• Journal of the Korea Concrete Institute
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• v.17 no.6 s.90
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• pp.983-992
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• 2005

The shear failure modes of fiber reinforced polymer(FRP) strengthened concrete beams are quite different to those of the beams strengthened with steel stirrups. When the beams are strengthened with larger amount of FRP composites, the beams normally fail in shear due to concrete crushing before the FRP reaches its rupture strain. In order to predict the shear strength of such beams, the actual rupture strain must be known. The equations previously reported in the technical literature adopt an effective reduction factor for the rupture strain. These equations may not be applicable to FRP strengthened RC beams that are beyond the experimental application limits, because most of these equations are empirical in nature. This paper presents the results of an analytical study on the performance of reinforced concrete beams externally wrapped with FRP composites and internally reinforced with conventional steel stirrups.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.303-310
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• 2002

Overbreak occurred inevitably in a tunnel excavation, Is the main factor for increasing cost and time in tunnel projects. Furthermore the damage to the remained rock mass related to the overbreak can give rise to a serious safety problem in tunnels. As a rule of thumb, causes for the overbreak are inaccuracy in drilling, the wrong design of blasting and selection of explosives, and heterogeneity in rock mass. Specially, the geological features of the rock mass around periphery of an excavation are very important factors, so a lot of researches have been conducted to describe these phenomena. But the quantitative geological classification of the rock mass for the overbreak and the method for decreasing the amount of the overbreak have not been established. Besides, the technical improvement of the charge method is requested as explosives for the smooth blasting have not functioned efficiently. In this study, the working face around periphery of an excavation has been continuously sectionalized to 5∼6 parts, and the new Blastability Index for the overbreak based on 6 factors of RMD(Rock Mass Description), UCS(Uniaxial Compressive Strength) JPS(Joint Plane Spacing), JPO(Joint Plane Orientation), JPA(Joint Plane Aperture) and FM(Filling Material) is proposed to classify sections of the working face. On the basis of this classification, the distance between contour holes and the charging density are determined to minimize the overbreak. For controlling the charging density and improving the function of explosives, the New Deck Charge(N.D.C) method utilizing the deck charge method and detonation transmission in hole has been developed.

• Journal of the Korean housing association
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• v.19 no.6
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• pp.145-155
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• 2008

This study examined the actual use and users‘ satisfaction with the university dormitories in Gwangju and Chonnam and analyse the related variables that affect on them. Self-administered questionnaires were provided to 200 university students from Gwangju and the Chonnam area. The collected data was used to conduct comparative and descriptive statistical analysis: T-test Below are the study findings. Female students express more satisfaction with community affinity than male students in the satisfaction about socio-psychological environment. Students residing in the rooms for 2 persons express more satisfaction with the division of private space with common space, study appropriateness etc. than those residing in the rooms for 4 persons. Students residing in the cluster-type rooms express more satisfaction with the division of private space with common spaces study appropriateness and relationship with other students in other rooms etc. In relation to the room environment, female students express less dissatisfaction with the noise than male students. Students residing in the rooms for 2 persons express more satisfaction with the room size, interior temperature pleasantness, brightness etc. than those residing the in rooms for 4 persons. Students residing in the cluster-type rooms express more satisfaction with the bed size, the condition of interior finishing, interior temperature pleasantness, brightness and interior air pleasantness etc. than those residing in unit-rooms. In relation to common using environment, male students express more satisfaction with the library than female students. And students residing in the rooms for 4 persons and those residing in the cluster-type rooms express more satisfaction with lounge than those residing in the rooms for 2 persons and those residing in the unit-rooms. Organizing the university domitory planning according to the students' demands, based on this study, the change to general function of domitory in sleeping, studying, leisure activity and culture acitivity is needed. Interior environment technical factor of interior air pleasantness and noise should be improved.

