• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.482-482
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• 2012

대기압 플라즈마 소스는 미생물을 살균하는 효과를 가지고 있으나 그 메커니즘에 대해서는 여전히 많은 연구가 필요한 실정이다. 우리는 본 연구에서 메커니즘 규명을 위한 시작단계로 플라즈마에 대한 미생물의 반응을 생물학적 및 물리적 분석을 통해 보고자 하였다. 연구에 사용한 미생물은 yeast인 Saccharomyces cerevisiae 이며 Ar Gas 플라즈마를 사용하였다. Yeast에 일정한 시간 동안 플라즈마를 조사한 후 세포의 생존, 모양 변화 관찰 및 DNA에 대한 영향이 분석되었고 r-FIB 장비를 이용하여 세포표면의 이차전자 방출계수를 측정하였다. 플라즈마 조사 시간에 따라 Yeast active cell의 수가 감소하며, water에 넣고 조사할때에는 YPD media에 넣고 조사한 것에 비해 급격히 감소함을 볼 수 있다. 셀의 모양 관찰 결과도 water에 넣고 조사할 때, YPD media보다 더 찌그러듬을 볼 수 있다. 플라즈마 조사량에 따라서 Water의 PH 값은 YPD에 비해 급격히 낮아짐을 보인다. pH의 값을 달리하고 SNP와 H2O2가 첨가된 water에 Yeast를 배양시킬 때, pH의 값이 낮아질수록 yeast의 생존도 감소함을 볼 수 있다. 그리고 DNA gel electrophoresis를 통해 플라즈마 처리를 하게되면 Yeast의 DNA 양이 감소하는 것을 관찰할 수 있다. 또한 플라즈마 처리를 3분 하였을 때의 Yeast 세포막으로부터 방출되는 이차전자방출계수는 다른 처리시간에 대한 값에 비하여 확연히 증가하는 것을 볼 수 있다. 이들 사실로부터 플라즈마의 효과로 인해 외부의 전자를 흡수 및 차단할 수 있는 기능을 갖고 있는 Yeast 세포막의 구조가 변형되어 손상되었음을 의미한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.4C
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• pp.472-484
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• 2004

We proposed 3D mesh watermarking algorithm using CEGI distribution. In the proposed algorithm, we divide a 3D mesh of VRML data into 6 patches using distance measure and embed the same watermark bits into the normal vector direction of meshes that mapped into the cells of each patch that have the large magnitude of complex weight of CEGI. The watermark can be extracted based on the known center point of each patch and order information of cell. In an attacked model by affine transformation, we accomplish the realignment process before the extraction of the watermark. Experiment results exhibited the proposed algorithm is robust by extracting watermark bit for geometrical and topological deformed models.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.8B
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• pp.677-686
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• 2012

In the presence of a high power cellular network, picocells are added to a Macro-cell layout aiming to enhance total system throughput from cell-splitting. While because of the different transmission power between macrocell and picocell, and co-channel interference challenges between the existing macrocell and the new low power node-picocell, these problems result in no substantive improvement to total system effective throughput. Some works have investigated on these problems. Pico Cell Range Expansion (CRE) technique tries to employ some methods (such as adding a bias for Pico cell RSRP) to drive to offload some UEs to camp on picocells. In this work, we propose two solution schemes (including cell selection method, channel allocation and serving process) and combine new adaptive frequency partitioning reuse scheme to improve the total system throughput. In the simulation, we evaluate the performances of heterogeneous networks for downlink transmission in terms of channel utilization per cell (pico and macro), call blocking probability, outage probability and effective throughput. The simulation results show that the call blocking probability and outage probability are reduced remarkably and the throughput is increased effectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.1
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• pp.1-7
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• 1998

The near field radiated from the monopole antenna of the cellular phone was calculated by using the modified finite difference time domain algorithm derived from the integral form of Maxwell's equations. Substituting the near field value into the differential form of Maxwell's equations, SAR's distribution in the human head was obtained. The human head was simulated by a model of 800,000 block cells with dielectric constant and conductivity. The cell size was taken to be 0.5 cm. the transmitted power of the cellular phone was assumed to be 0.6 watts at the frequency of 833 MHz. The distance between the head and the cellular phone was 2.0 cm, the maximum SAR induced in the human head was about 1.5 W/kg and was below the IEEE's upper safety limit of 1.6 W/kg.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.1
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• pp.81-87
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• 2010

