• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.8B
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• pp.1549-1557
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• 1999

In this paper, we propose a face recognition algorithm based on the differential image method-DCT This algorithm uses neural networks which is flexible for noise. Using the same condition (same luminous intensity and same distance from the fixed CCD camera to human face), we have captured two images. One doesn't contain human face. The other contains human face. Differential image method is used to separate the second image into face region and background region. After that, we have extracted square area from the face region, which is based on the edge distribution. This square region is used as the characteristics region of human face. It contains the eye bows, the eyes, the nose, and the mouth. After executing DCT for this square region, we have extracted the feature vectors. The feature vectors were normalized and used as the input vectors of the neural network. Simulation results show 100% recognition rate when face images were learned and 92.25% recognition rate when face images weren't learned for 30 persons.

• Resources Recycling
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• v.14 no.2
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• pp.3-9
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• 2005

A study on the air and gravity separation has been performed for the removal of chlorine containing materials from ASR of end-of-life vehicles. The gravity separation was also conducted on waste plastics collected from ASR. In this work, ASR were previously shredded to pass through 8 mm sieve prior to separation tests and the gravity separation of waste plastics was conducted for three different particle sizes. The two-stage air classification was conducted with the range of air flow rate of 9~20 M$^3$/hr at first stage and 25~34 M$^3$/hr at second stage, respectively. The fraction of overflow product was remarkably increased in the 2nd stage air classification because of high air flow rate while that of underflow product obtained from 1st stage air classification was found to be 62~66%. From the results of gravity separation on waste plastics, it was also found that the amount of the float product was much greater than sink product. It is believed that the gravity separation may be used very efficiently for the removal of calorine bearing materials from waste plastics.

• Clean Technology
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• v.26 no.3
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• pp.177-185
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• 2020

All coal ash, generated from coal-fired power plants, is entirely dumped onto a landfill site. As coal ash contains 80% fly ash, a clean floating process was developed in this study to recover useful components from coal ash and to use them as high value-added industrial materials. When the unburned carbon (UC) was recovered from the fly ash, soybean oil, an eco-friendly vegetable oil, was used as collector instead of a non-ionic kerosene collector to prevent the occurrence of odor from the kerosene. After the UC was separated by flotation, particulate ceramic microsphere (CM) was recovered, without generating acidic wastewater, through hydro-cyclone instead of sulfuric acid solution in order to separate ceramic microsphere (CM) and cleaned ash (CA) from the residue. By utilizing soybean oil as a collector, the recovery rate of UC turned high at 85.8% due to the increased adsorption of UC, the high viscosity of soybean oil, and the increase in floating properties caused by the linoleic acid contained in soybean oil. All of the combustible components contained in the recovered UC were carbon components, with the carbon content registering high when soybean oil was used. The recovered UC had many pores with a rough surface; thus, it could be easily ground and then used as an industrial material for its fine particles. The CM and CA recovered by the clean separation process using hydro-cyclone had a spherical shape, and the particles were clearly separated without clumping together. The average diameter (D₅₀) of the particles was 5 ㎛, so it was possible to realize the atomization of CM through a process change.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.5
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• pp.678-686
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• 1998

This paper describes an anisotropic perfectly matched layer (APML) for mesh truncation of the Finite Difference Time Domain(FDTD) method. The APML method can classified by a split type and an unsplit type, in case of the split type be made up 12 equations or 8 equations largely, and in case of the unsplit type be made of 6 equations. Therefore the latter is more simple as compare with the former. For the APML method presented in this paper is the latter, is directly derived from the time domain equations of Maxwell and extend to the three dimensional problem for the method suggested by Chen. Especially, in the edge and corner parts except the planes, the APML method effectively treated as compound with the Chen's method and Gedney's method newly. The results of the numerical method in this paper show the radiation patterns and the time responses of electromagnetic fields of the wire antennas according to wavelengths and the APML results are compared with Mur's first order absorbing boundary condition and Kraus's analytical results. Eventually, Mur's first order condition have many errors at the edge and corner. On the other hand, in comparison with Kraus's analytical results, it is quite good agreement, and the validity of present method is confirmed.

