• Title/Summary/Keyword: Concrete Core

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A Study on the Main Issue and Its Solution Explored through Mediation Cases - Focused on the Cases of Busan National Labor Relations Commission - (조정사건을 통해 살펴본 주요 쟁점사항과 해결방안에 대한 연구 - 부산지방노동위원회의 사례를 중심으로 -)

  • Song, Kyung-Soo;Kim, Yong-Ho
    • Management & Information Systems Review
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    • v.30 no.4
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    • pp.253-292
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    • 2011
  • This study is significant of groping for the autonomous perspective of a medication system for the establishment of harmonious regional labor-management relationship and investigating a plan to minimize previously labor disputes through both analyzing mediation cases and finding out any core issue from the labor-management relationship, with matters experienced in the mediation field when I had served as a mediator. Specially, this study has also objectives to prevent previously any labor dispute through analyzing and minimizing the issue of the labor dispute by case and to establish harmonious labor-management relationship thereby. Further since it is necessary to understand the organization and roles of the regional labor relations commission in order to understand the concrete matters in respect of the labor dispute mediation, this study shall be to explore in detail the matters relating hereto and to acquire general knowledge of mediation through case analysis. Additionally, there is little studies exploring alternative research for the establishment of reasonable labor-management relationship with core issues referred a mediation to the labor relations commission through both the position heightening of the labor relations commission and the analysis of core issues until now. Thus, this study may provide a theoretical base for raising a technique to enhance negotiation skill through acquiring the previous training or full knowledge on the approaching manner to be taken by the labor and management in the collective bargaining or wage bargaining on the basis of items analyzed by core issue. The heightening perspectives to be acquired through the analysis of 50 or more mediation cases are as follows. First, it deems to be important what position each mediation party takes. Second, the information acquired by an investigator in the preliminary investigation before holding the mediation is very importantly utilized in the mediation. Third, the gumption of mediators in charge of the mediation is very helpful for the resolution of a case. Fourth, it shall be preceding to understand dispute issues. After reviewing fully the investigation report of an investigator, if separate review is required, it is tried to hold a separate meeting and then reduce the number of issues asserted by the labor & management and, if the number of such issues is reduced, the mediation may approach to be concluded. Fifth, it shall be kept in mind that any matter other than the scope of the law be based on not the judgement of mediator but the legal interpretation. Sixth, it is necessary for both labor and management parties to take a positive approach so as to make the healthy labor & management relationship anchored. Seventh, notwithstanding the mediators are part-time and take a service attitude, it shall be encouraged to abstain from slandering or inveighing against the mediators because the mediation is taken against oneself. Eighth, it is necessary to convert the management's recognition about a labor union. Ninth, it is necessary to not raise any issue on the matters, such as time-off system and multiple labor union, etc., which are legally enforced. Tenth, it is confirmed that the regional labor relations commission plays a bridge role of narrowing down the issue difference between the labor and management.

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Study on Political Factors for Innovating Textile and Fashion Industry in Northern Gyeonggi Province (경기북부 섬유패션산업 혁신을 위한 필요 정책요인 분석연구)

  • Yoon, Chang-Ju;Hwang, Chan-Gyu;Kwon, Hun-Gong;Won, Moon-Ye
    • Journal of Convergence for Information Technology
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    • v.8 no.1
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    • pp.253-263
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    • 2018
  • Textile fashion industry is a core foundation industry, having the majority of companies with 10 or more workers, in Northern Gyeonggi Province. however the industry is mostly comprised of small unit-stream enterprises, orders are greatly reduced due to lately accelerated overseas expansion of medium/large-sized vendors and the growth-inhibiting vicious circle has being set in, as this situation causes the reduction of investment. For resolving the problems, this study proposes required political factors and concrete policy proposals by designing AHP research model(4 layers and 36 elements), based on grasp of the transitional aspect of industrial scale and business environment through analysis of various industrial statistics, preceding research such as related literature search and (industrial/academic/R&D/government) specialist opinion investigation, and then calculating relative importance and priority of each factor(element) within each layer. And for raising usefulness and availability of the research result by concretely suggesting the vision, strategies, core tasks and detailed projects in which the research model and deduced result are reflected.

