• Structural Engineering and Mechanics
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• 제81권1호
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• pp.59-68
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• 2022

Prestressed prefabricated hollow core concrete slabs with spans of 5 m and 10 m are commonly used since last century and still in service due to the advantage of construction convenience and durability. However, the end slabs are regularly subjected to cracks at the top and fail with brittleness due to the asymmetric boundary conditions. To better maintain such widely used type of hollow core slabs, the effect of asymmetric constraint in the end slabs are systematically studied through detailed nonlinear finite element analyses and experimental data. Experimental tests of slabs with four prestressed tendons and seven prestressed tendons with different boundary conditions were conducted. Results observe three failure modes of the slabs: the bending failure mode, shear and torsion failure mode, and transverse failure mode. Detailed nonlinear finite element models are developed to well match the failure modes and to reveal potential damage scenarios with asymmetric boundary conditions. Recommendations regarding ultimate capacity of the slabs with asymmetric boundary conditions are made to ensure a safe and rational design of prestressed concrete hollow slabs for short span bridges.

• Ocean and Polar Research
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• 제24권3호
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• pp.189-196
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• 2002

A multichannel seismic survey was conducted in the southern Ayu Trough which is the only spreading boundary between the Philippine Sea and Caroline plates. The seismic system used in this study comprises of 2.46-l sleeve gun and a 12-channel streamer with a group interval of 6.25m. Migration technique was used to analyze seismic velocity, and poststack depth migration was applied to the stacked data. The sediment thickness obtained from the depth section tends to increase with distance from the spreading axis. Sedimentation rates are poorly constrainted in the study area. The apparent half-spreading rates estimated from the sediment thickness and sedimentation rate from DSDP hole on the caroline plate are 4.7mm/yr and 7.9mm/yr at $1^{\circ}24'N\;and\;0^{\circ}42'N$, respectively, which are fester than Previously suggested. On the basis of new oblique spreading geometry, the recalculated spreading rates are 5.4mm/yr and 9.1mm/yr at $1^{\circ}24'N\;and\;0^{\circ}42'N$, respectively. Seismic sections show that the topography is asymmetric across the Ayu Trough and the acoustic basement is rough. These features are consistent with the earlier suggestion that the Ayu Trough is a slow-spreading divergent boundary. A detailed examination of seismic profiles away from the axis shows that sediments can be divided into two layers which implies a possible change in the spreading rate anuor sedimentation condition during the formation of the trough.

• 환경영향평가
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• 제22권5호
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• pp.455-466
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• 2013

The aim of this study is to seek application plans of National Ecosystem Survey database based on comparison and examination of feasible analysis methods for distribution characteristics of alien plants. In order to set up a correlation analysis method between alien plants and environmental factors, we had reviewed the 3rd National Ecosystem Survey guide book and consequently, two kinds of analysis method were tested. One was 1/25,000 scale map boundary based analysis and the other was representative mountain area based analysis. In this study we restricted the research area to select reliable surveyed database from whole "2011 National Ecosystem Survey flora database" according to two major criteria. First, an area defined by 1/25,000 scale map boundary and representative mountain area where the number of surveyed flora records should be within top 20%. Second, land cover map should also be built up inside that area. As a result, 25 map boundaries and 25 representative mountain areas were extracted to be analyzed. To limit a boundary for every representative mountain area we had analyzed distribution of environmental factors around that area by manual inspection with SPOT-5 remote sensed satellite image then designated 3km buffer zone from each alien plant location in that area. After then, naturalized index (NI) and urbanized index (UI) was calculated and correlations analysis was carried out. With the result of correlation analysis by map boundary only agricultural land area showed significant value of r (0.4~0.6, correlated) and the rest of factors did not. In the case of representative mountain area, the result showed that agricultural land, road and forest area showed significant value of r (0.6~0.8, highly correlated) which was corresponding to existing researches. Therefore, representative mountain area based method is preferable when using the alien plants database of National Ecosystem Survey for species distribution analysis. And also, considering the way of database utilization is strongly suggested at the first stage of survey planning for promoting active use of national ecosystem survey database.

