• Title/Summary/Keyword: grounding system

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A Study on the Components of Teacher In-Service Training Program to Improve the Professionalism in the Elementary Environmental Education (초등환경교육의 전문성 신장을 위한 교사 연수 프로그램의 구성 요소 탐색)

  • Lee, Sung-Hee;Choi, Don-Hyung
    • Hwankyungkyoyuk
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    • v.20 no.2
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    • pp.54-66
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    • 2007
  • The purpose of this study is to find identity of the elementary environmental education and inquire elements of professionalism in environmental education that elementary teachers should have. This study performed a half-structured interview in twice to the eight of elementary teachers who completed the environmental education curriculum course in a graduate school or participated in the teacher training program before. As a result, this study found that the identity of the elementary environmental education consists of the unification comprehending various subjects, the well-rounded sensitivity balancing intellectual, emotional and behavioral aspects, and the grounding in forming environmentally friendly living-habit and academic basis of environments. Moreover, this study found that the teacher training program for the specialty of the elementary environmental teachers should comprise of the following twelve components: the knowledge of overall environmental curriculum, environmental life guidance and environmental classroom management, environmental teaching skills and function, the passion and commitment about environmental education, environmental sensitivity, understanding of education studies, the values and attitude about environment, environmental behavior, understanding the relationship between environmental psychology and developing stage of child, the general education and communication/cooperation with colleagues or local community, understanding of the role as an teacher for the elementary environmental education. More importantly, it would be very crucial that the teachers themselves who are the main body of education system should recognize the their role as the professionals in order to improve the quality of education.

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Dynamic Time Constant Based High-Performance Insulation Resistance Calculation Method (동적 시정수 기반 고성능 절연 저항 계산 기법)

  • Son, Gi-Beom;Hong, Jong-Phil
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.24 no.8
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    • pp.1058-1063
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    • 2020
  • This paper presents a new insulation resistance calculation technique to prevent electric shock and fire accidents due to the dielectric breakdown in the primary insulation section of the IT ground system. The solar power generation market is growing rapidly due to the recent expansion of renewable energy and energy storage systems, but as the insulation is destroyed and fire accidents frequently occur, a device for monitoring the insulation resistance state is indispensable to the IT grounding method. Compared to the conventional algorithm that use a method of multiplying a time constant to a fixed coefficient, the proposed insulation resistance calculation method has a fast response time and high accuracy over a wide insulation resistance range by applying a different coefficient according to the values of the insulation impedance. The proposed dynamic time constant based insulation resistance calculation technique reduces the response time by up to 39.29 seconds and improves the error rate by 20.11%, compared to the conventional method.

Fault Location Estimation Algorithm in the Railway High Voltage Distribution Lines Using Flow Technique (반복계산법을 이용한 철도고압배전계통의 고장점표정 알고리즘)

  • Park, Kye-In;Chang, Sang-Hoon;Choi, Chang-Kyu
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.22 no.2
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    • pp.71-79
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    • 2008
  • High voltage distribution lines in the electric railway system placed according track with communication lines and signal equipments. Case of the over head lines is occurrence the many fault because lightning, rainstorm, damage from the sea wind and so on. According this fault caused protection device to wrong operation. One line ground fault that occurs most frequently in railway high voltage distribution lines and sort of faults is line short, three line ground breaking of a wire, and so on. For this reason we need precise maintenance for prevent of the faults. The most important is early detection and fast restoration in time of fault for a safety transit. In order to develop an advanced fault location device for 22.9[kV] distribution power network in electric railway system this paper deals with new fault locating algorithm using flow technique which enable to determine the location of the fault accurately. To demonstrate its superiorities, the case studies with the algorithm and the fault analysis using PSCAD/EMTDC (Power System Computer Aided Design/Electro Magnetic Transients DC Analysis Program) were carried out with the models of direct-grounded 22.9[kV] distribution network which is supposed to be the grounding method for electric railway system in Korea.

The e-Business Agent Prototyping System with Component Based Development Architecture (CBD 아키텍처 기반 e-비즈니스 에이전트 프로토타이핑 시스템)

  • Shin, Ho-Jun;Kim, Haeng-Kon
    • The KIPS Transactions:PartD
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    • v.11D no.1
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    • pp.133-142
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    • 2004
  • The next generation of web applications will need to be larger, more complex, and flexible Agent-oriented systems have great potential for these e-commerce applications. Agents can dynamically discover and compose e-services and mediate interactions. Development of software agents with CBD (Component Based Development) has proved to be successful in increasing speed to market of development Projects, lowering the development cost and providing better qualify. In this thesis, we propose a systemic development process for software agents using component and UML (Unified Modeling Language). We suggest a etA (e-business Agent) CBD reference architecture for layer the related components through identification and classification of general agent and e-business agent. We also propose the ebA-CBD process that is a guideline to consider the best features of existing agent oriented software engineering methodologies, while grounding agent-oriented concepts in the same underlying semantic framework used by UML. We first developed the agent components specification and modeled it with Goal, Role, Interaction, and Architecture Model. Based on this, we developed e-CPIMAS (e-Commerce Product Information Mailing Agent System) as a case study that provides the product information's mailing service according to proposed process formality. We finally describe how these concepts may assist in increasing the efficiency reusability, productivity and quality to develop the business application and e-business agent.

