• Title/Summary/Keyword: Field oriented control

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NEW TREND OF FIRE SCIENCE AND EIRE PROTECTION TECHNOLOGY

  • Sugahara, Shinichi
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
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    • 1997.11a
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    • pp.19-26
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    • 1997
  • Firesafety design engineerings have been mainly derived from complicated rearrangement of descriptive specifications in codes or regulations through a great number of lessons from fire disasters. In this paper, the author refers to some recent developments in the field of building fire protection. At first, the author expresses his viewpoints concerning performance-based design codes, which have been popular throughout the world as a symbol of freedom from restricted usage of building materials and components prescrived in regulation or bylaws, in spite of some conflicts between objects-oriented design method and industrial mass production. Secondly, the author introduces several innovative fire protection methods adopted for large or void spaces in building complex. Finally, the author forcasts a next development of firesafety science and technology, aimed at securing personal safety in hyperscale urban areas.

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Development of A Boom Sprayer for Effective Pest-and-Disease Control on Densed Paddy Stems (수도(水稻) 기부(基部) 방제용(防除用) 붐-형(型) 주간(株間) 살포(撒布) 장치(裝置) 개발(開發)에 관(關)한 연구(硏究))

  • Chung, Chang Joo;Chang, Young Chang
    • Journal of Biosystems Engineering
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    • v.10 no.1
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    • pp.13-23
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    • 1985
  • Spraying method from the paddy-field levee is known to give insufficient penetration of the spray droplets to the rice stem of the densely grown plants, which is generally encountered at the last stage of rice growth. This study was intended to investigate the spraying system to solve this existing problem. As an approach, it was attempted to develop the boom-with-nozzle, between-the-row application system. Several types of nozzles and their different arrangements in the boom were tested in the field to measure the penetration-reaching distance and the uniformity of spray droplet distribution. The results of the study are summarized as follows: 1. Field experiments by the spraying method from the paddy-field levee showed to have practically no penetration of the spray droplets to the portion of the plant stem with the normal flow volume generally applied and thus need for improving present spraying method. 2. It was found that, considering both the uniformity of the spray droplet distribution and performance rate, the most efficient type of nozzle in the between-the-row boom-type spraying system was one that has core-insert hollow-cone with some clearance between the cone and tip. 3. When tested by applying the spraying method of between-the-row, the nozzle pressure did not affect the uniformity of spray droplet distribution. However, the nozzle pressure had a positive effect on the penetrating-reaching distance of the facing side of the rice stem and did not affect much on that of the opposite face of the stem. It was also found that the maximum pressure to affect the penetration-reaching distance was about $10kg/cm^2$. 4. The uniformity of the spray droplet distribution in the between-the-row system was greatly affected by the height and orientation of the nozzles in the boom. Based on experimental work for the different type of the boom-with-nozzle arrangements, it is recommended that the position of nozzle is set at about 0.45 m above the ground and two nozzles in the boom are oriented to be faced with each other with some angle such that the droplet stream from the nozzle would not directly face with each other.

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Characteristic of Induction Motor Drives Fed by Three Leg and Five Leg Inverters

  • Talib, Md. Hairul Nizam;Ibrahim, Zulkifilie;Rahim, Nasrudin Abd.;Hasim, Ahmad Shukri Abu
    • Journal of Power Electronics
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    • v.13 no.5
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    • pp.806-813
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    • 2013
  • This paper aims to compare the performance of three phase induction motor drives using Five Leg Inverter (FLI) and Three Leg Inverter (TLI) configurations. An Indirect Field Oriented Control (IFOC) method using a TLI is well established and incorporated for high performance speed drives in various industries. The FLI dual motor drive system on the other hand shows good workability in the independent control of two induction motor drives simultaneously. In this experiment, the IFOC method is utilized for both drive systems, and Space Vector Pulse Width Modulation (SVPWM) is used to generate pulses for both inverters. For the FLI, the Double Zero Sequence (DZS) Injection technique is used to generate the modulation signal. The complete experiment setup is done by using a DSpace 1103 controller board. The individual motor performances are analyzed using similar schemes, equipment setups and controller parameter values. The results show similar speed performance response capability between the single motor operation using a TLI system and the two motor operation using a FLI system based on the variable speed range either in forward or reverse operation. They also show similar load rejection abilities. However, the single motor with a TLI has a better power quality aspect such as ripple current and total harmonics distortion (THD).

