Web-Based Simulation: Evolution or Revolution?

ACM Transactions on Modeling and Computer Simulation, Vol. 10, No. 1, January 2000, Pages 3–17

Simulação de tempo necessário para atender toda a fila de cirurgias eletivas de um hospital

Orientador : Doutor Professor Gustavo Valentim LochMonografia (especialização) - Universidade Federal do Paraná, Setor de Tecnologia, Curso de Especialização em Engenharia de Produção.Inclui referênciasResumo : A espera dos pacientes na fila de cirurgias é um drama de milhares de pacientes no Brasil. Levando em conta a importância social neste aspecto, a presente pesquisa simulou os tempos de cirurgias eletivas de um hospital público no Paraná para melhorar a distribuição de recursos e pessoal, minimizando custos e aumentando a qualidade de atendimento. Após a coleta de dados e identificação de distribuições de probabilidade que modelam diferentes tipos de cirurgia, foram realizadas simulações para estimar o tempo total necessário para atender todos os pacientes que estão nas respectivas filas de cirurgias. Os resultados sugerem quais as chances de atender a todas cirurgias e auxilia a tomada de decisão da diretoria do hospital quanto ao tempo de cirurgia que está intimamente ligada ao tempo de espera e satisfação dos pacientes e de seus familiares. Este estudo pode viabilizar ainda uma melhor organização e planejamento de pessoal e recursos do hospital, podendo ser utilizado também pelo departamento financeiroAbstract : The waiting of patients in the queue of surgeries and a drama of thousands of patients in Brazil. Taking into account the social importance in this aspect, the present research simulated the elective surgery times of a public hospital in Paraná to improve the distribution of resources and personnel, minimizing costs and increasing the quality of care. After the data collection, It was performed 1000 simulations for 3 scenarios, for the total time of 100, 200 and 400 surgeries. The results suggest the chances of attending all surgeries and help the decision-making of the hospital's board regarding the time of surgery that is closely linked to the waiting time and satisfaction of patients and their families. This study can also make viable a better organization and planning of hospital personnel and resources, and can even be used by the financial department

Simulateur d'activités de la vie quotidienne et validation de scénario

La simulation des activités de la vie quotidienne (AVQ) dans le contexte des habitats intelligents a pour but l'obtention rapide et massive de données similaires aux sorties des capteurs qui composent l'habitat intelligent. Rapide, pour ne pas avoir à observer une même activité pendant plusieurs mois, massive pour obtenir une base de connaissances substantielle des activités à observer. Pour atteindre cet objectif, les concepts relatifs aux AVQ tels que la composition des activités, les ressources et les paramètres que l'on souhaite observer doivent être extraits du monde réel pour être transposés dans le monde de la simulation. Le processus de développement du simulateur d'AVQ prend l'observation du monde réel comme point de départ et décrit les étapes qui amènent à l'implémentation puis à la validation du simulateur. Le simulateur, ayant déjà fait l'objet d'un travail de maîtrise, a été refactorisé pour dégager les différents concepts relatifs aux AVQ avant d'être validé. Dans ce contexte, nous abordons d'une part, la méthodologie liée à la refactorisation du code original du simulateur pour refléter plus précisément le monde réel et faciliter l'ajout de fonctionnalités nécessaires au bon déroulement de la simulation. D'autre part, nous étudions les techniques de validation existantes et proposons celles à implémenter pour valider le simulateur d'AVQ. Nous implantons deux techniques, le data historical validation et la validation par animation, que nous testons sur un scénario observé dans le milieu réel

A Robust Aggregation Approach To Simplification Of Manufacturing Flow Line Models

One of the more difficult tasks facing a modeler in developing a simulation model of a discrete part manufacturing system is deciding at what level of abstraction to represent the resources of the system. For example, questions about plant capacity can be modeled with a simple model, whereas questions regarding the efficiency of different part scheduling rules can only be answered with a more detailed model. In developing a simulation model, most of the actual features of the system under study must be ignored and an abstraction must be developed. If done correctly, this idealization provides a useful approximation of the real system. Unfortunately, many individuals claim that the process of building a simulation model is an “intuitive art.” The objective of this research is to introduce aspects of “science” to model development by defining quantitative techniques for developing an aggregate simulation model for estimating part cycle time of a manufacturing flow line. The methodology integrates aspects of queueing theory, a recursive algorithm, and simulation to develop the specifications necessary for combining resources of a flow line into a reduced set of aggregation resources. Experimentation shows that developing a simulation model with the aggregation resources results in accurate interval estimates of the average part cycle time

