• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.11
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• pp.1044-1050
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• 2013

This paper analyzes what is mitigated as spoofing attack using the U-Blox Receiver and GPS RF signal generator developed at ETRI. Generally the spoofing attack made the target receiver to be wrong navigation solution by providing false measurement of code and carrier. So we analyzed the impact of spoofing attack through the signal strength and navigation solution. In oder to test of effect of anti-spoofing signal, we consider the signal with antiphase code to spoofing signal and generated GPS normal signal and spoofing signal and anti-spoofing signal using GPS RF signal generator. This paper analyzed that the GPS receiver was responded to the spoofing attack according to code phase difference between spoofing and anti-spoofing signal. We confirmed that the spoofing signal was disappeared by anti-spoofing signal if code phase is an exact match.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.1
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• pp.175-182
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• 2011

In this paper, we implemented a high-performence memory controller which can accommodate processing blocks(multiple masters) in SoC for video signal processing. The memory controller is arbitrated by the internal arbiter which receives request signals from masters and sends grant and data signals to masters. The designed memory controller consists of Master Selector, Mster Arbiter, Memory Signal Generator, Command Decoder, and memory Signal Generator. It was designed using VHDL, and verified using the memory model of SAMSING Inc. For FPGA synthesis and verification, Quartus II of ATERA Inc. was used. The target device is Cyclone II. For simulation, ModelSim of Cadence Inc was used. Since the designed H/W can be stably operated in 174.28MHz, it satisfies the specification of SDRAM technology.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.246-247
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• 2015

Type of Automatic Voltage Regulator (AVR) can be divided into Analog and Digital Type. Automatic Voltage Regulator (AVR) of the synchronous generators of the brushless type are to be reduced to the voltage fluctuation on the basis of the total load. The PID control method is a general control technique is commonly widely used. In this study, the control target parameter iPID does not reset the parameters of the controller for the variable (Intelligent PID) using the controller synchronous generator Digital automatic voltage to you like all applied to the adjusting device (AVR) the voltage change is small, improved responsiveness was studied in this controller.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.3 s.55
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• pp.63-72
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• 2007

The Emergency Diesel Generator (EDG) is a very important equipment for the safety of a Nuclear Power Plant (NPP). In this study, the operating vibration of three kinds of EDG systems was measured. The target EDG systems are Yonggwang 5 unit and Ulchin 2 and 3 units. The Yonggwang 5 and Ulchin 3 unit EDG systems are the same type but the foundation systems are different. One is an anchor bolt type and the other is a spring and viscous-damper type. The purpose of these measurements is for a verification of the vibration isolation effect depending on the foundation system. As a result, It can be said that the spring and viscous damper system of the EDG performed better for the vibration isolation than that of anchor bolt type.

• Journal of the Korean Institute of Gas
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• v.6 no.1 s.17
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• pp.66-73
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• 2002

In this study a new SIS evaluation method based on the reliability analysis has been developed. It evaluates the Safety Integrity Level (SIL) using the Fault Tree Analysis (FTA), and when the SIL falls short of the systems target level, through the reliability analysis and system retrofit, this method will satisfy the aimed SIL. A hazard evaluation was carried out on the 415V Diesel BUS to verify the SIL evaluation method based on the reliability analysis. The availability of the original 415V Diesel BUS was $99.40\%$, which comes under the category of SIL 2. After exchanging the diesel generator and the isolator switch using the developed evaluation method, the availability rose to $99.94\%$, SIL 3. By applying the method presented in this study, not only will it reduce the maintenance cost due to the prevention of accidents and reduction of loss, but also maximize the reliability of the system.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.5
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• pp.540-548
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• 2012

The Weapon Target Allocation(WTA) problem is the NP-Complete problem. The WTA problem is that the threatful air targets are assigned by weapon of allies for killing the targets. A good solution of NP-complete problem is heuristic algorithms. Genetic algorithms are commonly used heuristic for global optimization, and it is good solution on the diverse problem domain. But there has been very little research done on the generation of their initial population. The initialization of population is one of the GA step, and it decide to initial value of individuals. In this paper, we propose to the population initialization method to improve a Genetic Algorithm. When it initializes population, the proposed algorithm reflects the characteristics of the WTA problem domain, and inherits the dominant gene. In addition, the search space widely spread in the problem space to find efficiently the good quality solution. In this paper, the proposed algorithm to verify performance examine that an analysis of various properties and the experimental results by analyzing the performance compare to other algorithms. The proposed algorithm compared to the other initialization methods and a general genetic algorithm. As a result, the proposed algorithm showed better performance in WTA problem than the other algorithms. In particular, the proposed algorithm is a good way to apply to the variety of situation WTA problem domain, because the proposed algorithm can be applied flexibly to WTA problem by the adjustment of RMI.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.10
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• pp.2237-2246
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• 2012

