• Journal of the Korean Statistical Society
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• v.29 no.2
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• pp.137-153
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• 2000

Conjoint analysis is a widely-used statistical technique for measuring relative importance that individual place on the product's attributes. Despsite its practical importance, the complexity of conjoint model makes it difficult to analyze. In this paper, w consider a Bayesian approach using Jeffrey's noninformative prior. We derive Jeffrey's prior and give a sufficient condition under which the posterior derived from the Jeffrey's prior is paper.

• Journal of the Korean Statistical Society
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• v.19 no.2
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• pp.145-150
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• 1990

In this article we develop the marginal posterior density of the model parameters in the multiresponse regression models when missing values exist only in one response. The resulting density resolves a couple of problems in the estimation approach proposed by Box, Draper, and Hunter (1970) and provides a general interpretation for relationship between the estimates of the missing values and the parameters.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.12 no.3
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• pp.74-80
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• 1990

This is to report a case of surgical and orthodontic of posterior scissor bite, deep bite and gummy smile by the segmental osteotomies. The surgical thechnics procedures used are Peterson's mandibular posterior segmental osteotomy, modified $K{\ddot{o}}le$ technic for mandibular anterior segment and Wunderer's maxillary anterior segmental osteotomy. The results are as follows : 1) Peterson's mandibular posterior segmental osteotomy could be achieved by the buccal approach with some difficulties in accessbility. 2) Upper and lower anterior segmental osteotomies were followed separately to correct the deep curve of Spee, deep bite and gummy smile in shortened period. 3) All alveolar segments were immobilized in preplanned position by the prefabricated palatal and lingual resin splint, therefore intermaxillary fixation was not necessary.

• The Korean Journal of Applied Statistics
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• v.15 no.1
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• pp.73-84
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• 2002

Linear regression models with inequality constraints on the coefficients are frequently used in economic models due to sign or order constraints on the coefficients. In this paper, we propose a Bayesian approach to selecting significant explanatory variables in linear regression models with inequality constraints on the coefficients. Bayesian variable selection requires computation of posterior probability of each candidate model. We propose a method which computes all the necessary posterior model probabilities simultaneously. In specific, we obtain posterior samples form the most general model via Gibbs sampling algorithm (Gelfand and Smith, 1990) and compute the posterior probabilities by using the samples. A real example is given to illustrate the method.

• Korean Journal of Radiology
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• v.23 no.9
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• pp.901-910
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• 2022

Objective: This study aimed to assess the technical feasibility, efficacy, and safety of the safe triangular working zone (STWZ) approach applied in percutaneous vertebroplasty (PV) for spinal metastases involving the posterior part of the vertebral body. Materials and Methods: We prospectively enrolled 87 patients who underwent PV for spinal metastasis involving the posterior part of the vertebral body, with or without the STWZ approach, from January 2019 to April 2022. Forty-nine patients (27 females and 22 males; mean age ± standard deviation [SD], 57.2 ± 11.6 years; age range, 31-76 years) were included in group A (with STWZ approach), accounting for 54 vertebrae. Thirty-eight patients (18 females and 20 males; 59.1 ± 10.9 years; 29-81 years) were included in group B (without STWZ approach), accounting for 57 vertebrae. Patient demographics, procedure-related variables, and pain relief as assessed using the visual analog scale (VAS) were collected at different time points. Tumor recurrence in the vertebrae after PV was analyzed using Kaplan-Meier curves. Results: The STWZ approach was successful from T1 to L5 without severe complications. Cement filling was satisfactory in 47/54 (87.0%) and 25/57 (43.9%) vertebrae in groups A and B, respectively (p < 0.001). Cement leakage was not significantly different between groups A and B (p = 1.000). Mean VAS score ± SD before and 1 week and 1, 3, 6, 9, and 12 months after PV were 7.6 ± 1.8, 4.2 ± 2.0, 2.7 ± 1.9, 1.9 ± 1.5, 1.7 ± 1.4, 1.7 ± 1.1, and 1.6 ± 1.3, respectively, in group A and 7.2 ± 1.7, 4.0 ± 1.3, 3.4 ± 1.6, 2.4 ± 1.2, 1.8 ± 1.0, 1.4 ± 0.5, and 1.7 ± 0.9, respectively, in group B. Kaplan-Meier analysis showed a lower tumor recurrence rate in group A than in group B (p = 0.001). Conclusion: The STWZ approach may represent a new, safe, alternative/auxiliary approach to target the posterior part of the vertebral body in the PV for spinal metastases.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.23 no.4
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• pp.338-347
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• 2001

