• Title/Summary/Keyword: current quality

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A Study on the Development & Evaluation of Defense Quality Maturity Index (국방품질성숙도지수의 개발 및 평가에 관한 연구)

  • Jeong, Younggkwon;Cho, Hyunki;Yoo, Hanjoo
    • Journal of Korean Society for Quality Management
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    • v.47 no.3
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    • pp.479-496
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    • 2019
  • Purpose: The purpose of this research is to develop defense quality evaluation model in order to improve the problem of private sector quality evaluation model and propose the total integrated defense quality management model which enables to evaluate not only large defense industry, but also small-medium industry. Methods: This paper consider the characteristics on ISO 9001 Quality Management System, single PPM, PASS and defense quality and develop defense quality maturity model and index which enables to measure the current quality management level and characteristics and to evaluate operational characteristics in each maturity level for domestic defense industry. Results: From 176 DQMS certified defense industry, the defense quality maturity level is 68,2, C grade. The large defense industry shows, 80.9, A grade; medium industry 69.7, C grade; small-medium industry shows 54.1, D grade. Through the classified types of industries, the current level of quality management of defense industries was diagnosed and the areas to be supplemented for the total quality management were identified. Conclusion: Developed DQMI can be used as the basic information for spreading quality management activities in the defense industry by diagnosing the overall quality management of existing defense industries and quantifying the ambiguity of non-metric measurements and measurement standard that were presented as the threshold of the defense quality management system certification process.

A Study on the Characteristic of Capacitor Current by Voltage Harmonics (전압 고조파에 의한 커패시터 전류 특성 해석)

  • Kim, Jong-Gyeum;Kim, Sung-Hyun;Kim, Il-Jung
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.58 no.2
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    • pp.148-153
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    • 2009
  • As the increasing of non-linear load, we have a growing interest in power quality. Power quality has come to the voltage quality. Voltage harmonics consist in at the PCC by the non-linear load. Capacitor is generally used for the power compensation and as the passive filter by the serial connection with reactor. Capacitor has low impedance as the frequency increases, so easily fall down by the harmonic component of non-linear load. Small voltage of low-order acts on quite a few at the capacitor by the current increase. In this paper, we measured the magnitude and angle of voltage at the PCC and calculated under the same condition. we checked out that lower voltage of higher order produces current magnification.

Relationships between Young Children's Day Care Experience and Their Attachment Relationships with Parents and Socioemotional Behavior Problems (영유아기의 탁아 경험과 유아의 부모에 대한 애착 및 사회정서적 문제행동과의 관계)

  • Kim, Sook Ryong
    • Korean Journal of Child Studies
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    • v.18 no.2
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    • pp.5-18
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    • 1997
  • The purpose of the current study was to determine whether preschoolers' attachment relationships with their parents and socioemotional behaviors are related to their day care experiences in infancy and at the present time. The participants consisted of 59 preschoolers and their mothers from 2-parent, white, middle-class dual earner families in Madison, Wisconsin. Preschoolers' attachment quality was measured by two representational instruments: the Separation Anxiety Test and "My Family and Friends". Mothers completed questionnaires about their family background and their children's day care history. The quality of current day care was obtained from directors' reports about regulatable features of the day care centers. Teachers completed the Preschool Behavior Questionnaire. Data was analyzed by hierarchical multiple regression analysis. The results showed that the quality of preschoolers' attachment relationships with parents were significantly related to the amount of day care during infancy, the quality of current care, and children's gender. In addition, the amount of infant day care appeared to have negative relations with children's socioemotional behavior problems as evaluated by teachers.

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Voltage Quality Analysis in Power Distribution System with Superconducting Fault Current Limiter at Grounding Line (초전도 한류기를 주변압기 접지선에 설치시 배전계통의 순간전압품질 분석)

  • Moon, Jong-Fil
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.62 no.4
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    • pp.159-163
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    • 2013
  • In this paper, voltage quality improvement is analyzed in case of Superconducting Fault Current Limiter (SFCL) installed in grounding line of main transformer in power distribution system. First, a resistive-type SFCL model is used. Next, Korean power distribution system is modeled. Finally, when SFCL is installed in the starting point of feeder and grounding line of main transformer, voltage qualities are evaluated according to various fault locations and resistance values of SFCL using PSCAD/EMTDC. The voltage quality results in case of grounding line are compared with the voltage in case of feeder.

Design and Implementation of Solar PV for Power Quality Enhancement in Three-Phase Four-Wire Distribution System

  • Guna Sekar, T.;Anita, R.
    • Journal of Electrical Engineering and Technology
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    • v.10 no.1
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    • pp.75-82
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    • 2015
  • This paper presents a new technique for enhancing power quality by reducing harmonics in the neutral conductor. Three-Phase Four-Wire (3P4W) system is commonly used where single and three phase loads are connected to Point of Common Coupling (PCC). Due to unbalance loads, the 3P4W distribution system becomes unbalance and current flows in the neutral conductor. If loads are non-linear, then the harmonic content of current will flow in neutral conductor. The neutral current that may flow towards transformer neutral point is compensated by using a series active filter. In order to reduce the harmonic content, the series active filter is connected in series with the neutral conductor by which neutral and phase current harmonics are reduced significantly. In this paper, solar PV based inverter circuit is proposed for compensating neutral current harmonics. The simulation is carried out in MATLAB/SIMULINK and also an experimental setup is developed to verify the effectiveness of the proposed method.

