유한요소법을 이용한 인두의 기능이상에 대한 생체역학적 모델

김성재,배하석,최병철,김성민,Kim Sung Jae,Bae Ha Suk,Choi Byeong Cheol,Kim Sung Min 대한의용생체공학회 2003 의공학회지 Vol.24 No.6

인두는 구강과 식도, 비강과 폐의 중간에서 능동적으로 구강을 통해 섭취되는 음식물과 비강을 통해 흡입되는 공기의 통로역할을 하는 주요한 기관이다. 본 연구는 유한요소기법을 이용한 인두의 3차원 구조의 재구성 과정을 거쳐 인두의 생체역학모델을 구현하였으며, 연하곤란환자의 인두근육의 주요부분에 대한 구조적 변형특성을 3가지로 분류하여 유한요소기법을 이용하여 인두내의 압력에 대한 형상의 변형을 관찰 후 최적화 과정을 거쳐 각 부분에서의 추정 압력 구배를 측정하여 연하과정에서 내부에 생성되는 압력의 연속적인 압력분포를 추정하였다. CT에 의한 인두의 변형 형상을 추정하여 임의 압력에 의한 인두구조의 변형 형상을 유한요소 해석에 의해 계산한 후 비교하여 실제 인두강 내에 형성되는 압력을 추정하였다. 재료적 특성은 인두의 기능이상 시 근조직경화가 발생, 즉 stiffness 가 증가하는 것으로 가정하여 응력-변형률 관계에 있어서 각각 $25\%,\;50\%,\;75\%$씩 증가시켜 분석하였다. 이러한 인두의 생체역학모델은 인두기능장애를 가진 환자의 치료 계획 수립에 도움이 되는 유용한 자료를 제공 할 것으로 생각된다. Pharynx is a system transporting foods by peristaltic motion(contraction and expansion movement! into the esophagus and functioning as airway passages. In this study, structural changes of pharyngeal dysfunction are analyzed by biomechanical model using CT and FEM(finite clement method). Loading condition was assumed that equal pressure was loaded sequentially to inside of pharyngeal tissue. In order to analyze the pharyngeal muscular dysfunction by biomechanical model. the pharyngeal dysfunctions was classified into 3 cases. Taking into account the clinical complication by neuromuscular symptoms such as pharyngeal dysfunction after stroke. we assumed that a change of material property is caused by muscular tissue stiffness. A deformation of cross sectional area of the pharynx is analyzed increasing the stiffness $25\%,\;50\%,\;75\%$ in each case on the basis of stress-strain relationship. Based on three-dimensional reconstruction of pharyngeal structure using limited factor - techniques and the optimization procedure by means of inverse dynamic approach. the biomechanical model of the human pharynx is implemented. The results may be used as clinical index illustrating the degree of pharyngeal muscular dysfunction. This study may be used as useful diagnostic model in discovering early deglutitory impediment caused by physiological or pathological pharyngeal dysfunction.