Person-following of a Mobile Robot using a Complementary Tracker with a Camera-laser Scanner (카메라-레이저스캐너 상호보완 추적기를 이용한 이동 로봇의 사람 추종)

  • Kim, Hyoung-Rae;Cui, Xue-Nan;Lee, Jae-Hong;Lee, Seung-Jun;Kim, Hakil
    • Journal of Institute of Control, Robotics and Systems
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    • v.20 no.1
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    • pp.78-86
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    • 2014
  • This paper proposes a method of tracking an object for a person-following mobile robot by combining a monocular camera and a laser scanner, where each sensor can supplement the weaknesses of the other sensor. For human-robot interaction, a mobile robot needs to maintain a distance between a moving person and itself. Maintaining distance consists of two parts: object tracking and person-following. Object tracking consists of particle filtering and online learning using shape features which are extracted from an image. A monocular camera easily fails to track a person due to a narrow field-of-view and influence of illumination changes, and has therefore been used together with a laser scanner. After constructing the geometric relation between the differently oriented sensors, the proposed method demonstrates its robustness in tracking and following a person with a success rate of 94.7% in indoor environments with varying lighting conditions and even when a moving object is located between the robot and the person.

Virtual Design and Construction (VDC)-Aided System for Logistics Monitoring: Supply Chains in Liquefied Natural Gas (LNG) Plant Construction

  • Moon, Sungkon;Chi, Hung-Lin;Forlani, John;Wang, Xiangyu
    • International conference on construction engineering and project management
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    • 2015.10a
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    • pp.195-199
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    • 2015
  • Many conventional management methods have emphasized the minimization of required resources along the supply chain. Accordingly, this paper presents a proposed method called the Virtual Design and Construction (VDC)-aided system. It is based on object-oriented resource control, in order to accomplish a feed-forward control monitoring supply chain logistics. The system is supported by two main parts: (1) IT-based Technologies; and (2) VDC Models. They enable the system to convey proactive information from the detection technology to its linked visualization. The paper includes a field study as the system's pre-test: the Scaffolding Works in a LNG Mega Project. The study demonstrates a system of real-time productivity monitoring by use of the RFIDbased Mobile Information Hub. The on-line 'productivity dashboard' provides an opportunity to display the continuing processes for each work-package. This research project offers the observed opportunities created by the developed system. Future work will entail research experiments aimed towards system validation.

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A Hierarchical Model Predictive Voltage Control for NPC/H-Bridge Converters with a Reduced Computational Burden

  • Gong, Zheng;Dai, Peng;Wu, Xiaojie;Deng, Fujin;Liu, Dong;Chen, Zhe
    • Journal of Power Electronics
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    • v.17 no.1
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    • pp.136-148
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    • 2017
  • In recent years, voltage source multilevel converters are very popular in medium/high-voltage industrial applications, among which the NPC/H-Bridge converter is a popular solution to the medium/high-voltage drive systems. The conventional finite control set model predictive control (FCS-MPC) strategy is not practical for multilevel converters due to their substantial calculation requirements, especially under high number of voltage levels. To solve this problem, a hierarchical model predictive voltage control (HMPVC) strategy with referring to the implementation of g-h coordinate space vector modulation (SVM) is proposed. By the hierarchical structure of different cost functions, load currents can be controlled well and common mode voltage can be maintained at low values. The proposed strategy could be easily expanded to the systems with high number of voltage levels while the amount of required calculation is significantly reduced and the advantages of the conventional FCS-MPC strategy are reserved. In addition, a HMPVC-based field oriented control scheme is applied to a drive system with the NPC/H-Bridge converter. Both steady-state and transient performances are evaluated by simulations and experiments with a down-scaled NPC/H-Bridge converter prototype under various conditions, which validate the proposed HMPVC strategy.

An Analysis on Contents of Health-Concerned Editorials in Korean Neswspapers (주요일간지(主要日刊紙)의 보건의료관계사설(保健醫療關係社說) 내용분석(內容分析))