Purpose: This is to review the cases of posterior maxillary segmental osteotomies to regain the interarch spaces for dental implants in the posterior mandible. Materials & Methods: Seven patients who presented with alveolar extrusion of upper posterior molars underwent segmental osteotomies by single-stage Kufner's buccal approach under the intravenous sedation and local anesthesia. The posterior maxillary cento-alveolar segments were repositioned upward using pre-fabricated palato-occlusal resin splints and immobilized with osteosynthesis microplates and screws. Dental implants were installated simultaneously. The regained spaces, tooth vitality, periodontal healing, relapse, tenderness on function, and complications including maxillary sinus involvements were evaluated periodically for over one year after the surgeries. Results: The single-tage procedures were completed within 80 minutes without any surgical complications. The posterior maxillary segments were repositioned upward to regain the interarch spaces ranging from 2.5 to 5.5mm. All teeth involved in the procedures keep their vitalities. The repositioned segments were maintained showing neither evidence of periodontal break-down nor tenderness to function. One patient whose segments had not been immobilized by osteosynthesis plate resulted in 2mm down-ward relapse in post-operative 8 months. A case of postoperative nasal bleeding from the posterior-lateral wall resulted in oroantral fistula and chronic maxillary sinusitis later. Conclusion: The extruded dento-alveolar segments of the posterior maxilla were repositioned properly by Kufner's one-stage segmental osteotomies. One microplate can be of help to keep the position until the osseous healing enough to support the masticatory force.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.15 no.3
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• pp.171-177
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• 1993

The prominent malar region has been recognized a sign of youth and beauty in caucasian who generally have a dolichocephalic and long face. But in the orients, especially Koreans who generally have a mesocephalic or brachycephalic face, it is considered an agressive, unesthetic facial appearance. So many patients require the shaving of prominent malar eminence and arch, and many methods of its reduction have been devised. For the exposure of malar complex, infraorbital skin incision, intraoral approach, preauricular approach, supraauricular scalp incision, and coronal approach have been used. And for the reduction of bony structure, direct shaving, contouring and repositioning of the malar complex after extirpation, and medially fracture of zygomatic arch have been used with its own merits. We performed the reduction malarplasty through intraoral approach. After two parallel oeteotomy at medial part of the zygomatic bone, the midsegment is removed. The posterior arch of zygoma was bended or green stick fractured. When more correction was required, the posterior arch was fractured medially through the step incision at skin. This method has a some advantages. Compared with the method for extirpation of malar complex, the infection rate is diminished, the resorption is small because of no free bone graft. And cheek drooping is prevented. Compared with the method of coronal approach, the surgical trauma is minimal. Now we report some cases of reduction malarplasty performed through intraoral approach and disscus the surgical technique and results.

• Atmosphere
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• v.18 no.2
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• pp.111-120
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• 2008

This study presents a change-point in the 30 years (1976-2005) time series of the annual and the heavy precipitation characteristics (amount, days and intensity) averaged over South Korea using Bayesian approach. The criterion for the heavy precipitation used in this study is 80 mm/day. Using non-informative priors, the exact Bayes estimators of parameters and unknown change-point are obtained. Also, the posterior probability and 90% highest posterior density credible intervals for the mean differences between before and after the change-point are examined. The results show that a single change-point in the precipitation intensity and the heavy precipitation characteristics has occurred around 1996. As the results, the precipitation intensity and heavy precipitation characteristics have clearly increased after the change-point. However, the annual precipitation amount and days show a statistically insignificant single change-point model. These results are consistent with earlier works based on a simple linear regression model.

• ETRI Journal
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• v.27 no.4
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• pp.461-464
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• 2005

Recently, a variety of confidence measures for utterance verification has been studied to improve speech recognition performance by rejecting out-of-vocabulary inputs. Most of the conventional confidence measures for utterance verification are based primarily on hypothesis testing or an approximated posterior probability, and their performances depend on the robustness of an alternative hypothesis or the prior probability. We introduce a novel confidence measure called a search confusion rate (SCR), which does not require an alternative hypothesis or the approximation of posterior probability. Our confusion-based approach shows better performance in additive noise-corrupted speech as well as in clean speech.

• Journal of the Korean Society of Safety
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• v.36 no.2
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• pp.32-38
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• 2021

This paper suggests an approach to evaluate the reliability of an intelligent power module with information deficiency of prior distribution and the characteristics of censored data through Bayesian statistics. This approach used a prior distribution of Bayesian statistics using the lifetime information provided by the manufacturer and compared and evaluated diffuse prior (vague prior) distributions. To overcome the computational complexity of Bayesian posterior distribution, it was computed with Gibbs sampling in the Monte Carlo simulation method. As a result, the standard deviation of the prior distribution developed using simple information was smaller than that of the posterior distribution calculated with the diffuse prior. In addition, it showed excellent error characteristics on RMSE compared with the Kaplan-Meier method.