• 지식경영연구
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• 제20권1호
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• pp.133-153
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• 2019

Due to the uncertainty of dynamic business environment, modern organizations have been giving attention to dynamic capabilities beyond traditional notion of core competence. Among them, absorptive capacity and boundary-spanning activity are considered the most important. The former refers to activities regarding acquisition, assimilation, transformation and exploitation of internal and external knowledge. The latter is composed of boundary-loosening and boundary-tightening activities to detect internal or external information and then to preserve, protect, or acquire resources. Thus, both have achieved wide recognition as a potential source of change and innovation. This study investigated the cross-level relation between boundary-spanning leadership at team level and absorptive capacity at individual level. We also explored self-efficacy and extra-role behavior that can affect employees' absorptive capacity. To test multi-level analysis, the survey data were collected from 862 members in 137 teams of different firms. Results revealed that boundary-spanning leadership had the positive cross-level impact on absorptive capacity in the team context. Moreover, absorptive capacity was positively associated with self-efficacy and extra-role behavior at individual level. Based on these findings, we provided theoretical and practical implications to address rapidly changing environments and discussed limitations of this paper for further research.

• 자원환경지질
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• 제30권4호
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• pp.363-369
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• 1997

As a part of the study to know the deep geological structure of the Ogcheon Zone. gravity survey is performed along the survey line of which direction is roughly perpendicular to major faults of the Zone. Recent studies for petrology. geochemistry. and structural geology in south-western Ogcheon Zone are outlined. Raw gravity data are corrected to obtain Bouguer anomalies and the anomalies are interpreted to obtain subsurface structures along the survey line. The subterranean density discontinuities determined from the power spectrum method are appeared at depths of 15.4 km and 2.8 km. It is considered that the depth of 15.4 km indicates the boundary between upper and lower crust. Probably the depth of 2.8 km represents the boundary between upper volcanic formations and granites. Alternatively. the observed Bouguer anomalies are interpreted in terms of lateral density variation model. Finally. the subterranean geological structure to satisfy the Bouguer anomalies is presented through the iterative forward method in which results obtained from surface geological informations and from the inverse method are adopted as an initial model.

• 한국산학기술학회논문지
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• 제16권11호
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• pp.7855-7862
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• 2015

지적도면정보는 필지단위로 소재지, 지번, 지목, 경계 등의 일정한 사항을 지적측량 등에 의해 등록함으로써 생성된다. 그러나 전산화된 지적도면정보는 경계점좌표가 소수점 3자리인 mm 단위의 등록과 소수점 2자리인 cm 단위로 이원화되어 등록되고 있어 지적행정과 지적측량에 혼란을 초래하고 있다. 본 연구에서는 지적도면정보의 좌표등록과 면적산정에 대한 문제점 분석을 통하여 지적도면정보 좌표등록의 소수점 자리수 통일방안을 제시하고자 하였다. 소수점 자리수에 의한 면적의 변화량을 실험한 결과 토지이동으로 인한 면적의 변동과 미세폴리곤의 발생은 좌표의 등록을 소수점 2자리의 등록을 소수점 3자리로 변경한다면 해결이 가능함을 제시할 수 있었고, 이를 위해 제도적으로 소수점 3자리까지 등록할 수 있도록 법을 개정하여 운용하여야 함을 제시하였다.

• 한국측량학회지
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• 제32권spc4_2호
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• pp.393-400
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• 2014

"지적재조사 기본계획"에는 2012년에 수행된 정부의 예비타당성조사 결과가 반영되어 2030년까지 약 1조 3,000억 원의 국가재정을 지적재조사사업에 투입할 것을 계획하고 있다. 지적재조사사업의 사업비 중 78.8%를 차지하고 있는 지적재조사측량을 효율적으로 사업추진하는 것이 전체 지적재조사사업의 효율화에 매우 중요하다. 현재 "지적재조사 기본계획" 상 지적확정측량으로 계획된 13%의 물량은 "측량 수로조사 및 지적에 관한 법률" 제86조에 규정된 면형 SOC(Social Overhead Capital) 사업이며, 여기에 포함되지 않은 선형 SOC 사업도 지적재조사사업과 연계를 통하여 효율성 향상을 기대할 수 있다. 선형 SOC 사업에서 용지경계측량이 이루어지면 설치된 경계말뚝을 이용하여 지역측지계에 의한 분할측량이 이루어지고, 사업이 완료된 후에 용지경계와 내부에 대한 지적재조사측량이 이루어진다. 본 연구에서 제시된 연계방안에 의하면 분할측량과 동시에 용지경계측량 성과를 이용하여 세계측지계에 의한 지적재조사측량 성과를 산출함으로써 중복작업을 배제할 수 있다. 본 연구를 통해 선형 SOC 사업과 지적재조사사업의 연계 방안을 제시하였으며, 이를 통해 년간 73,877필지, 4,078백만원의 효과가 발생할 것으로 예상되었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.577-584
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• 2000

