• 한국산업융합학회 논문집
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• 제23권1호
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• pp.65-71
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• 2020

Recently, interest in the DC transmission is rapidly increasing worldwide. In many countries and leading companies are prior to the aggressive development of HVDC technology and application. Especially, VSC-HVDC system has been widely applied to transfer power at long distance between power plant and power consumption area. Therefore in this paper, we analyzed the benefit-cost of VSC-HVDC system which has more advantages than existing transmission system. The proposed system is MMC(Modular Multilevel Converter) VSC-HVDC system that have stability of Power Grid, interconnect Large-scale New Power Generation Plants by prevents Blackout. And MMC VSC-HVDC system Reduced the loss importing foreign systems. And the benefits were calculated in four stages, and the costs were applied to the actual project. By evaluating the various avoidance costs compared to the benefit-cost, it was confirmed that MMC VSC-HVDC system was advantageous in system stability and economic and social benefits.

• 한국군사과학기술학회지
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• 제15권5호
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• pp.687-698
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• 2012

LADAR systems can rapidly acquire 3D point clouds by sampling the target surfaces using laser pulses. Such point clouds are widely used for diverse applications such as DSM/DTM generation, forest biomass estimation, target detection, wire avoidance and so on. Many kinds of LADAR systems have been developed with their respective purposes and applications. Particularly, Geiger mode imaging LADAR systems are increasingly utilized since they are energy efficient thank to extremely sensitive detectors incorporated into the systems. The purpose of this research is the performance assessment of a Geiger mode imaging LADAR system based on simulation with the real system parameters. We thus developed a simulation method of such a LADAR system by modeling its geometric, radiometric, optic and electronic aspects. Based on the simulation, we performed the performance assessment of a newly designed system to derive the outlier ratio and false alarm rate expected during its operation in almost real environment with reasonable system parameters. The proposed simulation and performance assessment method will be effectively utilized for system design and optimization, and test data generation.

• 한국통신학회논문지
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• 제32권1A호
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• pp.66-74
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• 2007

Cognitive Radio System은 주변 환경을 인지하여 시간적, 공간적으로 가용할 수 있는 채널을 확보하여 사용하는 시스템이다. CR시스템은 Incumbent User에 대한 간섭이 없는 조건 하에서 이용 가능한 채널을 효율적으로 써야한다는 엄격한 규정이 있다. 본 논문에서는 CR시스템에서 상향링크에서 일어날 수 있는 간섭을 회피하기 위한 방법으로 Reporter를 이용하여 이웃 셀로 Incumbent user의 상황을 보고하여 채널이용을 제한함으로서 간섭이 없는 상태에서 각 셀에서 보다 많은 채널을 이용하기 위한 방안을 알아본다. 이를 통해 같은 resource에 대해 보다 공간적으로 넓은 지역에서 채널을 이용할 수 있어 보다 높은 throughput을 확보할 수 있었다.

• Advances in materials Research
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• 제6권3호
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• pp.245-255
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• 2017

High energy ball milling is employed to produce iron matrix- multiwall carbon nanotube (MWCNT) reinforced composite. The damage caused to MWCNT due to harsh ball milling condition and its influence on interfacial bonding is studied. Different amount of MWCNT is used to find the optimal percentage of MWCNT for avoidance of the formation of chemical reaction product at the matrix - reinforcement interface. Effect of process control agent is assessed by the use of different materials for the purpose. It is observed that ethanol as a process control agent (PCA) causes degradation of MWCNT reinforcements after milling for two hours whereas solid stearic acid used as process control agent, allows satisfactory conservation of MWCNT structure. It is further noted that at a high MWCNT content (~ 2wt.%), high energy ball milling leads to reaction of iron and carbon and forms iron carbide (cementite) at the iron-MWCNT interface. At low percentage of MWCNT, dissolution of carbon in iron takes place and the amount of reinforcement in iron matrix composite becomes negligibly small. However, under the present ball milling condition (ball to metal ratio~ 6:1 and 200 rpm vial speed) iron-1wt.% MWCNT composite of good interfacial bonding can retain the tubular structure of reinforcing MWCNT.

• Asian Pacific Journal of Cancer Prevention
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• 제14권11호
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• pp.6955-6959
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• 2013

