• 한국도로학회논문집
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• 제16권3호
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• pp.75-84
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• 2014

PURPOSES : Traffic congestions which occur in the intersections of arterials lead to mobility and environment problem, and then traffic agencies and engineers have been struggling for mitigating congestions with greenhouse gas emissions. As an alternative of solving theses problems, this study is to introduce a low-cost and high-effectiveness countermeasure as unconventional intersections which are successfully in operation in U.S.. The main feature of unconventional intersections is to reroute turning movement on an approach to other approach, which consequently more green time is available for the progression of through traffic. Due to improved progression, this unique geometric design contributes to reduce delays with greenhouse gas emission and provides a viable alternative to interchanges. This study is to evaluate the potential operation and environment benefits of unconventional intersections. METHODS : This study used the VISSIM model with Synchro and EnViVer. Synchro is to optimize signal phases and EnViVer model to estimate the amount of greenhouse gas emissions by each condition. RESULTS : The result shows that unconventional intersections lead to increase the capacity and to reduce greenhouse gas emissions, compared to existing intersections. CONCLUSIONS : Unconventional intersections have the ability to positively impact operations and environments as a low-cost and high-effectiveness countermeasure.

• 대한교통학회지
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• 제26권4호
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• pp.51-61
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• 2008

2004년을 기준으로 전국 15개 지방공항 가운데 제주와 김포, 김해공항을 제외한 나머지 공항 들은 해마다 수십억 원의 적자를 내고 있는 실정이다. 지방공항들의 실패원인으로 수요예측 오류의 문제가 대두되어 왔다. 이에 소형 항공기를 이용해 정기서비스를 제공하는 저비용항공의 진입을 통해 소비자의 편의를 증진시키고 지방공항을 활성화해야 한다는 주장이 사회적인 공감을 얻고 있다. 따라서, 본 연구에서는 (1) 기존항공과 고속철도와 저비용항공 3자 사이의 고속교통통행수단 선택모형을 제시하고 (2) SP조사를 통하여 서울-대구간 저비용항공의 이용수요를 추정하고, (3) 추정모형을 설정하여 정책수단별 효과 분석을 실시하였다. 분석 결과, (1)서울-대구간 고속교통수단 선택에 있어서 저비용항공의 진입은 요금과 가격이 유의미한 영향을 미치는 것으로 나타났으며, (2)저비용항공의 요금이 KTX에 비해 훨씬 저렴한 38,000원 수준으로 정해질 경우에도 총통행시간이 KTX와 시간이 동일하게 소요되는 지역의 경우 저비용항공의 선택확률은 0.1 정도로 작게 나타나 통행수단 전환효과는 그리 크지 않을 것으로 분석되었다. (3)향후 서울-대구간 저비용항공 취항시의 요금은 38,000원${\sim}$44,000원 사이에서 결정되어야 할 것으로 보이며, 그 이상의 요금으로 결정될 경우 큰 수요를 기대하기 어려울 것으로 판단된다.

• 전력전자학회논문지
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• 제14권1호
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• pp.23-30
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• 2009

본 논문에서는 LCD TV의 인치에 따라 다르게 적용되는 기존의 PID(Power-Integrated Drive)시스템과 PSD(Power-Separated Drive)시스템을 검토하여, 두 시스템의 장점만을 모아 LCD TV 전원 시스템의 표준화가 가능한 새로운 방식의 구동 전원 통합 시스템을 제안한다. 제안 시스템은 가격 및 효율이 우수한 2단 구성으로 이루어져 있고, 안전규격을 만족하기 위하여 1:1 트랜스포머를 사용하였다. 인버터 부의 최적 동작을 위해 인버터 구동신호의 주파수와 시비율을 고정하고 펄스 개수를 제어하는 Pulse Count Modulation(PCM)방식을 채용 하였다. 제안 시스템의 인버터 단은 전 부하 범위에서 영전압 스위칭이 가능하여 스위치의 발열이 우수하고, 별도의 전류 평형 트랜스포머가 필요치 않으므로 Balance Coil의 삭제가 가능하다. 이로 인해 신뢰성이 높은 제품 구성이 가능하고, PCB Size 축소 및 제작 원가가 낮아지는 장점을 갖는다. 최종적으로 제안 시스템을 기존 시스템과 비교 및 실험적 검증을 통하여 제안 시스템의 우수성을 확인한다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권6호
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• pp.2317-2322
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• 2015

