• Proceedings of the KSR Conference
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• 2009.05a
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• pp.15-19
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• 2009

Due to the Japan's Kobe earthquake in 1995, a cut-and-cover tunnel, which is one of subway facilities, collapsed unexpectedly. As a result, also in Korea, seismic performance needs to be secured for the cut-and-cover tunnel and currently, the subway seismic design standard is based on the seismic performance. However, there is no standard for the damage level or stability level of a member for securing the seismic performance, and the definition of multi-level seismic performance is not sufficient. By contrast to this situation, in the Japan's evaluation method of seismic performance, design earthquake ground motion having reflected there into the subway driving stability is clearly defined and the seismic performance required for structures is classified in detail. This study analyzes the Japan's systematic evaluation method of seismic performance for cut-and-cover tunnels of subway.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.445-452
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• 2011

The schedule hierarchy in construction project is generally composed of three levels. The highest level is a milestone schedule and represented by Bar Chart format. The middle level is an integrated project schedule (IPS) and represented by CPM (Critical Path Method) format. The lowest level is a detail working schedule and usually represented by Bar Chart. The traditional scheduling techniques such as ADM (Arrow Diagramming Method) or PDM (Precedence Diagramming Method) cannot represent all kinds of schedule within schedule hierarchy as identical schedule format. However, the BDM (Beeline Diagramming Method) technique can represent all kinds of schedule within schedule hierarchy as identical CPM format. This paper describes the basic concept, principle, interpretation methods, and schedule computation methods of the BDM as a new networking technique that can represent all kinds of overlapping relationships between activities, and then presents an example of representing three level's schedules within schedule hierarchy by the BDM technique.

• Applied Science and Convergence Technology
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• v.25 no.5
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• pp.98-102
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• 2016

The level set method has recently become popular in the simulation of semiconductor processes such as etching, deposition and photolithography, as it is a highly robust and accurate computational technique for tracking moving interfaces. In this research, full three-dimensional level set simulation has been developed for the investigation of focused ion beam processing. Especially, focused ion beam induced nanodot formation was investigated with the consideration of three-dimensional distribution of redeposition particles which were obtained by Monte-Carlo simulation. Experimental validations were carried out with the nanodots that were fabricated using focused $Ga^+$ beams on Silicon substrate. Detailed description of level set simulation and characteristics of nanodot formation will be discussed in detail as well as surface propagation under focused ion beam bombardment.

• The Journal of the Korea Contents Association
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• v.21 no.8
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• pp.258-270
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• 2021

This study aimed to investigate the effects of the virtual reality simulation for malocclusion examination for dental education. A 4-step modeling procedure was applied to develop a tooth model with a realistic level in order to be held and observed in detail. Eighty-six participants used HMDs to examine the developed virtual dental simulation to identify their perception according to expertise levels. The independent variable, expertise group, included three levels: 29 juniors, 29 seniors, and 28 dentists, respectively. The dependent variables, that were task-load and usability, were measured through two cases. Results showed that the junior group perceived a higher level of mental demands and embarrassment than the dentist group. It indicated that the perceived task load varies according to the expertise levels in the simulation task. However, the senior group perceived a higher level of ease of use than the dentist group. This study presented the implications for the development of virtual reality simulation in detail.

• Asia pacific journal of information systems
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• v.29 no.4
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• pp.771-788
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• 2019

Deep learning techniques such as Convolutional Neural Networks (CNNs) and Recurrent Neural Networks (RNNs) show superior performance in text classification than traditional approaches such as Support Vector Machines (SVMs) and Naïve Bayesian approaches. When using CNNs for text classification tasks, word embedding or character embedding is a step to transform words or characters to fixed size vectors before feeding them into convolutional layers. In this paper, we propose a parallel word-level and character-level embedding approach in CNNs for text classification. The proposed approach can capture word-level and character-level patterns concurrently in CNNs. To show the usefulness of proposed approach, we perform experiments with two English and three Korean text datasets. The experimental results show that character-level embedding works better in Korean and word-level embedding performs well in English. Also the experimental results reveal that the proposed approach provides better performance than traditional CNNs with word-level embedding or character-level embedding in both Korean and English documents. From more detail investigation, we find that the proposed approach tends to perform better when there is relatively small amount of data comparing to the traditional embedding approaches.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.162-163
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• 2013

