• 한국정밀공학회지
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• 제14권11호
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• pp.135-146
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• 1997

This paper describes fault diagnosis method in complex system with hierachical structure similar to human body structure. Complex system is divided into unit, item and component. For diagnosing this hierarchical complex system, it is necessary to implement special neural network. Fault diagnosis system can forecast faults in a system and decide from current machine state signal information. Comparing with other diagnosis system for single fault, the developed system deals with multiple fault diagnosis comprising Hierarchical Neural Network(HNN). HNN consists of four level neural network, first level for item fault symptom classification, second level for item fault diagnosis, third level for component symptom classification, forth level for component fault diagnosis. UNIX IPC(Inter Process Communication) is used for implementing HNN wiht multitasking and message transfer between processes in SUN workstation with X-Windows(Motif). We tested HNN at four units, seven items per unit, seven components per item in a complex system. Each one neural newtork operate as a separate process in HNN. The message queue take charge of information exdhange and cooperation between each neural network.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.551-554
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• 2005

The method of the reduction of the automotive induction noise can be classified by the method of passive control and the method of active control. However, the passive control method has a demerit to reduce the effect of noise reduction at low frequency (below 500Hz) range and to be limited by a space of the engine room. Whereas, the active control method can overcome the demerit of passive control method. The algorithm of active control is mostly used the LMS (Least-Mean-Square) algorithm because the LMS algorithm can easily obtain the complex transfer function in real-time. Especially, When the Filtered-X LMS (FXLMS) algorithm is applied to an ANC system. However, the convergence performance of LMS algorithm goes bad when the FXLMS algorithm is applied to an active control of the induction noise under rapidly accelerated driving conditions. Thus Normalized FXLMS algorithm was developed to improve the control performance under the rapid acceleration. The advantage of Normalized FXLMS algorithm is that the step size is no longer constant. Instead, it varies with time. But there is one additional practical difficulty that can arise when a nonstationary input is used. If the input is zero for consecutive samples, then the step size becomes unbounded. So, in order to solve this problem. the Correlation FXLMS algorithm was developed. The Correlation FXLMS algorithm is realized by using an estimate of the cross correlation between the adaptation error and the filtered input signal to control the step size. In this paper, the performance of the Correlation FXLMS Is presented in comparison with that of the other FXLMS algorithms based on computer simulations.

• 대한원격탐사학회지
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• 제37권1호
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• pp.161-167
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• 2021

This paper presents the method to quantitatively evaluate the uncertainty of the semi-empirical Bidirectional Reflectance Distribution Function (BRDF) model for Himawari-8/AHI. The uncertainty of BRDF modeling was affected by various issues such as assumption of model and number of observations, thus, it is difficult that evaluating the performance of BRDF modeling using simple uncertainty equations. Therefore, in this paper, Monte-Carlo method, which is most dependable method to analyze dynamic complex systems through iterative simulation, was used. The 1,000 input datasets for analyzing the uncertainty of BRDF modeling were generated using the Second Simulation of a Satellite Signal in the Solar Spectrum (6S) Radiative Transfer Model (RTM) simulation with MODerate Resolution Imaging Spectroradiometer (MODIS) BRDF product. Then, we randomly selected data according to the number of observations from 4 to 35 in the input dataset and performed BRDF modeling using them. Finally, the uncertainty was calculated by comparing reproduced surface reflectance through the BRDF model and simulated surface reflectance using 6S RTM and expressed as bias and root-mean-square-error (RMSE). The bias was negative for all observations and channels, but was very small within 0.01. RMSE showed a tendency to decrease as the number of observations increased, and showed a stable value within 0.05 in all channels. In addition, our results show that when the viewing zenith angle is 40° or more, the RMSE tends to increase slightly. This information can be utilized in the uncertainty analysis of subsequently retrieved geophysical variables.

• 대한원격탐사학회지
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• 제28권5호
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• pp.561-571
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• 2012

변조전달함수(MTF; Modulation Transfer Function)는 광학영상의 성능을 평가하는 중요한 품질 요소 중 하나이다. 영상의 MTF 증진을 위해 영상 복원이 필요하나, 이 과정은 대표적인 부적합문제(ill-posed problem)의 하나로 특정한 해를 갖지 않는다. 영상 복원을 위한 필터에는 역 필터(IF; Inverse Filter), 의사 역 필터(PIF; Pseudo Inverse Filter), Wiener Filter(WF) 등이 있다. 이들 중 가장 일반적으로 사용되고 있는 WF는 촬영된 영상 내에서 영상과 잡음을 정확히 구분하기 어렵다는 한계를 가지고 있다. 본 논문에서는 Modified Wiener Filter(MWF)를 사용하여 부적절 문제를 풀 수 있도록 문제를 정규화 하였으며, 정규화 변수(regularization parameter)의 값을 찾기 위한 방법으로 L-곡선(L-curve)을 사용하였다. MWF의 검증을 위해 Dubaisat-1 위성의 영상을 의사 역 필터(PIF), Wiener Filter(WF), MWF로 영상 복원을 수행하였다. 복원 결과, MWF를 사용했을 때가 PIF를 사용했을 때의 결과에 비해 20.93%, WF를 사용했을 때의 결과에 비해 10.85% 더 향상된 MTF를 얻을 수 있었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1480-1484
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• 2003

