Combining simulation and optimization models on a production line problem: A case study

To improve the performance of a production line of a company of the Bosch Group, an optimization model was developed, which produces the optimum allocation of tasks to workstations and workers, according to a set of constraints. These results can thereafter be used in the simulation model, to estimate performance indicators, which would be difficult to estimate with other approaches, namely: waiting times, times spent with displacements and utilization rates. Thus, the purpose of this paper is twofold. First, it describes the combined use of the optimization and the simulation models. Thereafter, it presents the results obtained for 2 scenarios: one without displacements and another with displacements. The former was used to compare the simulation and the optimization models, whilst the later was used to assess the impact of displacements in the production line. By analyzing the results, it was possible to verify that the displacements increased the total time required to produce the devices in more than 10%. Furthermore, it was shown that the displacements caused considerable changes in the remaining performance indicators, indicating the relevance of considering them. This work also brings insights to the Industry 4.0 by proposing an approach to virtualize a production line system, providing the benefits of the 3D visualization of the simulation tool used in this research.This research was partially sponsored by the Portugal Incentive System for Research and Technological Development. Project in co-promotion nº 002814/2015 (iFACTORY 2015-2018) and has been partially supported by FCT –Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2019

Portal Cavernoma Cholangiopathy Secondary to Polycythemia Vera: Case Report and Echoendoscopic Findings

info:eu-repo/semantics/publishedVersio

Relatório de atividade clínica

A Medicina Dentária é a área das Ciências Médicas responsável pelo estudo, diagnóstico, prevenção e tratamento de condições fisiopatológicas que afetam a cavidade oral, os maxilares e as estruturas associadas. A saúde, segundo a Organização Mundial de Saúde, é o estado de bem-estar físico, mental e social de um indivíduo. Porém, a saúde oral é, muitas vezes, relegada para segundo plano, existindo uma mentalidade curativa/restauradora na sociedade atual. Assim, o Médico Dentista deve estimular a prevenção de comportamentos de risco, desde as idades mais precoces, realçando o bem-estar do doente e a promoção da saúde. Pretende-se com este relatório fazer a descrição e reflexão da atividade clínica realizada ao longo do 5º ano curricular do Mestrado Integrado em Medicina Dentária, na Clínica Universitária Dentária da Universidade Católica Portuguesa. O Relatório centra-se no levantamento de dados, exposição e discussão dos atos clínicos realizados, no âmbito das várias Áreas Disciplinares: Medicina Oral, Periodontologia, Dentisteria, Endodontia, Cirurgia Oral, Prostodontia Fixa e Removível, Odontopediatria e Oclusão. Com base nos conhecimentos e princípios apreendidos e a partir da história clínica do doente, do diagnóstico efetuado e dos planos de tratamento elaborados, descrevem-se os atos clínicos realizados, como operador e como assistente. Os dados recolhidos são tratados e divididos por diversas secções e áreas disciplinares, fazendo-se a sua discussão e enquadrando-os teoricamente, dando-se uma especial atenção a casos clínicos de relevo. Face à constante evolução da tecnologia, do conhecimento científico e das suas aplicações na área, é essencial que o Médico Dentista se mantenha atualizado, de modo a permitir uma prática clínica integrada e a elaboração de planos de tratamento multidisciplinares que maximizem a prevenção, o tratamento e o prognóstico das diversas condições e patologiasDentistry is the medical field that concerns itself with the oral cavity, the maxillofacial area and associated structures, from the study and diagnostics to the prevention and treatment of pathophysiological conditions. According to the World Health Organization, health is a state of complete physical, mental and social well-being of an individual. However in the current society, oral health is normally relegated to a secondary position, where a curing/restorative mentality exists. Therefore the dentist should encourage the prevention of risky behaviors, from the earliest age, emphasizing the patient’s well-being as well as the promotion of health. This report’s aim is to describe and reflect upon the clinical activity performed during the 5th year curriculum of Dentistry at the Catholic University of Portugal within the various courses. Based on the knowledge and principles learned, as well as the clinical history of the patient, the diagnosis made and the elaborated treatment plan, the clinical acts are described in the capacity of both surgeon and assistant alike. This data is handled and divided between several sections and subjects, discussing and ultimately framing them in a theoretical context, underscoring relevant clinical cases. Due to the constant advancement of technology, scientific knowledge and its applications in this area, it is essential for a dentist to be kept up to date, so that an integrated clinical practice and the elaboration of an all-encompassing treatment plan that focus on maximizing prevention, treatment and prognosis of the several conditions and diseases may be achieved

