• Title/Summary/Keyword: allowable strategy

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Economic Analysis Study on the R&D Effect of Performance Improvement of the Tri-generation Fuel Cell System (연료전지 삼중열병합 시스템의 성능개선 R&D 효과에 대한 경제성 분석 연구)

  • Ahn, Jong-Deuk;Lee, Kwan-Young;Seo, Seok-Ho
    • New & Renewable Energy
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    • v.18 no.2
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    • pp.26-39
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    • 2022
  • Considering the recent substantial increase in national research and development (R&D) budgets in the energy sector there has been increased Interest in the effectiveness of government R&D investments. We conducted a case study to calculate the allowable scale and effectiveness of R&D investment by calculating the direct performance improvement effect resulting from R&D investment as an economic value. Using conditions that existed prior to R&D investments as a reference, five cases in which performance improved due to R&D investments were compared and analyzed. The government's financial investment is increasing rapidly in line with the establishment of the national hydrogen roadmap. R&D is needed to enhance the current low technology readiness level of hydrogen fuel cells compared to solar and wind energy fields. Therefore, an R&D project to improve the performance of the fuel cell system was selected as this case study's subject. Using the results in this study, the allowable level of investment in the task unit of national R&D projects could be calculated. Moreover, it is advisable to provide a standard for rational decision making for new R&D investments since it is possible to determine investment priorities among a large number of candidates.

Thermo-mechanical Design for On-orbit Verification of MEMS based Solid Propellant Thruster Array through STEP Cube Lab Mission

  • Oh, Hyun-Ung;Ha, Heon-Woo;Kim, Taegyu;Lee, Jong-Kwang
    • International Journal of Aeronautical and Space Sciences
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    • v.17 no.4
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    • pp.526-534
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    • 2016
  • A MEMS solid propellant thruster array shall be operated within an allowable range of operating temperatures to avoid ignition failure by incomplete combustion due to a time delay in ignition. The structural safety of the MEMS thruster array under severe on-orbit thermal conditions can also be guaranteed by a suitable thermal control. In this study, we propose a thermal control strategy to perform on-orbit verification of a MEMS thruster module, which is expected to be the primary payload of the STEP Cube Lab mission. The strategy involves, the use of micro-igniters as heaters and temperature sensors for active thermal control because an additional heater cannot be implemented in the current design. In addition, we made efforts to reduce the launch loads transmitted to the MEMS thruster module at the system level structural design. The effectiveness of the proposed thermo-mechanical design strategy has been demonstrated by numerical analysis.

Integrated Traffic Management Strategy on Expressways Using Mainline Metering and Ramp Metering (본선미터링과 램프미터링을 이용한 고속도로 통합교통관리 전략)

  • Jeong, Youngje;Kim, Youngchan;Lee, Seungjun
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.12 no.2
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    • pp.1-11
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    • 2013
  • This research proposed integrated expressway traffic management strategy using ramp metering and toll mainline metering. This research suggested a traffic signal optimization model for integrated operation of ramp and mainline metering based on Demand-Capacity Model that is used to optimize allowable input volume for ramp metering in FREQ model. The objective function of this model is sectional throughput volume maximization, and this model can calculate optimal signal timings for mainline metering and ramp metering. This study conducted an effectiveness analysis of integrated metering strategy using PARAMICS and its API. It targeted Seoul's Outer Ring Expressway between Gimpo and Siheung toll gate. As a simulation result, integrated operation of mainline and ramp metering provided more smooth traffic flow, and throughput volume of mainline increased to 14% in congested section. In addition, a queue of 400 meter was formed at metering point of toll gate. This research checked that integrated traffic management strategy facilitates more efficient traffic operation of mainline and ramp from diffused traffic congestion.

