• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.5
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• pp.1000-1008
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• 2009

It also increases the competitive power of the nation. With all these merits of electronic documents, there exist threats to the security such as illegal outflow, destroying, loss, distortion, etc. Currently, the techniques to protect the electronic documents against illegal forgery, alteration or removal are not enough. Until now, various security technologies have been developed for electronic documents. However, most of them are limited to prevention of forgery or repudiation. Cryptography for electronic documents is quite heavy that direct cryptography is not in progress. Additionally, key management for encryption/decryption has many difficulties that security has many weak points. Security has inversely proportional to efficiency. It is strongly requested to adopt various cryptography technologies into the electronic document system to offer more efficient and safer services. Therefore, this paper presents some problems in cryptography technologies currently used in the existing electronic document systems, and offer efficient methods to adopt cryptography algorithms to improve and secure the electronic document systems. To validate performance of proposed method compare with the existing cryptographies, critical elements have been compared, and it has been proved that the proposed method gives better results both in security and efficiency.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.875-878
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• 2015

In this paper, we propose an intra prediction hardware architecture with less processing time, computations and reduced hardware area for a high performance HEVC encoder. The proposed intra prediction hardware architecture uses common operation units to reduce computational complexity and uses $4{\times}4$ block unit to reduce hardware area. In order to reduce operation time, common operation unit uses one operation unit to generate predicted pixels and filtered pixels in all prediction modes. Intra prediction hardware architecture introduces the $4{\times}4$ PU design processing to reduce the hardware area and uses intemal registers to support $32{\times}32$ PU processmg. The proposed hardware architecture uses ten common operation units which can reduce execution cycles of intra prediction. The proposed Intra prediction hardware architecture is designed using Verilog HDL(Hardware Description Language), and has a total of 41.5k gates in TSMC $0.13{\mu}m$ CMOS standard cell library. At 150MHz, it can support 4K UHD video encoding at 30fps in real time, and operates at a maximum of 200MHz.

• Geophysics and Geophysical Exploration
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• v.24 no.2
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• pp.35-44
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• 2021

As the execution speed of Python is slower than those of other programming languages (e.g., C, C++, and FORTRAN), Python is not considered to be efficient for writing numerical geodynamic code that requires numerous iterations. Recently, many computational techniques, such as the Just-In-Time (JIT) compiler, have been developed to enhance the calculation speed of Python. Here, we developed two-dimensional (2D) numerical geodynamic code that was optimized for the JIT compiler, based on Python. Our code simulates mantle convection by combining the Particle-In-Cell (PIC) scheme and the finite element method (FEM), which are both commonly used in geodynamic modeling. We benchmarked well-known mantle convection problems to evaluate the reliability of our code, which confirmed that the root mean square velocity and Nusselt number obtained from our numerical modeling were consistent with those of the mantle convection problems. The matrix assembly and PIC processes in our code, when run with the JIT compiler, successfully achieved a speed-up 30× and 258× faster than without the JIT compiler, respectively. Our Python-based FEM-PIC code shows the high potential of Python for geodynamic modeling cases that require complex computations.