• Journal of Ecology and Environment
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• 제35권2호
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• pp.79-89
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• 2012

This study was conducted with the intention of clarifying the effects of land-use types on a species of ground beetle's richness, abundance, and composition; the study focused on urban landscapes. We also selected the potential bioindicators classifying land-use types; eleven sites were selected from an urban landscape in Korea. Overall, land-use types in urban landscapes did not appear to cause significant decrease in species richness or the abundance of total ground beetle assemblage. According to habitat preferences, several land-use types and distances from the forest significantly affected the species richness and abundance, while the open-habitat species were not affected by these variables. Land-use types were classified into two major groups, forest and non-forest areas, based on ground beetle assemblage; several indicators, such as $Dolichus$ $halensis$ $halensis$ and subfamily Carabinae species, were of particular consideration. In conclusion, environmental change by anthropogenic disturbance can cause different effects on ground beetle assemblages, and forest specialists can be negatively affected.

• Structural Engineering and Mechanics
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• 제28권4호
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• pp.411-442
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• 2008

Ground motions in near source region of large crustal earthquakes are significantly affected by rupture directivity and tectonic fling. These effects are the strongest at longer periods and they can have a significant impact on Engineering Structures. In this paper, it is aimed to determine near-fault ground motion effects on the nonlinear response of dams including dam-reservoir-foundation interaction. Four different types of dam, which are gravity, arch, concrete faced rockfill and clay core rockfill dams, are selected to investigate the near-fault ground motion effects on dam responses. The behavior of reservoir is taken into account by using Lagrangian approach. Strong ground motion records of Duzce (1999), Northridge (1994) and Erzincan (1992) earthquakes are selected for the analyses. Displacements, maximum and minimum principal stresses are determined by using the finite element method. The displacements and principal stresses obtained from the four different dam types subjected to these nearfault strong-ground motions are compared with each other. It is seen from the results that near-fault ground motions have different impacts on the dam types.

• KIEAE Journal
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• 제10권4호
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• pp.75-80
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• 2010

Generally, ground-source heat pump (GSHP) systems have a higher performance than conventional air-source systems. However, the major fault of GSHP systems is their expensive boring costs. Therefore, it is important issue that to reduce initial cost and ensure stability of system through accurate prediction of the heat extraction and injection rates of the ground heat exchanger. Conventional analysis methods employed by line source theory are used to predict heat transfer rate between ground heat exchanger and soil. Shape of ground heat exchanger was simplified by equivalent diameter model, but these methods do not accurately reflect the heat transfer characteristics according to the heat exchanger geometry. In this study, a numerical model that combines a user subroutine module that calculates circulation water conditions in the ground heat exchanger and FEFLOW program which can simulate heat/moisture transfer in the soil, is developed. Heat transfer performance was evaluated for 3 different types ground heat exchanger(U-tube, Double U-tube, Coaxial).

• 한국안전학회지
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• 제33권1호
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• pp.81-87
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• 2018

The seismic response, the natural frequencies and the mode shapes of an offshore wind turbine with twisted tripod substructure subject to various pile-ground interactions are discussed in this paper. The acceleration responses of the tower head by four historical earthquakes are presented as the seismic response, while the other loads are assumed as ambient loads. For the pile-ground interactions, the fixed, linear and nonlinear models are employed to simulate the interactions and the p-y, t-z and Q-z curves are utilized for the linear and nonlinear models. The curves are designed for stiff, medium and soft clays, and thus, the seven types of the pile-ground interactions are used to compare the seismic response, the acceleration of the tower head. The mode shapes are similar to each other for all types of pile-ground interactions. The natural frequencies, however, are almost same for the three clay types of the linear model, while the natural frequency of the fixed support model is quite different from that of the linear interaction model. The wind turbine with the fixed support model has the biggest magnitude of acceleration. In addition, the nonlinear model is more sensitive to the stiffness of clay than the linear pile-ground interaction model.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 봄 학술발표회 논문집
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• pp.433-438
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• 2001

The response spectrum has been widely used to differentiate the significant characteristics of earthquake ground motion and to evaluate the response of structures under ground shaking. Current design response spectrum is based on Seed, Ugas, and Lysmer's study. (1976) In this study, earthquake ground motion data sets adopted by Seed, Miranda, and Riddell is analyzed regards to soil types. And how earthquake data sets effected the design response spectrum is evaluated using acceleration-displacement response spectrum.

• 식물병연구
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• 제30권1호
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• pp.34-49
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• 2024

The development of sustainable smut management techniques requires an understanding of the impacts of smut on sugarcane growth and the relationships between smut intensity and meteorological variables, varieties, and crop types. Thus, assessments were made with the objectives to 1) determine the effect of smut on the above-ground growth of sugarcane, and 2) quantify the association of smut with weather variables, varieties and crop types. The effect of smut on above-ground growth was assessed in six fields planted with NCo 334 (wider coverage) having 6 months of age in Fincha and Metehara fields in 2021. Data on above-ground growth were taken from 20 randomly selected smut-affected and healthy stools from each field. Besides, 6 years' data (2015 to 2021) on the numbers of smut-affected stools and smut whips of 79 fields were collected. Furthermore, 10 years' (2011 to 2021) weather data were acquired from the sugar plantations. The results demonstrated reduction in the above-ground growth of sugarcane in the range of 18.39% and 73.42% due to smut. In addition, weather variables explained about 68.48% and 66.58% of the variability in the number of smut-affected stools and whips respectively. Smut intensity increased with crop types for susceptible varieties. The tight association between the smut epidemic and crop types, varieties, and weather, implied that these parameters must be carefully considered in management decisions. Continuous monitoring of smut disease, meteorological variables, varieties, and crop types in all the sugarcane plantations could be done as a part of integrated smut management in the future.