잡기놀이 중심의 거친 신체놀이가 유아의 일상적 스트레스 감소에 미치는 효과

김성재(Kim Sung-Jae) 한국열린유아교육학회 2011 열린유아교육연구 Vol.16 No.1

본 연구는 잡기놀이 중심의 거친 신체놀이 활동을 구성하고, 이를 유아교육 현장에 적용하여 유아의 일상적 스트레스에 미치는 효과를 검증함으로써 유아 신체놀이의 지도방안을 제공하고자 하는 것에 목적이 있다. 전라남도 순천시에 소재한 B어린이집의 만 5세 유아 26명을 실험집단으로 10주에 걸쳐 주 2회 40분씩, 총 20회 활동을 실시한 후 t검증을 실시한 결과, 잡기놀이 중심의 거친 신체놀이 활동은 유아의 개인관련 일상적 스트레스 하위영역인 ‘자존감, 안정감, 책임감, 자아통제, 건강 ’문항과 학교관련 일상적 스트레스 하위영역인 ‘또래관계’문항, 그리고 가족관련 일상적 스트레스 하위영역인 ‘가족관계, 높은 기대수준’문항에서 일상적 스트레스 감소에 효과가 있는 것으로 나타났다. 따라서 잡기놀이 중심의 거친 신체놀이 활동은 전반적으로 유아의 일상적 스트레스 감소에 긍정적인 효과를 미친 것으로 볼 수 있다. The study was to improve mental health of preschoolers by reducing their daily stress through rough-and-tumble play based on playing tag activities. The subjects of this experiment were five-year old children, who were composed of 52 in total. The children in the experimental group participated in the rough-and-tumble play based on playing tag activity twice a week. The questionnaire designed by Parfenoff and Jose colleagues to measure young children' daily stress, which had been translated by Lee, Jung-Eun in 1992, and modified and complemented again by Song, Sung-Sook in 2001 together with 3 other early childhood education experts, was used for this study. In order to measure the effect of program applied in the study, t-verification for independent samples was executed, and for statistical process, SPSS16.0 for Window was used. The rough-and-tumble play based on playing tag activities was found to reduce the preschoolers' daily stress.

경남 시군별 자연재해 취약성 평가 및 유형 분류

김성재,김용완,최영완,김성민,장민원,Kim, Sung Jae,Kim, Yong Wan,Choi, Young Wan,Kim, Sung Min,Jang, Min Won 한국관개배수위원회 2012 한국관개배수논문집 Vol.19 No.1

This study aimed to evaluate the vulnerability to different natural hazards such as flood, drought, and abnormal climate, and to classify the vulnerability patterns in Gyeongsangnam-do. The damage records and annual budgets during 2000 to 2009 were collected and were ranked for all twelve si-guns. Sancheong-gun and Hamyang-gun resulted in the most vulnerable to flood and drought damages, and Hadong-gun and Yangsan-si were most damaged from abnormal climate such as heavy snow and heavy wind. In addition, three clusters were classified by using Ward's method, and were interpreted. The results showed that the western areas of Gyeongsangnam-do might be more vulnerable to flood damage while drought might threaten the eastern si-guns.

논문 - 기후변화에 따른 농업생산기반 재해 취약성 평가를 위한 대리변수 선정

김성재,박태양,김성민,김상민,Kim, Sung-Jae,Park, Tae-Yang,Kim, Sung-Min,Kim, Sang-Min 한국관개배수위원회 2011 한국관개배수논문집 Vol.18 No.2

Climate change has impacts on not only the average temperature rise but also the intensity and frequency of extreme events such as flood and drought. It is also expected that the damages on agricultural infrastructure will be increased resulting from increased rainfall intensity and frequency caused by climate change. To strengthen the climate change adaptation capacity, it is necessary to identify the vulnerability of a given society's physical infrastructures and to develop appropriate adaptation strategies with infrastructure management because generally facilities related to human settlements are vulnerable to climate changes and establishing an adaptive public infrastructure would reduce the damages and the repair cost. Therefore, development of mitigation strategies for agricultural infrastructure against climatic hazard is very important, but there are few studies on agricultural infrastructure vulnerability assessment and adaptation strategies. The concept of vulnerability, however, is difficult to functionally define due to the fact that vulnerability itself includes many aspects (biological, socioeconomic, etc.) in various sectors. As such, much research on vulnerability has used indicators which are useful for standardization and aggregation. In this study, for the vulnerability assessment for agricultural infrastructure, 3 categories of climate exposure, sensitivity, and adaptation capacity were defined which are composed of 16 sub-categories and 49 proxy variables. Database for each proxy variables was established based on local administrative province. Future studies are required to define the weighting factor and standardization method to calculate the vulnerability indicator for agricultural infrastructure against climate change.