Seismic refraction survey was peformed for 10 lines along NE-SW and NW-SE directions above Nampoong gallery at Makyo-ri, Dogye, Samcheok, Kangwon-do. 48 geophones were laid in line with the interval of 1m, and a 5Kg hammer was used as a source at 5 points for each line. Data processing was done using reciprocal time method, GRM, and traveltime tomography which utilizes wavefront expansion method for forward process and SIRT for inversion. The result shows that the first layer has its lower boundary between 3.49m and 8.88m. The P-wave velocity of the first and the second layer were estimated as 270 360m/s and 1550 1940m/s respectively. When the boundary of the first and second layer is smooth enough and the velocity difference is large enough, GRM has little advantage over reciprocal time method. The result of reciprocal method and traveltime tomography shows consistency. The northeast part of the boundary has syncline structure, which is similar to the topography above. This implies that the collapse of the cavities of Nampoong gallery result in the subsidence of the ground surface. The subsidence is in progress across the Youngdong railroad, therefore a proper reinforcement work is required.

• 디지털융복합연구
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• 제11권1호
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• pp.191-198
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• 2013

최근 스마트폰, 태블릿PC, 와이브로(WiBro), LTE 등 정보기술의 발전과 함께 스마트워크에 대한 관심이 증대되고 있다. 본 연구에서는 스마트워크를 도입함으로써 나타나는 업무 비업무 경계 모호성의 근본 문제를 경계 이론에 통해 이해하고자 하였다. 국내 K사의 재택근무와 스마트워크센터근무 이용자를 대상으로 경계 이론에서 제시하는 핵심 개념인 침투가능성, 경계 강도, 간섭 등을 포괄적으로 고려한 실증 연구를 수행하였다. 연구 결과를 통해 스마트워크 이용자는 업무와 비업무 영역 간의 비대칭성을 지각하고 있다는 사실을 확인하였다. 본 연구는 스마트워크와 관련된 향후 연구에서 업무와 비업무 영역 간 양방향성을 전제하여 경계 관리 전략을 고려할 필요성을 제시하고 있다.

• 전기전자학회논문지
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• 제25권4호
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• pp.650-663
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• 2021

Subsurface topology estimation is an important factor in the geophysical survey. Electrical impedance tomography is one of the popular methods used for subsurface imaging. The EIT inverse problem is highly nonlinear and ill-posed; therefore, reconstructed conductivity distribution suffers from low spatial resolution. The subsurface region can be approximated as piece-wise separate regions with constant conductivity in each region; therefore, the conductivity estimation problem is transformed to estimate the shape and location of the layer boundary interface. Each layer interface boundary is treated as an open boundary that is described using front points. The subsurface domain contains multi-layers with very complex configurations, and, in such situations, conventional methods such as the modified Newton Raphson method fail to provide the desired solution. Therefore, in this work, we have implemented a 7-layer artificial neural network (ANN) as an inverse problem algorithm to estimate the front points that describe the multi-layer interface boundaries. An ANN model consisting of input, output, and five fully connected hidden layers are trained for interlayer boundary reconstruction using training data that consists of pairs of voltage measurements of the subsurface domain with three-layer configuration and the corresponding front points of interface boundaries. The results from the proposed ANN model are compared with the gravitational search algorithm (GSA) for interlayer boundary estimation, and the results show that ANN is successful in estimating the layer boundaries with good accuracy.