Output-Only System Identification and Model Updating for Performance Evaluation of Tall Buildings (초고층건물의 성능평가를 위한 응답의존 시스템판별 및 모델향상)

  • Cho, Soon-Ho
    • Journal of the Earthquake Engineering Society of Korea
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    • v.12 no.4
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    • pp.19-33
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    • 2008
  • Dynamic response measurements from natural excitation were carried out for 25- and 42-story buildings to evaluate their inherent properties, such as natural frequencies, mode shapes and damping ratios. Both are reinforced concrete buildings adopting a core wall, or with shear walls as the major lateral force resisting system, but frames are added in the plan or elevation. In particular, shear walls in a 25-story building are converted to frames from the 4th floor level downwards while maintaining a core wall throughout, resulting in a fairly complex structure. Due to this, along with similar stiffness characteristics in the principal directions, significantly coupled and closely spaced modes of motion are expected in this building, making identification rather difficult. By using various state-of-the-art system identification methods, the modal parameters are extracted, and the results are then compared. Three frequency-domain and four time-domain based operational modal identification methods are considered. Overall, all natural frequencies and damping ratios estimated from the different identification methods showed a greater consistency for both buildings, while mode shapes exhibited some degree of discrepancy, varying from method to method. On the other hand, in comparison with analysis results obtained using the initial finite element(FE) models, test results exhibited a significant difference of about doubled frequencies, at least for the three lower modes in both buildings. To improve the correlation between test and analysis, a few manual schemes of FE model updating based on plausible reasons have been applied, and acceptable results are obtained. The advantages and disadvantages of each identification method used are addressed, and some difficulties that might arise from the updating of FE models, including automatic procedures, for such large structures are carefully discussed.

A Study on the Adolescent폭s Experiences in Domestic Violence (폭력가정 청소년의 가족폭력 경험에 관한 연구)

  • 김경희
    • Journal of Korean Academy of Nursing
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    • v.28 no.1
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    • pp.70-80
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    • 1998
  • This study is designed to contribute to the nursing intervention of adolescent domestic violence victims by describing specifically what they go through and on this basis work out a grounded theory on the adolescent's experience in domestic violence. The data were analyzed in the framework of grounded theory as mapped out by Strauss & Corbin(1990). The major findings of this research are as follows : The core category was found to be the the adaptation of "Joyudeum" or “Straight jacketing”. The sub-categories identified in the process of grounded data analysis were 'menacing', 'being harassed', 'being pressed', 'being attacked', 'being strapped', 'being filled with anger'. 'getting angry', 'being oppressed', 'being strained', 'becoming hard', 'endurance', 'regulation', 'seriousness'. 'repitition'. 'being helpful', 'dependence', 'thinking oriented', 'blowing off', 'going astray', 'self-deprecating', 'shaking off', 'covering up', 'governing', 'being devoted', 'performing', 'being transformed'. 'bolting', 'being shaken', 'withdrawing', 'disliking', 'bitterness'. These categories were again grouped into 13 categories including 'threatening'. 'straight jacketing', 'tolerance', 'violence', 'supporter', 'supporting type', 'thinking oriented'. 'impulsive response', 'self-controlled', 'response', 'self-reliance', 'wandering', 'withdrawal' and pain'. Of these the five sub-categories 'being filled with anger'. 'getting angry', 'being oppressed', 'being strained', 'becoming hard' were grouped into a core category "straight jacketing". Those adolescents brought up in a violent family go through three stages of the adaptation of "straight Jacketing". that is, generation, response and adaptation. The following four theses were confirmed on the basis of repetitive relations : 1) If a subject's tolerance is strong, the episodes of the violence are frequent and serious, with the resulting straight jacketing being stronger but the subject's supporter is highly mature, the supporting type is concrete and the thinking oriented is wishful, the responses to the straight jacketing result in a self-control whose consequence is self-reliance with part of it resulted in withdrawal and pain. 2) If a subject's tolerance is weak, the episodes of the violence are frequent but not serious, with the resulting straight jacketing being weaker but the subject's supporter is immature, the supporting type is superficial and the thinking oriented is extemporary, the responses to the straight jacketing result in an impulsion whose consequence is wandering with part of it resulted in withdrawal and pain. 3) If a subject's tolerance is weak, the episodes of the violence are frequent and serious, the straight jacketing is strong, the subject's supporter is immature and the supporting type is superficial but the thinking oriented is wishful, the responses to the straight jacketing result in an impulsion whose consequence is withdrawal and pain with part of it resulted in wandering. 4) If a subject's tolerance is strong and the episodes of the violence are infrequent and not serious, the straight jacketing is weak, the subject's supporter is immature and the supporting type is superficial but the thinking oriented is wishful, the responses to the straight jacketing result in a self-control whose consequence is withdrawal and pain with part of it resulted in self-reliance.

