• 한국정보통신학회논문지
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• 제24권8호
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• pp.1071-1076
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• 2020

망 분리(Network separation)의 중요성은 기존 업무용 PC에 인터넷을 같이 사용함으로 내부 정보가 유출된 사건 등이 발생되고 서버들도 인터넷에 접근 가능 하도록 환경이 구성되어 악성코드로 서비스 장애가 발생되기 때문이다. 이러한 문제점을 극복하기 위해 네트워크 가상화를 이용한 망 분리와 망 연계 시스템과 병행이 필요하다. 따라서 본 연구에서는 인터넷용 네트워크 영역과 가상화 시스템 서버팜 영역으로 구성영역 구축하고 이후 보안 시스템 영역과 망간 자료 연계 시스템 영역으로 분류하여 구축 연구 하였다. 제안한 방법의 우수성을 입증하기 위해 국내 1만 user 이상의 사이트 조사를 통한 프로그램 부하와 LOB(Line Of Business)등이 VM(virtual machine) Density가 보수적 산정된 근거를 바탕으로 네트워크 가상화를 이용한 망 분리 구축이 연구 되었다.

• 한국가축번식학회지
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• 제12권3호
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• pp.141-147
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• 1988

These experiments were carried out to develop new techniques for in vitro separation of x-and Y-bearing spermatozoa. The results obtained in these experiments were summarized as follows: 1. Following centrifugation of discontinuous percoll density gradient, populatin of spermatozoa increased progressively from low to high density. The highest concentration of spermatozoa was observed at the 4th fraction which included 36.6% of spermatozoa. 2. As increasing percoll concentration, the higher motility index was obtained and the highest motility index(74.2) was obtained at the 5th fraction. 3. The percentage of B-body bearing spermatozoa following percoll density gradient centrifugation was decreased from 39.7% to 25.6%. 4. The sperm population following chromatography by sephadex gel and percoll density gradient centrifugation was decreased in 1st, 5th and 6th fractions but the reverse was turn for 2nd, 3rd and 7th fractions, and the highest sperm concentration was observed at the 7th fraction which included 37.4% of spermatozoa. 5. Motility index of spermatozoa was increased from 77.6 to 79.4 after the sephadex gel filtration, however it was decreased at all fractions after percoll density gradient centrifugation. The lowest motility index(33.2) was obtained from the 7th fraction. 6. The rate of B-body bearing spermatozoa was shown the trend to decrease by the sephadex gel filtration and the trend was accelerated by the percoll density gradient centrifugation. The lowest percentage of B-body bearing spermatozoa, 12.0% was obtained from the 5th fraction.

• 한국막학회:학술대회논문집
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• 한국막학회 1994년도 추계 총회 및 학술발표회
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• pp.32-33
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• 1994

Poly(vinyl alcohol)(PVA) membranes crosslinked with Glutaraldehyde (GA) were prepared for the separation of acetic acid-water mixtures. For the preparation of the crosslinked membranes, dry PVA films were immersed for 2 days at 40$\circ$C in reaction solutions which contain different content of GA solution(25% GA in water), aceton and a catalyst, HCl. IR spectroscopy was employed to characterize the crosslinking reaction between hydroxyl groups in PVA and aldehyde groups in GA. Swelling measurements of the crosslinked membranes were carried out in both water and acetic acid to investigate the crosslinking density and swelling behaviour of the membranes.

• 전기학회논문지
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• 제57권8호
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• pp.1454-1463
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• 2008

Blind source separation by independent component analysis (ICA) has applied in signal processing, telecommunication, and image processing to recover unknown original source signals from mutually independent observation signals. Neural networks are learned to estimate the original signals by unsupervised learning algorithm. Because the outputs of the neural networks which yield original source signals are mutually independent, then mutual information is zero. This is equivalent to minimizing the Kullback-Leibler convergence between probability density function and the corresponding factorial distribution of the output in neural networks. In this paper, we present a learning algorithm using information theory and higher order statistics to solve problem of blind source separation. For computer simulation two deterministic signals and a Gaussian noise are used as original source signals. We also test the proposed algorithm by applying it to several discrete images.

• 한국초전도ㆍ저온공학회논문지
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• 제24권3호
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• pp.7-11
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• 2022

We are conducting research and development of magnetic filters for magnetic separation targeting paramagnetic materials. In order to develop a new magnetic filter with a large magnetic gradient, stainless fiber (SUS430, 120 mm × 3 mm) with a triangular cross section was sintered with a high void ratio (~ 70%) and the magnetic filter (20 mm × 2 mm) was created. When this magnetic filter was used to perform magnetic separation of hematite (particle size 50 ㎛) under a maximum magnetic flux density of 1.49 T, high separation rates were obtained.

