• Journal of Environmental Health Sciences
• /
• v.30 no.3
• /
• pp.272-282
• /
• 2004

Stress is a primary health promotion issue in worksite research because psychological distress is closely related not only to workers　 health status but also to their job performance. This study identified the work environment and work condition factors affecting workers　 stress symptoms among the Korean manufacturing factory workers. A total of 7,818 factory workers employed in 1,562 manufacturing companies participated in the Korean nation-wide occupational health survey conducted by the Korean Occupational Safety and Health Agency in 2003. Participants were selected by the stratified proportional sampling process by standardized industry classification, company size, and locations. Trained interviewers visited the target companies and interviewed the factory workers randomly selected in each company. Work environments included physical work environments (temperature, noise, hazardous organic compounds, and so on) and psychological work environments (job demands, job control, and social support at work), and work conditions included daily working hour, rest time, and so on. Men were 71.5% and the mean age was 34.0 years old. The average working period in the present company was 6.9 years. The average stress score was 26.2 under the perfect score, 50, which means the moderate level of stress. Perceived stress had significant correlations with young age, poor physical work environment, high fatigue, bad perceived health status, and high job demands in Pearson's simple correlation analysis. Perceived health status and perceived fatigue explained 21% variance of stress symptoms and the work environment factor explained 4.8% of that; however, work condition did not have the sufficient effect. In particular, psychosocial work environment variables (job demand, job control, and social support at work) had a clear effect on stress symptoms rather than the physical work environments. Poor perceived health status, severe perceived fatigue, poor physical work environment, high job demands, low social support, heavy alcohol consumption and little exercise were significantly related to high stress symptoms in the Korean manufacturing workers.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.36 no.2
• /
• pp.81-90
• /
• 2013

Material flow control (MFC) is a kind of operational policy to control of the movement of raw materials, components, and products through the manufacturing lines. It is very important because it varies throughput, line cycle time, and work-in-process (WIP) under the same manufacturing environments. MFC can be largely categorized into three types such as Push, Pull, and Hybrid. In this paper, we set various manufacturing environments to compare five existing MFC mechanisms: Push, Pull, and Hybrid (CONWIP, Gated MaxWIP, Critical WIP Loops, etc). Three manufacturing environments, manufacturing policies (make to stock and make to order), demand (low, medium, high), and line balancing (balanced, unbalanced, and highly unbalanced) are considered. The MFCs are compared in the point of the five functional efficiencies and the proposed compounded efficiency. The simulation results shows that the Push is superior in the functional efficiency and GMWIP is superior in the compounded efficiency.

• International Journal of Quality Innovation
• /
• v.5 no.2
• /
• pp.17-25
• /
• 2004

Despite the fact that much has been published about Six Sigma in the business and academic press and on the Internet in recent years, there is still confusion among many people, particularly those who work in the transactional and service environments, about the nature of Six Sigma. It is true that Six Sigma like other process improvement programs before was first applied to manufacturing processes; however, many corporations including General Electric and Sony have successfully applied Six Sigma to their transactional and service processes as well. Six Sigma is used by many companies not only to improve the quality of their products and services but also to achieve quantifiable financial results, improve management style and communication, and achieve customer and employee satisfaction. Whether in manufacturing or non-manufacturing environments, the application of Six Sigma differs from organization to organization. Although there are many common elements between these applications, however, special care must be taken when customizing Six Sigma to suit the organizations' needs. In this paper, the author provides some practical and useful guidelines for Six Sigma deployment. This paper is not about the use of numerous statistical tools and techniques that can be found in a typical Six Sigma toolbox. The main emphasis has been placed both on the concept and the implementation of Six Sigma, particularly within the non-manufacturing areas of business.

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.1 s.94
• /
• pp.161-166
• /
• 1999

Virtual Manufacturing System(VMS) is a computer model that represents the precise and whole structure of manufacturing systems and simulates their physical and logical behavior in operation. In this paper, a real time simulation for the virtual factory is proposed to integrate a process planning with scheduling under distributed environments. In order to communicate the information under distributed environments, we use a server/client concept using socket program and internet.

• Journal of Korean Society for Quality Management
• /
• v.20 no.2
• /
• pp.118-128
• /
• 1992

The determination of appropriate buffer capacity is an important issue in the design of the advanced manufacturing systems and closely related to the system efficiency and flexibility. Work-in-process is usually not desirable. However, in reality, maintaining some capacity of buffer storage is inevitable in compensation for the machine blocking and break down. The objective of this paper is to present analytical methods and tools for the buffer capacity planning in the Flexible Manufacturing System Environments. The effects when machine blocking is critical factor are also discussed.

