• Health Policy and Management
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• v.10 no.3
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• pp.108-128
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• 2000

The Korean government has implemented the policy for merging 141 health insurers into Korean Unified Health Insurer (KUHI) in July of 2000. The unification of multiple insurers will definitely effect the stability of financial management, equity of premium burdens and efficiency of administrative management. However, it is difficult to predict what forms the far-reaching effects of the unification would take. Thus, pursuing the unification may be express as a huge policy experiment. In order to lead the unification, which lies on a crossroad between success and failure, to the road of success, we need to infer the problems and obstacles predicted in the step-wise processes of merging organizations, finances and the systems of computing premium, and come up with the effective means to maintain the stability of financial management, to improve the equity of premium burdens and to increase the efficiency of administrative management. Thus, I first described the changes of the Korean medical insurance system, and analyzed the performances of self-employed medical insurance 1 year after the integration of societies in October of 1998. At the base of examining the stability of financial management, equity of premium burdens and efficiency of administrative management, I predicted the problems and obstacles that could occur after the unification of the multiple medical insurers, and proposed a few ways of leading the unification of the multiple medical insurers in Korea to success. The most worried factor is that insurance finance would become unstable since the expansion of premium revenues is not easy because raising the premium for all Koreans is to be difficult. In addition, the unification of insurance finance could weaken the insurer's efforts for declaring real incomes of the self-employed and increasing the collection rate of premiums from them. This weakening would be the decisive factor of lowering the equity of premium contributions between the self-employed and employees. And bureaucratization and rigidity that are unavoidable in a gigantic unified organization could lower the efficiency of administrative management. Furthermore, by having 3 labor unions in the unified organization, it is possible to experience frequent difficulties and discords among the unions and between the unions and organization. Thus, when smooth pursuing of the unification of multiple insurers gets difficult, the social expenses derived from the failure would eventually end up on all Koreans. The unification is to be performed after coming up with the ways to eradicate these worries, so that the unification of multiple insurers would step onto the road of success.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.26-33
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• 2016

Recently, the use of transformer-less UPS has increased to improve the efficiency of UPS. However, transformer-less UPS is required in three-phase four-wire input IGBT PWM rectifier and the existing three-phase three-wire PFC algorithm cannot be applied in the three-phase four-wire system due to the neutral current problem of UPS input. To control the three-phase four-wire input IGBT PWM rectifier, there are two existing algorithms: 3D SVM and single phase control method. These two algorithms have advantages/disadvantages in controlling the rectifier. The single phase control method is unstable for controlling the rectifier and the 3D SVM method has a problem that must increase the L value of the input-side inductor considerably. Therefore, this paper proposes digital single phase control technology and another new algorithm considering the d-q control, to improve the characteristics of the existing control algorithm. In addition, this paper performed a simulation and experiment based on the proposed control algorithm. The simulation results showed that the proposed technology can control three-phase four-wire IGBT PWM rectifier in a stable manner and can also reduce the neutral current. The proposed algorithm is a useful tool for controlling the three-phase four-wire IGBT PWM rectifier.

• Journal of the Institute of Convergence Signal Processing
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• v.13 no.4
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• pp.220-232
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• 2012

In this paper, we investigate the correlation result due to the problems of delay tracking and fringe rotation module in the VCS(VLBI Correlation Subsystem). The VCS, FX-type correlator, adopts the delay tracking and fringe rotation module in order to compensate the delay change and fringe phase of wave signal from the radio source by Doppler's effect. The phase of observed data is also compensated by means of delay tracking and fringe rotation in the correlator, but we confirmed that the phase is unstable by applying long integration period of AIPS(Astronomical Image Processing System) rather than correlator. And the delay value of observed data has the errors of several tens nanoseconds than normal case at the analysis of correlation result. In addition, we found that the phase of correlation results is not connected as the unit of FFT-segment because the initial fringe phase at the fringe rotation module is not correctly determined. In this paper, in order to solve these problems, the original direction of 90 degree phase jump is reversely modified when the bit-shift occurred at the delay tracking. And the initial fringe phase at the fringe rotation module is correctly modified by using the initial phase of observed data. In addition, the parameter calculation module was abnormally operated as designed in the fringe rotation. So, the logical program by the VCS is modified so as to calculate the parameters correctly. Through the experiments of correlation processing over the above problems, the modified proposal algorithm is adequately corrected to the data analysis results, so that the experimental results make it clear for us to operate the developed VCS hardware correlator normally.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.6
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• pp.69-77
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• 2002

