• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.6 s.99
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• pp.738-748
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• 2005

The ship radiated noise level fluctuates by the difference of interference and reverberation according to measurement methods and environmental conditions. These phenomena cause error of the source level estimation even in the same environment conditions. This paper describes a quantitative analysis and a reduction method for an error value to the source level estimation in spatial and temporal interference environment. The design criteria of the radiated noise measurement array composed of omni-directional hydrophones and the source level accuracy in the deep water range are given. The source level accuracy in the shallow water range is also derived based on the statistical model of the multiple reflection paths. The results are verified using the water tank experiment and the sea trial.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.6
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• pp.521-527
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• 2010

This article presents a method to calculate the sound radiation of transmission gearbox housing by using Helmholtz integral. Rayleigh integral is used to verify the method. Half-space radiation is considered because the actual gearbox housing is on hard place like concrete. For optimization, orthogonal array is used as a fractional factorial design method. Sound Radiation is calculated with simple source like plate and sphere shape, then actual gearbox BEM model is applied to the method.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.2
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• pp.245-254
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• 2017

In this paper, deployment dynamics of large-scale flexible solar arrays with deployable mast is investigated. The adopted solar array system is introduced firstly, then kinematic description and kinematic constraint equations are deduced, and finally, dynamics equation of the system is established by the Jourdain velocity variation principle and a new method to deal with topology changes of the deployable mast is introduced. The dynamic behavior of the system is studied in detail. Simulation results indicate that the proposed model is effective to describe the deployment dynamics of the solar arrays and that the introduced method is applicable for topology changes.

• Structural Engineering and Mechanics
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• v.21 no.1
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• pp.53-66
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• 2005

When a large number of identical cylinders are placed in an array with equal separation distance, near-resonant phenomena may occur between cylinders at critical frequencies, and cause large wave forces on each element of the array. In this paper, 64 truncated circular cylinders arranged in 4 rows and 16 columns are considered to check occurrence of near-resonant phenomena and performance of theoretical predictions based on the potential flow. Experiments are conducted in head waves to measure the wave elevation along the longitudinal centerline of the model, and measured results are compared with numerical ones. Attention is focused on the spatial variation of the wave amplitude around the first near-trapped-mode frequency.

• 한국연소학회:학술대회논문집
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• 2001.11a
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• pp.63-71
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• 2001

The objective of this work is to elucidate the details of two key factors dominating the droplet buring behavior in sprays : droplet-droplet interaction and convective flow. The combustion of a one-dimensional linear droplet array with a convective flow has been studied. A one-step, second order model was employed to simulate the chemical reaction in the combustion process. Results for droplet arrays burning at two Reynolds numbers, 50 and 100, two horizontal droplet spacings, 5 and 11 radii, and two vertical droplet spacing, 2 and 4 radii, were obtained. The results indicate the droplet burning behavior is affected by Reynolds number, droplet-droplet spacing, and the relative location of droplets in the array. Droplet-droplet interaction was found to be strong for arrays with smaller droplet spacing.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.3
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• pp.591-596
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• 2001

In recent years, interest in microstrip antenna has been increasing, primarily because of their low profile, and light weight and relative cheapness. In this paper we present a theoretical analysis of the circular Patch array antenna. The theory is based on cavity model analysis. The calculated results are compared with experimental results showing good agreement. A $8\times8$ array antenna at 12GHz frequency band is designed and tested. The experimental results of relatively good characteristics show that its maximum rain is 24.8(dB), and its impedance bandwidth is 120MHz$(VSWR\leq2)$.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.2
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• pp.364-372
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• 1994

Theoretical method for analyzing the radiation pattern of cross-type 5-patch rectangular microstrip antenna is presented. The equivalent circuit of the array antenna is represented by the conventional transmission line model and the radiation admittance derived from the equivalent circuit of the slitted parallel-plate waveguide filled with a dielectric. The calculated results for the radiation pattern are compared with the measured values.

• Journal of Power Electronics
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• v.10 no.3
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• pp.320-327
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• 2010

In this paper, multiple offshore wave energy converters with different output characteristics are connected to one power distribution substation. The connection between the power take-off of the different wave energy converters and the electrical power transmission system is presented in order to investigate whether multiple wave energy converters can augment energy yield and improve network integration capabilities. Moreover, the model of an array of wave energy converters is developed with the goal of analyzing the effects of the offshore wave farm on the electrical network to which it is connected. It is also developed to ensure that the electricity generated by the array is sufficiently controllable, and of a quality that can be integrate into the electricity supply network without unduly increasing the cost of connection, production or delivery.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.123-126
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• 2005

The IEEE 1451.4 standards defines an architectural model for interfacing smart transducers for sensors & actuators. This standard allows analogue transducers to communicate their identification and calibration data in a digital format. A digital format is called TEDS(transducer electronic data sheet). However, the standard template of IEEE 1451.4 TEDS do not supports gas sensors to use in electronic nose system, such as array sensors. In this paper, a solution to standardize sensors for electronic nose systems is presented.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.45.4-45
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• 2002

In EIT, an array of disjoint electrodes is attached on the boundary of the object and a set of small alternating electrical currents is injected into the object through these electrodes, and then the corresponding set of voltages is measured on the same array of the electrodes. The objective in EIT is to estimate the resistivity distribution inside the object based on the set of measured voltages and injected currents. In this paper, we proposed a new dynamic EIT reconstruction scheme based on the interacting multiple model (IMM) algorithm. The main contribution of the proposed scheme is that multiple models are employed for the state evolution to get around the modeling uncertainty. Extensi...