conjunto de máquinas paralelas idênticas. Para este problema propõe-se um novo modelo de programação inteira mista, que se resolve através de um software de estadoda- arte. Paralelamente, propõem-se vários métodos heurísticos. Duas das heurísticas propostas são: uma heurística de fluxos em rede e escalonamento e uma heurística de ordenação e escalonamento. Estas heurísticas visam a obtenção de soluções com alguma qualidade em pouco tempo. Propõem-se ainda quatro algoritmos de pesquisa local, que têm em consideração características específicas do problema e que tentam melhorar a qualidade das soluções das heurísticas anteriores. Atendendo ao desempenho dos algoritmos de pesquisa local, estes são combinados através de mudanças sistemáticas das vizinhanças, dando origem a duas meta-heurísticas: uma de descida em vizinhanças variáveis e outra de pesquisa em vizinhanças variáveis. Para avaliar as soluções do modelo de programação inteira mista e dos métodos heurísticos sugere-se uma função de avaliação inovadora, que minimiza os atrasos totais e os níveis em curso de fabrico entre duas etapas sucessivas do processo produtivo. É ainda sugerida uma nova função de avaliação nos métodos heurísticos, também baseada na minimização dos atrasos totais e na minimização dos níveis em curso de fabrico. A principal vantagem desta segunda medida de avaliação é contabilizar de um modo mais rigoroso os níveis em curso de fabrico. Para avaliar o desempenho e a qualidade das soluções do modelo de programação inteira mista e dos métodos heurísticos, desenvolveu-se um gerador de instâncias, que gera instâncias semelhantes às do problema real.This work is associated with the development of models and methods for two medium/short term production planning problems. Our main motivation is the exploration and comparison of different approaches, based on mixed integer programming, on decomposition models and methods and on heuristics, for those two problems. The first one is a classical lot sizing problem associated with the medium-term production planning decisions. The problem consists of finding a production plan for several final items over a given planning horizon that minimizes the overall costs involved, while respecting demand and capacity constraints. An exact model based on a multiple Dantzig-Wolfe decomposition is developed. The general principles of this decomposition are presented in this work too. The potential benefit of this decomposition is the achievement of good quality lower bounds, although our purpose is to obtain integer optimal solutions. The resulting model of multiple Dantzig-Wolfe decomposition is compared with two alternative decomposition models that are obtained when applying directly the Dantzig-Wolfe decomposition principles, and is also compared with an integer programming formulation solved by a state-of-art software. The integer optimal solutions of all the decomposition models are obtained through branch-and-price algorithms. We present computational results for a set of instances from the literature. The second problem studied in this work is a short-term production planning problem that integrates lot sizing, assignment and scheduling decisions. This study was motivated by a real problem from a textile industry. The aim is to define a production plan for a knitting section where the main components of the final items are processed on a set of identical parallel machines. A new mixed integer programming model is proposed for this problem, as well as several heuristics. Two of those heuristics are: a network flow and scheduling heuristic and an ordering and scheduling heuristic. The purpose of these heuristics is to find good quality solutions quickly. Four local search based algorithms that consider specific characteristics of the problem are developed too, in order to try to improve the solutions of the previous heuristics. Taking into account the performance of the four local search heuristics, we combine them through systematic changes of neighborhoods, testing two metaheuristics: variable neighborhood descent and variable neighborhood search. To evaluate the mixed integer programming model solutions and the solutions of all the heuristics, an innovative evaluation function that minimizes a weighted sum of total tardiness and work-in-process levels between two successive production processes is suggested. We study another new evaluation function for the heuristic methods, which is related to the previous one. The main advantage of the second evaluation function over the first one is that it calculates in a more precise way the levels of workin- process inventory. The performance and quality of solutions of all the above presented methods for the second problem are evaluated using a set of instances that are similar to the real ones. Those instances were generated by an instance generator developed by us.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/38582/200

Algoritmos de partição e geração de colunas para dimensionamento de lotes de produção

