• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.03a
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• pp.148-156
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• 2003

Shaking table tests and pseudo-static analysis were performed, in this study, on newly-designed aseismatic L-type caisson quay walls, which were constructed by extending the bottom plate of gravity quay walls into the backfill soil. The L-type quay walls are expected to give economical benefits by reducing the cross-sectional area of the wall while maintaining its aseismatic efficiency as much as the classical caisson gravity quay wall. To confirm the effectiveness of the L-type structure, the geometry of L-type quay walls were varied for shaking table tests. And, to verify the influence of backfill soils on the seismic behavior of quay walls, additional shaking table tests were performed on the L-type quay wall after the backfill soils were replaced by gravels and light materials. As a result, it was found that L-type caisson quay walls are good earthquake resistant structures but increasing the length of bottom plate did not proportionally increase the effectiveness of the structure in its aseismatic performance. Replacing the backfill soils by the gravels and light materials, contrary to our expectation, was not an effective measure in improving the seismic performance of L-type caisson quay wall.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.19-20
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• 2009

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.165-170
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• 1992

In this paper, the Hardware-In-The-Loop Simulation(HILS) of missile systems are studied. The HILS is an effective performance evaluation technique that bridges the simulation fidelity gap between analytic all-digital simulations and actual flight tests of missile systems. The HILS may be required to perform system integration tests, performance evaluation at system or subsystem level. Major elements of this HILS facility will include the flight table, simulation computers, I/O computer and peripheral equipments. HILS of missile systems typically involve computer modeling of flight dynamics coupled with a hardware guidance and control(G/C) systems. This paper describes a real time performance evaluation technique of a G/C system, Development of a HILS for a Autopilot of SAM G/C will be used as an example.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.11
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• pp.1299-1310
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• 1992

Recently, digital realizations of timing recovery circuits for digital data transmission are of growing interest. As a result of digital realization of timing recovery circuits, new digital algorithms for timing error detection are required. In this paper, we present a new digital Angular Form(AF) algorithm which can be directly applied to QPSK modulation technique. AF algorithm is basically developed on the concepts of detected angle form and transition logic table. We evaluated the performance of this algorithm by Monte-Carlo simulation method under Gaussian and Impulsive noise environments. From the performance evaluation result, we show that the performance of AF Algorithm is better than that of Gardner in BER, RMS jitter, S-curve.

• International journal of advanced smart convergence
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• v.10 no.1
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• pp.142-150
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• 2021

Open-channel SSD is a new type of Solid-State Disk (SSD) that improves the garbage collection overhead and write amplification due to physical constraints of NAND flash memory by exposing the internal structure of the SSD to the host. However, the host-level Flash Translation Layer (FTL) provided for open-channel SSDs in the current Linux kernel consumes host memory excessively because it use page-level mapping table to translate logical address to physical address. Therefore, in this paper, we implemente a selective mapping table loading scheme that loads only a currently required part of the mapping table to the mapping table cache from SSD instead of entire mapping table. In addition, to increase the hit ratio of the mapping table cache, filesystem information and mapping table access history are utilized for cache replacement policy. The proposed scheme is implemented in the host-level FTL of the Linux kernel and evaluated using open-channel SSD emulator. According to the evaluation results, we can achieve 80% of I/O performance using the only 32% of memory usage compared to the previous host-level FTL.

• Proceedings of the KSR Conference
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• 1998.05a
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• pp.427-435
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• 1998

In this paper will be presented an algorithm for designing of a railway interlocking table which is a document describing the functional specification of the interlocking device. The ability to produce an interlocking table has been handed down in the signalling engineers society. And the signalling engineer makes the most of his expertise to produce an interlocking table. But, the expertise has not yet been organized into technical system, the core of the expertise is a hard nut to crack. Therefore, we analyze into signal engineering expertise, and propose a generalization of interlocking notion. Also, an algorithm is drawn up based on a train route setting principle to solve practical and general problems by computer And the performance of the algorithm is evaluated for test program based on AutoCAD technology. The evaluation result shows that it can be utilized as the effective algorithm for computer control of the signalling system as interlocking device, that it improved in safety

