• Proceedings of the KAIS Fall Conference
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• 2007.11a
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• pp.305-307
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• 2007

Struvite(MAP) 및 hydroxyapatite(HAP) 결정화로 질소 및 인을 제거하기 위한 최적조건을 평가하기 위한 실험을 실시하였으며, $Mg^{2+}$, $NH_4^+$, $PO_4^{3-}$ 및 $Ca^{2+}$용액을 이용하여 인공폐수를 조제하였으며 각 이온의 몰비 조건을 1:1:1에서 실험을 수행하였다. $Ca^{2+}$ 및 $PO_4^{3-}$를 이용한 HAP 결정화는 알칼리조건의 pH 범위에서는 pH에 큰영향을 받지 않고 HAP가 형성되었으며, MAP 및 HAP 동시 결정화를 위한 실험에서는 pH가 증가하면서 $NH_4^+$, $PO_4^{3-}$ 제거효율은 감소하며 $Ca^{2+}$ 및 $Mg^{2+}$는 모든 pH에서 99% 이상 제거되었다. 폐수중에 $Ca^{2+}$이 포함되어 있다면 pH 9.5에서 $Mg^{2+}:NH_4^+:PO_4^{3-}:Ca^{2+}$는 1.2:1.0:1.2:2.0의 몰비로 존재했을 때 MAP 및 HAP 생성 최적조건인 것으로 나타났다. 그러나 pH가 10이상이 되면 부반응으로 인해 각종 무정형 결정체가 생성되므로 MAP 생성을 위해서는 pH 9.5로 운영을 하는 것이 가장 바람직하다.

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.1
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• pp.33-39
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• 2022

Batch experiments were conducted to find out the effects of various types of magnesium compounds on phosphorus recovery by magnesium ammonium phosphate (MAP) crystallization. The phosphorus recovery from the centrate of anaerobic digested sludge was performed using magnesium chloride, magnesium hydroxide and magnesium oxide under different pH (7.5, 8.0 and 8.5) and Mg/P molar ratio (1.0, 1.5, 2.0, 2.5) conditions. The phosphorus recovery rate increased with increasing pH and Mg/P molar ratio in all magnesium compounds. At pH 7.5, magnesium oxide showed the highest phosphorus recovery rate, followed by magnesium hydroxide and magnesium chloride. However, at pH 8.5, more than 90% of phosphorus recovery rate was obtained in all Mg/p molar ratios. Thus, it is expected that magnesium hydroxide and magnesium oxide are able to replace magnesium chloride as a magnesium source in terms of phosphorus recovery efficiency and cost.

• Journal of Broadcast Engineering
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• v.15 no.2
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• pp.232-235
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• 2010

This paper proposes an efficient depth-map coding method. The adaptive block-based depth-map coding method decides the number of bit planes to be encoded according to the quantization parameters to obtain the desired bit rates. So, the depth-map coding using the block-based decision of the bit-plane to be encoded proposes to free from the constraint of the quantization parameters. Simulation results show that the proposed method, in comparison with the adaptive block-based depth-map coding method, improves the average BD-rate savings by 3.5% and the average BD-PSNR gains by 0.25dB.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.2066-2070
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• 2008

본 연구는 인공신경망(Artificial Neural Networks: ANNs)기법의 일종인 자기조직화(Self Organizing Map: SOM) 이론을 이용한다. 자기조직화 특성을 이용하여 스스로 학습이 가능하고, 구조상 수행이 빨라 학습 단계에 소요되는 시간을 줄 일 수 있는 장점을 가진 자기조직화 이론을 도입하고, 수질자료 중 전체 유기물의 양을 나타내며 난분해성 물질에 대한 해석이 가능하고 재현성이 탁월한 TOC 와 강우-유출량 자료의 분포적 양상과 특징을 분석하여 예측을 위한 모형화 과정에 기여하고자 한다. 최적의 Map Size와 Map Array 결정을 위해 수집된 강우와 유출량자료 및 TOC 자료에 대해 Garcia의 경험식을 이용하여 Map을 구성하는 단위구조의 총 수(M)를 산정하여 M값에 따른 종방향 및 횡방향 크기를 결정하는 다수의 Map 크기를 검토하고, 또한 Map 배열은 2차원 배열의 사각형배열(Rectangular array)과 육각형배열(Hexagonal array)에 대해서도 복합적으로 검토하여 최적의 특성조건을 결정하여 강우-유출 및 TOC 관계의 분할특성을 분석한다.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04b
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• pp.475-477
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• 2001

