• 한국자동차공학회논문집
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• 제13권5호
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• pp.163-170
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• 2005

Urban transit is a complex system that is combined electrically and mechanically, it is necessary to construct maintenance system for securing safety accompanying high-speed driving and maintaining promptly. Expert system is a computer program which uses numerical or non-numerical domain-specific knowledge to solve problems. In this research, we intend to develop the expert system which diagnose failure causes quickly and display measures. For the development of expert system, standardization of failure code classification system and creation of BOM(Bill Of Materials) have been first performed. Through the analysis of failure history and maintenance manuals, knowledge base has been constructed. Also, for retrieving the procedure of failure diagnosis and repair linking with the knowledge base, we have built RBR(Rule Based Reasoning) engine by pattern matching technique and CBR(Case Based Reasoning) engine by similarity search method. This system has been developed based on web to maximize the accessibility.

• 한국기계가공학회지
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• 제19권9호
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• pp.47-52
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• 2020

With the 4th industrial revolution, condition monitoring using machine learning techniques has become popular among researchers. An overload due to complex operations causes several irregularities in MOSFETs. This study investigated the acquired voltage to analyze the overcurrent effects on MOSFETs using a failure mode effect analysis (FMEA). The results indicated that the voltage pattern changes greatly when the current is beyond the threshold value. Several features were extracted from the collected voltage signals that indicate the health state of a switched-mode power supply (SMPS). Then, the data were reduced to a smaller sample space by using a principal component analysis (PCA). A robust machine learning algorithm, the support vector machine (SVM), was used to classify different health states of an SMPS, and the classification results are presented for different parameters. An SVM approach assisted by a PCA algorithm provides a strong fault diagnosis framework for an SMPS.

• 대한기계학회논문집A
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• 제30권5호
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• pp.520-527
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• 2006

The design of major industrial facilities for the prevention of fatigue failure is customarily done by defining a set of transients and performing a calculation of cumulative usage factor. However, sometimes, the inherent conservatism or lack of details as well as unanticipated transients in old plant may cause maintenance problems. Even though several famous on-line monitoring and diagnosis systems have been developed world-widely, in this paper, a new system fur fatigue monitoring and life evaluation of crane is proposed to reduce customizing effort and purchasing cost. With regard to the system, at first, comprehensive operating transient data has been acquired at critical locations of crane. The real-time data were classified, by using adaptive resonance theory that is one of typical artificial neural network, into representative stress groups. Then the each classified stress pattern was mapped to calculated cumulative usage factor in accordance with ASME procedure. Thereby, promising results were obtained fur the crane and it is believed that the developed system can be applicable to other major facilities extensively.

• 한국멀티미디어학회논문지
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• 제24권11호
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• pp.1461-1471
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• 2021

This paper presents a light exposure correction algorithm for less pleasant images, acquired with a light metering failure. Since conventional tone mapping and gamma correction methods adopt a function mapping with the same range of input and output, the results are pleasurable for almost symmetric distributions to their intensity average. However, their corrections gave insufficient outputs for asymmetric cases at either bright or dark regions. Also, histogram modification approaches show good results on varied pattern images, but these generate unintentional noises at flat regions because of the compulsive shift of the intensity distribution. Therefore, in order to sufficient corrections for both bright and dark areas, the proposed algorithm calculates the gamma coefficients using primary parameters extracted from the global distribution. And the fusion weights are adaptively determined with complementary parameters, considering the classification information of a binary segmentation. As the result, the proposed algorithm can obtain a good output about both the symmetric and the asymmetric distribution images even with severe exposure values.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(5)
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• pp.293-296
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• 2002

In this study, the object is a development on uroflowmetry system to detect a voiding symptom conveniently in home or hospital. The hardware was composed of mechanism and system circuit part, the software was divided into firmware and PC program part. The following experiment was performed to evaluate an ability of classification and fitness. First, the following parameters was calculated in each flow curve pattern. The parameters are MFR, AFR, VOL, VT, FT, and TMF. A significant difference among parameters was examined through a statistical analysis for extracted parameters between normal and abnormal group. In the next work, the following experimentation was performed to classify the voiding symptom. Analysis of congregate rate was examined to find out classification possibility about each symptom of BPH, voiding difficulty, detrusor failure and hyperreflexia, unstable bladder. The uroflow data with the above symptom was divided into normal and abnormal group using fuzzy classifier. and that was performed appending the other group again. Fuzzy classification result using MFR and AFR was superior by 89.6 % more than grouping evaluation including VOL.

