• Journal of Biosystems Engineering
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• v.18 no.1
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• pp.21-29
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• 1993

The purpose of this study was to develope a potato combine which can be attached to and controlled by three-point hitch of tractors. A vibrating mechanism was designed and constructed to dig potatoes, and to evaluate the effects of vibration on the potato harvesting performance of the test machine, potato separation from soil, harvesting loss, and damage to the potatoes. Three types of potato pick-up mechanisms were constructed and tested. Digging performance and material flow on the blade were improved as the vibrating amplitude and frequency increased and as the travel speed decreased. The sum of unrecovered and damaged potatoes was up to 7.8%. Three pick-up devices were not found to be useful by failing to elevate about 30% of dug potatoes to a given height.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.10C
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• pp.844-850
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• 2008

This paper stated the proposed algorithm to certify the characteristics of artificial explosion sounds traveled through underground bedrock medium. Artificial explosion that travel through underground bedrock had an attenuation within high frequency bands in increase of a distance with multiple transmission paths phenomenon and inhomogeneity of geological status. In this paper, explosion experiment was made in underground tunnel to verify efficiency of proposed algorithm. The could certify the characteristics of artificial explosion sounds as extracted and numerically quantified the characterized parameter with collected sound sample that traveled through underground bedrock channel.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1997.04a
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• pp.67-76
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• 1997

The seismic records of the main shock and two after shocks of the Yeongwol Earthquake are studied based on the phsase analysis. The travel time curves with 12 different possible phases are constructed to analysis the phases of the records. which were provided by KIGAM seismic network. The results of phase analysis show that 1) The main shock (Ms=4.5) shows clear Pn phase but two after shocks (Ms=4 and Ms=2.5) do not show Pn phase. 2) The Pg or PmP phases look as first arrival phase in the after shock records whose edicental distance is smaller or larger than 150 km. 3) It is very difficult to identity the phases related to the Conrad discontinuity even if the Conrad discontiuity arrival exists. 4) The record of GRE station located outside of the Kueongsan Basin shows different arrival time of Pn phase, P-S duration time and frequency compared with those of the other stations located within the Kyeongsan Basin.

• Smart Structures and Systems
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• v.6 no.9
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• pp.1079-1105
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• 2010

Railway transport of goods and passengers is effective in terms of energy conservation and travel time savings. Safety and ride quality have become important issues as train speeds have increased. Due to increased speeds, minor damage to railway structures and abnormal interactions between trains and structures have given rise to increasingly serious accidents. Therefore, structural health and operational conditions must be monitored continuously in all service environments. Currently, various health and operation management systems are being developed and these are reducing both maintenance frequency and costs associated with disassembly. In this review, major damage and malfunctions and their locations are first analyzed based on numerous references. Then advanced train health and operation management technologies are classified into wayside detection methods and advanced integrated sensor methods and their operating principle and functions are reviewed and analyzed.

• Journal of Ocean Engineering and Technology
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• v.18 no.2
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• pp.10-17
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• 2004

In this research, a numerical simulation for the acoustic sounds around a two-dimensional circular cylinder in a uniform flaw was developed, using the finite difference lattice Boltzmann model. We examine the boundary condition, which is determined by the distribution function concerning density, velocity, and internal energy at the boundary node. Pressure variation, due to the emission of the acoustic waves, is very small, but we can detect this periodic variation in the region far from the cylinder. Daple-like emission of acoustic waves is seen, and these waves travel with the speed of sound, and are synchronized with the frequency of the lift on the cylinder, due to the Karman vortex street. It is also apparent that the size of the sound pressure is proportional to the central distance to the circular cylinder. The lattice BGK model for compressible fluids is shown to be a powerful tool for the simulation of gas flaws.

• Computational Structural Engineering
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• v.7 no.4
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• pp.127-136
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• 1994

For two-and three-dimensional problems, the vibration isolation effect of barriers in the travel path of waves has been studied using a boundary element method in the frequency domain. The soil is modelled as a half-space or a layered medium. The results indicate that the effectiveness of a wave barrier is strongly dependent on its location and depth with respect to the vibration source and that the optimum values of these two parameters are sensitive to vibration frequencies.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.24 no.62
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• pp.97-109
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• 2001

This research is concerned with jobshop scheduling problem for an advanced manufacturing system like flexible manufacturing which consists of two machine centers and a single automated guided vehicle(AGV). The objective is to develop and evaluate heuristic scheduling procedures that minimize makespan to be included travel time of AGV. A new heuristic algorithm is proposed and illustrates the proposed algorithm. The heuristic algorithm is implemented for various cases by SLAM II. The results show that the proposed algorithm provides better solutions in reduction ratio and frequency than the previous algorithm.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.3-8
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• 2006

This paper discusses current challenges, as a result of the rapid increase in air travel, and future navigation needs of Civil Aviation. The objectives pursued by ANASTASIA, a sixth framework European Commission project, are presented. The methods used in the derivation of the navigation performance requirements are introduced and discussed in the context of precision approaches. High-level impacts on the avionics receiver of integrating additional multi-frequency ranging signals from a modernized GPS and Galileo into the current navigation architecture are investigated. Expected performance achievements are presented.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3322-3324
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• 1999

This paper studies on the design and fabrication of a micro in-plane positioning actuator integrated with a microlens. Proposed in-plane actuator is a micro XY-stage which is composed of two linear comb drive actuators being orthogonal to each other. In the fabrication of actuator, the single crystalline silicon substrate anodically bonded with a #7740 glass substrate is used because of simple release and passivation. The structure of actuator is formed on the silicon facet of bonded fixture by chlorine-based deep RIE and then released by isotropic wet etching of glass (#7740) in hydrofluoric acid solution. Fabricated actuator has a large travel range up to $30({\pm}15){\mu}m$ and high resolution less than 0.01f1l1l in each direction. Experimented resonant frequency of this actuator is 630Hz. The micro-Fresnel lens is fabricated on the square-shape glass structure prepared in the center of actuator.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.107-109
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• 2015

본 연구는 내일로 티켓을 이용하는 관광객을 대상으로 하는 연구다. 여행을 떠나는 관광객들을 분석하여 이들의 특징과 강원도, 전라도, 경상도를 방문하는 패턴을 파악하여 각 지역의 주요 여행지와 특징을 순위 표와 워드클라우드를 활용하여 효과적으로 정보를 제공하는 것을 목표로 한다.