• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.92-96
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• 2015

Due to unique characteristics of small construction companies, safety management is comprised of complex problems (e.g., resources constraints, a lack of formalized management structures, low level of management safety commitment etc.). In order to understand causal interdependencies between safety factors at different system levels (regulation, organization, technical and individual), this paper aims to develop a system dynamics (SD) model of safety management in small construction companies. The purpose of the SD model is to better understand why small construction companies have low level of safety performance. A causal loop diagram (CLD) was developed based on literature, with an attempt to map causal relationships between variables. The CLD was then converted into stock and flow diagram for simulation. Various tests were conducted to build confidence in the model's ability to represent the reality. A number of policies were analyzed by changing the value of parameters. The value of a system dynamics approach to safety management in small construction companies is its ability to address joint effects of multiple safety risk factors on safety performance with a systems thinking perspective. By taking into account feedback loops and non-linear relationships, such a system dynamics model provides insights into the complex causes of relatively poor safety performance of small construction companies and improvement strategies.

• 한국임상약학회지
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• 제22권4호
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• pp.330-339
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• 2012

Background : Hypertension is treated with both lifestyle modification and pharmacotherapy. The Seventh Report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure (JNC-7), published in 2003, provides a streamlined management approach to hypertension for the primary care physician. The JNC-7 is the gold standard also in Korea. According to the JNC-7, special therapeutic considerations are recommended for high-risk individuals with compelling indications. The presence of compelling indications in any given patient should be considered when selecting specific pharmacotherapy to treat hypertension. However, in patients with compelling indications, it is unknown that hepatotoxicity is caused by Calcium Channel Blocker (CCB), one of 1st anti-hypertensive drugs. Now, the CCB is the most used 1st anti-hypertensive drug in Korea Therefore, we evaluated the changes in blood liver function parameters (ALT, AST, Total bilirubin, serum albumin) for the study group. Methods : We randomly collected and retrospectively analyzed Electronic Medical Record data (n=28,788) of patients, and who took calcium channel blockers(non-dihydropyridines; diltiazem, verapamil, dihydropyridines; amlodipine, barnidipine, benidipine, clinidipine, efonidipine, felodipine, isradipine, lacidipine, lercanidipine, nicardipine, nifedipine, nimodipine), with having liver function tests (LFTs) from July 1st 2009 to June 30th 2010 at the Seoul National University Hospital in Korea. Control groups are two antihypertensive agents: RAS blockade (ARB; candesartan, irbesartan, losartan, olmesartan, telmisartan, valsartan, ACE-I; cilazapril, enalapril, fosinopril, imidapril, perindopril, ramipril) and, Diuretics (loop; furosemide, torsemide, thiazide; hydrochlorothiazide[HCTZ], indapamide). Patients not having LFT results at these three standard points of time(baseline, during, medication, and after finishing medication) were excluded. The collected data were analyzed by using the SPSS (Version12.0) and Microsoft Excel (Version2007). Results : 711 patients who were treated CCB (297), RAS blockade (232) or Diuretics (182) monotherapy were selected for the study. In selected patients, liver damage degree(changes of each LFTs value) was higher in diuretics group than other groups, followed by RAS blockade and CCB. In diuretics group's was loop-diuretics group was higher than thiazide-diuretics group. In CCB group, Nondihydropyridine-CCB's damage degree was higher than Dihydropyrine-CCB's that. Conclusions : Despite the limitations due to the retrospective study, among patients with abnormal LFTs, the use of CCBs led to a less liver damage than other 1st anti-hypertensive agents. It can be recommended CCBs as one of the initial treatments of hypertension in patients with liver disease.

• 한국식품영양과학회지
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• 제32권3호
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• pp.437-443
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• 2003

