• Aerospace Engineering and Technology
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• v.13 no.2
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• pp.73-79
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• 2014

During developing cubesat flight software, Communication test between cubesat and ground station is needed. For this, we have constructed indoor ground station without outdoor antenna for decreasing total cost and time. In this time, if output power of ground station is high, it will affect for cubesat transceiver to be fail. For solving this problem, ground station must be designed for output power of it to be lower than input power of cubesat satellite, and it must be verified. In this paper, first, we describe cubesat indoor ground station using UHF and VHF. Second, we describe output power decreasing test for indoor operation of ground station by attaching attenuators in the end of the output connector.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.6
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• pp.39-46
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• 2003

In this papers, We studied system requirement specification, hardware design and implementation, protective algorithm and software design method to implement digital protective relay which has high trust and high function of protection as well as control and metering for power transformers. Protective relay for transformer is implemented on real time using DSP, which is the specific processor for digital signal processing, as a result, it is completed by the wide improvement of arithmetic capability of protective relay. Reliability is proved testing operating value and operating time, reset value and reset time of an relaying element using protective relay tester made in NF Corporation of Japan.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2741-2749
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• 2009

There have been many researches to detect and recover from faults on smart home environment, because these faults should lower its reliability. while, most of these researches have addressed functional defects of devices or software malfunction, few attempts have been made to deal with faults which may occur due to the inter relationships among devices. In this paper, we define the relationships among devices as rules, and propose a method for generating fault diagnosis knowledge which defines the symptoms and causes of faults. We classify the contexts of devices into two sets, depending on whether it satisfies the rules or not. when this method is applied to smart home environment, it is feasible not only to detect faults that may occur due to the relationships among devices but to identify their causes at real time.

• KSCI Review
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• v.14 no.2
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• pp.129-134
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• 2006

In this paper, we designed and implemented DCS terminal remote monitoring middleware for real-time auditor and management terminal status signal with relay and fuse status at power management room. The middleware consist of four component as event analyzer, event manager, service manager and user interface. We expected economic effects extend relay life-time that pre-detected errors and prevented relay fault.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.13 no.2
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• pp.160-170
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• 1988

This paper describes the outboard NIU(Network Interface Unit) using microprocessor and the hardware and software of concentrator for constructing star typed LAN(Local Area Network) based on token ring method. The NIU adapter can adapter up to four parallel and serial typed terminals. Because it has PAD function on input output data, any type of terminals can be adapted. Since the concentrator has logical switching circuit which enables data to bypass the faulted NIU adapter, this network prevents communication break. When user transmits and receives data, the concentrator constructs star typed LAN which connct both transmitting and receiving sides. A s result, this network eliminated ring latency time in other NIU exculding transmitting and receiving NIU. So the throughput of this LAN is increased. Because this LAN system consists of several modultes according to it's function, the expansion of function or the modification of method is easy.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.4
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• pp.163-168
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• 2002

This paper present a new verb efficient numerical algorithm for arcing faults detection and fault distance estimation in transmission line. It is based on the fundamental differential equations describing the transients on a transmission line before, during and alter the fault occurrence, and on the application of the "Least Error Squares Technique"for the unknown model parameter estimation. If the arc voltage estimated is a near zero, the fault is without arc, in other words the fault is permanent fault. If the arc voltage estimated has any high value, the faust is identified as an fault, or the transient fault. In permanent faults case, fault distance estimation is necessary. This paper uses the model of the arcing fault in transmission line using ZnO arrestor and resistance to be implemented within EMTP. One purpose of this study is to build a structure for modeling of arcing fault detection and fault distance estimation algorithm using Matlab programming. In this paper, This algorithm has been designed in Graphic user interface(GUI).

