• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.480-483
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• 1997

In this paper, we have proposed an automatic inspection system for cracks on the surface of a structure. The proposed system consists of the imaging system and the veh~cle system. The imaging system. a set of optical sensor, lens, illuminator, storage and their configuration, images the scene and store it on the hard disk. We adopted a linescan camera of 5000 pixel density to achieve high resolution without loss of simplicity. The vehicle system that moves the optical system IS ~mplemented by an AGV. The AGV moves forward at constant velocity and avoid obstacles to acquire a stable image. We have cmplemented an experimental system and have acquired images of the wall of hallway. The image is of 0.1-mmipixel resolution and the scanning time IS about 1 mlsec. The allow able scan.

• 전기화학회지
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• 제26권2호
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• pp.19-34
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• 2023

Due to the intermittency of renewable energy sources, a need to store and transport energy will increase. Hydrogen production through water electrolysis will provide an excellent way to supplement the intermittency of renewable energy sources. While alkaline water electrolysis is currently the most mature technology, it has drawbacks of low current density, large footprint, gas crossover, etc. The PEM water electrolysis has potential to replace the alkaline electrolysis. However, expensive catalyst material used in the PEM electrolysis has been the bottleneck of widespread use. In this review, we have reviewed recent efforts to reduce catalyst loading in PEM water electrolysis. In core-shell nanostructures, the precious metal catalyst forms a shell while heteroatoms form a core. In this way, the catalyst loading can be significantly reduced while maintaining the catalytic activity. In another approach, a corrosion-resistant support is utilized, which provides a stable platform to impregnate precious metal catalyst.

• 한국안전학회지
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• 제13권4호
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• pp.256-263
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• 1998

In this paper, we propose a volume holographic fingerprint recognition system based on optical correlator for personal identification. Optical correlator has high speed and parallel processing characteristics of optics. Matched filters are recorded into a volume hologram that can store data with high density, transfer them with high speed, and select a randomly chosen data element. The multiple reference images of database are prerecorded in a photorefractive crystal in the form of Fourier transform images, simply by passing the image displayed in a spatial light modulator through a Fourier transform lens. The angular multiplexing method for multiple holograms of database can be achieved by rotating the crystal by use of a step motor. Experimental results show that the proposed system can be used for the security verification system.

• JSTS:Journal of Semiconductor Technology and Science
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• 제7권4호
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• pp.229-234
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• 2007

In this paper, we present an efficient instruction set architecture using vector register file hardware to accelerate operation of general matrix-vector operations in DSP microprocessor. The technique enables in-situ row-access as well as column access to the register files. It can reduce the number of memory access significantly. The technique is especially useful for block-based video signal processing kernels such as FFT/IFFT, DCT/IDCT, and two-dimensional filtering. We have applied the new instruction set architecture to in-loop deblocking filter processing in H.264 decoder. Performance comparisons show that the required load/store operations for the in-loop deblocking filter can be reduced about 42%. The architecture would improve the processing speed, and code density in DSP microprocessor especially for video signal processing substantially.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.9-12
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• 2006

We performed molecular dynamics simulations on the conventional MOF, IRMOF-14 and the catenated MOF with two MOF chains, IRMOF13, to find out rational design and synthetic strategies toward efficient hydrogen storage materials. The molecular dynamics calculations were done using Universal force fields and the analysis of result was performed during the NVE dynamics after preliminary NVT dynamics at 77K. The results showed the density of adsorbed hydrogen molecules was increased in the various pores created by catenation of MOFs while the large amount of volume in conventional MOF was not effectively utilized to store hydrogen. Those calculation results commonly showed the proper control of pore si Be for hydrogen storage into MOF by catenation would be one of the efficient ways to increase hydrogen capacity of MOFs.

• 한국정밀공학회지
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• 제19권12호
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• pp.179-184
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• 2002

In this study, we developed a portable device which can monitor and analyze vibration signals from machines. This system consists a PDA loading the program for vibration analysis and A/D board for vibration acquisition. A PDA is smaller than the palm of the hand, but it has a powerful computing ability as much as an IBM compatible PC with a Pentium 100MHz CPU. The A/D board developed in this study supports LAN interface using TCP/IP communication protocol. The application program for vibration analysis includes signal processing module, fault diagnosis module, data store module, and plot display module. MS visual embedded C＋＋ 3.0 was used to developed the program.

