• Resources Recycling
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• v.22 no.3
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• pp.73-80
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• 2013

Metal prices are rapidly rising due to increasing demand of metals and limited available resources according to the industrial requirement. As a result, securing a stable supply of these metal resources has been recognized as a core element of national competitiveness and sustained economic growth. In the case of magnesium and its alloys which are entirely depending on import, low-grade magnesium scraps from end-of-life vehicles and 3C(Camera, Computer, Communication) parts and magnesium wastes such as sludge and dross generated during melting process are hardly recycled. Accordingly, the development and commercialization of recycling technology of low-grade magnesium scrap is desperately needed to improve efficiency of resource circulation and to establish the required proprietary of resource metal supply and demand. In this study, papers and patents on recycling technologies of waste magnesium were analyzed. The range of search was limited in the open patents of USA (US), European Union (EP), Japan (JP), Korea (KR) and SCI journals from 1974 to 2012. Patents and journals were collected using key-words searching and filtered by filtering criteria. The trends of the patents and journals was analyzed by the years, countries, companies, and technologies.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.11
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• pp.105-114
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• 2015

This paper proposes methods to remove background area and segment region of interest (ROI) in chest X-ray images. Conventional algorithms to improve detail or contrast of images normally utilize brightness and frequency information. If we apply such algorithms to the entire images, we cannot obtain reliable visual quality due to unnecessary information such as background area. So, we propose two effective algorithms to remove background and segment ROI from the input X-ray images. First, the background removal algorithm analyzes the histogram distribution of the input X-ray image. Next, the initial background is estimated by a proper thresholding on histogram domain, and it is removed. Finally, the body contour or background area is refined by using a popular guided filter. On the other hand, the ROI, i.e., lung segmentation algorithm first determines an initial bounding box using the lung's inherent location information. Next, the main intensity value of the lung is computed by vertical cumulative sum within the initial bounding box. Then, probable outliers are removed by using a specific labeling and the pre-determined background information. Finally, a bounding box including lung is obtained. Simulation results show that the proposed background removal and ROI segmentation algorithms outperform the previous works.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.3
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• pp.106-113
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• 1997

In uninterruptible power supply(UPS), a high speed phase control is usually required to compensate transients in the output voltage at the instant of transfer from the ac line to the inverter when the ac line fails or backs to the ac line in case of the inverter fails. To overcome this problem, this paper pre¬sents the closed digital phase-locked loop(DPLL) techniques designed by full software with TMS320C31 digital signal processor and describes the functional operation of the proposed DPLL. Fi¬nally, the performance of the proposed DPLL is shown and discussed through simulation and experiment.

• Journal of the Korean Society of Tobacco Science
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• v.21 no.2
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• pp.136-143
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• 1999

This study was conducted to evaluate the degradation characteristics of waste cigarette filters under 0, 5, 10, and 15cm in depth from soil surface by environmental conditions. Weather was the most important factor during degradation of waste cigarette filters in this study. Bulking of cellulose acetate filaments exposed on soil surface was observed after 2 months, but the form of filter was kept up after 12 months. The treated cigarette filters in soil landfill revealed a little different degradation pattern at each soil landfill depth, The sample in 5cm depth of soil was more degraded then other site. A fluffy appearance of cellulose acetate filaments in the control filter rods was also developed more strongly in soil landfill then on soil surface. From the observation of waste cigarette filters by scanning electron microscopy, much degradation of the fiber of waste cigarette filters could be ascertained in soil landfill. The weight of waste cigarette filters under 5cm from soil surface was reduced about 50%, and the tensile strength of the samples in soil surface and under 5cm from soil surface were reduced 66.0% and 92.4%, respectively. The microbial experiment date that the viable cell number in microbial population and cellulolytic microorganisms showed the maximum values under 5cm from soil surface, suggest that microorganisms in soil play an important roll in the degradation of acetate cigarette filters.

• The KIPS Transactions:PartB
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• v.10B no.5
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• pp.521-526
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• 2003

In this paper, we propose a geometric active contour model based on intensity information and curve evolution for detecting region boundaries. We put boundary extraction problem as the minimization of the difference between the average intensity of the region and the intensity of the expanding closed curves. We used level set theory to implement the curve evolution for optimal solution. It offered much more freedom in the initial curve position than a general active contour model. Our methods could detect regions whose boundaries are not necessarily defiened by gradient compared to general edge based methods and detect multiple boundaries at the same time. We could improve the result by using anisotropic diffusion filter in image preprocessing. The performance of our model was demonstrated on several data sets like CT and MRI medical images.

