• The KIPS Transactions:PartB
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• v.17B no.6
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• pp.421-428
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• 2010

It takes a long time for the users to view a whole image from the image server under the low-bandwidth internet environments or in case of a big sized image. In this case, as there needs a technique that preferentially transfers a part of image, JPEG2000 offers a ROI(Region-of-Interest) coding. In ROI coding, the users see the thumbnail of image from the server and specifies some regions that they want to see first. And then if an information about the regions are informed to the server, the server preferentially transfers the regions of the image. The existing methods requested a huge time to compute the mask information, but this thesis approximately computes the regions and reduces the creating time of the ROI masks. If each code block is a mixed block which ROI and background are mixed, the proper boundary points should be acquired. Searching the edges of the block, getting the two points on the edge, to get the boundary point inside the code block, the method searches a mid point between the two edge points. The proposed method doesn't have a big difference compared to the existing methods in quality, but the processing time is more speedy than the ones.

• Progress in Medical Physics
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• v.6 no.2
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• pp.41-50
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• 1995

The absorbed dose and contaminant electron distribution of therapeutic X-ray beam (15MV photon) was studied with a half blocked beams of 30$\times$30$\textrm{cm}^2$ and field size ranging from 5$\times$5 to 30$\times$30$\textrm{cm}^2$. For a 15MV photon beam energy, the value of the depth of dose maximum, d$_{max}$, gradually decrease with increasing field size from 5$\times$5 to 30$\times$30$\textrm{cm}^2$ due to mainly by contaminant electrons which are produced in the flattening filter and scattered by collimator jaws, tray holder〔Lucite〕, blocking block and air. The results suggest that separate dosimetry data should be kept for blocked and unblocked field. The inherence of the contaminant electrons to the open field depth of maximum dose can lead to mistaken results if attenuation measurements are made at that depth. A nurmerous contaminant electrons mainly were distributed as shape of corn in the central photon beam and their path length in the water were shorter than 30mm because of the electrons energy having around 6MeV. These results clearly appears that the substraction of scattered electrons (electrons and positrons) from the total depth dose curve not only lowers the absolute dose in the bulidup region and surface dose, it also causes a shift of d$_{max}$ to a deeper depth. In the terapeutic high energy photon beam, the absorbed dose near the buildup region is the combined result of incident contaminant electrons and phantom generated electronsrons.

• Journal of Life Science
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• v.14 no.6 s.67
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• pp.963-966
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• 2004

The sequence of ITS (partial 16S ribosomal DNA, complete ITS1, 5.8S ribosomal DNA and ITS2, and partial 28S ribosomal DNA) was analysed by PCR and autosequencing in Sarcodon aspratus. The ITS lenght of S. aspratus was 716 base pair. As this sequence compared with other reports on S. aspratus (ace No AF335110), the sequence variation based on nucleotide deletion and substitution was $1.8\%$. This nucleotide variation rate in same species was very higher than in other species. Also, the sequence varitation rates between this S. aspratus and S. imbricatus, and S. squamus were $8\%\;and\;10\%$, respectively. This results suggested that the high sequence variation of S. aspratus might be caused specific host and inhabitat environment which limited gene flow.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.11 no.3
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• pp.135-140
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• 1999

To simulate the wave transformation by an energy dissipation region, a numerical model is suggested by discretizing the elliptic mild-slope equation. Generalized conjugate gradient method is used as solution algorithm to apply parabolic approximation to open boundary condition. To demonstrate the applicabil-ity of the numerical procedure suggested, the wave scattering by a circular damping region is examined. The feature of reflection in front of the damping region is captured clearly by the numerical solution. The effect of the size of dissipation coefficient is examined for a rectangular damping region. The recovery of wave height by diffraction occurs very slowly with distance behind the damping region.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.410-410
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• 2012

투명 전도성 TCO (Transparent Conductivity Oxide)박막 중 ITO (Indium Tin Oxide) 박막은 n-type의 전도특성을 갖는 산화물로서 가시광선 영역에서의 높은 투과율, 전기 전도도, 넓은 밴드갭을 나타내기 때문에 디스플레이 및 태양전지 분야에 널리 사용 되어 지고 있다. 이 실험에서는 ITO 증착시 산소 유량의 변화에 따라 특성의 변화를 관찰하고자 실험을 진행 하였다. 실험에서 산소 유량은 0 sccm에서 12 sccm까지 변화를 주었으며, ITO는 RF 마그네트론 스퍼터를 이용하여 유리위에 증착하였다. 실험에서 인가된 RF power는 2 kW, 13.56 MHz, 공정 압력은 $4.5{\times}10^{-6}torr$에서 진행하였다. 유리와 타겟 사이의 거리는 200 mm로 고정하였으며, 온도는 상온에서 공정을 진행하였다. 증착된 ITO의 전기전도도(${\sigma}$)는 3 sccm까지는 증가하는 경향을 보이다가 그 이후부터는 감소하는 것을 확인 할 수 있었다. 투과율과 이차전자방출계수의 결과 또한 전기전도도와 유사한 경향성을 보여 주었다. 이를 통해 3 sccm의 산소 유량으로 증착된 ITO의 전기적 특성이 가장 좋은 것으로 확인이 되었다.