  • Kim, Byoung-Yik
    • Journal of Preventive Medicine and Public Health
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    • v.13 no.1
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    • pp.53-66
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    • 1980
  • The editorials of the leading newspapers may reflect as well as help formulate the public opinions to a significant degree. Bearing this in mind, this study was carried out to provide information useful in formulating such public health policies that could practically meet the social interests and demands in health appearing in the editorials of the newspapers. This analysis covered the editorials of 5 leading newspapers such as Donga Ilbo, Chungang Ilbo, Hankook Ilto, Chosun Ilbo and Seoul Shinmoon for about 10 years from Jan. 1st, 1970 through Oct. 31th, 1979. The major findings are as follows: 1. The total number of health-concerned editorials in the five daily papers for the period was 1,768 or occupied 6.4% of the total editorials of the same sources. The increasing trend of frequnecy of the health-concerned editorials since 1976 indicates the increment of social interests and demands in health. Analysing the contents, environmental pollution received the greatest attention in those editorials, which was followed by medical affairs, environmental sanitation, and disease control in order in terms of frequency of appearance. However, there was a tendency that the interests in the environmental pollution, medical affairs and social welfare tended to increase year by year, whereas those in environmental hygiene and disease control comparatively decreased. 2. Motives of dealing with the health-concerned editorials were provided by announcement of the governmental policies and implementation for 25.6% and by out-breaks of the relevant events for 23.9%. This tendency coincides with the general characteristics of the editorials that reflect the timely issues. Closely analysing, however, the fact that the motives engendered by the out-breaks of the relevant events or by the season concerned comparatively tended to decrease as years pass by, indicates that the editorials tend more to seek the future-oriented demands in health rather than the current issue-oriented. 3. The editorials appeared to be more concerned with the governmental policies. 95.7% of all the editorials analysed were addressed to the government. This signifies the role of government in the field of public health and medical affairs. Their attitudes toward health-related policies of the government were much more negative than the other editorials that were addressed to the government in other fields. This suggests that the governmental interests in health were neither sufficient nor fair. 4. What the editorials most stressed were; (1) increment of governmental interests in health, (2) improvement of the governmental health administration, (3) enriching the basic statistics, and (4) development of various technologies pertinent to health affairs and disease control, and so forth. However, must of their suggestions were not concrete but rather abstract and conceptual. 5. The editorials also expressed strong interests in research area. The areas of the needed research most suggested by items are; (1) development of effective health care delivery system, (2) establishment of more practical system of calculating medical cost, (3) implementation of effective policies to control degenerative diseases, (4) division of medical care services and pharmaceutical services systems, (5) effective ways to prevent Co poisoning accidents, (6) changing status of environmental pollution and its effects upon health, and (7) status of occupational diseases, and so forth. 6. There were some editorials -not small in quantity -that have risk to mislead the public opinions as well as the health policies due to lack of professional knowledge of the writers. It is desirable to establish some kind of mechanism that screens the erroneous contents of the editorials to help prevent misleading opinions.

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Development and Application of Unplugged Activity-centered Robot for Improving Creative Problem Solving Ability (창의적 문제해결력 신장을 위한 언플러그드 활동 중심 로봇 개발 및 적용)

  • Hong, Jiyeon;Kim, Yungsik
    • Journal of The Korean Association of Information Education
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    • v.23 no.5
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    • pp.441-449
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    • 2019
  • With the introduction of the 2015 revised curriculum, software education became mandatory in elementary school. The practical subject in the content for the software education consists of information ethics, algorithms, programming, and computer science. Especially, elementary school encourages the unplugged activities. Unplugged activities are preferred among the teachers in the education field as a teaching-learning method. However, those teachers pointed out that the lack of suitable unplugged activity materials was the biggest challenge. In addition, it was pointed out that the existing materials were not suitable for achievement standards, and there are many simple playing-oriented educations that are not linked to computing activities. In this study, we developed an unplugged activity-oriented robot that can be used for the elementary students to learn the basic control structure suggested in the achievement criteria SW education and to develop creative problem solving ability through various activities using sensors. The effectiveness was verified through the software class using the developed robot in this study.

A Literature Review on the Evaluation of and Interventions for Children's Motor Function (아동의 운동기능 평가 및 중재방법에 관한 문헌 고찰)

  • Sa, Jae-Deok;Park, Hae Yean
    • Therapeutic Science for Rehabilitation
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    • v.10 no.2
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    • pp.53-74
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    • 2021
  • Objective : The purpose of this study was to examine foreign literature on the evaluation and interventions for motor functions in children. Methods : Studies in this review were identified by searching the PubMed, Cochrane Library (Embase) databases from those published form January 2010 to March 2020 using the following keywords: "motor function test" or "motor function measure" or "movement assessment" or "motor proficiency test" or "motor scale" or "motor skill" and children. Results : Of the total 37 identified studies, 14 analyzed evaluations, 23 analyzed interventions, all of which were randomized control trials. Studies on evaluations were increasingly more common, in contrast to studies on interventions for motor functions. The most frequent field of research was rehabilitation. The studies on evaluations included the AIMS and MABC-II, and GMFM was the most frequently used intervention. Interventions were most commonly used in task-oriented training (six studies). Conclusion : This study aimed to provide a basis for therapists to choose effective motor function evaluation and interventions for clinical trials by analyzing studies related to interventions for and evaluation of motor function in children.

The Implementation of Communication Emulate Based on Component For Automation System (자동화시스템을 위한 컴포넌트 기반의 통신 Emulate 구현)

  • Jeong Hwa-Young
    • Journal of Digital Contents Society
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    • v.3 no.2
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    • pp.245-254
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    • 2002
  • Currently, communication field for automation system can be divided by simple serial communication for communication between each internal devices and network base remote control system that is based on TCP/IP. In spite of great development of network, communication part for internal control is using simple RS232 base until present. Also, development techniques of system developed by object oriented program in modular programming techniques of each function unit. Currently, it developed by component base development technique that is parts unit of software. This is presented by the new alternative of software development techniques as techniques to composition independent operation unit including business logic and is connected to development of new system. Therefore, this research implemented internal communication Emulate in RS232C based on GUI that apply development techniques of component base. that is, I maked component to commnication control part between receiving and sending and, as composite it, Control part did to handling between send and receive data.

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