• Korean Journal of Applied Biomechanics
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• v.18 no.4
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• pp.49-57
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• 2008

The purpose of this study was to determine the effects of 12-week elastic resistance exercise for the elderly on the magnitude of frequency and variability of ground reaction force signals. To this aim, total 12 elderly women aged in their 70 were participated in this study and asked to do a 12-week elastic resistance exercise program. FFT(fast Fourier Transform) was used to analyze the frequency domain analysis of the ground reaction forces's signals and an accumulative PSD (power spectrum density) normalized by support phase of walking was calculated to reconstruct the certain signals. To estimate the gait stability between the before and after exercise, values of variability were determined in a coefficient of variance. The magnitude of frequency and variability analysis for media-lateral signal revealed significantly less after exercise (p<.05). In contrast, variability of this signal's frequency that have used to evaluate the local stability during walking exhibited significantly greater after exercise(p<.05). In summary, magnitude frequency and variability of media-lateral ground reaction force's signal were significantly changed after a 12-week elastic resistance exercise.

• Fisheries and Aquatic Sciences
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• v.6 no.4
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• pp.209-212
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• 2003

Lucigenin (Lg)- and luminol (Lm)-dependent chemiluminescence (CL) was used to compare the respiratory burst of rockfish (Sebastes schlegeli) phagocytes after stimulation with phorbol myristate acetate (PMA). To establish which reactive oxygen species (ROS) contributes to the observed CL, the modulators of ROS metabolism, such as superoxide dismutase (SOD), catalase, and sodium azide $(NaN_3)$ were used. Although LgCL responses were inhibited significantly by the addition of either SOD or catalase, in comparison to the control, significantly lower LgCL responses were recorded by SOD than catalase. LmCL also showed significantly decreased responses by the addition of SOD and catalase. However, there were no statistical differences in CL responses between SOD and catalase additions. More profound and significant decrease of LmCL responses were recorded by simultaneous addition of SOD and catalase. Sodium azide markedly enhanced LgCL responses, while it significantly inhibited LmCL responses. These results indicate that LgCL and LmCL can be used to measure extracellular $O_2$ production and myeloperoxidase (MPO)-mediated ROS production in fish phagocytes, respectively. Furthermore, LmCL can be used for analyzing intracellular ROS production by simultaneous addition of both SOD and catalase.

• Journal of the Korean Data and Information Science Society
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• v.28 no.1
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• pp.29-37
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• 2017

It has gradually become important to estimate a forest stand volume utilizing LiDAR data. Recently, various statistical models including a linear regression model has been introduced to estimate a forest stand volume using LiDAR data. One of limitations of the current approaches is in that the accuracy of observed forest stand volume data, which is used as a response variable, is questionable unstable. To overcome this limitation, we consider a spatial structure for a forest stand volume. In this research, we propose a hierarchical model for applying a spatial structure to a forest stand volume. The proposed model is applied to the LiDAR data and the forest stand volume for Bonghwa, Gyeongsangbuk-do.

• International Journal of Concrete Structures and Materials
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• v.9 no.3
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• pp.369-379
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• 2015

Friction in a post-tensioning system has a significant effect on the distribution of the prestressing force of tendons in prestressed concrete structures. However, attempts to derive friction coefficients using conventional electrical resistance strain gauges do not usually lead to reliable results, mainly due to the damage of sensors and lead wires during the insertion of strands into the sheath and during tensioning. In order to overcome these drawbacks of the existing measurement system, the Smart Strand was developed in this study to accurately measure the strain and prestressing force along the strand. In the Smart Strand, the core wire of a 7-wire strand is replaced with carbon fiber reinforced polymer in which the fiber Bragg grating sensors are embedded. As one of the applications of the Smart Strand, friction coefficients were evaluated using a full-scale test of a 20 m long beam. The test variables were the curvature, diameter, and filling ratio of the sheath. The analysis results showed the average wobble and curvature friction coefficients of 0.0038/m and 0.21/radian, respectively, which correspond to the middle of the range specified in ACI 318-08 in the U.S. and Structural Concrete Design Code in Korea. Also, the accuracy of the coefficients was improved by reducing the effective range specified in these codes by 27-34 %. This study shows the wide range of applicability of the developed Smart Strand system.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.1
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• pp.65.2-65.2
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• 2012

