• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.63.4-64
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• 2016

We aim to investigate inflow history of matters that fall into the satellite systems around a dwarf galaxy in Lambda-Cold Dark Matter model. Each satellite system has unique properties because all satellite systems have different mass inflow history by environments and/or the events such as cosmic reionization and merging with other halos. To trace mass inflow history of the satellite systems, we perform three different cosmological zoom simulations whose galaxy mass is ${\sim}10^{10}M_{sun}$. Each initial zoom simulation covers a cubic box of $1Mpc/h^3$ with 17 million particles. Particle mass for dark matter (DM) and gas components is $M_{DM}=4.1{\times}10^3M_{sun}$ and $M_{gas}=7.9{\times}10^2M_{sun}$, respectively. Thus, each satellite system is resolved with more than hundreds - thousands of particles. We analyze the influence of the gravitational interaction with host galaxy, baryonic matter inflow by various cooling mechanisms, and merging events with other halos on the mass inflow history of satellite systems.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.43 no.5 s.311
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• pp.80-88
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• 2006

In this paper we developed a novel system for automatic detection of mass type breast cancer on dense digital mammogram images. The new approaches presented in this paper are as follows: 1) we presented a method that stably decides the mass center and radius without being affected by image signal irregularity. 2) We developed a radial directional filter that is suitable to process mass image signal. 3) And we developed the multiple feature function based on mass shape spiculation, mass center homogeneity, and mass eccentricity, so as to determine mass-type breast cancer. When the proposed system is applied to dense mammographic images, the true 기arm rate is improved by 10% over a conventional system while the false alarm is increased by 1 per image.

• Smart Structures and Systems
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• v.15 no.3
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• pp.863-879
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• 2015

This paper experimentally investigates the effectiveness and applicability of the time delay control (TDC) algorithm, which is simple and robust to unknown system dynamics and disturbance, for an active mass damper (AMD) system to mitigate the excessive vibration of a building structure. To this end, the theoretical background including the mathematical formulation of the control system is first described; and then, a thorough experimental study using a shaking table system with a small-scale three-story building structural model is conducted. In the experimental tests, the performance of the proposed control system is examined by comparing its structural responses with those of the uncontrolled system in the free vibration and forced vibration cases. It is clearly verified from the test results that the TDC algorithm embedded AMD system can effectively reduce the structural response of the building structure.

• Coupled systems mechanics
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• v.3 no.3
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• pp.267-289
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• 2014

A proper physical modeling of infilled building frame-foundation beam-soil mass interaction system is needed to predict more realistic and accurate structural behavior under static vertical loading. This is achieved via finite element method considering the superstructure, foundation and soil mass as a single integral compatible structural unit. The physical modelling is achieved via use of finite element method, which requires the use of variety of isoparametric elements with different degrees of freedom. The unbounded domain of the soil mass has been discretized with coupled finite-infinite elements to achieve computational economy. The nonlinearity of soil mass plays an important role in the redistribution of forces in the superstructure. The nonlinear behaviour of the soil mass is modeled using hyperbolic model. The incremental-iterative nonlinear solution algorithm has been adopted for carrying out the nonlinear elastic interaction analysis of a two-bay two-storey infilled building frame. The frame and the infill have been considered to behave in linear elastic manner, whereas the subsoil in nonlinear elastic manner. In this paper, the computational methodology adopted for nonlinear soil-structure interaction analysis of infilled frame-foundation-soil system has been presented.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.97-99
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• 2002

최근 PC 시장은 USB라는 새로운 인터페이스의 보급으로 이용한 장치들이 급속도로 증가하고 있다. 또한 USB를 이용하여 저장 장치를 접근할 수 USB Mass Storage는 디지털 카메라나 MP3 Player 등에서 빠른 전송속도와 편리함 때문에 각광 받고 있다. 본 논문에서는 실시간 운영 체제인 iRTOS$^{TM}$에서 USB 인터페이스를 이용한 USB Mass Storage가 가능하도록 설계하고 이를 구현한 내용을 기술한다.

• Journal of the Korean Society of Safety
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• v.12 no.3
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• pp.17-22
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• 1997

This paper reals with the structure and function of duel mass flywheel. Damping effects of engine rotational fluctuation are compared with those of pre-damper clutch and duel mass flywheel and driven- system behavior is estimated engine idle r.p.m. The reason of gear rattle noise is higher in summer than winter and driving longer period than initial driving is due to affection by drag torque changing. The above-contents can be used on the design of clutch system and transmission matching including engine and duel mass flywheel.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2001.06a
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• pp.129-132
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• 2001

she purpose of this paper is to propose an approach to suppress the vibration of three-mass inertia system based on the LMI theory. and confirm its validity through simulations under the condition of parameter variation. First, the existing $H_{\infty}$ servo problem is modified to a structure to which the LMI theory can be applied by virtue of the interval model principle. By adopting this structure, we can divide given specifications fur the vibration suppression problem into $H_2$and $H_{\infty}$ performance criteria. The results of simulation for the three-mass inertia system show that the proposed design approach is quite effective.

• Smart Structures and Systems
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• v.5 no.3
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• pp.279-290
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• 2009

Two degrees of freedom resonant systems are employed to improve the resonant property of resonant sensor, as compared to a single degree of freedom resonant system. This paper presents design, development and testing of two degrees of freedom resonant sensor. To measure absolute mass, cantilever shaped two different masses (smaller/absorber mass and bigger/drive mass) with identical resonant frequency are mechanically linked to form 2 - Degree-of-Freedom (DOF) resonator which exhibits higher amplitude of displacement at the smaller mass. The same concept is extended for measuring differential quantity, by having two bigger mass and one smaller mass. The main features of this work are the 3 - DOF resonator for differential detection and the microcontroller based closed loop electronics for resonant sensor with piezoelectric sensing and excitation. The advantage of using microcontroller is that the method can be easily extended for any range of measurand.

• Smart Media Journal
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• v.4 no.3
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• pp.62-67
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• 2015

The trend keywords in ICT sector will be Big Data, Internet of Things, and Cloud Computing. The rear end to support those techniques requires a large-capacity storage technology of low-cost. Therefore, we proposed the prototype of low-cost and mass distributed storage system based on PC using open-source Ceph FS for SMB.

• Architectural research
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• v.14 no.3
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• pp.99-108
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• 2012

An innovative multi-story Semi-Active Tuned Mass Damper (SATMD) building system is proposed to control seismic response of existing structures. The application of adding new stories as large tuned mass and semi-active (SA) resettable actuators as central features of the control scheme is derived. For the effective control of the structures, the optimal tuning parameters are considered for the large mass ratio, for which a previously proposed equation is used and the practical optimal stiffness is allocated to the actuator stiffness and rubber bearing stiffness. A two-degree-of freedom (2-DOF) model is adopted to verify the principal efficiency of the suggested structural control concept. The simulations for this study utilizes the three ground motions, from SAC project, having probability of exceedance of 50% in 50 years, 10% in 50 years, and 2% in 50 years for the Los Angeles region. 12-story moment resisting frames, which are modified as '12+2' and '12+4' story structures, are investigated to assess the viability and effectiveness of the system that aims to reduce the response of the buildings to earthquakes. The control ability of the SATMD scheme is compared to that of an uncontrolled and an ideal Passive Tuned Mass Damper (PTMD) building system. From the performance results of suggested '12+2' and '12+4' story retrofitting case studies, SATMD systems shows significant promise for application of structural control where extra stories might be added.