• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.8
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• pp.720-728
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• 2012

It is important for identification of noise and vibration problem of tire to consider influence of interaction between road and tire. A quantification of road noise is a challenging issue in vehicle NVH due to extremely complicated transfer paths of road noise as well as the difficulty in an experimental identification of input force from tire-road interaction. A noise caused by tire is divided into road noise(structure-borne noise) and pattern noise(air-borne noise). Pattern noise is caused by pattern shape of tire, which has larger than 500 Hz, but road noise is generated by the interactions between a tire and a vehicle body. In this paper, we define the quantitative analysis for road noise caused by interactions between tire and road parameters. For the identification of road noise, the chassis dynamometer that is equipped $10mm{\times}10mm $ square cleat in the semi-anechoic chamber is used, and the tire spindle forces are measured by load cell. The vibro-acoustic transfer function between ear position and wheel center was measured by the vibro-acoustic reciprocity method. In this study three tires with different type of mechanical are used for the experiment work.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.764-769
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• 2001

Brake-induced vibrations of a vehicle such as brake judder are determined by the excitation of brake torque variations and by their transfer to the driver's contact points via suspension, body and steering system. The formation of brake torque variation is mainly determined by static and dynamic disk thickness variations. The vibration transfer from the excitation by brake torque variation to the perception by the driver depends on the kinematic and dynamic behaviour of the components in the transfer path. Optimization of the judder performance can be achieved either by minimizing the excitation or by reduction of the judder sensitivity of the vehicle. In this paper, the optimization process of a front rotor is suggested to reduce brake judder considering the cooling performance of the rotor, the judder sensitivity of the vehicle and durability of the rotor.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.563-564
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• 2017

The core of the cloud computing technology is the data center in that the networking technology is important. Cloud data centers are comprised of tens or even hundreds of thousands of physical servers, so networking technology is required for high-speed data transfer. These networking technologies also require scalability, fault tolerance, and agility. For these requirements, many multi-path based schemes have been proposed. However, it was mainly used for load balancing of traffic and select a path randomly. In this paper, a scheme that can construct a multipath using software defined networking technology and transmit the traffic in parallel by using the multipath to achieve a fast transmission speed, solve the scalability problem and fault tolerance is proposed.

• Journal of Korean Society of Steel Construction
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• v.16 no.5 s.72
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• pp.599-607
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• 2004

As buildings become more high-rise and lightweight in recent years, steel has been utilized more frequently. Based on the American AISC standard, all axial loads could be carried through a bearing load in a column splice, but according to Korean codes, the bearing load has constrained the stress that could be carried by only 25% of all axial loads. Thus, new column splice methods that use metal touch have been examined. In this study, the stress path mechanism, as an intermediation parameter in the gap's magnitude, must be determined. Similarly, the behavioral aspect of the metal touch connection must be sought after comparing and analyzing the results of the test.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.11
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• pp.5271-5289
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• 2016

On large-scale data analysis platforms deployed on cloud infrastructures over the Internet, the instability of the data transfer time and the dynamics of the processing rate require a more sophisticated data distribution scheme which maximizes parallel efficiency by achieving the balanced load among participated computing elements and by eliminating the idle time of each computing element. In particular, under the constraints that have the real-time and limited data buffer (in-memory storage) are given, it needs more controllable mechanism to prevent both the overflow and the underflow of the finite buffer. In this paper, we propose an auto regulated data provisioning model based on receiver-driven data pull model. On this model, we provide a synchronized data replenishment mechanism that implicitly avoids the data buffer overflow as well as explicitly regulates the data buffer underflow by adequately adjusting the buffer resilience. To estimate the optimal size of buffer resilience, we exploits an adaptive buffer resilience control scheme that minimizes both data buffer space and idle time of the processing elements based on directly measured sample path analysis. The simulation results show that the proposed scheme provides allowable approximation compared to the numerical results. Also, it is suitably efficient to apply for such a dynamic environment that cannot postulate the stochastic characteristic for the data transfer time, the data processing rate, or even an environment where the fluctuation of the both is presented.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.645-650
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• 2006

The heat transfer performance and energy transport ability are relatively high due to higher specific heat. Therefore, it can be used in fields such as heating, ventilating, air-conditioning, refrigeration and heat exchangers. In this study, liquid-cooling heat exchangers were designed and tested by varying geometry and operating conditions. In addition, liquid-cooling heat exchangers were tested to provide performance data for MPCM slurry. The liquid-cooling heat exchangers had twelve rectangular channels with flow paths of 1, 2, 4 and 12. Silicon rubber heaters were used to control the heat load to the heat exchanger. Heat input ranged from 293 to 800 W, and inlet temperatures of working fluid varied from 15S to $27^{\circ}C$. The standard deviation of surface temperature was strongly affected by the coolant of MPCM Slurry, All MPCM-cooling heat exchangers showed higher cooling performance than the water-cooling heat exchanger except one path channel heat exchanger.

