• Title/Summary/Keyword: Convergence problem

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The Impact of Underlying Attributes of Design Team Members on the Group Creativity (디자인팀 구성원의 내재적 속성이 그룹창의성에 미치는 영향에 관한 연구)

  • Cho, Hee-Young;Chung, Kyung-Won
    • Archives of design research
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    • v.19 no.5 s.67
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    • pp.43-54
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    • 2006
  • Creativity is an essential ability for a successful design task, mainly because design is an activity creating something new. As the sphere of design has expanded and become complex, the design task goes beyond an individual designer's capability. Therefore, it is necessary to organize a design team consisting of various team members with diverse expertises. The aim of this study is to find out the impact of fundamental attributes of members on the group creativity in order to establish a guideline for building a creative design team. Heterogeneous teams and homeogenous teams were created according to three main factors of group creativity namely, personality, field and experience. The group creativity of each team were evaluated through protocol analysis of design activities as well as the comparison of problem solving processes and outputs. It was identified that the impact of design teams on the group creativity was distinctively different in four phases of the design process (preparation, divergence, convergence, and execution) regarding creativity properties such as fluency, elaboration, originality, usefulness. Based on these findings, a schematic model for building a design team in order to enhance the group creativity by composing the most appropriate team members for each phases of the design process was developed.

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The Study on Effects of After Vision Training for Elementary School Children in Muan (무안군 소재 초등학생들의 시훈련 효과에 관한 연구)

  • Jang, Jung Un;Kim, In Suk
    • Journal of Korean Ophthalmic Optics Society
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    • v.18 no.2
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    • pp.137-142
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    • 2013
  • Purpose: This study was designed to investigate the current status of visual acuity for elementary school students in Muan-gun and to analyze improvements of their visual function after vision training for the elementary school students who have either insufficiency of accommodation or vergence. Methods: Subjective refraction, objective refraction and binocular function were examined for 335 elementary school children from year 1 to year 6 live in Muan area, and then 47 students who have symptoms of binocular dysfunction among them were selected. We analyzed and compared between before and after vision training (VT) in binocular vision function results. Results: The results show that most of the subjects had much problem in near point convergence (NPC) than accommodation. After the vision training, the average of subjects NPC was improved about 5.93 cm, from $11.57 {\pm}1.850$ cm for before VT to $5.66{\pm}0.965$ cm for after VT. After VT positive fusional vergence at near distance after VT was $19.64{\pm}3.66$ $\Delta$, which was as much as double of near phoria. Accommodative amplitude was improved from $10.02{\pm}2.566$ D for before VT to $12.30{\pm}1.397$ D for after VT, which similar to mean of expected accommodative amplitude of 11.27 years old. Conclusions: Among insufficiency of accommodation and vergence NPC was improved specially, and accommodative facility and other ocular functions were also improved. Therefore, it is considered the vision training is very effective to recover from visual function problems.

A fundamental study on the ventilation analysis method for the network-type tunnel - focused on the none hardy-cross method (네트워크형 터널의 환기해석 방법에 대한 기초연구-비 Hardy-Cross 방법을 중심으로)

  • Kim, Hyo-Gyu;Choi, Pan-Gyu;Ryu, Ji-Oh;Lee, Chang-Woo
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.18 no.3
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    • pp.291-303
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    • 2016
  • Recently, various forms of diverging sections in tunnels have been designed as the demand for underground passageway in urban areas increases. Therefore, the complexity of the ventilation system in tunnels with diverging sections requires a ventilation analysis method different from the conventional method for the straight tunnels. None of the domestic and foreign tunnel ventilation design standards specifies the method for the ventilation network analysis, and the numerical analysis methods have been most widely used. This paper aims at reviewing the ventilation network analytical method applicable as the design standard. The proposed method is based on the characteristic equations rather than the numerical analysis. Thanks to the advantages of easy application, the Hardy-Cross method has been widely applied in the fields of mine ventilation and tunnel ventilation. However, limitations with the cutting errors in the Taylor series expansion and the convergence problem mainly caused by the mesh selection algorithm have been reported. Therefore, this paper examines the applicability of the ventilation analysis method for network-type tunnels with the gradient method that can analyze flow rate and pressure simultaneously without the configuration of mesh. A simple ventilation analysis method for network-type tunnels is proposed.