• Journal of Environmental Health Sciences
• /
• v.3 no.1
• /
• pp.27-44
• /
• 1976

This study was carried out to evaluate the harmful factors in working environments and to investigate the labor productivity after improvement of environments, surveying 93 industrial establishments of 10 industries located in Youngdeungpo industrial area in Seoul. The results obtained were as follows: 1) The highest noise level of 125dB(A) was indicated at the rolling process of transport equipment manufacturing industry. 2) The best illumination level was shown in precise machinery industry and the worst was indicated in rubber products, metallic products and transport equipment manufacturing industries. 3) Thermal conditions were above threshold limit value (TLV) at more than two processes of all industries except printing industry. 4) The highest dust concentration was determined in textile and wearing manufacturing industry. 5) Organic solvents were detected at 52 processes in 93 industrial establishments and 33 processes of them showed higher than TLV. The results about harmful chemicals were as follows: a) sulfur dioxide ($SO_2$)was determined higher than TLV on welding process of metallic product manufacturing industry and heat treatment process of transport equipment manufacturing industry. b) Carbon monoxide (CO) concentration was 700ppm at heat treatment process of transport equipment manufacturing industry, indicating 14 times of TLV. c) vinylchloride concentration in the air of PVC raw material mixing process and PVC preparation process of chemical product manufacturing industry was determined higher than TLV. d) Hydrochloride (HCl) concentration in the air of wire expanding process of transport equipment manufacturing industry was determined higher than TLV. 7) Higher values of lead concentration than TLV were determined at lead welding metallic product manufacturing industry and type planting process of process of printing industry, $1.8mg/m^3$ and $0.3mg/m^3$ respectively. 9) 22, 968 of 52, 855 workers (i.e. 43.5%) in 93 industries were exposed to various harmful agents. 10) It was found that the improvement of illumination in electric apparatus manufacturing industry (from 20~40 lux to 420 lux) resulted in an increase in productivity of 6.5% per capita and a decrease in faulty products of 19%. 11) Improvement of environments using local exhaust ventilation system resulted in a decrease of harmful substances lower than TLV and an increase in productivity of 11.4%. 12) Improvement of shovelling tools based on ergonomics resulted in a reduction in energy expenditure of 25.3% and an increase in productivity of 32.2% per capita.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.31 no.4
• /
• pp.121-133
• /
• 2008

In manufacturing companies, engineering information is a central data which defines a product to be produced. This is changed by various factors such as changes of product configuration, changes of drawings information of a technology's licensor, etc, and these changes essentially accompany the changes of a product BOM (Bill of Materials) structure. Thus, engineering changes gives a heavy burden to information management within enterprise because the changes of product BOM have an influence on each departmental BOM such as a procurement BOM, a manufacturing BOM, a quotation BOM, etc. Especially, these changes of product BOM due to the engineering changes is inevitably and frequently happened by a customer's requirements in a customer-oriented make-to-order manufacturing environments. In these manufacturing environments, information gap among each department from the first contact point of customer to engineering, materials, production, quality, and management is very close, and thus it is very important that the change information of product BOM due to changes of product specification and engineering information are efficiently communicated among each department. This paper describes a procedure of determining product specification and of generating product BOM, and proposes an efficient management scheme for the change process of product BOM information due to changes of product specification and engineering. Also, to show the effectiveness of the proposed product BOM management scheme, a product BOM management system is implemented for the ship engine division of 'H' company, one of customer-oriented make-to-order manufacturing enterprises.

• Journal of Energy Engineering
• /
• v.26 no.3
• /
• pp.11-29
• /
• 2017

In recent years, the use of artificial intelligence technology such as deep neural net machine learning(deep learning) is becoming an effective and practical option in industrial manufacturing process. This study focuses on recent deep learning development environments and their applications in the manufacturing field.

• The Journal of Korea Robotics Society
• /
• v.18 no.2
• /
• pp.225-232
• /
• 2023

With the recent increase of multiple robots cooperating in smart manufacturing logistics environments, it has become very important how to predict the safety and efficiency of the individual tasks and dynamically assign them to the best one of available robots. In this paper, we propose a novel task policy learner based on deep relational reinforcement learning for predicting the safety and efficiency of tasks in a multi-robot manufacturing logistics environment. To reduce learning complexity, the proposed system divides the entire safety/efficiency prediction process into two distinct steps: the policy parameter estimation and the rule-based policy inference. It also makes full use of domain-specific knowledge for policy rule learning. Through experiments conducted with virtual dynamic manufacturing logistics environments using NVIDIA's Isaac simulator, we show the effectiveness and superiority of the proposed system.

• IE interfaces
• /
• v.14 no.3
• /
• pp.326-333
• /
• 2001

The purpose of this paper is to empirically investigate the relationships between market environments and technology strategy using the data gathered from Korean manufacturing firms. As the significant environmental factors influencing company's technology strategy, two sorts of market aspects are considered; market competition factor and technological dynamics factor. And companies are categorized with respect to the characteristics of market environments they are facing with. Then we seek to find the differences in the contents of technology strategy among the companies in different types of environments through statistical analysis. As a result, it is found that there exist significant relationships between the companies' technology strategy and the environments facing firms.