• Quality Improvement in Health Care
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• v.12 no.2
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• pp.75-83
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• 2006

Background : Utilization review has been adopted as a vehicle for cost and utilization control of health care services. Its role was further stressed and expanded through the establishment of Health Insurance Review Agency in 2001. This article is to introduce concept, activities, and effect of utilization review based on the experiences of U.S. and to suggest important characteristics for ideal utilization review activities at the national level in Korea. Method : Twenty-five articles related with utilization review were reviewed after being selected through web site search through Med Line and Richis. Result : Utilization review was introduced mainly for health care expenditure control either by insurer, provider or the third parties under the pressure of increasing health care cost. It's activities can be categorized to prospective, concurrent and retrospective review according to the time of service provision. Based on most of studies, utilization review has been effective in controling rising health care cost and utilization. However it's effectiveness assumes a reimbursement structure of managed care like capitation payment. More worse, it is still unknown it's effectiveness on quality of care. Conclusion : Utilization review should be employed to increase the cost effectiveness of medical care by optimizing quality and patient's outcomes while also attempting to reduce the use of resources. So, it should consider outcomes before expenditures, check for both under and over-use, and construct an structure in which consumption is reduced equitably. Aggressive adoption of utilization review in Korean health care setting with fee-for-service reimbursement structure might not be a cost-effective approach before adoption of prospective payment system such as D.R.G. and capitation.

• 한국전산유체공학회:학술대회논문집
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• 2009.11a
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• pp.13-18
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• 2009

Flight vehicles such as wheel wells and bomb bays have many cavities. The flow around a cavity is characterized as an unsteady flow because of the formation and dissipation of vortices brought about by the interaction between the free stream shear layer and the internal flow of the cavity. The resonance phenomena can damage the structures around the cavity and negatively affect the aerodynamic performance and stability of the vehicle. In this study, a numerical analysis was performed for the cavity flows using the unsteady compressible three-dimensional Reynolds-Averaged Navier-Stokes (RANS) equation with Wilcox's turbulence model. The Message Passing Interface (MPI) parallelized code was used for the calculations by PC-cluster. The cavity has aspect ratios (L/D) of 2.5 ~ 7.5 with width ratios (W/D) of 2 ~ 4. The Mach and Reynolds numbers are 0.4 ~ 0.6 and $1.6{\times}106$, respectively. The occurrence of oscillation is observed in the "shear layer and transient mode" with a feedback mechanism. Based on the Sound Pressure Level (SPL) analysis of the pressure variation at the cavity trailing edge, the dominant frequencies are analyzed and compared with the results of Rossiter's formula. The dominant frequencies are very similar to the result of Rossiter's formula and other experimental data in the low aspect ratio cavity (L/D = ~ 4.5). In the large aspect ratio cavity, however, there are other low dominant frequencies due to the leading edge shear layer with the dominant frequencies of the feedback mechanism. The characteristics of the acoustic wave propagation are analyzed using the Correlation of Pressure Distribution (CPD).

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.63-63
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• 2003

In an effort to uncover the spermatogenic impairment by the polychlorinated biphenyls (PCBs), the expression of tight junctions (TJs) genes important for the formation of the blood testis barrier (BTB) were examined following the 3,3',4,4',5-pentachloro biphenyl (PCB126) treatment in cultured neonatal testis in mice. At 4 days (D4) after 10 and 100 nM PCB126 treatment the expression of claudin-11 was significantly increased when compared with vehicle control. In contrast no difference in occludin and claudin-1 expression was found among the experimental group. On D8, 100 nM PCB126 significantly increased the expression of claudin-11 but not occludin and claudin-1. 1 uM PCB126 treatment significantly decreased expressions of occludin and ciaudin -1, suggesting the general toxic effect on the Sertoli cell. Because PCB126 does not alter the proliferative activity of spermatogenic cells and Sertoli cells in neonatal testis, it is likely that increase in the expression of claudin-11 by low dose of PCB126 may attribute to the alteration of the Sertoli cells differentiation in testis. It also emphasized that PCB126 might have differentially affected the transcription of TJ genes in Sertoli cells. In conclusion, this result suggests that the structure of TJ may be targeted by PCB126 in neonatal testis in mice and that co-PCB is potentially harmful to spermatogenesis by alteration of the development of BTB.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.1
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• pp.105-111
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• 2010

In the field of 'Human Vibration', it has been interested subjects to make equal sensation curves related to translational and rotational direction of whole-body, hand-transmitted and head-transmitted vibration, etc. When we consider the vibration of a vehicle, the main factor is vertical whole-body vibration. Until now, most of equal sensation curves used to derive frequency weighting function had been made using Western people. However, because of the inherent differences (for example, characteristic and shape of body parts, muscular and cellular tissue) between the Western people and the Oriental people, equal sensation curves based on Oriental people might be required. Also, the weight differences between the samples which consist of average-weighted and over-weighted group might cause the difference of equal sensation curves. So, in this study, 20 male Korean people were used to find equal sensation curves subject to vertical whole-body vibration on seated posture. Among 20 males, an over weighted group consisted of 10 male persons and an average weighted group was the others. Integrating and analyzing the data of two groups, some of non-parametric tests such as 'The Wilcoxon Signed Rank Test' and 'The Mann Whitney U test' were used.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.6
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• pp.87-93
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• 2007

