• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.12
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• pp.2968-2974
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• 2015

Method for finding the attractors is the important object to investigate in the linear/additive CA because it is a primary interest in applications like pattern recognition, pattern classification, design of associative memory and query processing etc. But the research has been so far mostly concentrated around linear/additive CA and it is not enough to modelize the complex real life problem. So nonlinear CA is demanded to devise effective models of the problem and solutions around CA model. In this paper we introduce CLT as an upgraded version of RMT and provide the process for finding the attractors and nonreachable states effectively through the CLT.

• Journal of KIISE
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• v.42 no.6
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• pp.691-698
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• 2015

Application launch time is an important performance metric to user experience in desktop and laptop environment, which mostly depends on the performance of secondary storage. Application launch times can be reduced by utilizing solid-state drive (SSD) instead of hard disk drive (HDD). However, considering a cost-performance trade-off, utilizing SSDs as caches for slow HDDs is a practicable alternative in reducing the application launch times. We propose a new SSD caching scheme which migrates data blocks from HDDs to SSDs. Our scheme operates entirely in the file system level and does not require an extra layer for mapping SSD-cached data that is essential in most other schemes. In particular, our scheme does not incur mapping overheads that cause significant burdens on the main memory, CPU, and SSD space for mapping table. Experimental results conducted with 8 popular applications demonstrate our scheme yields 56% of performance gain in application launch, when data blocks along with metadata are migrated.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.9
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• pp.2164-2170
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• 2010

Digital Radio Frequency Memory, ( as DRFM ), is a device with the ability to restore output to the input RF signal in the required time after storing the incoming RF signals. Therefore DRFM is widely used in Jammer, EW Simulator, Target Echo Generator, and so on. This paper proposes its hardware implementation composed with the high frequency part and the digital processing part consisting of RF input/output module and local oscillator module. It is also proposed the replicated signal generation method which is consisted of the Analog-Digital conversion in the form of pulsed RF signal quantization, and FPGA to save and produce the playback signal, and RF signals to produce a Digital-Analog Conversion in the digital processing unit. This proposed scheme applied to test board and confirmed the validity of the proposed scheme through the test results obtained by the simulated input signals.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.4
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• pp.671-678
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• 2017

Recent advances in Internet of Things (IoT) encourage us to use IoT devices in daily living areas. However, as IoT devices are being ubiquitously used, concerns onsecurity and privacy of IoT devices are getting grown. Key management is an important and fundamental task to provide security services. For better security, we should restrict reusing a same key in sequential authentication sessions, but it is difficult to manually update and memorize keys. In this paper, we propose a hardware security module(HSM) for automated key management in IoT devices. Our HSM is attached to an IoT device and communicates with the device. It provides an automated, secure key update process without any user intervention. The secure keys provided by our HSM can be used in the user and device authentications for any internet services.

• Journal of Korea Game Society
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• v.13 no.5
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• pp.55-62
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• 2013

Since large terrain data can not be loaded on the GPU or CPU memory at once, out-of-core methods which read necessary part from the secondary storage such as a hard disk are commonly used. However, long delay may occur due to limited bandwidth while loading the data from the hard disk to memory. We propose efficient rendering method of large terrain data, which compresses the data with wavelet technique and save its coefficients in RGBA channel of an image us, then decompresses that in rendering stage. Entire process is performed in GPU using Direct Compute. By reducing the amount of data transfer, performing wavelet computations in parallel and doing decompression quickly on the GPU, our method can reduce rendering time effectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.7 no.4
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• pp.300-309
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• 1996

The electric and magnetic fields radiated by lightning discharges are significantly changeable in amplitude and time, one of the topics concerning electromagnetic compatibility of modern electronic systems is the efficient and economic protection against transient voltages caused by not only by direct but also by nearly lightning strokes. In this paper, in order to obtain the detailed informations about lightning electromagnetic impulse waveforms, the electric and magnetic fields radiated by lightning discharges in the summer of 1995 were measured by a fast electric antenna and a loop-type magnetic field sensor, and their charac- teristics were presented and analyzed. The signals of the electric and magnetic fields were re- corded continuously by a transient digitizer having a resolution of 12 bit and a memory capacity of 5000 point and using a sampling time of 200 ns. The electric and magnetic field waveforms associated with lightning return strokes are significantly different with those of intracloud discharges. The magnetic fields radiated by intracloud lightning discharges have essentially the same waveforms as the electric field when the lightning discharhes are at distance of 50 km or more. Also the main frequency components of the electric and magnetic fields radiated by lightning discharges range from a few kHz to several hundred kHz.

