• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.05a
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• pp.99-104
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• 2003

This study investigated the yearly variation of pollutant loads outflowing from six watershed of Yeong-il Bay and compared the relationship of pollutant load and water quality, and estimated the Inner productivity of Yeong-Il Bay by using ${\Delta}COD$ method which analysis nonlinear process of water quality. As the estimated results for the pollutant loads of Yeong-Il Bay, total COD load outflowing from Hyeong-san river in flood season(summer) of 2001 year was 2275.0 kg/hr and in dry(low water) season(winter) 852.8 kg/hr, respectively. Load quantity in flood season was about 2.67 times than that in dry season. And as the calculated results of the net-flux of water for seven divisions, it showed that the net-flux of water increased for the divisions of the north coast and inner sea of Yeong-Il Bay but decreased for the south coast. On the contrary, for the cases which water quantity increase from land, the net-flux of water in estuary front of Hyeong-san river decreased but outflowing quantity of that though division of the south coast of Homi-got increased. Finally, this study compared the Inner productions for flood and dry season of Yeong-il Bay by using ${\Delta}COD$ method.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.2
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• pp.149-155
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• 2016

The purpose of this study is to develop special tools used to extend the tool life for the boom of heavy equipment. The boom of heavy equipment is manufactured by cutting the inner and outer surface with respect to the assembly site essential. In particular, when cutting the inner surface, entry of the tool is difficult owing to the limited size of the inner diameter and non circular cutting. In addition, the productivity is poor because the use of the cutting tool made of the SKH material. Therefore, it is necessary to develop a special tool for machining heavy equipment boom to extend tool life and to improve productivity. The special tool developed this study has the form of a holder and tip. The tip was created by applying a commercially available tungsten carbide insert.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.320-323
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• 2002

This paper discusses process design of cold forging for inner tooth part, drum clutch. In respect to high productivity, low material consumption and low piece production costs, Metal forming has more merits than machining process. Net shape forming is huh technology which satisfies merits of metal forming and achieves high accuracy. Recently, net shape forming method widely applied because of high productivity, low material consumption and low piece production costs using press. In this study, the method which accuracy of drum clutch, automatic transmission pin, can be improved is discussed. First, process variables for process design of drum clutch are selected, and then process design is accomplished using forming analysis method. from forming analysis, forming load, stress, unfiling part is obtained. and comparing these results, optimal process design can be determined.

• Journal of Welding and Joining
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• v.23 no.6
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• pp.49-54
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• 2005

Inner Structured and Bonded(ISB) panel, a kind of metallic sandwich panel, consists of two thin skin plates bonded to a micro-patterned inner structure. Its overall thickness is $1\~3mm$and it has attractive properties such as ultra-lightweight, high efficiency in stiffness-to-weight and strength-to-weight ratio. In many previous studies, resistance welding, brazing and adhesive bonding are studied for joining the panel. However these methods did not consider productivity, but focused on structural characteristics of joined panels, so that the joining process is very complicated and expensive. In this paper, a new joining process with resistance welding is developed. Curved surface electrodes are used to consider the productivity and the stopper is used between electrodes during welding time to maintain the shape of inner structure. Welding time, gap of electrodes and distance between welding points are selected as the process parameters. By measuring the tensile load with respect to the variation of welding time and gap of electrodes, proper welding conditions are studied. Welding time is proper between 1.5-2.5cycle. If welding time is too long, then inner structures are damaged by overheating. Gap of electrode should be shorter than threshold value fur joint strength, when total thickness of inner structure and skin plate is 3.3mm, the threshold distance is 3.0mm.

