• Journal of Institute of Control, Robotics and Systems
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• v.17 no.11
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• pp.1082-1089
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• 2011

Most engineered systems are designed with high levels of system redundancies to satisfy required reliability requirements under adverse events, resulting in high systems' LCCs (Life-Cycle Costs). Recent years have seen a surge of interest and tremendous advance in PHM (Prognostics and Health Management) methods that detect, diagnose, and predict the effects of adverse events. The PHM methods enable proactive maintenance decisions, giving rise to adaptive reliability. In this paper, we present a RAP (Resilience Allocation Problem) whose goal is to allocate reliability and PHM efficiency to components in an engineering context. The optimally allocated reliability and PHM efficiency levels serve as the design specifications for the system RBDO (Reliability-Based Design Optimization) and the system PHM design, which can be used to derive the detailed design of components and PHM units. The RAP is demonstrated using a simplified aircraft control actuator design problem resulting in a highly resilient actuator with optimally allocated reliability, PHM efficiency and redundancy for the given parameter settings.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.648-655
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• 2005

The resilient mounts of a diesel engine installed onboard a ship should be designed for both static and dynamic loads. If possible, the resonance frequencies of the six rigid body modes of the installation and the flexible modes of the engine support structure should not lie within the engine operation range. In this paper a design criterion is proposed to evaluate an isolation system which involves the summation of dynamic forces transmitted through the resilient mounts and elastic potential energy index stored in the mounts. A case study is also presented in which a diesel engine generator, which had an elastic foundation and was mounted in a 5500 TEU container vessel, was studied both theoretically and experimentally. The theoretical analysis of the test model was performed by using a single mass 6 degree of freedom system. Actual measurements of mechanical vibration of the Engine and its foundation onboard were carried out, which showed the importance of including the flexibility of the engine support structure in the mode

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.1003-1006
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• 2002

In the communications systems with diversity, we are commonly faced on needing of new source coding technique, error resilient coding. The error resilient coding addresses the coding algorithm that has the robustness to unreliability of communications channel. In recent years, many error resilient coding techniques were proposed such as data partitioning, resynchronization, error detection, concealment, reference picture selection and multiple description coding (MDC). Especially, the MDC using correlating transform explicitly adds correlation between two descriptions to enable the estimation of one set from the other. However, in the conventional correlating transform method, there is a critical problem that decoder must know statistics of original image. In this paper, we propose an enhanced method, the MDC using whitening transform that is not necessary additional statistical information to decode image because the DCT coefficients to apply whitening transform to an image have uni-variance statistics. Our experimental results show that the proposed method achieves a good trade-off between the coding efficiency and the reconstruction quality. In the proposed method, the PSNR of images reconstructed from two descriptions is about 0.7dB higher than conventional method at the 1.0 BPP and from only one description is about 1,8dB higher at the same rate.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.4
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• pp.83-92
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• 1989

For many of the rigid pavements the observations of significantly different performances were explained to relate distress mechanisms to distress manifestation and to develope better prediction of performance. This paper summarizes the result of an investigation of the resilient elastic and fatigue behavior of inservice cement concrete pavements. Static indirect tensile tests were. conducted in order to estimate the average tensile strength of each of the projects Repeat-load indirect tensile tests were conducted to determine the fatigue and resilient elastic characteristics and the relationship between fatigue life and stress/strength ratio. Deformation measurements were taken during fatigue testing in order to determine the resilient elastic properties of the material and the changes in these properties during the test period.

• Journal of KSNVE
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• v.9 no.3
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• pp.477-484
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• 1999

This study aims to present proper thickness of resilient mount and pattern of chips for the improvement of impact sound isolation. To achieve this aim, field tests were performed to evaluate the performance of impact sound isolation of pilot samples using waste tire chips against light and heavy-weight impacter, which samples were installed over concrete slabs of an apartment housing. In this study, the experiments were performed by the impact sound level of floors in KS F 2810 "Method for field measurement of floor impact level". As results, a flooring structure using waste tire chips as a resilient mount, with no relation to chip's types, has enhanced performance by 1~2 degree in light impact sound isolation, while it has improvement in heavy impact sound isolation. And fiber-type chips have better performance than granule-type ones when they overlaid concrete slab with 15~20 mm of thickness. For the improvement of impact sound isolation, it is recommended that insulating materials should be applied at joints between floating floors and walls, or floating floors and a doorframes, and also waterproof papers should be used for the effective thickness of resilient mount.ent mount.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.3
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• pp.218-225
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• 2013