A Study on Framework Development Directions for Solving Smart City Issues (스마트시티 이슈 해결을 위한 정책프레임워크 개발방향에 관한 연구)

  • Jang, Hwan-Young
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.5
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    • pp.432-443
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    • 2018
  • This study aims to present the direction of development of a policy framework to solve the problems associated with Smart Cities. For this purpose, first, after investigating the development process of domestic smart cities, we examined various cases of smart city policies being established overseas. Second, we analyzed the existing research into smart cities, in order to understand the relationship between the major issues. Third, an expert interview was conducted based on the identified issues. Fourth, we presented the direction of development of a Smart City policy framework to solve the major problems associated with domestic and foreign smart cities. In the policy framework presented in this research, after subdividing the elements used for solving each problem, we linked them with the smart city components and selected matching executable agents to prepare solutions. Then, once the deliberation process of the National Smart City Committee and the Smart Urban Service Support Organization has been completed, the government will support it financially and politically. It also suggested that it is necessary to perform continuous information gathering and monitoring work, along with the construction of a control tower to strengthen the network effect between smart city related markets. This research has significance in that it presents the procedures required for efficiently responding to the problems arising in the smart city promotion process. It is expected that it will serve as the basis for establishing policies dealing with the development and advancement of domestic smart cities in the future.

A Design of N-Screen based Monitoring System for Marine-Facility (N-Screen 기반의 해양시설물용 모니터링 시스템 설계)

  • Kim, Ji-Yoon;Oh, Jin-Seok
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.19 no.3
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    • pp.613-622
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    • 2015
  • The convergence of IT technology and marine facilities monitoring system is needed for effective monitoring systems to marine facilities. Especially the spread of smart device such as smart phone, smart pad, smart TV provide an environment that can check the status of the marine facility for marin facilities manager. However, smart phones and smart pads are used in a variety of OS used. Thus the monitoring system of the various service environments is difficult. In addition, There is inconvenience that must individually developed monitoring system for each device. In order to solve this problem NMMS (N-Screen Marine-facility Monitoring System) is proposed. NMMS is consist of Real-time monitoring system, Fault diagnosis system, Data storage system. To improve variety of smart devices accessibility, we use HTML 5. Through NMMS, marine facilities manager can use smart device such as PC, Notebook, smart phone, smart pad for marine facilities monitoring.

Analysis of Vibration Characteristics for a Molded Dry-type Potential Transformer (몰드형 건식 계기용 변압기 진동 특성 분석)

  • Kim, Moosun;Jang, Dong Uk;Kim, Seung Mo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.3
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    • pp.209-214
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    • 2017
  • Most of the present potential transformers of train vehicles are of the oil-type filled with insulating oil and are susceptible to problems such as explosion due to the increase in the internal pressure during train operation and poor reliability near the end of their life cycle. As a solution to this problem, it is necessary to develop a molded dry-type potential transformer with excellent pressure-resistance performance using insulating resin. In order to localize the product, the Korea Railroad Research Institute has been developing a molded dry-type potential transformer. As part of this research, it is necessary to analyze the vibration characteristics of the developed product and to check the transformer performance in a vibration environment. In this study, a resonance test and simulated long-term life test of the developed product were conducted according to the KS R 9144 and IEC 61373 standards, respectively, which are vibration test methods for railway vehicle parts. Their natural frequencies were analyzed by comparing the results of the numerical modal analysis and resonance test, in order to confirm their adherence to the standards. Also, the performance test after the simulated long-term life test confirmed that the operation of the developed transformer was not problematic even in a long-time vibration environment.

Numerical Analysis of Resin Filling Process for a Molded Dry-type Potential Transformer (몰드형 건식 계기용 변압기 제작을 위한 수지 충진 해석 연구)

  • Kim, Moosun;Jang, Dong Uk;Kim, Seung Mo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.12
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    • pp.511-517
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    • 2016
  • Current oil-type potential transformers for trains are filled with insulating oil, which could have problems like explosions due to rising inner pressure during train operation. Therefore, mold and dry-type potential transformers are being developed to prevent explosions. One problem in manufacturing mold-type transformers is preventing void formation around the coiled core inside the mold during epoxy filling, which could cause an electrical spark. Micro voids can remain in the resin after filling, and macro voids can occur due to the structure shape. A transformer that is being developed has a cavity at the junction of the core and the coil for better performance, and when highly viscous epoxy flows inside the cavity channel, macro voids can form inside it. Therefore, in this study, the free-surface flow of the mold filling procedure was analyzed numerically by applying the VOF method. The results were used to understand the phenomena of void formation inside the cavity and to modify the process conditions to reduce voids.

