• Title/Summary/Keyword: Coordination method

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Efficient MAC Protocol for Achieving Fairness in Wireless Ad-hoc Networks under the DCF (Wireless Ad-hoc 망의 DCF환경에서 Fairness 구현을 위한 효과적인 MAC 프로토콜)

  • 임희선;박승권
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.8A
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    • pp.928-936
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    • 2004
  • This paper proposes simple and effective Contention Window (CW) adjusting algorithm to solve the fairness problem of the IEEE 802.11 under the Distributed Coordination Function (DCF). This adjusting algorithm can support variable packet length as well as both RTS/CTS access method and hidden nodes. Simulation results show that fairness problem can be very severe in the original MAC protocol of the wireless network. In case of implement our algorithm, fair sharing was enlarged prominently and the fairness sharing was improved about maximum 30%.

The Study of Mapping Coordination S/W Based on the Internet Shopping Mall for Silver Apparel

  • Lee, Yoong-Joo;Chung, Sham-Ho
    • Journal of Fashion Business
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    • v.13 no.6
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    • pp.20-30
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    • 2009
  • The purpose of this study is to develop the effective customized elderly fashion marketing process based on the web site, where older customer will be able to choose various fabrics and to try them out. This aims to establish new prototype of internet shopping mall for customized elderly fashion clothing. In this study, new method of product presentation on the online shopping mall is proposed to offer product information through 3D virtual reality. With the online shopping mall(SATC Mall) as a showcase, we presented virtual mapping system so that it enable the customers to select the fabrics and to see exactly how chosen fabric will look when applied to image of clothing. As an initial test of the application of simulation to measure 3D visualization of product, mapping software Vision Easy Map Pro Version 6.0(NedGraphics) Vision Easy Map Viewer Version 5.0(NedGraphics) were chosen and applied. By using this mapping system, the fabric change of the apparel product could be made on the internet shopping web site. However, this approach has been successful applied for presenting and customizing garment products. Future research will focus on the integration of mapping coordination into SATC Mall.

Trajectory Development of Robotic Arc Welding System for Continuous Welding of Corner Area (모서리 부위 연속 용접을 위한 아크 용접 로봇 시스템의 궤적 개발)

  • 장교근;유범상
    • Journal of Welding and Joining
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    • v.14 no.6
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    • pp.68-80
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    • 1996
  • When a workpiece is to be arc welded around the outside corner, continuous welding without welding seam in the neighborhood of comer still remains a very difficult technique. Skilled welders weld comers by delicate“hand-eye coordination”while turning the workpiece manually, However, there is not a very clear solution to this problem in robotized arc welding process. In order to solve this problem, the coordination of a robot and a positioner with one or two axes is necessary. This paper presents a method of continuous welding around the corner of workpiece using the coordinated motion of a robot and a positioner. The positioner is either revolute jointed or prismatic jointed. In this paper, a clothoid curve is chosen for welding trajectory. The clothoid curve is excellent in connecting straight and curved weld-lines with good continuity and accommodates various welding conditions. By using this welding trajectory, the deceleration, which leads to widening of the melt and the heat affected zone, at comer area is reduced with strategic rotation of robot torch in coordination with a positioner providing smooth transition of welding torch orientation. Two types of special clothoid curves are developed for different weld slope conditions. These clothoid curves are applied to the case of linear and rotary Positioners at arc welding robot work-cell.

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ISO Coordination of Generator Maintenance Scheduling in Competitive Electricity Markets using Simulated Annealing

  • Han, Seok-Man;Chung, Koo-Hyung;Kim, Balho-H.
    • Journal of Electrical Engineering and Technology
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    • v.6 no.4
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    • pp.431-438
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    • 2011
  • To ensure that equipment outages do not directly impact the reliability of the ISO-controlled grid, market participants request permission and receive approval for planned outages from the independent system operator (ISO) in competitive electricity markets. In the face of major generation outages, the ISO will make a critical decision as regards the scheduling of the essential maintenance for myriads of generating units over a fixed planning horizon in accordance with security and adequacy assessments. Mainly, we are concerned with a fundamental framework for ISO's maintenance coordination in order to determine precedence of conflicting outages. Simulated annealing, a powerful, general-purpose optimization methodology suitable for real combinatorial search problems, is used. Generally, the ISO will put forward its best effort to adjust individual generator maintenance schedules according to the time preferences of each power generator (GENCO) by taking advantage of several factors such as installed capacity and relative weightings assigned to the GENCOs. Thus, computer testing on a four-GENCO model is conducted to demonstrate the effectiveness of the proposed method and the applicability of the solution scheme to large-scale maintenance scheduling coordination problems.

