• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.4
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• pp.425-432
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• 2014

Necessity of compact X-band solid-state weather radar is required to provide weather data, which generate locally in a lot of Korea's mountainous area, rather than tube-type radar. Solid State Power Amplifier (SSPA) for using Dual-polarization method in weather radar is able to obtain desired high output by combining many low output power devices in parallel. Thus, Power combiner applying to high-output power amplifier has disadvantages such as path loss, ballast resistance problem by high frequency and high power, heat release. Therefore, In this paper we demonstrated the excellence of isolation, which is the result from modified Gysel power combiner. As a result, we designed X-band 250W solid state power amplifier with peak power 54dBm, 25% power efficiency for weather radar.

• Journal of Korea Multimedia Society
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• v.5 no.3
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• pp.331-341
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• 2002

Traditional slicing techniques make slices through dependence graph and improve the accuracy of slices. However, traditional slicing techniques require many vertices and edges in order to express a data communication link because they are based on static slicing techniques. Therefore the graph becomes very complicated. We propose the representation of a dynamic system dependence graph so as to process the slicing of a software system that is composed of related programs in order to process certain jobs. We also propose programs on efficient slicing algorithm using relations of relative tables in order to compute dynamic slices of a software system. Using a marking table from results of the proposed algorithm can make dynamic system dependence graph for dynamic slice generation. Tracing this graph can generate final slices. We have illustrated our example with C program environment. Consequently, the efficiency of the proposed dynamic system dependence graph technique is also compared with the dependence graph techniques discussed previously. As the results, this is certifying that the dynamic system dependence graph is more efficient in comparison with system dependence graph.

• Journal of Korea Multimedia Society
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• v.14 no.6
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• pp.824-834
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• 2011

In this study, the method to generate facial animation of SVG format based online character AUtomatically was proposed. The re-targeted character can reproduce the modeling facial movements itself without losing the unique formative properties by modeling abundant facial movements of the character in the existing animation for movie theater through the mathematical calculation and 'retargeting' this to other character of SVG format. The method of retargeting facial movements like this can be applied to the various characters by only one facial data so although non-specialists, even not an animator can create facial animation of character easily and rapidly. The suggested facial movement in this study is nonlinear and an exaggerated motion so it is friendly to the viewers and it is lively. Besides, it is based on the SVG format, so the smooth facial movements can be implemented by less capacity than existing GIF animation.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.11
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• pp.581-588
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• 2007

In Digital Right Management, symmetric cipher is used for content encryption to reduce encryption cost, AES, advanced encryption standard is usually used to multimedia encryption under desktop environment because of its reasonable security level and computation cost. But mobile handheld device often uses slow speed processor and operates under battery-powered environment. Therefore it requires low computation cost and low energy consumption. This paper proposes new stream cipher scheme which combines pseudo random number generator(PRNG) and dynamically generated permutations. Proposed scheme activates PRNG and generates original key streams. Then it generates extended key streams by applying permutation to original sequence. These extended key streams are XORed with plaintext and generate ciphertext. Proposed scheme reduces the usage of PRNG. Therefore this scheme is fast and consumes less energy in comparison with normal stream cipher. Especially, this scheme shows great speed up (almost 2 times) than normal stream cipher scheme in random access.

• Journal of the Korean Society of Safety
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• v.31 no.5
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• pp.177-186
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• 2016

When an event is occurred in a nuclear power plant (NPP), the NPP operator reports it referred by the regulation on reporting and public announcement of accidents and incidents. Some of the events do not need to be reported because they are not included in the reporting criteria of the regulation. However, it is necessary that they should be managed effectively because the accident can be occurred by the recurrence of a lot of them as precursors. Among the events not included in the reporting criteria of the regulation, near miss is the event that is not occurred but can generate a significant consequence. This can provide the cause of the event which does not result an accident. So, it is able to offer insightful knowledges to prevent higher level events about the function and process of NPP. The objective of this study is to analyze the issues of near miss events, prepare the defence against the risk, and improve the management process of NPP. To achieve it, this study performed to analyze the management structure and status of near miss events as well as the accident reporting system of the domestic and foreign regulation bodies. In case of Korea, the status was analyzed by quantitative data, licensee event reports and procedures. Based on these, we could find the causes that near miss events were not managed effectively. Then, systematic alternatives that reflected the perspective of man, technology and organization were drawn.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.9
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• pp.1871-1880
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• 2011

