• Communications for Statistical Applications and Methods
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• 제16권3호
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• pp.519-528
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• 2009

This paper deals with nonparametric estimation of discontinuous regression curve. Quite number of researches about this topic have been done. These researches are classified into two categories, the indirect approach and direct approach. The major goal of the indirect approach is to obtain good estimates of jump locations, whereas the major goal of the direct approach is to obtain overall good estimate of the regression curve. Thus it seems that two approaches are quite different in nature, so people say that the comparison of two approaches does not make much sense. Therefore, a thorough comparison of them is lacking. However, even though the main issue of the indirect approach is the estimation of jump locations, it is too obvious that we have an estimate of regression curve as the subsidiary result. The point is whether the subsidiary result of the indirect approach is as good as the main result of the direct approach. The performance of two approaches is compared through a simulation study and it turns out that the indirect approach is a very competitive tool for estimating discontinuous regression curve itself.

• 보건행정학회지
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• 제17권3호
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• pp.106-128
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• 2007

The Korean health care system is under great controversy. Over the last 30 years, main goal of health policies was to pursue equal access of health care services. However, another goal of health policies laid on efficiency and Quality of care, it had lower priorities. Superficially, controversy stems from priority setting among goals of health care system, equity, efficiency and quality. At a deeper level, arguments arise from disagreement and confusion about the values of Korean health care system. One of the value spectrums believes that health care is the basic right of human beings, therefore it should be produced and distributed on need approach, and needs are known to be decided by professionals. If we accept need approach, health care is a pubic good. Another value of spectrums considers that health care should be distributed on demand approach. Demand approach means that health care is a consumption good on the positive economics, while normative judgement believes that health care is a public good. In equity aspect, health care is considered as a public good. Over the last several years, some of scholars proposed health care reform based on the principle of competition which is based on demand approach. Others argue that the competition principle based on demand approach is not appropriate for the reform proposal, because health care has to be approached on need base. If we do not make explicit values we should adopt, consensus building for reform is nearly impossible. From this perspective, this article will review an ideology and reality in health policies in Korea.

• 대한족부족관절학회지
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• 제17권4호
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• pp.257-263
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• 2013

Open reduction and internal fixation is currently considered as a gold standard of treatment in most of the intra-articular calcaneal fractures. Among various different approaches, extensile lateral approach is the most popular since it provides good exposure to the subtalar joint. However, wide skin incision followed by extensive soft tissue dissection leading to increased risk of wound breakdown is the most serious drawback. Sinus tarsi approach, a minimal invasive technique to approach the subtalar joint and reduce the intra-articular calcaneal fractures, provides good clinical outcome and less wound complications compared to the extensile lateral approach. This article introduces the surgical technique and review of the literature regarding the sinus tarsi approach.

• 응용통계연구
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• 제23권6호
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• pp.1245-1253
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• 2010

There are two main approaches for estimating the discontinuous regression function nonparametrically. One is the direct approach, the other is the indirect approach. The major goal of the two approaches are different. The direct approach focuses on the overall good estimation of the regression function itself, whereas the indirect approach focuses on the good estimation of jump locations. Apparently, the two approaches are quite different in nature. Gijbels et al. (2007) argue that the comparison of two approaches does not make much sense and that it is even difficult to choose an appropriate criterion for comparisons. However, it is obvious that the indirect approach also has the regression curve estimate as the subsidiary result. Therefore it is necessary to verify the appropriateness of the indirect approach as the estimator of the discontinuous regression function itself. Park (2009a) compared the performance of two approaches through a simulation study. In this paper, we consider a more general case and draw some useful conclusions.

• Journal of Korean Neurosurgical Society
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• 제39권1호
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• pp.26-31
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• 2006

Objective : The authors study on the clinical presentations and the surgical outcomes of the tumors in the ventricular system. Methods : 15 patients with ventricular tumor were studied. The clinical presentation, radiological findings, different surgical approaches, and outcome were analyzed. Tumors were classified into three groups based on their locations in MRI : lateral, third and fourth ventricle. Surgical methods were transcortical approach in eight patients, transcallosal approach in four, median suboccipital approach in two, and subfrontal approach in one. Gross total removal was achieved in 10 patients. Subtotal resections were performed in the rest. Glasgow outcome scale was used for evaluation of the surgical outcome. Results : Main clinical presentations were chronic headache in patients with the tumor in the lateral ventricular tumor and sudden onset of headache and consciousness change in patients with the tumor in the third and fourth ventricular tumor Development of hydrocephalus was more predominant in patients with the tumors in the third ventricle. Postoperatively, good outcome [Glasgow outcome scale IV, V] were in 73%, and better results was observed in patients with the tumors in the lateral ventricular tumor. The differences of outcome according to surgical approach were not recognized, even though it was not reliable statistically. Conclusion : In ventricular tumor, postoperative outcome is not good in patients with sudden development of headache, hydrocephalus, high grade tumor. Outcome is good in patients with the tumor in the lateral ventricle relatively. There is no difference in outcome according to the approach method to the tumors. And it is necessary to be aware of various approach methods to the tumors and anatomy surrounding the ventricle for avoidance of neurological complications.

