• 대한조선학회논문집
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• 제59권1호
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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.

• 한국산림과학회지
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• 제106권4호
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• pp.473-479
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• 2017

본 연구는 유실수, 특용수, 산채 및 고로쇠 등을 주업으로 임업만 생산했을 경우와 자연순환농법으로 닭을 방사하여 키우는 산지양계와 결합한 복합경영일 경우의 조수입이 어느 정도 향상되었는지를 분석하였다. 연구대상지는 충청북도 충주시, 경상북도 경산시, 강원도 화천군에 위치하고 있는 3곳의 산지양계 복합경영 현장실연 임가이다. 그리고 현장 면담조사를 통해 2015년도 기준의 경영비와 조수입을 조사하여 산지양계의 비용구조와 경영성과를 비교 분석하였다. 연구결과, 충주는 조수입이 25,608,000원, 경영비가 20,217,571원으로 소득은 5,390,429원으로 분석되었고, 경산은 조수입이 33,950,000원, 경영비가 18,655,714원으로 소득은 15,494,286원인 것으로 나타났다. 화천은 조수입이 31,850,000원, 경영비가 13,143,000원으로 소득은 18,707,000원이었다. 그리고 판매량과 비용이 일치하는 손익분기 판매량은 충주는 617마리, 경산은 125마리, 화천은 63마리로 나타났다. 1마리당 가격에서 차지하는 원가율은 충주는 79%를 차지하였고, 경산은 55%, 화천은 41%를 차지하였고 이에 따른 마진율은 충주는 21%, 경산은 45%, 화천은 59%로 나타났다. 또한 산지양계복합경영의 소득효과는 조수입 기준으로 평가한 결과, 임업만 주업으로 할 때 보다 충주가 16%, 경산이 18% 그리고 화천이 11%로 증가한 것으로 나타났다.

• 한국병원경영학회지
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• 제2권1호
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• pp.1-21
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• 1997

In order to analyze the shifts in the volume and profits of Computed Tomography(CT) and Magnetic Resonance Imaging(MRI) utilization for a year before and after the implementation of insurance coverage for CT, this study has been undertaken examining CT and MRI cost data from 'Y' University Hospital situated in Seoul, Korea. Following are the results of this study: 1. The medical insurance payment for CT, implemented on January 1, 1996, increased CT utilization from January 1996 to April 1996 due to low insurance premiums: however, from May 1996 the number of CT cases significantly decreased as a result of strengthened medical cost reviews and the new 'Detailed standards for approval of CT' announced near the end of April 1996 by the insurer. 2. Since the implementation of insurance coverage for CT, CT fee reduction rates for reimbursements by the insurer to the hospital were 50% and 40% for January and February, respectively, and 31% and 15% for March and April. A significant point in the lowering of the reduction rate was reached in May at 11%; furthermore, since June the reduction rate fell below the average reduction rate for reimbursements for all procedures. If the 'Detailed standards for approval of CT' had been announced before the implementation of insurance coverage for CT, CT utilization would not have been so high due to the need to meet those 'standards'. In addition, loss of hospital profits resulting from the reduction for reimbursements would not have occurred. 3. The shifts in MRI utilization showed that there was no particular change with the beginning of insurance coverage for CT, and the introduction of the 'Detailed standards for approval of CT' made MRI utilization increase because MRI is free of restrictions imposed by the insurer. 4. The relationship between CT utilization and MRI utilization showed that they were supplementary to each other before insurance coverage for CT, but that CT was substituted for MRI because of strengthened medical cost reviews after t~e beginning of insurance coverage for CT. 5. The shifts in volume by patient characteristics showed that the number of inappropriate case patients, according to the insurer's "Standards for approval", decreased more than the number of appropriate case patients after the introduction of insurance coverage for CT. Therefore, the health insurance fee schemes for CT have influenced patient care. 6. The shifts in profits from CT utilization showed a net profit decrease of 31.6%. In order to match the pre-coverage profit level, 5,471 more cases would need to be seen and productivity would need to be increased by 32.7%. This profit decrease resulted from a decrease of CT utilization and low reimbursements. With insurance coverage, net profits from CT were 24.4%, and a margin of safety ratio was 39.6%. Because of the net profits and margin of safety ratio, CT utilization fees for insured appropriate cases could not be considered inappropriate. 7. The shifts in profits from MRI utilization before and after the introduction of CT coverage showed that in order to match pre-CT coverage profit levels, 2,011 more cases would need to be seen and productivity would need to be increased by 9.2%. The reasons for needing to increase the number of cases and productivity result from cost burdens created by adding new MRI units. But with CT coverage already begun, MRI utilization increased. Combined with a minor increase in the MRI fee schedule, MRI utilization showed a net profit increase of 18.5%. Net profits of 62.8% and a 'margin of safety ratio' of 43.1% for MRI utilization showed that the hospital relied on this non-covered procedure for profits. 8. The shifts in profits from CT and MRI utilization showed the net profits from CT decreased by 2.33billion Won while the net profits from MRI increased by 815.7million Won. Overall, these two together showed a net profit decrease of 1.51billion Won. The shifts in utilization showed a functional substitutionary relationship, but the shifts in profits did not show a substitutionary relationship. From these results, We can conclude that if insurance is to be expanded to include previously uncovered procedures using expensive medical equipment, detailed standards should be prepared in advance. The decrease in profits from the shifts in coverage and changes in fees is a difficult burden that should be shared, not carried by the hospital alone. Also, a new or improved fee schedule system should include revised standards between items listed and the appropriateness of the fee schedule should constantly be ensured. This study focused on one university hospital in Seoul and is therefore limited in general applicability. But it is valuable for considering current issues and problems, such as the influence of CT coverage on hospital management. Future studies will hopefully expand the scope of the issues considered here.

