• Journal of the Ergonomics Society of Korea
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• v.29 no.4
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• pp.423-433
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• 2010

The presence of musculoskeletal burden tasks and work related musculoskeletal disorders (WMSDs) at Industrial workers was not well-known until 2000 in Korea. Since The Occupational Safety & Health Law was registered a business of proprietor duty in preventing work-related MSDs of workers In July of 2003 WMSDs became a big issue in Korea. A social previous interest was focused on the manufacturing industry just like auto and shipping industry in manufacturing sectors but nowadays it is spreading out to non-manufacturing fields gradually. Nevertheless, we have WMSD prevention Law and System in Korea to reduce WMSDs effectively and systematically we recognized some mistakes and problems of WMSD Law and System. In this paper we study these recent problems in Korea from about 10 years experience and proposed some proposals as discussion.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.2 no.4
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• pp.46-52
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• 2003

For position control of electro-hydraulic servo system, single rod cylinders and double rod cylinders are used. Single rod cylinders have simple structure for manufacturing but different volume ratio of two sides induce to non-linearity in process of then mathematical modeling. So only with conventional PID control method it is difficult to control single rod cylinders precisely. For mole precise position control of single rod cylinders, a controller which is inserted a velocity feedback PID controller and MRAC controller are proposed. With experiment control performances of three control methods are compared. In case of experiment, for external varying load to the system, a hydraulic cylinder and a pressure control valve are used. In conclusion a MRAC is considered a suitable control method for external varying load.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.6
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• pp.745-750
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• 2011

A jig vise is a device to clamp workpiece precisely, which is widely used for various machine tools and manufacturing purpose. A new elastic structured jaw-wedge of jig vise is developed, in this paper, so as to satisfy the clamping requirement and the suppression effect of upright movement of workpiece. The advanced design parameters of jaw-wedge are derived step by step considering the stress distribution and the displacement profiles of ANSYS analysis, and it could find the optimum model which shows the uniform displacement profiles and exhibits the non-concentrated stress distribution of jaw neck. As a result, it is ascertained that an jaw-wedge developed in this study is the simple elastic structure which is effective for automatic multiple clamping purpose without the danger of shear crack or bucking of jaw.

• Journal of the military operations research society of Korea
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• v.22 no.2
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• pp.126-138
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• 1996

The statistical control chart has been proven to be the effective tool most widely used in the manufacturing industry for monitoring and controlling the manufacturing processes. However, the Shewhart chart sometimes gives us false information when the distribution of quality characteristics is skewed. Therefore, it cannot serve as the universal quality control chart if there exist odd events in the manufacturing process. The objective of this study is thus to develop the new technique for constructing the limits of quality control chart based on a sample median and range when the distribution of the underlying population is skewed. This new control chart can effectively solve and manage the processes which have the non-normally distributed quality characteristics frequently occurring in the practical situation.

• KSBB Journal
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• v.31 no.2
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• pp.91-99
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• 2016

Tea is an aqueous infusion of dried leaves of the plant Camellia sinensis L. and is the second most widely consumed beverage around the world after water. Aroma compounds of tea differ largely depending on the manufacturing process, even from the same categories of different origins. The flavor of tea can be divided into two categories: taste (non-volatile compounds) and aroma (volatile compounds). In the present study, we review the formation mechanism of main aromas generated from carotenoids, lipids, glycosides as precursors, and Maillard reaction during the tea manufacturing process, with biological and chemical mechanisms.

• Journal of Information Technology Applications and Management
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• v.24 no.2
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• pp.55-70
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• 2017

A key factor of competitiveness of a firm is technology innovation including product and process innovation. This paper explores the importance and performance of innovation in IT industry across manufacturing and service business. Using importance-performance analysis based on a survey of Korean manufacturing and service firms, we find the characteristics of innovation in IT under the context of industry difference. Out study indicate that Korean IT firms need to recognize the importance of technology innovation and enhance the performance in some areas. In future research, we will expand the boundary of innovation into non-technology innovation as well as service-specific innovation.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.4
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• pp.271-280
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• 2016

Predicting cutting forces in machine tools is essential to productivity improvement and process control in the manufacturing field. Furthermore, milling machining is more complicated than turning machining. Therefore, several studies have been conducted previously to simulate milling forces; this study aims to simulate the cutting forces in milling machines using multi-layered neural networks. In the experiments, the number of layers in these networks was 3 and 4 and the number of neurons in the hidden layers was varied from 20 to 200. The root mean square errors of simulated cutting force components were obtained from taught and untaught data for the various neural networks. Results show that the error trends for untaught data were non-uniform because of the complex nature of the cutting force components, which was caused by different cutting factors and nonlinear characteristics coming into play. However, trends for taught data showed a very good coincidence.

• Industrial Engineering and Management Systems
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• v.11 no.3
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• pp.224-232
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• 2012

The paper proposes a non-parametric methodology, data envelopment analysis, for measuring efficiency and productivity in service delivery systems with capacity constraints. The methodology provides allocation approaches for studying behaviors of firm and customers in service delivery strategy. The experimental study is carried out to investigate allocation behaviors and conduct an objective tradeoff between efficiency approach and productivity approach. The experimental result indicates that the efficiency approach allocates resource via maximizing customer efficiency rather than firm productivity as in the productivity approach. Moreover, the experiment reveals that there exists an objective tradeoff between the efficiency approach and the productivity approach. These findings provide strategic options for allocation policy in service delivery systems.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2011.05a
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• pp.75-76
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• 2011

Hot-rolled steel plates of SPHC and SS400 were oxidized at 600, 750 and $900^{\circ}C$ for 2hr in air. With an increase in oxidation temperature, their oxidation rates increased, being accompanied with formation of pores and cracks in the thickened oxide scales that were non-adherent. The SPHC steels that were manufactured by either the arc furnace or the blast furnace displayed similar oxidation rates, indicating that their oxidation rates were insensitive to the manufacturing processes. The medium-carbon SS400 steel displayed a little faster oxidation rates than the low-carbon SS400 steel, indicating that the carbon content did not significantly influence the oxidation rates.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.2
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• pp.84-91
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• 1997

This paper reports the effort for developing this new Unified Manufacturing Instruction Set and its environment, called here UniSet, to deal with difficulties in set up and operation of Flexible Manufacturing Cells, UniSet has been developed as a non-exclusive unified manufacturing instruction set based on com- parisons of the prevailing machine tool and programming primitives. UniSet allows programmers to deal with only one instruction set, if they so desire, in a single coherent enviroment, rather than numerous machine programming languges. The software system is coded in an Object-Oriented Programming (OOP) language, Smalltalk, and derives its paradigm from the OO philosophy. Test results are also includ- ed to demonstrate the applicability of the approach employed.