• 디지털산업정보학회논문지
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• 제8권3호
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• pp.87-95
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• 2012

Up to now, industrial cranes play important roles as the effective machines to carry heavy loads in the manufacturing premise, in the construction field and so on. And, a crane is widely used not only to daily work but also to carry heavy materials efficiently in a construction site for prevention of accident. However, the crane operation is highly complicated even for experts. In this paper, we developed the content of the crane mounted on the controller. This content overload conditions in the operating environment for the crane operator to warn, and the operation of equipment has the capability to limit automatically. The content for crane controller is to alert the operator overload and to limit the operation of equipment for stabilizing capabilities. The content of the flexible algorithm is based on stabilizing controllers, PLC (Programmable Logic Controller) to connect for using the equipment and electrical control systems to ensure the safety of workers and to improve the ability to work possible.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.803-805
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• 1993

This paper describes the development of a digital multifunction controller for the protection, measurement and control of the high voltage customer switchboard. The magnitude of the fundamental component is estimated using a simple filter based on cross-correlation with a heptagonal wave. The characteristics of flexible relay functions such as adjustable pickup and time-dial settings, various time-magnitude curve and directional capability including measurement functions are presented. The controller implementation is carried out on two microprocessors for real time operation.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1058-1060
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• 2003

A ground control point (GCP) is a point on the surface of Earth where image coord inates and map coordinates can be identified. The GCP is useful for the geometric correction of systematic and unsystematic errors usually contained in a remotely sensed data. Especially in case of synthetic aperture radar (SAR) data, it has serious geometric distortions caused by inherent side looking geometry. In addition, SAR images are usually severely corrupted by speckle noises so that it is difficult to identify ground control points. We developed a ground point extraction algorithm that has an improved capability. An application of radargrammetry to Daejon area in Korea was studied to acquire the geometric information. For the ground control point extraction algorithm, an ERS SAR data with precise Delft orbit information and rough digital elevation model (DEM) were used. We analyze the accuracy of the results from our algorithm by using digital map and GPS survey data.

• Journal of Power Electronics
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• 제18권6호
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• pp.1627-1633
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• 2018

A constant voltage AC-DC converter based on digital assistant technology is proposed in this paper, which has rapid dynamic response capability. The converter operates in the PFM (Pulse Frequency Modulation) mode. According to the load state, the compensation current produced by the digital compensation module was injected into the CS pin to adjust the switching pulse width dynamically and improve the dynamic response. The control chip is implemented based on NEC $1{\mu}m$ 5V/40V HVCMOS process. A 5V/1.2A prototype has been built to verify the proposed control method. When the load jumps from idle to heavy, the undershoot time is only 7.4ms.

• Journal of Information Processing Systems
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• 제15권3호
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• pp.707-716
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• 2019

In this paper, we present a certificate management platform for performance assessment during recruitment using blockchain. Applicants are awarded certificates according to a predetermined level of progress based on their performances. All certificates are stored on a recruitment management platform that serves as an environment for storing and presenting all awarded certificates. The hashed information of all the certificates are stored in the blockchain, and once stored, the contents cannot be tampered with. Therefore, anyone can check the validity of the certificates using this blockchain. Our proposed platform will be useful for recruitment and application management, career management, and personal history maintenance.

• 디지털산업정보학회논문지
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• 제10권4호
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• pp.143-150
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• 2014

A high power amplifier(HPA) has widely been used in wireless communications. In order to have a maximum power efficiency, the HPA uses a saturation domain having nonlinear characteristics, which generates nonlinear distortions to decrease the transmission efficiency. In order to solve this problem, various methods to linearize HPA have been reported until now, and the pre-distorter method is very attractive among them. In this paper, a new enhanced adaptive pre-distorter method was proposed to be applied for compensating nonlinear distortions of HPA. Through computer simulations as well as the analytical analysis, it could be shown that it is possible for both conventional adaptive pre-distorter and proposed adaptive pre-distorter, to be applied for linearizing HPA. Also, the simulations results demonstrated that the proposed adaptive pre-distorter may have faster convergence speed and better capability of compensating the nonlinear distortion than the conventional adaptive pre-distorter with nearly equal computation complexity.

• 디지털산업정보학회논문지
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• 제19권4호
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• pp.127-136
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• 2023

Many research results on the traffic enforcement of illegal driving of twowheeled motor vehicles using license plate recognition are introduced. Deep learning convolutional neural networks can be used for character and word recognition of license plates because of better generalization capability compared to traditional Backpropagation neural networks. In the plates of twowheeled motor vehicles, the interdependent government and city words are included. If we implement the mutually independent word recognizers using error correction rules for two word recognition results, efficient license plate recognition results can be derived. The CPU based convolutional neural network without library under real time processing has an advantage of low cost real application compared to GPU based convolutional neural network with library. In this paper twowheeled motor vehicle license plate recognition algorithm is introduced using CPU based deep-learning convolutional neural network. The experimental results show that the proposed plate recognizer has 96.2% success rate for outdoor twowheeled motor vehicle images in real time.