선행연구에서 라이코펜이 HT-29세포의 증식을 억제하는 것을 관찰하였기 때문에 본 연구는 그 기전을 연구하기 위하여 수행되 었다. 라이코펜이 HT-29 세포의 사멸을 유도하는지 조사하기 위해서 여러 농도의 라이코펜이 포함된 배지에서 세포를 4일 동안 배양하였다. 라이코펜 농도의 증가에 따라 사멸되는 세포에서 나타나는 특징의 하나인 DNA fragmentation이 증가하는 것을 관찰하였다. Western blot을 수행하여 얻은 결과에 의하면 라이코펜이 IGF-IR, IRS-1, PI3K, Akt와 같은 IGF-IR pathway에 속하는 단백질의 수준을 감소시켰다. IGF-IR의 인산화를 유도하기 위해서 라이코펜이 포함된 배지에서 세포를 배양하고 IGF-I을 첨가하여 0, 5, 10, 60분간 배양한 다음 IGF-IR antibody를 이용하여 immunoprecipitation을 수행하였다. 라이코펜은 IGF-I에 의한 IGF-IR, IRS-1의 인산화와 IGF-IR와 PI3K의 결합을 감소하고 인산화된 Akt를 감소시켰다. 이와 같은 IGF-IR signaling의 억제는 이 대장암세포에 존재하는 IGF-II의 autocrine loop을 억제하는 원인이 될 수 있어, 라이코펜의 암세포증식을 억제하는 기전 중의 하나가 될 수 있다. 라이코펜은 토마토와 그 가공품에 많이 존재하는 물질로 자연적인 식사를 통해 많이 섭취할 수 있는 물질이다. 라이코펜의 항암 기전을 밝혀냄으로써 미래 암예방과 치료를 위한 중요한 기능성 영양소를 생산할 수 있는 기초를 마련해줄 수 있을 것으로 기대된다.

• 방송공학회논문지
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• 제20권5호
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• pp.687-696
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• 2015

최근 동영상 압축에 관한 국제 표준화 기구인 JCT-VC (Joint Collaborative Team on Video Coding) 에서는 High Efficiency Video Coding (HEVC)의 확장 표준으로 HEVC/Range Extension (HEVC/RExt)의 개발을 완료하고 스크린 콘텐츠 동영상의 부호화기술을 위한 표준인 HEVC/Screen Content Coding (HEVC/SCC)을 제정 중이다. 기존 동영상 압축 과정에서는 이미지 센서로부터 취득한 RGB 영상을 변환하여 부호화를 수행하는 반면에 애니매이션, 그래픽스 등 컴퓨터로 합성한 영상을 일컫는 스크린 콘텐츠의 경우는 색 공간의 변환이 주관적 화질을 심각하게 열화 시킬 수 있으므로 기존 RGB 색 공간을 유지하며 효율적으로 색 공간 내 정보의 중복성을 줄이기 위한 부호화 기법이 필요하다. 본 논문에서는 HEVC/RExt.와 HEVC/SCC에서 개발한 스크린 콘텐츠 동영상 압축을 위한 색 요소 예측 기법과 루프 내 색 공간 변환 기술의 성능을 분석한다. 실험 결과에 의하면 색 요소 예측 기법은 평균 약 11.7% BD-rate 감소, 색 공간 예측 기법은 평균 약 16.4% BD-rate 감소를 보인다. 그러나 두 기법이 동시에 적용되는 경우 약 18.2%의 BD-rate 감소를 보여 두 기법의 부호화 효율이 약 9.9% 중첩된다. 본 결과를 응용하여 두 기법이 배타적으로 선택이 되게끔 부호기 고속화를 수행하는 경우 약 0.3%의 부호화 손실로 93%의 부호화 측정 시간을 제공한다.

• 한국전자파학회논문지
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• 제18권4호
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• pp.448-454
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• 2007

본 논문에서는 CR(Cognitive Radio)의 가장 적합한 인공지능 기술로 주목받고 있는 게임 이론을 전력 제어 방식에 적용해 CDMA 시스템 기반의 사용효율과 효용에 대한 성능 평가 결과를 제시하였다. 사용자와 네트워크 동시 최적화를 위한 효용함수식을 정의하였으며 모의실험을 통해 FOM(Figure of Merit)과 형평성(Fairness)에서 기존의 폐루프 전력 제어 방식보다 월등한 성능을 입증하였다. 또한 게임 이론을 적용한 전력 제어 방식은 통신 환경을 인지하고 연산하여 적합한 최적의 서비스를 제공하는 CR의 여러 분야에 확장 적용 가능함을 제시하였다.

• 한국전문물리치료학회지
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• 제6권3호
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• pp.11-21
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• 1999

