Modelling and condition-based control of a flexible and hybrid disassembly system with manual and autonomous workstations using reinforcement learning

Remanufacturing includes disassembly and reassembly of used products to save natural resources and reduce emissions. While assembly is widely understood in the field of operations management, disassembly is a rather new problem in production planning and control. The latter faces the challenge of high uncertainty of type, quantity and quality conditions of returned products, leading to high volatility in remanufacturing production systems. Traditionally, disassembly is a manual labor-intensive production step that, thanks to advances in robotics and artificial intelligence, starts to be automated with autonomous workstations. Due to the diverging material flow, the application of production systems with loosely linked stations is particularly suitable and, owing to the risk of condition induced operational failures, the rise of hybrid disassembly systems that combine manual and autonomous workstations can be expected. In contrast to traditional workstations, autonomous workstations can expand their capabilities but suffer from unknown failure rates. For such adverse conditions a condition-based control for hybrid disassembly systems, based on reinforcement learning, alongside a comprehensive modeling approach is presented in this work. The method is applied to a real-world production system. By comparison with a heuristic control approach, the potential of the RL approach can be proven simulatively using two different test cases.

Health, Safety, and Security as a Part of Events Management

The purpose of this chapter is to provide knowledge and propose a methodology for identifying the potential hazards and dealing with health, safety, and security risks in special events. The object of study is special events and the issues caused by their characteristics to concentrate visitors in a certain place for a limited period of time under a planned program. The highlighted issue concerning health, safety, and security in special events is crowd and its management. The author's main thesis is based on the need for a systematic management approach, in which measures are taken for the safety, health, and security of the employees, volunteers, and visitors while planning and conducting an event. This chapter focuses on risk management, which includes identifying potential hazards, risk analysis and risk assessment, measures to prevent or control the risk, as well as developing an action plan. The chapter attempts to provide a comprehensive health, safety, and security risk management framework aimed at special event management and to offer a set of planning and control tools.

Forecasting Shoe Sales Volume with Exponential Smoothing Method at PT Kujang Utama Antasena - Bogor

PT Kujang Utama Antasena is a shoe industry company specifically for security. The purpose of this study is to forecast or predict sales. This study uses a quantitative method with exponential smoothing, smoothing factor/constant (?) of 0.2. In production activities, forecasting is carried out to determine the amount of demand for a product and is the first step of the production planning and control process to reduce uncertainty so that an estimate that is close to the actual situation is obtained. The exponential smoothing method is a moving average forecasting method that gives exponential or graded weights to the latest data so that the latest data will get a greater weight. In other words, the newer or more current the data, the greater the weight.

FINANCIAL SUSTAINABILITY OF THE ENTERPRISE IN MODERN CONDITIONS

The article considers the concept of financial stability of the company in modern conditions, reveals the real situation on this issue, indicates ways to improve the situation. An important direction is to ensure an adequate level of financial stability, which guarantees the rational use of resource potential and stable development in the future. Based on the issues and purpose of the study, an analysis of scientific papers was conducted to determine the concept of financial stability. Differences among scientists in understanding the concept and the problem of lack of clear directions and programs to improve the financial stability of the enterprise are identified. Taking into account the opinions of numerous authors, the determining internal and external factors influencing the financial stability of the enterprise are highlighted. It is determined that today economic and financial factors have the greatest impact on financial stability. The concept of internal and external financial stability is considered. To assess financial stability, it is proposed to use a system of indicators, as one specific group is not enough to characterize the level of stability. The negative consequences of financial instability with unsatisfactory indicators of financial stability are considered. Ways to increase financial stability are proposed. The importance of choosing a financial strategy as a lever in the development of the company is determined. The analysis of the financial stability of the enterprise is considered as a consistent, step-by-step consideration of all parameters related to the conduct of economic activity. Forecasting and analyzing measures to improve financial stability, it is noted that in the modern economy an important component of the process of developing and implementing the financial strategy of the enterprise is financial controlling. The importance of planning and control to ensure financial stability is revealed. Recommendations for stabilizing the company's financial activities have been developed.

Performance During Whole Body Reaching Movements Is Impaired In Hypergravity While Preserved In Microgravity

While recent findings demonstrated the importance of initial state estimates about gravity for optimized motor control, it remains unclear whether novel initial states are rapidly implemented movement planning (and control) in the same way when gravity is removed or increased. Here, we investigated the effect of microgravity and hypergravity exposure on whole-body reaching movements performed by standing subjects during parabolic flights. Reaching movements were analyzed regarding spatial accuracy (finger endpoint deviation), arm kinematics (arm angular displacement), whole-body kinematics (body bending) and EMG activity (muscular activation and synergies) of eight muscles. Results showed that kinematics and muscular activity are adjusted in microgravity allowing accurate whole-body reaching, thus confirming the perfectly scaled sensorimotor reorganization reported in previous recent studies. Contrasting with these observations, participants hardly reached the targets in 1.8g (systematic undershot). Strikingly, whole-body kinematics remained unchanged in hypergravity compared to 1g observations. Finally, while the analysis of synergies highlighted a comparable muscular organization in all gravitational contexts, our main findings revealed local muscular adjustments leading to accurate motor responses in microgravity, but not in hypergravity.

Workload Control and Order Dispatching Rules

The purpose of this study is to choose an order dispatching rule and measure the work-in-process and lead-time in the production process of a conveyor chain manufacturer. The main strategic issue for the manufacturer is dependability, which requires meeting deadlines and managing internal lead-times. The study integrates two techniques, workload control (WLC) and an analytical hierarchy process (AHP), respectively systems for production planning and control, and multi-criteria decision support, both widely used in handling manufacturing strategic issues. The research method is a field experiment. Supported by the AHP and according to strategic criteria, practitioners selected the early due date rule (the order with the closest due date comes first) to release 231 orders. Then, employing a methodology designed to support WLC applications, the study measured key parameters that provide information regarding the overall performance of the manufacturer, the input rate, work-in-process, lead-time, throughput performance, and the level of safety stock. Using the model and a graphical tool derived from queuing theory, the throughput diagram, the study provides evidence that, although the manufacturing process is satisfactorily balanced and achieves acceptable performance, the level of safety stock is small and should be increased to prevent starvation on the shop floor.