Agent-based micro simulation to assess the performance of roundabouts considering different variables and performance indicators

Traffic congestion problems in intersections are usually solved by building infrastructures such as roundabouts. Several variables influence its performance, e.g. geometry, size and driving behaviour. Thus, it becomes necessary to compare these variables. This paper proposes a simulation model, developed to compare the performance of roundabouts, employing the object and agent modelling paradigms of Simio, to model the individual behaviour of vehicles. The results indicate the optimum size of roundabouts is around 40 meters of diameter and that the driving style has a greater influence on the performance of the roundabout than its unbalancing. In addition, it was found that roundabouts considering unbalancing and human behaviour decreased: The flow of vehicles in 8%, the waiting time per vehicle in 3 minutes, the queue size in 90%, the number of stops per vehicle in 88% and vehicles spent three times more fuel, than the roundabouts that did not consider these variables.(undefined)info:eu-repo/semantics/publishedVersio

Assessing the performance of a restaurant through discrete simulation in Simio

For the purpose of evaluating the level of service of a Portuguese self-service restaurant, a simulation model was developed in Simio. The purpose of such model was to quantify specific performance indicators. In this sense, data was gathered by conducting observations of the field, which allowed the authors to find relevant problems in the system. The simulation model was validated and, afterwards, simulation experiments were conducted, which suggested some changes that could be implemented, without reducing the performance of the restaurant and reduce the utilization of workers, who become available for other tasks with more added-value, such as supplying critical items (e.g., main dishes and soap). Moreover, the potential impact of the introduction of an information device used to warn workers responsible to supply items was assessed through simulation, indicating that it would lead to benefits both for customers and workers.This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT –Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013 and by the Doctoral scholarship PDE/BDE/114566/2016 funded by FCT, the Portuguese Ministry of Science, Technology and Higher Education, through national funds, and co-financed by the European Social Fund (ESF) through the Operacional Programme for Human Capital (POCH)

Discrete simulation software ranking -A top list of the worldwide most popular and used tools

This paper documents a work on all-purpose discrete event simulation tools evaluation. Selected tools must be suitable for process design (e.g. manufacturing or services industries). Rather than making specific judgments of the tools, authors tried to measure the intensity of usage or presence in different sources, which they called "popularity". It was performed in several different ways, including occurrences in the WWW and scientific publications with tool name and vendor name. This work is an upgrade to the same study issued 5 years ago (2011), which in its turn was also an upgrade of 10 years ago (in 2006). It is obvious that more popularity does not assure more quality, or being better to the purpose of a simulation tool; however, a positive correlation may exist between them. The result of this work is a short list, of 19 commercial simulation tools, with probably the nowadays' most relevant ones.This work has been co-supported by SI I&DT project in joint-promotion nº 36265/2013 (HMIEXCEL) and by FCT Fundação para a Ciência e Tecnologia - project: PEst-OE/EEI/UI0319/2014. REFERENCESinfo:eu-repo/semantics/publishedVersio

A novel application of pre-signals to improve the performance of signalized intersections: Evaluation through simulation

