• International Journal of High-Rise Buildings
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• v.11 no.4
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• pp.347-362
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• 2022

Current vibration serviceability assessment criteria for wind-induced vibrations in tall buildings are based largely on human 'perception' thresholds which are shown not to be directly translatable to human 'acceptability' of vibrations. There is also a considerable debate about both the metrics and criteria for vibration acceptability, such as frequency of occurrence or peak vs mean vibration, and how these might vary with the nature of the vibration. Furthermore, the design criteria are necessarily simplified for ease of application so cannot account for a range of environmental, situational and human factors that may enhance or diminish the impact of vibrations on serviceability. The dual-site VSimulators facility was created specifically to provide an experimental platform to address gaps in understanding of human response to building vibration. This paper considers how VSimulators can be used to inform general design guidance and support design of specific buildings for habitability, in terms of vibration, which allow engineers and clients to make informed decisions with regard to sustainable design, in terms of energy and financial cost. This paper first provides a brief overview of current vibration serviceability assessment guidelines, and the current understanding and limitations of occupants' acceptability of wind-induced motion in tall buildings. It then describes how the dual-site VSimulators facility at the Universities of Bath and Exeter can be used to assess the effects of motion and environment on human comfort, wellbeing and productivity with examples of how the facility capabilities have been used to provide new, human experience based experimental research approaches.

• International Journal of Industrial Entomology and Biomaterials
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• v.5 no.2
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• pp.141-151
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• 2002

The success of sericulture industry in India is mainly attributed to the well-planned annual sericultural activity and the systematic implementation of pest preventive and control measures. The insect spectrum of silkworm and its food plants is complex and plays a major role in limiting the production of silk. Insects cause extensive damage to plant whereas predators and parasites either kill the silkworm larvae or force them to spin flimsy cocoons. Unilateral control measure against this pest is mainly based on the use of synthetic organic insecticides. Though these approaches initially paid rich dividends, the undesirable consequences soon surfaced. Insecticide induced resurgence of gall midges, leafhopper, leaf roller, secondary pest out breaks and development of pest biotypes has led to realization of Integrated Pest Management in sericulture. Various components of IPM, viz. Host plant resistance, cultural practices, biological control, chemical control and integrating them at various technological levels have been studied. Sources of host plant resistance have been identified for some of the major insect pests. High yielding mulberry variety has been propagated and their resistances towards major pests have been recorded. Cultural practices like pruning, pollarding, judicious use of nitrogen, optimum spacing and weed management have preyed to be the powerful tools in containing pests. Natural control over the pest population build- up exerted by the wide range of parasitoids, predators and pathogens has been well documented with identification of natural enemies and studies on their potential. Augmentation, through inoculation or inundative releases of parasitic arthropods, is the most direct way of increasing the numbers of these beneficials in sericulture.

• Structural Engineering and Mechanics
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• v.16 no.6
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• pp.675-693
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• 2003

In order to consider the modified seismic response of framed structures in the presence of masonry infills, proper models have to be formulated. Because of the complexity of the problem, a careful definition of a diagonal pin-jointed strut, able to represent the horizontal force-interstorey displacement cyclic law of the actual infill, may be a solution. In this connection the present paper shows a generalized criterion for the determination of the ideal cross-section of the strut mentioned before. The procedure is based on the equivalence between the lateral stiffness of the actual infilled frame scheme during the conventional elastic stage of the response and the lateral stiffness of the same frame stiffened by a strut at the same stage. Unlike the usual empirical approaches available in the literature, the proposed technique involves the axial stiffness of the columns of the frame more than their flexural stiffness. Further, the influence of the bidimensional behaviour of the infill is stressed and, consequently, the dependence of the dimensions of the equivalent pin-jointed strut on the Poisson ratio of the material constituting the infill is also shown. The proposed approach is extended to the case of infills with openings, which is very common in practical applications.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.529-533
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• 2005

A railway catenary system which supplies a train with electric power is an important system in determining the maximum speed of an electric train. However, a pantograph could be separated from a contact wire because of reciprocal action between a pantograph with constant upward force and a catenary system. The contact loss of a pantograph-catenary system is mainly affected by the dynamic characteristics of damping and wave propagation velocity of contact wire. For increasing speed of an electrical train, it is necessary to establish the techniques to identify the modal parameter of a catenary system through experiment. However, it is difficult to decouple each mode and to extract respect ive damping rat io since a catenary system has an extremely high modal density. For this reason, mode decoupling process to identify modal parameters is a principal technique in analyzing a catenary system. In this paper, the damping extract ion method for a catenary system using the continuous wavelet transform is discussed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.9
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• pp.972-981
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• 2008

