Review of governance models production lines manufacturing systems

В статье приведен обзор основных моделей управляемого производственного процесса, используемых для проектирования систем управления современными поточными линиям. Выполнен сравнительный анализ разных типов моделей и показаны области применения моделей. Дана краткая характеристика основных параметров моделей. Детально рассмотрены кинетические модели и потоковые модели с использованием уравнений в частных производных.The article provides an overview of the main models managed manufacturing process used for the design of control systems with modern flow lines. A comparative analysis of different types of models and shows the application of models. A brief description of the main parameters of the models. A detailed analysis of kinetic models and flow models using partial differential equations

Evaluating the Impacts of Vaccination, Antiviral Treatment and School Closure on Influenza Epidemic

Multi-objective simulation optimization was performed to synergistically investigate the cost and benefits of the most commonly-used strategies for H1N1 epidemic mitigation: vaccination, antiviral treatment, and school closure. By simultaneously considering the three intervention strategies, this study leads to findings that supplement those in the existing work, and provides additional insights regarding intervention decision making. Specifically, our investigation suggests that different vaccine prioritization strategies, the age-based versus ACIP (Advisory Committee on Immunization Practices) recommendation, be implemented depending on vaccine availability; individual school closure policies are favored over their global counterparts, at least when both vaccination and antiviral treatment are implemented with relatively plentiful medicine supply. The trade-offs of cost and benefits of the intervention strategies were investigated, and can be used to support relevant decision making

Обзор моделей управляемых производственных процессов поточных линий производственных систем

В статье приведен обзор основных моделей управляемого производственного процесса, используемых для проектирования систем управления современными поточными линиям. Выполнен сравнительный анализ разных типов моделей и показаны области применения моделей. Дана краткая характеристика основных па-раметров моделей. Детально рассмотрены кинетические модели и потоковые модели с использованием уравнений в частных про-изводных

A new perspective on Workload Control by measuring operating performances through an economic valorization

Workload Control (WLC) is a production planning and control system conceived to reduce queuing times of job-shop systems, and to offer a solution to the lead time syndrome; a critical issue that often bewilders make-to-order manufacturers. Nowadays, advantages of WLC are unanimously acknowledged, but real successful stories are still limited. This paper starts from the lack of a consistent way to assess performance of WLC, an important burden for its acceptance in the industry. As researchers often put more focus on the performance measures that better confirm their hypotheses, many measures, related to different WLC features, have emerged over years. However, this excess of measures may even mislead practitioners, in the evaluation of alternative production planning and control systems. To close this gap, we propose quantifying the main benefit of WLC in economic terms, as this is the easiest, and probably only way, to compare different and even conflicting performance measures. Costs and incomes are identified and used to develop an overall economic measure that can be used to evaluate, or even to fine tune, the operating features of WLC. The quality of our approach is finally demonstrated via simulation, considering the 6-machines job-shop scenario typically adopted as benchmark in technical literature

The Overview of Manufactured Systems Models

The article provides an overview of the main models of manufacturing systems. Here a comparative analysis of different types of models and shows their applications. In this article A brief description of the main model parameters. The detailed analysis of the streaming models with the using of partial differential equations. In this article is their classification depending on the equation of state. We examined the cross-sectional and two-moment description of the production process.У статті наведено огляд основних моделей виробничих систем. Виконано порівняльний аналіз різних типів моделей і показано області їх застосування. Надана коротка характеристика основних параметрів моделей. Детально розглянуто потокові моделі з використанням рівнянь в частинних похідних. Проведена їх класифікація залежно від виду рівняння стану. Розглянуто одномоментний і двохмоментний опис виробничого процесу.В статье приведен обзор основных моделей производственных систем. Выполнен сравнительный анализ разных типов моделей и показаны области их применения. Дана краткая характеристика основных параметров моделей. Детально рассмотрены потоковые модели с использованием уравнений в частных производных. Проведена их классификация в зависимости от вида уравнения состояния. Рассмотрено одномоментное и двухмоментное описание производственного процесса

Optimization and Simulation of Manufacturing Systems

Production planning and scheduling are critical in matters of cost reduction and performance improvement, crucial factors due to the highly competitive nature of today's industry. The technological development allowed the emergence of hybrid methods of optimization and simulation to perform the referred actions with better results.The proposed method consists in the interaction between a Linear Programming model and a simulation model, being the latter used as an evaluator of the solution proposed by the first. In the case of an impossible solution, the simulation results will serve as input to the LP model to adjust some parameters in an intent to produce more realistic results. The proposed methodology was applied to a case study concerning a make-to-order company, JPM Indústria.The expected results should prove the proposed method to outperform other commonly used methods, and be satisfactory in handling the case study's problems, namely its bottleneck situation. Moreover, the results should support the proposed method as a viable alternative for production planning and scheduling problems

Investigation of production planning for environmental sustainability improvement in polymer LPBF

