• Journal of the Korean Geotechnical Society
• /
• v.19 no.6
• /
• pp.273-283
• /
• 2003

Fissured rock and soft ground always suggest, problems in the construction of the underground space. The stress release of the weak underground material by opening the underground space with a soft ground, fissures and joints can lead to the failure of the opening. Grouting of the weak rock and the soft ground, which is a process of injecting some bonding agents into the soft ground, is one of the measures to reinforce the soft ground and to prohibit the failure of the underground construction due to the stress release. The proper installation of the grouting is essential to ensuring the safety of the tunneling operation, so that the evaluation of the grouting performance is very significant. The general procedure of evaluating the grouting is coring the grouted section and measuring the compression strength of the core. However, sometimes when the grouted section is at the crown of the tunnel and the grouting is installed at a wide section, the coring is not good enough. This study is oriented to propose a new and a non-destructive procedure of evaluating the grouting performance. The proposed method is based on the wave propagation of elastic waves, and evaluates the shear stiffness of the ground and investigates the anomalies such as voids and cracks. The SASW ( Spectral-Analysis-of-Surface-Waves) method is one of the candidate s to make the inspection of the pouting performance, and is adopted in this study. The practical grouting activity was monitored by SASW method, and the proposed method was applied to the inspection of the grouting performance to check the verification of the proposed method.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2006.11a
• /
• pp.273-276
• /
• 2006

본 논문에서는 일반적인 수족관에서 물고기를 관찰하는데 있어서 관찰자가 빠르고 효율적으로 물고기에 대한 정보를 얻을 수 있는 방법을 제안하고자 한다. 여러 종의 물고기가 살고 있는 수족관 환경에서 처음 보는 관찰자과 쉽게 물고기에 대한 정보를 얻기는 힘들다. 이러한 제약을 효과적으로 개선하기 위하여 반 투영 거울을 사용하는 공간 증강 현실을 위한 영상출력 기법을 이용한다. 이때 피사체의 위치 정보를 얻기 위해 배경인 수족관영상과 피사체인 물고기영상을 분리한 후 물고기의 깊이 정보 값을 추출하기 위하여 호모그래피 행렬을 이용하고 보정된 이미지를 계산 한다. 실험결과 본 논문에서 제안한 방법을 통해 구축한 이 시스템으로 관찰자는 각각의 물고기들에 대한 정보를 반응형 Annotation으로 쉽게 얻을 수 있었다.

• Journal of Advanced Marine Engineering and Technology
• /
• v.37 no.5
• /
• pp.510-519
• /
• 2013

In this study, the spray characteristics of a pressure swirl atomizer classified into a liquid sheet-type swirl nozzle for Urea-SCR system were investigated experimentally with the variation of injection pressure. The length to diameter ratio ($l_o/d$) of the nozzle was 3.1, and the swirler was set inside the nozzle tip to give injecting fluid angular momentum. The injection duration of the nozzle was controlled by PWM (pulse width modulation) modes. The development processes of the spray were imaged by a 2-D PIV system, and the change of spray angle was measured. The atomization characteristics, including axial velocity and SMD, were measured using a 2-D PDA system with the injection pressures at room temperature and ambient pressure conditions. As the experimental results, the injection pressure had a significant impact on the spray structure showing a different shape around the spray leading edge, and the smaller SMD was observed with increasing injection pressures, which was similar to that of the previous work.

• Journal of the Institute of Convergence Signal Processing
• /
• v.19 no.3
• /
• pp.139-146
• /
• 2018

Underwater acoustic communication can be applied to various area such as scientific, commercial and military survey using Autonomous Underwater Vehicles and Unmanned Underwater Vehicles. Underwater communication is studying very actively by advanced country like United States. But differ from wireless communication in the air, underwater acoustic communication has some difficult problems, ISI(Inter Symbol Interference) due to multipath and limit of transmission bandwidth due to slow propagation of sound wave. In this paper, SC-FDE and OFDM transmission system for the cancellation of ISI in conjunction with underwater acoustic channel modeling are applied to the underwater simulation of communication. The performance of these methods in the simulation guide to possibility of adopting in underwater acoustic communication algorithm. For this purpose, we compare SER performance of SC-FDE with that of OFDM for modelled underwater channel. Underwater channel is generated by Bellhop model. Simulation results show above 5dB SNR gain at 10-3 SER. And it demonstrate SC-FDE is efficient method for underwater acoustic communication.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.25 no.4A
• /
• pp.558-565
• /
• 2000

While research of ATPG(automatic test pattern generation) for combinational circuits almost reaches a satisfiable level, one for sequential circuits still requires more research. In this paper, we propose new algorithm for sequential ATPG based on state information learning. By efficiently storing the information of the state searched during the process of test pattern generation and using the state information that has been already stored, test pattern generation becomes more efficient in time, fault coverage, and the number of test patterns. Through some experiments with ISCAS '89 benchmark circuits, the efficiency of the proposed method is shown.