The blower which is installed in a FCEV(fuel cell electric vehicle) may cause noise due to misalignment and unbalance of mechanical components that rotate at high speed. One of the key points in efforts to minimize the noise radiation from a blower is the knowledge of the main radiating component and the relation between the surface vibration of a blower and the sound pressure. In this research, the blower model is developed based on FEM(finite element method). FE(finite element) model is reliable by correlation of frequencies and MAC(modal assurance criterion) values between EMA(experimental modal analysis) and FEA(finite element analysis). This model is applied to predict the vibration of a blower by using inverse force identification method and predict the radiating noise by using BEM(boundary element method). Comparing the frequencies of resonance and those mode shapes between EMA and FEA, a structural modification of the FE model is evaluated for reducing the parameters of the blower noise.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.869-874
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• 2002

Hermetic rotary compressor is one of the most important components for air conditioning system since it has a great effect on both the performance and the noise and vibration of the system. Noise and vibration of rotary compressor is occurred due to gas pulsation during compression process and unbalanced dynamic force. In order to reduce noise and vibration, It is necessary to identify sources of noise and vibration and effectively control them. Many approaches have been tried to identify noise sources of compressor. However, compressor noise source identification has proven to be difficult since the characteristics of compressor noise are complicated due to the interaction of the compressor parts and gas pulsation. In this work, Statistical Energy Analysis has been used to trace the energy flow in the compressor and identify transmission paths from the noise source to the sound field.

• Journal of KSNVE
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• v.1 no.2
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• pp.121-128
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• 1991

In order to use viscoelastic materials efficiently for noise and vibration control, or th qualify newly developed materials, knowledge of the Young' s modulus and loss factor is essemtial. These material properties, the so-called complex Young' s modulus, are frequently treated as dynamic charicteristics because of their dependence upon the frequency. Many techniques have been developed and verified for measuring complex Young' s modulus of viscoelastic materials. Among them, the impedance method is preferable in order to obtain the frequency information in detail. In this method, a cylindrical or prismatic specimen is excited into longitudinal harmonic vibration at one end, the other being fixed, and the resulting force is measured at the driving or fixed end. The amplitude ratio of the two signals and phase angle between them are then used to compute the material properties using various mathematical models. In this paper, the impedance method is investigated theoretically and experimentally. A way to determine the specimen geometry which is most appropriate for the identification of complex Young' s modulus using the lumped mass model is presented and discussed. Then experimental results supporting the theoretical predictions are presented.

• The Journal of the Korea Contents Association
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• v.17 no.7
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• pp.571-578
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• 2017

In order to approach information system through smart device and pc, user has to authenticate him or herself via user authentication. At that time when user tries reaching the system, well-used user authentication technologies are ID/PW base, OTP, certificate, security card, fingerprint, etc. The ID/PWbased method is familiar to users, however, it is vulnerable to brute force cracking, keylogging, dictionary attack. so as to protect these attacks, user has to change the passwords periodically as per password combination instructions. In this paper, we designed and implemented a user authentication system using smartphone's USIM without using password while enhancing security than existing ID / PW based authentication technology.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.7
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• pp.106-111
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• 1989

A new EMG signal processing algorithm for SMUAP pattern classification is proposed. It checks the combination and regularity of ISI using a spike counter as a decision making routine, and performs SMUAP waveform alignment in frequency domain and selects spikes through FIR filtering. As a result, with the EMG signals recorded during 5 seconds at 10-50% MVC force level, the SMUAP ranged from five to nine units were classified and identification rate is greater than 55 percent using a concentric needle electrode. In the IBM PC/AT the processing time typically required 2 minutes.

• Structural Engineering and Mechanics
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• v.54 no.2
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• pp.199-219
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• 2015

This paper presents the non-destructive evaluation of a high-speed railway bridge using train-induced strain responses. Based on the train-track-bridge interaction analysis, the strain responses of a high-speed railway bridge under moving trains with different operation status could be calculated. The train induced strain responses could be divided into two parts: the force vibration stage and the free vibration stage. The strain-displacement relationship is analysed and used for deriving critical displacements from theoretical stain measurements at a forced vibration stage. The derived displacements would be suitable for the condition assessment of the bridge through design specifications defined indexes and would show certain limits to the practical application. Thus, the damage identification of high-speed railways, such as the stiffness degradation location, needs to be done by comparing the measured strain response under moving trains in different states because the vehicle types of high-speed railway are relatively clear and definite. The monitored strain responses at the free vibration stage, after trains pass through the bridge, would be used for identifying the strain modes. The relationship between and the degradation degree and the strain mode shapes shows certain rules for the widely used simply supported beam bridges. The numerical simulation proves simple and effective for the proposed method to locate and quantify the stiffness degradation.