• Journal of Korean Society of Transportation
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• v.22 no.5
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• pp.139-149
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• 2004

As the expansion of road capacity has become impractical in many urban areas, congestion pricing has been widely considered as an effective method to reduce urban traffic congestion in recent years. The principal reason is that the congestion pricing may lead the user equilibrium (UE) flow pattern to system optimum (SO) pattern in road network. In the context of network equilibrium, the link tolls according to the marginal cost pricing principle can user an UE flow to a SO pattern. Thus, the pricing method offers an efficient tool for moving toward system optimal traffic conditions on the network. This paper proposes a continuous network design program (CNDP) in network equilibrium condition, in order to find optimal congestion toll for maximizing net economic benefit (NEB). The model could be formulated as a bi-level program with continuous variable(congestion toll) such that the upper level problem is for maximizing the NEB in elastic demand, while the lower level is for describing route choice of road users. The bi-level CNDP is intrinsically nonlinear, non-convex, and hence it might be difficult to solve. So, we suggest a heuristic solution algorithm, which adopt derivative information of link flow with respect to design parameter, or congestion toll. Two example networks are used for test of the model proposed in the paper.

• Journal of Radiation Protection and Research
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• v.26 no.2
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• pp.87-91
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• 2001

The optimized derived intervention levels for animal products were evaluated based on cost-benefit analysis. From these results, the radionuclide concentrations in animal feedstuffs for use were derived. It was shown that radionuclide concentrations in animal feedstuffs for use depend strongly on animal products, radionuclides and feeding period (period from the starting time to be led with contaminated feedstuffs to production time of animal products). In case of feedstuffs contaminated with long-lived radionuclides ($^{l37}Cs,\;^{90}Sr$), the feedstuffs with lower contamination should be supplied to animals with increase of feeding period due to the bioaccumulation of radionuclides. While, in case of feedstuffs contaminated with short-lived radionuclides ($^{131}I$), the feeding of higher contaminated feedstuffs was possible with increase of feeding period due to radionuclide decay. It was shown that $^{137}Cs$ concentration in animal feedstuffs lot use was lower than $^{90}Sr$ concentration. It is primarily, due to the higher feed-animal product transfer factor of $^{137}Cs$.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.1
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• pp.235-241
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• 2014

There are many traffic problems in a city such as parking, traffic jam caused by traffic induction facility. Therefore it is essential to demand for traffic demand management to building's owner whose building location causes traffic induction. According to the 90s traffic policy, government collects fee for traffic induction facility through traffic policy management and they encourage the building owner to join reduction of traffic jam program by reduction of traffic induction fee. However there are not many buildings owner joined this program because the program is not ghat beneficial. For example, if government set out parking guidance system (part of parking demanding system) in a city, it will reduce to 20% of traffic induced contributions but t can be used only once a year, so it is not efficient to used even it is valuable for about 10 years. In particular, according to the economic efficiency analysis, evaluate economically as net present value (NPV) to 2,160.44 million won, ratio of benefit/cost (B / C) to 2.44 during 10 years. Therefore this research will find out what is necessary for parking guidance system.

• Proceedings of the KOR-KST Conference
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• 1996.02a
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• pp.59-86
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• 1996

Current methods for evaluating unsignalized intersections, and estimating level-of-service (LOS) is determined from efficiency-based criteria such as little or no delay to very long delays. At present, similar procedures to evaluate intersections using safety-based criteria do not exist. The improvement of sight distances at intersections is the most effective way of improving intersection safety. However, a set of procedures is necessary to account for the limitations in current methodology. Such an approach would build upon such methods, but also account for: deficiencies in the current deterministic solution for the determination of intersection sight distances; opportunity for an accident and severity of an accident; and cost-effectiveness of attaining various levels of sight distances. In this research, a model that estimates the degree of safety at two-way stop-controlled intersections is described. Only crossing maneuvers are considered in this study because accidents caused by the crossing maneuvers are the dominate type among intersection accidents. Monte Carlo methods are used to estimate the hazard at an intersection as a function of roadway features and traffic conditions. Driver`s minimum gap acceptance in the crossing vehicles and headway distribution on the major road are used in the crossing vehicles and headway distribution on the major road are used in the model to simulate the real intersectional maneuvers. Other random variables addressed in the model are: traffic speeds; preception-reaction times of both drivers in the crossing vehicles and drivers in oncoming vehicles on the major road; and vehicles on the major roads. The developed model produces the total number of conflicts per year per vehicle and total potential kinetic energy per year per vehicle dissipated during conflicts as measurements of safety at intersections. Based on the results from the developed simulation model, desirable sight distances for various speeds were determined as 350 feet, 450 feet and 550 feet for 40 mph, 50 mph and 60 mph prevailing speed on the major road, respectively. These values are seven to eight percent less than those values recommended by AASHTO. A safety based level-of-service (LOS) is also developed using the results of the simulation model. When the total number of conflicts per vehicle is less than 0.05 at an intersection, the LOS of the intersection is `A' and when the total number of conflicts per vehicle is larger than 0.25 at an intersection, the LOS is `F'. Similarly, when the total hazard per vehicle is less than 350, 000 1b-ft2/sec2, the LOS is `F'. Once evaluation of the current safety at the intersection is complete, a sensitivity analysis can be done by changing one or more input parameters. This will estimate the benefit in terms of time and budget of hazard reduction based upon improving geometric and traffic characteristics at the intersection. This method will also enable traffic engineers in local governments to generate a priority list of intersection improvement projects.