• 한국산학기술학회논문지
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• 제20권12호
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• pp.636-644
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• 2019

본 연구의 목적은 장애인의 디지털정보화역량, 디지털정보화활용 수준, 일상생활만족도 간 구조적 관계를 탐색하고, 지각된 사회적 지지망 수준에 따라 구조적 관계에 차이가 있는지 확인하는 것이다. 2017년도 디지털정보격차 실태조사의 장애인 표본 데이터의 1,639명이 분석 대상이며, 구조방정식 모형 분석 방법과 다집단 분석 방법을 활용하였다. 분석 결과 첫째, 디지털정보화역량은 디지털정보화활용 수준(β=.65), 일상생활만족도(β=.08)에 직접적으로 정적 영향을 미쳤다. 그리고 디지털정보화활용 수준 또한 일상생활만족도(β=.44)에 직접적으로 정적 영향을 미쳤다. 둘째, 장애인의 디지털정보화역량이 디지털정보화활용 수준을 매개로 일상생활만족도에 영향을 미치는 간접효과(β=.29)가 통계적으로 유의한 것으로 확인되었으며, 직접효과보다 간접효과가 더 큰 것으로 나타났다. 셋째, 장애인의 지각된 사회적 지지망 수준에 관계없이 디지털정보화역량, 디지털정보화활용 수준은 일상생활만족도에 유사한 영향을 미치는 것으로 확인되었다. 본 연구결과는 장애인의 일상생활만족도를 높이기 위해서는 디지털정보화역량 향상을 위한 교육도 중요하지만, 장애인이 디지털 기기를 활용하여 여가생활, 문화생활, 사회적 상호작용, 사회참여 등이 가능한 접근성과 활용성이 높은 디지털 및 온라인 환경을 조성해 주는 것이 필요함을 시사한다.

• 전기학회논문지
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• 제58권1호
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• pp.137-146
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• 2009

We present a micromechanical digital-to-analog (DA) variable capacitor using a parallel digital actuator array, capable of accomplishing high-Q tuning. The present DA variable capacitor uses a parallel interconnection of digital actuators, thus achieving a low resistive structure. Based on the criteria for capacitance range ($0.348{\sim}1.932$ pF) and the actuation voltage (25 V), the present parallel DA variable capacitor is estimated to have a quality factor 2.0 times higher than the previous serial-parallel DA variable capacitor. In the experimental study, the parallel DA variable capacitor changes the total capacitance from 2.268 to 3.973 pF (0.5 GHz), 2.384 to 4.197 pF (1.0 GHz), and 2.773 to 4.826 pF (2.5 GHz), thus achieving tuning ratios of 75.2%, 76.1%, and 74.0%, respectively. The capacitance precisions are measured to be $6.16{\pm}4.24$ fF (0.5 GHz), $7.42{\pm}5.48$ fF (1.0 GHz), and $9.56{\pm}5.63$ fF (2.5 GHz). The parallel DA variable capacitor shows the total resistance of $2.97{\pm}0.29\;{\Omega}$ (0.5 GHz), $3.01{\pm}0.42\;{\Omega}$ (1.0 GHz), and $4.32{\pm}0.66\;{\Omega}$ (2.5 GHz), resulting in high quality factors which are measured to be $33.7{\pm}7.8$ (0.5 GHz), $18.5{\pm}4.9$ (1.0 GHz), and $4.3{\pm}1.4$ (2.5 GHz) for large capacitance values ($2.268{\sim}4.826$ pF). We experimentally verify the high-Q tuning capability of the present parallel DA variable capacitor, while achieving high-precision capacitance adjustments.

• 한국광학회지
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• 제17권5호
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• pp.420-429
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• 2006

곡률, 두께, 굴절률 오차와 같은 광축대칭 오차요인들 때문에 상면이 이동하는 디지털 카메라용 줌렌즈 광학계에서 보상자를 이동시켜서 상면을 고정시키는 조건을 가우스 괄호법을 이용하여 유도하였다. 그리고 줌렌즈 광학계의 일반적인 세 가지 형태(3군, 4군, 5군 줌렌즈)를 사용하여 이 조건의 타당성을 검증하였다. 이러한 줌렌즈 형태에서 각 면의 곡률, 두께, 굴절률 등을 공차 내에서 Monte Carlo 방법에 따라 임의로 변화시켰을 때, 보상자의 이동량의 분포가 정규분포를 이루는 것을 확인하였다. 그리고 이로부터 공정능력을 계산하여 보상자의 최대 이동량에서 이에 따른 불량률을 이론적으로 예측하는 방법을 제시하였다.