세계전파통신회의 (WRC; World Radiocommunication Conference)회의는 국제전기통신연합 (ITU)에서 규정하는 국제 전파법 제개정을 위해, 3-4년 간격으로 개최되는 전파통신 관련 최고회의라고 할 수 있다. WRC-12회의는 2012년 1월 23일 - 2월 17일에 걸쳐 스위스 제네바에서 WRC-07회의가 개최되었다. 본 회의에서는 전세계의 국가별 전파사용을 둘러싼 정치적, 경제적 이권 다툼이 치열하게 진행되었으며, 25개의 WRC 의제들에 대해 국제전기통신 연합 산하의 연구반 (ITU-R Study Group)의 연구결과를 토대로 관련 국제전파규약들을 최종적으로 개정하였다. 따라서 국내 전파천문대의 입장에서는 상기 회의의 의제 가운데 국내전파천문대의 원활한 운용과 사용주파수 대역의 보호를 위해 필요한 우리나라의 기고서를 발표하였다. 그 결과 국내의 전파천문대 운영과 관련된 22 GHz 대역이라든지 ALMA용의 275GHz 이상 대역, 달탐사용의 37GHz 대역 등에 대한 신규주파수 또는 보호조건 강화 등이 완료되었다. 본 발표에서는 WRC-12회의에서 결정된 최종결과 및 이들이 국내전파천문대의 향후 운영에 미치는 영향을 보고하고자 한다. 또한 차기 WRC-15회의를 위해 새로 제정된 의제들 가운데 전파천문을 비롯한 과학업무 관련 의제 소개 및 대응책 검토를 하고자 한다.

• Korean Journal of Biological Psychiatry
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• v.13 no.2
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• pp.95-102
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• 2006

Object : Nerve growth factor(NGF) is a protein involved in neuronal survival and plasticity in the central nervous system, which might play an important role in stress, depression and suicide. This study was performed to determine whether there is an alteration in plasma NGF concentrations in depressed patients with suicidal attempt. Methods : The subjects were 32 depressed patients who attempted suicide and admitted in emergency room. Forty-four hospitalized non-suicidal depressive patients and the 30 normal controls were closely matched with the suicidal group in terms of age and sex. Individuals in all 3 groups were evaluated independently by a semi-structured interview for the purpose of establishing a DSM-IV criteria diagnosis. The severity of depressive symptoms was evaluated using Hamilton depression rating scale(HDRS). The severity of the suicidal behavior was evaluated by Weisman and Worden's risk-rescue rating(RRR) system and the Lethality Suicide Attempt Rating Scale(LSARS). Plasma NGF level was measured by the enzyme linked immunosorbent assay(ELISA) method. Results : There were no statistically significant differences of the plasma NGF levels among groups. LSARS and RRR did not reveal any significant correlation with ${\beta}$-NGF level in suicidal depressive patients. Conclusion : This study do not support an association between ${\beta}$-NGF and suicidal depression. However it is necessary to investigate this association through other route such as postmortem brain.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.3
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• pp.16-22
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• 2010

The gas turbine engine performance relies greatly on its component performance characteristics. Generally, engine manufacturers do not provide engine purchasers the component performance characteristics which can be obtained by lots of experimental tests at various operating conditions and big amount of expenses. In previous works the component maps have mostly been generated by scaling from a similar component map. However this scaling method has large error at off design points, specially in high altitude operation. Therefore this work proposes an inverse modeling method that can generate components maps of PT6A-67A turboprop engine using performance data provided by the engine manufacturer. In addition, evaluation can be made through comparison between performance analysis results using the performance simulation program including the generated compressor map and performance data.

