개선된 전력 시스템 주파수 추정 알고리즘

김철훈(Cheol-Hoon Kim),강상희(Sang-Hee Kang) 대한전기학회 2009 대한전기학회 학술대회 논문집 Vol.2009 No.11

전력 시스템 주파수를 추정하기 위해 일반적으로 사용되고 있는 직교변환법을 이용한 알고리즘을 개선하였다. 주파수 변동 시 피드백 루프를 이용하여 변동된 주파수 기반으로 직교변환을 함으로써 알고리즘의 정확도를 개선하였다. 개선된 알고리즘은 고장상태에서 주파수 추정 시 신뢰도 향상에 기여할 것으로 기대된다.

Bluetooth Beacon을 활용한 D2D 단말 탐색 기법

김철훈(Kim Cheol Hoon),이성원(Lee Sung Won),정성호(Seong-Ho Jeong) 한국통신학회 2015 한국통신학회 학술대회논문집 Vol.2015 No.06

이종의 Beacon 신호 송수신을 통한 iBeacon의 성능 개선에 관한 연구

김철훈(Cheol-hoon Kim),홍승현(Seung-hyun Hong),이성원(Sung-won Lee) 한국통신학회 2015 韓國通信學會論文誌 Vol.40 No.1

측두하악장애환자에서 악관절 세척술후 관절활액의 전구염증성 Cytokines의 발현

김철훈(Cheol-Hun Kim),황희성(Hie-Sung Hwang),신상훈(Sang-Hoon Shin),정인교(In-Kyo Chung),황태호(Tae-Ho Hwang) 대한구강악안면외과학회 2005 대한구강악안면외과학회지 Vol.31 No.5

The purpose of this study is that evaluate the distribution and biological roles of TNF-a, interleukin-1β(IL-1β), interleukin-6(IL-6) and tissue inhibitors of metalloproteinase-1(TIMP-1) in the synovial fliud of patients with non-inflammatory chronic temporomandibular joint(TMJ) disorders in relation to pain during joint movements and magnetic resonance imaging(MRI) findings. TMJ synovial fluids aspirates were obtained from 36 patients (36 joints) with chronic TMJ disorders and from 8 controls(8 joints). Patients were divided to four groups. The control group was from healthy volunteers(8 joints), group I(18 joints) was patients with anterior disc displacement with reduction, group II(5 joints) was patients with disc displacement without reduction and group III (5 joints) was osteoarthritis. The TNF-α, IL-1βand IL-6 levels in the aspirates were determined by using an enzyme-linked immunosorbent assay and the TIMP-1 level was measured by an enzyme immunoassay. Following examinations for pain during joint movements and MRI observations, these cytokines’level and frequencies of detection were compared. The level of IL-1βwas not significant different in all groups. but the level of TNF-α, IL-6 and TIMP-1 were significant different among groups. The level of IL-6 and TIMP-1 were correlated to pain during movement(p〈0.01) and the level of TNF-a(p〈0.05). Also, the level of IL-6 was correlated to the level of TIMP-1(p〈0.01). Especially, The level of the TIMP-1 level was significantly correlated to the pain during movement and showed very high levle of Pearson’s correlation coefficient (r=0.833)(p〈0.001). The results indicated that the TNF-α, IL-6 and TIMP-1 levels in the TMJ aspirates of patients with chronic TMJ disorders have been raised. Especially, IL-6 and TIMP-1 were very high levels in the patients who were degraded in the TMJ. Also, TNF-α, IL-6 and TIMP-1 showed the significant correlation in the chronic temporomandibular joint disorders. Therefore I suggest that these cytokines were also correlated to the pain during movement in the chronic temporomandibular joint disorders

백서 하악골에서 신연골형성술시 압축력의 효능에 관한 실험적 연구

강항립(Hang-Rip Kang),김철훈(Cheol-Hun Kim),신상훈(Sang-Hoon Shin),정인교(In-Kyo Chung),김욱규(Uk-Kyu Kim) 대한구강악안면외과학회 2004 대한구강악안면외과학회지 Vol.30 No.5

