• Journal of KSNVE
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• v.3 no.4
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• pp.373-382
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• 1993

Active micro-vibration control of a structure, which simulates a stepper device, is performed using a pair of piezolectric actuators. The control aims at reducing the translational and rotational vibrations of the upper plate when the base is subject to seismic disturbance and the upper plate undergoes impulsive transient motion. Using the experimentally determined model, derivative control scheme is adopted so that the damping of the closed-loop system is effectively increased. It is found that the predicted control performance is in good agreement with the experimental results. Finally, the limit cycle phenomenon due to the controller voltage saturation is compared with the simulation.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.343-350
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• 2002

The structural stability of pressure housing of SMART CEDM forming pressure boundary must be evaluated. In this paper, the stress and thermal analyses of the upper pressure housing of CEDM are performed for design pressure, hydraulic test pressure and thermal loading. Finite element and boundary condition were generated from the model which is made by I-DEAS program and the stress and thermal analyses were performed by ANSYS Program. The upper Pressure housing was analysed using 2D axisymmetric model because it is symmetry about an axis. The stress values obtained by analysis were compared with the stress intensity limit of ASME and KEPIC MNB standard.

• Advances in Computational Design
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• v.1 no.3
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• pp.221-234
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• 2016

The present study dictates the behavior of shear wall under a seismic event in slender high rise buildings, and studies the effect of height, location and distribution of shear wall in slender high rise building with and without boundary elements induced by the effect of an earthquake. Shear walls are located at the sides of the building, to counter the earthquake forces. This study is carried out in a 12 storeys building using SAP2000 software. The obtained results disclose that the behavior of the structure is definitely affected by the height and location of shear walls in slender high rise building. The stresses are concentrated at the limit between the shear wall region and the upper non shear wall especially for shear walls without columns. Displacements are doubled between the shear wall region and the upper non shear wall especially for shear walls without columns.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11C
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• pp.907-910
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• 2010

This paper presents the design of block lengths for irregular low-density parity-check (LDPC) codes based on the maximum variable degree $d_{{\upsilon},max}$. To design a block length, the performance degradation of belief-propagation (BP) decoding performance from upper bounds on the maximum likelihood (ML) decoding performance is used as an important factor. Since for large block lengths, the performance of irregular LDPC codes is very close to the Shannon limit, we focus on moderate block lengths ($5{\times}10^2\;{\leq}\;N\;{\leq}\;4{\times}10^3$). Given degree distributions, the purpose of our paper is to find proper block lengths based on the maximum variable degree $d_{{\upsilon},max}$. We also present some simulation results which show how a block length can be optimized.

• Journal of the Korean Society of Safety
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• v.29 no.4
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• pp.85-90
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• 2014

For the safe handling of acetic anhydride, this study was investigated the explosion limits of acetic anhydride in the reference data. And the lower flash points, upper flash points, and AITs(auto-ignition temperatures) by ignition delay time were experimented. The lower and upper explosion limits of acetic anhydride by the investigation of the literatures recommended 2.9 Vol% and 10.3 Vol.%, respectively. The lower flash point of acetic anhydride by using Setaflash closed-cup tester was experimented $49^{\circ}C$. The lower flash point acetic anhydride by using Tag and Cleveland open cup tester were experimented $55^{\circ}C$and $62^{\circ}C$, respectively. Also, this study measured relationship between the AITs and the ignition delay times by using ASTM E659 tester for acetic anhydride. The experimental AIT of acetic anhydride was $350^{\circ}C$.

• Communications of the Korean Mathematical Society
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• v.36 no.4
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• pp.715-727
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• 2021

In this paper, we give some results an upper bound of Hankel determinant of H₂(1) for the classes of 𝓝 (𝜶). We get a sharp upper bound for H₂(1) = c₃ - c²₂ for 𝓝 (𝜶) by adding z₁, z₂, …, z_n zeros of f(z) which are different than zero. Moreover, in a class of analytic functions on the unit disc, assuming the existence of angular limit on the boundary point, the estimations below of the modulus of angular derivative have been obtained. Finally, the sharpness of the inequalities obtained in the presented theorems are proved.