3-D Beam Steering Antenna for Intelligent Beam-reconfigurable System (지능형 빔 재구성 시스템을 위한 3-D 빔 조향 안테나)

  • Lee, Chang Yong;Kim, Yong-Jin;Jung, Chang Won
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.10
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    • pp.4773-4779
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    • 2012
  • In this paper we propose two types of reconfigurable 3-D beam steering antenna for intelligent or smart antenna system. Proposed antennas are composed of triangular(structure1.) or circuler(structure2.) loop structure and bended dipole antenna structure. This antenna can steer beam pattern of 6 direction at xy-plane state (0, 1, 2) and xz-plane state (3, 4, 5) by 4 switch motion with one antenna element. Antenna structure1. is symmetric equilibrium structures based on feeding point. There is no grounding point. As a result, designed antenna's gain is similar to dipole antenna. Also, As unbalanced structure by using CPWG in the form of a semicircular, structure2. is enhanced directivity. The operation frequency of antenna are 2.5 GHz(Structure1.) and 2.55 GHz(Structure2.), maximum gain is 1.04 ~ 2.06 dBi(Structure1. : Omni-directional beam), 1.6 ~ 4 dBi(structure2. : Directional beam). The overall HPBW is about over $160^{\circ}$ in the both of the xy-plane and xz-plane at structure1. and over $125^{\circ}$ at structure2.

A Quantitative Approach to the influence on the South Korean Air Transportation System in the Event of Volcanic Ash Dispersal (화산재에 따른 국내항공교통의 영향에 대한 정량화 방안)

  • LEE, Jiseon;YOON, Yoonjin
    • Journal of Korean Society of Transportation
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    • v.34 no.4
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    • pp.318-329
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    • 2016
  • There has been a growing interest on the effect of volcanic eruption on the aviation safety, air travel and economy especially after the eruption of Eyjafjallajokull in Iceland. Since volcanic eruption is influential on a large geographic region, the effect usually extends to other neighboring countries. Korea also has an active volcano named Mountain Baekdu. Hence, the need to estimate in advance the quantitative impact of the potential eruption of Mt. Baekdu on South Korean air transportation system. However, previous studies with quantitative estimation were confined to the calculation of the direct economic loss from shut down of the airports, grounding of airlines, and trade deficits caused by the eruption. Therefore, this paper introduces a new approach to assess more accurate impact simultaneously considering volcanic ash dispersal and aviation routes. This approach is then applied to a virtual scenario to predict the damage to air traffic. With further development, this method can help estimate the damage in the air transportation industry in more accurate and faster ways. Prediction outcomes can also be utilized in setting up the emergency response plan for the air transportation industry and contribute to the creation of more proactive and predictive measures in the future.

A Study on the Improvement Plan of Electrostatic Safety Management Level through Injury Analysis (재해분석을 통한 정전기 안전관리 수준 향상 방안 연구)

  • Choi, Sang-won;Jeong, Seong-Choon;Park, Jae Suk;Yang, Jeong Yeol;Byeon, Junghwan
    • Journal of the Korean Society of Safety
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    • v.34 no.5
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    • pp.37-45
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    • 2019
  • The characteristic of fire and explosion related to electrostatic discharge is that it is difficult to reproduce the electrostatic charge and discharge phenomenon in addition to the large human and material damage. Therefore, in order to prevent accidents and disasters related to electrostatic in fire and explosion hazard areas, it is important to manage the level of electrostatic in a safe manner from the perspective of system between industrial facilities and human bodies. Rule 325 of the Occupational Safety and Health Regulations, "Prevention of Fire / Explosion due to Electrostatic", requires the use of grounding, conductive materials, humidification and electrification in order to prevent the risk of disaster caused by static explosion and electrostatic in the production process. In order to comply with these measures, related technologies, standards and systems are needed from the viewpoint of preventive measures related to electrostatic in fire and explosion hazard areas, but in Korea, it is still insufficient. Therefore, technical, institutional and managerial measures are needed as a precautionary measure to improve the level of ESD safety in fire and explosion hazard areas and prevent electrostatic related injury. In Korea, we analyzed the current status and characteristics of electrostatic related disaster by using the statistics of industrial accident and fire statistics of the Ministry of Employment and Labor. We also analyzed the current status and characteristics of electrostatic related disasters in Japan using JNIOSH accidents and disasters investigation cases and JNIOSH fire accident data of Japan Fire Bureau. The purpose of this study is to compare and analyze the current status of electrostatic related accidents and disasters in Korea and Japan in order to improve the safety management of electrostatic in fire and explosion hazard areas. In order to prevent accidents and disasters in the industrial field, The technical, institutional, and managerial measures to manage the level of electrostatic in a safe state were derived from the system point of view.

