• Title/Summary/Keyword: Structural details

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Experimental Study on RC Frame Structures with Non-Seismic Details Strengthened by Externally-Anchored Precast Wall-Panel Method (EPWM) (외부 앵커압착형 프리캐스트 벽체로 보강된 비내진 상세를 갖는 철근콘크리트 골조에 대한 실험적 연구)

  • Choi, Seung-Ho;Hwang, Jin-Ha;Lee, Deuck Hang;Kim, Kang Su;Kwon, Yong-Keun;Kim, Kil-Hee
    • Journal of the Korea Concrete Institute
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    • v.27 no.4
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    • pp.451-458
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    • 2015
  • The infill-wall strengthening method has been widely used for the seismic performance enhancement of the conventional reinforced concrete (RC) frame structures with non-seismic detail, which is one of the promising techniques to secure the high resisting capacity against lateral forces induced by earthquake. During the application of the infill-wall strengthening method, however, it often restricts the use of the structure. In addition, it is difficult to cast the connection part between the wall and the frame, and also difficult to ensure the shear resistance performances along the connection. In this study, an advanced strengthening method using the externally-anchored precast wall-panel (EPCW) was proposed to overcome the disadvantages of the conventional infill-wall strengthening method. The one-third scaled four RC frame specimens were fabricated, and the cyclic loading tests were conducted to verify the EPCW strengthening method. The test results showed that the strength, lateral stiffness, energy dissipation capacity of the RC frame structures strengthened by the proposed EPCW method were significantly improved compared to the control test specimen.

Evaluation of Vibration and Structural Performance of an Innovative Sliding Step Steel Stair Using Full-Scale Mock-up Test (실물대 목업실험에 의한 슬라이딩스텝 철골계단의 진동 및 구조성능 평가)

  • Kim, Sung Yong;Lee, Cheol Ho;Kim, Na Eun;Cho, Sung Sang;Chung, Woon Ok
    • Journal of Korean Society of Steel Construction
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    • v.26 no.6
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    • pp.511-522
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    • 2014
  • In this study, an innovative steel stair system is presented which enables rapid erection and high quality control in both residential and office building construction. This system features two lightweight steel stringers of box shape, bolted connections easy to absorb construction tolerance, and stair steps movable transversely (or sliding steps) such that the work space needed for concrete stairway wall could be easily provided. In this type of stairway system, other than providing robust connecting details, ensuring vibration performance is especially important since this system may be vibration-sensitive due to lightweight nature and/or probable low damping. To tackle these issues, a series of full-scale mock-up tests were conducted by using box-shape stringer members with or without concrete-fill. The connection system was shown to be sufficiently stiff and strong, or it remained elastic even under the 160% of service load level. Among the seven stringer alternatives, five exhibited satisfactory vibration performance according to the related North American and European acceptance criteria.

Seismic Tests of Steel Beam-to-column Moment Connections with Inclined End-plate Beam Splice (경사단부강판 보 이음을 갖는 강재 보-기둥 모멘트접합부의 내진실험)

  • Lim, Jong Jin;Kim, Dong Gwan;Lee, Sang Hyun;Park, Choul Soo;Lee, Chang Nam;Eom, Tae Sung
    • Journal of Korean Society of Steel Construction
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    • v.29 no.2
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    • pp.181-192
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    • 2017
  • A beam splice method using inclined end-plates and high-strength tension bolts was developed. The end-plates welded to a bracket and a spliced beam are connected each other by using the tension bolts. In the present study, six exterior beam-to-column moment connections were tested under cyclic loading. Test parameters were the end-plate details and bolt arrangements. All specimens were designed so that moment resistances of the end-plates and bolts were greater than the required moment at the beam splice, in accordance with the design methods of AISC Design Guide 4. Test results showed that in the beam splices with the extended end-plates, the beam moment successfully transferred to the bracket, without any defeats such as excessive prying action of the end plates and brittle failure at the end plate-to-beam flange weld joints. However, the deformation capacities of the overall beam-to-column connections were limited due to the brittle failure of the beam-to-column flange weld joints. From the test results, recommendations for seismic design and detailing of the beam-to-column moment connection with inclined end-plate beam splice were given.

