• The KIPS Transactions:PartC
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• v.10C no.4
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• pp.405-412
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• 2003

As the XML is approved standard language by the UN, the progress which complemented the XML security has being processed rapidly. In this paper, we design and implement the "XML-Signcryption" as a security mechanism to protect the XML document that can operate between other platforms. The signature and encryption which is the standard specification in W3C needs to be able to proceed them separately. Generally the signature and encryption require four times modular exponential operation, however the signcryption only needed three times modular exponential operation. This will benefit overall system effectiveness in terms of cost. And this scheme offers to convenient the user, because the signature and encryption implement as a single XML format. This tool can save the parsing time as a number of tags is few within a document. And also, in this paper, based on a research of Web Services security, we can apply XML-Signcryption to the SOAP message to provide the security services. Based on the XML-Signcryption scheme which provides confidentiality, integrity, authentication and non-repudiation to the XML document and Web Service security simultaneously.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.5
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• pp.189-193
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• 2008

Digital Contents Services based on Internet are developing into an ubiquitous television that allows subscribers to be able to enjoy digital contents anytime and anywhere However, illegal copies and distributions of digital contents are also increasing proportionally. To guarantee the stability of contents service, many technologies are being developed and installed. The efficient scheme to manage content encryption keys is one of them. In this paper, we propose an improved key management scheme to manage the members of groups. The proposed scheme has a minimized transmission overhead for batch operation to renew content encryption keys.

• Nuclear Engineering and Technology
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• v.54 no.7
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• pp.2435-2443
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• 2022

The once-through steam generator used in the small modular reactor needs to consider the stability of the outlet steam pressure and steam superheat of the secondary circuit to achieve better operating efficiency. For this reason, this paper designs a controllable operation scheme for the steam pressure and superheat of the small reactor once-through steam generator. On this basis, designs a variable universe fuzzy controller, first, design the fuzzy control rules to make the controller adjust the PI controller parameters according to the change of the error; secondly, use the domain adjustment factor to further subdivide the input and output domain of the fuzzy controller according to the change of the error, to improve the system control performance. The simulation results show that the operation scheme proposed in this paper have better system performance than the original scheme of the small reactor system, and controller proposed in this paper have better control performance than traditional PI controller and fuzzy PI controller, what's more, the designed control system also showed better anti-disturbance performance in lifting experiment between 100% and 80% working conditions. Finally, the experimental platform formed by connecting the digital small reactor with Matlab/Simulink through OPC(OLE for Process Control) communication technology also verified the feasibility of the proposed scheme.

• Water Engineering Research
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• v.3 no.1
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• pp.57-62
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• 2002

This research is intended to integrate long-term operation rules and real time operation policy for conservation & flood control in a reservoir. The familiar Yield model has been modified and used to provide long-term rule curves. The model employs linear programming technique under given physical conditions, i.e., total capacity, dead storage, spillways, outlet capacity and their respective elevations to find required and desired minimum storage fur different demands. To investigate the system behavior resulting from the above-mentioned operating policy, i.e., the rule curves, the simulation model was used. Results of the simulation model show that the results of the optimization model are indeed valid. After confirmation of the above mentioned rule curves by the simulation models, gate operation procedure was merged with the long term operation rules to determine the optimum reservoir operating policy. In the gate operation procedure, operating policy in downstream flood plain, i.e., determination of damaging and non-damaging discharges in flood plain, peak floods, which could be routed by reservoir, are determined. Also outflow hydrograph and variations of water surface levels for two known hydrographs are determined. To examine efficiency of the above-mentioned models and their ability in determining the optimum operation policy, Esteghlal reservoir in Iran was analyzed as a case study. A numerical model fur the solution of two-dimensional dam break problems using fractional step method is developed on unstructured grid. The model is based on second-order Weighted Averaged Flux(WAF) scheme with HLLC approximate Riemann solver. To control the nonphysical oscillations associated with second-order accuracy, TVD scheme with SUPERBEE limiter is used. The developed model is verified by comparing the computational solutions with analytic solutions in idealized test cases. Very good agreements have been achieved in the verifications.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.859-862
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• 1998

An offset compensation scheme for rail-to-rail CMOS op-amps with complementary input stages is presented. Two auxiliary amplifiers are used to compensate for the offsets of NMOS and PMOS differnetial input stages, and ping-pong control is employed for continuous-time operation. Simulation and measurements resutls show that offsets are reduced about 20 times by this scheme.

• Journal of Communications and Networks
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• v.7 no.3
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• pp.278-283
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• 2005

This paper proposes a blind channel estimation scheme for long code direct sequence code division multiple access (DS­CDMA) systems with multipath fading channels. This scheme combines the advantages of Toeplitz displacement and correlation matching methods to achieve improved performance. The basic idea is to remove the effects of noise and interferences with Toeplitz displacement operation and then estimate the multi path channel parameters with the correlation matching method. Simulation results are presented to show that the proposed scheme provides better MSE performance and robustness against the near-far problem.

• Journal of Industrial Technology
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• v.21 no.A
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• pp.65-71
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• 2001

In this paper, we propose handoff scheme for BT(Bluetooth) IP and define signaling for the handoff scheme. In local area, BT IP use the concept of Cellular IP and the operation property of Bluetooth system. In case of accessing external internet, use the concept of Mobile IP. IP-based Mobility of Bluetooth Terminal provides efficient and rapid mobility in local area and flexibility on the internet.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.414-416
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• 2005

In this paper, a new scheme of current programmed control for three phase PWM AC-AC converter is presented. By considering only the magnitude components, a similar scheme in the DC-DC converter can be extended to the three phase PWM AC-AC converter. The proposed current programmed control will be well adopted into various converter topologies though three phase PWM AC-AC boost converter is treated as an example. The converter analysis is carried out by applying the vector DQ transformation to obtain physical insight into the converter operation. Finally, the experiment result shows the validity of the proposed scheme.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.18-21
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• 1998

A stabilization scheme of a missile actuator using fuzzy controller is proposed. A variable-reluctance stepping motor adopted as a actuator is critically restricted useful operation since pronounced oscillatory behaviour at a certain input frequencies. The previous stabilization scheme. which employs frequency modulation, of the clock-pulse source using derived from the modulation envelope of the total intake current is modified using fuzzy control. The proposed scheme has apparent advantage, particularly in size, mass and flexibility.

• Journal of Korean Institute of Industrial Engineers
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• v.24 no.4
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• pp.519-528
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• 1998

This paper examines the effect of storage location configurations on dual command cycle times for the efficient operation of automated storage/retrieval systems. We use a contour line approach to determine storage location configurations. We present a contour line configuration generating scheme and a location indexing scheme. Given a contour line configuration, the location indexing scheme provides a unique priority to each location. The location priority is then used for determining the storage location of an incoming load. To investigate the effect of alternative contour line configurations on dual command cycle times, we perform a series of experiments under various storage policies.