• The Journal of Engineering Geology
• /
• v.25 no.2
• /
• pp.201-213
• /
• 2015

Site effects resulting in the amplification of earthquake ground motion are strongly influenced not only by the subsurface soil conditions and structure, but also by the surface topography. Yet, over the last several decades, most studies of site-specific seismic responses in Korea have focused primarily on the seismic amplification associated with geologic and soil conditions. For example, the effects of local geology are now well established and have been incorporated into current Korean seismic design codes, whereas topographic effects have not been considered. To help address this shortcoming, two-dimensional (2D) seismic site response analyses, using finite element (FE) ground modeling with three different slope angles, were performed in order to assess the site effects of surface topography. We then compared our results, specifically peak ground acceleration (PGA) and acceleration response spectrum, to those of one-dimensional (1D) FE model analyses conducted alongside our study. Throughout much of the upper slope region, PGAs and spectral accelerations are larger in the 2D analyses than in the 1D analyses as a result of the topographic effect.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.20 no.6
• /
• pp.278-282
• /
• 2010

The doping effect of thulium on electrical properties and degradation behavior in barium titanate ceramics ($BaTiO_3$) was investigated in terms of generations of core-shell structure and micro-chemical changes through highly accelerated degradation test. The dielectric specimens of pellet type and multi-layered sheets were prepared by using $BaTiO_3$ with undoped and doped with 1 mol% $Tm_2O_3$. The $BaTiO_3$ ceramics doped with 1 mol% $Tm_2O_3$ had 40% higher dielectric constant (${\varepsilon}$ = 2700) than that of the undoped $BaTiO_3$ specimen at curie temperature and met X7R specification. According to the result of highly accelerated degradation test conducted at $150^{\circ}C$, 70 V, and 24 hr, the oxygen diffusion was declined in dielectrics doped with 1 mol% $Tm_2O_3$. The $Tm^{3+}$ ion substituted selectively Ba site and Ti site and contributed to the generation of the core-shell structure. Oxygen vacancies occurred by substitution for Ti site could reduce excess oxygen that reacted to the Ni electrode.

• Korean Journal of Construction Engineering and Management
• /
• v.20 no.4
• /
• pp.56-68
• /
• 2019

An optimal selection of form-work is very important in the construction project in terms of construction cost and duration management. Also, it substantially affects the quality of the structure and the finishing work. However, in South Korea, the decision making on the selection of form-work has been based on the experience and intuition of construction practitioners not on the objective data or rational decision-making system. In order to solve the problem, several types of research on the selection of form-work has been processed. However, they did not consider the construction site condition, which is one of the most important factors for the selection of form-work. Thus, the objective of this study is developing the objective decision supporting system considering the site condition. This study provides the quantitative decision support model for optimal form-work based on construction site type. It is expected that the decision support model will help the practitioners decide optimal form-work based on the objective data. It will ameliorate the existing decision making process using experience and intuition. In addition, because the model considers site-conditions, it will provide more accurate and appropriate decision on the selection of an optimal form-work.

• The Journal of Engineering Geology
• /
• v.33 no.4
• /
• pp.599-609
• /
• 2023

In the seismic retrofitting of harbor breakwaters in Korea, the recovery rate is often uncertain due to site conditions and site conditions, and problems continue to arise. Therefore, in this study, we analyzed the recovery rate and compressive strength of the improved material through drilling survey by grouting confirmation method after applying low-fluidity mortar injection method, and furthermore, we checked the elastic modulus by downhole test and tomography to confirm the reinforcement effect of soft ground after ground improvement. The experimental results showed that the average shear wave velocity of the ground increased from 229 m/s to 288 m/s in BH-1 and BH-3 boreholes to a depth of 28.0 m, and the average shear wave velocity of the ground to a depth of 30.0 m tended to increase from 224 m/s to 282 m/s in the downhole test. This is believed to be a result of the increased stiffness of the ground after reinforcement. The results of the tomographic survey showed that the Vs of the soft ground of the sample at Site 1 increased from 113 m/s to 214 m/s, and the Vs of the sample at Site 2 increased from 120 m/s to 224 m/s. This shows that the stiffness of the ground after seismic reinforcement is reinforced with hard soil, as the Vs value satisfies 180 m/s to 360 m/s in the classification of rock quality according to shear wave velocity.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2008.11a
• /
• pp.21-26
• /
• 2008

We investigate the various factors such as earthquake, fire, flood and deterioration factors such as carbonation, salt attack, freezing thawing, alkali-aggregate reaction effects on the school facilities. As the consequence of this study we can see that there are very relative relation between deterioration factors and disaster factors. It is the aim of this study to investigate the site analysis damaged by disaster and deterioration factors of school facilities.