• Progress in Medical Physics
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• v.14 no.3
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• pp.151-160
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• 2003

The application of more complex radiotherapy techniques using multileaf collimation (MLC), such as 3D conformal radiation therapy and intensity-modulated radiation therapy (IMRT), has increased the significance of verifying leaf position and motion. Due to thier reliability and empirical robustness, quality assurance (QA) of MLC. However easy use and the ability to provide digital data of electronic portal imaging devices (EPIDs) have attracted attention to portal films as an alternatives to films for routine qualify assurance, despite concerns about their clinical feasibility, efficacy, and the cost to benefit ratio. In this study, we developed method for daily QA of MLC using electronic portal images (EPIs). EPID availability for routine QA was verified by comparing of the portal films, which were simultaneously obtained when radiation was delivered and known prescription input to MLC controller. Specially designed two-test patterns of dynamic MLC were applied for image acquisition. Quantitative off-line analysis using an edge detection algorithm enhanced the verification procedure as well as on-line qualitative visual assessment. In conclusion, the availability of EPI was enough for daily QA of MLC leaf position with the accuracy of portal films.

• Journal of Preventive Medicine and Public Health
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• v.23 no.1 s.29
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• pp.11-21
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• 1990

This study refers to the problem of long-term inpatient flow in a general hospital. In this study, a queueing simulation model was developed for the two departments in the hospital with a homogeneous case mix and relatively many long-term inpatients in order to increase the turnover rate and hospital charges. Before the simulation n, the model was verified by the Kolmogorov-Smirnov test. The following results were generated by three alternative models of the special bed policies. 1. Alternative I : When long term inpatients were admitted to the wards belonging to departments A and B without transfer to other departments and special beds, the average turn-over rate decreased by 2-4% and the average hospital charges decreased by 70 million won. 2. Alternative II : When long-term inpatients were transferred to department C but the transfer of wards was determined by department C in order of clinical need, the average turnover rate increased by 4-13% but the average hospital charges decreased by 30 million won. This result was not greatly different from the present state. 3. Alternative III : When long-term inpatients were transferred to the special wards and department C simultaneously, the increase in the average turnover rate and hospital charges was equivalent to the increase of two beds in the special wards. When the special wards were allocated 16 beds, the average turnover rate of departments A and B increased by about 55% and 20% respectively. Also, the hospital charges increased by about 0.44 billion won. As a result, transfer to department C and the use of 16 beds in the special wards for long-term inpatients of departments A and B is expected to maximize the hospital revenue. However, as the above special bed policy can not increase the turnover rate above 60%, there is a need for a more comprehensive policy to further increase the rate. The development of an elaborate model should include the number of long-term inpatients in all clinical departments, the special wards system or an increase of hospital beds to handle admission needs, and the resources of the hospital by department. When the alternatives are evaluated, a cost-benefit analysis in addition to the turnover rate and the hospital charges should be considered.

• The Journal of the Korea Contents Association
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• v.17 no.4
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• pp.585-595
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• 2017

The purpose of this study is to analyze the difference of medical care between medical assistance and health insurance patients to evaluate the increase of medical care costs due to the moral hazard of medical care patients and to provide a basis for rational medical care policy decision. For this purpose, we compared health insurance benefit data for Seoul citizens by gender, age, and type of medical institutions. The results of the analysis are as follows. First, all of the hospitalized and outpatient use of the advanced general Hospitals, medical assistance patients were less than those of the health insurance patients, so that the medical assistance patients could not use the high cost medical services. Second, in general hospitals, patients with health insurance are often hospitalized. On the other hand, medical assistance patients use a lot of outpatient services because they are less burdened. Third, in hospitals and clinics, medical benefits patients often use inpatient and outpatient services. Therefore, medical assistance patients are likely to use unnecessary medical care of outpatient and hospitalization clinics and hospitals, outpatient of general hospitals. But, in hospitalization and outpatient use in advanced general hospitals and medical assistance patients can not use due to excessive medical burden. Therefore, the policy to reduce the burden of medical expenses for patients with severe illness will continue, and the medical care patients using clinics and hospitals should be careful not to use unnecessary medical services.

