• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.7B
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• pp.550-556
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• 2008

Swam intelligence refers that a large group of simple and unsophisticated entities work together to achieve complex and significant tasks. Researches using such swarm intelligence has been performed in the network routing area. Expecially, it has been well known that routing in mobile ad-hoc networks whose features are dynamic topology and routing based on the local information is one of the applications of swarm intelligence. In this paper, we propose an ant-based routing method for MANET. The proposed method sets its goals to reduce overheads by managing ants efficiently, and to reduce route set up time. The results obtained from simulations proved that the proposed method provides shorter path set-up time and end-to-end delay and less overhead while providing comparable packet delivery ratio.

• Korean System Dynamics Review
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• v.4 no.1
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• pp.69-91
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• 2003

Using qualitative methods hinged on urban dynamics models, the paper addresses major issues concerned with new administrative capital construction. It tries to summarize the existing debates on new administrative capital construction and reinterpret diverse interacting factors in terms of reinforcing or balancing feedback structure. The paper suggests that understanding up on the dynamic mechanism imbedded in circular causal loop diagrams is the key to set up appropriate proposals and action plans for the new administrative capital, as they would reveal complicated linkages between the Capital Region and the rest, in addition to the urban dynamic of new administrative capital. In the same context, the paper can confirm similar features reflected in the relocation of capital functions at Canberra, Australia and Berlin, Germany. It has paid special attention to the fact that both Australian and German governments altogether stress the positive feedback loops as they have overcome unprecedented political confrontation among rival cities: Basically, they have encouraged gives-and-takes among major stake-holders. These research findings indicate that the future of new administrative capital construction depends on consensus buildings that can accommodate socio-economic and territorial changes between pros and cons. Although further researches and validations are needed, the system approach presented in this paper could assist Korean decision-makers in developing robust and responsive policy initiatives under uncertainties.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.238-243
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• 2004

A new sandwich composite was investigated in this paper. The honeycomb core of this composite was filled with viscoelastic material in order to obtain an improved damping performance. The viscoelastic fillings in the honeycomb cells was hoped to act as dampers and provide the function of energy dissipation in this combined material system. Dynamic test was set up to the specimens with various stacked carbon/epoxy laminate facesheets, $[0/90]_{4s}$, $[0/45/-45/90]_{2s}$, $[45/-45]_{4s}$. Frequency response, displacement response and damping ratio were checked and compared for the both groups of specimens, with and without rubber fillings. The experimental results provided a good agreement with our material design concept.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1143-1148
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• 2007

LRE(Liquid propellant Rocket Engine) is one of the important parts to control the motion of rocket. For operation of rocket in error boundary of the set-up trajectory, it is necessarily to control the thrust of LRE according to the required thrust profile and control the mixture ratio of propellants fed into combustor for the constant mixture ratio. It is not easy to control thrust and mixture ratio of propellants since there are co-interferences among the components of LRE. In this study, the dynamic model of LRE was constructed and the dynamic characteristics were analyzed with control system as PID control and PID+Q-ILC(Iterative Learning Control with Quadratic Criterion) control. From the analysis, it could be observed that PID+Q-ILC control logic is more useful than standard PID control system for control of LRE.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.7
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• pp.132-143
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• 1999

In this study, an intermediate model is presented as a new method for development of a parametric simulation program. This model enables us to analyze effectively the static and dynamic structure of a real production system. The static structure of the real system can be modelled in an entity-relationship diagram and the dynamic structure of the real system in a Petri net. The intermediate model consists of an entity-relationship diagram and a Petri net. Using this intermediate model man can not only reduce the time and cost for simulation program development, but also increase the modelling reliability of the developed simulation program. To show the usefulness of this intermediate model. the intermediate models for two production subsystems, manufacturing sub-system and transport subsystem, are set up.

• Transactions of the Korean Society of Automotive Engineers
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• v.1 no.1
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• pp.120-130
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• 1993

In the analysis of automobile exhaust system, the exciting forces from the engine determine the dynamic behavior of the system and the dynamic characteristics influence the riding quality. Therefore, the identification of the force in numeric value is quite important for the vibrational reduction. However, the value is difficult to obtain by experiments due to harsh conditions around the engine. In this research, an optimization technology is adopted to evaluate the exciting forces. An experimental method is conducted for the verification of the finite element modeling. Displacements on the end of the exhaust system are measured under the idling environment. cost function is set up to minimize the differences between the displacements of the numerical simulation and the experiment. Design variables are the components of the exciting forces. That is, optimization is utilized to estimate the forces with existing data. Excellent estimations have been calculated efficiently and the information is used again for the forced vibration of the exhaust system.

• Smart Structures and Systems
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• v.6 no.1
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• pp.57-72
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• 2010

This paper presents the most significant results obtained within a broad-ranging experimental program aiming to evaluate both the effectiveness and the robustness of a Base Isolation (BIS) and a Tuned Mass Damper (TMD) combined control strategy (BI & TMD). Following a brief description of the experimental model set-up and the adopted kinematic scaling technique, this paper describes the identification procedures carried out to characterize the system''s model. The dynamic response of a small-scale model to recorded earthquake excitations, which has been scaled by using the Buckingham pi-theorem, are later presented and discussed. Finally, the effectiveness and robustness of the combined control strategy is evaluated by comparing the model's dynamic response. In particular, reduction in relative displacements and absolute accelerations due to the application of different mass damping systems is investigated.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.1
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• pp.33-43
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• 1998

Dynamic behavior of a scroll compressor has been investigated analytically. The equations of motion of moving elements of the scroll compressor such as the orbiting scroll, anti-rotation device, slider bush, and the crank shaft with eccentric crank pin have been set up. As the solutions of these equations, reaction forces between the moving elements, and also between the moving elements and the compressor frame have been calculated. The reaction forces from the moving elements to the frame are the unbalanced forces, which produce accelerations of the compressor body. These accelerations can be used as a measure of the compressor vibration. The major contributions to the unbalanced forces come from the orbiting movement of the orbiting scroll.

• Structural Engineering and Mechanics
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• v.2 no.2
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• pp.157-171
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• 1994

A general approach to the dynamic time-history analysis of the reactor core is presented in this paper as a part of the fuel assembly qualification program. Several detailed core models are set up to reflect the placement of the fuel assemblies within the core shroud. Peak horizontal responses are obtained for each model for the motions induced form earthquake. The dynamic responses such as fuel assembly deflected shapes and spacer grid impact loads are carefully investigated. Also, the sensitivity responses are obtained for the earthquake motions and the fuel assembly non-linear response characteristics are discussed.

• 한국공간정보시스템학회:학술대회논문집
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• 2004.05a
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• pp.176-183
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• 2004

Deployable structures are space frames consisting of straight bars that are linked together into bundle and can be deployed large, load bearing structures. Deployable structures are easy to set up, to assemble, to disassemble, to transport and to keep for the use. Also, reusability and flexibility are another important advantages for environmental matter. Since deployable structures have various advantages, they offer viable alternatives for a wide range of potential applications in the temporary construction industry as well as in the aerospace industry. The purpose of this thesis is to decide on geometrical parameters of the design through the numerical analysis and create a final configuration of deployable structures using the geometrical parameters. The Multibody Dynamic Analysis that is dealt with mechanics and aeronautics is used for the method of analysis.