Background: Despite the increasing number of screening examinations performed for cervical cancer utilizing the Papanicolaou smear test (Pap test), few studies have examined whether this strategy is cost-effective in Korea. Objective: This study was conducted to evaluate the cost-effectiveness of cervical cancer screening strategies incorporating the Pap test based on age at the start and end of screening as well as screening interval. Materials and Methods: We designed four alternative screening strategies based on patient age when screening was started (20 or 30 years) and discontinued (lifetime, 79 years). Each strategy was assessed at screening intervals of 1, 2, 3, or 5 years. A Markov model was developed to determine the cost-effectiveness of the 16 possible cervical cancer screening strategies, and this was evaluated from a societal perspective. The main outcome measures were average lifetime cost, incremental quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratio (ICER). Results: Compared with various strategies comprising younger starting age, discontinuation age, and longer screening intervals, strategies employing annual screening for cervical cancer starting at a target age of 30 years and above were the most cost-effective, with an ICER of 21,012.98 dollars per QALY gained (with a Korean threshold of 30,000,000 KRW or US$27,272). Conclusions: We found that annual screening for cervical cancer beginning at a target age of 30 years and above is most cost-effective screening strategy. Considering the potential economic advantages, more intense screening policies for cervical cancer might be favorable among countries with high rates of cervical cancer and relatively low screening costs.

• 전기전자학회논문지
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• 제22권3호
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• pp.716-722
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• 2018

This paper presents a voltage angle control strategy for surface permanent magnet synchronous motor (SPMSM) drives used in low-cost applications, wherein a current vector control is not employed. In the proposed method, the current vector control scheme, which requires high precision phase-current sensing units and a fast calculation capability of a motor drive controller, is replaced with the voltage angle controller. The proposed voltage angle controller calculates a d-axis voltage command to make the d-axis current zero by using a simple equation obtained from the voltage equation of SPMSM. The proposed method shows performance similar to the current vector controlled SPMSM drive during steady-states and its structure is very simple and thus it can be easily implemented with a low-cost microcontroller. The effectiveness of the proposed method is verified through simulations and experiments.

• 수산해양교육연구
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• 제14권1호
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• pp.57-73
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• 2002

Illegal fishing is often cited as a principal cause of the failure of fisheries management, expecially fishing efforts regulations in traditional fisheries management. Usually, illegal fishing problems are perceived to be equivalent to inadequate enforcement, and policy prescription then follow to strengthen enforcement programs. The purpose of this paper is to analyze the illegal fishing behavior relatively recent emphasis on fishing efforts regulations in traditional fisheries management. The analysis focuses on measuring, explaining and developing the effectiveness way of enforcement strategies responding to imperfectly managed fishing efforts regulations through illegal fishing behavior and avoid enforcement fishing efforts measures. A model of fishermen fishing behavior and profit-maximizing decision making is analyzed to determine optimal fishing at individual fisherman level in response to fishing efforts regulation. The results of economic analysis of the enforcement of illegal fishing in traditional fisheries management results are as follows: First, illegal fishing will occur only if enforcement effort is not so high as to remove the incentive to do so, and if the effectiveness of avoidance is not too great, nor its cost too low. Second, avoidance effort will occur at a level jointly proportional to the extent of illegal activity and of enforcement; for given levels of the latter, the desired avoidance effort increase with its effectiveness and decrease with its cost Third, to improve the effectiveness of enforcement, understanding avoidance behavior appears to be crucial to any efforts. Forth, enforcement and fishermen behavior interact depends strongly on characteristics of avoidance, specifically its cost and effectiveness. When avoidance is neither too cheap nor too effective, the interaction is regular. Fifth, in this case, at low levels of enforcement, fishers respond to increases in enforcement by increasing avoidance, but at higher enforcement levels, it becomes uneconomical to continue to do so, and avoidance decreases with enforcement. Sixth, illegal fishing activity decreases steadily with enforcement, so the fishery manager is able, in theory, to reduce illegal fishing toward zero by increasing enforcement. If, however, avoidance is very inexpensive and/or very efficient/ then the optimal level of avoidance will increase indefinitely with increasing enforcement. Finally, less fishery enforcement is required if fishermen have less incentive to overfish, and fishermen have less incentive to avoid fishery enforcement measures.