A bias circuit required for an oral sensor is manufactured inside the oral sensor chip to reduce its size and cost. The proposed DC-DC converter supplies the required reference and bias currents for their corresponding regulators by using IREF of the reference current generator. Their target voltages of the voltage regulators are regulated by the negative mechanism by generating their reference voltages required for their corresponding regulators. In addition, a constant current IB0/IB1 is supplied by being mirrored by a current mirror ratio and then VREF is generated. It is confirmed by measurements that the average volatge, ${\sigma}$, and $4{\sigma}$ of the designed DC-DC converter for intra oral sensors with a $0.18{\mu}m$ X-ray CMOS process are within their required ranges. And the line-pair pattern image shows a high-resolution characteristic without blurring. Also, a good oral image can be obtained.

• Journal of Internet Computing and Services
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• v.7 no.2
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• pp.37-52
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• 2006

A mobile device like ceil phone is the necessity of modern people, of ich con be easily connected to a wireless internet through such a mobile device. The demand for a wireless data communication is growing rapidly. However, agencies have not yet completed standardization of a markup language. Due to the development of the Mobile Device, agencies in this field have provided different data formats with each Mobile Device Platform. Traditionally, contents is hand-tailored to suit the target device. A key problem is that the characteristics and capabilities of the mobile device are too diverse to service the most suitable mobile contents. Because of these problems, the need for a re-usable document description language increases. In this paper, we defined Template file that is common data to service mobile devices. We proposed a method that could be an effective wireless web service though design and the implementation of the Call manager & the XSL Generator. In the methodology, when requesting a wireless internet service, a mobile device finds out markup language and a hardware specification of the mobile device through the Call Manager component supports. The XSL Generator component creates the XSL file dynamically that is the most suitable to a device. Finally, contents is serviced to each device by XSLT. It can generate a wireless page more easily by reusing the existing web contents through such course. Therefore, it can save the time and expense for generating a wireless page.

• Journal of the Korea Society for Simulation
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• v.18 no.3
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• pp.23-34
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• 2009

In the railroad rolling stock depot, long-term maintenance tasks is done regularly every two or four year basis to maintain the functionality of equipments and rolling stock body or for the repair operation of the heavily damaged rolling stocks by fatal accidents. This paper addresses the computer simulation model building for the rolling stock maintenance shop for the CDC(Commuter Diesel Car) and Generator Car planned to be constructed at Daejon Rolling Stock Depot, which will be moved from Yongsan Rolling Stock Depot. We evaluated the processing capacity of two layout design alternatives based on the maintenance process chart through the developed simulation models. The performance measures are the number of processed cars per year, the cycle time, shop utilization, work in process and the average number waiting car for input. The simulation result shows that one design alternative outperforms another design alternative in every aspect and superior design alternative can process total 340 number of trains per year 15% more than the proposed target within the current average cycle time.

• Proceedings of the KSPS conference
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• 1996.02a
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• pp.137-155
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• 1996

The purpose of this paper is to generate a pitch contour which is affected by tile phonetic environment and the number of syllables in each Korean isolated word using a neural network. To do this, we analyzed a set of 513 Korean isolated words, consisting of 1-4 syllables and extracted the pitch contour and the duration of each phoneme in all the words. The total number of phonemes we analyzed is about 3800. After that we approximated the pitch contour with a 1st order polynominal by a regression analysis. We could get the slope, the initial pitch and the duration of each phoneme. We used these 3 parameters as the target pattern of the neural network and let the neural network learn the rule of the variation of the pitch and duration, which was affected by the phonetic environment of each phoneme. We used 7 consecutive phoneme strings as an input pattern for a neural network to make the network learn the effect of phonetic environment around the center phoneme. In the learning phase, we used 3545 items(463 words) as target patterns which contained the phonetic environment of front and rear 3 phonemes and the neural network showed the correctness rate of 98.43%, 98.59%, 97.7% in the estimation of the duration, the slope, the initial pitch. In the recall phase, we tested the performance of tile neural network with 251 items(50 words) which weren't need as learning data and we could get the good correctness rate of 97.34%, 95.45%, 96.3% in the generation of the duration, the slope, and the initial pitch of each phoneme.