• Journal of Korean Society on Water Environment
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• v.24 no.6
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• pp.741-749
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• 2008

Many small-scale ponds that serve as ecological habitat, recreation and irrigation are faced to eutrophication problem, which causes aesthetic nuisance and ultimately loss of their functions. Thus accurate evaluation of the trophic state of these ponds is essential to provide rational information to the stakeholders so that they can develop effective management actions. In this study, the trophic state of a small pond (Wonheung) that experiencing water quality degradation due to vicinity land development was assessed using various Trophic State Indexes (TSIs) and statistical analysis including Principal Components Analysis (PCA) based on the field monitoring data obtained from May to December, 2007. The results showed that the pond is under eutrophic state with average total nitrogen (T-N) and total phosphorus (T-P) concentrations of $708.1{\mu}g/L$ and $59.3{\mu}g/L$, respectively. The factor loading plot obtained from PCA showed distinct two influencing factors, PC 1 and PC 2. PC 1 was grouped by T-P, Chlorophyll a (Chl-a), suspended solids (SS), TN/TP ratio, and transparency that all strongly related to the eutrophication state, while PC 2 by temperature, conductivity, dissolved oxygen (DO) and turbidity that explains the seasonal water quality variations. The limiting factor was identified as light rather than phosphorus by both T-N/T-P ratio and TSI indexes analysis. The results and methodology adopted in this study can be used for water quality assessment for other small ponds and lakes.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.88.2-88.2
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• 2010

세계전파통신회의 (WRC; World Radiocommunication Conference)회의는 국제전기통신연합 (ITU)에서 발행하는 국제 전파법과 관련된 전파규약을 갱신하거나 새로운 법 제정을 위해, 3-4년 간격으로 개최되는 전파통신 관련 회의라고 할 수 있다. WRC-12회의는 2012년 1월 23일 -2월 17일에 걸쳐 스위스 제네바에서 개최되며, 동회의의 원활한 진행을 위하여, 25개의 WRC 의제들에 대한 ITU 산하의 연구반 (ITU-R Study Group) 연구결과들을 기술보고서로 확정하기 위한 회의(CPM-11, Conference Preparatory Meeting)가 2011년 2월 14일-25일에 걸쳐 스위스 제네바에서 역시 개최된다. 이에 한국천문연구원에서는 KVN과 일본국립천문대(ASTRO-G)간의 원활한 국제 공동 VLBI연구를 위해, WRC회의에서 최종적인 규정개정을 함에 있어서 필요한 CPM기술문서작성과 관련된 ITU-R 연구반 회의에서 주도적인 역할을 수행하고 있다. 따라서 본 발표에서는 2010년 6월 10-18일에 걸쳐 스위스 제네바에서 진행되었던 ITU-R WP7B, 7D 회의에서, 우리나라가 전파천문업무와 관련된 기술문서 개정사항에 대하여 제출하였던 제안결과 및 회의 주요 결과를 소개하고, 전파천문업무 보호 및 22 GHz 대역 달탐사, 38 GHz 대역 Space-VLBI운용대역과 관련된 WRC-12 의제 1.6, 1.11, 1.12 등에 대한 향후 대응방안을 알아보고자 한다.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.87.2-87.2
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• 2010

세계전파통신회의 (WRC; World Radiocommunication Conference)회의는 국제전기통신연합 (ITU)에서 발행하는 국제 전파법과 관련된 전파규약을 갱신하거나 새로운 법 제정을 위해, 3-4년 간격으로 개최되는 전파통신 관련 회의라고 할 수 있다. WRC-12회의는 2012년 1월 23일 -2월 17일에 걸쳐 스위스 제네바에서 개최되며, 동회의의 원활한 진행을 위하여, 25개의 WRC 의제들에 대한 ITU 산하의 연구반 (ITU-R Study Group) 연구결과들을 기술보고서로 확정하기 위한 회의(CPM-11, Conference Preparatory Meeting)가 2011년 2월 14일 -25일에 걸쳐 스위스 제네바에서 역시 개최된다. 이에 한국천문연구원에서는 275 GHz 이상 대역에서의 전파천문업무의 원활한 운용을 위해, WRC회의에서 최종적인 규정개정을 함에 있어서 필요한 CPM기술문서작성과 관련된 ITU-R 연구반 회의에서 주도적인 역할을 수행하고 있다. 따라서 본 발표에서는 2010년 6월 10-18일에 걸쳐 스위스 제네바에서 진행되었던 ITU-R WP7B, 7D 회의에서, 우리나라가 전파천문업무와 관련된 기술문서 개정사항에 대하여 제출하였던 제안결과 및 회의 주요 결과를 소개하고, 전파천문업무 보호 및 22 GHz 대역 달탐사, 38 GHz 대역 Space-VLBI운용대역과 관련된 WRC-12 의제 1.6, 1.11, 1.12 등에 대한 향후 대응방안을 알아보고자 한다.