• Journal of Electrical Engineering and Technology
• /
• v.10 no.3
• /
• pp.1015-1024
• /
• 2015

This paper introduces a low cost, high efficiency, high performance three-phase unified power quality conditioner (UPQC) by using four-switch three-phase inverters (FSTPIs) and an extra capacitor in the shunt active power filter (APF) side of the UPQC. In the proposed UPQC, both shunt and series APFs are developed by using FSTPIs so that the number of switching devices is reduced from twelve to eight devices. In addition, by inserting an additional capacitor in series with the shunt APF, the DC-link voltage in the proposed UPQC can also be greatly reduced. As a result, the system cost and power loss of the proposed UPQC is significantly minimized thanks to the use of a smaller number of power switches with a lower rating voltage without degrading the compensation performance of the UPQC. Design of passive components for the proposed UPQC to achieve a good performance is presented in detail. In addition, comparisons on power loss, overall system efficiency, compensation performance between the proposed UPQC and the traditional one are also determined in this paper. Simulation and experimental studies are performed to verify the validity of the proposed topology.

• New & Renewable Energy
• /
• v.2 no.4 s.8
• /
• pp.86-92
• /
• 2006

This paper analyses the economics of 50kW PV system installed in Tibet and using domestic technology. We show that this system can be expanded to very large-scale photovoltaic power generation [VLS-PV] system successfully. Based on this result, we conduct the economic analysis of 100MW VLS-PV system designed assuming that it will be installed from 2008 to 2017 in Tibet. In this analysis, future price of PV module and system are estimated based on the methodology of experience curve. In 50kW PV system, the generation cost is calculated at 567.2 won/kWh and this is lower than the one of domestic PV system. In future 100MW VLS-PV system. the generation cost is calculated at 305.4 won/kWh by declining system price. If the lifetime and efficiency of the system goes up, due to future technological improvements, the generation cost can be lowered. Moreover, under the environmental and political effect, VLS-PV system can be as competitive as the conventional energy within 20 years.

• Journal of the Society of Naval Architects of Korea
• /
• v.57 no.3
• /
• pp.152-159
• /
• 2020

Ship owners had pursued higher benefits by demanding the new design and construction of ships with higher operational efficiency. There was a necessity for shipyards to suggest a more economical design and advanced operation concept in order to meet the demands. Especially, since BOG combustion and activation of the re-liquefaction unit had to be taken into account in ship design in addition to fuel oil and gas consumption, the evaluation of the operating efficiency considering the technological trends was necessary. In this paper, it was aimed to study the design philosophy and operation strategy by considering the effect of fuel oil and gas consumption, BOG combustion, and activation of the re-liquefaction unit on the operating cost for laden voyage according to ship speed, BOR, and activation of the re-liquefaction unit. For this purpose, the costs were acquired by conducting the sailing simulation of an LNGC based on a mathematical model including the maneuvering equations of motion. The design philosophy and operation strategy was reviewed in terms of the operating cost.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.19 no.1
• /
• pp.19-26
• /
• 2001

The Organizations working with technological projects will be more and more common to connect consultants. Those who shall carry out the pre-analysis of the projects ought to have a professional knowledge to the area about economical methods with information technology and changed technology of surveying and mapping. New surveying and mapping methods, such as TotalStation, GPS, orthophoto, digital map, and satellite remote sensing, have totally changed the old concept of surveying. Also the technology for the new mapping has greatly changed from analog to analytical to digital during the past 50 years. Now, the proper choice of surveying and mapping methods becomes a decision on cost and efficiency rather than the use of a particular technology. As an example, GPS equipment dose cost considerably more than traditional surveying equipment, but the advantages it provides make it very cost-effective. In this study, the cost and benefit factors of the surveying and mapping projects are evaluated independently and benefit/cost ratio(B/C ratio) is used in benefit-cost evaluation of the different surveying methods. The benefit-cost model of surveying and mapping methods will produce economical result in the whole projects.

• 한국신재생에너지학회:학술대회논문집
• /
• 2005.06a
• /
• pp.656-659
• /
• 2005

his paper develops the systematic and quantitative priority-determining method for national investment using the framework of evaluating R&D. This study proposes multi criteria for evaluating the R&D of New & Renewable Energy through analysing the attribute of 11 types of energy. The framework is constituted by 4 criteria, the political urgency, economic impact, regional constraint. and technological attribute and the each criteria has 3 or 4 sub-criteria. These sub-criteria are weighted using AHP.

• Journal of Korean Institute of Industrial Engineers
• /
• v.4 no.2
• /
• pp.67-75
• /
• 1978

This paper attempts to identify the factors which are directly related to the effective transfer of technology from developed countries to LDCs. The recipient countries should have the capability of alteration/adaptation based on cost-minimization criteria. Some problems are such that technologies are transferred on the conditions of MNFs, packaged forms and under state management which result in lack of competitive pressure. Non-technological criteria are shown to be a problem under state management in the transaction of technology.

• Proceedings of the KSR Conference
• /
• 2003.10b
• /
• pp.354-359
• /
• 2003

The purpose of this study is to establish the technical system of national logistics standardization and to strengthen the national competitiveness through reduction of the logistic cost We review of the government and private roles in the logistic sectors and suggest plans for the improvement of logistics standardization for its completion in the unit load system in Korea. We conclude that a symmetrical logistics standardization may accomplish to reduce the costs of national logistics.

• 제어로봇시스템학회:학술대회논문집
• /
• 1986.10a
• /
• pp.437-442
• /
• 1986

Survey has been made to evaluate technological level and to identify research issues in CAD/CAM area. It is found out that major users of the CAD/CAM system are in mechanical and electronics as well as garment industries. Their experience shows that the impact of the CAD/CAM introduction is not yet noticeable in drafting man power and cost reduction. It is identified that the low penetration rate of CAD/CAM technology in industry is due to the lack of locally developed CAD/CAM softwares.

• Proceedings of the KIEE Conference
• /
• 2003.07a
• /
• pp.71-73
• /
• 2003

The paper discussed for energy saving technology of electric arc furnace (EAF) in steel making industry. The energy of EAF in steel making process is nearly 10% of total manufacturing cost. This paper is shown new trand of energy saving technology and future study analysis of technological evolution of the EAF by 2010 issued IISI.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.17 no.30
• /
• pp.51-57
• /
• 1994

This paper considers the problem of equipment replacement A equipment replacement problem is treated in a thchnological development environment. Our model assumes that the costs associated with the presently available thchnology and future technology is known, but the appearance times of future technology is uncertain. A cost model is presented, and method is suggested for finding the optimal operating time for replacement A numerical example is shown.