Distraction osteogenesis is a biologic process of new bone formation between the surfaces of bone segments that are gradually separated by incremental traction. Distraction osteogenesis is clinically applied as a new treatment modality of mandibular hypoplasia or bony defect area in maxillofacial area by many studies of distraction devices and method. But disadvantage of distraction osteogenesis shows unfavorably long consolidation period and relapse tendency. Therefore. this experiment was designed to investigate the effectiveness of combined application of distraction and compression force for improving of bone quality and shortening of treatment period during distraction osteogenesis. Twenty-one Sprague-Dawley rats with 300~350gm were used. These were divided into two group as distraction group and combination group was applied with compression force in the consolidation period. The rat were sacrificed for gross finding, radiographic and histologic findings. at 2, 4 weeks after distraction. The result were follow : 1. On radiographic finding, all experimental groups appeared more radiopacity than control groups both at 2, 4 weeks after distraction. 2. On histologic finding, trabeculae of bone and mature lamellar bone were showed increasingly in experimental group. Ossification occured rapidly. From this study, we may suggest that compression force application in consolidation period during distraction osteogenesis can be useful method improve bone quality and to shorten the treatment period. But more experimental and clinical studis are necessitated on effects of compression force application during distraction osteogenesis.

인공지능 기반 블랙아이스 예측 및 대응 시스템

서민재(Min-Jae Seo),김시광(Si-Gwang Kim),김철훈(Cheol-Hoon Kim),변지훈(Ji-Hun Byun),백동현(Dong-Hyun Baek),허준혁(Jun-Hyeok Heo),박성원(Sung-Won Park) 대한전기학회 2023 대한전기학회 학술대회 논문집 Vol.2023 No.11

하악골 신장술에서 압축자극을 통한 골재생시 TGF-β1, Osteonectin 및 BMP-4의 발현

박성진(Seong-Jin Park),김욱규(Uk-Kyu Kim),정인교(In-Kyo Chung),황대석(Dae-Seok Hwang),김용덕(Yong-Deok Kim),신상훈(Sang-Hun Shin),김철훈(Cheol-Hoon Kim),변준호(June-Ho Byun) 대한구강악안면외과학회 2007 대한구강악안면외과학회지 Vol.33 No.4

Distraction osteogenesis(DO) is a technique of lengthning bone including soft tissue by gradual separation of surgically divided bone surfaces. Distraction osteogenesis combination with a compression stimulation(DO-CO) was a new technique by authors to enhance new bone quality and to shorten the consolidation period. The purpose of this study was to compare DO with DO combined with compression force in efficiency by evaluating the expression of TGF-β1, osteonectin and BMP-4 on bone regenerate in rabbit mandible. Fourty two rabbits were used for this experiment. On the control group, the distraction was carried out at the rate of 1 ㎜ per day to obtain the amount of 8 ㎜ distraction for 8 days. On the experimental group, the distraction was carried out at the rate of 1㎜ per day for 10 days, 3 days-latency period, and then the compression was carried out as counter direction 1 ㎜ per day for 2 days. After 0 day, 5 days, 13 days, 20 days, 27 days, 34 days and 41 days, three rabbits on each group were sacrificed and the distracted portion of mandible were cut and treated for RT-PCR observation. The level of expression of TGF-β1 and osteonectin were shown more and longer expression in the experimental group than in the control group. The expression of BMP-4 was maintained with high level during the entire experimental period in both groups. These findings suggested that DO with compression stimulation could be a favorable technique for obtaining a good new bone quality.

유치 치근단 염증에 의한 계승치 맹출장애의 일예

김철훈,임두영,황인성,손홍규,최돈옥 大韓小兒齒科學會 1982 大韓小兒齒科學會誌 Vol.9 No.1

This is a case report of difficult eruption of succeeding permanent tooth by periapical inflammation of primary tooth. 12-year-8-month-old girl who had been treated by pulpotomy of lower right second primary molar about 4 years ago was recalled for prolonged retention of it. Radiographs showed periapical inflammation of lower right second primary molar and horizontal buccal impaction of succeeding permanent tooth. Right second premolar seemed impossible to erupt so surgical extraction of it was done with removal of lower right second primary molar and resin space maintainer was manipulated for prevention of space closure and elongation of opposing tooth.