Human balance is maintained through a complex process involving sensory detection of body motions, integration of sensorimotor information within the central nervous system, and execution of appropriate musculoskeletal responses. The basic task of balance is to position the body center of gravity (COG) over some portion of the support base. When the COG extends beyond the base of support, the person has exceeded the limits of stability (LOS). At this point, a step or stumble is required to prevent a fall. Automatic postural responses operate to keep the COG over the base of support. They are a set of functionally organized, long-loop responses that act to keep the body in a state of equilibrium. There are four commonly identified automatic postural responses, or strategies. These are ankle strategy, hip strategy, suspensory (knee) strategy, and stepping strategy. Thus, the purpose of this study was to evaluate the LOS using various knee strategies. Forty subjects participated in this study. The subjects were comprised of 20 males and 20 females who were without neurologic, orthopaedic or balance performance impairments. The LOS was measured with a Balance Performance Monitor (BPM) Dataprint Software Version 5.3. The results of this study were as follows: 1) Knee joint angle which is to increase stability of standing balance with using knee strategy was at mid-range. 2) There were statistically significant differences in anteroposterior LOSs according to the knee strategy. 3) There were no statistically significant differences in mediolateral LOSs according to the knee strategy. 4) There were statistically significant differences of anteroposterior LOSs with using knee strategy according to gender. 5) There were no statistically significant differences in mediolateral LOSs with using knee strategy according to gender.

• 근관절건강학회지
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• 제5권2호
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• pp.238-252
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• 1998

Reumatic arthritis is a disease with joint pain being one of the key symptoms. The patient suffers from the pain, stiff sensation and edema due to the inflammation taking Place In one or more joints. Accompanying these problems are fatigue, unusual exhaustion, fever, tachycardia and weakness. Inaddition, joints are often deformed and muscles shrink along with the progress of edema, coupled with depression and psychological instability resulting from the loss of the mobile function and limitations on the daily life. Some patients become fed up with the long and hard flight with the disease and just give up, which aggravates the symptoms. Others come to the hospital only when the conditions have become serious. We need to prevent these and guide the patients in the right direction. Against this backdrop, this study aims to look into the relations between the knowledge on the part of the patients together with their feeling of self-efficacy and the compliance. The results are expected to help the patients improve their life, In addition to providing useful materials for setting up appropriate plan for nursing intervention. The study was conducted by distributing questionnaire to 88 patients selected from the out-patient department of a university hospital in Inchon, from April 6 to 27, 1998. The following tools were used the yardstick of self-efficacy, developed in 1997 by the Society for the Health of Rheumatism Patients, was used for measuring the levels of knowledge and the feeling of self-efficacy. The degree of compliance was measured by the data collected from documents in addition to the results of the analysis of the interviews with the patients. The reliability of the tools was confirmed. In the analysis, the general characteristics were expressed in figures and percentages. The levels of knowledge, feeling of self-efficacy, and compliance were expressed in the average values and standard deviations. The relations among the variables following the general characteristics were analysed by the t-test and one-way ANOVA. The Pearson correction coefficient was used for the analysis of factors. Multiple-loop analysis was used to identify the variables affecting the compliance. The following are the results of this study. 1. Among the 88 patients, 18 were men and the remaining 70 were women, with a ratio 1 : 3.87. Regarding the age groups, 23 were between 50 and 59 years old, with those between 50 and 69 accounting for 51.1% of the total. High school graduates or higher amounted to 58%. Religious patients was 67% or 59 persons. Fifty nine percent were unemployed, and 58.3% (49 persons) had two children or fewer. The period of suffering from rheumatism varied between 2 months and IS years, with 70% less than years. 2. The average figure In relation to the of knowledge was 17.63 points over 30 or 58. 76%, which means a medium level. 3. The average figure of the feeling of self-efficacy was 60.06 points. 4. The level of compliance was 3.26, which was above average. 5. The relation between the feeling of self-efficacy and compliance showed an "r" value of 0.37, which was significant. It means that the higher the feeling, the greater the compliance points. 6. The analysis of the knowledge level revealed that the difference is found only between the college graduates and junior-high graduates or lower. 7. The feeling of self-efficacy varied along with the age and education level. 8. The general characteristics of patients as discussed above did not show significant difference with the compliance. 9. Regarding the elements influencing the compliance, the number of children, period of suffering, income, age, feering of self-efficacy, knowledge, and compliance had 54% of significance. In conclusion, rheumatism victims can lead a better life if they are appropriately educated, based on efficient training program from the early days of the disease ; if they become able to manage themselves thanks to the training ; and if they are helped by a program focusing on the increase of the feeling of self-efficacy aimed at changing patient's behavior.