Mediating Effects of Intrinsic Motivation on The Relationship Between Positive Psychological Capital, Psychological Empowerment and Creativity (긍정심리자본, 심리적 임파워먼트와 창의성의 관계에서 내재적 동기의 매개효과 검증)

  • Choi, Ik-Sung;Chang, Young-Chul
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.6
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    • pp.3571-3586
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    • 2014
  • This study examined the relationship among PsyCap(positive psychological capital), psychological empowerment, personal creativity and verified the mediated effects of intrinsic motivation in this relationship using the SEM(Structural Equation Model). For this study, the data was collected through on/off-line surveys of members and managers from 12 different enterprises. Among the 418 answers from voluntary participating employees, 332 answers were finally used for statistical analysis. The results were as follows. First, PsyCap had a positive influence on the intrinsic motivation and personal creativity. Second, Psychological Empowerment had a positive influence on intrinsic motivation, but psychological empowerment has no influence on creativity. Third, intrinsic motivation had a meaningful influence by partially mediating PsyCap and personal creativity but completely mediated psychological empowerment and personal creativity. This study focused on intrinsic motivation among the internal factors that have influences on showing personal creativity and has importance in the point that it has suggested the statistical significance by analyzing the psychological/emotional mechanism to reinforce this intrinsic motivation in a positive way. Positive analysis on the relationships among these variables suggests a theoretical meaning on providing a future direction for the study and practical meaning on providing ideas to reinforce the employees' personal creativity. The details of this study are followed in the main text.

Online Document Mining Approach to Predicting Crowdfunding Success (온라인 문서 마이닝 접근법을 활용한 크라우드펀딩의 성공여부 예측 방법)

  • Nam, Suhyeon;Jin, Yoonsun;Kwon, Ohbyung
    • Journal of Intelligence and Information Systems
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    • v.24 no.3
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    • pp.45-66
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    • 2018
  • Crowdfunding has become more popular than angel funding for fundraising by venture companies. Identification of success factors may be useful for fundraisers and investors to make decisions related to crowdfunding projects and predict a priori whether they will be successful or not. Recent studies have suggested several numeric factors, such as project goals and the number of associated SNS, studying how these affect the success of crowdfunding campaigns. However, prediction of the success of crowdfunding campaigns via non-numeric and unstructured data is not yet possible, especially through analysis of structural characteristics of documents introducing projects in need of funding. Analysis of these documents is promising because they are open and inexpensive to obtain. We propose a novel method to predict the success of a crowdfunding project based on the introductory text. To test the performance of the proposed method, in our study, texts related to 1,980 actual crowdfunding projects were collected and empirically analyzed. From the text data set, the following details about the projects were collected: category, number of replies, funding goal, fundraising method, reward, number of SNS followers, number of images and videos, and miscellaneous numeric data. These factors were identified as significant input features to be used in classification algorithms. The results suggest that the proposed method outperforms other recently proposed, non-text-based methods in terms of accuracy, F-score, and elapsed time.

A Study on a Classical Construction Paradigm in Modern Fashion (현대 패션에 나타난 고전적 조형 패러다임에 관한 연구)