Dissertação de Mestrado em Engenharia Industrial.Nesta tese, apresentam-se duas aplicações do método de partição e geração de colunas ao problema de lotes de produção multi-artigo capacitado com tempos de preparação. O problema de lotes de produção multi-artigo capacitado com tempos de preparação pode ser descrito como um modelo no qual se procura determinar um plano de produção para vários artigos ao longo de um determinado horizonte temporal, que minimize os custos de produção, de armazenagem e de preparação dos artigos e respeite restrições de procura e de capacidade. A abordagem seguida é a de reformular a formulação de programação inteira mista do problema, utilizando o princípio da decomposição de Dantzig-Wolfe, e combinar o método de geração de colunas com o método de partição e avaliação (método de partição e geração de colunas) para obter soluções óptimas. Na definição da regra de partição utiliza-se uma abordagem baseada nas variáveis binárias do modelo original, que garante a preservação da estrutura do subproblema. A partir da formulação de programação inteira mista do problema, definem-se dois modelos de decomposição: a decomposição por artigo e a decomposição por período e resolvem-se os problemas reformulados através do método de geração de colunas. Para determinar a solução óptima inteira dos problemas reformulados aplica-se o método de partição e geração de colunas. São apresentados resultados de testes computacionais para um conjunto de instâncias com diferentes características, que permitem estabelecer comparações entre os dois modelos de decomposição. Esses resultados computacionais são ainda comparados com a formulação de programação inteira mista que se resolve através de um “solver” de problemas de programação inteira mista, o CPLEX.In this thesis, we present two branch-and-price algorithms to solve the multi-item capacitated lot-sizing problem with setup times. The multi-item capacitated lot-sizing problem with setup times can be seen as a model in which we want to find a production plan for several items over a number of time periods, that minimize the labour costs, inventory costs and setup costs and satisfies all demand requirements without exceeding capacity limits. The approach taken consists in reformulating the mixed integer problem, using the Dantzig-Wolfe decomposition principle, and then combining the column generation method with the branch-and-bound method (branch-and-price method) in order to obtain optimal solutions. In the definition of the branch rule we use an approach based on the binary variables of the original model that assure the conservation of the structure of the subproblem. Based on the mixed integer formulation of the problem, we develop two decomposition models: the item decomposition and the period decomposition and solve the reformulated problems with the column generation method. In order to obtain the integer optimal solution of the reformulated problems we use the branch-and-price method. We present results of the computational tests for a set of instances with different characteristics, to establish comparisons between the two decomposition models. These results are then compared with the mixed integer formulation that we solve by CPLEX, a mixed integer problems solver.Fundação para a Ciência e a Tecnologia (FCT) - (Projecto POSI / 1999 / SRI / 35568).Universidade do Minho (UM). Centro de Investigação Algoritmi

Integration planning of freight deliveries into passenger bus networks: exact and heuristic algorithms

With the increasing population living in cities, a growing number of small daily urban freight deliveries are performed, typically by private companies. Recently, more environmentally friendly urban logistics services have emerged to mitigate the negative effects of such activities. One example is the integration of freight deliveries into bus networks, traditionally dedicated to passenger transportation, to perform urban logistics activities within cities. In this paper, the integration of the freight delivery process into the urban bus passenger network is addressed where freight parcels are dropped by clients at bus hubs located outside the city center, transported by bus services from the hub to bus stops located in the city center, and delivered to the destination address by a last mile operator. Since bus vehicles supporting both passenger and freight flows need to be physically adapted, the aim is to support the decision-maker to select the minimum number of bus services that must be adapted for freight transportation. The optimization problem considers the freight demand uncertainty in terms of number of freight parcels, destination address, delivery time windows and last mile operator constraints which are modelled by a set of demand scenarios. An exact method based on an integer linear programming (ILP) and two heuristic algorithms based on a greedy randomized adaptive search procedure (GRASP) are proposed. The results show that the proposed optimization methods are efficient, giving valuable insights to stakeholders, in the fields of policy and practice, for the strategic decision of selecting the minimum number of buses to be physically adapted for freight transportation. In particular, the results show that all proposed optimization methods are of interest in practice since the type of problem instances for which each method is more efficient is clearly identified in the obtained computational results. Moreover, in the early stages of the integrated passenger and freight flows service, the impact on the required number of adapted bus services is mainly given by the last mile operator capacity of delivering freight from bus hubs to final parcel destinations, while the other factors (delivery time windows and distributions parcel destination addresses) do not have a significant impact on the required number of bus services.publishe