To acquire the dynamic response and design the controller of the airship, the longitudinal motion of the airship with respect to the vertical gust, which is the nonlinear system, was studied. The effects of the apparent mass and moment of the airship delay the dynamic response and the settling time, which are slower than those of conventional airplanes. The current object of the airship is designed to cruise at 500~1000m altitude. At that height, the atmospheric conditions are generally unstable by wind gust. In this paper, it has been studied for the case of vertical gust, since the apparent mass effects are dominant in has been studied for the case of vertical gust, since the apparent mass effects are dominant in that plane. In addition to the study of the dynamic responses of the airship, the controller was designed using the PID-controller. When the gust was applied, airship responses were recovered of equilibrium states. However, it takes too ling time for recovery and the speed of airship is reduced. So, the aim in this paper was to fasten the recovery speed and to get back the cruising velocity. The control parameters were determined from the stability mode analysis, and the control inputs were the thrust and the elevator deflection angle.

• Clinics in Shoulder and Elbow
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• v.17 no.1
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• pp.25-30
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• 2014

Background: Normal elbow joint kinematics has been widely studied in cadaver, whilst in vivo study, especially of the forearm, is rare. Our study analyses, in vivo, the kinematics of normal forearm and of malunited forearm using a three-dimensional computerized simulation system. Methods: We examined 8 patients with malunited Monteggia fracture and 4 controls with normal elbow joint. The ulna and radius were reconstructed from CT data placing the forearm in three different positions; full pronation, neutral, and full supination using computer bone models. We analyzed the axis of rotation 3-dimentionally based on the axes during forearm rotation from full pronation to full supination. Results: Axis of rotation of normal forearm was pitch line, with a mean range of 2 mm, from full pronation to full supination, connecting the radial head center proximally and ulnar fovea distally. In normal forearm, the mean range was 1.32 mm at the proximal radioulnar joint and 1.51 mm at the distal radioulnar joint. However in Monteggia fracture patients, this range changed to 7.65 mm at proximal and 4.99 mm at distal radoulnar joint. Conclusions: During forearm rotation, the axis of rotation was constant in normal elbow joint but unstable in malunited Monteggia fracture patients as seen with radial head instability. Therefore, consideration should be given not only to correcting deformity but also to restoring AOR by 3D kinematics analysis before surgical treatment of such fractures.

• Journal of the Korean association of regional geographers
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• v.7 no.1
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• pp.21-34
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• 2001

Summarized results of this study that examined the characteristics of farm household in suburban areas classified by the fanning types are as follows. When it was looked into with the side of farm household and his family, the type of the farm household in suburban areas are related to the quality of fanning labor rather than the quantity of it. Regardless of the type of the farm household, it depends upon the family labor (usually men and wives). And the age of farm manager is an important part in the quality of fanning labor. The size of the farm household is related to the individual fanning labor. The size of self-sufficient crops(mainly rice) farm household will be small as the farmer gets to be old. But the size of commercial crops farm household has less tendency to change in terms with the age of farm manager. The fanning commercialism takes an important part in the maintenance and development of suburban agricultural areas. But, in fact, there is a shortage of farming labor. So the physical condition of farmland is the most important part in agricultural durability. After this study, we can conclude that we won't have enough chance to solve the problem of family member separation and shortage of fanning labor even though it is in the suburban area or in the profitable farm until we give them more enough chance to get a job(except fanning) and the better education infrastructure. To make matters worse, the aggravation of farm house-hold's economy due to unstable price of farming products' threatens the agricultural durability. Consequently, in order to get a development of agriculture and rural community, a qualitative change with improvement of agricultural conditions and of products distribution system is needed.