• Journal of the Korean Society of Earth Science Education
• /
• v.10 no.2
• /
• pp.226-234
• /
• 2017

The purpose of this study is to investigate the effect of the application of storytelling on pre-service teachers of elementary school who take courses in 'earth's strata and rock' on science teaching concept and science teaching efficacy. The experiment was aimed at one class (32 students) enrolled in the 'earth's strata and rock' course at intensive course through 15 weeks from March to June. The experiment was taking lectures of "earth's strata and rock" for one semester, and the pre-service teachers of elementary school finished class demonstration with storytelling technique by group. The results and analysis of the study were analyzed by the corresponding sample test in before and after the group test. The conclusion of the study is as follows. First, the application of storytelling method on pre-service teachers of elementary school was effective in science concept. teaching efficacy. Second, the application of storytelling method on pre-service teachers of elementary school was effective in science teaching efficacy. Third, the application of storytelling method on pre-service teachers of elementary school responded positively.

• Journal of Broadcast Engineering
• /
• v.18 no.1
• /
• pp.10-20
• /
• 2013

Nowadays, video technology has been successfully improved creating tremendous results. As video technology improve, multimedia devices and demands from users are diversified. Therefore, a video codec used in these devices should support various displays with different resolutions. The technology to generate a higher resolution image from the associated low-resolution image is called interpolation. Interpolation is generally performed in either the spatial domain or the DCT domain. To use the advantages of both domains, we have proposed the new adaptive interpolation algorithm based on edge direction, which adaptively exploits the advantages of both domains. The experimental results demonstrate that our algorithm performs well in terms of PSNR and reduces the blocking artifacts.

• Proceedings of the Korean Information Science Society Conference
• /
• 2004.10b
• /
• pp.259-261
• /
• 2004

최근 이슈가 되고 있는 시스템 생물학(Systems Biology)은 생물학적인 이론과 컴퓨터의 계산적인 모델링 그리고 실험의 상호 의존적인 통합으로써 특징 지워진다. 그 중 컴퓨터의 계산적인 모델링에 대한 연구가 무엇보다 중요한 비중을 차지하고 있다. 하지만 계산적인 모델링에서 여러 자원을 통합하기 위한 공통의 기반 구조나 표준에 대한 연구는 미흡한 실정이다. 이러한 문제점을 해결하기 위해 KML 기반의 형식을 갖춘 SBML(Systems Biology Markup Language)이 시스템 생물학의 표준으로 개발되어 연구 중에 있다. 현재 시스템 생물학 분야에서 개발중인 시뮬레이션과 데이터 분석을 위한 다양한 응용 어플리케이션이 이미 SBML 문서를 지원하고 있다. 본 연구에서는 시스템 생물학 분야에서 SBML 표준에 대한 중요성을 인식하여, 객체지향 바이오 데이터베이스로부터 질의 결과를 SBML 문서로 변환하고, 반대로 외부의 SBML 문서를 객체지향 데이터베이스에 저장하는 변환기를 제안하며, 데이터를 검색하고 저장하는데 발생하는 중복이나 동의어 관계의 모호성을 줄이고 정확성을 높이기 위한 방안으로 온톨로지 기법을 적용한다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2014.11a
• /
• pp.1011-1013
• /
• 2014

2D/3D 입체영상의 변환을 위해 산업현장에서 아티스트가 경험적으로 양자화된 깊이 정보를 제작하고, 입력된 깊이 정보의 차이와 픽셀 간의 유사성을 이용하여 물체의 윤곽을 보존하는 한편, 실시간으로 평활화 과정을 수행하는 방법을 제안한다. 아티스트의 의도를 반영하기 위해 초기 입력한 깊이 정보를 바탕으로 적응적인 스무딩 파라미터를 할당함으로써 기존의 수작업을 반자동화하였다. 제안된 방법에서는 기존 방법의 평활화 단계에서 Domain Transformation 기법을 적용하고, 노이즈 제거 단계에서 양방향 필터를 적용하였다. 즉 산업 현장에서 문제점들을 해결하도록 알고리즘을 변형하여 기존 알고리즘의 성능을 개선하였다. 실험 결과는 제안된 방법이 기존의 제작 방법과 비교하여 적은 양자화 단계로 동일한 성능을 내는 것을 확인하였다.

• The Journal of the Acoustical Society of Korea
• /
• v.42 no.6
• /
• pp.519-528
• /
• 2023

The aim of this study was to enhance the flow rate and noise performance of a centrifugal pump in dishwashers by designing an optimized impeller shape through numerical and experimental investigations. To evaluate the performance of the target centrifugal pump, experiment was conducted using a pump performance tester and noise experiment was carried out in a semi-anechoic chamber with microphones and a reflecting wall behind the dishwasher. Through the use of advanced computational fluid dynamics techniques, numerical simulations were performed to analyze the flow and aeroacoustics performance of our target centrifugal pump impeller. To achieve this, numerical simulations were carried out using the Reynolds-Average Navier-Stokes equations and Ffowcs-Willliams and Hawkings equations as governing equations. In order to ensure the validity of numerical methods, a thorough comparison of numerical results with experimental results. After having confirmed the reliability of the current numerical method of this study, the optimization of the target centrifugal pump impeller was conducted. An improvement in flow rate was confirmed numerically, and a manufactured proto-type of the optimized model was used for experimental investigation. Furthermore, it was observed that by applying the fan law, we could effectively reduce noise levels without reducing the flow rate.