• Journal of Mechanical Science and Technology
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• v.17 no.4
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• pp.521-527
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• 2003

Modern automatic transmissions equip torque converters with lock-up clutches to reduce the energy loss of hydraulic systems. Instead of simply engaging the clutch disks, the new technology of clutch slip has been developed to improve the overall efficiency of power transmission. There are two major problems with the clutch slip system. The first is how to keep the slip between the two disks within a small range and the second is when to start or stop the slip. In this paper, the second problem is discussed in view of the vehicle economy. With a simple vehicle dynamic model, the fuel economy is calculated to determine the lock-up strategy. Then the lock-up strategy is developed for a slip schedule.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.452-455
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• 2005

We have studied the prearranged plan and the economy of a candidate site for the development of small hydro power. And also we have confirmed its economy by suggesting the technology of the unmanned operation and the selection of the water turbine generator which has a great efficiency. working rate and suitability to the topographical characteristics of various development sites, for example, irrigation reservoirs, water works pipes, sewage systems and cool ing water of a steam power stat ion. Besides we give more examples of the select ion of Francis, propeller turbine and induction generator which can achieve a maximum of power production at a minimum construction cost. With a water turbine which runs at the low head we are able to suggest many programs to boost a development of small hydro power more economically.

• Journal of Technology Innovation
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• v.15 no.2
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• pp.1-24
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• 2007

In this study, we estimated a CES production function for the Korean economy. We have found in the empirical results that the elasticity of the factor substitution is less than one and that the Korean economy exhibits labor-saving technological progress. In addition, we obtained the regression coefficient of R&D investment on technological change, i.e., the elasticity of R&D investment with respect to the technological change was 0.26% point. It implies that if R&D stock increases by 1%, labor efficiency increases 0.26% point through technological progress which is Hicksian non-neutral. It confirms that innovation-based growth strategy by increasing R&D investment would be effective on the one hand. Some policy consideration on the other might be needed for an increase in employment which is offset by technological progress.

• Journal of Environmental Policy
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• v.2 no.2
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• pp.81-103
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• 2003

This paper compares the environmental economic performance of the South Korean and the German economy during the last decade. The analysis is based on comparable data from the Environmental Economic Accounts (EEA). The EEA is a satellite account to the National Accounts which enhances the conventional economic accounts by a description of the interactions between the economy and the environment. The data from the EEA and the national accounts are fully compatible. In absolute terms the environmental pressures caused by economic activities were with regards to the environmental factors used for the analysis generally lower in South Korea than in Germany. If the use of environmental factors is related to each country's gross domestic product (environmental productivities) a lower level of environmental productivity can be observed for most of the environmental factors in South Korea compared to Germany. For example in 1999 energy and $CO_2$ productivity were about two fifths of the German level. This corresponds to the relation regarding labour productivity (Gross domestic product per employment).

• International Journal of Automotive Technology
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• v.8 no.6
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• pp.675-685
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• 2007

A single cylinder SI engine with a VVA system is modeled by the coupling of a commercial 1D simulation package and an additional combustion model and validated by comparison with experimental data. A number of simulations are carried out to investigate the effects of five different VVA systems on the performance and fuel efficiency of the baseline engine. Finally, the simulation model is applied to an extensive computational study to map out the strategies to operate the engines with dual CVVT and dual CVVT-2 step VVL systems in a fuel-efficient manner.

• Journal of the Korean Regional Science Association
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• v.10 no.2
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• pp.45-51
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• 1994

The purpose of this paper is to present the optimal investment conditions of SOC facilities for maximizing regional social welfare in implementing the urban development project in the theoretical fashion. Particularily, SOC facilities are divided into both supply-side($P_s$) and demand-side SOC ($P_d$) in the paper. General equilibrium analysis from the intra-regional viewpoint by utilizing Pareto's Optimal Conditions and by revising Samuleson's Conditions for public goods($P_s$ and $P_d$) results in the optimum pattern of SOC investment. The following are important implications from the analysis. First, rather than the pursue social equity, SOC investment is to resolve the issue of efficiency to activate the regional economy. Second, the marginal rate of transformation (MRT) between $P_s$ and $P_d$ in the region is to play a significant role in structuring SOC investment plant of local government for social welfare maximization. Third, the optimal SOC investment policy based on this regional economy but also to generate the enhancement of soical amenities of the residents.

• Asian Journal of Business Environment
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• v.5 no.2
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• pp.31-36
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• 2015

Purpose - This work aims to study the existing management process and methods of statistical evaluation of personnel mobility management, and propose improvement measures. This is particularly relevant in today's market economy because proper organization of personnel movement affects the availability and effective utilization of human resources in enterprises. Hence, it influences the volume, timely execution of work, equipment efficiency, and consequently the volume of production, its cost, profit, and other economic indicators. Research design, data, and methodology - We investigate the indicators that measure staff mobility, and their dependent consequences. Further, it analyses the factors influencing high staff turnover, which is a main indicator of staff mobility. Results - Measures for staff mobility development and prevention of turnover are proposed. Micom Systems is a sample case that has developed special programs to reduce staff turnover. Conclusions - Staff mobility leads to additional costs, significant loss of working time, and increase in defects. However, the advantages of staff mobility outweigh these negative factors. The role of staff mobility in a market economy cannot be overestimated.

• Journal of Korean Society for Atmospheric Environment
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• v.15 no.3
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• pp.317-325
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• 1999

The demand of diesel engine on the construction equipment has been rapidly increased because of high thermal efficiency and fuel economy. The exhaust emission from nonroad vehicles equipped with diesel engine such as construction equipment, ship, and agricultural equipment, etc. Which are known to be harmful to human health and environment, has not been regulated in our country. But the regulation for nonroad vehicle has been already progressed in advanced country. So we investigated the contribution ratio of air pollution by construction equipment in order to establish the exhaust emission management strategy for nonroad vehicle. Based on the statistical data for construction equipment, 5 kinds of equipment are selected and tested in the engine dynamometer to determine the emission factor. And the amount of air pollutant from construction equipment are calculated by using of the emission factor and recommended exhaust emission standard for construction equipment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.957-960
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• 2013

Eco driving comprises the use of feedback information that informs the driver of vehicle performance. This paper evaluated the performance of feedback device that reported instantaneous fuel economy to drivers while driving. We took the measurement by getting data through OBD port from commercial vehicle covered 67 km on road. The changes observed in fuel efficiency were established 10.6 % improvement in fuel economy.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.735-741
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• 2005

We have studied the prearranged plan and the economy of a candidate site for the development of small hydro power. And also we have confirmed its economy by suggesting the technology of the unmanned operation and the selection of the water turbine generator which has a great efficiency, working rate and suitability to the topographical characteristics of various development sites, for example, irrigation reservoirs, water works pipes, sewage systems and cooling water of a steam power station. We proposed some opinions such as the better improvement of small hydropower industry the people' view, cooperation among industry/university/ research institutes, remote control/maintenance and goverment's legislature and supporting system etc.