• Journal of information and communication convergence engineering
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• v.14 no.2
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• pp.89-96
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• 2016

In mobile communication, there are various types of handoff for the support of all forms of mobility. Proxy mobile IPv6 (PMIPv6) enables local network-based mobility management of a mobile node without any effect of mobility-related signaling. Recently, PMIPv6 has been considered for supporting mobility management in LTE/SAE-based mobile networks. To support seamless mobility in heterogeneous mobile networks, the overall cost of handoffs needs to be minimized and the procedure should be guaranteed to be secure. However, the reduction of the authentication cost has not been fully investigated to provide seamless connectivity when mobile users perform a handoff between the PMIPv6 domains. This paper proposes secure pre-authentication schemes, completing an authentication procedure before performing a handoff, for a fast handoff in PMIPv6. Analytic models have been used for measuring the authentication latency and for the overhead cost analysis. In addition to providing fast authentication, the proposed pre-authentication schemes can prevent threats such as replay attacks and key exposure.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.136-139
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• 2005

On-line dynamic security assessment is becoming more and more important for the stable operation of power systems as load level increases. The necessity is getting apparent under Electricity Market environments due to more various operating conditions. Fast transient stability analysis tool is required for contingency selection. The TEF(Transient Energy Function) method is a good candidate for this purpose. The clustering of critical generators is crucial for the precise and fast calculation of energy margin. In this paper, we propose a new method for fast decision of mode of instability by using stability indices. Case study shows very promising results.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.159-164
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• 2004

Recently the unexpected damage is broken out by the unusal change of weather. Misfortune on top of misfortune the typhoon did great damage again before finishing the repair work. And then we should study about the repair work of fast and safety as well as the construction of safety. The paper suggests the case study of a fast disaster restoration work. To minimise the term of repair work which selects Fast Track Method. This work is processed as follows. Temporary resortation is progressed at the same time as the main resortation. And In this paper, technique to evaluate the capacity of bridge is tried to develop by means of FEM analysis.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.423-433
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• 2002

A very fast method of moments(MoM) for the analysis of microstrip structure is considered based upon the use of rooftop basis and razor test functions in conjunction with a new closed-form Green's functions. The present method presents a robust approach to obtain the Green's functions which can be derived by use of only one set of approximation parameters independently of operating frequency range. Moreover, using the present MoM scheme, the MoM matrix elements can be analytically evaluated with few number of terms in comparison with the previous method. So, the computational efficiency can be improved significantly without loss of the precision. In order to check the validity of the present method, performance is demonstrated for the example of a coaxially-fed microstrip transmission line and the present results are compared with the previous results.

• IEIE Transactions on Smart Processing and Computing
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• v.3 no.6
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• pp.388-392
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• 2014

This paper proposes an early termination method of a block vector search for fast encoding of high efficiency video coding (HEVC) screen content coding (SCC). In the proposed algorithm, two blocks indicated by two block vector predictors (BVPs) were first employed as an intra block copy (IBC) search. If the sum of absolute difference (SAD) value of the block is less than a threshold defined empirically, an IBC BV search is terminated early. The initial threshold for early termination is derived by statistical analysis and it can be modified adaptively based on a quantization parameter (QP). The proposed algorithm is evaluated on SCM-2.0 under all intra (AI) coding configurations. Experimental results show that the proposed algorithm reduces IBC BV search time by 29.23% on average while the average BD-rate loss is 0.41% under the HEVC SCC common test conditions (CTC).

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.7
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• pp.1123-1128
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• 2008

The necessity of online dynamic security assessment is getting apparent under Electricity Market environments, as operation of power system is exposed to more various operating conditions. For on-line dynamic security assessment, fast transient stability analysis tool is required for contingency selection. The TEF(Transient Energy Function) method is a good candidate for this purpose. The clustering of critical generators is crucial for the precise and fast calculation of energy margin. In this paper, we propose a new method for fast decision of mode of instability by using stability indices and energy margin. The method is a new version of our previous paper.[1] Case studies are showing very promising results.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.9
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• pp.4487-4511
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• 2018

A fast image encryption system based on substitution and diffusion was proposed, which includes one covering process, one substitution process and two diffusion processes. At first, Chen's chaotic system together with an external 256-bit long secret key was used to generate the key streams for image encryption, in which the initial values of Chen's chaotic system were regarded as the public key. Then the plain image was masked by the covering process. After that the resulting image was substituted with the disturbed S-Box of AES. Finally, the substituted image was diffused twice with the add-modulo operations as the core to obtain the cipher image. Simulation analysis and comparison results with AES and some existing image cryptosystems show that the proposed image cryptosystem possesses the merits of fast encryption/decryption speed, good statistical characteristics, strong sensitivity and etc., and can be used as a candidate system of network security communication.

• Smart Structures and Systems
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• v.18 no.1
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• pp.183-196
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• 2016

In this paper a nonlinear, bistable, single degree of freedom system is considered. It consists of a Duffing oscillator externally excited by a non-resonant, harmonic force. A customized perturbation scheme is proposed to achieve an approximate expression for periodic solutions. It is based on the evaluation of the quasi-steady (slow) solution, and then on a variable change followed by two perturbation steps which aim to capture the fast, decaying contribution of the response. The reconstructed solution, given by the sum of the slow and fast contributions, is in a good agreement with the one obtained by numerical integration.

• Nuclear Engineering and Technology
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• v.42 no.5
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• pp.520-545
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• 2010

This paper presents the neutronics modeling capabilities of the fast reactor simulation system SHARP, which ANL is developing as part of the U.S. DOE's NEAMS program. We discuss the three transport solvers (PN2ND, SN2ND, and MOCFE) implemented in the UNIC code along with the multigroup cross section generation code $MC^2$-3. We describe the solution methods and modeling capabilities, and discuss the improvement needs for each solver, focusing on massively parallel computation. We present the performance test results against various benchmark problems and ZPR-6 and ZPPR critical experiments. We also discuss weak and strong scalability results for the SN2ND solver on the ZPR-6 critical assembly benchmarks.

• ETRI Journal
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• v.32 no.1
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• pp.163-165
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• 2010

A trend in 3D mesh compression is codec design with low computational complexity which preserves the input vertex and face order. However, this added information increases the complexity. We present a fast 3D mesh compression method that compresses the redundant shared vertex information between neighboring faces using simple first-order differential coding followed by fast entropy coding with a fixed length prefix. Our algorithm is feasible for low complexity designs and maintains the order, which is now part of the MPEG-4 scalable complexity 3D mesh compression standard. The proposed algorithm is 30 times faster than MPEG-4 3D mesh coding extension.