Additive Manufacturing (AM), also known as 3D printing, refers to a family of manufacturing technologies that use a layer-by-layer approach to converting digital models into physical components. The adoption of AM has offered significant sustainability benefits such as improved resource efficiency, extended product life, and reconfigured value chains. However, despite these prospective benefits, the full potential of the sustainable aspects of AM has not been explored, due to a lack of knowledge regarding environmental sustainability improvement in AM. This thesis documents work on investigating the environmental sustainability improvement in polymer Laser Powder Bed Fusion (LPBF) from a production planning perspective. Three studies were performed to understand how to improve the environmental sustainability of AM: modelling, optimisation, and network effects investigation. The modelling study revealed environmental sustainability elements in polymer LPBF and their share in the environmental impacts of polymer LPBF. To do this, a layer-based environmental sustainability model was established. In this model, the build time, energy consumption, embedded energy, material consumption, and risk of build failure were considered. It was shown that embedded energy dominated the total energy consumption (approximately 40 to 60%). Meanwhile, the energy relevant to risk of build failure contributed to approximately one third of expected total energy consumption at full capacity utilization. The study of optimisation demonstrated that integrated optimisation plays a significant role in improving energy efficiency during the additive process. In this study, an exploratory simulation was used to investigate integrated optimisation through the system (or computational tool) development. Building on this, a new framework of integrated optimisation was established. Build volume packing and scheduling were jointly optimized. Specifically, a bottom-left heuristic, capacity aggregation algorithm and exhaustive search were used to support integrated optimisation. Specific energy consumption was regarded as the optimisation objective. It was found that integrated optimisation approach had a significant effect on improving energy efficiency of polymer LPBF at higher demand profiles. The developed system allowed a lower specific energy consumption during the additive process than the results in extant literature. The study of network effects revealed the extraordinary potential for environmental sustainability improvement in polymer LPBF by investigating the environmental network effects in the AM platform. Environmental network effects reflect the mutual impact regarding quantity and benefits (i.e., energy efficiency and lead time) between customers and machine operators (or manufacturers) in AM platform. Specifically, machine operators are assumed to care about energy efficiency (i.e., specific energy consumption) and customers are assumed to concern lead time (i.e., schedule attainment). Another computational tool was developed to support this investigation. A build volume-based capacity aggregation algorithm was developed in this system. Specific energy consumption and schedule attainment were considered as the metrics to uncover environmental network effects in the AM platform. It was shown that there were indirect network effects embedded in the AM platform. These powerful effects are likely to help manufacturers improve energy efficiency and help customers reduce waiting time. Based on integrated optimisation, using network effects in the AM platform shows greater performance in improving the environmental sustainability of AM

Investigation of production planning for environmental sustainability improvement in polymer LPBF

Additive Manufacturing (AM), also known as 3D printing, refers to a family of manufacturing technologies that use a layer-by-layer approach to converting digital models into physical components. The adoption of AM has offered significant sustainability benefits such as improved resource efficiency, extended product life, and reconfigured value chains. However, despite these prospective benefits, the full potential of the sustainable aspects of AM has not been explored, due to a lack of knowledge regarding environmental sustainability improvement in AM. This thesis documents work on investigating the environmental sustainability improvement in polymer Laser Powder Bed Fusion (LPBF) from a production planning perspective. Three studies were performed to understand how to improve the environmental sustainability of AM: modelling, optimisation, and network effects investigation. The modelling study revealed environmental sustainability elements in polymer LPBF and their share in the environmental impacts of polymer LPBF. To do this, a layer-based environmental sustainability model was established. In this model, the build time, energy consumption, embedded energy, material consumption, and risk of build failure were considered. It was shown that embedded energy dominated the total energy consumption (approximately 40 to 60%). Meanwhile, the energy relevant to risk of build failure contributed to approximately one third of expected total energy consumption at full capacity utilization. The study of optimisation demonstrated that integrated optimisation plays a significant role in improving energy efficiency during the additive process. In this study, an exploratory simulation was used to investigate integrated optimisation through the system (or computational tool) development. Building on this, a new framework of integrated optimisation was established. Build volume packing and scheduling were jointly optimized. Specifically, a bottom-left heuristic, capacity aggregation algorithm and exhaustive search were used to support integrated optimisation. Specific energy consumption was regarded as the optimisation objective. It was found that integrated optimisation approach had a significant effect on improving energy efficiency of polymer LPBF at higher demand profiles. The developed system allowed a lower specific energy consumption during the additive process than the results in extant literature. The study of network effects revealed the extraordinary potential for environmental sustainability improvement in polymer LPBF by investigating the environmental network effects in the AM platform. Environmental network effects reflect the mutual impact regarding quantity and benefits (i.e., energy efficiency and lead time) between customers and machine operators (or manufacturers) in AM platform. Specifically, machine operators are assumed to care about energy efficiency (i.e., specific energy consumption) and customers are assumed to concern lead time (i.e., schedule attainment). Another computational tool was developed to support this investigation. A build volume-based capacity aggregation algorithm was developed in this system. Specific energy consumption and schedule attainment were considered as the metrics to uncover environmental network effects in the AM platform. It was shown that there were indirect network effects embedded in the AM platform. These powerful effects are likely to help manufacturers improve energy efficiency and help customers reduce waiting time. Based on integrated optimisation, using network effects in the AM platform shows greater performance in improving the environmental sustainability of AM