• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.5
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• pp.123-130
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• 2001

The purpose of this paper is to reduce the level of idling vibration on a steering wheel. In some cases, vibration on steering wheel is amplified due to the resonance between the first natural frequency of T-beam and engine idling speed. Using SDM(structural dynamic modification) technique, T-beam is redesigned to reduce its vibration. This paper used FRF(frequency response function) synthesis technique which is entirely dependent on experiment. But this method requires lots of test efforts to enhance its reliability of design. While combining this method with an analytic method. the experimental burden, the major drawback of FRP synthesis method, can be considerably relieved. Using ana1ytic sensitivity analysis, some effective modification regions are preliminarily chosen as candidate Positions where SDM can be applied to modify T-beam\`s dynamic characteristics.

• Journal of the korean Society of Automotive Engineers
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• v.5 no.2
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• pp.15-20
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• 1983

The nature and the sources of sound in cars is discussed in the light of many previous works, and the importance of the system resonances inside cars is suggested. An investigation of a 'boom' problem in a small size passenger car is described. It was established that the 'boom' frequencies coincided with engine firing frequency and also with several system resonances. To find out main transmission path of the noise to the car interior, various possible sources were eliminated from the investigation by means of simple modification to the vehicle. Data on the structural modes of the body, and the acoustic modes of the passenger compartment at various forcing cases were obtained to provide better understanding of the problem. It was found that the acoustic resonance responsible for the boom was controlled largely the bending motion of the floor. To investigate the effect of the structural modification to the acoustic response, center floor of the car was reinforced. a great reduction of the noise inside the car especially at the offending speed range, was achieved by this modification.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.354-359
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• 2012

Improvement of structure-borne noises in the vehicle compartments has been one of the primary concerns in the development of vehicles. The booming is an annoying low frequency interior noise and vibration in vehicle. But it is difficult to reduce the structure-born booming noise in traditional method - trial and error within the shorten development schedule. So in present, the structure dynamic modification (SDM) method helpful to predict the effect of the local mass, stiffness, and damping is introduced. So in order to reduce the interior booming noise, the SDM was performed, and verified with modal test result. It was shown that the interior booming noise was reduced as predicted.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.12
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• pp.1145-1151
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• 2007

In this paper, vibration sources of an electric forklift are identified and the forklift vibrations are reduced by structural modification. For vibration identification, vibration signals are measured by an accelerometer when the forklift is moving. These signals are presented in a waterfall plot in order to find the dependency of frequency components on the forklift speed. It is found that main vibration source is tire pattern excitation. From some experiments and finite element analyses, it is also found that resonances occur because the natural frequencies of the forklift exist in usual driving speed range. To shift the natural frequencies outside the driving speed range, the connection parts between main body and loader are modified to increase stiffness. It is verified that considerable amount of vibration are reduced by the structural modification.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.223-226
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• 2007

In current specification, modification factor(B) for web-tapered beam is used to account for the stress gradient and the restraining effect for adjacent spans. However, because these effects are considered together in modification factor, this paper revaluate the accuracy of the modification factor used in current specification. Also this paper investigate the flexural torsional buckling strength of laterally fixed thin-walled arch with doubly symmetric section using the analytical and numerical method. From this investigate the concept of effective length to consider the out-of-plane boundary condition for straight column or beam is not applicate for the flexural-torsional buckling of laterally fixed arches.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.4
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• pp.53-63
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• 2007

Seismic design codes are developed mainly based on the observation of the behavior of structures in the high seismicity regions where structures may experience significant amount of inelastic deformations and major earthquakes may result in structural damages in a vast area. Therefore, seismic loads are reduced in current design codes for building structures using response modification factors which depend on the ductility capacity and overstrength of a structural system. However, structures in low seismicity regions, subjected to a minor earthquake, will behave almost elastically because of the larger overstrength of structures in low seismicity regions such as Korea. Structures in low seismicity regions may have longer periods since they are designed to smaller seismic loads and main target of design will be minor or moderate earthquakes occurring nearby. Ground accelerations recorded at stations near the epicenter may have somewhat different response spectra from those of distant station records. Therefore, it is necessary to verify if the seismic design methods based on high seismicity would he applicable to low seismicity regions. In this study, the adequacy of design spectra, period estimation and response modification factors are discussed for the seismic design in low seismicity regions. The response modification factors are verified based on the ductility and overstrength of building structures estimated from the farce-displacement relationship. For the same response modification factor, the ductility demand in low seismicity regions may be smaller than that of high seismicity regions because the overstrength of structures may be larger in low seismicity regions. The ductility demands in example structures designed to UBC97 for high, moderate and low seismicity regions were compared. Demands of plastic rotation in connections were much lower in low seismicity regions compared to those of high seismicity regions when the structures are designed with the same response modification factor. Therefore, in low seismicity regions, it would be not required to use connection details with large ductility capacity even for structures designed with a large response modification factor.

• Journal of the Korean Society of Costume
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• v.55 no.2 s.92
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• pp.45-57
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• 2005

The creative fashion design is the technique which ran be obtained through the structural analysis of the relationship between principle, element-combination and idea-expression. In the research, as the results of theoretical survey of design structure and idea-expression, the structural and subjective designs are classified and defined: a. the structural design is analyzed with the existing examples based on the combinational Idea-expression of the O.C.L method, and b. the subjective design is also analyzed connecting the real examples to Cordon method, Synetic method, Association method, and expansive idea-expression-method obtained by the Experiences of Geometrical Combinations. The research can be summarized as follows: 1. The creative fashion design which emphasizes the geometrical structure utilizes the modification method whirh combines the shapes and constructs extraordinary structural beauty coming from the complex structural principle, that is, emphasis and balance. 2. The creative fashion design which emphasizes specific subjects utilizes the modification method which mimics representative and plastic resemblances and constructs symbolic structural beauty coming from the simple structural principle, that is, material elements.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.4
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• pp.209-216
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• 2003

Load carrying capacity evaluation is very important element in maintenance of bridge. There are several reasons about differences in deflection caused by loading test and structural analysis. Especially when we do modeling uniformly without considering real structural characteristics of support, this problem can be more deepened. This computes modification factor high so we may evaluate the load carrying capacity more than fact. In this study, we do structural analysis nearing real structure with negative bending moment of support that computes considering structural characteristics of support, and then evaluate load carrying capacity.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.439-440
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• 2012

New analysis methods complement classical approaches in the vehicle NVH development by reducing and accelerating iteration steps to obtain a target sound. Therefore, tools are required that allow an integrative approach of sound engineering and structural analysis and enable a precise simulation and modification based on measured data. The Response Modification Analysis (RMA) is such a hybrid solution, which provides indications of relevant transfer paths taking into account the sensitivity of response channels to modifications of reference channels.

• Archives of Pharmacal Research
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• v.2 no.1
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• pp.71-78
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• 1979

Since the introduction of aspirin as a therapeutic agent in 1899, there have been numerous attempts at the improvement of its therapeutic value through molecular modification. These endeavors have centered mainly around the following two approaches : (a) improvement of the potency by introduction of a suitable group or groups on the benzene ring; and (b) modification of the carboxylic acid group, which is thought to be an immediate cause of the irritant effect.