본 논문은 사용자의 구매 패턴을 찾아서 사용자가 원하는 상품을 추천하는 알고리즘을 제안하고자 한다. 제안하고 있는 item dependency map은 구매된 상품간의 관계를 수식화 하여 행렬의 형태로 표현한 것이다. Item dependency map의 값은 사용자가 A라는 상품을 구매한 후 B 상품을 살 확률이다. 이런 정보를 가지고 있는 item dependency map은 홉필드 네트웍(Hopfield network)에서 연상을 위한 패턴 값으로 적용된다. 홉필드 네트웍은 각 노드사이의 연결가중치에 기억하고자 하는 것들을 연상시킨 뒤 어떤 입력을 통해서 전체 네트워크가 어떤 평형상태에 도달하는 방식으로 작동되는 신경망 중의 하나이다. 홉필드 네트웍의 특징 중의 하나는 부분 정보로부터 전체 정보를 추출할 수 있는 것이다. 이러한 특징을 가지고 사용자들의 일반적인 구매패턴을 일부 정보만 가지고 예측할 수 있다. Item dependency map은 홉필드 네트웍에서 사용자들의 그룹별 패턴을 학습하는데 사용된다. 따라서 item dependency map이 얼마나 사용자 구매패턴에 대한 정보를 가지고 있는지에 따라 그 결과가 결정되는 것이다. 본 논문은 정확한 item dependency map을 계산해 내는 알고리즘을 주로 논의하겠다.

• Korean Journal of Materials Research
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• v.3 no.4
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• pp.336-343
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• 1993

The standard map for polyerystalline $YBa_2Cu_3O_7$-X was construeted and indexed from pressed tape sintered bulk and compressed bulk samples were drawn by the [001-110-110] stereographie quadrant map and by the ECPs from individual grains of the speeimens. The relationship between the (001) texture development and critical current density (Jc) for various samples was discussed. An (001) orintation was preferred in the pressed tape thickness was decreased. and in the compressed bulk as the compression strain was increaesed.The (001) orientation made a signifieant in crease on Jc. We conclded that an ECP technique was very useful for the analysis of the orientation distribution in small-sized $YBa_2Cu_3O_7$-X specimens such as superonducting tapes or thin films.

• Journal of the Korea Computer Graphics Society
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• v.3 no.1
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• pp.23-28
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• 1997

We reconstruct 3D surface from range image that consists of range map and texture map, and simplify the reconstructed triangular mesh. In this paper, we introduce fast simplification method that is able to glue texture to 3D surface model and adapt to real-time multipled level-of detail. We will verify the efficiency by applying to the scanned data of Korean relics.

• Journal of Korea Water Resources Association
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• v.41 no.10
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• pp.995-1007
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• 2008

Studies on modeling the rainfall-runoff relationship which shows nonlinear trend strongly use artificial neural networks theory not only for the prediction but also for the characteristics analysis of the data used by pattern classification. For the pattern classification, the results from Self-Organizing Map (SOM) mention that the map size and array for the SOM training have significantly influenced on the SOM performance. Since there is no deterministic method or theoretical equation to determine the number of rows and columns for the map size, hexagonal array is generally used for the map array. Therefore, this study present a determination of the optimized map structure for the rainfall-runoff analysis in Naju station considering the map size and array simultaneously which can represent the classified characterization of rainfall-runoff relationship. The result showed that the map size of 20$\times$16 hexagonal array with 8-clustered patterns was selected as an appropriate map structure for rainfall-runoff analysis in Naju station.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.19 no.4
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• pp.327-335
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• 2001

This paper present to how to make VGIS(Virtual Geographic Information System) using GIS and digital map. Because the development of the GIS has been 2-dimension in the last few years, viewpoint of the high-resolution image estimate was difficult. The geo-spatial information system has lots of errors in the policy decision and the principal decision making because it was displayed as 2 dimension map that the digital map and topographical map, geological map. agronomical map, cadastral map and underground facility map are expressed as a symbol practically in spite that it is spatial topography data. It is utilized as effective administration analyzing, all kinds of discussion, transportation and environmental effect evaluation, various kinds of building discussion and policy decision thorough researching the present condition of region as 3 dimension map using digital map and GIS when drafting and deciding all kinds of urban plaining so it is considered that errors of policy decision will be minimized.

• The Journal of the Korea Contents Association
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• v.11 no.6
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• pp.18-25
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• 2011

Salient object attracts more and more attention from researchers due to its important role in many fields of multimedia processing like tracking, segmentation, adaptive compression, and content-base image retrieval. Usually, a saliency map is binarized into black and white map, which is considered as the binary mask of the salient object in the image. Still, the threshold is heuristically chosen or parametrically controlled. This paper suggests using the global optimal threshold to perform saliency map thresholding. This work also considers the usage of multi-level optimal thresholds and the local adaptive thresholds in the experiments. These experimental results show that using global optimal threshold method is better than parametric controlled or local adaptive threshold method.