Vertically-launched missiles are supported as erected vertically in the vertical launching system of warship, and they should be mounted in the same way when vibration-tested. However, mounting missiles vertically makes a fixture, which is a supporting structure, bulky and heavy so requiring a high-performance exciter. Mounting missiles as laid down horizontally in a vibration test is economical regarding fixture manufacturing and exciter performance, but it makes test results incorrect because the different mounting direction has effects on the test results. A bending moment due to missiles' weight happens to missiles, and resilient mounts, which support missiles in the vertical launch system, deflect differently from the real situation because of the static deflection of these mounts due to missiles' weight. If the resilient mounts supporting missiles have nonlinear force-deflection characteristics, vibration test results become more different from the true results. This paper proposes to support missiles with an additional resilient mount such as a bunge code in order to solve those problems coming from mounting vertically-launched missiles as laid down horizontally in vibration tests. The proposed approach enables to obtain the same test results as in their actual mounting condition even though vertically-launched missiles are mounted in a different direction.

• Journal of the Korean GEO-environmental Society
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• v.13 no.9
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• pp.61-68
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• 2012

The main objective of this study is to develop an analytical model for the resilient modulus of EPS geofoam when it is applied for flexible pavement as a subgrade material. This analytical model has been developed based on the results from triaxial compression tests. And this model can be used to analyze the flexible pavement structure using the finite element method by developing a program or modifying an existing program for any desired purposes. The results of this study show that the EPS geofoam as a replacement material for subgrade in flexible pavement is a feasible alternative to natural weak soils.

• International Journal of Highway Engineering
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• v.11 no.3
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• pp.75-83
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• 2009

A need still exists to evaluate the durability performance of cemented gedmaterials in road constructions using various cementing binders due to seasonal changes in fields as well as structural performance. In this paper, durability characteristics of stabilized granular base and subgrade materials, which is widely used in korea, was assessed using a laboratory repeated load resilient-deformation test under various freezing-thawing and wet-drying cyclic conditions. In addition, various resilient modulus models were adopted based on the test results. As a result, the estimated model coefficients agree well with the values from the literatures.

• International Journal of Highway Engineering
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• v.15 no.2
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• pp.83-94
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• 2013

PURPOSES : In Korea, most designs of pavement had been mainly performed by considering CBR of granular materials before KPRP(Korea Pavement Research Program) and 86 AASHTO design method were introduced. Since then, the trend of the pavement designs gradually have moved to using mechanical characteristics throughout the resilient modulus based on the test results up to recently. In this study, we should like to research the mechanical characteristics of paving materials containing Recycled aggregates through the cyclic loading triaxial compression tests. METHODS : The kinds of materials were tested; coarse grained subbase materials, refining aggregates base materials and recycled aggregates. RESULTS : The present study aims to figure out the resilient modulus of paving materials containing Recycled aggregates through the cyclic loading triaxial compression tests. CONCLUSIONS : The test results revealed that the engineering properties of the recycled aggregates were more excellent than the those of others.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.4 s.109
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• pp.329-338
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• 2006

The resilient mounts of a diesel engine installed onboard a ship should be designed for both static and dynamic loads. If possible, the resonance frequencies of the six rigid body modes of the installation and the flexible modes of the engine support structure should not lie within the engine operation range. In this paper a design criterion is proposed to evaluate an isolation system which involves the summation of dynamic forces transmitted through the resilient mounts and elastic potential energy index stored in the mounts. A case study is also presented in which a diesel engine generator, which had an elastic foundation and was mounted in a 5500 TEU container vessel, was studied both theoretically and experimentally. The theoretical analysis of the test model was performed by using a single mass 6 degree of freedom system. Actual measurements of mechanical vibration of the engine and its foundation onboard were carried out, which showed the importance of including the flexibility of the engine support structure in the mode.