• Korean Journal of Psychosomatic Medicine
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• v.24 no.2
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• pp.133-139
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• 2016

Objectives : As the prevalence of elderly depression increases, it becomes urgent problem to provide preventive and management measures. But in practice, it is difficult to detect depression in early stage. The purpose of this study is to evaluate the association between sociodemographic factors and depression in elderly welfare facility users in a city. Methods : In this research, the severity of depression and sociodemographic factors(gender, age, education, co-morbid disease, housing type, number of children, number of family members living with the subjects) was evaluated through PHQ-9 and interview. Using the data, the associations of depression and sociodemographic factors were analyzed. Based on PHQ-9 depression cut-off value(10 points), the subjects were divided into two groups, and the difference of the variables between groups were analyzed statistically. Results : 'Own house'(YES/NO), education(less than elementary school graduation/more than elementary school graduation) were sociodemographic factors which showed significance difference in mean PHQ-9 scores. Group with Over PHQ-9 10 points showed less 'having their own house' and less education level than group with less PHQ-9 10 points. Conclusions : With this research, it is expected that the risk factors for the elderly depression can be understood and the measures for early detection and invention of elderly depression would be provided.

• Korean Journal of Psychosomatic Medicine
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• v.27 no.1
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• pp.13-24
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• 2019

Objectives : The goals of the study are how to establish the cohort systems for the children and adolescents victims with sexual abuse in Korea and to identify the risk and protective factors that influence mental health in child sexual abuse (CSA). This is initial assessment data based on the analysis of cohort variables for baseline evaluation of subjects. Methods : We constructed the cohort systems for CSA victims recruited by Seoul Sunflower Children Center, CSA victims protection center. The initial assessment data which consisted of demographic and psychological inventories of CSA victims and their parents/families, psychiatric diagnoses were the results of statistical analysis of 65 subjects under 19 years old for 3 years 7 months. Results : The initial data were followings : female participants, N=56; mean age, 11.6 (SD=4.5); the most sexual assault, molestation 71.8%; victims, family and acquaintance 87.1%; 61.5% of the subjects diagnosed with psychiatric disorder; 29.2% diagnosed with PTSD and 23.1% diagnosed with depression. Mean duration for abuse to report is 1.5 years. Mean score of IES-R-K, TSCYC-avoidant and CBCL-problematic behavior were increased above clinical cut-off. Conclusions : CSA victims tend to have high risks in mental health problem. The cohort study could provide the risk and protective factors of CSA in mental health, and construct the predictive model for mental illness in Korea.

• Psychiatry investigation
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• v.15 no.11
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• pp.1046-1052
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• 2018

Objective The aims of the present study were to explore the occurrence of childhood trauma and importantly to determine the impacts of childhood trauma on psychosocial features in a Chinese sample of young adults. Methods A survey was carried out in a group of 555 university students by using Childhood Trauma Questionnaire (CTQ), Self-rating Depression Scale (SDS), Self-rating Anxiety Scale (SAS), Dysfunctional Attitudes Questionnaire (DAS), Eysenck Personality Questionnaire (EPQ), and Social Support Rating Scale (SSRS). The moderate-severe cut-off scores for CTQ were used to calculate the prevalence of childhood trauma, and then psychosocial features were compared between individuals with and without childhood trauma. Results A proportion of 18.6% of university students had self-reported childhood trauma exposures. Subjects with childhood trauma reported higher scores of SDS, SAS, DAS, and psychoticism and neuroticism dimensions of EPQ (t=4.311-5.551, p<0.001); while lower scores of SSRS and extraversion dimension of EPQ (t=-4.061- -3.039, p<0.01). Regression analyses further revealed that scores of SAS and DAS were positively (Adjusted B=0.211-0.230, p<0.05), while scores of SSRS were negatively (Adjusted B=-0.273- -0.240, p<0.05) associated with specific CTQ scores. Conclusion Childhood trauma is still a common social and psychological problem. Individuals with childhood trauma show much more depression, anxiety, distorted cognition, personality deficits, and lower levels of social support, which may represent the social and psychological vulnerability for developing psychiatric disorders after childhood trauma experiences.