건강검진 수진자에서의 대사증후군 관련 생활습관

김철훈,유병철,이용환 KOSIN UNIVERSITY COLLEGE OF MEDICINE 2006 高神大學校 醫學部 論文集 Vol.21 No.1

Background: Metabolic syndrome is caused by interplay between genetic and many environmental factors. Some behaviors or lifestyle patterns including physical activity, cigarette smoking, and diet, particularly carbohydrate and fat intake are associated with the metabolic syndrome. The objective of this study was to identify the relationship between metabolic syndrome and some lifesyle behaviors. Methods: A total of 635 medical check-up examinees who were examined in Kosin University Gospel Hospital from December, 2004 to July, 2005 were enrolled in this study. The height, weight, waist circumference, and systolic and diastolic blood pressure of the subjects were examined and on concentrations of fasting blood glucose, total cholesterol, HDL cholesterol, LDL cholesterol, and triglyceride in peripheral venous blood were measured. The metabolic syndrome was defined as the presence of three or more of the following; waist circumference men ≥90 cm, women ≥80 cm, blood pressure ≥130/85 mmHg, fasting glucose ≥110 mg/dL, HDL cholesterol, men <40 mg/dL, women <50 mg/dL, and triglyceride ≥150 mg/dL. The blood pessure, fasting glucose, HDL cholesterol, triglyceride were evaluated by using the criteria of NECP ATP Ⅲ and waist circumference was assessed by using the criteria of WHO Asia-Western Pacific. Self-administered questionnare was conducted on smoking, alcohol drinking, educational level, exercise, and dietary practices. Results: The prevalence of the metabolic syndrome was 37.5%. High fat intake was significantly associated with an increased risk of having the metabolic syndrome. In women, low educational level and high carbohydrate intake were associated with an increased risk of having the metabolic syndrome. High fat intake was significantly associated with an increased risk of having the metabolic syndrome in body mass index ≥25/0 kg/m2 or 50-59 years group. Conclusion: Low educational level, high fat and high carbohydrate intake were significantly associated with an increased risk of having the metabolic syndrome.

유견 영구치의 근단형성에 관한 실험적 연구

김철훈 大韓小兒齒科學會 1993 大韓小兒齒科學會誌 Vol.20 No.1

The purpose of this study is to investigate the differences of root formation by using different three materials histopathologically. 11 beagle dogs about 6 months old and 11.2kg by mean weight were used for root canal filling, a total of 94 root canals from 54 mandibular premolars with immature roots. Pulp tissues were exprirpated and root canals were left open for 2 weeks before debridement,and filled with Ca(OH)2-CMCP paste for control group and Vitapex, A.R.S.(Apatite Root Sealer type Ⅱ) for experimental groups. The teeth were then observed for the healing of periapical tissues, types of apical closure and hard tissue formation at 30,90,180 days after the treatment histopathologically. The results were as follows: 1.In final evaluation, it revealed 70% as good, 20% as fair and 10% as poor in control group, 74% as good, 20% as fair and 6% as poor in Vitapex group, and 36% as good, 45% as fair and 19% as poor in A. R. S. group. 2.In the status of apical closure, 80% of the control group, 91% of the Vitapex group and 73% of the A. R. S. group were observed for complete and incomplete apical closure. 3.Of the 5 types of apical closure, closure at apcial foramen type was most common(mean 52%) in all groups. And extracanal closure types were more common in control group compaired with experimental groups. Root growth types were not observed. 4.In X-ray evaluations, proper canal filling cases were more evaluated as good and fair,and poor cases were not observed in experimental groups. In the treatment of immature permanent teeth with infected root canals, Vitapex produced better results than Ca(OH)2-CMCP paste. Cases evaluated as poor for A. R. S. were more common and so more longer period observation is needed.