• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.921-924
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• 2005

Diesel generator sets with resilient mounts often experience resonances by major excitations which come from diesel engine and their foundation with rigid body modes. Because their natural frequency is determined by moment of inertia and stiffness of resilient mount vibration problems are resolved by changing location and stiffness of resilient mounts. But the calculated natural frequencies are inaccurate due to uncertainty of the inertia and mount stiffness. So this result can be useless on the design stage. In this paper, the stiffness of mount is evaluated on result from mount stiffness test in laboratory and generator set vibration test and a simple calculation method for moment of inertia is proposed. Based on these data, the procedure to select optimized mount stiffness and location on the design stage is set up.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.04a
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• pp.188-193
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• 1996

The purpose of resilient mounting for marine engine is to prevent noise and ship damages caused by engine vibration. Although many researches for the resilient mounting system have been carried out, these results have limit to apply on the marine engine systems. Because marine engine generally have low speed operating range and have to consider misfiring condition. In this paper, we studied the effect of engine's misfiring on the resilient mounting systems. And the influences of design parameters, such as dynamic characteristics and location angles of resilient rubber mountings, were also examined on the single and double resilient mounting systems.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.13-16
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• 2008

Floor impact sound insulation performance of floor resilient materials produced by T company were tested in T company's lab. The results of this study can be summarized as follows. 1) Thickness changes of materials or arrangement order of materials are not much influential in floor impact sound insulation performance. 2) PS sheet and PP sheet upper part location is optimal association in reducing sound at low frequencies. 3) Composition of different form resilient materials' performance is better than that of similar form composition's.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.3
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• pp.69-78
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• 1993

A testing system has been developed to evaluate the seasonal variation of the resilient modulus of granular subgrade soils. Two sites were successfully instrumented with soil moisture-temperature cells to monitor over a period of one year, the field temperature and moisture content underneath the pavement. Multiple regression equations were developed to determine the resilient modulus under environmental conditions. It is noted that the use of the effective resilient modulus at the location of the Average Depth of Significant Stress (ADSS) provides a reasonable basis for determining subgrade properties. In addition, a theoretical model has been developed to predict the resilient modulus due to the change of temperature and moisture condition.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.942-947
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• 2002

In this study, reduction of airborne and structure-borne noise of naval ship pump is presented. Since piping system arrangement such as valve location, flexible joint, pipe diameter and elbow location, discharge basin affect greatly on the noise measurement, care must be taken to minimize the unnecessary noise from the piping system. It is shown that structure-borne noise of the motor with single resilient mount system exceeds criterion. Therefore, it is concluded that double resilient mount system is inevitable. Two kinds of mount is studied for upper mount; spring and rubber type. Although both mounts show good performance at low frequency including rpm frequency, 63Hz, spring mount is found to be inadequate at high frequency, because spring coil acts as a path for SBN.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.1
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• pp.53-61
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• 2015

This paper reports the test results of the floating floor system used to reduce the floor noise of apartment buildings. Recently, many soft resilient materials placing between the reinforced concrete slab and finishing mortar are used. The resilient material should not only reduce the floor impact sound vibration from the floor but also support the load on the floor. Thus, even if soft resilient materials satisfy the maximum limitation of light-weight impact sound and heavy-weight impact sound, these materials may not support the load on the floor. The experimental program involved conducting sixteen sound insulation floating floor specimens. Three main parameters were considered in the experimental investigation: resilient materials, loading location, and layers of floor. Experimental results indicated that the stiffness of resilient material significantly influenced on the structural behavior of floating floor system. In addition, the deflection of the floating concrete floor loaded at the side or coner of the specimen was greater than that of the floor loaded at the center of the specimen. However, the aerated concrete did not effect on the cracking strength of floating floor system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.227-230
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• 2011

In this paper, we are proposed ECOPS(Energy Conserving optimal Path Schedule) algorithm that according to ALPS(Ad hoc network Localized Positioning System) algorithm the location information is received and the new head node is selected considering the energy efficiency. The proposed algorithm follows RODMRP(Resilient Ontology-based Dynamic Multicast Routing Protocol) structure, that is the hierarchic cluster structure. And by using the location information of the node, it maintains the cluster which the energy is efficient with the production. It increases the life time of the total routing structure.

• Journal of Communications and Networks
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• v.15 no.2
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• pp.153-163
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• 2013

In recent years, more and more researches have been focusing on trust management of vehicle ad-hoc networks (VANETs) for improving the safety of vehicles. However, in these researches, little attention has been paid to the location privacy due to the natural conflict between trust and anonymity, which is the basic protection of privacy. Although traffic safety remains the most crucial issue in VANETs, location privacy can be just as important for drivers, and neither can be ignored. In this paper, we propose a beacon-based trust management system, called BTM, that aims to thwart internal attackers from sending false messages in privacy-enhanced VANETs. To evaluate the reliability and performance of the proposed system, we conducted a set of simulations under alteration attacks, bogus message attacks, and message suppression attacks. The simulation results show that the proposed system is highly resilient to adversarial attacks, whether it is under a fixed silent period or random silent period location privacy-enhancement scheme.

• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.4
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• pp.432-440
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• 2015

UGVs(Unmanned Ground Vehicles) are robots that can substitute humans in reconnaissance operations of potentially dangerous and contaminated sites. Currently, there have been active research on utilizing UGVs in military environments. Much resrach has been focused on exploiting the weakness of topology-based routing and instead utilize location-based routing for the networking of UGVs. It is generally assumed that location-based routing methods can fully utilize the location information gained from GPS. However, this may not be possible in tactical environments due to enemy GPS jamming and LOS(Line of Sight) limitations. To solve this problem, we propose a location-based routing scheme utilizing low control message that can calibrate the location information using GPS information as well as location of neighboring UGV, movement direct and speed information. Also utilizing topology-based routing scheme to solve incorrect location information in GPS jamming region.

• Journal of Digital Contents Society
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• v.18 no.3
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• pp.567-575
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• 2017

Location-based services play an important role in many applications such as disaster warning systems and recommendation systems. These applications often require not only location information (e.g., name, latitude, longitude, etc.) but also the impact of events (e.g., earthquake, typhoon, etc.) on locations. Recently, to provide the impact of an event on a location, how to calculate location trustiness by using multimodal information such as earthquake information and disaster sensor data is researched. In the previous approach, the linear decrement of impact value of an event is applied to obtain the location trustiness of a specific location. In this paper, we propose a new approach to enrich location trustiness, that is, the impact of an event on a location, by using social media information additionally. Firstly, we design a collecting system for earthquake information and social media data. Secondly, we present an approach of location trustiness calculation based on earthquake information. Finally, we propose a new approach to enrich location trustiness by augmenting the trustiness in spatially distributed manner based on social media.