• Korean Chemical Engineering Research
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• v.56 no.6
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• pp.890-894
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• 2018

In this study, methylene blue which is one of dye materials was introduced as active material for aqueous redox flow battery. The redox potential of methylene blue was shifted to negative direction as pH increased. The full-cell performance was evaluated by using methylene blue as the negative active material and vanadium as the positive active material with acid supporting electrolytes. The cell voltage of methylene $blue/V^{4+}$ is very low (0.45 V). In addition, the maximum solubility of methylene blue in water is only 0.12 M. Therefore, the cell test was performed with very low concentration (0.0015 M methylene blue, $0.15M\;V^{4+}$) at first time. Cut-off voltage range was 0 to 0.8 V and $1mA{\cdot}cm^{-2}$ current density was adopted during cycling. As a result, current efficiency (CE) was 99.67%, voltage efficiency (VE), 88.83% and energy efficiency (EE) was 85.87% and discharge capacity was ($0.0500Ah{\cdot}L^{-1}$) at 4 cycle. In addition, the cell test was performed with increased concentration (0.1 M methylene blue, $0.15M\;V^{4+}$) with $10mA{\cdot}cm^{-2}$ current density, leading to higher discharge capacity ($3.8122Ah{\cdot}L^{-1}$) with similar efficiency (CE=99%, VE=85%, EE=85% at 4 cycle).

• Journal of Advanced Navigation Technology
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• v.22 no.6
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• pp.602-609
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• 2018

Differential GPS (DGPS) is known as a positioning method using pseudo range correction (PRC) which is communicating between a refence receiver and moving receivers. In real world, a moving receiver loses communication with the reference receiver, resulting in loss of PRC real-time communication. In this paper, we assume that the transmission of the pseudo range correction isinterrupted in the middle of real-time positioning situations, in which calibration information is received in the DGPS method. Under the disconnected communication, we propose 'predict DGPS' that real-time virtual PRC model which is modeled by a machine learning algorithm with previously acquired PRC data from a reference receiver. To verify predict DGPS method, we compared and analyzed positioning solutions acquired from real PRC and the virtual PRC. In addition, we show that positioning using the DGPS prediction method on a real road can provide an improved positioning solution assuming a scenario in which PRC communication was cut off.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.541-550
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• 2019

An emergency generator is key equipment for fire-fighting to supply power to fire-fighting facilities, which protect property and people in cases of fire accidents. A rated load test for emergency generators must be carried out by connecting an emergency load to the generator in accordance with related regulations. However, a no-load test has been performed for emergency generators in general since serious problems can occur when the main power is cut off, including the damage of customer devices and shut down of critical loads. Therefore, this paper proposes a load test method for an emergency generator using energy storage system (ESS) without the interruption of main power. The emergency power system was also modeled based on PSCAD/EMTDC software, and a 200-kW scale ESS load test device was implemented. The simulation and test results show that the load test method is useful and practical for an emergency power supply system.

• Anxiety and mood
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• v.15 no.2
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• pp.115-121
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• 2019

Objective : The purpose of this study was to investigate prevalence of psychiatric symptoms and determine predictors of emotional distress of military hospital surgical patients. Methods : This study examined 104 orthopedic patients admitted to the Armed Forces Military Hospital September-November 2018. For the study, every subject completed self-assessment inventories regarding depressive and anxiety symptoms (Hospital Anxiety and Depression Scale), sleep problems (Pittsburgh Sleep Quality Index), problematic alcohol and tobacco use (Cut off, Annoyed, Guilty, Eye-opener screening), and psychiatric history. We performed the Student's t-test and the chi-square test for the collected data to investigate the prevalence of psychiatric symptoms, including emotional distress. Logistic regression analysis was used to examine the risk factors related to emotional distress of hospitalized military personnel. Results : There were no significant differences in socio-demographic and psychiatric symptoms between soldiers and officers. The prevalence of depressive and/or anxiety symptoms (emotional distress) was 21.2% (n=21). In the logistic regression analysis, psychiatric history [Adjusted Odds Ratio (AOR)=18.99 ; 95% Confidence Interval (CI)=1.42-253.57 ; p=0.026] and low military life satisfaction (AOR=15.67; 95% CI=1.46-168.11 ; p=0.023) correlated with emotional distress. Conclusion : Soldiers admitted to the military hospital showed similar prevalence of emotional distress as those at general hospitals. Considering military circumstances, it is necessary to detect and intervene regarding soldiers with a psychiatric history and low military life satisfaction to promote mental health at military hospitals.

• Journal of the Korean Institute of Landscape Architecture
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• v.46 no.6
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• pp.17-25
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• 2018