• Annual Conference of KIPS
• /
• 2001.10b
• /
• pp.1569-1572
• /
• 2001

현재 무선 환경에서의 인터넷 사용에 대한 수요는 폭발적으로 증가하고 있으며 이에 따라 각종 무선 휴대 장치가 빠른 속도로 보급되고 있다. 이와 동시에 WAP 포럼에서 제정한 WML(Wireless Markup Language)을 사용하여 저작된 무선 컨텐츠의 양적, 질적 성장 또한 이뤄지고 있으며, 대형 무선 컨텐츠 제공업체들도 속속 등장하고 있는 추세이다. 따라서 본 논문에서는 WML을 사용하여 대형 무선 컨텐츠를 저작한 때 요구되어지는 기능인 다수 개발자의 동시 저작 기능과 WML 문서내의 링크 및 실시간 Push 서비스, CGI, PERL 스크립트, voice Mail, Fax, E-Mail 템플릿 자동생성 등을 지원하는 WML 저작도구의 설계 및 구현에 대하여 논한다.

• Korean Journal of Microbiology
• /
• v.24 no.4
• /
• pp.406-410
• /
• 1986

The isolation and charateriation of a type II restriction endonuclease from Xanthomonas citri IFO 3835 were described. This enzyme (Xci I endonuclease) is an isoschizomer of Sal I endonuclease recognizing 5'-GTCGAC-3' and cleaving at the site indicated by the arrow. Unlike Sal I endonuclease, Xci I endonuclease requries a NaCl concentration of 50mM for its maximum activity.

• Proceedings of the IEEK Conference
• /
• 2001.06a
• /
• pp.141-144
• /
• 2001

This paper has been studied a implementation of HTML Filter with structured decks. In wireless environment, conventional HTML Filter converts HTML document to WML by once. However, it is more efficient to access a WEB site by transmitting the minimal capacity of core data in WAP environment. Therefore this paper suggests new HTML Filter that automatically analyze the contents of HTML WEB and transmits it by selecting the one of many Decks that have the structured architecture. Also the protocol between wireless terminal and WAP Gateway is considered. Finally, We test the proposed HTML Filter with structured Decks for some particular web site.

• Journal of Construction Engineering and Project Management
• /
• v.5 no.1
• /
• pp.40-46
• /
• 2015

This study presents the results of our analysis and recommendations for process and productivity improvements. The project studied consists of a 5-story research building, with a structure of steel frames supporting concrete slabs. The observations focused on the analysis of the overall erection and framing process. The methods used for the analysis consisted in intensive visits on site, where construction processes were observed in term of resources, activities, durations, materials' handling procedures, and technology used. Back to the office, authors used the information captured to model the different trades' activities, using work sampling and 5-minute rating technique. The work sampling provides insight into the activity, hence allowing for process improvements. The productivity of various trades is strongly dependent on the organization of the work process and work site conditions. Improving the productivity of the entire project or company is not possible until everyone is committed to improvement.

• International conference on construction engineering and project management
• /
• 2022.06a
• /
• pp.808-813
• /
• 2022

This study presents the problems of data imbalance, varying difficulties across target objects, and small objects in construction object segmentation for far-field monitoring and utilize compound loss functions to address it. Construction site scenes of assembling scaffolds were analyzed to test the effectiveness of compound loss functions for five construction object classes---workers, hardhats, harnesses, straps, hooks. The challenging problem was mitigated by employing a focal and Jaccard loss terms in the original loss function of LinkNet segmentation model. The findings indicates the importance of the loss function design for model performance on construction site scenes for far-field monitoring.