일절개법을 이용한 관절경적 후 십자 인대 복원술 - 이절개법과의 비교 -

김성재,김현곤,김현정,김한식,Kim, Sung-Jae,Kim, Hyun-Kon,Kim, Hyon-Jeong,Kim, Han-Sik 대한관절경학회 1998 대한관절경학회지 Vol.2 No.1

This study was done to compare the results of the one-incision technique and the conventional two incision technique for the arthroscopic treatment of the posterior cruciate ligament injury. Fifty-five patients with the posterior cruciate ligament injury underwent the arthroscopic posterior cruciate ligament reconstruction using bone-patellar tendon-bone(BTB) graft. Patients with combined ligament injuries requiring concomitant operative treatment were excluded in this study. The conventional two-incision technique was performed in ten patients(Group I) and the one-incision technique in forty-five patients(Group II). The average duration of follow-up was 45 months in Group I(range, 40 to 50 months) and 36 months in Group II(range, 24 to 68 months). Auto BTB grafts were utilized for all patients in Group I. In Group II, 34 BTB autografts and 11 BTB allografts were utilized. The functional results were evaluated according to the Lysholm Knee Scoring scale and the Hospital for Special Surgery(HSS) knee ligament rating form. The postoperative posterior laxity was measured with a KT 1000 or 2000 arthrometer. Lysholm postoperative mean values were 90.0 in Group I and 90.6 in Group II. HSS mean values were 87.7 in Group I and 92.6 in Group II. HSS postoperative mean value showed better results in Group II(p=0.037). The average side-to-side difference of the posterior translation measured by the KT 2000 arthrometer were 2.10 mm(range, 1 to 4 mm) in Group I and 2.38 mm(range, 0 to 5 mm) in Group II. But there was no statistically significant difference. In Group II, the results of the autograft and allograft showed no significant difference. The arthroscopic posterior cruciate ligament reconstruction using one-incision technique showed good results comparable to the conventional two-incision technique. This technique minimizes potential injury to the extensor mechanism, especially vastus medialis obliquus, and scar formation over the medial femoral condyle. The operation can be finished within one tourniquet time by using only one-incision.

수술후 발생한 슬관절 강직의 관절경적 유리술

김성재,신상진,이원용,김진용,김상곤,Kim Sung-Jae,Shin Sang-Jin,Lee Won-Yong,Kim Jin-Yong,Kim Sang-Gon 대한관절경학회 2000 대한관절경학회지 Vol.4 No.1

목적 : 수술후 발생한 슬관절 강직 환자에 있어서 관절경적 슬관절 유리술의 결과와 결과에 영향을 미치는 예후 인자에 대하여 살펴 보고자 하였다. 대상 및 방법 : 본 논문은 슬관절 주위 골절 및 인대 수술후 발생한 슬관절 강직 환자중 관절경적 슬관절 유리술을 시행받은 31례의 환자를 대상으로 하였다. 관절경적 슬관절 유리술은 3개월 이상의 적극적인 물리 치료에도 불구하고 술후 슬관절 운동 범위에 호전이 없거나 기능 제한이 있었던 경우에 시행하였다. 관절 강직의 선행 요인으로 인대 수술이 17례로 가장 많았으며 슬관절 주위의 관절면을 침범한 골절이 10례였고 그 밖의 경우가 4례였다. 결과 : 술전 관절 운동 범위가 평균 60도(14도-74도)에서 수술 직후 평균 120도(7도-127도)였으며 최종 추시 관찰시 129도(3도-132도)였다. 인대 수술후 관절 강직이 유발된 17례의 환자에서는 술전 65도에서 술후 135도로 향상되었고 이는 술후 약 1년간에 걸쳐 서서히 증가되었다. 관절내 골절후 관절 강직이 유발된 군에서는 술전 60도에서 술후 125도로 증가하였고 이는 술후 6개월에 걸쳐 운동 범위가 증가하였다. 또한 이환기간이 7개월 이내인 환자군에서는 관절경적 슬관절 유리술 시행후 관절 운동 범위가 평균 70도 증가하였고 7개월 이상인 군에서는 술후 평균 49도 증가하였다. 결론 : 관절경적 슬관절 유리술은 슬관절 내에서 기인된 관절 강직의 치료에 효과적이며 특히 인대 수술후에 유발된 관절 강직이나 증상이 7개월 이내의 관절 강직에서 보다 향상된 결과를 보였다. We retrospectively reviewed the results of arthroscopic adhesiolysis on postoperative knee stiffness in order to observe the clinical improvement and to evaluate the prognostic factors. Arthroscopic adhesiolysis without extraarticular procedure was performed in 31 knees displaying persistent flexion or extension loss. The causes of arthrofobrosis were previous ligament surgeries in 17 knees, surgery for a fracture involving the articular surface of the knee in 10 cases and other causes in four cases. The average range of motion was $60^{\circ}(range,\;14^{\circ}-74^{\circ})$ preoperatively, and improved by $120^{\circ}(range,\;7^{\circ}-127^{\circ})$ immediately following the procedure. The range of motion at the final follow-up (average 34 months) was $129^{\circ}(range,\;3^{\circ}-132^{\circ})$. In the 17 patients with arthrofibrosis fellowing ligament surgery, the range of motion was improved from $65^{\circ}$ preoperatively to $135^{\circ}$ at final follow-up. The improvement in function and motion was achieved during the first postoperative year. In the 10 patients with arthrofibosis following intraarticular fractures, the range of motion was improved from $60^{\circ}$ preoperatively to $125^{\circ}$ at the final follow-up, and most of the increase in motion was achieved within the first 6 months. Patients who suffered from a limitation of motion for less than 7 months gained an average $70^{\circ}$ improvement in total range of motion following arthroscopic surgery. However, the total range of motion in patients with a duration of symptoms greater than 7 months improved by an average $49^{\circ}$ postoperatively. In conclusion, arthroscopic adhesiolysis without incisional procedure is an effective therapeutic modality in arthrofibrosis of intraarticular origin. Improved outcomes can be expected in stiffness after ligament surgery and a symptom duration of arthrofibrosis less than 7 months.