• Journal of the Korean Institute of Rural Architecture
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• v.2 no.2
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• pp.23-34
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• 2000

Many primary schools that have been an important role in the community at the same time local important facility not only local area but also all area in Korea have shown a situation for closing and into grating a school because of a social and political measure. The education policy for man power training and closing policy for small scale school not more than 100 students can't role in the rural development policy, coming farming and fishing villages. The reasons for thinking some application paradigm and closing schools have been important role in the point of education and culture parts. Of course, the application paradigm for closing school facility will get accomplished for a mood of local residents and a point of cultural deference, not keeping up unconditionally for closing a school. For accomplishing versatile purposes, initiative role of the organs of local education is very important. The organs of local education have an application paradigm that closing schools are the facilities for local organs of education will plan some specific facility to be matched for local special quality and connection quality of surrounding facility and environment. Before an application paradigm of closing school, it is very important that a fundamental factor for negligence the facility will be solved. Eventually, the organs of education have a plan for technical study of this paradigm and consider keeping and mending of closing facility, rent the facility for payment or not they want, and confer money problem not an unconditional scale.

• BMB Reports
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• v.53 no.6
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• pp.299-310
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• 2020

Chronic liver disease progresses through several stages, fatty liver, steatohepatitis, cirrhosis, and eventually, it leads to hepatocellular carcinoma (HCC) over a long period of time. Since a large proportion of patients with HCC are accompanied by cirrhosis, it is considered to be an important factor in the diagnosis of liver cancer. This is because cirrhosis leads to an irreversible harmful effect, but the early stages of chronic liver disease could be reversed to a healthy state. Therefore, the discovery of biomarkers that could identify the early stages of chronic liver disease is important to prevent serious liver damage. Biomarker discovery at liver cancer and cirrhosis has enhanced the development of sequencing technology. Next generation sequencing (NGS) is one of the representative technical innovations in the biological field in the recent decades and it is the most important thing to design for research on what type of sequencing methods are suitable and how to handle the analysis steps for data integration. In this review, we comprehensively summarized NGS techniques for identifying genome, transcriptome, DNA methylome and 3D/4D chromatin structure, and introduced framework of processing data set and integrating multi-omics data for uncovering biomarkers.

• Earthquakes and Structures
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• v.9 no.3
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• pp.481-501
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• 2015

Current design codes and technical recommendations often provide rough indications on how to assess effective stiffness of Reinforced Concrete (R/C) frames subjected to seismic loads, which is a key factor when a linear analysis is performed. The Italian design code (NTC-2008), Eurocode 8 and ACI 318 do not take into account all the structural parameters affecting the effective stiffness and this may not be on the safe side when second-order $P-{\Delta}$ effects may occur. This paper presents a study on the factors influencing the effective stiffness of R/C beams, columns and walls under seismic forces. Five different approaches are adopted and analyzed in order to evaluate the effective stiffness of R/C members, in accordance with the scientific literature and the international design codes. Furthermore, the paper discusses the outcomes of a parametric analysis performed on an actual R/C building and analyses the main variables, namely reinforcement ratio, axial load ratio, concrete compressive strength, and type of shallow beams. The second-order effects are investigated and the resulting displacements related to the Damage Limit State (DLS) under seismic loads are discussed. Although the effective stiffness increases with steel ratio, the analytical results show that the limit of 50% of the initial stiffness turns out to be the upper bound for small values of axial-load ratio, rather than a lower bound as indicated by both Italian NTC-2008 and EC8. As a result, in some cases the current Italian and European provisions tend to underestimate second-order $P-{\Delta}$ effects, when the DLS is investigated under seismic loading.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.39 no.2
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• pp.44-50
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• 2002