• 한국IT서비스학회지
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• 제18권5호
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• pp.209-224
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• 2019

When evaluating the performance of a NPD(New Product Development) project, it is common to evaluate the project performance according to the achievement of the planned goal in terms of time, quality and cost management, which are usually three main constraints of the project. The evaluation of the financial factors by which sales contributed to the return of the company is more influential. This is why companies need to increase sales and raise profits. Therefore, it is more reasonable to evaluate the sales performance of NPD projects over a certain period of time against the input costs. At this time, we can analyze the causes of inefficient projects and compare them with other projects and find out how to improve the sales performance to help the company increase its competitiveness. In this paper, we analyze the relative efficiency of the sales performance on the input of the projects by using the actual sales in the period of one year after mass production of the NPD projects of 'S' company in ICT industry. Input factors include developer resource and development cost for the NPD reported after the project has been completed, the delay weeks for the schedule targeted at the project planning stage, and the number of quality issues due to development design faults during initial mass-production. The sales figure and the contribution margin of the product after one year from the start of mass production are defined as the output factors. In this paper, we analyze the efficiency of the projects by using data envelope analysis (DEA). As a result, we found out the reason of the inefficient project of DMUs according to the differences in the characteristics of the efficient and inefficient B2B markets based on the result of DEA of NPD projects. Thus, the goal of this paper is to identify strategies for improving sales performance of NPD projects in inefficient markets.

• 한국병원경영학회지
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• 제14권2호
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• pp.1-20
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• 2009

The purpose of this study is to find the determinant variables to make profitability in regional public hospitals. The data come from financial statements and annual reports of 34 regional public hospitals for five years (from year 2003 to year 2007). The T or F-test and hierarchical multiple regression analysis are used. The dependant variables are the profitability indicators, ordinary income to total asset and operating margin to gross revenue, and the independent variables are general characteristics, diagnosis and treatment patterns, financial and public benefits. The findings of this study are summarized as follows. First, Variables affecting the profitability indexes revealed from DEA results is the bed occupancy rate, number of hospitalized patients to outpatients, ratio of first medical examination for outpatients, number of daily patients per medical specialist, labor cost per patient and managerial expenses per patient. Second, the ordinary income to total asset representing the asset usage performance is affected by the average hospitalized days, bed occupancy rate, labor cost per patient and ratio of patients with medical insurance coverage. Third, the operating martin to gross revenue obtained from the actual operations of hospitals has its significance with the bed occupancy rate, number of hospitalized patients to outpatients, managerial expenses per patient and public benefit indicator. This study has some restriction not to use pannel data analysis, although it used data for five years. Accordingly, various additional studies should be done to supplement such problems.

• 한국병원경영학회지
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• 제27권3호
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• pp.26-38
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• 2022

Purposes: We analyzed the profitability determinants of regional public hospitals during the entire period between 2010 and 2020 and the period before and after COVID-19. We intended to provide fundamental data for developing publicness evaluation index and task of establishing and expanding regional public hospitals. Methodology: The financial and non-financial information of the regional public hospitals were used as the main analysis data; The financial data was established by the Center for Public Healthcare Policy of National Medical Center, and the non-financial data by the Health Insurance Review and Assessment Service. T-test and regression analysis were used. Findings: The results can be summarized in two. First, the main determinants of profitability of the regional public hospitals were appeared to be the total asset turnover rate and the labor cost rate. Second, during the COVID-19 pandemic in the regional public hospitals, the number of sickbeds, the number of isolation rooms, the total asset turnover rate and the labor cost rate appeared to be the factor worsening the profitability. Practical Implication: The results of this study suggests that the management of the regional public hospitals is not aiming for the profit making, but it performs the functions as the community healthcare safety net such as controlling infectious diseases.