• 한국통신학회논문지
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• 제31권11B호
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• pp.987-996
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• 2006

본 논문에서는 NEMO 환경에서 핸드오버를 통해 발생할 수 있는 이동 시나리오의 정의와 핸드오버 실패시의 지연 및 패킷 손실과 전송비용의 분석을 목적으로 한다. 이를 위해 네트워크 노드의 이동성을 지원하며 핸드오버 절차의 성능향상을 위한 메커니즘 중 하나인 빠른 핸드오버 (FMIPv6)와 계층적 이동 IPv6 구조 (HMIPv6)가 NEMO와 결합했을 때 발생할 수 있는 네트워크 개체의 다양한 이동 시나리오를 분류하고, 각 시나리오에서의 핸드오버 실패의 경우를, 빠른 핸드오버 절차에 기반한 시점을 기준으로 정의하였으며 이동 네트워크 개체의 핸드오버가 실패했을 경우 절차를 완료하는데 필요한 지연 및 그 시간 동안의 패킷 손실과 전송비용 측면에서 분석했다.

• Radiation Oncology Journal
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• 제30권4호
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• pp.205-212
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• 2012

Purpose: To evaluate the effect of pelvic radiotherapy (RT) in patients with stage IV rectal cancer treated with resection of primary tumor with or without metastasectomy. Materials and Methods: Medical records of 112 patients with stage IV rectal cancer treated with resection of primary tumor between 1990 and 2011 were retrospectively reviewed. Fifty-nine patients received synchronous or staged metastasectomy whereas fifty-three patients did not. Twenty-six patients received pelvic radiotherapy. Results: Median overall survival (OS), locoregional recurrence-free survival (LRFS), and progression-free survival (PFS) of all patients was 27, 70, and 11 months, respectively. Pathologic T (pT), N (pN) classification and complete metastasectomy were statistically significant factors in OS (p = 0.040, 0.020, and 0.002, respectively). RT did not improve OS or LRFS. There were no significant factors in LRFS. pT and pN classification were also significant prognostic factors in PFS (p = 0.010 and p = 0.033, respectively). In the subgroup analysis, RT improved LRFS in patients with pT4 disease (p = 0.026). The locoregional failure rate of the RT group and the non-RT group were 23.1% and 33.7%, showing no difference in the failure pattern of both groups (p = 0.260). Conclusion: Postoperative pelvic RT did not improve LRFS of all metastatic rectal cancer patients; however, it can be recommended to patients with pT4 disease. A complete resection of metastatic masses should be performed if possible.

• 약학회지
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• 제58권1호
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• pp.71-79
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• 2014

Although Korean patients with type 2 diabetes mellitus (T2DM) are generally treated by western medicine, many of them strongly believe in the traditional oriental Sasang constitutional classification and depend on it for food, health supplements, and oriental medicines decision making. Sasang constitutional classification is a part of traditional Korean medicine that divides people into four constitutional types (Tae-Yang: TY, Tae-Eum: TE, So-Yang: SY, and So-Eum: SE), which differ in inherited characteristics such as appearance, personality traits, susceptibility to diseases, and drug responses. It is recommended for T2DM patients to control their blood glucose very well from early stages with drugs and diet. However, many T2DM patients respond differently to their drugs, even though they receive the same medicine. Therefore, the present study investigated whether Sasang constitutional type can explain the therapeutic differences between oral hypoglycemic agents (OHAs) therapy (mono, dual and triple drug therapy). Patients of 618 with T2DM diagnosis and Sasang constitutional type known who received both western and oriental medicine treatment in a hospital between April 2006 and April 2013 retrospectively studied. HbA1c (%) and blood glucose (mg/dl) levels before OHAs therapy and 3 month after were collected for metformin (MET) or sulfonylurea (SU) monotherapy, MET+SU dual therapy, MET+except SU (where was either alpha-glucosidase inhibitor, dipeptidyl peptidase-4 inhibitor, meglitinide or thiazolidinedione) dual therapy, and triple therapy, according to Sasang constitutional type. For statistical analysis, ANOVA was used and paired t-test by SPSS 19.0 where P values less than 0.05 were considered statistically significant. Pattern was similar levels of HbA1c and blood glucose and which was decreased in order of mono, MET+SU dual, MET+except SU dual and triple therapy. In all patients comparison, for the So-yang (SY) constitutional type, either monotherapy was less effective; for Te-eum (TE) type, MET+SU dual therapy was less effective while MET+except SU dual therapy was more effective and the triple therapy was less effective; and for So-eum (SE) type, the triple therapy was more effective. For the management of TE type it is recommended to use drugs except SU when dual therapy is needed, restrict triple therapy and consider dual and insulin therapy; for SY type it is recommended to follow current guidelines; and for SE type it is advisable to skip dual therapy and start the triple therapy early. Finally, the therapeutic response to OHAs is different among Korean T2DM patients with different Sasang constitutional types. Taken together, the choice of effective OHAs therapy for each type is necessary in order to minimize the poor control of blood glucose level, the risk of complications, and the costs from a failure of therapy.

