• Proceedings of the KIEE Conference
• /
• 1995.11a
• /
• pp.175-177
• /
• 1995

The sensor signal validation and failure detection system must be able to detect, isolate, and identify sensor degradation as well as provide a reconstruction of the measurements. In this study, this is accomplished by combining the neural network, the Generalized Consistency Checking(GCC), and the Sequential Probability Ratio Test(SPRT) method in a decision estimator module. The GCC method is a computationally efficient system for redundant sensors, while the SPRT provides the ability to make decisions based on the degradation history of a sensor. The methodology is also extended to the detection of noise degradation. The acceptability of the proposed method is demonstration by using the simulation data in safety injection accident of nuclear power plants. The results show that the signal validation and sensor failure detection system is able to detect and isolate a bias failure and noise type failures under transient conditions. And also, the system is able to provide the validated signal by reconstructing the measurement signals in the failure conditions considered.

• Journal of Institute of Control, Robotics and Systems
• /
• v.20 no.6
• /
• pp.689-694
• /
• 2014

An SPLC (Safety Programmable Logic Controller) must be designed to meet the highest safety standards, IEEE 1E, and should guarantee a level of fault-tolerance and high-reliability that ensures complete error-free operation. In order to satisfy these criteria, I/O modules, communication modules, processor modules and bus modules of the SPLC have been configured in triple or dual modular redundancy. The redundant modules receive the same data to determine the final data by the voting logic. Currently, the processor of each rx module performs the voting by deciding on the final data. It is the intent of this paper to prove the improvement on the current system, and develop a voting system for multiple data on a system bus level. The new system bus protocol is implemented based on a TCN-MVB that is a deterministic network consisting of a master-slave structure. The test result shows that the suggested system is better than the present system in view of its high utilization and improved performance of data exchange and voting.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2010.11a
• /
• pp.852-854
• /
• 2010

MCM-ERC32 는 우주 환경에서 동작하는 시스템에 사용할 목적으로 유럽에서 개발된 집약 프로세서 모듈이다. MCM (Multi Chip Module)은 크게 ERC32 single chip 과 VASI (Very Advanced Sparc Interface) 및 6MByte 의 SRAM, 32MByte 의 DRAM 으로 구성되어 있다. VASI 의 경우 각종 I/O 처리 및 timer 의 기능을 수행하며 특히 VASI RTC 의 경우 VASI cycle, slot 을 이용하여 다양한 형태의 timer 구현이 가능하다. Timer 의 경우 각종 태스크의 관리와 스케줄링에 사용되는 가장 기본적이며 매우 중요한 요소이다. 위성의 고유 시간 역시 timer 를 활용하여 설계하게 되는데 이 부분이 잘 구현 되어야 정확한 임무 수행 및 위성의 제어가 가능하다. 본 논문에서는 VASI RTC 의 구조와 기능에 대해 설명하고 이를 위성의 고유 시간 운영에 적용하는 방법에 대해 다루도록 하겠다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2001.04b
• /
• pp.727-730
• /
• 2001