Analysis of the thresholds of granular mixtures using the discrete element method

  • Jian, Gong;Jun, Liu
    • Geomechanics and Engineering
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    • v.12 no.4
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    • pp.639-655
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    • 2017
  • The binary mixture consists of two types of granular media with different physical attributes and sizes, which can be characterized by the percentage of large granules by weight (P) and the particle size ratio (${\alpha}$). Researchers determine that two thresholds ($P_S$ and $P_L$) exist for the peak shear strength of binary mixtures, i.e., at $P{\leq}P_S$, the peak shear strength is controlled by the small granules; at $P{\leq}P_L$, the peak shear strength is controlled by the large granules; at $P_S{\leq}P{\leq}P_L$, the peak shear strength is governed by both the large and small granules. However, the thresholds of binary mixtures with different ${\alpha}$ values, and the explanation related to the inner details of binary mixtures to account for why these thresholds exist, require further confirmation. This paper considers the mechanical behavior of binary mixtures with DEM analysis. The thresholds of binary mixtures are found to be strongly related to their coordination numbers $Z_L$ for all values of ${\alpha}$, where $Z_L$ denotes the partial coordination number only between the large particles. The arrangement structure of the large particles is examined when P approaches the thresholds, and a similar arrangement structure of large particles is formed in both 2D and 3D particle systems.

Analysis on the Military Look of the Paris Collections (파리 컬렉션에 나타난 밀리터리 룩 연구)

  • Chu, Mi-Kyung;Kim, Hye-Kyung
    • Journal of the Korean Society of Costume
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    • v.57 no.8
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    • pp.137-151
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    • 2007
  • This study was aimed to analyze and investigate a diversity of aesthetic values expressed in the military look designs of the Paris collections by using content analysis method to find what design characteristic and image emerged in the later 20th century. A total of 267 military look works shown in fashion magazines such as Vogue and Collezioni Donna over the period between 1996 and 2000 were collected as research data, which were classified into 5 categories such as item, silhouette, color, color coordination, fashion image. The results were summarized as follows: first, it was found that coat was the most preferred item in expressing the military look image. Second, the straight line was the most referred silhouette, which indicates that it was the most suitable silhouette in expressing he bisexual image of the military look. Third, achromatic colors such as black and white were found to be of the highest frequency, which shows that achromatic colors continued to be proposed as fashionable colors around 1996 and this influence was effected in the military look. Finally, monochromatic coordination accounted for more than half of the military look, through which it could be explained that designers utilized it greatly to make an effective expression of the masculine image.

Shear behavior of the hollow-core partially-encased composite beams

  • Ye, Yanxia;Yao, Yifan;Zhang, Wei;Gao, Yue
    • Steel and Composite Structures
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    • v.44 no.6
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    • pp.883-898
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    • 2022
  • A hollow-core partially-encased composite beam, named HPEC beam, is investigated in this paper. HPEC beam comprises I-beam, longitudinal reinforcement, stirrup, foam formwork, and cementitious grout. The foam formwork is located on both sides of the web, and cementitious grout is cast within the steel flange. To investigate the shear performance of HPEC beams, static loading tests of six HPEC beams and three control beams were conducted. The shear span ratio and the number of studs on the shear behavior of the HPECspecimens were studied. The failure mechanism was studied by analyzing the curves of shear force versus both deflection and strain. Based on the shear span ratio (𝜆), two typical shear failure modes were observed: shear compression failure when 1.6 ≤ 𝜆 ≤ 2; and diagonal compression failure when 𝜆 ≤ 1.15. Shear studs welded on the flange can significantly increase the shear capacity and integrity of HPEC beams. Flange welded shear studs are suggested. Based on the deformation coordination theory and superposition method, combined with the simplified modified compression field model and the Truss-arch model, Modified Deformation Coordination Truss-arch (M.D.C.T.) model was proposed. Compared with the shear capacity from YB9038-2006 and JGJ138-2016, the calculation results from M.D.C.T. model could provide reasonable predictions.