• Journal of the Korea Safety Management & Science
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• v.20 no.1
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• pp.41-55
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• 2018

For several decades, attribute classification methods using the asymmetrical relationship between an attribute performance and the satisfaction of that attribute have been explored by numerous researchers. In particular, the Kano model, which classifies quality attributes into 5 elements using simple questionnaire and two-dimensional evaluation table, has gained popularity: Attractive, One-dimensional, Must-be, Indifferent, and Reverse quality. As Kano's model is well accepted, many literatures have introduced categorization methods using the Kano's evaluation table at attribute level. However, they applied different terminologies and classification criteria and this causes confusion and misunderstanding. Therefore, a criterion for quality classification at attribute level is necessary. This study is aimed to suggest a new attribute classification method that sub-categorizes quality attributes using 5-point ordinal point and Kano's two-dimensional evaluation table through an extensive literature review. For this, the current study examines the intrinsic and extrinsic problems of the well-recognized Kano model that have been used for measuring customer satisfaction of products and services. For empirical study, the author conducted a comparative study between the results of Kano's model and the proposed method for an e-learning case (33 attributes). Results show that the proposed method is better in terms of ease of use and understanding of kano's results and this result will contribute to the further development of the attractive quality theory that enables to understand both the customers explicit and implicit needs.

• Structural Engineering and Mechanics
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• v.59 no.2
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• pp.291-312
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• 2016

Seismic performance evaluation of shear wall is essential as it is the major lateral load resisting member of a structure. The ultimate load and ultimate drift of the shear wall are the two most important parameters which need to be assessed experimentally and verified analytically. This paper comprises the results of monotonic tests, quasi-static cyclic tests and shake-table tests carried out on a midrise shear wall. The shear wall considered for the study is 1:5 scaled model of the shear wall of the internal structure of a reactor building. The analytical simulation of these tests is carried out using micro and macro modeling of the shear wall. This paper mainly consists of modification in the hysteretic macro model, developed for RC structural walls by Lestuzzi and Badoux in 2003. This modification is made by considering the stiffness degradation effect observed from the tests carried out and this modified model is then used for nonlinear dynamic analysis of the shear wall. The outcome of the paper gives the variation of the capacity, the failure patterns and the performance levels of the shear walls in all three types of tests. The change in the stiffness and the damping of the wall due to increased damage and cracking when subjected to seismic excitation is also highlighted in the paper.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.389-394
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• 2011

Existing FPS(Friction Pendulum System) is isolation system which is possible to isolate structures by pendulum characteristic from ground vibration. Structural natural frequency could be decided by designing the radius of curvature of FPS. Thus, response vibration could be reduced by changing natural frequency of structures from FPS. But effective periods of recorded seismic wave were various and estimation of earthquake characteristic could be difficult. If effective periods of seismic wave correspond to natural frequency of structures with FPS, resonance can be occurred. Therefore, CFPBS(Cone-type Friction Pendulum Bearing System) was developed for controlling the response acceleration and displacement by the slope of friction surfaces. Structural natural frequency with CFPBS can be changed according to position of ball on the friction surface which was designed cone-type. Therefore, Divergence of response could be controlled by CFPBS which had constantly changing natural frequency with low modal participation factor in wide-range. In this study, Seismic performance of CFPBS was evaluated by numerical analysis and shaking table test.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.7
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• pp.599-608
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• 2011

FPS(friction pendulum system) is an isolation system which is possible to isolate structures from earthquake by pendulum characteristic. Natural frequencies of the structures could be determined by designing the radius of curvature of FPS. Thus, response vibration could be reduced by changing natural frequency of structures from FPS. But effective periods of recorded seismic wave were various and estimation of earthquake characteristic could be difficult. If effective periods of seismic wave correspond to natural frequency of structures with FPS, resonance can be occurred. Therefore, CFPBS(cone-type friction pendulum bearing system) was developed for controlling the acceleration and displacement of structure by the slope of friction surfaces. Structural natural frequency with CFPBS can be changed according to position of ball on the friction surface which was designed cone-type. Therefore, superstructures on CFPBS could be isolated from earthquake. In this study, seismic performance of CFPBS was evaluated by numerical analysis and shaking table test.