• 대한기계학회논문집A
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• 제40권11호
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• pp.979-986
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• 2016

등속조인트의 일종인 트리포드 축은 동력전달용으로 고속열차의 KTX와 KTX-산천에 모두 적용되고 있으며, 동력대차에서 모터 감속장치(MRU)와 차축 감속장치(ARU)를 연결해 고속회전동력을 전달하는 핵심 요소이다. 축 방향의 미끄럼 운동이 가능한 트리포드 축은 열차 구동을 위한 토크를 전달하며, 동력전달 시스템에 과토크 발생 시 축의 퓨즈부가 절단되어 동력을 차단한다. 본 연구에서는 리니어 액추에이터를 이용한 대용량 비틀림 시험장치의 개발과 이를 이용한 트리포드 축의 정적 비틀림 강도와 피로수명을 확인하고자 하였다. 또한 구조해석을 통해 축의 취약부를 파악하고 비틀림 피로해석 결과와 실제 피로시험의 결과를 비교분석하여 비틀림 성능 개선을 위한 설계안을 제시하고자 하였다. 한편 트리포드 축의 피로에 따른 열화를 파악하기 위해 히스테리시스 곡선을 이용하였으며, 히스테리시스 곡선의 기울기 변화를 통해 피로고장 시점을 확인하였다.

• 대한정형외과스포츠의학회지
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• 제1권2호
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• pp.118-123
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• 2002

목적: 저자들은반월상연골후내각부에사용되던기존의inside-out 의수술수기를변형하여수직봉합이가능하면서충분한고정력을얻을수있는수술수기를보고하는바이다. 수술수기: 관절경을전외측도달법으로위치시키고봉합용갈고리를전내측도달법으로위치시켜봉합용갈고리를돌려서내측반월상연골후내각부에파열된부분의내측의대퇴골쪽표면에서경골쪽표면으로통과시킨다. 갈고리내로PDS $\#0$을통과시킨후봉합용갈고리를빼내고전내측도달법입구로PDS$\#0$의양끝을뽑아낸다. 전내측도달법입구에관절경을위치시킨후전외측도달법입구로Zone specific cannula를통과시켜반월상연골파열면의경골면에위치시키고저자가고안한Looped Needle을통과시킨 후 경골면의PDS $\#0$을Looped Needle의loop 사이를통과시킨후관절밖으로빼낸다.대퇴골면의PDS $\#0$도같은방법으로관절밖으로빼낸다. 2개의PDS 봉합사가나온입구근처에약1cm가량의incision 을넣고PDS 봉합사사이에연부조직이끼지않음을확인하고결찰을시행한다. 고찰: 변형된inside-out 봉합술은기존의inside-out 봉합술에비해수술시간의지연이있을수있으나, 수직봉합을할수있고견고한고정력을얻을수있으며해부학적인정복으로파열부위의접촉면을증가시켜후내각반월상연골의파열을봉합하는우수한방법으로판단되어보고하는바이다.

• 대한관절경학회지
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• 제4권2호
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• pp.97-104
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• 2000

목적 : 대부분의 후방 십자 인대 부전시 후방 십자 인대 다발이 남아 있어 골-슬개건-골 이식 후방 십자 인대 재건술을 할 때 이식물의 원활한 통과를 위해 이들을 완전히 제거하는 경우가 많았다. 이 연구의 목적은 후방 경격막 도달법을 이용하여 후방 십자 인대의 경골 터널을 정확히 만들고, 남아 있는 후방 십자 인대 다발을 유지하면서 관절경 하 후방 십자 인대 재건술을 시행하고 임상적 결과를 보고하고자 한다. 대상 및 방법 : 1993년 11월부터 1999년 6월까지 저자에 의해 후방 경격막 도달법을 이용하여 실시된 관절경하 후방 십자 인대 재건술 44례 중 1년 이상의 추시가 가능하였던 37례를 대상으로 하였다. 환자들의 평균 연령은 31.8세(최저 14세, 최고 56세)였으며 추시 기간은 평균 17.8개월(최단 12개월, 최장 61개월)이었다. 이식물로 이중 고리 자가 슬괵건 29례, 이중 고리 동종 슬괵건 4례, 동종 아킬레스 건-골 이식 4례가 이용되었다. 결과 : 술전 보였던 주관적 증상은 많이 소실되었으며 Lysholm 점수는 술 전 평균 60.4, 술 후 평균 88.1로, KT 관절계 검사는 술 전 평균 11.0mm, 술 후 평균 2.3mm로 향상되었다. 술 후 시행한 자기공명촬영술상 이식물은 남아 있는 후방 십자 인대 조직과 하나의 인대로 유합되는 소견을 보였다. 결론 : 후방 경격막 도달법을 이용하여 정확한 위치에 경골 터널을 만들 수 있으며, 남아 있는 후방 십자 인대 다발은 이식물과 함께 치유되어 좋은 결과를 얻었다.