실트펜스와 식생밭두렁 적용을 통한 밭 비점오염 저감효과 분석을 위한 포장실험 연구

김성재,박태양,김성민,장정렬,김상민,Kim, Sung-Jae,Park, Tae-Yang,Kim, Sung-Min,Jang, Jeong-Ryeol,Kim, Sang-Min 한국농공학회 2012 한국농공학회논문집 Vol.54 No.4

The objective of this study was to test the pollutant reduction effect by the silt fence and vegetated ridge through field monitoring. The experiment plots were established with two replication and three treatments. Each plot was designed with 5 m width, 22 m length, and 3 % slope. Flumes with the floating type stage gages were installed at the outlet of each plot to monitor the runoff. For a rainfall monitoring, tipping bucket rain gage was installed within the experiment site. Cultivated crops were spring daikon and autumn chinese cabbage. Analysis of variance (ANOVA) indicated that the water quality concentration from three experiment plots were not significantly different in 5 % of significant level. The monitoring results showed that the average pollution loads reduced by silt fence compared to control were SS 75.33 %, TN 40.87 %, TP 56.58 %, BOD 52.12 %, COD 36.07 %, TOC 34.99 %; by vegetated ridge compard to control were SS 65.27 %, TN 81.80 %, TP 54.26 %, BOD 67.09 %, COD 46.55 %, TOC 43.30 %. Analysis of Spearman's rank correlation coefficient showed that BOD-SS and SS-Turbidity were highly related at the silt fence and vegetated ridge plots. In all plots, SS-Turbidity and TP-TN relations were relatively high. The monitoring results showed that the silt fence and vegetated ridge were effect method to reduce the pollutant loads from the field runoff. Long-term monitoring is required to obtain more quantitative reduction effect for diverse crops and to increase the reliability of results.

프리캐스트 PSC 곡선 거더교의 구조거동에 대한 실험적 연구

김성재,김성배,엄기하,김장호,Kim, Sung Jae,Kim, Sung Bae,Uhm, Ki Ha,Kim, Jang Ho Jay 대한토목학회 2014 대한토목학회논문집 Vol.34 No.6