초고속 인터넷 서비스의 확대에 따라 이를 교육에 직 간접적으로 응용하기 위한 노력이 지속적으로 진행되어 왔다. 특히 웹 기반의 가상강의 저작도구를 통한 웹 코스웨어는 원거리 학습자들의 학습 욕구를 자기 주도적인 학습을 통해 가능케 했고 기존의 텍스트, 사운드를 통한 가상강의에서 동영상이 가미된 주문형 교육 서비스(EOD: Education On Demand)가 가능해졌다. 그러나 이를 이용하는 학습자는 전체적인 모듈의 이해를 통해 수업이 진행됨에 따라 학습과정에서는 질의응답을 튜터를 통해 웹 캐스팅이 이루어졌다. 따라서, 질의응답은 텍스트 형식의 E-mail, 채팅, 게시판, 방명록을 통해 이루어지므로 학습자가 요구한 질의 내용을 잘못 이해하고 튜터가 학습 과정에서의 피드백을 제공하지 못함으로써 개인 학습의 동기부여가 감소됨에 따라 흥미를 잃게 되었다. 본 논문에서는 이러한 문제점을 개선하기 위해 멀티 캐스팅 기법을 통해 교육용 서버를 이용한 학습지원도구를 분석, 설계한다. 가상강의는 기본적인 컨텐츠를 제시하고 그를 통해 수업이 진행되는 과정에서의 질의응답을 일대다(One-To-Many)의 멀티 캐스팅 서비스를 튜터가 지정한 교육용 서버를 통해 텍스트 형식이 아닌 강의자료로 쓰인 문서 파일에 직접 작성하여 전송하게 된다. 따라서 튜터는 메일링 서비스를 통해 질문사항을 자신의 폴더 서비스로 확인하고 즉시 학습자에게 피드백을 제공함으로써 튜터와 학습자들간의 커뮤니케이션이 활발히 이루어지며, 상호작용의 증가를 통해 웹 기반의 컨퍼런싱(WBC: Web Based Conferencing)을 가질 수 있게 된다.rver는 Client가 요청한 Content(services)를 전달 해 주는 컨텐트 전달 모듈(Content Deliver Module)과 서버 Phonebook 엑세스 모들(Server Phonebook Access Module)로 구성되어 있다.외 보다 높았다(I/O ratio 2.5). BTEX의 상대적 함량도 실내가 실외보다 높아 실내에도 발생원이 있음을 암시하고 있다. 자료 분석결과 유치원 실내의 벤젠은 실외로부터 유입되고 있었고, 톨루엔, 에틸벤젠, 크실렌은 실외뿐 아니라 실내에서도 발생하고 있었다. 정량한 8개 화합물 각각과 총 휘발성 유기화합물의 스피어만 상관계수는 벤젠을 제외하고는 모두 유의하였다. 이중 톨루엔과 크실렌은 총 휘발성 유기화합물과 좋은 상관성 (톨루엔 0.76, 크실렌, 0.87)을 나타내었다. 이 연구는 톨루엔과 크실렌이 총 휘발성 유기화합물의 좋은 지표를 사용될 있고, 톨루엔, 에틸벤젠, 크실렌 등 많은 휘발성 유기화합물의 발생원은 실외뿐 아니라 실내에도 있음을 나타내고 있다.>10)의 $[^{18}F]F_2$를 얻었다. 결론: $^{18}O(p,n)^{18}F$ 핵반응을 이용하여 친전자성 방사성동위원소 $[^{18}F]F_2$를 생산하였다. 표적 챔버는 알루미늄으로 제작하였으며 본 연구에서 연구된 $[^{18}F]F_2$가스는 친핵성 치환반응으로 방사성동위원소를 도입하기 어려운 다양한 방사성의 약품개발에 유용하게 이용될 수 있을 것이다.었으나 움직임 보정 후 영상을 이용하여 비교한 경우, 결합능 변화

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.22 no.12
• /
• pp.2674-2685
• /
• 1997

In this paper, the design and imprlementation of dual-band power amplifier which is used as a critical part for mobile phone to be simultaneously working at a dual band, 800MHz CDAM and PCS frequency band is described. DC operating point of power FET is limited to Class-B to enable long talk time considering that the tyupical power range of CDMA phones in working is around 10 to Class-B to enable long talk time considering that the typical power range of CDMA phones in working is around 10 to 15dBm, i.e., liner range. The power amplifier which employs two GaAs FETs with good linerity at a low operating point has duplexer cuplexer circuit to separate two frequency bands at input and output stage. Electromagnetic analysis for via holes and coupling between narrow transmission lines is included to design a circuit. Moduld size of 0.96CC($22{\times}14.5{\times}3mm^3$) and maximum module current of 130mA at output power range, 10 to 15dBm are attained. The power amplifer module has achieved ACPR performance with 2 to 3dB marging from IS-95 requirement at output powers, 23.5dBm for PCS and 28dBm for 800MHz CDMA respectively.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.10 no.4
• /
• pp.659-666
• /
• 2006

Servo-motors are used as key components of automated system by performing precise motion control as accurate positioning and accurate speed regulation in response to the commands from computers and sensors. Especially, the linear brushless servo-motors have numerous advantages over the rotary servo motors which have connection with the friction induced transfer mechanism such as ball screws, timing belts, rack/pinion. This paper proposes an estimation method of unknown motor system parameters using the informations from the sinusoidal driving type linear brushless DC motor dynamics and outputs. The estimated parameters can be used to tune the controller gain and a disturbance observer. In order to meet this purpose high performance Digital Signal Processor, TMS320F240, designed originally for implementation of a Field Oriented Control(FOC) technology is adopted as a controller of the liner BLDC servo motor. Having A/D converters, PWM generators, rich I/O port internally, this servo motor application specific DSP play an important role in servo motor controller. This linear BLDC servo motor system also contains IPM(Intelligent Power Module) driver and hail sensor type current sensor module, photocoupler module for isolation of gate signals and fault signals.