• 한국터널지하공간학회 논문집
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• 제21권2호
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• pp.227-242
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• 2019

토압식(Earth Pressure-Balanced, EPB) 쉴드 TBM 기계데이터 분석을 통해 토사터널의 특징이 반영된 막장 전방 예측 방법을 제안하였다. 기존에 암반과 토사가 혼합된 복합 지반의 예측에 적용하였던 시계열 분석 모델을 토사터널에 적용가능하도록 수정하였다. 또한 수정된 모델을 사용하여, 토사 종류에 따라 쏘일 컨디셔닝 재료를 선택하는 것이 타당한지 연구하였다. 이를 위해 Self-Organizing Map (SOM) 군집화(clustering) 분석을 수행하였다. 그 결과 무엇보다도 지반타입이 #200체 통과량 35% 기준으로 분류되어야 한다는 것을 확인하였다. 또한 TBM 기계데이터 분석을 통해 수정된 모델이 지반 타입을 예측하는데 사용될 수 있음을 확인하였다. 수정된 기준에 따라 지반 타입을 분류하고 시계열 분석을 수행하면, 10막장 전방 지반에 대해서 98%의 높은 예측 정확도를 보였으며, 이를 통해 수정된 방법의 우수성이 입증되었다. 특히 지반 타입 변화 구간에 대한 예측 정확도도 약 93%로, 10막장 전방에서 지반 타입 변화 여부를 미리 확인할 수 있게 되었다.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.459-463
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• 2003

A circularly polarized microstrip patch antenna (MPA) using electromagnetic (EM) coupled fed method is analyzed in view of the two types of coupling mechanisms viz. cavity and parasitic type, proposed earlier. The patch-ground plane distance is varied in order to achieve the fore-mentioned types of couplings. For each case of patch-ground plane distance, the offset position of feedline is optimized for perfect matching and the boresight axial ratio (AR) is observed. It is seen that CP operation is possible only for cavity-type coupling (smaller patch-ground plane distances). The simulated results for the boresight AR for the two types of coupling mechanisms are presented.

• 한국지하수토양환경학회지:지하수토양환경
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• 제7권3호
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• pp.45-59
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• 2002

본 연구의 목적은 국가 지하수 관측망 자료를 활용하여 우리나라 지하수위 변동 곡선의 유형을 구분하고, 각 유형별 함양률을 평가하여 지하수 함양률의 공간적 변동성을 규명하는 데 있다. 전국 지하수의 수위 변동 곡선을 구분하기 위하여 요인 분석 방법을 사용했으며 그 결과 총 5 개의 유형으로 구분하였다. 유형별 함양률은 95.44%의 신뢰도 수준에서 6.2 %(유형 I), 4.1 %(유형 II), 9.2 %(유형 III), 5.8 %(유형 IV), 15.3 %(유형 V)로 추정되었으며 한 유형에서도 관측 지점별로 약 6 %의 변화폭을 보였다. 지하수위 변동 곡선법을 이용하여 유역별로 지하수 함양률을 평가한 결과 한강과 금강 유역에서는 각각 강수량 대비 10.0 %, 8.3 %의 함양률을 보였고, 낙동강 및 영산강·섬진강 유역에서는 각각 6.1 %, 6.6 %의 함양률을 보였으며 기저유출법에 의해서 유역별로 함양률을 추정한 연구의 결과와 유사하게 나타났다 따라서 본 연구를 통하여 지하수 함양률이 수위 변동 곡선의 유형별 혹은 유역별로 변동성을 가짐을 규명할 수 있었다.

• 디지털융복합연구
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• 제18권2호
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• pp.483-487
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• 2020

본 연구는 지면의 유형에 따른 서스펜션 트레이닝의 효과를 분석하기 위해 14명의 건강한 남자 대학생을 대상으로 2종류의 다른 지면 편평한 지면, 짐볼을 이용한 불안정한 지면에 따른 서스펜션 트레이닝의 주목적인 코어 근육의 활성 특성을 연구하였다. 지면의 유형에 따른 코어 근육의 활성도를 측정하기 위해 EMG(Electromyography)를 활용하였고 측정부위는 복직근, 외복사근, 내복사근, 하부요추 기립근의 근활성도를 측정하였다. 측정변인은 각각의 코어 근육 별로 지면의 유형에 따라 근전도 신호를 표준화하기 위해 %MVC방법으로 측정하였다. 지면의 유형에 따른 코어 근육의 차이를 검증하기 위해 paired t-test를 실시하였으며 유의수준은 p<. 05로 설정하였다. 다양한 유형의 지면에 따른 코어 근육의 활성도에 관한 특성을 측정한 결과 두 지면 사이의 근육 별, 지면 별 차이점은 통계적으로 유의하게 나타나지 않았다. 하지만 이는 코어 근육의 트레이닝의 적용 시 반드시 불안정한 형태의 지면에서의 트레이닝 효과가 안정된 지면에서의 효과보다 우월하다는 통념을 다시 한 번 생각하게 하는 중요한 결과라 사료된다. 본 연구의 의미는 불안정한 지면이나 안정된 지면이 코어 근육 활성화에 큰 영향을 미치지 않으므로 어떠한 운동프로그램이던지 정규화된 코어근육 강화프로그램을 실시해도 근육의 활성화에 차이가 없음을 의미한다.