CAUSAS POR LAS QUE SE ACUDE CON MÁS FRECUENCIA AL PROCESO INMEDIATO EN LUGAR DEL PRINCIPIO DE OPORTUNIDAD EN EL DISTRITO FISCAL DE HUÁNUCO, 2016 - 2017

El objetivo general de la presente tesis fue analizar las causas por las que se aplica el proceso inmediato con mayor frecuencia que el Principio de Oportunidad en el Distrito Fiscal de Huánuco, 2016 – 2017, para el desarrollo de la presente el tipo de investigación fue aplicado, el enfoque cuantitativo, nivel descriptivo y diseño no experimental, la muestra fue obtenida mediante la técnica de muestro no probabilístico a conveniencia de la investigadora habiendo tomado el 20.0% de la población siendo la siguiente: 14 Fiscales especializados en lo penal, así como 26 expediente en los que se ha tramitado proceso inmediato y arribado a acuerdo reparatorio durante el 2016 y 36 del 2017. La hipótesis general: existen causas por las que el proceso inmediato es aplicado con mayor frecuencia que el Principio de Oportunidad en el Distrito Fiscal de Huánuco, 2016 – 2017, que son atribuibles a la efectividad, duración del proceso, ha sido comprobada con los resultados obtenidos, de la encuesta aplicada a la muestra y del análisis de los expedientes judiciales, se ha logrado comprobar la hipótesis general, pues en efecto, se ha logrado observar que durante el 2016 y 2017 la aplicación del Proceso Inmediato ha sido más frecuente que el Principio de Oportunidad. Las causas por las que ocurre este fenómeno referidas a la efectividad, corresponde a la eficacia, porque el acuerdo al que se arriba en el proceso inmediato que incoa el Fiscal es más eficaz y garantista que en el Principio de Oportunidad, toda vez que lo resuelve el Juez. Las causas referidas a la duración del proceso; se precisa que acudir al proceso inmediato permite que el fiscal actúe con mayor celeridad, pues incluso en este proceso se puede llegar al Principio de Oportunidad, además sobre la inmediatez procesal, porque el Juez toma contacto directo con la concentración procesal porque permite se actúe con el menor número de actos procesales.Tesi

Characterization of tasks and skills of workers, middle and top managers in the Industry 4.0 context

This study intends to make a characterization of the main tasks and skills needed to face the Industry 4.0. Moreover, it gives special attention to the different company’s hierarchical levels. To achieve the goals of this paper, a methodology based on Collaborative Decision Making method was used. Firstly, thirty participants were interviewed to understand their point of views. Next, they were split into Group Works to refine the results. Finally, a Group Concordance took place to create the final list of tasks and skills. The skills were organized into four categories: Technical, Social, Methodological and Personal. The results show different requirements in each level. In the Workers level, due to the presence of more technical tasks, eight of the top ten skills belong to the Technical category. In the Middle Managers level, there are tasks of both leading and analyzing nature and thus the top ten skills needed are split through the four categories. Finally, in the Top Managers level, due to the presence of mainly strategy tasks, the top ten skills are split between the Methodological and Social categories. To the authors’ knowledge, this is one of the first studies to use a Collaborative Decision Making methodology to develop a set of tasks and skills that future work environments will demand on the different hierarchical levels of the organization.This work was supported by the research unit on Governance, Competitiveness and Public Policy (UIDB/04058/2020) and by Algoritmi Research Unit (UIDB/00319/2020), funded by national funds through FCT—Fundação para a Ciência e a Tecnologia