  • Kim Hye-Young;Lee Shin-Young
    • The Research Journal of the Costume Culture
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    • v.13 no.6 s.59
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    • pp.960-976
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    • 2005
  • Classicism pursued beauty comprised of a perfect form, and beauty was perceived as a state of sufficiency. Accordingly, a completed and permanent beauty was sought after; as a result, a perfect and flawless form became the mainstream, and there was an effort to visualize the eternal proportional perfection. In classicism, forms were perfectly embodied with systematic inevitability and absolute inflexibility, by which an extremely clear aspect appeared. This study analyzes a classical construction paradigm in modern fashion according to the five categories: 'Harmony and order by numerical proportion', 'Clear form', 'Simplification of form and two-dimensional Seh-form', 'Completed contracture structure', and 'Pluralistic unification', and the respective formative characteristics are as follows. First, in terms of the formative aspect of modern fashion,'Harmony and order by numerical proportion' results from thorough observance of extreme and golden section (proportion of 5 :8) which was an aesthetic standard of beautiful body in classicism. Second, 'Clear form' appears in clothes as individual clearness of structural elements expressing each part of body, and shows a well-established form possible to be grasped with equal and clear contour line. Third,'Simplification of form and two-dimensional Seh-form' comes out as form composition, single line, single layer structure, two-dimensional form and arrangement of elements of clothes through the front viewpoint caused by 2D diagramming work while fashion-designing and producing. Also, it is seen that two-dimensional proportion which is composed of sections through various harmonious lines and sides according to the simple two-dimensional compatibility principle is accomplished. Fourth, 'Completed contracture structure' emerges as an expression of stationariness, in other words, fixation of an overall impression. This is a tendency that the overall form is grasped as a fixedly intact shape without a big change of the silhouette of clothes. Fifth, 'Pluralistic unification' means that it respectively emphasizes all the parts composing clothes by making them individually independent at the same time as each element is inclusively shown with the harmony of the overall silhouette of clothes and many other details. This study examined classical formative characteristics through a theoretical research on a formative paradigm revealing the classical style. Also, the significance of classical or rational value of art was illuminated by observing what characteristics a classical formation paradigm shows in modern fashion. As a result, classical characteristics in modern fashion prove that classicism is not a merely past construction style separated from the present but a construction paradigm deeply involved in our reason system.

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Content Analysis-based Adaptive Filtering in The Compressed Satellite Images (위성영상에서의 적응적 압축잡음 제거 알고리즘)

  • Choi, Tae-Hyeon;Ji, Jeong-Min;Park, Joon-Hoon;Choi, Myung-Jin;Lee, Sang-Keun
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.48 no.5
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    • pp.84-95
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    • 2011
  • In this paper, we present a deblocking algorithm that removes grid and staircase noises, which are called "blocking artifacts", occurred in the compressed satellite images. Particularly, the given satellite images are compressed with equal quantization coefficients in row according to region complexity, and more complicated regions are compressed more. However, this approach has a problem that relatively less complicated regions within the same row of complicated regions have blocking artifacts. Removing these artifacts with a general deblocking algorithm can blur complex and undesired regions as well. Additionally, the general filter lacks in preserving the curved edges. Therefore, the proposed algorithm presents an adaptive filtering scheme for removing blocking artifacts while preserving the image details including curved edges using the given quantization step size and content analysis. Particularly, WLFPCA (weighted lowpass filter using principle component analysis) is employed to reduce the artifacts around edges. Experimental results showed that the proposed method outperforms SA-DCT in terms of subjective image quality.

Flexural Tensile Strength of CJP Groove Welded Joints Connecting Thick HSA800 Plates (HSA800 후판재의 완전용입 맞댐용접부 휨-인장강도 실험)

  • Lee, Cheol Ho;Kim, Dae Kyung;Han, Kyu Hong;Park, Chang Hee;Kim, Jin Ho;Lee, Seung Eun;Kim, Do Hwan
    • Journal of Korean Society of Steel Construction
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    • v.26 no.5
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    • pp.407-418
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    • 2014
  • As a continuing work of previously conducted standard tension tests, full-scale flexural tests were conducted in this study to assess the structural performance the CJP groove welded joints connecting thick HSA800 plates. Two welding electrodes were available at the time of this experimental research; one was GMAW-based electrode A and the other FCAW-based electrode B. Three full-scale box-type beam specimens with single bevel- and V-groove CJP welded joints were fabricated from 60mm and 25mm thick HSA800 plates according to the AWS-prequalified groove welded joint details. In designing the specimens, all possible limit states like local and lateral torsional buckling were carefully controlled in order to induce flexural plastic yielding or eventual joint fracture. All the CJP joints made by both welding electrodes showed satisfactory performance and were able to transfer the tensile flange forces higher than that corresponding to the measured tensile strength of HSA800 flange plates. However, it should be noted that, during fabrication, serious concerns about the welding efficiency and workability of the GMAW-based electrode were raised by a certified welder. The fracture occurred at the unbeveled (or vertical) interface between the weldment and the base metal when the GMAW-based electrode was used in the single-bevel joint, implying the possibility of insufficient melting. Thus, the FCAW-based electrode B is again recommended as the choice of welding electrode for HSA800 plates. The limited test data of this study implies that the V-groove CJP joint should be used in favor of the single bevel CJP joint, if possible.

