• Proceedings of the KIEE Conference
• /
• 2005.05b
• /
• pp.41-44
• /
• 2005

전기공사는 전기공사업법에 의거 전기공사업을 등록한 자에게 발주하여야 하며 도급받은 공사업자는 전기공사업법, 전기설비기술기준, 설계도서에 적합하게 시공하도록 하고 있지만, 일부 발주관서에서 전기공사를 정보통신공사업 등 다른 공사업종으로 발주하는 사례가 있어 관계법령에 의한 전기수용신청에 애로 요인이 될뿐 만 아니라 전문적인 시공능력이 결여된 자에게 시공을 의뢰할 경우 부실을 초래하여 국민의 생명과 재산에 심각한 위협이 되고 있는바, 이와 같은 폐해를 사전에 예방하고 전기공사의 설계 및 적법한 시공업체를 선정할 수 있도록 기본적인 방향을 제시하고자 한다.

• Proceedings of the KIEE Conference
• /
• 2005.05b
• /
• pp.35-40
• /
• 2005

Many industrial disasters and safety-accidents are occurred constantly in current industrial society of domestic country. Although there are many attempts to reduce the occurrence of various industrial disasters and safety-accidents through exhaustive safety trainings and strict rules applied to fieldwork in electrical construction, still those accidents are not eradicated completely. The purpose of this study is to take counter measures against similar or same safety-accidents by analyzing the types of accidents and reasons among critical accident cases, which are occurred in electrical construction field.

• Proceedings of the KSR Conference
• /
• 2011.05a
• /
• pp.1612-1617
• /
• 2011

Rolling stock needs many maintenance works because of its long service life. The maintenance of rolling stock has periodic preventive maintenance system. This periodic preventive maintenance system can't reflect the characteristics of every part. The condition-based maintenance system which reflects the functional condition of every part prevents breakdown and reduces maintenance cost. This study will analyze the records of every part by unreasonable examples of time-based preventive maintenance and reliability management activities, and discuss the necessity of maintenance system reflected the results.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.649-655
• /
• 2011

In this paper, the content to carry out the modal testing and to analyze the data as the target of the main transformer installed on KTX is mentioned. The main transformer for KTX is a structure which is over 10 Ton. For the possibility to occur a stress concentration phenomenon exists, the dynamic durability of the system is experimentally needed to understand. To do this, we obtained the vibration data using an accelerometer, an impact hammer, a measuring instrument and gained the frequency response function of the main transformer based on the acquisition data. In this content, when the theoretical model for structural analysis should be established, we think it will be used for the property verification of analytical model. Also, we expect that the measured and analysed data will offer basic research material to maintain the system and diagnose the condition by monitoring the natural frequency of the main transformer for KTX periodically.

• Journal of the Korean Society of Combustion
• /
• v.18 no.1
• /
• pp.1-6
• /
• 2013

Authors' previous works on thermoacoustic(TA) model development showed good results in predicting combustion instability characteristics in a gas turbine combustor. However, they also suggested there were some limitations in growth rate estimation, which might be related with over-simplification of flame structure. As a first trial for improving the model accuracy, the current paper introduces the modified TA model considering the actual flame location in the combustor. The combustor is divided into the unburned and the burned area before and after the flame location, and then acoustic equations are re-organized. The modified TA model results show a better accuracy in predicting the growth rate of instabilities comparing with the previous results. However, obtained results still overestimate the conditions where the combustor goes unstable. Further researches considering heat release distribution through flames are required.

• Journal of ILASS-Korea
• /
• v.25 no.3
• /
• pp.119-125
• /
• 2020

In this paper, we used Helmholtz solver based on 3D finite element method to quantitatively analyze the effects of change of gain, time delay and time delay spread, which are the main variables of flame transfer function, on combustion instability in gas turbine combustor. The effects of the variable of flame transfer function on the frequency and growth rate, which are the main results of combustion instability, were analyzed by applying the conventional heat release fluctuation model and modified one considering the time spread. The analysis results showed that the change of gain and time delay in the same resonance mode affected the frequency of the given resonance modes as well as growth rate of the feedback instability, however, the effect of time delay spread was not relatively remarkable, compared with the dominant effect of time delay.

• Proceedings of the IEEK Conference
• /
• 2000.11a
• /
• pp.469-472
• /
• 2000

Security-related issues in mobile communications are increasing. The security requirements of mobile communications for the mobile users include authentication of the mobile user, the data confidentiality, the data confidentiality and the location privacy of mobile user. These services require security features compatible with the wireline networks. However, wireless networks have many restrictions compare to wireline networks such as the limited computational capability of mobile equipment and limited resource(bandwidth) between a mobile user and a fixed network. So, security features for IMT-2000 are designed to meet the limited capacity. In this paper, we analyze the required security features and mechanism, and design network access security feature effective for IMT-2000 Systems. The design includes security functions allocation to each system. Finally, discuss the computational power of each system based on at]coated functions to it

• Proceedings of the Acoustical Society of Korea Conference
• /
• 1994.06c
• /
• pp.188-194
• /
• 1994

Code excited linear prediction speech coders exhibit good performance at data rates as low as 4800bps. But the major drawback to CELP type coders is their large computational requirements. Therefore, in this paper a comparative performance study of three pitch searching algorithms for the CELP vocoder was conducted. For each of the algorithms, a standard pitch searching algorithm was used by the full pitch searching algorithm that was implimented in the QCELP vocoder. The algorithms used in this study is to reduce the pitch searching time 1) using the skip table, 2) using the symmetrical property of the autocorrelation , and 3) using the preprocessing autocorrelation, 4) using the positive autocorrelation, 5) using the preliminary pitch. Performance scores are presented for each of the five pitch searching algorithms based on computation speed and on pitch prediction error.

• Proceedings of the KIPE Conference
• /
• 2013.11a
• /
• pp.35-36
• /
• 2013

본 논문은 EV(Electric Vehicle)에 사용되는 배터리의 충/방전 전류에 따른 SOC(State of Charge) 및 전압특성을 Matlab Simulink로 구현하였으며, 검증을 위해 양방향 DC-DC 컨버터를 설계하여 실험을 하였다. 배터리 모델에 사용된 파라미터는 Randles등가회로를 기반으로 펄스방전을 통해 추출하였고, 단자전압 계산부에 3D Look-up 테이블을 이용해 적용하였다. SOC계산부는 전류에 따른 용량변화를 보상하기 위해 Peukert Effect를 적용하였으며, FTP-75 전류패턴으로 온도($0^{\circ}C$, $25^{\circ}C$, $40^{\circ}C$)에 따라 실험한 결과 시뮬레이션의 오차율은 5%로 높은 정확도를 갖는 것을 확인을 통해 검증 하였다.

• Proceedings of the KSME Conference
• /
• 2001.06c
• /
• pp.470-475
• /
• 2001

The elevator gear box with the helical gears needs to be developed instead of the one with the worm gears to improve the efficiency. In order to develop the gear box, the analytical tool to predict the helical gear noise is necessary to meet customer's noise requirement. Gear noise is related to the loaded transmission error. Therefore, the simulation program for the loaded transmission error analysis of the helical gears is developed in this study. Using the developed program, the effects of tooth modification such as tip relief and the extent of tip relief are investigated. Finally, the procedures to determine the tip relief and the extent of tip relief are proposed.