교통수요의 증가에 따른 교통혼잡을 피하기 위하여 고가도로와 고속도로, 경전철 등이 활발히 건설되고 있으며, 이에 따라 접속부 등과 같은 곡률반경이 작은 곡선교 구간의 발생이 증가하고 있다. 초기에는 직선형의 주형을 연결하여 곡선을 이루는 방법을 사용하였으나, 공사비의 증가와 미관성 측면에서 용이하지 않아 강재를 사용한 곡선주형이 개발되어 적용되고 있다. 강재의 특성상 기하학적인 형상을 구현하는데 상대적으로 손쉽기 때문에 대부분의 곡선교에서는 강재를 이용한 강박스 거더교를 주로 사용하고 있다. 그러나 강박스 거더교는 초기 공사비가 고가이고, 도장과 같은 지속적인 유지관리가 필요한 문제점을 가지고 있다. 최근에는 I형 강재 플레이트 거더를 사용하는 방법이 활발히 연구되고 있으나 곡선 I형상의 특성상 개단면이고 얇은 플레이트를 사용하기 때문에 비틀림 강성이 매우 작아 안전성에 문제가 있는 것으로 지적되고 있다. 이러한 곡선강교의 대안으로 경제성과 안전성이 확보되는 프리캐스트 PSC 곡선거더가 제시되고 있다. 이에 본 연구에서는 프리캐스트 PSC 곡선거더를 효율적으로 제작할 수 있는 스마트 몰드 시스템을 개발하고 이를 적용한 2주형 40m 실물교량의 정적 휨 파괴 실험을 통하여 안전성을 확인하고자 한다. 제작단계에서 단일 거더는 곡률반경에 의해 거더의 전도에 대한 안정성이 문제가 있으나 가로보로 연결된 멀티거더는 하중분배가 적절히 이루어지며 안정성이 확보되는 것으로 나타났다. 정적구조 실험결과에서는 균열하중(1,400 kN)이 설계하중(450 kN)의 약 3배 이상 높은 것으로 나타났으며, 허용처짐량에 해당하는 하중은 설계하중의 4배인 1,800 kN에서 발생하여 사용성과 안전성이 모두 확보되는 것으로 나타났다. Recently, many overpasses, highway, and advanced transit systems have been constructed to distribute the traffic congestion, thus small size of curved bridges with small curvature such as ramp structures have been increasing. Many of early curved bridges had been constructed by using straight beams with curved slabs, but curved steel beams have replaced them due to the cost, aesthetic and the advantage in building the section form and manipulating the curvature of beams, thereby large portion of curved bridges were applied with steel box girders. However, steel box girder bridges needs comparatively high initial costs and continuous maintenance such as repainting, which is the one of the reason for increasing the cost. Moreover, I-type steel plate girder which is being studied by many researchers recently, seem to have problems in stability due to the low torsional stiffness, resulting from the section characteristics with thin plate used for web and open section forms. Therefore, in recent studies, researchers have proposed curved precast PSC girders with low cost and could secured safety which could replace the curved steel girder type bridges. Hence, this study developed a Smart Mold system to manufacture efficient curved precast PSC girders. And by using this mold system a 40 m 2-girder bridge was constructed for a static flexural test, to evaluate the safety and performance under ultimate load. At the manufacturing stage, each single girder showed problems in the stability due to the torsional moment, but after the girders were connected by cross beams and decks, the bridge successfully distributed the stress, thereby the stability was confirmed. The static loading test results show that the initial crack was observed at 1,400 kN when the design load was 450 kN, and the load at the allowable deflection by code was 1,800 kN, which shows that the safety and usability of the curved precast PSC bridge manufactured by Smart Mold system is secured.

주성분 분석을 이용한 농업생산기반의 재해 취약성 평가에 관한 연구

김성재,김성민,김상민,Kim, Sung Jae,Kim, Sung Min,Kim, Sang Min 한국농공학회 2013 한국농공학회논문집 Vol.55 No.1

The purpose of this study was to evaluate climate change vulnerability over the agricultural infrastructure in terms of flood and drought using principal component analysis. Vulnerability was assessed using vulnerability resilience index (VRI) which combines climate exposure, sensitivity, and adaptive capacity. Ten flood proxy variables and six drought proxy variables for the vulnerability assessment were selected by opinions of researchers and experts. The statistical data on 16 proxy variables for the local governments (Si, Do) were collected. To identify major variables and to explain the trend in whole data set, principal component analysis (PCA) was conducted. The result of PCA showed that the first 3 principal components explained approximately 83 % and 89 % of the total variance for the flood and drought, respectively. VRI assessment for the local governments based on the PCA results indicated that provinces where having the relatively large cultivation areas were categorized as vulnerable to climate change.