It is complicate to analysis the systems, dual mode hybrid systems, because they are composed of many planetary gear sets. For the performance test, it needs to define the systems with representative parameters. In this paper, system parameters, $\alpha$, $\beta$, $\zeta$, are introduced to define the systems, and an arbitrary system like E-IVT developed by Renault Motors is converted to the general system having equivalent parameters, such as $\beta'$, $R'_b$. Pontryagin principle and Kuhn-Tucker condition method are applied to solve the constrained problems, by which the methodology for accelerating test is generalized, and the results of the simulation are reported. In addition, the effects of alternative strategies are mentioned. The method of fuel economy test at engine mode is also introduced. The results of test at engine mode is different from the results of optimal trajectory, but the fuel economy of the engine mode is related to the highway driving and optimized operating of the system.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.9
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• pp.787-797
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• 2011

The noise in a vehicle is an important factor for customers purchasing a car. Particularly, reduction of the noise that is generated from HVAC(heating, ventilation and air conditioning) is very important since it has considerable effects on interior noise. In general, identification of noise source is crucial to reduce noise level. The complex acoustic intensity method is widely used to obtain the accurate measurement and identification of noise source. Therefore, in the previous study, noise source of HVAC was identified through experimental approach using the complex acoustic intensity method. In this study, we are intended to confirm reduced level of noise by comparing the result between before and after modification of cam curve that is based on identified noise source of HVAC. It is found out that noise source of HVAC are motor and cam area using the complex acoustic intensity method in the previous study. We performed experiments to compare noise level between before and after modification of cam curve. Especially, it can be seen that complex acoustic intensity method using both active and reactive intensity is vital in devising a strategy for comparison to noise level. Also, the vector flow of acoustic intensity was investigated to identify sound intensity distributions and energy flow in the near field of HVAC.

• Journal of Oriental Neuropsychiatry
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• v.14 no.1
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• pp.27-44
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• 2003

Objective : The aim of this study was to assess protective effects of Whangryonhaedoktang on the chronic mild stress (CMS) animal model of depression. Method : Male Sprague-Dawley rats were used for this study. The subjects were divided into 3 groups (CMS-drug group: Whangryonhaedoktang was administered during CMS procedure, CMS-vehicle: water was administered during CMS procedure, normal control group: without CMS procedure). After 4 weeks of CMS procedure, Morris water maze (MWM) test and open field test were executed and tyrosine hydroxylase (TH) was measured in ventral tegmental area (VTA) and locus coeruleus (LC) of rat brain. Result : 1. CMS procedure induced defects of spatial learning in early period of MWM test. 2. CMS Whangryonhaedoktang group showed shorter escape latency in comparison with CMS control group in MWM test on the first day of the test. 3. CMS Whangryonhaedoktang group and CMS control group showed no significant difference of activities and emotional behaviors in comparison with normal control group in open field test. 4. CMS Whangryonhaedoktang group showed significant inhibition effects of TH expression in VTA and LC areas in comparison with CMS control group. Conclusion : These results suggest that Whangryonhaedoktang may have inhibition effects to early period defects of spatial learning and protective antidepressant effects in CMS model rats.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.6
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• pp.635-642
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• 2004

In electric motor coaches. the rolling stocks move by the adhesive effort between rail and driving wheel. Generally, the adhesive effort is defined by the function of both the weight of electric motor coach and the adhesive effort between rails and driving wheel. The characteristics of adhesive effort is strongly affected by the conditions between rails and driving wheel. When the adhesive effort decreases suddenly, the electric motor coach has slip phenomena. This paper proposes a re-adhesion control based on disturbance observer and sensor-less vector control. The numerical simulation and experimental results point out that the proposed readhesion control system has the desired driving wheel torque response for the tested bogie system of electric coach. Based on this estimated adhesive effort, the re-adhesion control is performed to obtain the maximum transfer of the tractive effort.

• Journal of Environmental Health Sciences
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• v.33 no.5
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• pp.379-385
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• 2007

This study was aimed to investigate the estrogenic activity of Di-(2-ethylhexyl) adipate (DEHA) using immatured type uterotrophic assay. SD rats were treated with DEHA (40, 200, 1000mg/kg/day), estradiol-3-benzoate (EB) $(1{\mu}g/kg/day)$ as positive control on the assay. In immatured-type uterotrophic assay, relative organ weights of kidney and reproductive organs such as ovary at high-dose group were significantly increased compared to those of vehicle control group. DEHA did not influence the levels of serum FSH and LH, and uterine morphological changes such as luminal epithelial height, myometrial thickness and numbers of uterine gland, and BrdU indices. In these results, there was no significant variation by DEHA treatment, suggesting that DEHA appears not to be a endocrine disrupter with estrogenic activity.

• The Transactions of the Korea Information Processing Society
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• v.3 no.5
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• pp.1070-1081
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• 1996

In this research, a model was developed for estimating the queue length of vehicles, based on occupancy time of each vehicle collected by loop detectors which were setup at the upstream of urban street. The estimation model suggestes a method which minimizes architectural effects of the street, such as existence of pedestrian crossing, for future applications to the field. The estimation model suggested in this research was established based on real traffic data collected at up-stream detectors in Kangnam Subway station, Seoul, and the formula of the model is based on Multi-Polynomial equations. Consequence of the experiments showed that the model can adequately and in real-time mode measure length of the queue which were constructed at the 80 to 90 meters away from the upstream detectors. The estimation accuracy of the model was verified in statistical analysis conducted by regressing analysis and test results in real traffic situation.