The coverage ability is one of essential techniques for the Robotic Vacuum Cleaner (RVC). Most of the RVCs rely on random or regular pattern movement to cover a target space due to the technical difficulties to implement localization and map and constraints of hardwares such as controller and sensors. In this paper, we consider two main issues which are low computational load and using sensors with very limited sensing capabilities. First, in our approach, computing procedures to build map and detect the RVC's position are minimized by simplifying data obtained from sensors. To reduce computational load, it needs simply presenting an environment with objects of various shapes. Another isuue mentioned above is regarded as one of the most important problems in our approach, because we consider that many RVCs use low-cost sensor systems such as an infrared sensor or ultrasonic sensor with limited capabilities in limited range, detection uncertainty, measurement noise, etc. Methods presented in this paper are able to apply to general RVCs equipped with these sensors. By both simulation and real experiment, we evaluate our method and verify that the proposed method guarantees a complete coverage.

• The KIPS Transactions:PartD
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• v.16D no.4
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• pp.487-496
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• 2009

This paper addresses an indexing scheme capable of efficiently processing range queries in a large-scale trajectory database. After discussing the drawbacks of previous indexing schemes, we propose a new scheme that divides the temporal dimension into multiple time intervals and then, by this interval, builds an index for the line segments. Additionally, a supplementary index is built for the line segments within each time interval. This scheme can make a dramatic improvement in the performance of insert and search operations using a main memory index, particularly for the time interval consisting of the segments taken by those objects which are currently moving or have just completed their movements, as contrast to the previous schemes that store the index totally on the disk. Each time interval index is built as follows: First, the extent of the spatial dimension is divided onto multiple spatial cells to which the line segments are assigned evenly. We use a 2D-tree to maintain information on those cells. Then, for each cell, an additional 3D $R^*$-tree is created on the spatio-temporal space (x, y, t). Such a multi-level indexing strategy can cure the shortcomings of the legacy schemes. Performance results obtained from intensive experiments show that our scheme enhances the performance of retrieve operations by 3$\sim$10 times, with much less storage space.

• Journal of Mushroom
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• v.10 no.2
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• pp.74-82
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• 2012

Sixty strains of Pleurotus ostreatus, white-rot fungi, were screened for production ability of their lignocellulolytic enzymes to selectively wood degradation. That results were shown that all of screened strains were produced lignocellulolytic enzymes on 2nd screening liquid culture medium. However, cellulase activity of selected six strains of P. ostreatus was low in avicel-yeast-peptone liquid culture medium. In the case of xylan degrading enzyme, No. 6 and No. 38 strains produced a xylanase(above 1.0U/ml) and a 1,4-${\beta}$-xylosidase (above 0.15 U/ml). Examination of the ligninolytic enzyme profiles of selected thirteen strains of the P. ostreatus, in the presence of Remazol Brilliant Blue R(RBBR), were observed that laccase(Lac) activity were earlier reached maximum level(0.8-2.0 U/ml) and then Mn-dependent peroxidase (MnP) were reached maximum level(0.5-1.5 U/ml) in glucose-yeast-peptone(GYP) medium. On the other hand, activity of lignin peroxidase(LiP) was not detected in this medium. I selected the No. 42 strain of P. ostreatus produced high levels of Mn-dependent peroxidase and laccase based on the screening method.