한국의 의과대학생에서 기분과 행동의 계절적 변동

김성재,이헌정,최현석,정현강,김봉주,김주연,이영우,조동혁,이민수,조숙행,김린,Kim, Sung-Jae,Lee, Heon-Jeong,Choi, Hyun-Seok,Jung, Hyun-Gang,Kim, Bong-Ju,Kim, Ju-Yeon,Lee, Young-Woo,Cho, Dong-Hyuk,Lee, Min-Soo,Joe, Sook-Haeng,Kim, Leen 대한수면의학회 2004 수면·정신생리 Vol.11 No.2

목 적:계절성 정동장애에 대한 연구는 북미, 유럽과 아시아의 일본과 중국 등 여러 국가에서 시행되었지만, 한국에서는 아직 보고된 적이 없다. 이 연구는 한국의 의과대학생에서 기분과 행동의 계절적 변동의 빈도를 평가하기 위하여 시행되었다. 방 법:서울의 고려대학교 의과대학에 재학중인 학생 중 총 297명을 대상으로 하였다. 계절성을 평가하기 위하여 계절성 양상 평가 설문지(SPAQ)의 한국어 번역판을 이용하였고, 계절성 정동장애(SAD)와 아임상성 계절성 정동장애(S-SAD)를 진단하기 위하여 Kasper가 제시한 진단기준을 이용하였다. 결 과:전반적 계절성 점수(GSS)의 평균은 6.6(SD=3.9)이었다. 83.5%(N=248)가 계절성 변화가 생활에 영향을 미친다고 보고하였고, 단지 3.7%(N=11)만이 계절성 변화가 전혀 없다고 보고하였다. 전체 SAD의 유병률은 15.2%, SSAD의 유병률은 11.1%로 나타났다. 이중 여름철 SAD는 3.0%, 여름철 S-SAD는 2.7%였으며, 겨울철 SAD는 11.4%, 겨울철 S-SAD는 5.8%로 겨울철 SAD 및 S-SAD가 더 높은 유병률을 나타내었다. 결 론:이 결과를 통해 한국인에서 기분과 행동에 있어서 계절적 변동은 흔한 것임을 알 수 있다. 여름철보다 겨울철의 SAD와 S-SAD가 더 높은 유병률을 보이는 것은 미국 등에서 보고된 결과와는 일치하지만 일본, 중국과 같은 다른 아시아 국가의 보고와는 반대되는 것이다. Objectives: Although many studies on seasonal variations in mood and behavior have been carried out in foreign countries, no such study has previously been undertaken in Korea. The goal of this study was to estimate the frequency of seasonal variations in mood and behavior among Korean medical students. Methods: 297 medical students from Korea University College of Medicine participated in this study. The subjects were surveyed with a Korean translation of the Seasonal Pattern Assessment Questionnaire (SPAQ), and their responses were evaluated for seasonal patterns of mood and behavioral change, including seasonal affective disorder (SAD) and subsyndromal seasonal affective disorder (S-SAD), derived from the case-finding criteria of Kasper et al. Results: The mean global seasonality score was 6.6 (SD=3.6). 83.5% (N=248) of the subjects reported some changes in behavior and mood associated with the seasons. Only 3.7% (N=11) reported no behavioral changes across the seasons. Total prevalence rates were 15.2% for SAD, and 2.7% for S-SAD. The estimated frequencies were 3.0% for summer SAD, 2.7% for summer S-SAD, 11.4% for winter SAD, and 5.8% for winter S-SAD. The prevalence rates for winter SAD or S-SAD were higher than the prevalence rates for summer SAD or S-SAD. Conclusion: These results suggest that seasonal variations in mood and behavior are common among Koreans. The higher prevalence rate of winter SAD or S-SAD than summer SAD or S-SAD is consistent with most western studies and stands in contrasts to studies in other Asian countries, such as Japan and China.