• Radiation Oncology Journal
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• 제19권3호
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• pp.224-229
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• 2001

목적 : 방사선단독으로 치료했던 자궁경부암에서 치료실패 양상과 치료실패에 대한 위험인자를 확인하여 동시항암 화학방사선요법의 적용기준을 마련하고자 본 연구를 시행하였다. 대상 및 방법 : 1989년 4월부터 1997년 12월까지 경상대학교병원 치료방사선과에서 자궁경부암으로 방사선치료를 시행받은 환자중 외부방사선조사와 강내조사를 계획대로 완료한 154명을 대상으로 후향적 분석을 시행하였다. FIGO에 의한 병기별 분포는 Ib 12명, IIa 24명, IIb 98명, IIIa 1명, IIIb 17명, IVa 2명이었다. 생존율은 Kaplan-Meyer 법을 이용하여 구하였고, 생존율의 비교는 Log-rank test로, 다변량분석은 Cox proportional hazard model을 이용하였다. 국소 또는 원격실패에 대한 단변량, 다변량분석은 logistic regression model을 사용하였다. 방광 및 직장의 합병증 평가는 RTOG/EORTC에서 제안하여 사용하고 있는 SOMA scale을 적용하였다. 결과 : 전체 154명 가운데 완전 관해를 보인 경우는 130명으로 완전관해율은 $84.4\%$였다. 완전관해자 가운데 6명이 국소재발, 25명이 원격전이, 10명이 국소재발 및 원격전이를 보여 완전관해자 가운데 $31.5\%$가 치료에 실패하였다. 연구대상 전체의 치료실패양상을 보면 국소실패가 25명, 원격실패가 25명, 국소 및 원격실패가 15명으로 전체환자의 치료실패율은 $42.1\%$ (65/154)였고, 국소실패율(국소단독실패와 국소, 원격 이중실패를 합한 것) 및 원격실패율(원격단독실패와 국소, 원격 이중실패를 합한 것)은 각각 $25.9\%$ (40/154), $25.9\%$ (40/154)였다. 국소실패의 위험인자로서는 단변량, 다변량분석 모두에서 종양의 크기가 유의하였고 원격실패의 위험인자로서는 단변량분석에서는 병리, 종양의 크기, 골반임파절전이, 치료전 혈색소 수치가 유의하였으나, 다변량분석에서는 종양의 크기, 골반임파절전이가 유의하였다. 5년 생존율은 $FIGO\;Ib\;74\%,\;IIa\;67\%,\;IIb\;63\%,\;IIb\;45\%$. 결론 : 종양의 크기가 4 cm 이상인 경우 방사선치료만으로는 국소 및 원격실패의 가능성이 높고 생존율 역시 낮다. 크기가 4 cm 이상이거나 골반임파절전이가 있는 경우 대동맥임파절 전이 가능성이 높다. 따라서 크기가 4 cm 이상이거나 골반임파절 전이가 있는 경우 국소제어율을 높이고 원격전이를 줄이기 위해 동시방사선항암화학요법을 시행하여야 한다.

• Clinics in Shoulder and Elbow
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• 제18권4호
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• pp.197-205
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• 2015

Background: The purpose of this study was to evaluate the postoperative magnetic resonance imaging (MRI) results of minimal-tying (one medial-row tie among 4 medial-row sutures) on the medial-row in double-row suture-bridge configuration ($2{\times}2$ anchor with $4{\times}4$ suture stands). Methods: From 2011 March to 2012 July, 79 patients underwent arthroscopic rotator cuff repair using $2{\times}2$ anchor double-row configuration. The mean age was 61.3 years (range, 31-81 years). Two double-loaded suture anchors were used for medial-row. Four medial-row stitches were made with only one medial-row knot-tying (the most anterior suture). Lateral-row was secured using the conventional suture-bridge anchor technique; all 4 strands were used for each anchor. Repair integrity was evaluated with MRI at mean 6.2 months postoperatively. Retear and the pattern of retear, change of fatty infiltration, and muscle atrophy of supraspinatus were evaluated using pre- and postoperative MRI. Results: Repaired tendon integrity was 38 for type I, 30 for type II, 6 for type III, 4 for type IV, and 1 for type V, according to Sugaya classification. Considering type IV/V as retear, the rate was 6.3% (5 out of 79 patients). Medial cuff failure was observed in 4 patients. Fatty atrophy of supraspinatus was significantly improved postoperatively according to Goutallier grading (p=0.01). The level of muscle atrophy of supraspinatus was not changed significantly after surgery. Conclusions: Minimal tying technique with suture configuration of four-by-four strand double-row suture-bridge yielded a lower retear rate (6.3%) in medium to large rotator cuff tears.