• 대한조선학회 특별논문집
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• 대한조선학회 2006년도 특별논문집
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• pp.112-121
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• 2006

The vertical displacement of a ship on the basis of the sea level is an important parameter for its stability and control. To indicate the displacement on operating conditions, "draft marks" are carved on the hull of the ship in various ways. One of the methods is welding. The position, shape and size of the marks are specified on the shipbuilding rules by classification societies to be checked by shipbuilders. In most cases, high-skilled workers do the welding along the drawing for the marks and welding bead becomes the marks. But the inaccuracies due to human errors and high labor cost increase the needs for automating the work process of the draft marks. In the preceding work, an indoor robot was developed for automatic marking system on flat surfaces and the work proved that the robot welding was more effective and accurate than manual welding. However, many parts of the hull structure constructed at the outdoor are cowed shapes, which is beyond the capability of the robot developed for the indoor works on the flat surface. The marking on the curved steel surface requiring the 25m elevations is one of the main challenges to the conventional robots. In the present paper, the robot capable of climbing vertical curved steel surfaces and performing the welding at the marked position by effectively solving the problems mentioned earlier is presented.

• 대한기계학회논문집A
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• 제40권7호
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• pp.685-692
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• 2016

커팅헤드 어태치먼트는 굴삭기에 부착되어 사용되며 절삭 도구인 픽커터가 커팅헤드에 배열되어 암석이나 낙후된 건물을 파쇄 또는 절삭하는 작업에 사용된다. 암석을 절삭할 때 픽 커터의 배열은 절삭 성능과 연관성이 있는 요소이다. 본 연구는 픽 배열 설계 자동화를 수행하여 설계 소요 시간 및 검증 시간을 단축시켰으며, 배열에 따른 시스템의 거동을 예측하는데 활용하였다. 픽 배열 설계 자동화 방법은 RecurDyn/ProcessNet을 통해 수행하였으며, 설계 자동화 프로그램은 Drum set, Pick load 그리고 Pick arrangement의 세 부분으로 나누어 진행하였다. 이를 통해 커팅헤드 어태치먼트의 설계 비용 절감과 다양한 메커니즘 별 전용 어태치먼트의 설계에 활용할 수 있다.

• Journal of Electrical Engineering and Technology
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• 제13권5호
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• pp.1945-1955
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• 2018

High frequency signal injection (HFI) is an alternative method for estimating rotor position of interior permanent magnet synchronous motor (IPMSM). The general method of frequency and amplitude selection is based on error tolerance and experiments, and is usually set with only one group of HF parameters, which is not efficient for different working modes. This paper proposes a novel rotor position estimation scheme by HFI with optimized frequency and amplitude, based on the mathematic model of IPMSM. The requirements for standstill and low-speed operational modes are met by applying this novel scheme. Additionally, the effects of the frequency and amplitude of the injected HF signal on the position estimation results under different operating conditions are analyzed. Furthermore, an optimization method for HF parameter selection is proposed to make the estimation process more efficient under different working conditions according to error tolerance. The effectiveness of the propose scheme is verified by the experiments on an IPMSM motor prototype.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.327-332
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• 2006

In airborne gravimetry, there are two data streams. One is the specific force measured by an air/sea gravimeter or accelerometers, the other is kinematic acceleration measured by DGPS. And the difference of them provides the gravity disturbance information. To satisfy the requirement of most applications, an accuracy of 1mGal $(1mCal=10^{-5}m/s^{2})$ with a spatial resolution of 1km is the aim of current airborne gravimetry. There are two different methods to derive the kinematic acceleration. The generally used method is to differentiate the position twice, and the position can be calculated by commercial DGPS software. The main defect of this method is that integer ambiguities need to be fixed to get the precise position solution, but it's not a trivial thing for long base line. And to fix integer ambiguities, the noisier iono-free measurement is used. When differentiation is applied, noise is amplified and will influence the accuracy of acceleration. The other method is to get carrier phase acceleration by differentiate the carrier phase first, and then using the acceleration of GPS satellite to derive the vehicle acceleration. The main advantages include that fixing integer ambiguities is not needed anymore, position can be relaxed to about 10 meters, and smoother acceleration can be got since iono-free measurement is not needed. In some literatures, it's considered that the dynamic performance of the second method is inferior to that of the first. Through analysis, it is found that the performance degradation in dynamic environment results from the simplification of the GPS carrier phase observable model. And an iterative algorithm is presented to compensate the model error. Using a dynamic GPS data from an aeromagnetic survey, the importance of this compensation is showed at last.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.91-99
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• 2017

In order to meet the thermal performance analysis accuracy requirements of high density permanent magnet synchronous motor (PMSM), a method of multi physical domain coupling thermal analysis based on control circuit, electromagnetic and thermal is presented. The circuit, electromagnetic, fluid, temperature and other physical domain are integrated and the temperature rise calculation method that considers the harmonic loss on the frequency conversion control as well as the loss non-uniformly distributed and directly mapped to the temperature field is closer to the actual situation. The key is to obtain the motor parameters, the realization of the vector control circuit and the accurate calculation and mapping of the loss. Taking a 48 slots 8 poles high density PMSM as an example, the temperature rise distribution of the key components is simulated, and the experimental platform is built. The temperature of the key components of the prototype machine is tested, which is in agreement with the simulation results. The validity and accuracy of the multi physical domain coupling thermal analysis method are verified.

