• 대한원격탐사학회지
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• 제25권2호
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• pp.145-154
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• 2009

고해상도 위성영상이 갖는 공간 객체의 복잡성과 다양성에 의해 기존 중 저해상도 영상에서 사용하던 분류 방식을 고해상도 영상에 그대로 적용하기에는 한계가 있다. 이러한 문제를 극복하기 위하여 영상의 공간적인 특성을 추가적으로 추출하여 분광정보와 결합하여 분류를 수행하는 방식의 연구가 진행되고 있다. 본 연구의 목적은 고해상도 영상의 분류정확도를 개선하기 위하여 새로운 공간 개체(spatial feature)인 SSI(Shape-Size Index)를 제안하는데 있다. SSI feature는 영역 확장(Region Growing) 기반의 영상 분할(Image Segmentation)을 수행한 후, 세그먼트 내에 공간 속성값을 할당하여 공간정보를 추출한다. 추출된 공간정보를 고해상도 영상의 다중분광 밴드와 결합하여 Support Vector Machine(SVM)을 이용한 분류를 수행하였다. SSI를 구성하는데 필요한 두 매개변수인 분할변수와 가중치변수의 최적값을 얻기 위해서 고해상도 위성영상인 KOMFSAT-2와 QuickBird-2에 반복적으로 적용하였다. 결과적으로 고해상도 영상의 공간특성을 표현하는데 적합한 매개변수를 통하여 도출된 SSI와 고해상도 분광 밴드를 결합하여 분류를 수행한 결과가 분광밴드만을 이용하여 분류를 수행한 결과에 비해 높은 분류정확도를 도출함을 확인하였다.

• 대한원격탐사학회지
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• 제31권4호
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• pp.337-346
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• 2015

Water body extraction based on backscatter information is an essential process to analyze floodaffected areas from Synthetic Aperture Radar (SAR) image. Water body in SAR image tends to have low backscatter values due to homogeneous surface of water, while non-water body has higher backscatter values than water body. Non-water body, however, may also have low backscatter values in high resolution SAR image such as Kompsat-5 image, depending on surface characteristic of the ground. The objective of this paper is to present a method to increase backscatter contrast between water body and non-water body and also to remove efficiently misclassified pixels beyond true water body area. We create an entropy image using a Gray Level Co-occurrence Matrix (GLCM) and classify the entropy image into water body and non-water body pixels by thresholding of the entropy image. In order to reduce the effect of threshold value, we also propose Water Body Texture Index (WBTI), which measures simultaneously the occurrence of repeated water body pixel pair and the uniformity of water body in the binary entropy image. The proposed method produced high overall accuracy of 99.00% and Kappa coefficient of 90.38% in water body extraction using Kompsat-5 image. The accuracy analysis indicates that the proposed WBTI method is less affected by the choice of threshold value and successfully maintains high overall accuracy and Kappa coefficient in wide threshold range.

• 반도체디스플레이기술학회지
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• 제21권3호
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• pp.39-44
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• 2022

The light extraction technology for improving the light efficiency of OLEDs is the core technology for extracting the light inside the OLEDs to the outside. This study demonstrates a simple method to generate random nanostructures (RNSs) containing high refractive index nanoparticles to improve light extraction and viewing angle characteristics. A simple dry low-temperature process makes the nanostructured scattering layer on the polymer resin widely used in the industry. The scattering layer has the shape of randomly distributed nanorods. To control optical properties, we focused on changing the shape and density of RNSs and adjusting the concentration of high refractive index nanoparticles. As a result, the film of the present invention exhibits a perpendicular transmittance of 85% at a wavelength of 550 nm. This film was used as a scattering layer to reduce substrate mode loss and improve EL efficiency in OLEDs.

• 로봇학회논문지
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• 제7권3호
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• pp.171-181
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• 2012

Outdoor mobile robots are faced with various terrain types having different characteristics. To run safely and carry out the mission, mobile robot should recognize terrain types, physical and geometric characteristics and so on. It is essential to control appropriate motion for each terrain characteristics. One way to determine the terrain types is to use non-contact sensor data such as vision and laser sensor. Another way is to use contact sensor data such as slope of body, vibration and current of motor that are reaction data from the ground to the tire. In this paper, we presented experimental results on terrain classification using contact sensor data. We made a mobile robot for collecting contact sensor data and collected data from four terrains we chose for experimental terrains. Through analysis of the collecting data, we suggested a new method of terrain feature extraction considering physical characteristics and confirmed that the proposed method can classify the four terrains that we chose for experimental terrains. We can also be confirmed that terrain feature extraction method using Fast Fourier Transform (FFT) typically used in previous studies and the proposed method have similar classification performance through back propagation learning algorithm. However, both methods differ in the amount of data including terrain feature information. So we defined an index determined by the amount of terrain feature information and classification error rate. And the index can evaluate classification efficiency. We compared the results of each method through the index. The comparison showed that our method is more efficient than the existing method.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2002년도 봄 학술발표논문집 Vol.29 No.1 (B)
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• pp.238-240
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• 2002

If there is an Information Retrieval system which comprehends the semantic content of documents and knows the preference of users. the system can search the information better on the Internet, or improve the IR performance. Therefore we propose the IR model which combines semantic based indexing and fuzzy relevance model. In addition to the statistical approach, we chose the semantic approach in indexing, lexical chains, because we assume it would improve the performance of the index term extraction. Furthermore, we combined the semantic based indexing with the fuzzy model, which finds out the exact relevance of the user preference and index terms. The proposed system works as follows: First, the presented system indexes documents by the efficient index term extraction method using lexical chains. And then, if a user tends to retrieve the information from the indexed document collection, the extended IR model calculates and ranks the relevance of user query. user preference and index terms by some metrics. When we experimented each module, semantic based indexing and extended fuzzy model. it gave noticeable results. The combination of these modules is expected to improve the information retrieval performance.