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Productivity Analysis of Reinforced Concrete Works and Tower Crane Working Ratio for High-rise Apartment Buildings (초고층 공동주택 RC 공사의 생산성 및 타워크레인 가동율 분석)

  • Kwon, Jihun;Huh, Youngki
    • Korean Journal of Construction Engineering and Management
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    • v.22 no.1
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    • pp.55-62
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    • 2021
  • The productivity of rebar-work and form-work was analyzed with data collected from an actual high-rise construction project, and the actual utilization rates of three tower cranes were also investigated. It was found that the average productivity of the form-work increased from 12.00~8.71(㎡/man·day) in the underground and above-ground/lower-floor to 11.94~20.73(㎡/man·day) in the standard floor. Comparing the productivity of core area to outer, the former was found to be about 11% higher. Moreover, the rebar-work productivity of the outer area(1.12 ton/man·day) was approximately 9.6% higher than that of the core area for the standard floor. The average utilization rates of three TC were surveyed to be about 63.49%, and it was revealed that rainy weather(6.1%), strong winds(6.1%), holidays(17.8%), TC lifting work(5.8%), and other failures and repairs(0.07%) were the causes of non-operation. These research results are expected to be beneficial data in planning and managing the process of high-rise RC construction works in the future.

A Evaluation of Fire Behavior According to Member Thickness of Precast Prestressed Hollow Core Slab of Fire Resistance Section (프리캐스트 프리스트레스트 내화단면 중공슬래브의 부재두께에 따른 화재거동평가 )

  • Yoon-Seob Boo;Kyu-Woong Bae;Sang-Min Shin
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.27 no.1
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    • pp.1-8
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    • 2023
  • At construction sites, interest in the production of precast materials is increasing due to off-site conditions due to changes in construction site conditions due to increased labor costs and the Act on the Punishment of Serious Accidents. In particular, the precast prestressed hollow slab has a hollow shape in the cross section, so structural performance is secured by reducing weight and controlling deflection through stranded wires. With the application of structural standards, the urgency of securing fire resistance performance is emerging. In this study, a fire-resistance cross section was developed by reducing the concrete filling rate in the cross section and improving the upper and lower flange shapes by optimizing the hollow shape in the cross section of the slab to have the same or better structural performance and economic efficiency compared to the existing hollow slab. The PC hollow slab to which this was applied was subjected to a two-hour fire resistance test using the cross-sectional thickness as a variable, and as a result of the test, fire resistance performance (load bearing capacity, heat shielding property, flame retardance property) was secured. Based on the experimental results, it is determined that fire resistance modeling can be established through numerical analysis simulation, and prediction of fire resistance analysis is possible according to the change of the cross-sectional shape in the future.

Introduction of AI digital textbooks in mathematics: Elementary school teachers' perceptions, needs, and challenges (수학 AI 디지털교과서의 도입: 초등학교 교사가 바라본 인식, 요구사항, 그리고 도전)

  • Kim, Somin;Lee, GiMa;Kim, Hee-jeong
    • Education of Primary School Mathematics
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    • v.27 no.3
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    • pp.199-226
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    • 2024
  • In response to the era of transformation necessitating the introduction of Artificial Intelligence (AI) and digital technologies, educational innovation is undertaken with the implementation of AI digital textbooks in Mathematics, English, and Information subjects by 2025 in Korea. Within this context, this study analyzed the perceptions and needs of elementary school teachers regarding mathematics AI digital textbook. Based on a survey conducted in November 2023, involving 132 elementary school teachers across the country, the analysis revealed that the majority of elementary school teachers had a low perception of the introduction and need for mathematics AI digital textbooks. However, some recognized the potential for personalized learning and effective teaching support. Furthermore, among the core technologies of the AI digital textbook, teachers highly valued the necessity of learning diagnostics and teacher reconfiguration functions and had the most positive perception of their usefulness in math lessons, while their perception of interactivity was relatively low. These findings suggest the need for changing teachers' perceptions through professional development and information provision to ensure the successful adoption and use of mathematics AI digital textbooks. Specifically, providing concrete and practical ways to use the AI digital textbook, exploring alternatives to digital overload, and continuing development and research on core technologies.