• Korean Chemical Engineering Research
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• v.45 no.3
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• pp.304-309
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• 2007

In this study, the "Multi Well Plate-type cell Apparatus" was designed and setup for performing the producing experiments of methane hydrate by depressurization, heat stimulating methods. In order to characterizing the producing mechanism of hydrate through porous materials, the experiments for various producing methods have been conducted with the aid of the apparatus which has high permeability. In the experimental result of depressurization method, the pressure is temporarily increased unlikely conventional gas reservoir due to the sourcing effect of hydrate dissociation in the pore. Meanwhile, the temperature is decreased because of the endothermic reaction while hydrate is dissociated. In the experimental results of heat stimulating method, the dissociation in depressurization method is more slowly processed than that in thermal method, and hence, its gas production is lower. In the case of production right after heating, hydrate is dissociated only near injecting point and the permeability becomes greater at that area only. It infers that the more gas is produced during relatively earlier producing period. Since then, the hydrate is more slowly dissociated than the case of production after heating and soaking. This time, the performances of pressure and production obtained by thermal method have been analyzed in order to investigate the effect of soaking time on gas recovery. As a result, the gas recoveries in the case of 2 min and 4 min soaking are higher than case in 6 min soaking. This is reason that hydrate is reformed due to the decrease of temperature. It is expected that the experimental results obtained in this work may be more clearly explained by utilizing the lower permeable porous system with the greater hydrate saturation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1775-1781
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• 2008

The effects of the type of curing agent on the swelling of the natural rubber(NR) sponge applicable to the self-sealing layer of a helicopter fuel tank were investigated. The curing systems employed were peroxide and mixed ones of sulfur and peroxide. The NR compounds were prepared in a kneader and a roll-mill. The compounds were partially cured in a press at high pressure and subsequently cured fully with expansion in another press at atmospheric pressure. The apparent density of the NR sponge was measured and the cell structure was observed with scanning electron microscopy. The swelling experiments were performed at room temperature using toluene, iso-octane, and an aircraft fuel as a solvent. More rapid volume swelling of the NR sponge cured by peroxide was achieved than cured by sulfur and peroxide with similar amount of curing agent added in rubber compounds. The apparent density and cell structure of the sponge were extremely sensitive to the amount of peroxide, which influences again the swelling behavior of the NR sponge. It is important to control properly two reactions of decomposition of foaming agent and crosslinking of NR in the mold to obtain rapid swelling of the NR sponge on contact of the fuel.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.24-24
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• 2020

본 연구는 자생 털부처꽃의 실용적인 산업화를 위해 지피용 재배조건을 조사하고자 수행되었다. 실험재료는 털부처꽃의 종자를 2019년 4월말에 파종하여 8주 후 얻어진 유묘를 사용하였다. 실험은 식재용기(2, 3, 4치 비닐포트), 토양종류(원예상토 단용 및 마사토:피트모스 혼용토(v/v; 2:1, 3:1), 파종용기(162, 200, 288셀 플러그트레이) 및 파종립수(1, 2, 4립)를 달리하였으며, 정식 후 처리구간의 생육특성을 조사하였다. 또한 마사토와 피트모스 혼용토는 9L당 퇴비 1L를 혼합하여 원예상토와 비교하였다. 대조구는 원예상토가 충진된 3치 비닐포트에 정식된 유묘와 셀당 1립이 파종된 200셀 플러그트레이의 유묘를 사용하였다. 유묘는 처리별로 정식한 다음 충북대학교 유리온실에서 12주간 재배되었으며, 매일 2회(5분/1회) 미스트 관수되었다. 연구결과, 털부처꽃의 유묘가 정식된 비닐포트는 포트의 볼륨이 클수록 생육이 우수한 경향을 나타냈다. 특히 4치 비닐포트는 동일한 재배기간 동안 경직경(3.61 mm), 측지수(28.2 ea), 엽수 (311.6 ea), 근장 (22.1 cm) 및 생체중(7049.9 mg)이 가장 많이 증가하였다. 토양종류는 원예상토를 단독으로 사용한 처리구의 생육이 가장 우수하였다. 반면 마사토와 피트모스 혼용토는 재배가 지속되면서 생육이 저조하여, 농업용 퇴비로는 양분이 부족한 것으로 보인다. 파종립수가 증가할수록 각 개체의 생육은 감소하였으나, 4립 파종구의 유묘는 정식 후 풍성한 볼륨을 나타냈으며, 지피용 재배목적에 부합하였다. 플러그트레이는 볼륨이 작아질수록 초장과 생체중이 일부 감소하는 경향을 나타냈으나, 전반적으로 생육은 유사한 경향을 나타냈다.