• 한국응용과학기술학회지
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• 제36권1호
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• pp.113-124
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• 2019

The purpose of the study was to investigate the effects of sea cucumber extract on skin as a natural cosmetics functional material. Subjective evaluation of cosmetics before and after were conducted with questionnaires regarding moisture content, sebum content, melanin index, and erythema index. Experiments were conducted on improvement efficacy using skin clinical trials and questionnaires to evaluate changes in perception of skin condition and efficiency of products. With the aim of minimizing skin irritation, the efficiency of the solvent used for extraction was an important factor, and the sea cucumber extract was harvested with efficient extraction conditions at a ratio of 1:10 of 50% ethanol. The study aimed to identify the suitability of sea cucumber extract as a functional cosmetics material to improve the moisturizing ability of skin and its effect on the skin by adding marine natural animal sea cucumber extract. Clinical studies on cosmetics skin containing sea cucumber extract, excellent skin improvement effect from all items of clinical experiment in experimental and control groups. Sea cucumber extract was proved to be a stable, non-adverse physiologically active substance against abnormal symptoms or side effects of skin reactions and skin problems. In addition, the study found excellent results that can lead to its use as a cosmetics material. This is expected to contribute to the development of various cosmetics industries.

• ETRI Journal
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• 제36권5호
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• pp.847-855
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• 2014

We developed a highly refractive index planarization layer showing a very smooth surface for organic light-emitting diode (OLED) light extraction, and we successfully prepared a highly efficient white OLED device with an embossed nano-structure and highly refractive index planarization layers. White OLEDs act as an internal out-coupling layer. We used a spin-coating method and two types of $TiO_2$ solutions for a planarization of the embossed nano-structure on a glass substrate. The first $TiO_2$ solution was $TiO_2$ sol, which consists of $TiO_2$ colloidal particles in an acidic aqueous solution and several organic additives. The second solution was an organic and inorganic hybrid solution of $TiO_2$. The surface roughness ($R_a$) and refractive index of the $TiO_2$ planarization films on a flat glass were 0.4 nm and 2.0 at 550 nm, respectively. The J-V characteristics of the OLED including the embossed nano-structure and the $TiO_2$ planarization film were almost the same as those of an OLED with a flat glass, and the luminous efficacy of the aforementioned OLED was enhanced by 34% compared to that of an OLED with a flat glass.

• 대한치과교정학회지
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• 제20권1호
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• pp.183-195
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• 1990

The purposes of present study were to identify possible relationships between post-treatment changes and post-retention changes. The patient's models were composed of 58 samples, and were classified non-extraction group (30 samples) and extraction group (28 samples). For each sample the first models were taken prior to the start of treatment, the second models just after the end of treatment, and the third models two years after. The results were as follows: 1. In the cases of non-extraction group, increases were in intermolar width of maxilla, interbicuspid width of maxilla and arch perimeter of mandible during treatment period, but decreases were in the same measurements during post-retention period. 2. In the cases of extraction group, decreases were in intermolar width of mandible, interbicuspid widths of maxilla and mandible, arch length of mandible, arch perimeters of maxilla and mandible during treatment period. 3. Significant decreases were in the irregularity index of both extraction and non-extraction group during treatment period. 4. There were significant differences of arch dimensional changes in intermolar widths of maxilla and mandible, interbicuspid widths of maxilla and mandible, arch lengths of maxilla and mandible, arch perimeters of maxilla and mandible between non-extraction and extraction group.

• Journal of Biosystems Engineering
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• 제22권4호
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• pp.433-438
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• 1997

The freshness of apple was evaluated by characterizing the surface texture of flesh cells. The freshness index which was related to the amount of wrinkles on the cell surface was defined to quantify the freshness. Four parameters relevant to the amount of the cell wrinkles were selected and measured using image analysis including wrinkle extraction procedure and Fast Fourier Transform of a wrinkle-extracted image. Out of 4 parameters, three parameters had highly significant correlations with the time elapsed after harvest. But it was concluded that two parameters out of such 3 parameters could be used for description of freshness index.

• 한국광학회지
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• 제22권1호
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• pp.53-57
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• 2011

본 논문에서는 통상적인 LED 구조 위에 추가적으로 상부 층을 형성하여 LED의 광 추출 효율을 개선하였다. 상부 층의 두께 및 굴절률 변화에 따른 LED의 광 방출 특성을 전산모사하였고 광 추출 효율이 개선되는 조건을 분석하였다. 약 1.05~1.40의 굴절률 범위에서 LED의 광방출이 증가하였다. 또한, 이 범위에서 두께가 증가할수록 광방출이 증가하였다. 굴절률이 1.30@589.3 nm인 인덱스 매칭 액체를 실제 LED의 상부 층으로 형성하여 LED의 광 추출 효율이 약 22% 정도 향상됨을 실험적으로 보였다. 이렇게 LED 위에 상부 층을 형성하는 개념은 간단하게 LED의 광 추출 효율을 개선할 수 있을 것으로 기대된다.