The Exotic Tastes and Characteristics of Colors in Matisse's Works (마티스의 이국취미와 작품에 나타난 색채)

  • Lee, Keum Hee
    • Korean Journal of Human Ecology
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    • v.24 no.2
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    • pp.267-284
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    • 2015
  • The purpose of this study is to extract the color chip from the works of Matisse with the exotic tastes, to analyze the characters of adjacent colors, and to suggest the color coordination of artistic character. The research method is based on the literature study which analyzes visual materials. The results are as follows. Considering the colors of Japanese taste, He employs vivid and strong tone in red, yellow, and blue, light tone in pink, purple, and green and deep tone in green, purple, blue and black. His color scheme is very bold and splendid. In his Algerian taste, red is very popular, but an attention should be paid in his development of orange and blue tones. In general, the usage of various tones brings colors into less relief and make the contrast of tones more conspicuous. His Spanish taste, based on red and orange, attracts attentions with strong impressions, but sometimes, dark or adjacent pale tones creates strong, mild and murky atmosphere. The Moroccan taste, based on the development of blue tones which have strong attraction implies the lightness but represents silent and calm. The Rumanian taste, represented in primary colors of red, yellow and blue and achromatic colors is bright and clear. In addition, its light tone in various colors represents peace and romance. The coordination of the exotic colors with the unique adjacent colors created by Matisse is not based on the established color coordination theory, but extracts colors in the aspect of culture borrowing. Therefore, it can double the effects of the color scheme expressed in the existing designs and be used as the global and multi-cultural design sources.

Research on the Effect of Creative Fashion Consumer Efficacy on Innovative Fashion Product Acceptance (창의적 패션소비 효능감이 혁신적 패션 제품 수용에 미치는 영향)

  • Lee, Ha Kyung;Choo, Ho Jung
    • Fashion & Textile Research Journal
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    • v.22 no.2
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    • pp.149-157
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    • 2020
  • The current study tests the effect of fashion product knowledge and confidence in fashion coordination on innovative fashion product acceptance, mediated by creative fashion consumer efficacy. Creative fashion consumer efficacy refers to a consumers' belief in the ability to consume fashion products in a creative way. The survey was conducted on 474 people between 20 and 40 years of age in a panel of online survey firms. Data was analyzed using reliability analysis and frequency analysis by SPSS 20.0 along with confirmatory factor analysis and structural equation modeling done by AMOS 20.0. The results reveal that creative fashion consumer efficacy consists of original thinking efficacy, usage expansion efficacy, problem solving efficacy, and method variation efficacy that is consistent with the original structure of creative consumption efficacy. In addition, fashion product knowledge and confidence in fashion coordination do not affect innovative fashion product acceptance. The effects of fashion product knowledge and confidence in fashion coordination on innovative fashion product acceptance are fully mediated through creative fashion consumer efficacy. The results of this study demonstrate that people who are knowledgeable, confident and associated with fashion product consumption can have a high level of creative fashion consumer efficacy that increases innovative fashion product acceptance.

The chemical reactivity of detecting tube detection equipment for incident responder (화학사고 초기대응자를 위한 검지관식 탐지장비의 반응성 연구)

  • Ahn, Seung-Young;Kim, Jungmin;Kim, Sungbum;Chun, Kwangsoo;Lee, Jin-Seon;Park, Choonhwa
    • Journal of the Society of Disaster Information
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    • v.10 no.1
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    • pp.33-39
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    • 2014
  • Chemical accidents are the cause of the accident site during the initial responders to quickly and easily see materials and concentration method for the U.S. Environmental Protection Agency(EPA) is widely used in the initial response team direct reading detection equipment used. Ministry of the tubular gas detection equipment to detect direct reading detection equipment used in the event of an accident scene, and shell-and-tube gas detector for rapid detection and identification and precise analysis of causative pollutants before about strategically can identify the quantitative and qualitative useful equipment. However, those who initially respond to the scene of a direct reading detection equipment and a simple lack of understanding of how to use the numbers only because of the way you want to check the accuracy of detection results have been raising questions about the increase. The scene of the accident in order to obtain an accurate detection results used in this paper, the Ministry of Environment of gas detectors detect tubular Kitagawa and Draeger detector tube to check the reactivity of the material on-site detection of early response of those who were to raise the accuracy of the results.