The incidence of hepatocellular carcinoma (HCC) is relatively high in Southeast Asia. Globally, HCC has a high fatality rate and short survival. The objectives of this retrospective cohort study were to review the epidemiology and survival of HCC patients at a tertiary centre in north-east of Peninsular Malaysia. Subjects were adult HCC patients diagnosed by histopathology or radio-imaging. Secondary liver carcinoma was excluded. Kaplan Meier and multiple Cox proportional hazard survival analyses were used. Only 210 HCC cases from years 1987-2008, were included in the final analysis. The number of cases was increasing annually. The mean age was 55.0 (SD 13.9) years with male:female ratio of 3.7:1. Approximately 57.6% had positive hepatitis B virus, 2.4% hepatitis C virus, 20% liver cirrhosis and 8.1% chronic liver disease. Only 2.9% had family history and 9.0% had frequently consumed alcohol. Most patients presented with abdominal pain or discomfort and had hepatomegaly, 47.9% had an elevated ${\alpha}$-fetoprotein level of 800 IU/ml or more, 51.9% had multiple tumors and 44.8% involved multiple liver lobes. Approximately 63.3% were in stage 3 and 23.4% in stage 4, and 82.9% did not receive any treatment. The overall median survival time was 1.9 months (95% confidence interval (CI): 1.5, 2.3). The 1-month, 6-month, 1-year and 2-year survival rates were 71.8%, 23.3%, 13.0% and 7.3% respectively. Significant prognostic factors were Malay ethnicity [Adjusted hazard ratio (AHR) 1.6; 95%CI: 1.0, 2.5; p=0.030], no chemotherapy [AHR 1.7; 95%CI: 1.1, 2.5; p=0.017] and Child-Pugh class C [AHR 2.6; 95%CI: 1.4, 4.9; p=0.002]. HCC in our study affected a wide age range, mostly male, in advanced stage of disease, with no treatment and very low survival rates. Primary prevention should be advocated in view of late presentation and difficulty of treatment. Vaccination of hepatitis virus and avoidance of liver toxins are to be encouraged.

• 대한영양사협회학술지
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• 제9권1호
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• pp.32-39
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• 2003

Although medical nutrition therapy (MNT) is considered as a cornerstone of medical treatment for hypercholesterolemia, few studies have evaluated medical and economical outcome of MNT. This study was conducted to identify whether MNT administered by registered dieticians could lead to a beneficial clinical and cost outcome in persons with hypercholesterolemia. A prospective clinical trial was carried out at outpatient clinics, which involved an initial visit with a dietitian followed by another visit at first 4 weeks during the 6 weeks study periods. Thirty-nine subjects took part in a 6 weeks nutrition intervention program. Clinical and economical outcomes were compared before and after MNT. Medical nutrition therapy lowered total serum cholesterol level 6.1% (P<0.05), low-density lipoprotein cholesterol (LDL-C) 9.4% (P<0.05) and high-density lipoprotein cholesterol (HDL-C) 3.0% (P<0.05). The cost-effective ratio was ￦ 1,520/cholesterol mg/dl and ￦ 1,441/LDL-cholesterol mg/dl, respectively. After dietitian's intervention, lipid drug eligibility was obviated in 16 of 39(41%) subjects. The cost savings from the avoidance of lipid medications was ￦ 151,107 per patient annually. In conclusion, it is suggested that provision of systemic intensive nutritional care for persons with hypercholesterolemia has significant effects on serum cholesterol reduction and clinical cost savings.

• 대한통합의학회지
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• 제10권2호
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• pp.73-83
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• 2022

Purpose : Low back pain (LBP) is reported as a risk of experiencing musculoskeletal disorders due to muscle stiffness and hypokinetics. The lumbar spine in an unstable state causes imbalance and lumbar instability. Therefore, This study examined the effects of lumbar stabilization exercise and self-complex exercise program on pain, function, psychosocial level, static balance ability, and transverse abdominal muscle (TrA) thickness and contraction ratio in patients with lumbar instability. Methods : The design of this is a randomized controlled trial (RCT). Twenty-six LBP patients participated in this study. Screening tests were performed and assigned to the experimental group (n=13) and control group (n=13) using a random allocation program. Both groups underwent a lumbar stabilization exercise program. In addition, the experimental group implemented the self-complex exercise program. All interventions were applied three times per week for four weeks. The quadruple visual analog (QVAS), the Korean version of the Oswestry disability index (K-ODI), Korean version of fear-avoidance belief questionnaire (FABQ), static balance ability, TrA thickness, and contraction ratio were compared to evaluate the effect on intervention. Statistical significance was set at 𝛼=.05. Results : Both groups showed significant differences before and after the intervention in QVAS, K-ODI, FABQ, static balance ability, and TrA thickness in contraction (p<.05). In addition, significant differences in K-ODI and FABQ were observed between the experimental group and control group (p<.05). Conclusion : A lumbar stabilization exercise and self-complex exercise program resulted in reduced dysfunctions, psychosocial stability in patients with lumbar instability. Therefore, Lumbar stabilization exercise and self-complex exercise program for patients with lumbar instability are effective method with clinical significance in improving the function and psychosocial stability.