Inelastic Behavior of Beam-Column Joints Composed of RC Column and RS Beams (RC 기둥과 RS 보로 이루어진 보-기둥 접합부의 비탄성 거동)

  • 김욱종;윤성환;문정호;이리형
    • Journal of the Korea Concrete Institute
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    • v.14 no.5
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    • pp.734-741
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    • 2002
  • An experimental study was carried out for beam-column joints composed of RC column and RS beams. The purpose of this study is to examine the inelastic seismic behavior for the RC-RS connection. Two interior and one exterior beam-column assemblies with variable moment ratios were tested. Experimental results showed that strength and deformability except stiffness were satisfactory. It is considered that the lack of stiffness was due to the slipping of steel beam from RS beam. The behavioral characteristics of the RC-RS connection were evaluated according to the quideline suggested by Hawkins et al. Nominal strength at 5 % joint distortion was not satisfactory, but all the other requirements, such as strength preserving capability, energy dissipation, and initial stiffness and strength ratios after peak load were satisfactory compared with the guideline. Thus it was concluded that the RC-RS connections can maintain ductility with excellent energy-dissipating capacity if being provided with appropriate reinforced structural system such as RC core wall for the initial lateral stiffness.

An Experimental Study on the Optimum Mix Design and Site Application Case of Soil Mixing Wall for Trench Stability (구벽안정성을 위한 SMW 최적배합비 및 현장적용 사례에 관한 연구)

  • Kwon, Yeong-Ho
    • Journal of the Korea Concrete Institute
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    • v.27 no.4
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    • pp.419-426
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    • 2015
  • The purpose of this study is to investigate experimentally the optimum mix design and site application case of soil mixing wall (SMW) method which is cost-effective technique for construction of walls for cutoff wall and excavation support as well as for ground improvement before constructing LNG storage tank typed under-ground. Considering native soil condition in site, main materials are selected ordinary portland cement, bentonite as a binder slurry and also it is applied $1,833kg/m^3$ as an unit volume weight of native soil, Variations for soil mixing wall are as followings ; (1) water-cement ratio 4cases (2) mixing velocity (rpm) 3levels (3) bleeding capacity and ratio, compressive strength in laboratory and site application test. As test results, bleeding capacity and ratio are decreased in case of decreasing water-cement ratio and increasing mixing velocity. Required compressive strength (1.5 MPa) considering safety factors in site is satisfied with the range of water-cement ratio 150% below, and test results of core strength are higher than those of specimen strength in the range of 8~23% by actual application of element members including outside and inside in site construction work. Therefore, optimum mix design of soil mixing wall is proposed in the range of unit cement $280kg/m^3$, unit bentonite $10kg/m^3$, water-cement ratio 150% and mixing velocity 90rpm and test results of site application case are satisfied with the required properties.

Internal Confining Stress of Internally Confined Hollow Columns under Compressive Load (압축을 받는 내부 구속 중공 RC 기둥의 내부 구속력)

  • Won, Deok Hee;Han, Taek Hee;Kim, Seungjun;Kang, Young Jong
    • Journal of Korean Society of Steel Construction
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    • v.25 no.3
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    • pp.243-254
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    • 2013
  • Internally Confined Hollow RC(ICH RC) column consisted of concrete, transverse reinforcement, longitudinal reinforcement, and inner tube. It had good strength and ductility by core concrete was become triaxial confining state with transverse reinforcement and inner tube. There were two confining stress as external confining stress and internal confining stress in an ICH RC column. While external confining stress was researched by former researchers, internal confining stress has not researched. In this paper, confining stress of both Hollow RC column and ICH RC column was investigated using FEA program. Relation between theoretical confining stress and internal confining stress was drawn by analysis results. Modified failure condition equations of inner tube were suggested to base on failure condition equations of inner tube by former researcher. When thickness of inner tube was calculated by modified equations, it could be economic because thickness of inner tube was reduced 50% compared with former researcher equations in order to same confining stress.