In this paper, a controller for two wheeled inverted pendulum robot, i.e., Segway type robot that is a convenient and easily handled vehicle is designed to have more stable balancing and faster velocity control compared to the conventional method. First, a widely used PID control structure is applied to the two wheeled inverted pendulum robot and proper PID control gains for some specified weights of users are obtained to get accurate balancing and velocity control by use of experimental trial-and-error method. Next, neural network is employed to generate appropriate PID control gains for arbitrarily selected weight. Here the PID gains based on the trial-and-error method are used as training data. Simulation study has been carried out to find that the performance of the designed controller using the neural network is more excellent than the conventional PID controller in terms of faster balancing and velocity control.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.10
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• pp.2237-2246
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• 2010

In this paper, the performance of a RCO-MAC protocol is evaluated using a different traffic model. Data frames are assumed to generate based on an exponential distribution from one source node and then directly to be stored into the input buffer in the source node. System throughput, average access delay and average system delay are used as a performance measure. Performance evaluation is carried out by the computer simulation. Numerical results show that the RCO-MAC scheme offers 18% higher system throughput than the rDCF scheme. In addition, the numerical results show that the RCO-MAC protocol also offers the better average system delay under any traffic load than that by the rDCF scheme, which was not obtained in the previous research due to the saturated traffic model.

• Journal of KIISE:Software and Applications
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• v.29 no.12
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• pp.947-956
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• 2002

It is advantageous to use XML in developing user interfaces, since XML is independent from platforms and languages and it is easy to learn and use. The existing XML-based languages do not adopt formal model, and they are developed in ad hoc manner. Moreover, they provide limited facilities to handle user events, and combine user interface components with internal logics. In this paper, we introduce an extended MVP (EMVP) model, which is extended from MVP (Model-View-Presenter), and XUIML, which is a new XML application based on the EMVP to support user interface. XUIML provides useful methods to build user interface, including methods to describe actions on user events, data flows between objects, and internal logics. The XUIML system provides two style editors - text editor and graphic editor. It also provides two code generators. One generates Java source, and the other generate C# code from XUIML document. The XUIML graphic editor allows users to manipulate XML elements directly, and we can gain high productivity with the graphic editor.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.1
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• pp.13-22
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• 2000

We present a method that enhances the rendering speed of z-buffer algorithm using temporal coherence between two contiguous frames on fixed viewing conditions. Conventional z-buffer algorithm stores depth value for each pixel on a view plane while rendering some polygons, then it determines the visibility of the remaining polygons based on the stored depth values. If we can get color and depth information for some polygons without rendering, it is possible to generate an image by rendering only the remaining ones. In case of high frame rate, we can find the fact that sets of static polygons of the two contiguous frames are almost the same. This temporal coherence enables us to get the color and depth information of static polygons efficiently. Our algorithm stores color and depth information of static polygons and reuses it for generating the next frame. This method can be easily implemented since it does not require complex data structure and modification for conventional z-buffer algorithm. Also it is adequate for hardware implementation.

• Journal of KIISE
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• v.42 no.3
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• pp.320-327
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• 2015

Although service robots in various fields are being commercialized, most of them have problems that depend on explicit commands by users and have difficulty to generate robust reactions of the robot in the unstable condition using insufficient sensor data. To solve these problems, we modeled mirror neuron and theory of mind systems, and applied them to a robot agent to show the usefulness. In order to implement quick and intuitive response of the mirror neuron, the proposed intention-response model utilized behavior selection networks considering external stimuli and a goal, and in order to perform reactions based on the long-term action plan of theory of mind system, we planned behaviors of the sub-goal unit using a hierarchical task network planning, and controled behavior selection network modules. Experiments with various scenarios revealed that appropriate reactions were generated according to external stimuli.