This study was conducted to calculate the optimum height of trees, estimating a model for the prediction of tree growth for the landscape improvement of the Gyeonghoeru area. For the verification of measures for management, this study conducted a photographic survey of the Gyeonghoeru area and used the Pressler's formula to examine the growth rate of the pine forest of Mansesan. The results of the study are as follows. First, as a result of a field survey and landscape analysis, trees in the Gyeonghoeru area are large ones with more than a diameter at breast height of 30cm, except for weeping cherry trees and persimmon trees, and especially, it is necessary to manage them or replace with small trees through the landscape of Mansesan, which screens the landscape and pruning the trees in the terraced flower garden in the north. Second, as a result of a measurement of the growth rate of trees, for 10 years on average, they grew up by 14% in source diameter and 5% in tree height 5% in south of Mansesan and by 7% in source diameter and 2.4% in tree height in the north of Mansesan. Furthermore, when a simulation was prepared based on the measured growth rate of trees, it was found out that 20 years later, on the landscape on the second floor of Gyeonghoeru, the pine forest of Mansesan would cut off the skyline of Mt. Inwang-san. Third, this study analyzed a landscape improvement simulation and proposed a plan for tree management to take a view of the landscape of the Gyeonghoeru area. This study has a significance that it drew an efficient planting maintenance policy, considering the landscape characteristics of the Gyeonghoeru area.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.2
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• pp.165-173
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• 2019

Lithium anodes (13, 15, 17, and 20 wt% Li) were fabricated by mixing molten lithium and iron powder, which was used as a binder to hold the molten lithium, at about $500^{\circ}C$ (discharge temp.). In this study, the effect of applied pressure and lithium content on the discharge properties of a thermal battery's single cell was investigated. A single cell using a Li anode with a lithium content of less than 15 wt% presented reliable performance without any abrupt voltage drop resulting from molten lithium leakage under an applied pressure of less than $6kgf/cm^2$. Furthermore, it was confirmed that even when the solid electrolyte is thinner, the Li anode of the single cell normally discharges well without a deterioration in performance. The Li anode of the single cell presented a significantly improved open-circuit voltage of 2.06 V, compared to that of a Li-Si anode (1.93 V). The cut-off voltage and specific capacity were 1.83 V and $1,380As\;g^{-1}$ (Li anode), and 1.72 V and $1,364As\;g^{-1}$ (Li-Si anode). Additionally, the Li anode exhibited a stable and flat discharge curve until 1.83 V because of the absence of phase change phenomena of Li metal and a subsequent rapid voltage drop below 1.83 V due to the complete depletion of Li at the end state of discharge. On the other hand, the voltage of the Li-Si anode cell decreased in steps, $1.93V{\rightarrow}1.72V(Li_{13}Si_4{\rightarrow}Li_7Si_3){\rightarrow}1.65V(Li_7Si_3{\rightarrow}Li_{12}Si_7)$, according to the Li-Si phase changes during the discharge reaction. The energy density of the Li anode cell was $807.1Wh\;l^{-1}$, which was about 50% higher than that of the Li-Si cell ($522.2Wh\;l^{-1}$).

• Journal of Korean Neurosurgical Society
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• v.62 no.4
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• pp.450-457
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• 2019

Objective : Anterior cervical discectomy and fusion (ACDF) is commonly used surgical procedure for cervical degenerative disease. Among the various intervertebral spacers, the use of allografts is increasing due to its advantages such as no harvest site complications and low rate of subsidence. Although subsidence is a rare complication, graft collapse is often observed in the follow-up period. Graft collapse is defined as a significant graft height loss without subsidence, which can lead to clinical deterioration due to foraminal re-stenosis or segmental kyphosis. However, studies about the collapse of allografts are very limited. In this study, we evaluated risk factors associated with graft collapse. Methods : We retrospectively reviewed 33 patients who underwent two level ACDF with anterior plating using allogenous bone graft from January 2013 to June 2017. Various factors related to cervical sagittal alignment were measured preoperatively (PRE), postoperatively (POST), and last follow-up. The collapse was defined as the ratio of decrement from POST disc height to follow-up disc height. We also defined significant collapses as disc heights that were decreased by 30% or more after surgery. The intraoperative distraction was defined as the ratio of increment from PRE disc height to POST disc height. Results : The subsidence rate was 4.5% and graft collapse rate was 28.8%. The pseudarthrosis rate was 16.7% and there was no association between pseudarthrosis and graft collapse. Among the collapse-related risk factors, pre-operative segmental angle (p=0.047) and intra-operative distraction (p=0.003) were significantly related to allograft collapse. The cut-off value of intraoperative distraction ${\geq}37.3%$ was significantly associated with collapse (p=0.009; odds ratio, 4.622; 95% confidence interval, 1.470-14.531). The average time of events were as follows: collapse, $5.8{\pm}5.7months$; subsidence, $0.99{\pm}0.50months$; and instrument failure, $9.13{\pm}0.50months$. Conclusion : We experienced a higher frequency rate of collapse than subsidence in ACDF using an allograft. Of the various preoperative factors, intra-operative distraction was the most predictable factor of the allograft collapse. This was especially true when the intraoperative distraction was more than 37%, in which case the occurrence of graft collapse increased 4.6 times. We also found that instrument failure occurs only after the allograft collapse.