• Journal of the Earthquake Engineering Society of Korea
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• v.13 no.4
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• pp.67-76
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• 2009

Recently, the active interaction control (AIC) system was proposed as a semi-active control system. The AIC system consists of a primary structure and an auxiliary structure. The objective of the AIC system is to control the response of the primary structure through engagement and disengagement between the primary and auxiliary structures. Previous switching control algorithms have been shown to be effective in reducing the response of the primary structure. However, they have the main drawback of requiring an excessive engagement-disengagement frequency and high interaction force. In this paper, the regions in which the switching is activated and the regions in which the switching is deactivated are described separately, to effectively determine the engagement or the disengagement. The general relationship between the switching regions and the deactivated switching regions selected according to the engagement-disengagement conditions is described within the newly-developed comprehensive switching framework. The proposed engagement-disengagement conditions are designed within a comprehensive switching framework, to reduce engagement-disengagement frequency and interaction force. Furthermore, the effect of a control sampling period on the AIC system is explained in terms of the engagement-disengagement frequency. The effectiveness of the proposed algorithms and the effect of the control sampling period are considered for a single degree of freedom model under free vibration. It is observed that increasing the duration of stay by using a large control sampling period prevents the AIC system from activating the possible chance of switching. The proposed algorithms are shown to be effective, both in restricting ineffective switching and in reducing interaction force.

• Journal of Korean Home Economics Education Association
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• v.20 no.3
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• pp.215-230
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• 2008

Activity materials in textbook could facilitate students' oriented self-help learning. The purpose of this paper is to find out characteristics of activity materials in the housing area of middle school Technology and Home Economics and teacher's perception of them. The data were collected from 253 middle school teachers who had ever taught the housing unit in any of 6 textbooks. The results showed that the number of activity materials were differed by the characteristics of the materials such as type of materials, feature of non sentence materials, and type of activity, depend on authors as well as textbooks. In general, teachers interests in the materials were higher than those of students even the trends of the interests were the same. Adequacy of activity contents and related knowledge of teachers were higher than adequacy of level. Teachers thought time and extra search beyond class were barrier to full the interests of students. Further research is suggested to find out whether higher interests in the materials are related to the higher activating rate of them.

• The Journal of the Acoustical Society of Korea
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• v.16 no.3
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• pp.13-17
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• 1997

This paper investigates the influence of material properties of the acoustic damping layer in the low noise hydrophone designed in the previous paper. For increase of the insensitivity of the hydrophone to external noises, acoustic impedance and damping coefficients are selected and the effects of the selected material property on the hydrophone response to the external noises are simulated with finite element method (FEM). The results show that the damping coefficients are not influential to the structural vibration decoupling from the sensing element. On the other hand, the optimum acoustic impedance of compliant layer is estimated which is smaller than 1 Mrayl or larger than 4 Mrayl. However polymer materials, which are in general use for acoustic window and damping layers, is not appropriate for the compliant materials of this hydrophone. Therefore development of new composite materials, i.e. ceramic-polymer composite or metal-ceramic composites etc., is required for the development of effective self noise suppressing underwater hydrophones.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.4
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• pp.429-435
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• 2012

An abrasion due to continuous friction between a work roll and strip causes the mass of the work roll to be unbalanced in the rolling process. We developed a mathematical model for the rolling mill considering the unbalanced mass and verified the model experimentally. The work roll was approximated as a rigid rotor with eccentricity, and the effect of the unbalanced mass on chatter vibration was investigated. The joint forces computed by quasistatic analysis were applied to the work roll in the rolling mill. Transient responses were obtained, and frequency analysis was performed by solving equations of motion using a direct integration method. Horizontal vibrations were more strongly affected by eccentricity than vertical vibrations. In the horizontal direction, a small eccentricity of 1% of the work roll radius considerably increased the amplitude of the chatter frequency.

• Annual Conference on Human and Language Technology
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• 2023.10a
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• pp.648-653
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• 2023

관계 추출 태스크는 주어진 텍스트로부터 두 개체 간의 적절한 관계를 추론하는 작업이며, 지식 베이스 구축 및 질의응답과 같은 응용 태스크의 기반이 된다. 최근 자연어처리 분야 전반에서 생성형 거대 언어모델의 내재 지식을 활용하여 뛰어난 성능을 성취하면서, 대표적인 정보 추출 태스크인 관계 추출에서 역시 이를 적극적으로 활용 가능한 방안에 대한 탐구가 필요하다. 특히, 실 세계의 추론 환경과의 유사성에서 기인하는 저자원 특히, 제로샷 환경에서의 관계 추출 연구의 중요성에 기반하여, 효과적인 프롬프팅 기법의 적용이 유의미함을 많은 기존 연구에서 증명해왔다. 따라서, 본 연구는 한국어 관계 추출 분야에서 거대 언어모델에 다각적인 프롬프팅 기법을 활용하여 제로샷 환경에서의 추론에 관한 비교 연구를 진행함으로써, 추후 한국어 관계 추출을 위한 최적의 거대 언어모델 프롬프팅 기법 심화 연구의 기반을 제공하고자 한다. 특히, 상식 추론 등의 도전적인 타 태스크에서 큰 성능 개선을 보인 사고의 연쇄(Chain-of-Thought) 및 자가 개선(Self-Refine)을 포함한 세 가지 프롬프팅 기법을 한국어 관계 추출에 도입하여 양적/질적으로 비교 분석을 제공한다. 실험 결과에 따르면, 사고의 연쇄 및 자가 개선 기법 보다 일반적인 태스크 지시 등이 포함된 프롬프팅이 정량적으로 가장 좋은 제로샷 성능을 보인다. 그러나, 이는 두 방법의 한계를 지적하는 것이 아닌, 한국어 관계 추출 태스크에의 최적화의 필요성을 암시한다고 해석 가능하며, 추후 이러한 방법론들을 발전시키는 여러 실험적 연구에 의해 개선될 것으로 판단된다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.1
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• pp.97-105
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• 1992