Implementation a of data repeating system using solar charging and develop algorithm for data repeating in the pasture (산지초지에서 한우 활동량 정보 수집을 위한 데이터 중계 알고리즘 및 시스템 구현)

  • Kim, Suc-Jun;Kim, Jong-Won;Kim, Chun-Su
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.11
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    • pp.285-293
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    • 2016
  • In the paper, we propose a data transmission repeating system that allows data transmission for the effective supervision of cows grazing in the pasture. It is normal practice to divide the pasture into different areas for the purpose of distributing the grazing. However, this makes it difficult to supply electrical power and transmit data, because some of the pastures are far away from the office used for collecting data. To solve this problem, we developed a repeating system that can allow data transmission in the pasture using a solar charging system that consists of a 60W solar panel, 12V/100A battery and 6A solar controller for the power supply and a data transmission algorithm which extends the range of data transmission when using the proposed repeating system. We verified the performance of the repeating system by checking whether the data transmission is successful or not when transmitting from various test points when there is an obstacle between the receiver and repeating system. We also verified the solar charging system by measuring the battery voltage when the system is operated continuously for 31 days and whether the system can supply sufficient power when the weather is cloudy or rainy for a few days. Finally, we verified the performance of the repeating system and data transmission algorithm by conducting experiments in a pasture.

A Study on the Robust Double Talk Detector for Acoustic Echo Cancellation System (음향반항 제거 시스템을 위한 강인한 동시통화 검출기에 관한 연구)

  • 백수진;박규식
    • The Journal of the Acoustical Society of Korea
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    • v.22 no.2
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    • pp.121-128
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    • 2003
  • Acoustic Echo Cancellation(m) is very active research topic having many applications like teleconference and hands-free communication and it employs Double Talk Detector(DTD) to indicate whether the near-end speaker is active or not. However. the DTD is very sensitive to the variation of acoustical environment and it sometimes provides wrong information about the near-end speaker. In this paper, we are focusing on the development of robust DTD algorithm which is a basic building block for reliable AEC system. The proposed AEC system consists of delayless subband AEC and narrow-band DTD. Delayless subband AEC has proven to have excellent performance of echo cancellation with a low complexity and high convergence speed. In addition, it solves the signal delay problem in the existing subband AEC. On the other hand, the proposed narrowband DTD is operating on low frequency subband. It can take most advantages from the narrow subband such as a low computational complexity due to the down-sampling and the reliable DTD decision making procedure because of the low-frequency nature of the subband signal. From the simulation results of the proposed narrowband DTD and wideband DTD, we confirm that the proposed DTD outperforms the wideband DTD in a sense of removing possible false decision making about the near-end speaker activity.

A Study on the Application of the Technology Tree for Water Hazard Information Platform (수재해 정보 플랫폼을 위한 기술트리 활용 방안 연구)

  • Kim, Dong-Young;Lee, Jeong-Ju;Chae, Hyo-Sok;Hwang, Eui-Ho
    • Journal of the Korean Association of Geographic Information Studies
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    • v.17 no.4
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    • pp.200-214
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    • 2014
  • Technology planning is becoming increasingly important with the rapid development and decline of technology. Technology roadmapping is a tool used to select whether the specific technique of technology planning should pursue which technology and in which time. This technology is important to secure the uncertain future since it will provide a method that is able to share the goals and strategies between organizations. Therefore, technology tree in the planning stage of the problem would be a very useful tool. In this study, both domestic and international technology tree application cases were analyzed to be able to derive a plan for ensuring that the research performed and the requirements are met for the future development and implementation of a convergence portal system. The six major systems that aim at water hazard information platform are basic information providing system, analysis information providing system, water disaster theme providing system, national disaster information system, water disaster augmented reality system and open information platform system. General standardized core technologies corresponding to the needed functions in each target system are derived through brainstorming, and classified according to the technology field to derive the technology tree.