• Korean Journal of Materials Research
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• v.7 no.4
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• pp.347-353
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• 1997

BaTiO$_{3}$물질은 뛰어난 유전체로 널리 알려져 왔으며 특히 Heywang등이 제안한 PTCR특성은 이 물질의 응용범위를 세라믹 필터, 회로보호소자, 온도감지소자 및 저항가열장치 등으로 확대시켰다. 이러한 특성의 발현기구는 아직까지 밝혀지지 않은 상태이지만 제 특성을 향상시키기 위한 노력은 계속되어왔다. 특히 개발목적에 맞게 온도에 따른 정저항 특성(PTCR; Positive temperature constnat of resistivity phenomena)을 설계하려는 시도가 계속되어 왔으며 그 중에서도 페로브스카아트계의 2가와 4가의 양이온 자리를 등가나 원자가가 다른 양이온으로 치환하여 특성을 개선하려는 시도가 계속되어 왔다. 특히 $Ca^{2+}$나 Sr$^{2+}$는 $Ba^{2+}$자리를 치환할 수 있는 물질로 개별적인 첨가에 대한 연구는 많은 연구자들에 의해 진행된 상태이지만 최종적인 영향이나 해석에 대해서는 연구자들간에 이견이 많은 상태이다. 이번 실험에서는 BaTiO$_{3}$계에 합성한 (Ca, Sr)TiO$_{3}$를 Ca와 Sr의 상대적인 비를 변화시키면서 전체적인 첨가량을 변화시켜 그에 따른 전기적 특성 및 미세구조를 살펴보았다. (Ca, Sr)TiO$_{3}$의 첨가로 상온저항 및 PTCR특성을 변화시킬 수 있었으며 이를 통해 PTCR물질의 활용범위를 넓힐 수 있는 발판을 마련할 계기가 되었다. 특히 기존의 연구가 주로 개별적인 Ca나 Sr의 첨가에 의한 미세구조와 전기적 특성변화의 연구에 치중해 있었던 것과는 달리 Sr과 Ca을 함께 치환하여 상대적인 비가 특성에 더 중요한 영향을 끼치는 것을 확인하였으며 적절한 합성비를 선택하면 퀴리온도에서의 저항변화폭을 유지하면서 상온저항을 낮출 수 있음을 확인하였다.문했던 연구소인 Shanghai Research Center of Biotechnology, Shanghai Institute of Industrial Microbiology 및 Scientific Research Institute of Food and Fermentation Industry을 소개하고저 한다. 짧은 기간의 방문이라 주로 해당연구소의 자체소개 자료를 중심으로 방문하면서 느낀점을 기술하고저 한다.초염기성암 기원의 사문암이 열수변질작용을 받아 생성되었음을 명확하게 지시하며, 따라서 활석 광석내에 존재하는 녹니석은 활석의 근원 광물로서 녹니석편암 및 녹니석 편마암 매의 녹니석이 활석화되고 남은 잔존광물이 아니라, 주변암에 의해 성분상의 영향을 받은 열수와 사문암과의 변질교대작용에 의한 활석화과정 중에 주로 생성된 것으로 추정된다. 이러한 결과는 연구지역의 활석광상이 초염기성암의 사문암화 작용과 활석화 작용의 두 가지 변질작용에 의해 형성되어졌음을 알려준다.농도 증가 없이 폐 조직에 약 50배 정도의 고농도 cisplatin을 투여할 수 있었으며, 또한 분리 폐 관류 시 cisplatin에 의한 직접적 폐 독성은 발견되지 않았다이 낮았으나 통계학적 의의는 없었다[10.0%(4/40) : 8.2%(20/244), p>0.05]. 결론: 비디오흉강경술에서 재발을 낮추기 위해 수술시 폐야 전체를 관찰하여 존재하는 폐기포를 놓치지 않는 것이 중요하며, 폐기포를 확인하지 못한 경우와 이차성 자연기흉에 대해서는 흉막유착술에 더 세심한 주의가 필요하다는 것을 확인하였다. 비디오흉강경수술은 통증이 적고, 입원기간이 짧고, 사회로의 복귀가 빠르며, 고위험군에 적용할 수 있고, 무엇보다도 미용상의 이점이 크다는 면에서 자연기흉에 대해 유용한 치료방법임에는 틀림이 없으나 개흉술에 비해 재발율이 높고 비용이 비싸다는 문제가 제기되고 있는 만큼 더 세심한 주의와 장기 추적관찰이 필요하리라 사료된다.