A Study on the Improvement of Survival Rate of the Passengers and Crews according to FDS Analysis (FDS 분석을 통한 승객 및 선원 생존율 향상에 대한 연구)

  • Kim, Won Ouk;Kim, Jong Su;Park, Woe Chul
    • Journal of Advanced Marine Engineering and Technology
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    • v.39 no.3
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    • pp.312-317
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    • 2015
  • Seafarers can confront to evacuate from the ship with many reasons such as collision, grounding and fire accident. It believes that evacuation time from ship is very important element in order to increase survival rate in the contingency circumstance, however narrow and complex structure of ship is one of obstacle element against prompt evacuation. Taking into consideration the unique structure of ship compared to the structure of other facilities, speed of fire propagation on board ship is faster than the same size of other type facilities. Therefore, measures to prompt evacuation are required. But it comes with the behavioral constraints of the crews and passengers of the nature of operating in a complex structure with narrow vessels. Therefore, in this study, we propose a formula to be analyzed by theoretical approach and simulation methods to improve the survival rate for the crew and passenger of the ship through the ship's structural modification. We analyzed the temperature rise and visibility which are the most influential effects on the life safety in the event of fire by using a three-dimensional analysis of sight-only program Fire Dynamic Simulator (FDS) as analytical tools.

A Study on Supportive Measures to Improve the Job Training and Employment of the Married Immigrant Women by Delphi Survey (여성결혼이민자 취업향상을 위한 지원 방안에 관한 델파이분석)

  • Lee, O-Bok
    • The Journal of the Korea Contents Association
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    • v.14 no.8
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    • pp.197-206
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    • 2014
  • This research intends to explore services, programs or policies for supporting married immigrant women to qualify themselves for being employed from the professional point of view on the assumption that their desire to get a job is high. To achieve this purpose, a delphi survey was conducted with a panel of 13 experts related to multi cultural family support in three sessions from December 20, 2013 to June 5, 2014. To analyze the collected data, descriptive statistics, including frequency, percentage, the mean, and standard deviation, were implemented, and Kendall's W for the internal reliability test on the survey instrument was carried out for statistical processing. The results are as follows : from the first session, services, programs, and policies in the level of married immigrant women themselves, children, parents in law and/or husband, organizations, and government were suggested. The highest item in average is systematization of levelwise Korean teaching program. The next higher items in average are daycare service during job training, parents in law and/or husband's consideration, parenting support services, program development of the organizations, linkage and integration system among the government ministries. As a result of the Kendall's W performed for the internal reliability test of the Delphi research, it has been concluded that the professionals' view on the supportive measures' important contents was statistically identical. According to the results of the Delphi research, systematization of levelwise Korean teaching program most required for the furtherance of the married immigrant women's entering the workforce, followed by provision of the services to draw family support, a grounding teaching of Korean corporate culture, and reconsideration of the policies.

A Study on Estimation of the Course Keeping Ability of a Ship in Confined Waterways Using the MMG Model (MMG 모델을 이용한 제한수로를 운항하는 선박의 침로안정성능 추정에 관한 연구)

  • Kim, Hyunchul;Kim, In-Tae;Kim, Sanghyun;Kwon, Soo Yeon
    • Journal of Navigation and Port Research
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    • v.43 no.6
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    • pp.369-376
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    • 2019
  • Ship hydrodynamics in the confined waterways is challenging. When a ship is maneuvering in confined waterways, the hydrodynamic behavior may vary significantly because of the hydrodynamic interaction between the bottom of the ship hull and the seabed, or so-called shallow water effects. Thus, an accurate prediction of shallow water and bank effects is essential to minimizing the risk of the collision and the grounding of the ships. The hydrodynamic derivatives measured by the virtual captive model test provide a path to predicting the change in ship maneuverability. This paper presents a numerical simulation of captive model tests to predict the maneuverability of a ship in confined waterways. Also, straight and zig-zag simulation were conducted to predict the trajectory of a ship maneuvering in confined waterways. The results showed that the asymmetric flow around a ship induced by vicinity of banks causes pressure differences between the port and starboard sides and the trajectory of a ship maneuvering in confined waterways.