A NEW LOOK AT THE FUNDAMENTAL THEOREM OF ASSET PRICING

  • Yan, Jia-An
    • Journal of the Korean Mathematical Society
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    • v.35 no.3
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    • pp.659-673
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    • 1998
  • In this paper we consider a security market whose asset price process is a vector semimartingale. The market is said to be fair if there exists an equivalent martingale measure for the price process, deflated by a numeraire asset. It is shown that the fairness of a market is invariant under the change of numeraire. As a consequence, we show that the characterization of the fairness of a market is reduced to the case where the deflated price process is bounded. In the latter case a theorem of Kreps (1981) has already solved the problem. By using a theorem of Delbaen and Schachermayer (1994) we obtain an intrinsic characterization of the fairness of a market, which is more intuitive than Kreps' theorem. It is shown that the arbitrage pricing of replicatable contingent claims is independent of the choice of numeraire and equivalent martingale measure. A sufficient condition for the fairness of a market, modeled by an Ito process, is given.

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Optimal Design System of Grillage Structure under Constraint of Natural Frequency Based on Genetic Algorithm (고유진동수 제한을 갖는 골조구조의 GA 기반 최적설계 시스템)

  • Kim, Sung Chan;Kim, Byung Joo;Kim, E Dam
    • Journal of the Society of Naval Architects of Korea
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    • v.59 no.1
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    • pp.39-45
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    • 2022
  • Normal strategy of structure optimization procedure has been minimum cost or weight design. Minimum weight design satisfying an allowable stress has been used for the ship and offshore structure, but minimum cost design could be used for the case of high human cost. Natural frequency analysis and forced vibration one have been used for the strength estimation of marine structures. For the case of high precision experiment facilities in marine field, the structure has normally enough margin in allowable stress aspect and sometimes needs high natural frequency of structure to obtain very high precise experiment results. It is not easy to obtain a structure design with high natural frequency, since the natural frequency depend on the stiffness to mass ratio of the structure and increase of structural stiffness ordinary accompanies the increase of mass. It is further difficult at the grillage structure design using the profiles, because the properties of profiles are not continuous but discrete, and resource of profiles are limited at the design of grillage structure. In this paper, the grillage structure design system under the constraint of high natural frequency is introduced. The design system adopted genetic algorithm to realize optimization procedure and can be used at the design of the experimental facilities of marine field such as a towing carriage, PMM, test frame, measuring frame and rotating arm.

New Zealand's Catch Balancing Regime: A Model of Enforcement Strategies (뉴질랜드 어획량 균형 제도: 시행전략모델)

  • Nam, Jongoh;Dobrot, Gabriela
    • Environmental and Resource Economics Review
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    • v.17 no.4
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    • pp.775-812
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    • 2008
  • This paper provides a theoretical approach to the New Zealand's Catch-Balancing Regime (CBR) with a reporting requirement under the Individual Transferable Quota (ITQ) system. The enforcement strategy depicted draws on recent literature regarding practical applications of the Revelation Principle. New Zealand's use of CBR-specific instruments such as deemed values, remains to be improved. However, some of its features can constitute a valuable example for regulators seeking to improve their methods of dealing with issues as bycatch or overfishing in order to maintain Total Allowable Catch (TAC) levels under emerging ITQ systems. The enforcement strategy analyzed has the potential to provide a more sustainable and efficient management of the fish stock, reduce discarding and stabilize monitoring costs, while improving the level of reporting compliance.

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Strategic Prospects of Environmental Restoration of Stream Side in Japan(III) - With a Special Reference to the Forest Road, Forest Conservation and Erosion Control - (일본(日本)에서 계류변(溪流邊)의 환경복원(環境復元) 발전전략(發展戰略)(III) - 임도(林道) 및 치산(治山)·사방(砂防)을 중심(中心)으로 -)

  • Park, Jae-Hyeon;Woo, Bo-Myeong;Lee, Heon-Ho
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.3 no.3
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    • pp.113-125
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    • 2000
  • This study was carried out to introduce current status and development strategy for an environmental restoration of stream side in Japan, and to consider a methodology which could be effectively applied for the environmental restoration of stream side in Korea. The strategy prospects of environmental restoration in Japan were summarized as follows : 1. When we establish the long term erosion control planning, we should make detail planning after considering of a certain block of watershed units. Because most of the disaster is caused by soil movement which was occurred by water contents. 2. Nowadays, the general torrent erosion control planning system in Japan focused on reducing the sediment such as by placement of erosion control facility and by restoration of afforestation, after calculation of several factors including expected amount of sediment, and the different amount of planned sediment and allowable sediment. 3. In the past, the goal of forest conservation and erosion control planing was to fix the amount of soil movement by construction of permanent facilities. While, the goal of forest conservation and erosion control planning in the future needs to change the techniques to a small and middle scale's soil movement which could prevent soil movement from large scale of soil disasters, but allow soil movement effectively. Also, it is considered to change erosion control dams from non passing type to passing type. 4. Restoration of stream-side ecology, erosion control for the conservation of ecology should be planned and conducted cautiously based on concepts of ecology conservation and development of environmentally sound techniques.