• 에너지공학
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• 제24권2호
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• pp.129-143
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• 2015

기후변화와 에너지안보에 대한 우려가 심화되면서 온실가스 감축을 위한 다양한 방안들이 제시되어 왔다. 특히 수송부문에서의 온실가스 감축은 핵심적인 정책목표로 논의되었으며. 최근 자동차 배기가스 배출 규제가 강화되는 추세에서 온실가스 배출이 없는 전기차(EV) 도입이 다각도로 조명을 받고 있다. V2G(Vehicle-to-Grid)기술은 전기차시장의 급격한 성장 전망으로 인한 전력수요증가에 대응하는 기술로써, 전기차 소유의 경제성을 높여줄 뿐만 아니라 전력망 안정성을 유지하며 전력부하의 분산효과도 기대되고 있다. 본 연구는 V2G를 적용한 전기차의 총소유비용을 산출하여 이를 내연기관차와 일반전기차와 비교하였다. V2G를 도입한 전기차는 연 평균 약 21만원의 수익을 발생하여 V2G 서비스 공급 기간동안 총 211만원의 수익을 얻게 되는 것으로 나타났고, 이는 운영기간동안 총 242만원의 비용이 발생하는 일반전기차와 비교해 약 453만원의 차이가 난다. 따라서 V2G 전기차의 총소유비용은 동급 내연기관차보다 10.2% 높고 일반전기차보다 6.1% 낮은 결과가 도출되었다. 보조금이 없을 경우 전기차는 아직까지 내연기관차에 비해 소유비용이 높지만 V2G 도입은 전기차의 상대적 경제성을 높여주는 것을 확인하였다. 따라서 V2G 도입에 있어서는 전력망과 관련 산업이 얻는 긍정적 효과를 함께 고려하여 정책적 검토가 이뤄져야 한다.

• 한국경영과학회지
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• 제17권1호
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• pp.117-117
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• 1992

Pubilc utility industries including the electric utility industry are facing a new stream of privatization com-petition with the private sector and deregulation. The necewssity to solve now and in the future power supply and demand problems has been increasing through the sophisticated generation expansion plan(GEP) approach con-sidering not only KEPCo's supply-side resources but also outside resources such as non-utility generation(NUG) demand-side management (DSM). Under the environmental situation in the current electric utility industry a new approach is needed to acquire multiple resources competitively. This study presents the development of a modified electric generation expansion analysis system(EGEAS) model with avoided cost based on the existing EGEAS model which is a dynamic program to develope an optimal generation expansion plan for the electric utility. We are trying to find optimal GEP in Korea's case using our modified model and observe the difference for the level of reliabilities such as the reserve margin(RM) loss of load probability(LOLP) and expected unserved energy percent(EUEP) between the existing EGEAS model and our model. In addition we are trying to calculate avoided cost for NUG resources which is a criterion to evaluate herem and test possibility of connection calculation of avoided cost with GEP implementation using our modified model. The results of our case study are as follows. First we were able to find that the generation expansion plan and reliability measures were largely influenced by capacity size and loading status of NUG resources, Second we were able to find that avoided cost which are criteria to evaluate NUG resources could be calculated by using our modified EGEAS model with avoided cost. We also note that avoided costs were calculated by our model in connection with generation expansion plans.

• 한국재난정보학회 논문집
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• 제20권3호
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• pp.644-653
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• 2024

연구목적: 건설사고의 근본원인을 찾다보면 발주자의 무리한 공사비와 공기 책정의 문제로 귀결된다. 여기에 역량이 부족한 시공자의 저가입찰이 맞물리면서 공사의 착공 이전에 사고를 일으킬 수 있는 부적절한 공사 구조가 생성된다. 연구방법: 건설업 환경의 원청사 자원 부족이 협력사에게 전가되는 문제와 협력사, 그 소속 근로자는 최소 마진을 확보하기 위해 무리한 작업을 강행할 수밖에 없는 상황에 내몰리는 현상 분석. 연구결과: 건설 사고 근본을 거슬러 올라가면 물리적 현상부터 근본원인까지 여러 차원의 원인이 있는데도 지금까지의 사고예방 대책은 거의가 현상 대응형 1차원 수준에 머물러 있는 이유는 근본원인 분석 부족이다. 결론: 발주자(처)와 정부 주도의 안전사고 대책으로 패러다임 전환이 필요하고, 5Why와 같은 근본원인 분석 기법을 통하여 건설사고의 Root Cause를 찾아야 건설재해는 감소 된다.

• 전기학회논문지
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• 제56권10호
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• pp.1731-1737
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• 2007

The Korea electricity wholesale market is operated under the cost-based-pool system and the government regulation to the new generation capacities in order to insure the resource adequacy. The goal of government's regulation is the electricity market stability by attracting proper generation investment while keeping the reliability of system. Generation companies must mandatory observe that government plan by now. But if the restructuring is to be complete, generation companies should not bear any obligation to invest unless their profitability is guaranteed. Namely the investors' behavior will be affected by the market prices. In this paper, the system dynamics model for Korea wholesale electricity market to examine whether competitive market can help to stabilize is developed and analyzes the investors behavior. The simulation results show that market controlled by government will be operated stable without resulting in price spike but there is no lower price because of maintaining the reasonable reserve margin. However, if the competition is introduced and the new investment is determined by the investor's decision without government intervention, the benefits from lower wholesale price are expected. Nevertheless, the volatility in the wholesale market increases, which increases the investment risks.