Development of a roller supported piston type loading platen reducing the frictional restraint along the interfaces between the specimen and platens under the biaxial loading condition (이축압축 조건에서 실험체/재하판 경계면상의 마찰저항 감소를 위한 롤러 지지된 피스톤 형태의 하중재하판의 개발)

  • SaGong, Myung;Kim, Se-Chyul;Lee, J.S.;Park, Du-Hee
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.10 no.3
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    • pp.303-312
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    • 2008
  • Multi-axial compression tests have been frequently adopted for the evaluation of material properties of rock cores and rock fracture model tests. Special care has to be applied on the boundary condition between the specimen and loading platen to draw the precise test results of the multi-axial compression tests. With the use of dry steel platen, the stress rotation will occur, due to the frictional restraint from the boundary between the specimen and loading platen. The restraint will deviate the expected test results under the conditions of the given external pressures. Various methods have been applied to reduce the side restraint along the specimen/loading platen interface. The steel brush type loading platen is one example of the attempts. In this paper, a new type of loading platen is introduced to overcome the limitation caused by the use of the brush type loading platen, which requires some internal space for the installation of the brushes. The new type of loading platen, roller supported steel piston type loading platen. is constituted of shot steel pistons which have sufficient stiffness to deliver the external pressure and the shaft type roller installed at the rear of the pistons. The pistons are designed to follow the local deformation of the specimens. In this paper, structural details of the loading platen are presented and frictional and biaxial compression tests results are shown to verify the required functions of the loading platen. Furthermore, calibration process is followed by a comparison between the test results and numerical analyses.

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An Empirical Study on the Influencing Factors of Intention to Adoption of Mobile Government Service (모바일 전자정부 서비스 수용의도의 영향요인에 관한 연구)

  • Han, Kihun;Kim, Jinsoo
    • Asia pacific journal of information systems
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    • v.23 no.3
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    • pp.77-104
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    • 2013
  • Mobile technology is accelerating innovative changes across all fields of our society as well as business environments. Especially, demands on mobile government (M-government) services have been increased gradually since e-government has improved national administration services dramatically. However, high-quality services which are acceptable to may users are not actually supplied because technical issues such as security on mobile e-government services have not solved and governance policy was not established yet. Previous studies show that most researches are devoted to technical ones or limited to theoretical exploratory study. As a result, developing useful guidelines which are practically and theoretically proved is one of the very important research issues. This study reviews the previous research works such as concept of mobile, e-government, M-government, technical trends of mobile, market situations, present status, and various case studies. And then we develop a research model with five factors, twenty four variables and seventy six measurement for measuring the influencing factors to adoption of M-government services. The model is composed of total 16 hypotheses, 22 variables, and 76 measurements. The model is analyzed by using statistical package SPSS (18.0) and AMOS (18.0) together with structural equation method based on 294 samples. The results show that the model is valid and there are statistically significant influence between ease of use and usefulness, ease of use and user's satisfactions, usefulness and intent of re-use, and user's satisfactions and intent of re-use, excepting usefulness and user's satisfaction, ease of use and intent of re-use did not affect significant influences. Especially, service quality, system quality, and relationship quality are identified as influencing factors to adaption of M-government service. The results are expected to provide a theoretical research framework which generate new research issues in M-government service area. It also can provide an useful guidelines to practical experts in successfully implementing M-government services. Further research directions are as follows. User's intents have to be studied in details by classifying users by individual, enterprise, and government as well as developing a new hypothetical model. Since M-government service is at the initial stage, longitudinal studies have to be conducted to trace the peoples' need in order to develop new high-quality mobile services.