• Earthquakes and Structures
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• v.12 no.6
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• pp.699-712
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• 2017

This study evaluates the effectiveness of a newly developed retrofitting scheme for masonry-infilled non-ductile RC frames experimentally and by numerical simulation. The technique focuses on modifying the load path and yield mechanism of the infilled frame to enhance the ductility. A vertical gap between the column and the infill panel was strategically introduced so that no shear force is directly transferred to the column. Steel brackets and small vertical steel members were then provided to transfer the interactive forces between the RC frame and the masonry panel. Wire meshes and high-strength mortar were provided in areas with high stress concentration and in the panel to further reduce damage. Cyclic load tests on a large-scale specimen of a single-bay, single-story, masonry-infilled RC frame were carried out. Based on those tests, the retrofitting scheme provided significant improvement, especially in terms of ductility enhancement. All retrofitted specimens clearly exhibited much better performances than those stipulated in building standards for masonry-infilled structures. A macro-scale computer model based on a diagonal-strut concept was also developed for predicting the global behavior of the retrofitted masonry-infilled frames. This proposed model was effectively used to evaluate the global responses of the test specimens with acceptable accuracy, especially in terms of strength, stiffness and damage condition.

• Journal of Korean Association for Spatial Structures
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• v.13 no.3
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• pp.45-55
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• 2013

The core aim of this paper is to empirically scrutinize a strength characteristic and ductility of the beam-column frame of reinforced with steel subjected to the cyclic lateral load. First and foremost, I the author embarks upon making four prototypes vis-$\grave{a}$-vis this research. Through this endeavour, the author has analysed cyclic behavior, fracture shape, ductility and energy dissipation of the normal beam-column frame and a beam-column frame of reinforced with steel. In addition, the survey has revealed the exact stress transfer path and the destructive mechanism in order to how much a beam-column frame of reinforced with steel has resistance to earthquake regarding all types of building, as well as school construction. To get the correct data, the author has compared the normal beam-column frame and three types of the beam-column frame of reinforced with steel following these works, the characteristic of cyclic behavior, destructive mechanism, ductility, and Energy dissipation of normal beam-column frame and a beam-column frame of reinforced with steel have been examined clearly.

• International Journal of Automotive Technology
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• v.8 no.5
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• pp.629-636
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• 2007

This paper describes the process of analyzing vehicle stiffness in terms of frequency band in order to improve vehicle handling. Vehicle handling and ride comfort are highly related to the systems such as suspension, seat, steering, and the car body design. In existing analytical processes, the resonance frequency of a car body is designed to be greater than 25 Hz in order to increase the stiffness of the body against idle vibration. This paper introduces a method for using a band with a frequency lower than 20 Hz to analyze how stiffness affects vehicle handling. Accordingly, static stiffness analysis of a 1g cornering force was conducted to minimize the deformation of vehicle components derived from a load on parts attached to the suspension. In addition, this technology is capable of achieving better performance than older technology. Analysis of how body attachment stiffness affects the dynamic stiffness of a bushing in the attachment parts of the suspension is expected to lead to improvements with respect to vehicle handling and road noise. The process of developing a car body with a high degree of stiffness, which was accomplished in the preliminary stage of this study, confirms the possibility of improving the stability performance and of designing a lightweight prototype car. These improvements can reduce the time needed to develop better vehicles.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.6
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• pp.58-63
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• 2016

This paper presents a study of heat dissipation away from the fuel combustion of a marine diesel engine. These engines are operated for long periods under high load conditions: so cooling systems are necessary for radiation and control of the high temperature levels. In the study, each component of the water cooling system was developed to achieve improvements in cooling and safety. Heat transfer considerations and arrangement design for the components were important and an intercooler and exhaust manifold incorporated. An optimization of the cooling water's flow path was achieved subject to the need for convenient maintenance. The 750Ps marine diesel engine was used for performance testing of the cooling system. The test results showed adequate cooling performance improvement.