• Health Policy and Management
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• v.23 no.1
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• pp.78-89
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• 2013

This study empirically analyze efficiency and productivity changes of public hospitals of Korea using data envelopment analysis/Window model and global Malmquist indices model. We use the ten-year data from 2001 to 2010 of 30 regional public hospitals listed database from the Association of Korean Regional Public Hospitals. The main focuses are to reveal whether the technical inefficiency are improved as time goes by, and efficiency and productivity are affected by environmental factors. The results can be summarized as follows. First, the efficiencies of public hospitals rise in trend as time passes. Second, regional public hospitals show the different average efficiencies according to their regional type, hospital type, operational type, medicaid type, and demand and supply conditions by Mann-Whitney U-tests. Third, technical efficiency changes mainly contribute to 4.4% annual average growth rate of productivity of regional public hospitals during that period. Our findings have some policy implications. It is confirmed that there exist some environmental inefficiencies, and those inefficiencies can not be overcome through just improving the inner management system. Thus, policy and institutional changes are necessary for regional public hospitals to improve efficiency and productivity overall.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.363-368
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• 2002

An automobile hub is composed of a hollow cylindrical part with inner and outer diameters. These hub diameters must be precise, as any irregularities in them (diameters) can influence/degrade the motion of an automobile with this problem. Highly accurate and reliable hub inner and outer diameters measurement systems are therefore required for inspection of the diameters. In this research, an automobile hub inner and outer diameters measurement system has been developed and tested. The system consists of measuring heads with LVDT sensors, and associated software for automatic measurement and calibration of the diameters and the sensors respectively. The system has been evaluated in comparison with an existing measurement system, and the following outcomes have been achieved; .Improved and guaranteed quality and reliability .Increased productivity and cost reduction. These results prove the system developed in this research to be suitable for automobile hub inspection.

• Design & Manufacturing
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• v.6 no.2
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• pp.79-83
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• 2012

Inner part is used as an insulator in wire fuses. After injection molding, inner part has been showed flashes, filling defects and deformation. After production, operators have to cut off flashes, one by one. this process leads to continuous low productivity and loss of source materials. This study focuses on identifying the causes for flashes, filling defects, clamping force of injectors, mold adhesion, resin of liquidity and others, and on resolving those issues.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.1
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• pp.49-55
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• 2022

Recently, the automobile industry has continued to demand lighter materials owing to international environmental regulations and increased convenience. To address this demand, aluminum parts have increased in popularity and are mainly developed and produced through hot forging and cold pressing. However, because this method has low yield and low production efficiency, a new manufacturing method is desirable. In this study, the water capacity efficiency of an aluminum inner tie rod socket was investigated using cold forging that provided a high yield and excellent production efficiency. Mechanical properties were derived through tensile testing of 6110A aluminum materials, and critical fracture factor and process analysis based on experimental data were carried out. The optimized process was applied as a prototype using cold multi-stage forging, and based on the derived results, the formability, productivity, and material efficiency of aluminum inner tie rod socket parts using this cold forging process was verified.

• Journal of Convergence for Information Technology
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• v.12 no.5
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• pp.278-289
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• 2022

This study empirically analyzed the effect of work value of beauty industry workers on service productivity through job satisfaction. First, according to the result of investigating factors that make effect on service productivity, it was identified that service productivity increases when work value and job satisfaction are higher. Also, it was identified that service productivity increases when awareness of satisfying values, intrinsic satisfaction, recognition of work value, recognition of self-value, and extrinsic satisfaction are higher. Fourthly, as a result of investigating the effects of work value of beauty industry workers on service improvement through job satisfaction, it was identified that the mediating effect of job satisfaction was also significant in the sobel test as Z value of |Z|=15.057 showed a greater value than 1.96. Based on the results of this study, it is expected that inner motivation can be increased for beauty industry workers to recognize that their work is meaningful and worthwhile and service productivity can be maximized by improving the satisfaction and intrinsic job satisfaction that come from work itself.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3376-3382
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• 2014

The system developed inspects automatically defects existing on an inner surface of anodically treated aluminum cylinder-tubes. This system consists of automatic inspection software, and electronic endoscope and a conveyor moving device. By applying the optimal brightness conditions to searching for various defects on the inner surface of cylinder tube, the recognition rate of major defects, such as scratch, oxide and weld line reached 99%. If the present visual inspection process is replaced with the automatic defects inspection system, the physical fatigue of the operator could be reduced and the productivity could be increased. The automatic inspection system developed could also improve the quality of the products.