• Geomechanics and Engineering
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• v.10 no.1
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• pp.21-35
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• 2016

Employing non-associated flow rule and Power-Law failure criterion, the failure mechanisms of tunnel roof in homogeneous and layered soils are studied in present analysis. From the viewpoint of energy, limit analysis upper bound theorem and variation principle are introduced to study the influence of dilatancy on the collapse mechanism of rectangular tunnel considering effects of supporting force and seepage force. Through calculation, the collapsing curve expressions of rectangular tunnel which are excavated in homogeneous soil and layered soils respectively are derived. The accuracy of this work is verified by comparing with the existing research results. The collapsing surface shapes with different dilatancy coefficients are draw out and the influence of dilatancy coefficient on possible collapsing range is analyzed. The results show that, in homogeneous soil, the potential collapsing range decreases with the decrease of the dilatancy coefficient. In layered soils, the total height and the width on the layered position of possible collapsing block increase and the width of the falling block on tunnel roof decrease when only the upper soil's dilatancy coefficient decrease. When only the lower soil's dilatancy coefficient decrease or both layers' dilatancy coefficients decrease, the range of the potential collapsing block reduces.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.10
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• pp.847-852
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• 2016

In this paper, important design parameters for parallel kinematic robots are defined, paying special attention to machining errors which may cause kinematic errors at the end effector of a robot. The kinematic effects caused by each design parameter, as well as their upper/lower limits, are analyzed here. To do so, we have developed a novel software program to compute kinematic errors by considering its defined design parameters. With this program, roboticists designing parallel kinematic robots can understand the important design parameters for which upper/lower allowances have to be strictly controlled in the design process. This tactic can be used for the design of high-speed, parallel kinematic robots to reduce the design/manufacturing costs and increase kinematic precision.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.1
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• pp.8-14
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• 2013

A low density parity check (LDPC) decoder provides a most powerful error control capability for mobile communication devices and storage systems, due to its performance being close to Shannon's limit. In this paper, we introduce an efficient overlapped LDPC decoding algorithm using a upper dual-diagonal parity check matrix structure. By means of this algorithm, the LDPC decoder can concurrently execute parts of the check node update and variable node update in the sum-product algorithm. In this way, we can reduce the number of clock cycles per iteration as well as reduce the total latency. The proposed decoding structure offers a very simple control and is very flexible in terms of the variable bit length and variable code rate. The experiment results show that the proposed decoder can complete the decoding of codewords within 70% of the number of clock cycles required for a conventional non-overlapped decoder. The proposed design also reduces the power consumption by 33% when compared to the non-overlapped design.

• PNF and Movement
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• v.3 no.1
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• pp.27-34
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• 2005

Objective : The purpose of this study was conducted to find correct head and neck patterns, manual contact. verbal commands with proprioceptive neuromuscular facilitation(PNF). Method : This is a literature study with books, seminar note and book for PNF international course. Result : Keep the information of the biomechanics and neural science in head and neck patterns and emphasize that manual contact, verbal commands and visual stimulus. Manual contacting for movement guide and stability of the $C_0/C_1$ verbal command and visual stimulus for correcting of the $C_0/C_1$ movements. Conclusion : In reminder for PNF learning, begin with head and neck and upper trunk patterns. In that time, Knott and Voss(1968) had not enough information about biomechanic movement components and neural science movement components. But Knott and Voss(1968) emphasized that head and neck patterns relate with trunk, upper extremities and lower extremities directly. Alar ligaments are relaxed with the head in neutral and taut in flexion. Axial rotation of the head and neck tightens both alar ligaments. The right upper and left lower portions of the alar ligament limit left lateral flexion of the head and neck. Therefore, head and neck patterns has to be modify. When head moving, eye and vestibular stimulus will be change. During head and neck patterns, must be consider about stimulus of eye system and vestibular system also.