• Journal of the Korean Society for Library and Information Science
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• v.4
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• pp.43-71
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• 1975

Operations research has developed rapidly since its origins in World War II. Practitioners of O. R. have contributed to almost every aspect of government and business. More recently, a number of operations researchers have turned their attention to library and information systems, and the author believes that significant research has resulted. It is the purpose of this essay to introduce the library audience to some of these accomplishments, to present some of the author's hypotheses on the subject of library management to which he belives O. R. has great potential, and to suggest some future research directions. Some problem areas in librianship where O. R. may play a part have been discussed and are summarized below. (1) Library location. It is usually necessary to make balance between accessibility and cost In location problems. Many mathematical methods are available for identifying the optimal locations once the balance between these two criteria has been decided. The major difficulties lie in relating cost to size and in taking future change into account when discriminating possible solutions. (2) Planning new facilities. Standard approaches to using mathematical models for simple investment decisions are well established. If the problem is one of choosing the most economical way of achieving a certain objective, one may compare th althenatives by using one of the discounted cash flow techniques. In other situations it may be necessary to use of cost-benefit approach. (3) Allocating library resources. In order to allocate the resources to best advantage the librarian needs to know how the effectiveness of the services he offers depends on the way he puts his resources. The O. R. approach to the problems is to construct a model representing effectiveness as a mathematical function of levels of different inputs(e.g., numbers of people in different jobs, acquisitions of different types, physical resources). (4) Long term planning. Resource allocation problems are generally concerned with up to one and a half years ahead. The longer term certainly offers both greater freedom of action and greater uncertainty. Thus it is difficult to generalize about long term planning problems. In other fields, however, O. R. has made a significant contribution to long range planning and it is likely to have one to make in librarianship as well. (5) Public relations. It is generally accepted that actual and potential users are too ignorant both of the range of library services provided and of how to make use of them. How should services be brought to the attention of potential users? The answer seems to lie in obtaining empirical evidence by controlled experiments in which a group of libraries participated. (6) Acquisition policy. In comparing alternative policies for acquisition of materials one needs to know the implications of each service which depends on the stock. Second is the relative importance to be ascribed to each service for each class of user. By reducing the level of the first, formal models will allow the librarian to concentrate his attention upon the value judgements which will be necessary for the second. (7) Loan policy. The approach to choosing between loan policies is much the same as the previous approach. (8) Manpower planning. For large library systems one should consider constructing models which will permit the skills necessary in the future with predictions of the skills that will be available, so as to allow informed decisions. (9) Management information system for libraries. A great deal of data can be available in libraries as a by-product of all recording activities. It is particularly tempting when procedures are computerized to make summary statistics available as a management information system. The values of information to particular decisions that may have to be taken future is best assessed in terms of a model of the relevant problem. (10) Management gaming. One of the most common uses of a management game is as a means of developing staff's to take decisions. The value of such exercises depends upon the validity of the computerized model. If the model were sufficiently simple to take the form of a mathematical equation, decision-makers would probably able to learn adequately from a graph. More complex situations require simulation models. (11) Diagnostics tools. Libraries are sufficiently complex systems that it would be useful to have available simple means of telling whether performance could be regarded as satisfactory which, if it could not, would also provide pointers to what was wrong. (12) Data banks. It would appear to be worth considering establishing a bank for certain types of data. It certain items on questionnaires were to take a standard form, a greater pool of data would de available for various analysis. (13) Effectiveness measures. The meaning of a library performance measure is not readily interpreted. Each measure must itself be assessed in relation to the corresponding measures for earlier periods of time and a standard measure that may be a corresponding measure in another library, the 'norm', the 'best practice', or user expectations.

• Journal of the Korean association of regional geographers
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• v.21 no.3
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• pp.474-488
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• 2015

Conflicts in the construction of large public facilities carried out as national projects are crucial issues we have to deal with. There are growing concerns for and oppositions to large construction projects in terms of environmental deterioration and the dissolution of local communities. In the case of projects that promise the creation of jobs and investment, the competition and disputes are increasing and being intensified. Therefore, there is a considerable amount of study on the competitions and conflicts between regions. Previous studies have focused on the procedures of public policy, governance structure, the role of local media. Contrary to the previous studies, this study investigates the spatial ways of constructing conflicts. Based on the analysis of the project of "Southeastern New International Airport", there is a mismatch between the spatial boundary of cost/benefit and agents (regions) of disputes. The agents of conflicts also show the politics of multiple scales by constructing alliances and breaking the network in the process of the airport project. The findings suggest that the conflicts on regional development should be understood as the construction of dynamic regional politics on regional development rather than as the by-product in the practice of policies.

• The Korean Journal of Applied Statistics
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• v.28 no.4
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• pp.643-661
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• 2015

Korea Teachers Pension (private school pension) is a mandatory pension and a social security system for private school teachers to ensure the stability of subscribers by a supplying pension when they (and their dependents) face future economic risk due to retirement or death. Therefore, the Teachers Pension must provide stability and sustainability in regards to adequacy of income and to function as a pension. However, the Government Employees Pension System (GEPS) of Korea (the most representative special occupation pension) recorded a fiscal deficit in 2001 and with an accumulated deficit that is expected to grow; subsequently, various plans for the reform of GEPS have been actively discussed. The Korea Teachers Pension system is based on the GEPS scheme and is not free from the GEPS discussions on reforms of national pension. The current system for the Teachers Pension needs to be improved because it is expected to be depleted within the next 30 years due to low fertility and an aging population in Korea. This study discusses existing Teachers Pension schemes problems and suggests a projection method and revised plans to improve it. We use long-term financial projections of the Teachers Pension to estimate the fund exhaustion point and the minus balance of the financial scale as well as analyze the supply-demand burden structure that reflects the future population structure to propose Teachers Pension reforms that will improve stability and adequacy.

• 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.