Evaluation of monorail haulage systems in metalliferous underground mining

The decline is a major excavation in metalliferous mining since it provides the main means of access to the underground and serves as a haulage route for underground trucks. However, conventional mining of the decline to access the ore body poses economic and technical challenges that require innovative responses. The average cross-sectional area of mine declines in Australia is 5m wide x 5m high. The large excavations associated with current underground mining practices are economically and geotechnically inappropriate, especially for narrow vein mining conditions. The decline gradient of 1 in 7 (8[superscript]o) designed to accommodate truck haulage results in a significantly longer decline compared to a decline mined at a steeper gradient. Further, the current drill-blast-load-haul cycle does not allow rapid development of the decline to access the ore body since the cycle is made up of discontinuous segments. The use of diesel equipment poses health risks and increases ventilation requirements. The heat load and air borne exhaust contaminants emitted by large diesel engines create heavy demand on mine ventilation, sometimes resulting in substandard working conditions. As mines get deeper, there is a tendency to increase the truck and loader fleet – which results in traffic congestion in the decline. Metal prices in the recent boom may have helped to offset some of the shortcomings of current practices, and although the good times may continue, a down-turn could find many operations exposed. Federal government emissions trading scheme encourage mining companies to reduce carbon emissions in their operations.This study was prompted by the need to investigate the potential of the monorail haulage system in metalliferous mining, particularly in decline development and main haulage in view of shortcomings of the current practices. Monorail systems are being used in mines around the world for material transport and man-riding but their utility in rock transport has not been fully investigated. Hence, it is proposed to replace non-shaft component of the mine haulage system with roof/back mounted monorail technology using continuous conductor technology to provide competitive haulage rates in substantially smaller excavations at steeper gradient than is currently achievable. It is proposed that a suite of equipment can be adapted or modified to enable development of the decline supported by the monorail system.To this end, a drill system mounted on the monorail accompanied by a pneumatic system for loading rock into monorail containers is proposed. The proposed decline gradient for the monorail decline is 1 in 3 (or 20[superscript]0) with a cross-sectional area of 4m wide x 4m high. Decline dimensions of size 4.0m x 4.0m (minimum opening for monorail system is 3m x 3m) are used in this design in order to leave enough working space (underneath and on the sidewalls) and to accommodate other mine services, such as, ventilation tubing, air and water pipes and cables. Systems analysis, engineering economics and computer simulation are used to evaluate the feasibility of the monorail mining system for decline development. Technical data relating to the operation of monorail systems in underground mining was obtained from Solutions for Mining Transport (SMT) – Scharf, of Germany, a company that manufactures monorail systems. Monorail haulage has definite advantages over conventional haulage; these include the use of electrical power instead of diesel, steeper gradients (up to 36[superscript]0), smaller excavations, tighter horizontal and vertical turning radii and potential for automation. The concepts are applied to a narrow vein ore deposit with results indicating that the monorail system delivers significant savings in terms of time and cost of decline development in this specific application.Stability of the monorail drilling system is critical in ensuring high performance of the drilling system. Stabilisation of the system requires determination of the horizontal, vertical and lateral forces of the system. According to the findings, these forces depend on the vector position of the two drilling booms that will be mounted onto the monorail train. Therefore, the research provides minimum and maximum monorail system reaction forces in horizontal and vertical stabilisers that will stabilise the system during drilling operations. Because of the configuration and positioning of the monorail drilling system, the research has also shown that with appropriate swing angles and lifting angles that will enable the system to reach the whole drill face during drilling operations.Since pneumatic or suction system is used during loading process, the research has revealed that the density of rock fragments, rock fragmentation, conveying air velocity and the negative pressure of the system would greatly influence the loading time and power consumption of the system. Therefore, the study has determined optimum fragmentation of the pneumatic system for various conveying air velocities. Additionally, for the efficient operations of the system, a range of conveying air velocities that give optimal mass flow rate (mass flow rate that give shorter loading time) and optimal power consumption have been determined at maximum negative pressure of 60kPa (0.6 bars).Since the monorail drilling and loading systems move on the rail/monorail installed in the roof of the decline and supported by roof bolts, suspension chains and steel supports, the strength of the support system is critical. To avoid system failure, it is imperative that the force in each roof bolt, suspension chain and steel support capable of suspending the weight of the heaviest component of the system is determined. Through the models developed, this study has determined the minimum required strength of roof bolts, suspension chains and steel supports that can suspend and support the components of the drilling and loading systems.To increase the efficiency and improve the safety of the two systems, the automation design for monorail drilling and loading systems’ processes have been developed. The proposed automation system would increase productivity by improving operator performance through control of the two systems’ processes. It is hoped that automation of the monorail drilling and loading systems will reduce the total drill-load-haul cycle time hence improving the efficiency of the systems.The application of simulation techniques was deemed useful to determine the performance of the monorail system in mining operations. During modelling, a simulation programme was written using General Purpose Simulation System (GPSS/H) software and results of the simulation study were viewed and examined in PROOF animation software. According to simulation results, the monorail system will have the same advance rate as conventional method since both systems have one blast per shift. However, the total drill-blast-load-haul cycle time for the monorail system is lower than for conventional method.Since the monorail system poses health and safety challenges during operations, through risk analysis, this study has identified root factors that have the potential to cause monorail system risk and hazard failure. The research has revealed that lack of maintenance of the monorail system and the monorail installations, production pressure and insufficient training of personnel on monorail system use are the major root factors that have the potential to cause risk and hazard failure. In order to improve the health and safety of the system, the study has suggested risk and hazard control strategies which are aimed at reducing the level of risk by directing corrective measures at potential root causes as opposed to addressing the immediate obvious symptoms such as monorail falling from support system, monorail running out of control, and others.A mine design case study using a monorail technology was conducted using one of ‘South Deeps’ gold deposits of Jundee mine operations (owned by Newmont Mining Corporations). Nexus deposit, one of ‘South Deeps’ deposits, was selected as case study area. The case study indicates that development of decline access to Nexus deposits using monorail technology is feasible. Compared with conventional decline development, results have shown that the monorail system has the potential of reducing the decline length to Nexus deposits by over 62.6% and decline costs by 63% (i.e., spiral decline and straight incline from the portal only). Furthermore, the study indicates that with the monorail system, there is a potential of reducing the total capital development costs to Nexus deposit by 22% (i.e., cost of developing the spiral decline, straight incline from the portal, crosscuts, ventilation network and installation and purchase of monorail train). Also, due to shorter decline length coupled with smaller decline openings, the duration of decline development reduces by 71.8%