• 한국항행학회논문지
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• 제12권3호
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• pp.255-262
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• 2008

본 논문은 JSP (Java Server Page) 웹 서버 기반 인터넷 웹 브라우저 용 회로부품정보 관리 시스템을 구축하였다. 설계자가 부품정보의 검색 및 신규 등록을 수행할 수 있도록 하였으며, 이를 EDA (Electronic Design Automation) 시스템과 직접 연동하여 회로 및 부품의 설계를 실 시간적으로 적용하도록 하는 웹 연동 회로부품 관리 시스템을 구현하였다. 그리하여 개별 설계자들이 작성 관리하던 EDA 시스템 부품 라이브러리를 웹 기반으로 관리 사용할 수 있도록 하여 회로설계 및 부품 개발에 효율성을 이루었다.

• 대한안전경영과학회지
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• 제17권1호
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• pp.179-192
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• 2015

In an automated industry PLC plays a central role to control the automation system. Therefore, fault free operation of PLC controlled automation system is essential in order to maximize a firm's productivity. A prior test of control system is a practical way to check fault operations, but it is a time consuming job and can not check all possible fault operation. A formal verification of PLC program could be a best way to check all possible fault situation. Tracing the history of the study on formal verification, we found three problems, the first is that a formal representation of PLC control system is incomplete, the second is a state explosion problem and the third is that the verification result is difficult to use for the correction of control program. In this paper, we propose a transformation method to reproduce the control system correctly in formal model and efficient procedure to verify and correct the control program using verification result. To demonstrate the proposed method, we provided a suitable case study of an automation system.

• Journal of Power Electronics
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• 제17권1호
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• pp.305-313
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• 2017

A novel interference isolation method is proposed by using several designed coils in capacitive power transfer systems as isolation impedances. For each designed coil, its stray parameters such as the inter-turn capacitance, coil resistance and capacitance between the coil and the core, etc. are taken into account. An equivalent circuit model of the designed coil is established. According to this equivalent circuit, the impedance characteristic of the coil is calculated. In addition, the maximum impedance point and the corresponding excitation frequency of the coil are obtained. Based on this analysis, six designed coils are adopted to isolate the interference from power delivery. The proposed method is verified through experiments with a power carrier frequency of 1MHz and a data carrier frequency of 8.7MHz. The power and data are transferred parrallelly with a data carrier attenuation lower than -5dB and a power attenuation on the sensing resistor higher than -45dB.

• 한국주거학회논문집
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• 제19권1호
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• pp.17-27
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• 2008

Recently, newly built apartments in Korea are provided various home automation (HA) systems based on information technology(IT) for residents' safer, healthier and more convenient living. However, the residents in these digital apartments are often not able to use the home automation systems effectively because of lack of their IT knowledge, attitude, or education. However, there are few researches have been done to find out the HA systems' real problems with regard to residents' aspects who use those systems everyday. The purpose of this study was to find out residents' current uses, satisfaction level and existing problems of HA systems by residents' POE. The findings of this study will give useful information to digital home construction companies to provide user-friendly digital home services for increasing users' satisfaction. One distinctive apartment equipped with home automation systems located in Seoul was selected for in-depth personal interview. The researcher developed a survey instrument and collected the data from 58 residents in January, 2007 who had been living there for more than a year. The results of the study found that critical problems were existed in several systems and they caused a lot of dissatisfaction from the residents. Also, some residents do not use several systems although they need to use them due to the burden of maintenance fee. Further detail findings and suggestions of this study were discussed.

• 한국지능시스템학회논문지
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• 제15권4호
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• pp.486-491
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• 2005

본 논문에서는 기존 홈오토메이션 시스템보다 효율적이고 능동적인 시스템 모델을 제안하며, 기존 시스템의 한계점을 해결하기 위해서 지능형 이동 로봇을 사용한다. 제안된 시스템은 집안에서 사용하기에 적합하도록 특화된 로봇을 사용하며, 이 로봇은 사람 대신 집안을 돌아다닌다. 이 시스템 모델을 HAuPIRS (Home Automation system using PDA based Intelligent Robot System) 라고 부르기로 한다. HAuPIRS제어 구조는 사용자 레벨, 인지 레벨, 실행 레벨의 세 파트로 구성된다. 이 시스템은 사용하기 쉽고, 기술의 발전에 따른 새로운 가전기기가 나오더라도 확장이 가능하다 HAuPIRS제어 구조의 성능을 검증하기 위해서 HAuPIRS 제어 구조를 기반으로 한 PBMoRo System (PDA Based Mobile Robot System) 을 만들어 실험하였다.