Enhancement of Power System Transient Stability and Power Quality Using a Novel Solid-state Fault Current Limiter

  • Fereidouni, A.R.;Vahidi, B.;Mehr, T. Hoseini;Doiran, M. Garmroodi
    • Journal of Electrical Engineering and Technology
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    • v.6 no.4
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    • pp.474-483
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    • 2011
  • Solid-state fault current limiters (SSFCL) in power systems are alternative devices to limit prospective short circuit currents from reaching lower levels. Fault current limiters (FCL) can be classified into two categories: R-type (resistive) FCLs and L-type (inductive) FCLs. L-type FCL uses an inductor to limit fault level and is more efficient in suppressing voltage drop during a fault. In contrast, R-type FCL is constructed with a resistance and is more effective in consuming the acceleration energy of generators during a fault. Both functions enhance the transient stability of the power system. In the present paper, a novel SSFCL is proposed to enhance power system transient stability and power quality. The proposed SSFCL uses both functions of an L-type and R-type FCL. SSFCL consists of four diodes, one self-turn-off IGCT, a current-limiting by-pass inductor (L), and a variable resistance parallel with an inductor for improvement of power system stability and prevention of over-voltage across SSFCL. The main advantages of the proposed SSFCL are the simplicity of its structure and control, low steady-state impedance, fast response, and the existence of R-type and Ltype impedances during the fault, all of which improve power system stability and power quality. Simulations are accomplished in PSCAD/EMTDC.

Setting the Current Air Quality Concentration Using the National Atmosphere Measurement Network

  • CHO, Dong-Myung;LEE, Ju-Yeon;KWON, Lee-Seung;KIM, Su-Hye;KWON, Woo-Taeg
    • Journal of Wellbeing Management and Applied Psychology
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    • v.4 no.3
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    • pp.23-33
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    • 2021
  • Purpose: In the course of the domestic environmental impact assessment, the current status survey was improperly conducted, and the issue of false and inaccurate environmental impact assessment reports has been raised several times recently through media reports. Research design, data and methodology: There is a continuous demand for improvement measures for the current status measurement method, such as having difficulties in securing a normal measurement date in consideration of equipment operation and rainfall days in the field. Results: In addition, in order to grasp the general air quality status of the evaluation target area, it is necessary to check the various current status concentrations by season and time series per year. However, there is a problem that is currently being carried out based on limited results such as measurement for 1 day or 3 days. Conclusions: Therefore, in this study, based on the national atmospheric measurement network, an inverse distance weighted (IDW) interpolation method was applied to calculate the current state concentration. This study suggested a method to use it in preparing the air quality item in the environmental impact assessment report.

Study on the Software Testing Demands by Major ICT Industrial Fields -Around GyeongNam Region's- (주요 ICT 산업분야별 소프트웨어 테스팅 수요에 관한 연구 -경남지역을 중심으로-)

  • Lee, Yun-Hong;Kim, Ji-Kwan
    • Journal of the Korean Society of Industry Convergence
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    • v.20 no.4
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    • pp.265-273
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    • 2017
  • Major industries in Gyeongnam area include robot and automobile manufacturing, shipbuilding, and aviation. According to the research, the mechanical part of the products has been advanced, but awareness over the improvement of quality of the software still lacks. The quality performance test presently conducted by the companies in Gyeongnam is mostly the manual performance test performed by the program manager. In order to systematize this and extend the range of using software testing tools, the current study intends to suggest the necessity for conducting a survey on demand to improve performance and securing testing tools such as measured data analysis. Accordingly, this study is going to investigate 33 companies in Gyeongnam related with software in each of the major business areas centering around the actual field and examine activities related to software quality. And after figuring out the current status of retaining testing tools, the study will suggest the ways to enhance recognition over software quality and propose ultimate solutions to solve the problems on the current stage by finding out how to share information as much as possible in order to lay the foundation for extending the range of activity for the sake of software quality.

A Study on the Characteristics of Water Quality in the Jinhae Bay (진해만해역의 수질환경특성에 관한 연구)

  • 반영남;국승기
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2004.04a
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    • pp.255-261
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    • 2004
  • Through spot-investigation and observation of water quality environment of Jinhae Bay, this conducts the sea movement simulation on the current water quality of Jinhae Bay, grasps the flowing characteristics of Jinhae Bay and carries out ocean pollution simulation by using the data collected. Sea movement simulation results are tested by using Ocean Investigation Bureau's data of tide and current, and are also used in the ocean pollution spreading simulation. Water quality spreading simulation is conducted by using the data of sea movement and data of observation and then the results are compared with data of spot investigation. COD condensity is calculated and the water quality characteristics of Jinhae Bay are grasped.

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A Novel Control Method of Resistance Spot Welding Inverter using Dynamic Resistance Characteristics for Weld Quality Improvement (용접품질 향상을 위한 저항 스폿 용접용 인버터의 동저항 특성을 이용한 새로운 제어기법)

  • Kang, Sung-Kwan;Jung, Jae-Hun;Nho, Eui-Cheol
    • The Transactions of the Korean Institute of Power Electronics
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    • v.20 no.6
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    • pp.491-497
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    • 2015
  • This study proposes a new control method for a resistance spot welding inverter to improve weld quality. The proposed method is based on the dynamic resistance characteristics of steel sheets to be welded. A point in the second peak value of the dynamic resistance occurs during one shot of the welding current flow. A constant voltage control is applied from zero to the peak point, and a constant current control is adopted from the peak point to the end of the shot. The mixed mode control of the constant voltage and current guarantees high weld quality. Experiments are conducted with a 5 kA power supply and 0.5 mm steel sheets to compare quality. Experimental results show that weld quality is improved more than 10 times that of the conventional control method.