• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.461-466
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• 1993

This paper focuses on development and implementation of a performance management algorithm for IEEE802.4 token bus networks to serve large-sale integrated systems. The delivery of time critical messages within delay constraints is an important criterion in the design and management of computer communication networks. In order to achieve this goal, the theory of fuzzy sets has been employed to imitate human's reasoning. The Fuzzy Network Performance Manager(FNPM) is composed of two parts: FNPM1 & FNPM2. FNPM1 is solily intended to satisfy the data latencyfor the highest priority while the other part is trying to satisfy those for the lower priorities. The FNPM requires average data latency, throughput, and token circulation time for its inputs. The efficacy of the FNPM has been evaluated by a series of simulation experiments.

• Journal of architectural history
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• v.18 no.4
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• pp.25-41
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• 2009

Louis I. Kahn is cleary one of 20th century great architects. The character of his philosophy of architecture can be condensed as simple words; Architectural Essence, because the very nature of his work based on historicity is so fundamental. Some contemporary architects and architectural critics regard it as a symbol of Post-Modern Architecture era expressing relative multiplicity or an expression of Heideggerian existentialism, but others do as the attribute of fundamentalist like absolute Plato's Idea. Comparing the former, studies of the latter theme have been executed superficially and somewhat biasedly for last decades. In the context, this paper attempt to reanalyze Kahn's idea of 'Architectural Essence' with the deep view of Platonist focused on the concept of binary opposition and causality.

• Korean Journal of Acupuncture
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• v.28 no.3
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• pp.187-199
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• 2011

Objectives : Pyoyubu (標幽賦), one of the classics in the science of acupuncture and moxibustion was written by Tu hankyoung (竇漢卿) during the Kum-Won dynasty of China (A.D 1196-1280). This paper is to explore his academic thoughts and make its correct interpretation with new copious notes. Methods : The translation was based on Original Chimgudaesung (原本鍼灸大成) and revisals of Chimguchuiyoung (鍼灸聚英), Yukyoungbuik (類經附翼), New Chimgudaesung (新鍼灸大成), etc. The format of this paper is in poetry and prose in order to abide by the original text. Results and Conclusions : The final part is devoted to five critical thinking on the text, which provides the fundamental principles and clinical guidelines for the current theory of acupuncture.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.10a
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• pp.31-35
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• 2001

Three dimensional dynamic cutting can be postulated as an equivalent orthogonal dynamic cutting through the plane containing both the cutting vector and the chip flow velocity vector in cutting process. An analytical expression of dynamic cutting force is obtained from the cutting parameters determined by the static three dimensional cutting experiments. Particular attention is paid to the energy supplied to the vibration of the tool behind the vertical vibration and the direction. The phase lag of the horizontal vibration of the tool behind the vertical vibration and the direction angel of the fluctuating cutting force must be regarded in point of stability limits. Chatter vibration can effectively be suppressed by enlarging the dynamic rigidity of the cutting system in the vertical cutting force direction. A good agreement is found between the stability limits predicted by theory and the critical width of cut determined by experiments.

• Journal of the Korean Mathematical Society
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• v.55 no.1
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• pp.43-58
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• 2018

In this paper, we study a delayed predator-prey system with Holling type IV functional response incorporating the effect of habitat complexity. The results show that there exist stability switches and Hopf bifurcation occurs while the delay crosses a set of critical values. The explicit formulas which determine the direction and stability of Hopf bifurcation are obtained by the normal form theory and the center manifold theorem.

• Korean Journal of Mathematics
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• v.15 no.2
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• pp.149-165
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• 2007

We investigate the existence of multiple nontrivial solutions $u(x,t)$ for a perturbation $b[({\xi}-{\eta}+2)^+-2]$ of the hyperbolic system with Dirichlet boundary condition $$(0.1)\;L{\xi}={\mu}[({\xi}-{\eta}+2)^+-2]\;in\;({-{\frac{{\pi}}{2}}},{\frac{{\pi}}{2}}){\times}\mathbb{R},\\L{\eta}={\nu}[({\xi}-{\eta}+2)^+-2]\;in\;({-{\frac{{\pi}}{2}}},{\frac{{\pi}}{2}}){\times}\mathbb{R},$$, where $u^+$=max{u,o}, ${\mu}$, ${\nu}$ are nonzero constants. Here L is the wave operator in $\mathbb{R}^2$ and the nonlinearity $({\mu}-{\nu})[({\xi}-{\eta}+2)^+-2]$ crosses the eigenvalues of the wave operator.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.11a
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• pp.144-147
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• 2003

It is important to understand the process of technology diffusion among end users for effectively implementing adoption and coping with frequent changes in the environment. Previous studies indicate that information and communication technology (ICT) adoption is affected by innovation influence such as usefulness, ease of use and self-efficacy. Most of these studies, however, bypassed imitation influence such as subjective norms, word-of-mouth, and advertising, specifically, interactive innovation having critical mass in technology acceptance research. Thus, this study investigates imitation influence in individual adoption of mobile communication technology, more specifically, mobile phones, using Mahaian's diffusion model in individual ICT adoption.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.3
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• pp.49-55
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• 2010

In this paper, the stability of cracked cantilever T-beams subjected to subtangential follower force is investigated. Also, the effect of subtangential coefficient and crack on the natural frequency of T-beams is presented. Based on the Euler-Bernoulli beam theory, the equation of motion is derived by the energy expressions using extended Hamilton's Principle. The crack is assumed to be in the first mode of fracture and to be always opened during the vibrations. The values of critical follower force and the stability maps of cantilever T-beams are obtained according to the subtangential coefficient and crack severity. The results of this study will contribute to the safety testing and the stability estimation of cracked T-beams subjected to follower force.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.470-473
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• 1995

There exist two critical in application of the magnetic bearing system. One is the control axis interference caused by gyroscopic effect and the other is the vibration caused by the unbalance on the rotor. To solve both problems at the same time, first, a centralized full-state feedback controller based on the LQR control theory was designed to compensate for the gyroscopic effect. Second, disturbance rejection control input based on the observer was designed to avoid the vibration causer by the unbalanced rotor. Balancing input computer accroding to LQR and output of the observer were derived in term of rotational speed. Effectiveness of the on-line balancing was verified through numerical simulation. The developed observer-based controller was also applied to the linear and nonlinear magnetic bearing systems.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.846-851
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• 1995

A motor-integrated high-speed spindle system with .psi. 65*25, 000rpm is modeled for analytical and experimental studies related to the dynamic characteristics. And the systematic and rational identification processes for evaluating the material properties of spindle and built-in motor is introduced. The impulse excitation method is applied for the experimental model testing, and the dynamic characteristics of test model is theoretically analysed by using the finite element method based on Timoshenko theory. Especially, the experimental and theoetical results reveal that the test model under the required operational conditions has no critical problem for dynamic characteristics.