To ponder less costlier solutions to solve traffic congestion problems at signalized intersections, this paper proposes a novel application consisting of using pre-signals. Hence, an agent-based traffic simulation model was developed, where it is possible to model different types of intersections - including roundabouts of different sizes - and quantify and compare their performance. By analyzing the simulation results, it was found that: on the intersection with pre-signals, an increase in the flow of 10% and 3% was registered, the vehicles spent 1 and 2 less minutes to cross the intersection and the fuel consumption was decreased in 22% and 44%, in comparison to regular intersections and roundabouts, respectively. Concerning the size of queues, it was noted that the queues of the regular intersection were 60 meters longer than the queues on the intersection with pre-signals and on the roundabout. Based on these findings, and by making cost assumptions, a small cost analysis was made, which indicates that at least 1 million € could be yearly saved.This work has been supported by FCT –Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2019

Quemodectoma em cães: relato de caso

O quemodectoma é uma neoplasia derivada dos corpos aórticos e carotídeos, tendo origem neuroectodérmica. Tem sido relatado com maior freqüência em humanos e cães. Destes, os animais braquicefálicos são os mais susceptíveis, notadamente em faixa etária superior a 6 anos. O presente relato se refere a um animal de espécie canina, de raça Boxer, macho, de 7 anos de idade, apresentando histórico de quadro convulsivo e tosse seca. O animal veio a óbito e foi encaminhado ao setor de Anatomia Patológica do Departamento de Patologia da FMVZ-USP. O exame macroscópico evidenciou a presença de hemopericárdio, congestão e edema pulmonares, congestão hepática, renal e edema de vesícula biliar. Porém, o achado macroscópico mais significativo foi a presença de 4 formações tumorais ovaladas na cavidade torácica. O exame histopatológico das formações evidenciou um tecido sólido, altamente celular, com a delimitação de lóbulos através de trabéculas conjuntivas espessas, que emitiam septos delicados subdividindo-os. As células tumorais apresentaram-se uniformes, tendo um formato poliédrico, com núcleo grande esférico, geralmente excêntrico; nucléolo evidente, e cromatina finamente granular; citoplasma de dimensões variáveis e granulação acidofílica delicada. Foi observado pequeno número de figuras mitóticas sem sinais de atipia. Os quadros macro e microscópicos são compatíveis com o diagnóstico de quemodectoma.Chemodectoma is a neoplasm arising from the carotid and aortic bodies, having neuroectodermic origin. It has been related mainly in human beings and dogs. Among the later, the brachiocephalics are the most susceptible, mainly the ones older than six. This case reports a seven year old, male Boxer dog, presenting convulsion and dry cough. The animal died and it was sent to the Pathological Anatomy Section of the Department of Pathology at FMVZ-USP. The post-mort examination revealed the presence of hemopericardium, pulmonar oedema, hepatic and renal congestion and gall bladder oedema, but the most important feature found was the presence of 4 oviform tumoral masses, within the toracic cavity. The histopathology revealed a solid tissue, essentially cellular, with lobules delimitated by delicate septa arising from bands of thick connective tissue. The neoplastic cells presented an homogeneous aspect characterized by a round or polyhedral shape with an excentric and evident nucleoli. There were few mitosis, without atypical signes. The micro and macroscopics aspects are compatible with a chemodectoma diagnosis

A ranking of the most known freeware and open source discrete-event simulation tools

Freeware and open source simulation software can be of great relevant when applying simulation in companies that do not possess the required monetary resources to invest in traditional commercial software, since these can be unaffordable Even so, there is a lack of papers that contribute to literature with a comparison of opensource and freeware simulation tools. Furthermore, such existing papers fail to establish a proper assessment of these type of tools. In this regard, this paper proposes a study in which several freeware and open source discrete-event general purpose simulation tools were selected and compared, in order to propose a ranking based on the tools' popularity, considering several criteria. For this purpose, 30 criteria were used to assess the score of each tool, leading to a podium composed by SimPy, JSim and JaamSim. Further conclusion and future work are discussed in the last section.This work has been supported by FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2019 and by the Doctoral scholarship PDE/BDE/114566/2016 funded by FCT, the Portuguese Ministry of Science, Technology and Higher Education, through national funds, and co-financed by the European Social Fund (ESF) through the Operational Programme for Human Capital (POCH