• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.6
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• pp.357-365
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• 2022

Refrigerant mischarging is one of the most frequently occurring failure modes in air conditioners, and both undercharging and overcharging degrade cooling performance. Therefore, it is important to accurately determine the amount of charged refrigerant. In this study, a support vector machine (SVM) model was developed to multi-classify the refrigerant mischarge through steady-state identification via fuzzy clustering techniques. For steady-state identification, a fuzzy clustering algorithm was applied to the air conditioner operation data using the difference between moving averages. The identification results using the proposed method were compared with those using existing steady-state determination techniques studied through the inversed Fisher's discriminant ratio (IFDR). Subsequently, the main features were selected using minimum redundancy maximum relevance (mRMR) considering the correlation among candidate features, and an SVM multi-classification model was devised using the derived features. The proposed method achieves satisfactory accuracy and robustness from test data collected in the new domain.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.4
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• pp.366-376
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• 2002

A sensor fault detection and isolation scheme(SFDIS) is adopted to improve the reliability of direct torque controlled induction motor drives and the experimental results are discussed. Major contributions include: experimental analysis of a few important sensor faults. design and implementation of the proposed SFDIS, and the fault tolerant control system(FTCS). Although the adopted SFDIS employs only one observer for residual generation, the system has the function of fault isolation that only multiple observer schemes can have. To verify the performance of the proposed scheme, the speed control system is designed for the 2.2kW direct torque controlled Induction motor. Hardware of the control system consists of a control board using TMS320OVC33 and a power stack using IPM. Experimental results for various type of sensor faults show the effectiveness of the SFDIS and the FTCS.

• The KIPS Transactions:PartC
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• v.11C no.6 s.95
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• pp.851-862
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• 2004

RFID(Radio frequency IDentification) is a technology that automatically identifies objects containing the electronic tags by using radio wave. The multi-tag identification problem is the core issue in the RFID and could be resolved by the anti-collision algorithm. However, most of the existing anti-collision algorithms have a problem of heavy implementation cost and low performance. In this paper. we propose a new tree based memoryless anti-collision algorithm called a collision tracking tree algorithm and presents its performance evaluation results obtained by simulation. The Collision Tracking Tree algorithm proves itself the capability of an identification rate of 749 tags per second and the performance evaluation results also show that the proposed algorithm outperforms the other two existing tree-based memoryless algorithms, i.e., the tree-walking algorithm and the query tree algorithm about 49 and 2.4 times respectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.664-665
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• 2016

This paper proposes an identification system based on QR (Quick Response) code for production and disposal information of Internet of Things (IoT) devices. Three thousands and five hundreds of electronic devices have replaced and discarded in South Korea in a year, and twenty millions to fifty millions tons of e-wastes have happened throughout the world every year. According to Gartner, market research institution, the number of IoT devices will increase from 2.3 billions in 2013 to 30 billions in 2020, however, the regulations and systems which take into account environment were not prepared. The identification systems for reflecting information of devices, which are produced or discarded, are required to resolve the problem. The proposed identification system based on QR code can store much more massive data such as the producer, product's model, serial number, recycling rate, recovering rate, recyclability rate, recoverability rate than RFID (Radio-Frequency Identification). Also, users can immediately recognize production and disposal information by a QR code application in a smartphone.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.5
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• pp.15-24
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• 2008

For high-dimensional classification tasks, such as face recognition, the number of samples is smaller than the dimensionality of the samples. In such cases, a problem encountered in linear discriminant analysis-based methods for dimension reduction is what is known as the small sample size (SSS) problem. Recently, to solve the SSS problem, a way of employing a dissimilarity-based classification(DBC) has been investigated. In DBC, an object is represented based on the dissimilarity measures among representatives extracted from training samples instead of the feature vector itself. In this paper, we propose a new method of optimizing DBCs using multi-level fusion strategies(MFS), in which fusion strategies are employed to represent features as well as to design classifiers. Our experimental results for benchmark face databases demonstrate that the proposed scheme achieves further improved classification accuracies.

• The Korean Journal of Archival Studies
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• no.70
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• pp.41-83
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• 2021

After the revision of the Enforcement Decree of the Public Records Act, the archives created a management standard table for data set records management and performed management and control. Therefore, in this study, the data set record identification procedure and evaluation index were developed for systematic data set record management of archives. By applying this, a management standard table was prepared after identifying the records of 8 datasets in kr's electronic procurement system, and the evaluation was carried out according to the evaluation index, and the retention period, transfer, and collection were determined. It is hoped that this case study will be of practical use to the archives at a time when concrete examples of procedures for the management of dataset records are lacking.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.113-118
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• 2006

ECDIS의 이용과 함께 AIS, LRIT와 같은 선박식별 추적장치의 도입은 항해환경의 많은 변화를 유도하고 있다. 영국, 미국, 노르웨이, 일본 등 해운선진국들을 중심으로 전자항해의 전략개발에 관한 의제가 IMO MSC81차 회의에서 제안된 이후 2008년 MSC 제85차 회의까지 완료를 목표로 장기과제로 채택된 바가 있다. MSC 제81차 회의에서는 MAV.가 Coordinator로 하여 신규의제로 검토하도록 COMSAR 11 및 NAV 53차에 지시한 바가 있다. 본 연구에서는 국내 및 국외 전자항해 및 해양정보시스템의 동향분석을 통하여 효율적인 정보교환을 위한 해양정보통신시스템의 발전방안을 제시하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1071-1074
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• 2009

USN은 인간과 환경의 상호작용 방식의 대변혁을 초래할 수 있다는 점에서 사회 경제 문화 전반에 걸쳐 다시 한 번 인류의 삶을 근본적으로 변화시킬 수 있는 혁신적인 기술로 주목받고 있다. 최근 USN 응용 서비스에 대한 연구가 활성화 되고 있는데, 그 중 하나가 감시정찰 센서네트워크 시스템이다. 본 논문에서는 기존의 대 규모 감시정찰 센서네트워크 시스템 체계와 다른 저 전력 센서노드들로 이루어진 환경 하에서 높은 신뢰성과 탐지정확성을 가지는 식별 및 트래킹 알고리즘을 제안한다. 또한 각 알고리즘의 성능을 측정하고 평가하여 효율적인 감시정찰 센서네트워크 시스템 구축방안을 제시한다.

• Journal of Korea Multimedia Society
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• v.14 no.8
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• pp.1029-1040
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• 2011

Electronic identity (e-ID) card based on smartcard is a representative identity credential for on-line and off-line personal identification. The e-ID card can store the personal identity information securely, so that the information can be accessed fast, automated identity verification and used to determine the cardholder's authorization to access protected resources. Due to such features of an e-ID card, the number of government organizations and corporate enterprises that consider using e-ID card for identity management is increasing. In this paper, we present an authentication framework for access control system using e-ID cards by discussing the threat environment and security requirement against e-ID card. Specifically, to accomplish our purpose, we consider the Personal Identity Verification system as our target model.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.15-24
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• 2019

The optimum solutions of MOSCOS antenna arrangement were studied to solve the EMI between it and EWT mounted on an MTB. Two candidates of optimal place for MOSCOS antenna were determined by using a fishbone diagram to determine seven reasons based on 4M1E, to identify the design factors on Friis equations, and to analyze the case study of EMI related to MOSCOS. MOSCOS antenna was rearranged by the final optimal position, which was selected by measuring the Power Spectral Density (PSD) at two locations, and the proposed improvement was tested on board to determine its efficiency.