• Resources Recycling
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• v.30 no.5
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• pp.57-66
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• 2021

In this study, we attempted to separate and recover Cu from low-grade copper ore by a hydrometallurgical process. The leaching sample obtained after crushing and sieving by 0.355 mm of low-grade copper ore contained 1.5% Cu, 4.7% Fe, 1.0% Mn, and 0.3% Zn. The Cu in the oxide ore was very well leached into sulfuric acid and 97% Cu leaching efficiency was achieved at 80℃ and 3 M sulfuric acid (H₂SO₄). From the leaching solution, Cu was separated by solvent extraction from Fe, Mn, and Zn using LIX984N. The separation tendency between Cu and other metals was confirmed through the distribution ratio and separation factor. By plotting the McCabe-Thiele Diagram, the optimum condition for recovering Cu is 5 vol.% LIX984N, 2-stage counter-current solvent extraction, and an O/A ratio of 0.5. Using this method, 99% of the Cu was extracted and a CuSO₄ solution was finally obtained that contained 1.6 g/L Cu after the stripping process using 2 M H₂SO₄.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.206-206
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• 2016

플라즈마(plasma)란 전자와 이온이 분리된 제 4의 물질 상태이다. 이 연구의 핵심인 플라즈마 제트(plasma jet)로 재생과 출아를 하는 히드라(Hydra)를 처리하여 플라즈마가 히드라의 출아 정도에 어떠한 영향을 미치는지에 대해 연구를 진행하였다. 히드라는 자포동물문 히드로충강 히드로충목 히드라과 히드라속에 속하며 무척추동물이다. 몸의 길이는 약 5-15mm정도이며 촉수가 6-8개가 있다. 먹이 섭취는 촉수로 먹이를 마비시켜 입을 통해 먹는다. 히드라는 못이나 늪 등의 풀잎이나 물속에 떨어진 낙엽과 썩은 나뭇가지에 붙어 산다. 특히 히드라는 영양 상태의 좋고 나쁨에 따라 무성생식을 하거나 유성생식을 한다. 또한 약 1/200의 아주 작은 단위에서도 재생을 하는 특성을 가지고 있다. 이러한 히드라에 플라즈마 처리를 함으로써 플라즈마가 히드라의 출아 특성에 어떠한 영향을 미치는지에 대해 연구를 수행하였다. 실험에서 사용한 플라즈마 소스는 대기압 플라즈마 제트(Atmospheric pressure plasma jet)이며 Ar(아르곤) 가스를 이용하여 플라즈마를 발생시켰다. 플라즈마가 발생되면 생체용액과 반응을 하면서 ROS(reactive oxygen species)와 RNS(reactive nitrogen species)가 생성되는데 이 활성 종들이 플라즈마의 주요한 특성이라고 할 수 있다. ROS와 RNS에 의해서 세포가 사멸을 하거나 활성화되기도 한다. 또한, ROS와 RNS가 생체 시스템에 영향을 주는 것은 매우 잘 알려져 있다. 이 점을 이용하여 히드라를 1분, 5분, 10분 동안 플라즈마 처리하여 히드라의 출아 특성을 관찰하였다. 관찰한 결과 1분 처리한 히드라 Group과 5분 처리한 히드라 Group이 가장 개체 수 변화가 뛰어났고 10분 처리한 히드라Group은 오히려 개체 수가 감소하였다.

• 한국정보교육학회:학술대회논문집
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• 2007.08a
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• pp.346-351
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• 2007