• The KIPS Transactions:PartA
• /
• v.19A no.1
• /
• pp.35-44
• /
• 2012

Traditional technologies that are used to improve the performance of hard disk drives show many negative cases if they are applied to solid state drives (SSD). Access time and block sequence in hard disk drives that consist of mechanical components are very important performance factors. Meanwhile, SSD provides superior random read performance that is not affected by block address sequence due to the characteristics of flash memory. Practically, it is recommended to disable prefetching if a SSD is installed in a personal computer. However, this paper presents a combinational method of a prefetching scheme and a memory management that consider the internal structure of SSD and the characteristics of NAND flash memory. It is important that SSD must concurrently operate multiple flash memory chips. The I/O unit size of NAND flash memory tends to increase and it exceeded the block size of operating systems. Hence, the proposed prefetching scheme performs in an operating unit of SSD. To complement a weak point of the prefetching scheme, the proposed memory management scheme adaptively evicts uselessly prefetched data to maximize the sum of cache hit rate and prefetch hit rate. We implemented the proposed schemes as a Linux kernel module and evaluated them using a commercial SSD. The schemes improved the I/O performance up to 26% in a given experiment.

• Proceedings of the KIEE Conference
• /
• 2004.07c
• /
• pp.1745-1747
• /
• 2004

In order to anticipate gradual increase of fault current in electric power systems, current limiting technology and current limiting device has been investigated for a long time. But the commercial use of current limiting device was delayed due to the lack of effective method to insert impedance to the elective power systems without loss and surplus defects. However, novel current limiting device, which use superconducting materials, was considered as a dream technology to be applied in a distribution and transmission lines. LG Industrial systems and KERPI started to investigate resistive type superconducting fault current limiters in order to develop 154kV fault current limiters and this year, we succeed to test 3 phase 6.6kV/200A fault current limiters. Based on these achievements, 24kV superconducting fault current limiters will be realized withing 3 years which could be tested in a real fields. In this paper, the developments of fault current limiting module which use YBCO thin films, cryogenic systems, the structure and construction of 3 phase fault current limiters and finally the test results of 6.6kV superconducting fault current limiters will be introduced.

• Journal of Korea Multimedia Society
• /
• v.8 no.11
• /
• pp.1472-1482
• /
• 2005

In this paper, we propose a socket interface layer for large-scale multimedia servers that adopt TCP/IP Offload Engines (TOE). In order to provide legacy network applications with binary level compatibility, the socket interface layer intercepts all socket-related system calls to forward to either TOE or legacy TCP/IP Protocol stack. The layer is designed and implemented as a kernel module in Linux. The layer is located between BSD socket layer and INET socket layer, and passes the application's socket requests to INET socket layer or TOE. The layer provides multimedia servers and web servers with the following features: (1) All standard socket APIs and file I/O APIs that are supported (2) Support for binary level compatibility of existing socket programs (3) Support for TOE and legacy Ethernet NICs at the same time.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.12 no.1
• /
• pp.75-84
• /
• 2017

It becomes more and more more important for the storage that supports high speed recording and stable access from network environment. As one field of basic science which produces massive astronomical data, VLBI(: Very Long Baseline Interferometer) is now demanding more data writing performance and which is directly related to astronomical observation with high resolution and sensitivity. But most of existing storage are cloud model based for the high throughput of general IT, finance, and administrative service, and therefore it not the best choice for recording of big stream data. Therefore, in this study, we design storage system optimized for high performance of I/O and concurrency. To solve this problem, we implement packet read and writing module through the use of libpcap and pf_ring API on the multi core CPU environment, and build a scalable storage based on software RAID(: Redundant Array of Inexpensive Disks) for the efficient process of incoming data from external network.