• 운동영양학회지
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• 제15권4호
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• pp.173-182
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• 2011

Post-traumatic stress disorder (PTSD) is a stress-related mental disorder induced by severe external stressors such as assault, disaster or severe accident. We investigated the effects of treadmill exercise on short-term memory in relation to apoptosis and cell proliferation in the hippocampus following PTSD. Stress to the pregnant rats was induced by exposure of maternal rats to the hunting dog in an enclosed room. Exposure time was 10 min, repeated three times per day, with 1 hour interval. Exposure of maternal rats to the hunting dog was continued 7 days after pregnancy until delivery. The pregnant rats in the exercise groups were forced to run on a treadmill for 30 min once a day for the same duration of stress exposure. Step-down avoidance task for short-term memory, western blot for Bcl-2, Bax, and immunohistochemistry for caspase-3, 5-bromo-2'-deoxyuridine (BrdU), and Ki-67 were conducted. Maternal rats exposed to stress during pregnancy showed short-term memory impairment. Expressions of Bax, Bcl-2, ratio of Bax to Bcl-2, and caspase-3 in the hippocampus were increased in the PTSD rats. Cell proliferation in the hippocampal dentate gyrus was decreased in the PTSD rats. Treadmill exercise alleviated short-term memory impairment and suppressed expressions of Bax, the ratio of Bax to Bcl-2, and caspase-3. Treadmill exercise also increased cell proliferation. The present results indicate that treadmill exercise alleviated PTSD-induced short-term memory impairment by suppressing apoptotic cell death and enhancing cell proliferation in the hippocampus.

• 정신신체의학
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• 제20권2호
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• pp.91-97
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• 2012

목 적 : 암의 유병율 증가와 함께 암 생존자의 건강 행동에 대한 이해가 중요해지고 있다. 본 연구는 암 진단 후 신체 및 심리사회적 건강 행동의 변화와 관련된 여러 심리사회적 요인들을 분석하였다. 방 법 : 유방암 환자 95명을 대상으로 우울, 불안, 불면, 외상후 스트레스 증상, 사회적 제약, 자신의 암의 원인에 대한 생각 및 건강 행동에 대해 자가보고식 설문조사를 수행하였다. 결 과 : 신체적 행동 변화에 대한 다중 회귀분석에서 불면만이 유의한 연관성을 보여 정상수면군(Odds ratio=9.462, 95% CI 1.738-51.509)과 역치하 불면증군(Odds ratio=10.529, 95% CI 1.701-65.161)에서 불면증을 겪는 군보다 더 높은 증가를 보였다. 심리사회적 건강 행동 변화에서는 낮은 연령, 종교를 가진 경우, 호르몬 요인과 암과 관련이 있다고 믿을수록 증가하였다. 결 론 : 유방암 환자의 건강 행동 변화에 기여하는 요인들은 건강 행동 영역별로 차이를 보인다. 긍정적 변화를 유도하기 위해 영역별로 다른 접근이 필요함을 시사한다.

• 한방재활의학과학회지
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• 제21권2호
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• pp.1-13
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• 2011

Objectives : We investigated the effect of Haein-tang(Hairen-tang) on short-term memory and apoptosis in dentate gyrus of the gerbils with transient global ischemia. Methods : For the induction of cerebral ischemia model in mice, common carotid arteries of gerbils were occluded with aneurysm clips for 5 min. One day after operation, Haein-tang(Hairen-tang) was administrated orally injected once a day for 15 consecutive days. Gerbils were randomly divided into four group(n=10 in each group): sham-operation group, ischemia-induction group, ischemia-induction and 50 mg/kg Haein-tang(Hairen-tang)-treated group, ischemia-induction and 100 mg/kg Haein-tang(Hairen-tang)-treated group, and ischemia-induction and 200 mg/kg Haein-tang(Hairen-tang)-treated group. The effect of Haein-tang(Hairen-tang) on memory function was investigated by using step-down avoidance task. Apoptosis was confirmed by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling(TUNEL) staining and immunohistochemistry for caspase-3. Western blot analysis for the expressions of Bax and Bcl-2 protein was also conducted. Results : 1. Haein-tang extract significantly enhanced short-term memory in step-down avoidance task and 100 mg/kg, 200 mg/kg Haein-tang-treated group. 2. Haein-tang extract significantly suppressed TUNEL-positive cells after transient global ischemia and 50 mg/kg, 100 mg/kg, 200 mg/kg Haein-tang-treated group. 3. Haein-tang extract significantly increased caspase-3 positive cells in the hippocampal dentate gyrus after transient global ischemia and 50 mg/kg, 100 mg/kg, 200 mg/kg Haein-tang-treated group. 4. Haein-tang extract significantly decreased Bax protein expressions in the hippocampus after transient global ischemia and 100 mg/kg, 200 mg/kg, Haein-tang-treated group. Haein-tang extract significantly increased Bcl-2 protein expressions in the hippocampal dentate gyrus after transient global ischemia and 50 mg/kg, 100 mg/kg, 200 mg/kg, Haein-tang-treated group. Haein-tang extract significantly decreased Ratio of Bax protein to Bcl-2 protein in the hippocampus after transient global ischemia and 100 mg/kg, 200 mg/kg Haein-tang-treated group. Conclusions : While Haein-tang(Hairen-tang) treatment improved short-term memory by suppressing on ischemia-induction apoptosis. In the present study, Haein-tang(Hairen-tang) shows protective effect on transient global ischemia.