An Integrated Thermal Simulation & Generative Design Decision Support Framework for the Refurbishment or Replacement of Buildings: A Life Cycle Performance Optimisation Approach

The environmental performance of existing buildings can have a major role in achieving the CO2 reduction targets, set out by the UK government. In the UK, new buildings account for around 1% of the total building stock (annually), and predictions show that around 75% of the housing stock that will still remain in 2050 has already been built. Furthermore, while current building performance improvement efforts focus mainly on the operational performance of buildings, the environmental impact of the built environment is the result of processes that occur throughout their whole life-cycle (construction, usage and demolition). To achieve significant CO2 emission reductions in the built environment in an economically viable way, this thesis adopted the Life Cycle Carbon Footprint (LCCF) and Life Cycle Cost (LCC) analysis approaches, to enable a cross-comparison between multiple design alternatives and to identify the preferable design solution: the refurbishment of existing buildings or their replacement by new ones. In particular, this thesis has developed, tested and validated a computational framework that integrates life cycle performance protocols (EN 15978:2011 and BS ISO 15686-5), thermal simulation tools (EnergyPlus), mathematical optimisation (NSGA-II) and a designated building generative design programming (PLOOTO - Parametric Lay-Out Organisation generator) into a single computer application. The investigation was carried out using a comparative analysis of simulated case study buildings: a terrace-house, a bungalow and a block of flats. Results show that under the considered assumptions, the optimal refurbishment case studies achieved lower LCCF and LCC values than the replacements: The LCCF of the refurbishment scenarios was between 1,100-1,500 kgCO2e/m2 and their LCC 440-680 £/m2, compared to those of the replacements scenarios, who achieved between 1,220-1,850 kgCO2e/m2 and 550-890 £/m2. Furthermore, this research has found that optimising the performance of a typical London-based terrace house using a life cycle carbon approach reached 10% more savings in CO2 throughout its life, compared to targeting operational CO2 only. This means that complying with current UK regulations – which is currently only focused on the improvement of operational efficiencies – may result in buildings with poorer performance, in terms of their overall life cycle carbon footprint. This is associated to the difference in the analysis scope: while operational efficiencies only examine emissions due to heating and lighting within the building, the Life Cycle approach accounts for emissions that occur in other stages in the building’s life, e.g., emissions that are embodied within its structure, emissions during construction, maintenance and more. An important conclusion of this research is, therefore, that to reach significant reductions in emissions rates – a life-cycle approach should be adopted. More specifically, to achieve immediate reductions (on a 20-year scale) - refurbishments are generally preferable over replacements. It can, therefore, be concluded that there is a greater importance in incentivising re-use to achieve quicker emissions reductions. The research has shown that the integration of the various research tools in the proposed computational framework was successful in automating the analysis process. The comparative analysis approach was found to be useful in identifying the preferable design solution – the refurbishment of existing buildings or their replacement. Finally, the research sets out an extensive discussion in regard to the proposed computational framework, life cycle performance analysis and the potential benefits of refurbishments or replacements of existing buildings, in the context of the UK

A TUTORIAL VIEW OF SIMULATION MODEL DEVELOPMENT

Working from the background of simulation language developments, we develop an understanding of the current status of simulation model development. Factors characterizing the current status include a shift in emphasis from program to model, more commitment to modeling tools, and the lingering impedance of simulation language isolation. Current and future needs are identified. Specific approaches to meeting these needs are cited in an extensive description of current research, and in summary we conclude that the technology of simulation model deyelopment is in a transitional period that portends more rapid changes for the future