• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.10
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• pp.3831-3851
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• 2015

This paper is concerned with the problem of joint resource allocation and user-pairing in virtual MIMO SC-FDMA systems to improve service quality of experience (QoE). No-reference logarithmic model is introduced to quantify service experience for each user and the objective is to maximize sum of all user's mean of score (MOS). We firstly formulate the optimal problem into an S-dimensional (S-D) assignment problem. Then, to solve this problem, the modified Lagrangian relaxation algorithm is deduced to obtain the suboptimal result of joint user-paring and subchannel allocation. The merits of this solution are as follows. First, the gap between its results and the global optimal one can be quantified and controlled by balancing the complexity and accuracy, which merit the other suboptimal algorithms do not have. Secondly, it has the polynomial computational complexity and the worst case complexity is O(3LN³), where L is the maximum iteration time and N is the number of subchannels. Simulations also prove that our proposed algorithm can effectively improve quality of experience and the gap between our proposed and the optimal algorithms can be controlled below 8%.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.1
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• pp.71-81
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• 1997

This paper describes an implementation of Chua's oscillator circuits with five - segment piecewise -linear function. Some bifurcation phenomena and chaotic attractors observed experimentally from the laboratory model and simulated by computer for the model are also presented. The Chua's oscillator circuit is implemented with analog electronic devices. Com¬paring both the observations and simulations, the spectrums are satisfactory.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.6
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• pp.1480-1491
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• 2013

Certificate-based cryptography is a new cryptographic primitive which eliminates the necessity of certificates in the traditional public key cryptography and simultaneously overcomes the inherent key escrow problem suffered in identity-based cryptography. However, to the best of our knowledge, all existed constructions of certificate-based encryption so far have to be based on the bilinear pairings. The pairing calculation is perceived to be expensive compared with normal operations such as modular exponentiations in finite fields. The costly pairing computation prevents it from wide application, especially for the computation limited wireless sensor networks. In order to improve efficiency, we propose a new certificate-based encryption scheme that does not depend on the pairing computation. Based on the decision Diffie-Hellman problem assumption, the scheme's security is proved to be against the chosen ciphertext attack in the random oracle. Performance comparisons show that our scheme outperforms the existing schemes.

• Journal of the Korean Ceramic Society
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• v.35 no.9
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• pp.953-957
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• 1998

The effects of catalysts and reactive conditions on the synthesis of aluminum alkoxides are investigated. HgCl2 and I2 as catalysts are used in the synthesis reaction for comparing to no addtion. The absorption peak in IR spectra according to Al-O-L bond of aluminum isopropoxide and aluminum sec-butoxide appear at near 1030cm-1 and 1060cm-1 respectively regardless of kinds of catalysts. The synthesis yield of alu-minum-isopropoxide was 90% in case of no catalyst addition and increased to all of 95% by addition of HgCl2 and I2 The synthesis yield of aluminum sec-butoxide is increased to 95% by addition of I2 catalyst com-paring to no addition.

• Journal of the Korean Operations Research and Management Science Society
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• v.28 no.3
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• pp.123-134
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• 2003

Fire Sequencing Problem (FSP) is to find a sequence of targets, where there exist a number of targets with different time units required to fire. Because of the weapon's specifications and the size of the targets, several weapons may fire on the same targets, and the time units required on firing for each weapon may be different from each other. The objective is to minimize the completion time of firing for given number of targets. Mathematical formulation is given, and the heuristic algorithm based on the paring of targets in advance is suggested. Performance of the heuristic is evaluated by comparison of heuristic appeared in the literature through the computational experiments.

• The KIPS Transactions:PartC
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• v.12C no.4 s.100
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• pp.489-494
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• 2005

In 2002, Shundong Xia proposed a new ID-based group signature scheme with strong separability. The nature of a strong separability is to divide group manager's role into a membership manager and a revocation manager Jianhong et al showed that the scheme was not coalition-resistant. In this letter, we first propose two new attacks, forgery and link attacks, for Xia-You's scheme. We also propose a new ID-based group signature scheme that Is resistant to coalition, forgery and link attacks

• Korean Institute of Interior Design Journal
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• no.38
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• pp.91-99
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• 2003

In the philosophical sense, aZen teacher would probably say there is no answer to the Question. Whatnis Zen\ulcorner Zen is an approach to life, a way of being , rather then a philisophy or set doctrine. Modern living people quest for peace and tranquility has led designers and decorators to look to East to the natural harmony and blance of Asian home and to the simpicity of their art and design. Zen style interiors are simplicity and serenity. These imply the paring down of a cluttered environment and concentration on creating harmony. balance, touch, and texture. By achieving these things you can create a place where the spiritual or inner needs can be addressed and where you can indulge in calming or stimulating the senses with light, space, and free flow of energy In Zen interior we approach 'Homoㆍaesthetcus' by feeling and' Homoㆍreligious' by mind. "Less is more", this phrase has made the pared down environment an interior form.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2006.11a
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• pp.209-212
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• 2006

To develop in the long view, based on context of city, the spatial program change to new spatial program that can be adopt city architectural environment. The new spatial program must have paring lot, open space, community center, which are infra structure for citizen. The needs about flexible space Increase according to complexity of spatial program. The space of absolutism, is made up hierarchy, can't accommodate complexity of spatial program. Therefore, modern architectural spaces are characterized by non-hierarchy. This research is tendency to search special quality of space program that is going complex composition according to change of modern society and modern architecture space, and analyze characteristic of inner space that have non-hierarchy to correspond hereupon.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.114-121
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• 1998

This paper presents the model updating of an equipment panel by using modal test and sensitivity analysis. The equipment panel is one of the major structures of communication satellite, on which broadcasting and communication equipments are mounted. For high rigidity and light weight, the panel was designed as an aluminum honeycomb sandwich panel. In addition, heat pipes were embedded in the panel for thermal control. It is essential to improve the finite element model of a satellite by using modal test in order to verify the satellite is designed with adequate margin under launch environment. In this paper, Young's modulus of aluminum facesheet was selected as a modified parameter by sensitivity analysis. The effect of rotational springs of boundary points was also considered.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.119.3-119
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• 2001

When building a network-based real-time control system, a network-induced delay time should be surly considered for real time schedulability to be guaranteed. The network delay time on end-to-end communication has been analyzed theoretically and modeled mathematically from many previous works. There also exist any other delay element not considered before. In this paper, the remote feedback control system using the CAN protocol is proposed to control three axes´ manipulator arm and the application layer of CAN is modeled to analyze the delay elements defined by three types of time delay: Software delay time, Controller delay time, and Access delay time, in details. The analyzed results are used as an important component to determine PID gains of the proposed system. The effect of the delay time on the control performance is evaluated by com paring the response characteristics of the control system through simulation.