• 천문학회보
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• 제42권2호
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• pp.81.4-82
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• 2017

We investigate velocity oscillations in the active region plage by using the high-spatial, high-spectral and high-temporal resolution spectral data acquired by the Interface Region Imaging Spectrograph (IRIS). From the Mn I $2801.907{\AA}$ (lower chromosphere), C II (lower transition region) and Si IV (middle transition region) lines, we measure the line of sight Doppler velocity at different atmospheric layers, and present results of wavelet analysis of the plage region with a range of periods from 2 to 8 minutes. In addition, we present correlations of the oscillations from the lower chromosphere to the middle transition region. Finally, we will discuss the regional dependence of the oscillation properties on physical properties such as temperature and magnetic field inclination.

• 한국지리정보학회지
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• 제14권4호
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• pp.182-193
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• 2011

지역 규모에 따른 한국 남부해역 표층 수온의 시 공간적 변동 패턴을 비교하고자 시기적으로는 31년간(1980~2000)의 동계와 하계를, 지역적으로는 남부해역 전체 해역(A 지역)을 비롯하여 제주도를 중심으로 서부 해역(B 지역)과 동부 해역(C 지역) 등 세 해역을 선정하였다. 수온의 시간적 변동 패턴을 위해서는 회귀분석을, 수온의 공간적 변동패턴 분석을 위해서는 수온의 가중평균중심과 표준편차타원체 분석이 각각 적용되었다. 수온의 회귀분석 결과 세 지역에서 두계절 모두 장기적으로 상승하는 경향을 보였다. 하지만 31년 평균수온이 하계에는 세 지역 모두 유사하였지만, 동계에는 C 지역이 B 지역보다 높게 나타났다. 두 계절 수온의 공간적 변동 패턴은 세 지역에서 각기 다름을 보였다. A 지역에서는 동-서 방향, B 지역에서는 남동-북서 방향, C 지역에서는 남서-북동 방향으로 나타났다. 아울러 동계에 수온의 가중평균중심 위치와 평균 수온과의 관계가 A와 B 지역에서는 상관성이 있는 반면, C 지역에서는 상관성이 없게 나타났다. 따라서 수온의 시 공간적 변동패턴 분석 시 지역적 규모를 고려해야 함을 알 수 있다.

• Earthquakes and Structures
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• 제15권6호
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• pp.605-616
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• 2018

In this paper, an extended Cloud analysis method is developed for seismic fragility assessment of existing highway bridges in the southeast Queensland region. This method extends the original Cloud analysis dataset by performing scaled Cloud analyses. The original and scaled Cloud datasets are then paired to generate seismic fragility curves. The seismic hazard in this region is critically reviewed, and the ground motion records are selected for the time-history analysis based on various record selection criteria. A parametric highway bridge model is developed in the OpenSees analysis software, and a sampling technique is employed to quantify the uncertainties of highway bridges ubiquitous in this region. Technical recommendations are also given for the seismic performance evaluation of highway bridges in such low-to-moderate seismic zones. Finally, a probabilistic fragility study is conducted by performing a total of 8000 time-history analyses and representative bridge fragility curves are generated. It is illustrated that the seismic fragility curves generated by the proposed extended Cloud analysis method are in close agreement with those which are obtained by the rigorous incremental dynamic analysis method. Also, it reveals that more than 50% of highway bridges existing in southeast Queensland will be damaged subject to a peak ground acceleration of 0.14 g.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2273-2278
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• 2007

Brazed Plate Heat Exchanger (BPHE) is a type of compact plate heat exchanger with parallel corrugated plates which are brazed together in series. Each plate hascorrugation called herringbone pattern. Inside a BPHE, hot fluid and cold fluid alternate its flow direction to establish counter current flow configuration. Two-phase flow heat transfer and pressure drop of R-22 in BPHE were experimentally measured in this study. In the present experiments, single-phase region and two-phase region coexist in a BPHE. Therefore, the inside of a BPHE have to be divided into single phase region and two phase region and analyzed accordingly. The results from the single phase flow analysis are then extended to the two phase flow analysis to correlate the condensation and evaporation heat transfer and pressure drop for the refrigerant R-22 in the BPHEs. Previous models for two- phase friction factor have been compared with the present experimental results.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2000년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2000
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• pp.440-447
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• 2000

