• Journal of the Korean Society of Industry Convergence
• /
• v.23 no.1
• /
• pp.65-71
• /
• 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.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.15 no.5
• /
• pp.687-698
• /
• 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.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.1A
• /
• pp.66-74
• /
• 2007

Cognitive Radio system can guarantee available channel whenever, wherever by sensing surrounding channel condition. Therefore, there is a strict rule that have to use allocated channel efficiently without any interference from incumbent User. In this paper, to avoid interference which can occur during uplink transmission in CR system, we propose reporter using scheme which informs incumbent user's situation to adjacent cell to limit channel usage. Therefore, we can use more channel in each cell without interference. With this scheme we can expect better throughput using more channel in a large space with same resource.

• Advances in materials Research
• /
• v.6 no.3
• /
• pp.245-255
• /
• 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
• /
• v.14 no.11
• /
• pp.6955-6959
• /
• 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.

• Journal of the Korean Dietetic Association
• /
• v.9 no.1
• /
• pp.32-39
• /
• 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.

• Journal of The Korean Society of Integrative Medicine
• /
• v.10 no.2
• /
• pp.73-83
• /
• 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.

• Korean Journal of Exercise Nutrition
• /
• v.15 no.4
• /
• pp.173-182
• /
• 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.

• Korean Journal of Psychosomatic Medicine
• /
• v.20 no.2
• /
• pp.91-97
• /
• 2012

Objectives : With the increase in cancer prevalence, the health behavior of cancer survivors has become an important issue. This study was conducted to examine the psychosocial correlates of behavior changes after cancer diagnosis. Methods : 95 patients completed questionnaires assessing depression, anxiety, insomnia, posttraumatic stress symptoms, social constraints, personal beliefs about cancer cause and health-related behavior changes after cancer diagnosis. Results : In the multiple logistic regression analysis, insomnia was the only significant predictor of positive change in physical behavior : normal sleep group(Odds ratio=9.462, 95% CI 1.738-51.509) and subthreshold insomnia group(Odds ratio=10.529, 95% CI 1.701-65.161) showed a larger increase compared to the insomnia group. In psychosocial behavior, low age, religion and causal belief in hormonal factors were independent factors that predicted increase in positive change. Conclusions : This study showed a difference between predictors of physical and psychosocial health behavior change after breast cancer diagnosis. Multi-faceted approaches are required to promote positive change in health behavior in cancer patients.

• Journal of Korean Medicine Rehabilitation
• /
• v.21 no.2
• /
• pp.1-13
• /
• 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.