This paper presents the design and development of network for housing estate security system. The system can cover up to 961 houses which can be up to 1,200 meters long transfer rate of 9,600 bps. This system uses checking and warning the abnormal situation. More over this system has ability to control switch on/off the electrical equipment in the house via AC line control system. The system consists of 4 parts. The first part is a security system of each house using MCS-51 microcontroller as a central processing unit scan 32 sensors and control 8 appliances and send alarm. The MCS-51 microcontroller received control signal via telephone used DTMF circuit. The second part is distributed two levels master/slave network implementing after RS-485 serial communication standard. The protocol its base on the OSI (Open Systems Interconnection) 7 layers protocol model design focus on speed, reliability and security of data that is transferred. The network security using encrypt by DES algorithm, message sequence, time stamp checking and authentication system when user to access and when connect new device to this system. Flow control in system is Poll/Select and Stop-and-Wait method. The third part is central server that using microcomputer which its main function are storing event data into database and can check history event. The final part is internet system which users can access their own homes via the Internet. This web service is based on a combination of SOAP, HTTP and TCP/IP protocols. Messages are exchanged using XML format [6]. In order to save the number of IP address, the system uses 1 IP address for the whole village in which all homes and appliance in this village are addressed using internal identification numbers. This proposed system gives the data transfer accuracy over 99.8% and maximum polling time is 1,120 ms.

• 한국산학기술학회논문지
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• 제5권1호
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• pp.60-64
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• 2004

32비트 RISC 프로세서인 PXA255기반 보드에 임베디드 리눅스 운영체제와 HTTP(Hyperfext Transfer Protocol) 웹서버를 포팅하여 사용자의 웹 브라우져 상에서 원격지 가택에 대한 실시간 감시가 가능한 시스템을 구현하였다. 웹 서버는 GoAhead 웹 서버2.1 버전을 교차 컴파일하여 사용하였으며 가택감시를 위한 아날로그 신호에 대한 입력을 프로세서가 받기 위해 ADC(Analog to Digital Convertor)칩인 ADC0809를 사용하였다 ADC를 위한 디바이스 드라이버를 작성하였으며 이를 웹 브라우져 상에서 실시간적으로 변하는 데이터를 모니터링하기위해 클라이언트 풀(Clieilt Pull)방식을 사용한 CGI-C 응용프로그램을 개발하였다. 감시가 가능한 요소로는 온도, 조도 그리고 가스 유출여부이며 가스 밸브와 현관문의 개폐상태를 확인할 수 있게 하였고 긴급 상황 발생시 경고음을 발생하도록 하였다 최근 홈 디지털 서비스 중에 사용자가 가장 필요로 하는 긴급 상황에 대한 감시 요구를 내장형 시스템을 사용하여 보다 적은비용으로 구현하였다.

• 재활복지공학회논문지
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• 제8권3호
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• pp.151-160
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• 2014

본 연구에서는 기존의 시/청각 방식의 운전정보 전달체계의 한계를 극복하고 더불어 교통약자들의 운전수행에 도움이 되는 자동차용 햅틱 시트 기술을 개발하고자 하였다. 이를 위해 동전형 모터 30개를 사용한 진동자극용 시트커버형 시제품과 모터드라이버모듈을 제작하였고 65세 이상의 고령 피험자들을 대상으로 실시한 가상운전상황에서의 시트진동자극에 대한 실험에서는 피험자들의 전체 진동인지 점수 평균은 3.5/4점으로 87.5%의 인지율을 보여주었다. 또한 모든 피험자가 4번의 과속경고신호를 모두 인지하는 결과를 보여주었다. Trail Making Test 점수에 따른 그룹별 진동인지점수에 대한 통계분석 결과 유의한 차이가 발견되지 않았고 시각기능과 인지기능이 저하된 고령자라도 진동을 인지하는 촉각기능은 동등한 능력을 보여주는 결과를 얻었으며 이 결과는 고령운전자에 대한 차량 내에서의 시트를 통한 진동자극의 운전정보 유용성을 보여주는 것으로 사료된다.