In order to evaluate the cost effectiveness of seismic isolation for bridges in low and moderate seismic region, a method of calculation minimum life-cycle cost of seismic-isolated bridges under specific acceleration level and soil condition is developed. Input ground motion is modeled as spectral density function compatible with response spectrum for combination of acceleration coefficient and site coefficient. Failure probability is calculated by spectrum analysis based on random vibration theories to simplify repetitive calculations in the minimization procedure. Ductility of piers and its effects on cost effectiveness are considered by stochastic linearization method. Cost function and cost effectiveness index are defined by taking into consideration the characteristics of seismic isolated bridges. Limit states for calculation of failure probability are defined on superstructure, isolator and pier, respectively. The results of example design and analysis show that seismic isolation is more cost-effective in low and moderate seismic region than in high seismic region.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.582-585
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• 2003

Sequence analysis indicated that Bacillus polymyxa MGL21 CFTase was divided into five distinct regions. CFTase contained three regions of repeat sequences at the N-terminus and C-terminus. The endo-inulinase region of homology (ERH) of CFTase was similar to that of Pseudomonas mucidolens endo-inulinase. Furthemore, CFTase possessed a highly conserved core region. In order to understand the role of the core region on the function of CFTase from B. polymyxa MGL21 CFTase ${\Delta}NC$ was prepared. The molecular weight of the purified wild type CFTase and $CFTase{\Delta}NC$ were 148kDa, 90kDa, respectively.

• Journal of Advanced Marine Engineering and Technology
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• 제25권3호
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• pp.573-580
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• 2001

When investigating optimum design of the evaporator in the refrigeration and heat pump systems, there is still lack of data for the dynamic characteristics of the evaporator, This is due to the fact that the static characteristics in the evaporator are absolutely difficult to measure and are burdened with uncertainties. In this study, the simulation works for static characteristics in the evaporator of small air conditioner are carried out to obtain the data of dynamic characteristics. In the simulation, the test evaporator is divided by two-phase evaporating region and single-phase heating region. The major parameters are refrigerant flow rate, heat transfer coefficient of air, air velocity and air temperature. The results show that the calculation method for tube length is an easy-to-use to model analysis of static characteristics and to determine state of refrigerant in the evaporator. The effects of the four parameters on the length of evaporating completed point and heat flow rate to the evaporator are clarified.

• 대한가정학회지
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• 제36권11호
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• pp.43-59
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• 1998

The purpose of this study was to analyze the residential preferences, the type of house, the size of living space, and the region for later life and contributing factors to their housing plan. The sample in this study consisted of 572 aged couple living in Korea. Statistics employed for the analysis were frequencies, means, X2test, logit analysis and multiple regression. The results could be summarized as follows. They preferred 31.2 pyung as living space, the single detacted house(81.1%) and living in middle-small cities or rural area. The present living space, present living area, satisfaction of economic status had significant effects on the living space in later life. Those who had a plan to live in the single detached house were affected by husband's educational attaintment, the type of present house, present and future living region. And the factors affecting furture living region were present living region, household income, household expenditure, total asset and preferred housing type. The affecting factors were different from future residential preferences by occupation and health status.

• 농촌계획
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• 제16권3호
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• pp.67-76
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• 2010

The objective of this study is to investigate a priority and selection of agricultural specialization items from Daegu and Gyeongbuk region by using analytical tools such as, the Analytic Hierarchy Process(AHP) and the Scoring Method. The results of this study are as follows; 1) Five major items were selected for each region based on Daegu and Gyeongbuk regional agricultural performances. 2) The results of AHP analysis, Daegu and Gyeongbuk's agricultural experts evaluated the weight of three decision-elements(objectiveness 0.35, efficiency 0.341, identity 0.309) and seven decision-elements. 3) Results of AHP and Scoring Method analysis, Investigated a priority of agricultural specialization 3 items in 25 cities and districts Daegu and Gyeongbuk regional agricultural performances. 4) Finally, The results of this study will provide basic information on agricultural specialization policy in Daegu and Gyeongbuk region.

• 전력전자학회논문지
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• 제19권5호
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• pp.463-469
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• 2014

This paper proposes a maximum torque operation strategy for the direct torque control of a surface-mounted permanent-magnet synchronous motor (SPMSM). The proposed method analyzes the available operation region of the stator flux of the SPMSM under voltage and current constraints. Based on this analysis, the optimal stator flux trajectory that yields the maximum torque is obtained across the entire operation region, including constant torque and constant power regions. The proposed strategy is also applicable in the flux-weakening region II operation of the SPMSM, which has no speed limit. The validity of the proposed method is verified through experiments conducted on an 800 W SPMSM drive system.