• 한국생산제조학회지
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• 제24권5호
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• pp.535-540
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• 2015

We propose an enhanced Green's function approach to predict thermal stresses by considering temperature-dependent material properties. We introduce three correction factors for the maximum stress, the time taken to reach maximum stress, and the time required to attain steady state based on the Green's function results for each temperature. The proposed approach considers temperature-dependent material properties using correction factors, which are defined as polynomial expressions with respect to temperatures based on Green's functions, that we obtain from finite-element (FE) analyses at each temperature. We verify the proposed approach by performing detailed FE analyses on thermal transients. The Green's functions predicted by the proposed approach are in good agreement with those obtained from FE analyses for all temperatures. Moreover, the thermal stresses predicted using the proposed approach are also in good agreement with the FE results, and the proposed approach provides better predictions than the conventional Green's function approach using constant, time-independent material properties.

• Archives of Plastic Surgery
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• 제35권2호
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• pp.152-158
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• 2008

Purpose: Mandibulotomy approach and mandible sparing approach are most common methods for oropharyngeal cancer surgery. Good surgical view and convenience of flap inset are advantages of mandibulotomy approach but deformity of mandible contour, postoperative malocclusion and radionecrosis are its limitations. To make up for the limitations, mandible sparing method is commonly performed, but limited surgical view and difficulties of flap inset are the weak points of this approach. The purpose of the study is to compare mandibulotomy and mandible sparing approaches in postoperative complications and progression of the treatment in oropharyngeal cancer operation and reconstruction. Methods: Single reconstructive microsurgeon operated for oropharyngeal cancer patients with different surgeons of head and neck department who prefer mandibulotomy and mandible sparing approach respectively, and we compared the frequency of postoperative complication, operation time, duration of hospitalization and recurrence rate between two different surgical approaches. Results: Mandibulotomy approach was used in 18 patients and mandible sparing approach was used in 15 patients. In mandibulotomy approach, there happened one case of teeth injury and one case of necrosis of skin and gingiva, but there happened no malocclusion and radionecrosis. In mandible sparing approach, there were 3 cases of fistula and 2 cases of infection which are significantly higher than mandibulotomy approach. There were no significant differences between early regional recurrence and duration of hospitalization. Conclusion: In this study we compared two different methods for the surgical approach in oropharyngeal cancer surgery. As mandible sparing approach has difficulties of limited surgical view, it can be used for the limited indications of anterior tongue and mouth floor cancer. Mandibulotomy approach has advantages of good surgical view and convenience of flap inset. In this method preservation of gingival tissue, watertight fashion suture, delicate osteotomy and plate fixation to maintain occlusion are the key points for the successful results.

• Communications for Statistical Applications and Methods
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• 제17권3호
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• pp.309-318
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• 2010

The construction of asymptotic confidence intervals is considered for the difference of binomial proportions in two doubly sampled data subject to false-positive error. The coverage behaviors of several likelihood based confidence intervals and a Bayesian confidence interval are examined. It is shown that a hierarchical Bayesian approach gives a confidence interval with good frequentist properties. Confidence interval based on the Rao score is also shown to have good performance in terms of coverage probability. However, the Wald confidence interval covers true value less often than nominal level.

• Journal of Power Electronics
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• 제9권5호
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• pp.757-771
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• 2009

This paper proposes a systematic approach to the modeling of the small-signal characteristics of three-phase bridge boost rectifiers under non-sinusoidal conditions. The main obstacle to the conventional synchronous d-q frame modeling approach is that it is unable to identify a steady-state under non-sinusoidal conditions. However, for most applications under non-sinusoidal conditions, the current loops of boost rectifiers are designed to have a bandwidth that is much higher than typical harmonics frequencies in order to achieve good current control for these harmonic components. Therefore a quasi-static method is applied to the proposed modeling approach. The converter small-signal characteristics developed from conventional synchronous frame modeling under different operating points are investigated and a worst case point is then located for the current loop design. Both qualitative and quantitative analyses are presented. It is observed that operating points influence the converter low frequency characteristics but hardly affect the dominant poles. The relationship between power stage parameters, system poles and zeroes is also presented which offers good support for the system design. Both the simulation and experimental results verified the analysis and proposed modeling approach. Finally, the practical case of a parallel active power filter is studied to present the modeling approach and the resultant regulator design procedure. The system performance further verifies the whole analysis.

• Journal of Korean Neurosurgical Society
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• 제37권6호
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• pp.399-404
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• 2005

Objective: Aneurysms arising from the posterior inferior cerebellar artery(PICA) are uncommon. We review literature on that and surgical results on aneurysmal treatment by choice of surgical approach. Methods: On the basis of radiologic findings & charts, we review retrospectively the surgical results of 12 cases from Mar 1999 to Dec 2003. Results: The mean age of the 12 patients was 55.8(ranged from 36 to 71) and female was predominant (female:male = 8:4). Locations of PICA aneurysms revealed variously(vertebral artery - PICA junction: 8, lateral medullary segment: 2, PICA - anterior inferior cerebellar artery common trunk: 1, telovelomedullary : 1). Surgical approaches & treatments were attempted in 11 cases and embolization was done in 1 case(Far lateral transcondylar or supracondylar approach & clipping: 9, Far lateral transcondylar or supracondylar approach and trapping: 2, suboccipital approach & clipping: 1). The surgical result were 8 of 12 patients were good outcome, 1 of 12 was severely disabled and 3 of 12 were died. Conclusion: First, we choose surgical approach by the laterality of aneurysms and surgical or interventional treatment is attempted as soon as possible. The PICA aneurysm is regarded as having a relatively good surgical outcome without drilling of the posterior arch of the atlas.