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.8
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• pp.18-24
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• 2011

A new problem happens with the evolution of TSV based 3D IC design. The bonding process takes place which follows with the testing of design for proper connectivity in the absence of TSV redundancy. In order to achieve good yield, the design should be tested with redundancy TSV. This paper presents a wrapper cell design for redundancy TSV interconnect test. The design for test technique, in terms of hardware and software perspectives is described. The wrapper cell with hardware design can use original test patterns. However, software design has less area overhead.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.3
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• pp.1-9
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• 2014

The inverse Rayleigh model distribution and Rayleigh distribution model were widely used in the field of reliability station. In this paper applied using the finite failure NHPP models in order to growth model. In other words, a large change in the course of the software is modified, and the occurrence of defects is almost inevitable reality. Finite failure NHPP software reliability models can have, in the literature, exhibit either constant, monotonic increasing or monotonic decreasing failure occurrence rates per fault. In this paper, proposes the inverse Rayleigh and Rayleigh software reliability growth model, which made out efficiency application for software reliability. Algorithm to estimate the parameters used to maximum likelihood estimator and bisection method, model selection based on mean square error (MSE) and coefficient of determination($R^2$), for the sake of efficient model, were employed. In order to insurance for the reliability of data, Laplace trend test was employed. In many aspects, Rayleigh distribution model is more efficient than the reverse-Rayleigh distribution model was proved. From this paper, software developers have to consider the growth model by prior knowledge of the software to identify failure modes which can helped.

• Journal of KIISE:Software and Applications
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• v.26 no.4
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• pp.462-472
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• 1999

능동적 시간지원 데이터베이스 시스템은 시간지원 데이터베이스 시스템에 능동규칙 시스템을 통합하여 구성한 진보된 데이터베이스 시스템이다. 이 시스템은 추세 분석, 상태 관찰을 통한 경보,고장에 대한 예측, 금융 시스템 및 공정 제어 등과같은 고도의 응용에 효과적으로 대응할수 있다. 그러나 능동적 시간지원 데이터베이스 시스템은 시간 차원을 갖는 다차원 데이터공간에 대해 처리해야 하므로 그 처리비용이 매우 높으며, 규칙 처리에 의한 시스템 부하가 매우 증가할 수 있다. 따라서 효과적 규칙 처리방법에 대한 연구가 수행되어야 한다. 한편 규칙의 성능에 대한 문제는 일반적으로 조건 평가 방법의 효율성에 달려있다. 특히 데이터의 시간차원을 고려한 시간지원 능동규칙의 경우 시간 영역에 따라 규칙에 의해 처리되어야 할 데이터 량의 증가하고 이에 다라 성능의 차이가 많이 나므로 더욱 문제가 된다. 따라서 이 논문에서는 능동적 시간지원 데이터베이스 시스템을 위한 시간지원 능동규칙의 성능향상을 위해 조건 평가를 검토하고 시간지원 차분에 의한 시간지원 점진적 평가연산을 제시하였다. 아울러 이 시간지원 점진적 연산자를 적용한 조건 평가 예를 보이고 이 연산자의 효율성을 증명하였다.

• Journal of Information Technology Applications and Management
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• v.24 no.1
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• pp.25-32
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• 2017

For repairable software systems, the Mean Time Between Failure (MTBF) is used as a measure of software system stability. Therefore, the evaluation of software reliability requirements or reliability characteristics can be applied MTBF. In this paper, we want to compare MTBF in terms of parameter estimation using Makeham life distribution. The parameter estimates used the least square method which is regression analyzer method and the maximum likelihood method. As a result, the MTBF using the least square method shows a non-decreased pattern and case of the maximum likelihood method shows a non-increased form as the failure time increases. In comparison with the observed MTBF, MTBF using the maximum likelihood estimation is smallerd about difference of interval than the least square estimation which is regression analyzer method. Thus, In terms of MTBF, the maximum likelihood estimation has efficient than the regression analyzer method. In terms of coefficient of determination, the mean square error and mean error of prediction, the maximum likelihood method can be judged as an efficient method.