• 한국지리정보학회지
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• 제10권2호
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• pp.164-171
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• 2007

본 연구는 GIS공간분석기법과 Huff의 확률모형을 이용하여 근린생활권중심의 상권분석을 수행하였다. 연구에 사용된 기본도는 청주시 복대동을 대상으로 하여 업종, 세대수 등을 현장 조사하여 구축하였으며, 기 구축된 LMIS에 있는 연속지적도를 활용하였다. 분석에서는 커널밀도함수(Kernel Density Function)와 최근린지수(Nearest Neighbor Index)를 활용하여 근린생활권내 점포분포 중심권역을 설정하였다. 상권분석을 수행하기 위하여 설정된 중심권역에 따라 중심지(점)와 규모를 산출한 후 상권분석의 모형인 Huff 확률모형에 적용하여 중심권역별 상권을 추출하였으며, 추출된 상권을 지도로 도식하였다. 따라서 본 연구에서는 GIS 공간분석기법 중 커널밀도함수와 최근린지수를 통해 Huff 확률모형에 적용할 수 있는 방법을 제시하였다. 이러한 방법들을 이용함으로써 보다 정확하게 상권분석을 할 수 있으며, 향후 창업하고자 하는 소상공인들에 도움이 될 수 있으리라 사료된다.

• 한국재료학회지
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• 제30권5호
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• pp.267-271
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• 2020

Cerium oxide (ceria, CeO₂) is one of the most wide-spread oxide supporting materials for the precious metal nanoparticle class of heterogeneous catalysts. Because ceria can store and release oxygen ions, it is an essential catalytic component for various oxidation reactions such as CO oxidation (2CO + O₂ 2CO₂). Moreover, reduced ceria is known to be reactive for water activation, which is a critical step for activation of water-gas shift reaction (CO + H₂O → H₂ + CO₂). Here, we apply van der Waals-corrected density functional theory (DFT) calculations combined with U correction to study the mechanism of water chemisorption on CeO₂(111) surfaces. A stoichiometric CeO₂(111) and a defected CeO₂(111) surface showed different water adsorption chemistry, suggesting that defected CeO₂ surfaces with oxygen vacancies are responsible for water binding and activation. An appropriate level of water-ceria chemisorption energy is deduced by vdW-corrected non-local correlation coupled with the optB86b exchange functional, whereas the conventional PBE functional describes weaker water-ceria interactions, which are insufficient to stabilize (chemisorb) water on the ceria surfaces.

• Nuclear Engineering and Technology
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• 제53권12호
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• pp.4137-4141
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• 2021

As NPPs continue to operate, liquid waste continues to be generated, and containers are needed to store and transport them at low cost and high capacity. To transport and store liquid phase very low-level radioactive waste (VLLW), a container is designed by considering related regulations. The design was constructed based on the existing container design, which easily transports and stores liquid waste. The radiation shielding calculation was performed according to the composition change of barium sulfate (BaSO₄) using the Monte Carlo N-Particle (MCNP) code. High-density polyethylene (HDPE) without mixing the additional BaSO₄, represented the maximum dose of 1.03 mSv/hr (<2 mSv/hr) and 0.048 mSv/hr (<0.1 mSv/hr) at the surface of the inner container and at 2 m away from the surface, respectively, for a 10 Bq/g of ⁶⁰Co source. It was confirmed that the dose from the inner container with the VLLW content satisfied the domestic dose standard both on the surface of the container and 2 m from the surface. Although it satisfies the dose standard without adding BaSO₄, a shielding material, the inner container was designed with BaSO₄ added to increase radiation safety.

• 한국지리정보학회지
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• 제20권2호
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• pp.89-101
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• 2017

본 연구는 소상공인의 상권 활성화를 위해 경상남도 창원시 도시지역을 대상으로 GIS 기법을 활용하여 전통시장과 대형할인점의 상권 특성을 분석하였다. 전통시장과 대형할인점의 정보를 GIS로 구축한 후, Kernel 밀도 분석, Network analysis, Huff 확률모형 등 다양한 GIS 공간분석기법을 적용하였다. 전통시장의 공간특성은 대형할인점이 밀집된 지역에 위치하는 것으로 나타났다. 상권특성을 도출한 결과, 대형할인점을 이용하는 소비자가 157,071명으로 전통시장 59,953명보다 약 3배 많았다. 이러한 현상의 원인은 인구가 밀집되고 전통시장에 인접한 지역에 대형할인점이 위치하고 있기 때문으로 판단된다. 따라서 소상공인의 상권 활성화를 위해서는 대형할인점 입지선정에 대한 기준 및 규제가 마련되어야 할 것이다. 본 연구는 도시지역의 상권 특성을 공간적이고 정량적으로 도출하였다. 향후 소상공인 상권 활성화를 위한 기초적인 자료로 활용될 것이다.