The purpose of this study is to provide the cause and countermeasure for track problems in the high speed railways due to the irregularly increasing dynamic wheel loads running over the speed range of 300 km/h. It has long been recognised that the track problems encountered on high speed railways are associated mainly with vertical dynamic loads which are related to the unsprung mass of vehicles and track irregularities. In addition to these parameters for the estimation of the dynamic wheel load variation, however, the dynamic characteristics of track structures are discussed in this paper with reference to mathematical modelling of the tracks and vehicle. From the results of the more detailed analyses, the effects of track stiffness and damping characteristics are considered to be significant for reducing the dynamic wheel loads. To make this point clear and appraise the overall performance of the track components, the theoretical analysis on the dynamic behavior of the tracks and wheel set impact tests on several track structures are performed. The experimental results from different track components are compared with each other. The track stiffness and damping characteristics are also presented quantatively.

• Journal of the Korean Geotechnical Society
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• v.39 no.3
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• pp.5-16
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• 2023

The effect of raft flexibility on piled raft foundations in sandy soil was investigated using a numerical analysis and an analytical study. The investigation's emphasis was the load sharing between piles and raft following the raft rigidity (K_R), end-bearing conditions. The case of individual piles and subsequently the response of groups of piles was analyzed using a 3D FEM. This study shows that the α_pr, load-sharing ratio of piled raft foundations, decreases as the vertical loading increases and as the K_R decreases. This tendency is more obvious when using friction piles compared to using end-bearing piles. The effect of raft rigidity is found to be more significant for the axial force distribution - each pile within the foundations has almost similar axial forces of the pile head with a flexible raft; however, each pile has different values with rigid rafts, especially with the end-bearing piles. The axial force of the pile base with floating piles shows similar point-bearing resistance for all the piles; however, it shows different values with end-bearing piles. The differential settlement ratio of rafts showed a larger value with lower K_R.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.4
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• pp.633-642
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• 2021

Growing demand for electricity, when combined with the need to limit carbon emissions, drives a huge increase in renewable energy industry. In the electric power system, electricity supply always needs to be balanced with electricity demand and network losses to maintain safe, dependable, and stable system operation. There are three broad challenges when it comes to a power system with a high penetration of renewable energy: transient stability, small signal stability, and frequency stability. Transient stability analyze the system response to disturbances such as the loss of generation, line-switching operations, faults, and sudden load changes in the first several seconds following the disturbance. Small signal stability refers to the system's ability to maintain synchronization between generators and steady voltages when it is subjected to small perturbations such as incremental changes in system load. Frequency stability refers to the ability of a power system to maintain steady frequency following a severe system upset resulting in significant imbalance between generation and load. In this paper, we discusses these stability using system simulation by renewable energy deployment plan, and also analyses the influence of the renewable energy sources to the grid stability.

• Journal of dental hygiene science
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• v.11 no.2
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• pp.129-134
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• 2011

The purpose of this study was to examine the professors, who teach the dental hygiene program in Korea, their Awareness on authors determined among research ethics. Three hundred and six full time professors and four hundred and eighty four part time professors in seventy eight universities all around Korea were surveyed. The following are the results that the collected data was carried out statistical analysis by using SPSS 12.0 program. The results was as followed. 1. The present study's author makers, 95 respondents (55.6%) experienced advising professor and 67 respondents (39.2%) experienced personally. 2. As recognition about range and order decision of the authors, they expressed the biggest recognition that person who did the interpretation of the results or gave important information doesn't always become the first author of the article($2.81{\pm}.485$). 3. Between general characteristics and authorship recognition level, they were statistically significantly different with number of articles published as the first author(p<0.05). 4. Regarding the correlation between students who helped with collection of data and references also have the right to be the author of the research article and Person who did the rough draft translation also has the right to be the co-author of the research article had a statistically significant correlation of .433 which was the highest correlation factor (p<0.01). Conclusions, rules and regulations on research ethic should be more publicized through educational institutions.

• Design Convergence Study
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• v.15 no.4
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• pp.45-58
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• 2016

The purpose of this study is to investigate the most effective emoticon type in on-line communication context through analysis decoding(by their interpretation, empathy, reaction) of receiver about emotional message included the various emoticon types. Message types were all 5 - only text message and messages included texticon, graphicon, anicon, and photocon that reflected the transitional process of emoticon. Survey questionnaire that included various emotional situations was developed and utilized to undergraduate students to analyze the differences in their gender and majors. Results are as follow. First, the graphicon, anicon and photocon messages had higher effectiveness than others in the pleasure while the text only message had the highest effectiveness of them in the displeasure. Second, female students responded that the graphicon, anicon and photocon messages were more effective while male students responded that text only message was. Third, between Arts/Physical and Science/Engineering majors had significant differences in some message types, and especially Science/Engineering majors showed higher average than other majors in all of the emoticon types. These results can provide the information to design messages by the emotional situation of sender and gender and major of receiver.