• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.49
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• pp.11-21
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• 1999

The purpose of this study is to present the method to select optimal size for the industrial products which are closely related to human's body size. For this purpose, human factors such as body characteristics, body features, and preference in product selection which needs to be considered in setting standards were analyzed. This analysis is to select optimal size to minimize losses caused by the difference of size between demand by the customers and supply from the manufacturers. Using loss function, repetitive calculation process algorithm by using bisearch method was applied in selecting the sizes of demand and supply which minimize the total expected losses. For cumulative normal distribution probability, IMSL routine DNORDF was used. In case study, comparison has been made between the result which was calculated using presented algorithm and the results calculated by the process currently used by KS and ISO by measuring aged women's body size in human factors side and sorting them through the factor analysis and cluster analysis for feature factor extraction. Thus, they can be used as a basis for establishing industrial product standards.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.2
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• pp.18-26
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• 2012

Though electricity consumption amount in industry has been increased gradually, corresponding power supply show symptoms of marginal point. Importance of demand-side management from large-industries has also been raised. This paper deals with induction motor, which is one of representative examples of heavy electricity consumption utilities, to analyze potential technical capability, economic feasibility from consumers' viewpoint and demand-side management feasibility from nation-wide perspective. Nation-wide economic feasibility analysis was done through California test, which has been used as demand-side management evaluation model. This paper also describes limitation of existing high efficiency induction motor in terms of contribution to demand-side management and utilizes premium motor to calculate demand-side management contribution level and economic feasibility evaluation. Likewise, this paper emphasizes the efficiency improvement of induction motor and analyzes how much premium motor related technologies can contribute to demand-side management.

• Safety and Health at Work
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• v.10 no.1
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• pp.61-66
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• 2019

Background: Emergency workers such as firefighters are cataloged within the most demanding and injurious professions globally. Considering the health and safety implications in firefighting, a lot of research needs to be conducted to examine how firefighters' task characteristics and their work demand influence the development of work-related musculoskeletal disorders (WMSDs). This study therefore examines how the task characteristics of firefighters moderates the relationship between their work demand and the development of WMSDs. Methods: Convenient sampling was employed to select 320 firefighters in the Greater Accra region of Ghana. Data were analyzed using descriptive statistics, correlation, and regression. Results: The findings revealed that work demand and task characteristics have significant positive effects on WMSDs. Again, the task characteristics of firefighters moderates the relationship between their work demand and WMSDs. Conclusion: Since the study shows that task characteristics influences the relationship between work demand and WMSDs, it is vital for managers to constantly modify the nature of tasks performed by and work demand of emergency workers to minimize the development of WMSDs and other industrial health complications.

• Journal of Labour Economics
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• v.35 no.1
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• pp.55-88
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• 2012

This article investigates the patterns of workforce aging in each industry, and examines how changing industrial structure affected the labor-market demand for and employment security of older workers in Korea. The relative size of the industries that are major employers of older workers has relatively declined since 2001, resulting in a decrease in labor-market demand for aged persons. Changes in industrial structure that occurred during the last decade have also brought an overall deterioration in the extent of employment security of older workers. These results suggest that the economic environment surrounding policies aimed at encouraging the employment of older workers is not entirely favorable. This paper also points out that policy makers need to consider that employment conditions of older workers are highly heterogenous across industries.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.2
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• pp.1-12
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• 2009

Distribution centers in a distribution system that consists of the distribution centers and retailers supplies products to retailers. At the present, although total capacity of the distribution centers are enough to supply total demand of retailers, capacity of the distribution centers need to be expanded to satisfy the demand of retailers in case that future demand of the retailers will be increased. Capacity expansion model in a distribution system is to determine the location and size of expansion distribution centers that minimize costs among given distribution centers. Transportation amount from distribution center to retailers also is determined. The costs factors are the capacity expansion costs of the distribution centers and the transportation costs from the distribution centers to the retailers. A model is formulated, and a genetic algorithm based solution procedure is developed. A numerical example is shown and the algorithm is analyzed through examples.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.4
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• pp.63-71
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• 2014