교육인적자원부는 교육행정 전반의 효율성을 높이고 교원 업무 환경 개선을 위하여 교육행정정보시스템(NEIS)를 시행하고 있다. 그러나 교육행정정보시스템의 도입단계에서 시스템의 보안성 취약과 개인정보에 대한 해킹 우려 등의 이유로 교육행정정보시스템이 정착되지 못하였으나 NEIS의 27개 영역 중 개인정보를 많이 담고 있는 교무/학사, 입(진)학, 보건을 분리 별도의 서버를 구축하는 NEIS 교무업무시스템이 탄생하였다. 따라서 NEIS 교무업무시스템 활용하여 전자문서를 활용하여 이를 통한 교원업무가 경감되어 학교교육행정의 효율성을 모색할 필요성을 느끼게 되었다. 본 연구는 NEIS 교무업무시스템 활용에 따른 교원업무의 효율성을 분석하고자 하였다. 연구결과, 시스템 개선점 도출 및 편리성이 증진되었고 업무조직의 효율적인 분장 및 업무승인을 전자결재로 시행함으로써 시간단축 효과가 큰 것으로 나타났고 교원의 교무업무도 획기적으로 단축시켜 교원 업무의 효율성도 증진시켰다. 또한 교무업무시스템의 활용으로 소요시간과 예산이 절감되었다. 교무업무시스템의 이러한 교원 업무 경감 효과에 비추어 향후 과제를 제시하면 다음과 같다. 첫째, 교무업무시스템의 원활한 운영을 위하여 네트워크 정비나 성능 좋은 컴퓨터가 확보되어야 하고 둘째, 업무 효율화를 위해서 시스템 내에서의 업무 승인 기능이 확대되어야 하며 교원의 업무경감 및 시스템 운영의 활성화를 위해서 훈령을 학교현장의 여건에 맞추어 정비 보완해야 하며, 시스템 운영의 표준화를 위한 제도 개선이 필요하다.

• Proceedings of the Korea Contents Association Conference
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• 2015.05a
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• pp.223-224
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• 2015

구제역은 소, 돼지 등 발굽이 두 개로 갈라진 가축들에게 감염을 유발하는 전염성이 매우 높은 바이러스성 질병이다. 구제역 감염 시 입 주변, 구강 내, 코, 발굽사이 등에 수포가 생기며 고열과 식욕이 저하되어 심하게 앓거나 죽게 되는데, 강한 감염 전파력을 가졌음에도 치료제가 없고, 감염확인 즉시 확산 방지를 위한 살 처분만이 이루어지고 있다. 따라서 무엇보다도 빠른 감염여부 진단이 중요하다. 현재까지 구제역을 진단하는 방법으로는 감염 된 가축의 혈액에서 구제역 항원 단백질에 대한 항체형성 여부를 확인하는 항체진단법과 수포액과 같은 체액을 채취하여 세포배양을 통한 구제역 바이러스 분리방법이 있지만 두 가지 모두 짧은 잠복기를 갖는 구제역 바이러스를 빠른 시간 내 진단하기는 어렵다. 따라서 본 연구에서는 보다 빠른 구제역 진단 키트개발을 위해 NCBI Pubmed를 이용하여 구제역바이러스가 가지는 6개의 주요 단백질을 확인하였고, NCBI BLAST를 이용하여 6개의 단백질 중 구제역 바이러스에 특이적인 항원 단백질 peptidase C28을 선정하였다. 선정된 단백질의 아미노산 서열을 이용하여 IEDB analysis resource를 통해 peptidase C28의 epitope 부위를 예측하였다. 예측 된 부위의 아미노산 서열을 NCBI BLAST에서 정상 동물과 비교하여 구제역바이러스 특이 항원 단백질 epitope peptide를 최종 선정하였다. 이를 이용한 구제역 바이러스 진단키트 제작은 보다 빠른 진단을 통해 감염 확산을 조기에 차단하고 경제적 손실과 피해를 최소화 할 수 있다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.1
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• pp.118-124
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• 2001

In this paper, we proposed the novel digital watermarking for color still image using the characteristics of human visual system and the distribution of DCT coefficients. We insert watermark signal in the chromatic components of YCrCb color space according the characteristics of the human visual system that chromatic component are less sensitive than achromatic components. In order to extract the watermark signal, we use the relationship among the DCT coefficients of watermarked image without using original one. Simulation results show that the proposed watermarking method is better quality on invisibility than the conventional methods.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.6
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• pp.1046-1055
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• 1994

In this paper, to design high speed 1 line VRAM(Video RAM) suitable for image signal processing with ASIC(Application Specific IC) method, the VRAM memory core has been designed using 3-TR dual-port dynamic cell which has excellent access time and integration characteristics. High speed pipeline operation was attained by separating the first row from the subarray 1 memory core and the simultaneous I/Q operation for a selected single address was made possible by adopting data-latch scheme. Peripheral circuits were designed implementing address selector and 1/2V voltage generator. Integrated ASIC has been optimized using 1.5[ m] CMOS design rule.