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On-orbit Thermal Control of MEMS Based Solid Thruster by Using Micro-igniter (MEMS 기반 고체 추력기의 마이크로 점화기를 이용한 궤도 열제어)

  • Ha, Heon-Woo;Kang, Soo-Jin;Jo, Mun-Shin;Oh, Hyun-Ung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.42 no.9
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    • pp.802-808
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    • 2014
  • MEMS based solid propellant thruster researched for the purpose of an academic research will be verified at space environment through CubeSat program. For this, the temperature of the MEMS thruster should be within allowable operating temperature range by proper thermal control to prevent the ignition failure caused by ignition time delay and to guarantee the structural safety of the MEMS thruster in the low temperature. In this study, we proposed an effective thermal control strategy, that is to use micro-igniter as a heater and temperature sensor for active thermal control instead of using additional heater. The effectiveness of the strategy has been verified through on-orbit thermal analysis of CubeSats with MEMS thruster.

The Effect of Psychological Temptation, Site Quality and Sense of Community upon Online Game (심리적 유인과 사이트 품질, 공동체의식이 온라인게임에 미치는 영향)

  • Lee, Sang-Chul;Kim, Nam-Hee;Moon, Jae-Young;Suh, Young-Ho
    • Asia pacific journal of information systems
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    • v.13 no.4
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    • pp.207-227
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    • 2003
  • The purpose of this research is to identify if psychological temptation, site quality and sense of community influence user's flow and addiction and to identify causalities among flow, addiction, customer satisfaction and customer loyalty in online industry. Many previous researches in the area of online games have been carried out about addiction by psychologist and about the development of related technologies by scientists. There are only a few studies about the customer satisfaction from the online business perspective. However, this research is different from the previous ones in the sense that both flow and addiction are considered in the study of the relationship between customer satisfaction/loyalty and flow/addiction in the area of online industry. The empirical results of high-order factor analysis indicate that six independent variables such as design, information, feedback, impulsiveness and motivation have converge three second-order variables such psychological temptation, site quality and sense of community. Consequently, site quality and sense of community have impacts on the flow, while on the other hand, psychological temptation has impacts on the addiction. Conclusively, customer satisfaction and loyalty are positively related not with the addiction but with the flow. Besides, customer loyalty is significantly influenced by the flow and the customer satisfaction. This indicates that companies in the online game industry have to develop a strategy for the flow which is more socially and ethically allowable than the addiction.

Maximum Torque Control of Induction Motor Drive using Multi-HBPI Controller (다중 HBPI 제어기를 이용한 유도전동기 드라이브의 최대토크 제어)

  • Kang, Sung-Jun;Ko, Jae-Sun;Choi, Jung-Sik;Baek, Jeong-Woo;Jang, Mi-Geum;Kim, Soon-Young;Chung, Dong-Hwa
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2009.10a
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    • pp.363-366
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    • 2009
  • The maximum output torque developed by the machine is dependent on the allowable current rating and maximum voltage that the inverter can supply to the machine. Therefore, to use the inverter capacity fully, it is desirable to use the control scheme considering the voltage and current limit condition, which can yield the maximum torque per ampere over the entire speed range. This controller is controlled speed and current using hybrid PI(HBPI) controller and estimation of speed using ANN. Also, this paper is proposed control of maximum torque per ampere(MTPA) of induction motor. This strategy is proposed which is simple in structure and has the honest goal of minimizing the stator current magnitude for given load torque. The performance of the proposed induction motor drive with maximum torque control using HBPI controller is verified by analysis results at dynamic operation conditions.

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