• Asian Pacific Journal of Cancer Prevention
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• 제15권19호
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• pp.8503-8508
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• 2014

Background: After the WHO recommended HPV vaccination of the general population in 2009, government support of HPV vaccination programs was increased in many countries. However, this policy was not implemented in Korea due to perceived low cost-effectiveness. Thus, the aim of this study was to analyze the cost-utility of HPV vaccination programs targeted to high risk populations as compared to vaccination programs for the general population. Materials and Methods: Each study population was set to 100,000 people in a simulation study to determine the incremental cost-utility ratio (ICUR), then standard prevalence rates, cost, vaccination rates, vaccine efficacy, and the Quality-Adjusted Life-Years (QALYs) were applied to the analysis. In addition, sensitivity analysis was performed by assuming discounted vaccination cost. Results: In the socially vulnerable population, QALYs gained through HPV vaccination were higher than that of the general population (General population: 1,019, Socially vulnerable population: 5,582). The results of ICUR showed that the cost of HPV vaccination was higher for the general population than the socially vulnerable population. (General population: 52,279,255 KRW, Socially vulnerable population: 9,547,347 KRW). Compared with 24 million KRW/QALYs as the social threshold, vaccination of the general population was not cost-effective. In contrast, vaccination of the socially vulnerable population was strongly cost-effective. Conclusions: The results suggest the importance and necessity of government support of HPV vaccination programs targeted to socially vulnerable populations because a targeted approach is much more cost-effective. The implementation of government support for such vaccination programs is a critical strategy for decreasing the burden of HPV infection in Korea.

• 한국산학기술학회논문지
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• 제22권4호
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• pp.345-352
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• 2021

육군은 교육훈련 효과를 향상시키기 위해 노력을 경주하고 있다. 그러나 실제 훈련 시 많은 제한사항으로 인해 실전적인 교육훈련이 제한된다. 이러한 제한사항을 극복하기 위해 가상현실 기술을 활용하고 있다. 가상현실 기술은 다양한 유형으로 발전하고 있으며, 육군은 비용 대 교육효과를 고려하여 가상현실 훈련체계를 도입할 필요가 있다. 육군은 실제 장비와 유사하게 제작된 고비용의 시뮬레이터형을 주로 사용하고 있다. 최근에는 HMD(Head Mounted Display, 이하 HMD)를 착용한 저비용의 몰입형 가상현실 훈련체계도 사용 중이다. 본 연구는 육군 방공학교에서 운영중인 시뮬레이터형과 몰입형 가상현실 훈련체계에 대한 비용 대 교육효과를 분석한다. 연구 방법은 첫 번째, 계층적 분석기법(AHP : Analytic Hierarchy Process, 이하 AHP)으로 교육효과를 분석한다. 두 번째, 비용은 가상현실 훈련체계의 제작 비용을 적용하여 비용 대 교육효과를 분석한다. 분석결과, 비용 대 교육효과는 몰입형이 시뮬레이터형보다 3.4배 높은 것으로 확인되었다. 이번 연구결과를 통해 가상현실 훈련체계의 비용 대 교육효과 분석을 위한 기초자료로 활용이 가능 할 것이다.

• 전자공학회논문지B
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• 제32B권10호
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• pp.1314-1325
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• 1995

In this paper, we describe hardware implementation of VSB (Vestigial SideBand) mo-dulation equalization systems for HDTV (High Definition TeleVision). By modifying an adaptive equalization algorithm, we propose a hardware architecture with a low hardware cost and the performance close to floating-point operations. We also employ the pipeline concept to reduce the hardware cost. The effectiveness of the proposed hardware architecture is de- monstrated through computer simulation and the optimization result of VHDL circuit descriptions.

• 전기학회논문지
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• 제63권10호
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• pp.1371-1376
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• 2014

In this paper, 4-phase switched reluctance motor(SRM) with 8-stator and 6-rotor pole structure is proposed for a high speed fan with a low voltage. The air blower has unidirectional rotation characteristics and requires a low torque ripple and noise as well as high efficiency. To achieve the requirements, voltage and current according to loading condition of limited specification is considered. Design process is to select the bore diameter, pole arc, york of stator and rotor to get a high torque and efficiency. To verify the validity of the proposed structure, finite element method(FEM) is employed to get the performances. And the converter for the proposed SRM is employed a 1.5q power converter for cost effectiveness. Prototype SRM is manufactured and tested, and the test results show this design is within the specification and good for the air blower applications.