• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.11
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• pp.6845-6848
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• 2014

This paper proposes a system design of IDS for detecting and defending against DDoS attacks on a network. The proposed system has three parts; the Alert, Attack Analyzer and Defense agent. When the server resource was reduced too much by incoming traffic, the Alert Agent sends message and traffic information to the Attack Analyzer. The message and traffic to the Attack analyzer include only the sender & receiver address and packet numbers for minimizing the overload of Attack Analyzer. Message Received Attack Analyzer investigates the Message. If the pattern of traffic is the same as the DDoS Style, the Analyzer sends a message to the Defense Agent to block that traffic. In this system, at the serious state of the server-down, the Attack analyzer uncovers the DDoS Attacker and send a message to the Defense Agent to block that traffic. This works for server reactivation as soon as possible.

• International Journal of Automotive Technology
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• v.7 no.4
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• pp.385-390
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• 2006

A fast response $CO_2$ analyzer has been developed to study transient characteristics on an SI engine. The analyzer has the delay time of 4.5 ms and time constant of 2.8 ms, which is fast enough to measure $CO_2$ concentration on a transient condition. Wide range of A/F(Air/Fuel) ratio can be estimated using the analyzer with an additional switch type oxygen sensor. The results of measurement of $CO_2$ concentration and A/F ratio on a transient condition including rapid acceleration/deceleration and EGR(Ehxaust Gas Recirculation) on/off are presented and compared with a commercial exhaust gas analyzer and UEGO(Universial Exhaust Gas Oxyzen) sensor.

• Journal of Electrical Engineering and Technology
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• v.6 no.4
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• pp.573-579
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• 2011

To meet the scalability and performance requirements of data analyses, which often involve voluminous data, efficient parallel or concurrent algorithms and frameworks are essential. We present a high-performance Korean morphological analyzer which employs the MapReduce framework on the graphics processing unit (GPU). MapReduce is a programming framework introduced by Google to aid the development of web search applications on a large number of central processing units (CPUs). GPUs are designed as a special-purpose co-processor. Their programming interfaces are typically formulated for graphics applications. Compared to CPUs, GPUs have greater computation power and memory bandwidth; however, GPUs are more difficult to program because of the design of their architectures. The performance of the Korean morphological analyzer using the MapReduce framework on the GPU is evaluated in comparison with the CPU-based model. The proposed Korean Morphological analyzer shows promising scalable performance on distributed computing with the GPU.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.1015-1018
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• 2003

As increasing the size and complexity of hard-ware and software system, more efficient design methodology has been developed. Especially design-reuse technique enables fast system development via integrating existing hardware and software. For this technique available hardware/software should be prepared as component-based parts, adaptable to various systems. This paper introduces a component-based VHDL analyzer allowing to be embedded in other applications, such as simulator, synthesis tool, or smart editor. VHDL analyzer parses VHDL description input, and performs lexical, syntactic, semantic checking, and finally generates intermediate-form data as the result. VHDL has full-features of object-oriented language such as data abstraction, inheritance, and polymorphism. To support these features special analysis algorithm and intermediate form is required. This paper summarizes practical issues on implementing high-performance/quality VHDL analyzer and provides its solution that is based on the intensive experience of VHDL analyzer development.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.12
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• pp.994-1000
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• 2001

In this paper, using micro-stereolithography technology, I fabricated a liquid analyzer to measure ion concentration of a solution. Micro-stereolithography is a technology to fabricate 3-dimensional structure by applying laser beam on liquid photo-polymer. This technology makes it possible to do preassemble fabrication without any extra assembling step after the process. So, the liquid analyzer could be fabricated at very low cost with very simple process by micro-stereolithography technology. The liquid analyzer consists of a chamber for containing the solution, a pump using piezoelectric effect of PZT disk, a static mixer and a sensor for measuring ion concentration using Pt electrodes.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.11
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• pp.572-576
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• 2004

Various devices for diagnosing arrester soundness are suggested, and most of them simply measure magnitude of leakage current. However, such kind of devices do not provide detailed information needed for the diagnosis. In this study, we designed and fabricated a new arrester analyzer by means of measuring the magnitude, the phase vs. wave height and the harmonics of total leakage currents. The analyzer is composed of a current detector, an optical linker, and a main device operated by a microprocessor. The main device is connected with leakage current detector optically not to be influenced by electromagnetic interference. The analyzer developed measures only total leakage currents, but analyzes most parameters needed for the arrester diagnostics.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.9
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• pp.547-553
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• 2003

In this paper, we designed the PC-based analyzer of the power spectral density that could estimate the heart rate variability from time series data of R-R interval. The power spectral density estimated that it applied the autoregressive model to the measured electrocardiogram during a short period. Also, the characteristics of the designed analyzer are that it could process of the signal filtering, the generation and recomposition of time series and the feature extraction at the same time. Especially the analyzer reconstructed which applied the lowpass filter of the time series composed by the linear interpolation so as to enhance the signal-to-noise feature. We could estimate the power spectral density that confirmed a variety of power peak with low frequency range and high frequency rang of autonomic nerve by the heart rate variability.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.139-142
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• 2004

As fiber reinforced composite materials are widely used in aircraft, space structures and robot arms, the study on the non-destructive testing methods of the composite materials has become an important research area for improving their reliability and safety. In this paper, the AE signal analyzer with the resonance circuit to extract the specified frequency of the acoustic emission signal were designed and fabricated. The noise levels of the fabricated AE signal analyzer by the disturbance such as impact or mechanical vibration had a very small value comparable to those of the conventional AE signal analyzer. Also, the crack detection capabilities of the fabricated AE signal analyzer under the static and dynamic tensile test were evaluated and compared with the conventional AE signal analyzer.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.488-491
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• 2003

Biochip-based diagnostic technology is an effective, time- and money- saving way. But, biochip analyzer including CCD imaging system has a complete optical system. It is one of reasons that the cost of biochip analyzer is expensive with CCD imaging system. In this paper, We suggested the simple and effective optical system for biochip analyzer with CCD imaging system. It consists of two parts with the same structure but opposite direction. Each part consists of achromatic doublet and meniscus. Suggested optical system has less lenses than existing system and more efficiently.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.6
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• pp.2005-2013
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• 1996

Particle paths and flow fields in a prototype differential mobility analyzer (DMA) were numerically analyzed solving Navier-Stokes equation, electric field equation and particle motion considering viscous drag force, Coulomb force and polarization force. Analytically predicted particle diameters for the prototype DMA are in good agreement with the measured particle diameters within $\pm$1%. And the analytically predicted particle diameters are also in good agreement with numerical results for the prototype DMA.