• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.5
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• pp.23-29
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• 2001

This paper is the second of companion papers, which investigate port-masking effects on emission and fuel economy. Port-masking was applied to commercial SOHC 3-valve engine by inserting masking plates between manifold and port. To induce various conditions of stratification, six types of masking plates were applied. In this paper, main interest is focused on the influence of injection timing on emission and fuel economy. Various injection timing was applied to the six cases, under the stoichiometric and lean-limit air-fuel ratio. Under the stoichiometric condition, an explanation about the reason of the change in emission level due to injection timing change is given. It is observed that NOx emission under the LML condition varies significantly when the injection timing changes.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.6
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• pp.30-36
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• 2003

Variable valve timing(VVT) mechanisms are used widely for improving fuel consumption and reducing emissions. Most of application, however, are limited in the DOHC engine. Dual equal retard/advance strategy is relatively simple one and can be applied to both SOHC and DOHC engines. In this study, effects of dual equal valve timing retard/advance are investigated to observe the feasibility of VVT system on an SOHC SI engine. The result shows that fuel economy and emissions are improved in the dual retard condition due to increased internal EGR. Some amount of increase in volumetric efficiency can be achieved by advancing valve timing at low speed and by retarding at high speed. In this case, however, full load power is not so much improved as the volumetric efficiency increases because of severe knock. In the dual advance condition, there is no merit in the fuel economy and emission.

• The Korean Journal of Applied Statistics
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• v.8 no.2
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• pp.43-54
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• 1995

The fishery household economy survey is a sample survey which produce estimates on the fishery household economy and fishery management in Korea. We propose a sample design for this survey. This design is developed based on results of 1990 fishery census and Shi-Do is assumed to be subpopulation for Shi-Do estimates. Samples are selected by stratified two-stage cluster sampling in Shi-Do and income function is found for stratification. Fishery household income is estimated by a linear estimator.

• Korean Journal of Organic Agriculture
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• v.12 no.1
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• pp.67-80
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• 2004

Farm economy is getting worse because of the free trade trends in agriculture sector and unreasonable application of market economy principles to agricultural products. And The worldwide issues of environmental pollution as well as want of food, water and energy make human future be anxious. In addition, consumers raise questions in argument about safety of foods produced by traditional farming or imported. So I propose the urban-rural living community movement(URLCM) as an alternative plan for sustainable domestic agriculture. URLCM based on environmentally friendly agriculture and community consciousness will be able to solve many of present issues on agriculture and rural society through incessant interchanges between urban and rural community. This URLCM has to be basically founded on principles of symbiosis-coexistence and life circulation. So those that have to be driven forward arc organizing producers and consumer cooperatives, making environmentally friendly rural region and products, combining with consumer cooperatives, training the participants and so forth.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.10a
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• pp.302-305
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• 2000

The operation of a networked computing system (NCS), such as Internet, can be viewed as a resource allocation problem, and can be analyzed using the techniques of mathematical modeling. We define a general NCS and translate that setup into a model of an economy. The preferences of users are taken as primitives, and servers in the network are viewed as productive firms with priority input queues. Each sewer charges a rental price for its services by priority class. We characterize optimal system allocation, and derive formulae for supporting rental prices and priority premia such that the aggregated individual user demands do not exceed optimal levels and waiting-time expectations are correct. Our economic approach has the added benefit of providing a sound basis for evaluating NCS investment alternatives, using a process analogous to free entry and exit in free-enterprise economies.

• Journal of Korean Institute of Industrial Engineers
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• v.8 no.1
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• pp.40-60
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• 1982

Since the first oil embargo (1973), there have been developed many different types of energy-economy interaction models based upon various aspects of energy impact mechanism. We will propose to develop an integrated energy-economy interaction analysis system for less developed countries' energy policy analysis, especially for investment analysis toward constructing energy-saving industry infrastructure ; which is based on the motivation of combined energy models by John P. Weyant. This modeling system can cover the economic growth, inter-industry transactions including production features, and process analysis of energy sector in the total network scheme of general equilibrium, so that it can give many political implications as well as the modeling concept to be used for analyzing various political issues and making decisions related to national energy environment.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.11a
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• pp.33.2-42
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• 2000

This study probes the necessity of establishing a logistic free zone in Port of Busan. It considers the economic effects of establishing the logistic free zone of Busan Port, and suggests policy prescriptions for introducing the free zone system and improving the logistics functions of Busan Port. Using input-output table data, the regression analysis was able to provide a quantitative prediction on effects of making the Busan Port a tariff-free zone. Influence for the regional economy due to the enforcement of the free zone system this research found that a strong positive effects should be expected on the Busan regional economy once the logistic free zone would be set up at the Port of Busan. The positive economic effects on Busan regional industries might be further strengthened if the value-added logistics function of Busan Port could be supplemented by linking to the hinterland of Busan Port.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.11
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• pp.2817-2824
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• 1994

A torque split type multi-pass CVT(MPC) system consiting of CVT and planetary gear train with 4 clutches was suggested to overcome the inherent inferior acceleration performance of CVT. Also, a shifting algorithm of MPC was suggested for the two driving modes : (1) power mode and (2) economy mode. By using the shifting algorithm and the MPC vehicle dynamic model, numerical simulations were performed to estimate the performance of the MPC vehicle. Simulation results showed that comparing the performance of the conventional 4-speed automatic transmission, an improvement in acceleration can be obtained by MPC for the power mode and 31% improvement in fuel economy for the economy mode.

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.3
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• pp.73-86
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• 2018

An analysis of Airbnb and Kozaza will show how valuable and rare resource can have an impact on company performances. Airbnb applied the sharing economy platform, and this business model had disrupted the hospitality industry. Thus, this paper will investigate a Korean company called Kozaza which had benchmarked Airbnb. Furthermore, it will apply the theory of VRIO framework, which consists of how valuable, rare, costly to imitate (imitability), and organization (exploited by the organization) to find competitiveness of Kozaza in the hospitality industry. Thus, it will attempt to show that Kozaza's business model of utilizing the unused resource of Hanok (traditional Korean house) and partnerships with Hanokstay, Seoul Metropolitan Government and Soul Tourism Organization and others have enhanced their resource and capability to strengthen their business model. Furthermore, this research will explore how Kozaza can competitively be successful in the future.

• Journal of Korean Society of Rural Planning
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• v.5 no.1 s.9
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• pp.12-19
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• 1999

This study proposes the following directions on the basis of results gained from a survey in Yamanasihyun Kawaguchikocho, where the herb festival is successfully held, in order to activate the local economy by herb. 1) The herb education for person in charge in the local authorities, the promoter of herb festival, has to be preceded and the local residents should try to understand what the herb is. 2) For a successful herb festival in the aspect of local economy and environmental conservation, detailed basic study and publicity including human -, natural environment, ecological conditions for herb should be peformed. 3) Herb event should have various programs and formats to arouse the user's interest and should be a place for environmental education.