• 한국항행학회논문지
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• 제27권6호
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• pp.710-715
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• 2023

도시화가 가속화되면서 교통 혼잡, 주거 및 환경 문제 등의 사회적 이슈가 도출되고 있다. 이를 해결하기 위해 도심항공교통 (UAM; urban air mobility)과 같은 혁신적인 교통시스템 개발에 관한 연구가 활발하게 진행되고 있다. 초기 저밀도 운항 환경에서 기존의 항공교통시스템에 부담을 주지 않으면서도 안전하게 비행이 이루어져야 하고, 공역을 효율적으로 관리하고 운영하는 능력이 요구된다. 따라서 UAM은 회랑을 통한 경로의 운영으로 예측 가능성을 높여 초기 운영단계에서는 저밀도 상황에서의 운항에 대한 데이터를 축적해 나가는 것이 중요하다. 이를 위해서는 운영하기 전 각종 시뮬레이션을 활용한 시나리오를 생성하여 UAM 기체 간의 잠재적인 충돌 가능성을 예측하고 항공기 간격 즉 분리에 대한 손실 (LoS; loss of separation), 그리고 근접 공중충돌 (NMAC; near mid air collision) 위험에 대한 검토가 필요하다. 항적 난기류는 항공기 간의 안전한 분리를 보장하는 중요한 요소로, 기존 항공교통에서는 활주로와 항로의 분리에 필수적으로 사용되었다. UAM 비행체는 저고도에서 밀집된 공간에서 운영되기 때문에, 항적 난기류에 관한 추가적인 연구가 필요하며, 이를 위해 다양한 데이터를 활용하여 기체의 성능을 정밀하게 분석하고 있다. 본 논문에서는 국내외 연구 결과를 바탕으로 UAM의 분리 기준 설정에 필요한 요구사항과 고려해야 할 사항들을 확인하는 데 초점을 맞추고자 한다.

• 한국환경과학회지
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• 제17권11호
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• pp.1235-1241
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• 2008

Membrane separation is extensively used for water/wastewater treatment because of its efficiency separation processes. However, particles in the feed water can deposit and accumulate on the membrane surface to created cake layer. As a consequence, the selectivity of the membrane and flux through the membrane are decreased, which is called fouling/blocking phenomenon. In order to solve fouling problem, we developed a novel membrane named Carbon Whisker Membrane (CWM) which contains vapor-grown carbon fibers/whiskers on the surface of the membrane and a layer of carbon film coated on the ceramic substrate. We firstly employed polymethyl methacrylate (PMMA) as a testing material to investigate the fouling mechanism. The results suggested that Carbon Whiskers on the surface of the membrane can prevent the directly contact between the membrane body and particles so that the fouling/blocking could not occurred easily compared to the membrane without carbon whiskers. We also researched the relationship with the diameter, density of carbon whisker on the membrane surface and total flux of solutions. Finally, we will be able to control the diameter and density of carbon whiskers on the membrane and existence of carbon whiskers on the membrane, it is important factor, might be prevent fouling/blocking in the water treatment.

• 한국재료학회지
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• 제9권4호
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• pp.341-344
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• 1999

We reported compositional separation(CS) into Co-enriched and Cri-enriched components inside the grains of Co-Cr based thin films prepared by rf sputtering. CS strongly depends on the sputtering conditions of substrate temperature and target composition. Tuning the microstructure of the Co-Cr films is important in order to employ the CS for high-density magnetic recording. We investigated the origin of CS from thermodynamic viewpoint. We employ a spinodal decomposition-like model to describe the origin of the CS in Co-Cr films. We consider the total free energy of the Co-Cr films as the sum of several free energies of; 1) thermodynamic mixing entropy of a binary solid solution, 2) magnetic ordering interaction(MOI) energy below the Curie temperature, and 3) excess interaction energy(XS) caused by the sputtering process as a function of temperature and composition. Those energies distorted the total free energy like the spinodal decomposition and caused the compositionally separated fine microstructure inside the grains. If the second derivative of the total free energy with respect to Cr composition becomes negative at a given substrate temperature, we may observe a metastable compositional separation inside the Co-Cr alloy films. We expect to exploit the microstructure of CS for ultra-high density magnetic recording.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2006년도 춘계학술논문 발표대회 제6권1호
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• pp.111-114
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• 2006

Recently, it is increased on the concern for the reuse of waste concrete because of the shortage of natural aggregate and the increase of waste concrete. And recycled coarse aggregate is used variously, but the existing wet method producted recycled fine aggregate has problem like the high price facilities, the long time progress of the work and the poor of recycled fine aggregate. The aim of this study is to investigate outline and performance evaluation of the drying specific gravity separation method to product high duality recycled fine aggregate. Finally, this study is shown investigate process flowing of drying separation type with gravity manufacture, producte system and function of detail devices. The performance of the method of drying specific gravity separation is certificated as the qualities of recycled fine aggregate satisfied the KS

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.131-136
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• 2008

The oil separation in an oil separator is one of the most important characteristics for proper compressor operation. In this study, a gravity type of oil separator is used. Oil separation characteristics has been investigated for $CO_2$/PAG mixture in the range of oil concentration 0 to 5 weight-percent and the mixture temperature range of $5^{\circ}C$ to $15^{\circ}C$ and $70^{\circ}C$ to $90^{\circ}C$. The results obtained indicate that the oil separation is increased with an increase in the oil concentration. It is also found that the oil separation in liquid state is increased with an increase in the mixture temperature while the oil separation in gas state is decreased.