• Progress in Medical Physics
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• v.22 no.1
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• pp.28-34
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• 2011

To perform the Adaptive Radiation Therapy (ART), a high degree of deformable registration accuracy is essential. The purpose of this study is to identify whether the change of MV CBCT intensity can improve registration accuracy using predefined modification level and filtering process. To obtain modification level, the cheese phantom images was acquired from both kilovoltage CT (kV CT), megavoltage cone-beam CT (MV CBCT). From the cheese phantom images, the modification level of MV CBCT was defined from the relationship between Hounsfield Units (HUs) of kV CT and MV CBCT images. 'Gaussian smoothing filter' was added to reduce the noise of the MV CBCT images. The intensity of MV CBCT image was changed to the intensity of the kV CT image to make the two images have the same intensity range as if they were obtained from the same modality. The demon deformable registration which was efficient and easy to perform the deformable registration was applied. The deformable lung phantom which was intentionally created in the laboratory to imitate the changes of the breathing period was acquired from kV CT and MV CBCT. And then the deformable lung phantom images were applied to the proposed method. As a result of deformable image registration, the similarity of the correlation coefficient was used for a quantitative evaluation of the result was increased by 6.07% in the cheese phantom, and 18% in the deformable lung phantom. For the additional evaluation of the registration of the deformable lung phantom, the centric coordinates of the mark which was inserted into the inner part of the phantom were measured to calculate the vector difference. The vector differences from the result were 2.23, 1.39 mm with/without modification of intensity of MV CBCT images, respectively. In summary, our method has quantitatively improved the accuracy of deformable registration and could be a useful solution to improve the image registration accuracy. A further study was also suggested in this paper.

• Progress in Medical Physics
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• v.19 no.3
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• pp.143-149
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• 2008

The aim of this study is to suggest the method for image enhancement of digital chest radiograph and evaluate clinically the quality of the resultant image. A nonlinear iterative filter was developed in order to reduce quantum noise preserving edge. Dynamic range was adjusted and adaptive image enhancement was performed based on the property of anatomic region and the degree of compatibility with neighboring pixels. The lung fields were enhanced appropriately to visualize effectively vascular tissue, bronchus and lung tissue with the desired mediastinum enhancement. Clinic evaluation was performed by three radiologists with at least 8 years experience. The anatomic regions of 11 in PA and 9 in Lateral were observed carefully in each 100 radiographs according to ITU (International Telecommunication Union) recommendation 500 protocol. The result showed the mean 3.4 between good and adequate. This means that the clinical utility of the image quality is enough. In this study, image enhancement was carried out considering image display device and human perceptual system to prevent the loss of useful anatomic information. In order to increase the diagnostic accuracy in digital radiograph, the continuous study on image enhancement is needed.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.2
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• pp.30-39
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• 2009

Extraction of glomeruli region plays a very important role for diagnosing nephritis automatically. However, it is not easy to extract glomeruli region correctly because the difference between glomeruli region and other region is not obvious, simultaneously unevennesses that is brought in the sampling process and in the imaging process. In this study, a new method for extracting renal glomeruli region using genetic algorithm is proposed. The first, low and high resolution images are obtained by using Laplacian-Gaussian filter with ${\sigma}=2.1$ and ${\sigma}=1.8$, then, binary images by setting the threshold value to zero are obtained. And then border edge is detected from low resolution images, the border of glomeruli is expressed by a closed B-splines' curve line. The parameters that decide the closed curve line with this low resolution image prevent the noises and the border lines from breaking off in the middle by searching using genetic algorithm. Next, in order to obtain more precise border edges of glomeruli, the number of node points is increased and corrected in order from eight to sixteen and thirty two from high resolution images. Finally, the validity of this proposed method is shown to be effective by applying to the real images.

• Clean Technology
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• v.13 no.2
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• pp.122-126
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• 2007

When ammonia ($NH_3$) gas was supplied to a biofilter packed with bio-carrier made of waste polyurthane and worm cast. No odor gases were detected at the outlet of the biofilter when $NH_3$ gas was supplied to the biofilter at the space velocity(SV) of $50\;h^{-1}$ until the inlet $NH_3$ concentration increased to $4\;{\sim}\;454\;ppmv$. The gradual inlet $NH_3$ concentration was set and the removal efficiency of $NH_3$ gas was measured at each condition, while the SV of $NH_3$ increased step by step from 100 to $400\;h^{-1}$. The maximum possible inlet $NH_3$ loading was $11.38\;g-NH_3{\cdot}m^{-3}{\cdot}h^{-1}$ and $34.42\;g-NH_3{\cdot}m^{-3}{\cdot}h^{-1}$ while maintaining the removal efficiency of 100% when the SV was $50\;h^{-1}$ and $100 \;h^{-1}$, respectively. The maximum $NH_3$ loading was $71.28 \;g-NH_3{\cdot}m^{-3}{\cdot}h^{-1}$ with the $NH_3$ removal efficiency of 99.85% at SV $300\;h^{-1}$.