• Journal of the Korean Data and Information Science Society
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• v.27 no.1
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• pp.45-65
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• 2016

Global competition and unstable economic situation in recent years have brought in adverse working conditions such as proliferation of temporary or part-time workers and new shift system. In this study we use exploratory data analysis method to find the relationship between some of the important variables which are related to working hours in KWCS (Korean Working Conditions Survey) and EWCS (European Working Conditions Survey). Next, working hours are explored in terms of sex, employment type, occupation and industry using 2006, 2010, 2011, 2014 KWCS data as well as 2010 EWCS data. Lastly, respondents are divided into two groups of healthy and nonhealthy workers and their working hours are explored in terms of the same categories as above. Finally, simple regression analysis is used to find the effect of health on weekly working hours and adjustment of the effect of health on weekly working hours is made using multiple regression analysis with some other independent variable such as sex, age and employment type included in the model.

• Journal of Korean Association for Spatial Structures
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• v.8 no.5
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• pp.47-58
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• 2008

Spatial structure is an appropriate shape that resists external force only with in-plane force by reducing the influence of bending moment, and it maximizes the effectiveness of structural system. With this character of the spatial structure, generally long span is used. As a result, large deflection is accompanied from the general frame. the structure is apt to result in a large deflection even though this structure experiences a small displacement in absence. Usually, nonlinear analysis in numerical analysis means geometric nonlinearity and material nonlinearity and complex nonlinearity analysis considers both of them. In this study, nonlinear equation of equilibrium considering geometric nonlinearity as per finite element method was applied and also considered the material nonlinearity using the relation of stress-strain in element. It is applied to find unstable result for tracing load-deflection curve in the numerical analysis tech. especially Arc-length method, and result of the analysis was studied by ABAQUS a general purpose of the finite element program. It is found that the present analysis predicts accurate nonlinear behavior of plane and space truss.

• Korean Journal of Social Welfare
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• v.38
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• pp.284-308
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• 1999

This study is about the nationwide research concerning the degree and trends of marital conflict and instability. The research samples are 1,217 married. As the result of the research, the most conflict able issues in Korean couples are on the husband-wife relations, such as habitual differences, sharing in houseworks, conflicts in the role expectation, and the communication problems. In this study, We devide the marital relationships into 4 types (A, B, C, and D) in the view of the satisfaction & instability of marriage. First, the marriage with unsatisfaction and instability (A) was portioned 8.3%, and the satisfactory & stable type (D) was portioned 68.4%. It seems the marital relationships in Korea are relatively stable. However, the portion of type B-unsatisfactory, but stable couples-is 17.1% and the type C-satisfactory, but unstable marriage 6.2%. The result implies that the indication of marital instability should consider not only the divorce rate, but also the quality of marital relationships. In other words, the intervention for the conflict couples yet not divorce is needed. The differences of conflict areas among the relational types is not so much, but the degrees on conflicts are very serious. Especially, in the areas of marital conflict, love issues and personal value system affect the division of relational types of marriage most. It means the interaction factors are the most important variables about maintaining the marital relations with stable and satisfaction.

• Geophysics and Geophysical Exploration
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• v.11 no.2
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• pp.153-160
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• 2008

Seismic modeling is used to simulate wave propagation in the earth. Although the earth's subsurface is usually semi-infinite, we cannot handle the semi-infinite model in seismic modeling because of limited computational resources. For this reason, we usually assume a finite-sized model in seismic modeling. In that case, we need to eliminate the edge reflections arising from the artificial boundaries introducing a proper boundary condition. In this study, we changed three kinds of boundary conditions (sponge boundary condition, Clayton and Engquist's absorbing boundary condition, and Higdon's transparent boundary condition) so that they can be applied in elastic wave modeling for anisotropic media. We then apply them to several models whose Poisson's ratios are different. Clayton and Engquist's absorbing boundary condition is unstable in both isotropic and anisotropic media, when Poisson's ratio is large. This indicates that the absorbing boundary condition can be applied in anisotropic media restrictively. Although the sponge boundary condition yields good results for both isotropic and anisotropic media, it requires too much computational memory and time. On the other hand, Higdon's transparent boundary condition is not only inexpensive, but also reduce reflections over a wide range of incident angles. We think that Higdon's transparent boundary condition can be a method of choice for anisotropic media, where Poisson's ratio is large.