• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.55-56
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• 2015

A smart meter is a kind of electronic meters that measures and records consumption of electric energy in intervals of an hour or less and transmits that information to the remote places. AMI provides two-way communication path between utilities and consumers and should be able to support smart grid's new functionalities such as demand-response actions and real time pricing. The main objective of this paper is to provide a new diagnosis method and system for testing of smart meters in AMI neighborhood area network.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.135-140
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• 2011

The battery pack, a main component of NEV(Neighborhood Electric Vehicle), needs cooling system when it is charging or discharging to prevent the degradation of the battery charging efficiency. The purpose of this study is to analyse the effects of cooling methods, changing positions of inlet and outlet and changing area ratios of inlet and outlet. It has been observed that in the point of uniform cooling suction from the exit side is more efficient than blowing from the inlet. And there is a suitable inlet/outlet area ratio in maximizing the mass flow rate. The numerical analyse using a commercial code STAR-CCM+ version 4.02 were used for the study.

• Journal of the Korean Mathematical Society
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• v.47 no.5
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• pp.1001-1015
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• 2010

Let M be a $C^{\infty}$ real hypersurface in $\mathbb{C}^{n+1}$, $n\;{\geq}\;1$, locally given as the zero locus of a $C^{\infty}$ real valued function r that is defined on a neighborhood of the reference point $P\;{\in}\;M$. For each k = 1,..., n we present a necessary and sufficient condition for there to exist a complex manifold of dimension k through P that is contained in M, assuming the Levi form has rank n - k at P. The problem is to find an integral manifold of the real 1-form $i{\partial}r$ on M whose tangent bundle is invariant under the complex structure tensor J. We present generalized versions of the Frobenius theorem and make use of them to prove the existence of complex submanifolds.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.724-729
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• 2003

Installing vibration isolation in structures, such as structures adjacent to subways, may be delicatebecause of the proximity with the vibration source or because of the wave propagation path. This paper discusses on method that install isolation Pads on underground walls as a part of the vibration mitigation system, and also on its efficiency, The proposed method is proven to affect significantly the distribution of acceleration in the neighborhood of the structure and to reduce efficiently the maximum amplitude of the vibration. It is also seen that installing isolating pads until the depth of the foundations and deeper is more efficient than installing such device separately from the structure. This Study being limited to the comparison of installation methods, further Studies considering the thickness, stiffness and other parameters should be required.

• Tribology and Lubricants
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• v.18 no.5
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• pp.333-338
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• 2002

Results of theoretical investigations on acoustical properties of hydrodynamic journal bearings are presented. Nonlinear analysis including rotor imbalance is performed for a rotor-bearing system in order to obtain acoustical properties of hydrodynamic journal bearings. Furthermore, a cavitation algorithm, implementing the Jakobsson-Floberg-Olsson boundary condition, is adopted to predict cavitation regions in a fluid film. Acoustical properties of hydrodynamic journal bearings are identified through frequency analysis of oil pressure fluctuation calculated from the nonlinear transient analysis. The results show that the acoustical frequency spectra of the fluid film are pure tone spectra, containing the frequency of the shaft rotation and its super-harmonics. The analysis also shows that super-harmonics are predominant at the neighborhood of the fluid film reformation and rupture regions.

• Journal of The Korean Astronomical Society
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• v.27 no.2
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• pp.159-175
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• 1994

We have mapped the whole extent of a dark cloud Lynds 1251 in the emission of the J=1-0 transitions of $^{12}CO\;and\;^{13}CO$ using FCRAO's fifteen-beam array receiver in high angular resolution of 50'. We have derived physical parameters of L1251, discussed three different mass estimate techniques, and obtained a large range of mass, 600 to $6,000M_\bigodot$, depending on the techniques. The factor of 10 discrepancy between the virial and LTE masses is much larger than expected based on the uncertainties residing in two methods. The large virial mass may reflect the fact that L1251 is not gravitationally bound system as in the case of dark clouds in solar neighborhood. Two outflows are affecting the dynamics of cloud significantly but not enough to reshape the whole extent of the cloud. The small cloud, 'Stripe', which is apparently connected with main cloud, is not likely to be associated with L1251. The velocity gradient composed on this small cloud may be driven by other unknown sources. It is found that L1251 cloud itself is very quiescent except the two bipolar outflow regions.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.720-723
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• 2017

돼지 호흡기 질병은 돈사에 막대한 경제적 손실을 초래하는 질병들 중 하나이다. 본 논문에서는 저비용으로도 구축이 가능한 소리 센서 기반의 돼지 호흡기 질병 탐지 시스템을 제안하며, 특히 잡음 환경에서도 강인한 시스템의 구성에 초점을 두었다. 제안하는 시스템은 먼저, 돈사 내의 소리 센서로부터 취득한 돼지 소리를 2차원 회색조 이미지로 변환한다. 이후, 잡음에 강인한 성능을 보이는 Dominant Neighborhood Structure(DNS) 알고리즘을 이용하여 질감정보를 추출한다. 마지막으로, 이미지 분류에서 그 성능이 이미 입증된 딥러닝의 대표적 모델인 Convolutional Neural Network(CNN)에 사용하여 돼지 호흡기 질병을 탐지 및 분류한다. 실제 국내 돈사에서 취득한 돼지 소리를 이용하여 제안하는 시스템의 성능을 실험적으로 검증한 바 96%가 넘는 안정적인 시스템임을 확인하였다.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.1
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• pp.5-11
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• 2010

An adaptive formation control approach is proposed for nonhonolomic multiple mobile robots considering unknown slipping and skidding. It is assumed that unknown slipping and skidding effects are bounded by unknown constants. Under this assumption, the adaptive technique is employed to estimate the bounds of unknown slipping and skidding effects of each mobile robot. To deal with the skidding effect included in kinematics, the dynamic surface design approach is applied to design a local controller for each mobile robot. Using Lyapunov stability theorem, the adaptation laws for tuning bounds of slipping and skidding are induced and it is proved that all signals of the closed-loop system are bounded and the tracking errors and the synchronization errors of the path parameters converge to an adjustable neighborhood of the origin. Finally, simulation results are provided to verify the effectiveness of the proposed approach.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.4
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• pp.105-117
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• 1998

In this paper, the general formula of disparity estimation based on Bayesian Maximum A Posteriori (MAP) algorithm is derived and implemented with simplified probabilistic models. The probabilistic models are independence and similarity among the neighboring disparities in the configuration.The formula is the generalized probabilistic diffusion equation based on Bayesian model, and can be implemented into the some different forms corresponding to the probabilistic models in the disparity neighborhood system or configuration. And, we proposed new probabilistic models in order to simplify the joint probability distribution of disparities in the configuration. According to the experimental results, the proposed algorithm outperformed the other ones, such as sum of swuared difference(SSD) based algorithm and Scharstein's method. We canconclude that the derived formular generalizes the probabilistic diffusion based on Bayesian MAP algorithm for disparity estimation, and the propsoed probabilistic models are reasonable and approximate the pure joint probability distribution very well with decreasing the computations to 0.01% of the generalized formula.

• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2193-2196
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• 1998

Cellular automata are dynamical systems in which space and time are discrete, where each cell has a finite number of states and updates its states by interactive rules among the cell-neighborhood. From the characteristics of self-reproduction and self- organization, it is possible to create a neural network which has the specific patterns or structures dynamically. CAM-Brain is a kind of such neural network system which evolves its structure by adopting evolutionary computations like genetic algorithms (GA). In this paper, we suggest the evolution strategies for the structure of neural networks based on cellular automata.