A temporary work are lifting equipment that tower crane or lift, and temporary architectures that office building and storage in construction site. And it is main construction work that built and used temporarily like to a scaffolding, a walk plate, and a formwork. This study is to adjust breakdown structure of temporary work to introduce technical tendency. With a site manager, it is collected a detailed statement and compared. As a result to break down a tendency that temporary equipment, additional function, and direct work of temporary technique, first, existing detail technical indexes that group I, group J, group K, and group L are classified. Second, due to set up and manage to main agents in case of existing detail technical indexes that B1, B2, it is not wrong to classify. But, it is somewhat different, and therefore adjust it to same level. Finally, as a technical tendency that temporary equipment, additional function, and direct work of temporary technique, it is adjusted the others.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.473-474
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• 2011

Image quantization 기술은 영역 평탄화 기술중 하나로서 NPR과 같은 컴퓨터 그래픽스 분야에서 널리 쓰이고 있는 기술 중 하나이다. 하지만 기존의 image quantization은 중요부분을 고려하지 않기 때문에 detail한 칼라 정보를 가지는 주요 영역이 있는 경우에는 그 결과가 좋지 못한 단점을 가지고 있다. 본 논문에서는 이러한 단점을 극복하기 위해, Sailency map을 이용해 영상의 주요 영역을 고려한 image Flattening 기법을 제안한다. 제안한 방법은 검출된 주요 영역을 좀 더 세분화해서 표현하므로 기존의 방법과 비교해 좀 더 좋은 결과를 보여준다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.835-841
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• 2005

실시간 가시화/시각화(Visualization)을 위한 지형 가시화 분야에서의 렌더링 속도 향상은 사용자의 현실감에 있어 중요한 역할을 한다. 본 연구는 Height Field 데이터를 사용한 블록 단위 지형 렌더링 방법에서 이전 프레임 정보를 사용하여 지형 가시화 속도를 향상시키는 방법을 제안한다. Height Field로 표현된 지형을 실시간에 효과적으로 렌더링 할 수 있는 방법으로CLOD(Continuous leveI Of Detail)가 있으며 대표적인 방법으로 Multiresolution TIN(Triangle Irregular Network)과 Regular Grid Method에 기반한 방법들이 있다. 대개의 경우, 지형 데이터는 매우 방대한 크기를 가지고 있어서 실시간으로 렌더링 하는 것이 불가능할 경우가 많다. 따라서 실시간 지형렌더링 에서는 LOD(Level of Detail)관리와 뷰 프러스텀 컬링이 실시간 렌더링 속도 향상을 위한 핵심 사항이 된다. 본 연구에서는 PC 기반에서 효과적으로 지형을 표현하기 위해 기존 Regular Grid Method에 기반한 방법의 가시영역 추출(View Frustum Culling)을 수정하여 실시간 지형 렌더링의 가시 영역 추출(View Frustum Culling)시 기존의 쿼드트리 방식과 함께 이전 프레임에서 블록 단위로 저장된 컬링 정보를 혼용하여 속도를 향상시키는 방법을 상세히 기술 한다.

• Journal of Korean Society of Rural Planning
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• v.14 no.3
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• pp.63-73
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• 2008

The purpose of this study is to analyze the determinants of the digital divide at individual level and regional level in Korea, considering interaction between individual and the regional variables. Following results are obtained. First, individual level digital devide in the 16 different regions has been found in terms of Internet use, implying the needs for further analysis on impact of the regional factor in individual Internet use. Second, the result finds the impact of level-l individual variables, "gender, age, education, income and jobs" on digital divide, significantly at level 10% level. Third, the regional variables influencing the individual digital divide were not found at state level. However, regional factors might affect digital devide at county level. Study suggest some plans to reduce digital divide. First, the digital devide at individual level should be remedied by focusing on neglected class of people. Second, we need to approach the digital divide by analyzing in more detail, reflecting interactions of the regional variables and individual variables. Third, we should come up with a policy for mending the digital divide at regional level.

• Journal of Power Electronics
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• v.13 no.1
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• pp.86-93
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• 2013

A half-cycle-waveform inversion based three reference modulations seven-level SPWM (TRM-SPWM) scheme with one carrier is proposed in this paper. To keep the same comparison logics for the modulations and carrier during the negative half cycle and the positive one for the modulations, in the negative half cycle of the modulations, the DC offsets related to the amplitude of the carrier are set on the three modulations, respectively. The seven-level SPWM waveform with dead time thereby is implemented with only one Digital Signal Processor (DSP) without any other attached logic circuit. The basis principle of the proposed TRM-SPWM is analyzed in detail, and the frequency spectrums of the conventional and the proposed schemes are derived and compared with each other through simulation. The DSP based implementation is presented and detailed experimental waveforms verify the accuracy and feasibility of the proposed TRM-SPWM scheme.