• Journal of Korean Society for Geospatial Information Science
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• v.8 no.1 s.15
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• pp.73-84
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• 2000

Map matching technique is an essential part of the car navigation and other related positioning fields such as dead reckoning and GPS data logging upon the GIS database. This paper is to break down map matching techniques, to categorize them, and to propose a simple technique for GPS based map matching technique. For categorization of techniques, two approaches have been adopted. One is to only use geometric information, and the other is to use both geometric and topological information. Some pros and cons of each method have been described. In addition, a simple map matching technique, set forth in this paper, has been introduced for properly utilizing the advantage of GPS points after the absence of the chronic problem of selective availability, which had been prevailed recently. Some research opportunities and problems of the technique have also been discussed.

• Electrical & Electronic Materials
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• v.4 no.4
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• pp.330-337
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• 1991

y의 크기가 0.02에서부터 2.0까지의 두 차수만큼 변하게 불소가 첨가된 YBa$_{2}$Cu$_{3}$$O_{7-x}$F$_{y}$ 초전도물질을 금속질산염과 수산화나트륨 및 불화나트륨을 써서 졸-겔법으로 제조하였다. 불소함유양들을 이온-선택 전극을 사용하여 측정하였다. 반응물질로 첨가된 불소전부가 최종시료속에 존재한다는 것을 알았다. XRD 관측으로부터 y.leq.0.2인 시료들은 단지 단상 페로브스카이트 구조로 되었고 반면 y.geq.0.5인 것들은 최종시료속에 BaF$_{2}$ YF$_{3}$및 CuO와 같은 화합물들과 함께 생성되어져 있다고 결론지을 수가 있다. 더구나 고체 $^{19}$ F 핵자기공명관측이 불소가 정말로 격자위치들 속에 혼입되어 있는지 여부를 확인하기 위하여 행해졌는데 실험결과로부터 YBa$_{2}$Cu$_{3}$$O_{7-x}$ 격자위치속에 혼입된 불소의 몰비는 화합물 1몰당 약 0.2라는 것을 보여주었다. 또한 전기저항률의 측정은 개시감계온도가 y.leq.0.2와 같이, 지정된 첨가율이 적은 영역에서는 y의 증가에 따라 약간씩 증가하는 경향이 있음을 보여주고 있다.

• Journal of the Korean Society for Library and Information Science
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• v.47 no.1
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• pp.125-147
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• 2013

This study analyzed the effect of the cognitive style of field dependence/independence to the information-seeking behaviors of 250 undergraduate students. The cognitive style of field dependence/ independence was examined by Group Embedded Figure Test (GEFT), information-seeking behaviors were examined by information-seeking performances, and survey for information-seeking behaviors. As a result of the analysis, the cognitive style of field dependence/independence affected items of information-seeking performances except one item among items set in this study. The cognitive style, the cognitive characteristics acting in the process of cognitive activity affected the actual activities of information-seeking behaviors. The cognitive style of field dependence/independence affected the seeking process except the results of seeking and general information-seeking behaviors in the areas of information-seeking behaviors. Therefore, the study of cognitive style can be effective in the seeking process areas of information-seeking behaviors.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.569-569
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• 2013

대부분의 태양전지 공정은 퍼니스와 레이저 도핑 공정이 중요한 공정 중 하나다. 퍼니스 도핑공정의 경우 저농도 도핑영역에 선택적으로 고농도 도핑영역을 형성하기가 일반적으로 어렵다. 레이저를 사용한 선택적 도핑의 경우 고가의 레이저 장비가 요구되어지며, 레이저 도핑 후 고온의 에너지로 인한 웨이퍼의 구조적 손상 문제를 야기한다. 본 연구는 저가이면서 새로운 구조의 대기압 플라즈마 제트를 개발하였고, 이를 통한 선택적 도핑에 관한 연구를 하였다. 대기압 플라즈마 제트는 Ar 가스를 주입하여 저주파(1~100 kHz) 전원을 인가하여 플라즈마를 발생시키는 구조로 제작하였다. 웨이퍼는 P-type shallow 도핑 된(120 Ohm/square) PSG (Phosphorus Silicate Glass)가 제거되지 않은 웨이퍼를 사용하였다. 대기압 플라즈마 도핑 공정 처리시간은 15 s, 30 s, 플라즈마 발생 전류는 40 mA, 70 mA로 처리하였다. 웨이퍼의 도핑프로파일은 SIMS (Secondary Ion Mass Spectroscopy)측정을 하여 분석을 진행하였으며, 도핑 후 도핑프로파일을 통하여 면저항등 전기적 특성을 파악하였다. 도펀트인 PSG (Phosphorus Silicate Glass)에 대기압 플라즈마 제트로 도핑공정을 처리한 결과 전류가 상승함에 따라, 도핑 처리시간이 길어짐에 따라서 도핑깊이가 깊어지고, 면저항이 낮아짐을 확인하였다. 대기압 플라즈마 도핑 후 웨이퍼의 구조적 손상파악을 위한 SEM (Secondary Emission Microscopy) 측정결과 도핑 전과 후 웨이퍼의 표면구조는 차이가 없음을 확인하였다.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.40-44
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• 2009

Data-centric storage schemes(DCS) are one of representative researches that efficiently store and manage sensor readings in sensor nodes in the sensor networks. In DCS, a sensor sends the sensed data to a specific node in order to store them. However, it has a problem that sensor nodes consume a lot of energy for transmitting their readings to remote sensor node. In this paper, we propose a novel sensor data compression algorithm to reduce communication costs. The proposed algorithm does not transmit all the sensed data and establishes a safe region. It transmits the sensed data only when current measurement is out of the safe region, As a result, the propposed algorithm extends network life time and reduces data transmission. It is shown through performance evaluation that our proposed algorithm reduces energy consumption by about 60% over the conventional algorithm.