As power consumption increases, more power utilities are required to satisfy the demand and consequently results in tremendous cost to build the utilities. Another issue in construction of power utilities to meet the peak demand is an inefficiency caused by surplus power during non-peak time. Therefore, most power company considers power demand management with time-based electricity rate policy which applies different rate over time. This paper considers an optimal machine operation problem under the time-based electricity rates. In TOC (Theory of Constraints), the production capacities of all machines are limited to one of the bottleneck machine to minimize the WIP (work in process). In the situation, other machines except the bottleneck are able to stop their operations without any throughput loss of the whole manufacturing line for saving power utility cost. To consider this problem three integer programming models are introduced. The three models include (1) line shutdown, (2) block shutdown, and (3) individual machine shutdown. We demonstrate the effectiveness of the proposed IP models through diverse experiments, by comparing with a TOC-based machine operation planning considered as a current model.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.86-88
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• 2003

New cities and industrial complexes are being developed actively according to the government's policy. To determine the size of investment, number of power lines and substations for stable power supply to newly developed industrial complexes, the accurate estimation of power demand is necessary. "The standards for the estimation of power demands in newly developed residential and industrial complexes" established by KEPCO in 1991 have been used up to now. But the background for the estimation of power demands is weak and the accuracy has not been verified. Also, it has been passed above 10 years since their establishment and the social & economic situations have changed a lot, which requires an urgent revision. Through this survey and analysis of existing areas, new standards that will enable more accurate estimation of power demands in new cities and industrial complexes to be developed in the future are established by calculating the some kinds of power demand factors.

• Journal of Industrial Technology
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• v.18
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• pp.425-430
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• 1998

The Asan Bay area Korea is situated in an unbalance or water supply and demand relating to the Ansung, Sapkyo, Dangjin and Youmwha rivers and their estuary reservoirs. The multi-reservoir operation was studied by the Hierarchical Operation Model for Multi-reservoir System(HOMMS) assuming that these four estuary reservoirs were linked to each other in order. The result of this study shows that storage capacity deficiency in 2011 was estimated as 8 MCM in the Sapkyo and 31 MCMin Dae Ho estuary reservoir, respectively. In case of linking four reservoirs, the water deficiency will not occurs in all the reservoirs even if additional agricultural water of 78 MCM/yr was supplied. Total additional water demand for agricultural, municipal and industrial uses was estimated as 321.9 MCM/yr while additional supply by linking the reservoirs was estimated as 160.4 MCM/yr. 50% of additional demand. The remaining 161.5MCM/yr would be supplied transferring other watershed.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.1
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• pp.129-136
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• 2019

In this study, we proposed a model for forecasting power energy demand by investigating how outside temperature at a given time affected power consumption and. To this end, we analyzed the time series of power consumption in terms of the power spectrum and found the periodicities of one day and one week. With these periodicities, we investigated two time series of temperature and power consumption, and found, for a given hour, an approximate linear relation between temperature and power consumption. We adopted an exponential smoothing model to examine the effect of the linearity in forecasting the power demand. In particular, we adjusted the exponential smoothing model by using the variation of power consumption due to temperature change. In this way, the proposed model became a mixture of a time series model and a regression model. We demonstrated that the adjusted model outperformed the exponential smoothing model alone in terms of the mean relative percentage error and the root mean square error in the range of 3%~8% and 4kWh~27kWh, respectively. The results of this study can be used to the energy management system in terms of the effective control of the cross usage of the electric energy together with the outside temperature.

• Journal of Korean Institute of Industrial Engineers
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• v.20 no.3
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• pp.55-63
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• 1994

Optional two-part tariffs are in growing use in telecommunication services markets. This paper considers the problem of designing profit-maximizing optional two-part tariffs for heterogeneous user groups. It is shown that, at an optimum, one of usage charges among a set of optional two-part tariffs should be made equal to marginal cost. It is also shown that, if demand curves cross, then one of usage charges at the optimum can be below marginal cost. An example with linear demand functions is given to illustrate the important features of optimal two-part tariffs.