Conventional acoustic echo cancelers using ES(Exponentially weighted Stepsize) algorithm have simple operational configuration and fast convergence speed batter then NLMS algorithm, but they are very weak in external noise because ES algorithm updates filter taps using an average energy reduction rate of room impulse response in specific acoustical condition. So, a new configuration of acoustic echo canceler with stepsize generator and selector is proposed in this thesis. The proposed stepsize generator and selector improve conventional acoustic echo canceler's weakness in external noise and improve the system robustness. The stepsize generator generates additional stepsize value using moving averager, which is the residual noise energy of error signal multiplied by constant ${\gamma}$. The stepsize selector selects the stepsize value that has better performance in an acoustic echo canceler using a coefficient decision factor ${\Delta}_{differ}$ The simulation results show that the proposed algorithm reduces residual error by 5[dB] to 10[dB], improves misadjustment regardless of external noise's SNR. 

• Journal of Korean Association for Spatial Structures
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• v.7 no.1 s.23
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• pp.71-78
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• 2007

Stainless steel is very famous for using of industrials structure and joint elements. Stainless steel wire drawing is one of the most ancient crafts. But there's not any standard size of tapered die during tile drawing. This paper was studied die angle and dimension of whole die by using AFDEX drawing simulator. Stress, metal flow and strain rate was analyzed by AFDEX tools during the wire drawing. So optimum data of during dies was taken from them. Simulation data was correspond with experimental data. The results of the optimum dies are shown that (1) Reduction angle is $13.8^{\circ}$ (2) Bark relief angle is $20^{\circ}$ (3) Bearing length is 0.7975mm (4) Bearing dia is 0.2393mm The research of the optimum result when the make dies is connected an enterprise. After researching, I hope that indirection effect creation make development situation of the manufactural technical, practical application of the other die size by the detail data, utility factor and economical efficiency.

• Nuclear Engineering and Technology
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• v.45 no.2
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• pp.125-140
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• 2013

This paper aims to give an overview of the methods to inherently prevent human errors and to effectively mitigate the consequences of such errors by securing defense-in-depth during plant management through the advanced man-machine interface system (MMIS). It is needless to stress the significance of human error reduction during an accident in nuclear power plants (NPPs). Unexpected shutdowns caused by human errors not only threaten nuclear safety but also make public acceptance of nuclear power extremely lower. We have to recognize there must be the possibility of human errors occurring since humans are not essentially perfect particularly under stressful conditions. However, we have the opportunity to improve such a situation through advanced information and communication technologies on the basis of lessons learned from our experiences. As important lessons, authors explained key issues associated with automation, man-machine interface, operator support systems, and procedures. Upon this investigation, we outlined the concept and technical factors to develop advanced automation, operation and maintenance support systems, and computer-based procedures using wired/wireless technology. It should be noted that the ultimate responsibility of nuclear safety obviously belongs to humans not to machines. Therefore, safety culture including education and training, which is a kind of organizational factor, should be emphasized as well. In regard to safety culture for human error reduction, several issues that we are facing these days were described. We expect the ideas of the advanced MMIS proposed in this paper to lead in the future direction of related researches and finally supplement the safety of NPPs.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.4
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• pp.175-184
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• 2017

With the improvement of living standards, the ventilation for the mitigation of indoor or outdoor air-pollution problems has recently attracted a lot of attention. Consequently, the ventilation for the supply of outdoor fresh air into a room is treated as an important building-design factor. The ventilation is generally divided into the forced and natural types; here, the former can control the ventilation rate by using mechanical devices, but it has the disadvantages of the equipment costs, maintenance costs, and noise generation, while the latter is applied to most workshops due to the absence of noise and the low installation and maintenance costs. In this experimental study, the ventilation performance of a typical rotating-type natural ventilator, which is called a "wind turbine," was investigated with the outdoor-wind velocity and the indoor/outdoor-temperature difference. From the experiment results, it was confirmed that the temperature difference of $10^{\circ}C$ corresponds to the ventilation driving force with an outdoor-wind velocity of 1.0 m/s. Additionally, the intake-opening area of a building also exerts a great effect on the ventilation rates.