• 한국수정란이식학회지
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• 제32권3호
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• pp.159-163
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• 2017

The artificial insemination (AI) is one of the best assisted reproductive technologies for increasing reproductive capacity and facilitating the genetic improvement in farm animals. AI has been used in Uganda for over 60 years, but a small population of the total herd has been used. This study was conducted to investigate the efficacy of AI with estrus synchronization technique and to propose ways of improving the productivity of dairy farms through AI services in Uganda. In total, 78 cows from 11 dairy farms were selected for timed-AI. Synchronization was performed according to the ovsynch programs followed by AI using frozen semen from Korean Holstein (0.5 ml straws). Pregnancy rate was varying among farms (0-50%) and the overall pregnancy rate was 28.2%. Cows in luteal phase at the time of treatment was 40.0% whereas that in follicular phase was 20.8%. After treatment, cows that showed normal estrus signal were 45.5% (25/55). Abnormal estrus was categorized into pre-estrus (9.1%), cystic ovaries (21.8%), anestrus (18.2%) and delayed ovulation (5.5%), respectively. These results imply that an assured protocol for timed-AI should be developed to improve the productivity of dairy farms through AI services in Uganda.

• Bulletin of the Korean Chemical Society
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• 제19권6호
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• pp.654-660
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• 1998

$[Fe^{II}Fe^{III}BPLMP(OAc)_2](BPh_4)_2$ (1), a new model for the reduced form of the purple acid phosphatases, has been synthesized by using a dinucleating ligand, 2,6-bis[((2-pyridylmethyl)(6-methyl-2-pyridylmethyl)amino) methyl]-4-methylphenol (HBPLMP). Complex I has been characterized by X-ray diffraction method as having (μ-phenoxo)bis(acetato)diiron core. Complex 1 was crystallized in the monoclinic space group C2/c with the following cell parameters: a=41.620(6) Å, b=14.020(3) Å, c=27.007(4) Å, β=90.60(2)°, and Z=8. The iron centers in the complex 1 are ordered as indicated by the difference in the Fe-O bond lengths which match well with typical $Fe^{III}-O\; and\; Fe^{II}-O$ bond lengths. Complex 1 has been studied by electronic spectral, NMR, EPR, SQUID, and electochemical methods. Complex 1 exhibits strong bands at 592 nm, 1380 nm in $CH_3CN$ (ε = 1.0 × 103 , 3.0 × 102). These are assigned to $phenolate-to-Fe^{III}$ and intervalence charge-transfer transitions, respectively. Its NMR spectrum exhibits sharp isotropically shifted resonances, which number half of those expected for a valence-trapped species, indicating that electron transfer between $Fe^{II}\;and\;Fe^{III}$ centers is faster than NMR time scale. This complex undergoes quasireversible one-electron redox processes. The $Fe^{III}_2/Fe^{II}Fe^{III}\;and\;Fe^{II}Fe^{III}/Fe^{II}_2$ redox couples are at 0.655 and -0.085 V vs SCE, respectively. It has $K_{comp}=3.3{\times}10^{12}$ representing that BPLMP/bis(acetate) ligand combination stabilizes a mixed-valence $Fe^{II}Fe^{III}$ complex in the air. Complex 1 exhibits a broad EPR signal centered near g=1.55 which is a characteristic feature of the antiferromagnetically coupled high-spin $Fe^{II}Fe^{III}$ system $(S_{total}=1/2)$. This is consistent with the magnetic susceptibility study showing the weak antiferromagnetic coupling $(J= - 4.6\;cm^{-1},\; H= - 2JS_1{\cdot}S2)$ between $Fe^{II}\; and \;Fe^{III}$center.

• 한국항행학회논문지
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• 제22권2호
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• pp.57-63
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• 2018

항공기 발사용 유도무기는 자체점검시험(BIT; built in test) 뿐만 아니라 MIL-STD-1760표준을 준수하여 전원, 이산신호, MUX(multiplexer)통신 등 다양한 시험을 수행해야 시스템 안전성 및 신뢰성이 입증된다. 본 사례 연구 목적은 MIL-STD-1760E 기반 항공기-무장간 연동용 테스트 벤치 구축을 통하여 공대지 유도탄 개발 시 유도탄 전원인가부터 표적정보 입력, 전달정렬, 유도탄 분리 절차에 이르기까지 정의된 TIME LINE에 의거 유도탄 발사 시퀀스 구현 방안을 제시하기 위함이고, 추가적으로 오류삽입기능을 통해 비 활성탄에서 시험할 수 없는 항목까지 검증 범위를 극대화하는 참조 방안이 될 수 있다.