• Proceedings of the Korea Technology Innovation Society Conference
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• 1999.05a
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• pp.539-563
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• 1999

이 논문은 정보통신정책 목표와의 연관성 속에서 정보통신연구개발사업의 우선순위를 설정함과 아울러 비용효과성에 바탕을 둔 적정 자원배분 도출하는데 주안점을 두고 있다. 복합적인 목표를 가진 연구개발사업에 대해 사업부문별 그리고 기술분야별로 객관적이면서도 설득력있는 자원배분지침을 마련하기 위하여 본 연구는 다기준의사결정(MCDA: Multi-criteria Decision Analysis) 방법을 채택하고 있다. 이 방법론에서는 사업의 목표와 우선순위 판단기준 및 사업대안이 계층적으로 연계된 분석구조를 설계하여 사업대안의 우선순위를 먼저 설정하고, 여기에 정수계획법(Integer Programming)을 결합하여 사업의 목표와 연계된 비용-편익 관계(Cost-benefit relationship)를 최적화하는 바탕 위에서 사업대안별 자원배분 시나리오를 제시하게 된다. 이러한 절차로 사업부문별 및 기술분야별로 각각 도출된 8개의 자원배분 시나리오는 자원배분 경향치의 안정성(Stability) 분석과 자금지원의 과부족에 대한 현실적 적합성(Relevance) 분석을 거쳐 최종적으로 하나의 적정 자원배분방안으로 수렴되도록 하였다. 우선순위 설정에 기초가 되는 사업대안의 편익에 대한 자료는 전문가의 정성적 판단을 통해 수집되었는데, 이를 위해 정보통신기술 부문에서 활동 중인 중견 이상의 총 58명의 산학연 전문가를 대상으로 한 조사를 실시하였다. 먼저, 기초기반ㆍ전략기술개발사업, 연구ㆍ기술인력양성사업, 산업응용기술개발사업, 기술기반조성사업 등 4대 사업부문에 대해서는 (ⅰ) 정보통신 기술능력의 축적, (ⅱ) 정보통신산업의 경쟁력 강화, (ⅲ) 정보통신기반의 기술고도화, (ⅳ) 정보화를 위한 기술역량의 제고 등 주요 사업의 편익을 나타내는 4개 기준으로 우선 순위를 판단하였고, 정보통신망기술, 전파 및 RF 기술, 정보처리기술, 반도체 소자/설계 기술 등 13개 기술분야에 대해서는 (ⅰ) 공공정책적 임무에 대한 기여, (ⅱ) 기술자립기반의 확충, (ⅲ) 기술발전성과 기술적 파급효과, (ⅳ) 기술적 산물의 시장잠재력 등 기술분야 연구개발을 통한 편익을 나타내는 4개 기준으로 우선순위를 판단하였다. 우선순위는 사업대안에 대한 가중치로 표시되었고, 적정 자원배분방안은 추정된 총예산 규모에 따라 지원수준에 대한 일정한 제약조건 하에서 비용-편익 관계에 따른 자원의 최적 할당량으로 제시되었다. 본 연구는 총예산 규모의 가변성, 사업 및 기술분야 대안의 분류체계에 대한 공감대 부족, 사업목표의 상호연관성과 우선순위 판단기준의 부분적 중첩성 등 여러 제약요인이 있어 도출된 구체적인 수치보다는 방향성에 더 큰 의미를 부여하는 것이 바람직하다. 그러나, 이러한 연구의 한계에도 불구하고 도출된 우선순위와 적정 자원배분방안은 문제해결의 실행타당성을 감안하여 비교적 객관적이고 균형있는 결과로 판단된다.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.921-932
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• 2010

Metropolitan railway headway is calculated and decided by external conditions such as appropriate level of service and competitiveness rather than passenger demand for the peak time which is based on transport passenger capability of train. On contrast of inter-city urban railways, train time intervals of sub-urban metropolitan railway were fixed more than 20 mins in the peak time which results in low level of convenience. Big gap of headway brings a vicious circle of deteriorating competitiveness and decreasing the number of customers. Also this time gap of train interval results in stagnation of passenger demand, and makes it difficult to reduce headway. This thesis is a basic research to identify headway problems and their solutions of metropolitan railway. This thesis suggests passenger demand and the calculated standard for setting the headway, and reviews the level of passenger crowdedness, the numbers of coach for each train and time-competitiveness. At the last, thesis suggests the need for making headway by means of train services throughout benefit & cost analysis. And it also recommends the improved calculating method of setting up headway considering the different train headway standards by regional situation, flexibility in the number of coaches for a train, government policy to activate railway business and the need for setting up the standard for train service level.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.4
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• pp.67-77
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• 2000

For successful privatization of environmental facility, a sound environmental policy is required to satisfy social motivation and economic. The primary purpose of environmental facility is not profit, but to supply a good quality service, an efficient management tool is needed to run the facility. In foreign countries, the privatization policy was originally based on the principle of complete competition achieving economic effiency. There were efficient cooperation and division of labor between civillian and public sector. First of all, the local government had independant budget. But, we found that the environmental facility have two important problems, the first is low effiency of operation and the second is comsumed to government finances as a homemade rate 50% in the technic application For a successful privatization of the environmental facility, The law of private capital introduction should be amended to promote fund raising. There are some other strategies ; overcoming of Nimbyism, research development of the privatization, field trip to the successful foreign environmental facilities. To support an efficient privatization policy, the environmental budget should be managed by cost-benefit analysis.