• The KIPS Transactions:PartB
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• v.11B no.3
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• pp.337-344
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• 2004

Most of the virtual space constructed sufficiently realistic need a lot of memory space to navigate smoothly. And this kind of virtual space also requires real-time responsibility for the navigation as well as realism. In the off-line virtual system, real-time responsibility can be resolved by using large scale if secondary memory. In the web-based online virtual system, on the other hand, real-time responsibility is highly related to the latency time of network data communication. This induces the necessity of the algorithm for fast data loading. In this paper, we propose and verify the validity of the two methodology for cell leading algorithm. According to the results of computer simulation, the algorithm using hexagonal type cell promotes the real-time responsibility over 30％ than that of the rectangular type.

• Journal of Korea Game Society
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• v.14 no.4
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• pp.45-52
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• 2014

We cannot load the entire data for high-resolution terrain model to the GPU memory since its size is too big. Out-of-core approaches are commonly used to solve the problem. However, due to limited bandwidth of the secondary storage, it is difficult to render the terrain in real-time. A method that compresses the DEM data with wavelet transform on GPU, and renders the decoded data is suggested. However, it is inefficient since it has to sample the values from textures, convert them to vertices, and generate a mesh periodically. We propose a method to store the approximation coefficients of wavelet compression as vertex attributes and render the terrain by decoding the data on geometric shader. It can reduce the amount of transferring terrain texture since approximation coefficients are given as an attribute of the vertex. Also, it generate meshes without additional upload of terrain texture.

• 한국HCI학회:학술대회논문집
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• 2006.02b
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• pp.403-408
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• 2006

디지털 카메라의 사용이 일반화되면서, 사용자가 사진을 찍고 보관하고 감상하는 행태가 과거의 일반 카메라와 다른 모습을 보이고 있다. 특히 디지털 카메라는 유지비가 거의 들지 않기 때문에 한번에 촬영하는 사진의 양이 많은 반면에 인쇄하여 보관하는 사진의 양은 매우 적은 경향을 보인다. 디지털 사진의 양이 방대하게 늘어나고, 인쇄하기 보다는 저장 장치에 보관하게 됨에 따라서 과거의 앨범에 인쇄된 사진을 보관하고 감상하던 방식과 감상하는 행태도 변화되었다. 디지털 카메라로 찍어서 하드디스크에 저장한 사진들은 각 폴더에 어떤 사진들이 들어 있는지를 기억하기 어렵기 때문에 앨범을 보는 것처럼 자주 감상하지 않게 되는 경향이 관찰되었고, 또 인쇄된 사진을 보고, 그 사진과 연관된 다른 사진들을 보고자 디지털로 저장되어 있는 하드디스크에 접속하는 경향이 관찰되었다. 본 연구에서는 촬영된 디지털 카메라의 사진을 분류하여 보관하고 감상하는 사용자의 행태를 분석하고, 이에 적합한 새로운 디지털 사진 관리 시스템을 제안하고자 한다. 특히, 자연스럽게 앨범을 넘겨보다가 인쇄된 디지털 사진과 관련된 컨텍스트를 갖는 다른 디지털 사진들을 저장 매체에서 바로 찾아서 디스플레이를 통해 감상할 수 있는 새로운 방식의 UI를 제안하였다. 이를 위해 인쇄된 사진에 사진의 컨텍스트 코드를 함께 인쇄하고, 추후에 출력된 사진의 컨텍스트 코드를 해독하여 원본 디지털 사진 및, 동일한 컨텍스트를 가지는 디지털 사진들을 자동으로 찾아서 디스플레이 하는 검색 및 감상 방식을 사용하였다. 이를 통해 디지털 사진을 감상하기 위해 거쳐야 했던 기존의 번거로운 과정을 단축하고 디지털 사진을 분류하여 보관하고 원하는 사진을 방대한 데이터 속에서 찾아야 하는 문제를 줄일 수 있었다.

• The Journal of the Korea Contents Association
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• v.11 no.2
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• pp.135-141
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• 2011

Mobile communication technology in the field of ubiquitous computing is one of important technologies. The development of GPS technology in mobile communications technology and PDA, the vast majority of mobile devices such as smart phones also being equipped with GPS functionality. This user where they are located where they are based on the number of through services were able to receive information. In this paper, mounted on a mobile device user's location using GPS capabilities to track the migration routes and the accumulated user to determine the migratory path of the system used to recommend the proposed route of the proposed method and system Designs. The services offered by tracking the location of the user to move the user to route data to create and upload to the server. Upload a migration path to move data from where they currently reside to the user is recommended to go to your destination. The services offered by the users do not know where to travel or go to your destination, etc. If you do not remember the path can be useful.