• Korean Journal of Radiology
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• 제21권5호
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• pp.561-571
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• 2020

Objective: To evaluate the clinical utility of ultrafast dynamic contrast-enhanced (DCE)-MRI compared to conventional DCE-MRI by studying lesion conspicuity and size according to the level of background parenchymal enhancement (BPE). Materials and Methods: This study included 360 women (median age, 54 years; range, 26-82 years) with 361 who had undergone breast MRI, including both ultrafast and conventional DCE-MRI before surgery, between January and December 2017. Conspicuity was evaluated using a five-point score. Size was measured as the single maximal diameter. The Wilcoxon signed-rank test was used to compare median conspicuity score. To identify factors associated with conspicuity, multivariable logistic regression was performed. Absolute agreement between size at MRI and histopathologic examination was assessed using the intraclass correlation coefficient (ICC). Results: The median conspicuity scores were 5 at both scans, but the interquartile ranges were significantly different (5-5 at ultrafast vs. 4-5 at conventional, p < 0.001). Premenopausal status (odds ratio [OR] = 2.2, p = 0.048), non-mass enhancement (OR = 4.1, p = 0.001), moderate to marked BPE (OR = 7.5, p < 0.001), and shorter time to enhancement (OR = 0.9, p = 0.043) were independently associated with better conspicuity at ultrafast scans. Tumor size agreement between MRI and histopathologic examination was similar for both scans (ICC = 0.66 for ultrafast vs. 0.63 for conventional). Conclusion: Ultrafast DCE-MRI could improve lesion conspicuity compared to conventional DCE-MRI, especially in women with premenopausal status, non-mass enhancement, moderate to marked BPE or short time to enhancement.

• 디지털융복합연구
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• 제10권3호
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• pp.173-178
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• 2012

본 논문에서는 영상의 관심 영역을 선택추출하여 효과적으로 객체를 추출 할 수 있는 관심 영역 지도(Saliency Map) 생성 기법을 제안하였다. 제안하는 방법은 객체의 윤곽선에 초점을 맞추어 단일영상의 에지(Edge), HSV 색상 모델의 H(Hue)성분, 포커스(Focus), 엔트로피(Entropy)의 네 가지 특징 정보를 이용한 각각의 특징 지도(Feature Map)를 생성하고, 생성된 특징 지도들을 중심 주변 차이(Center Surround Differences)를 이용하여 중요도 지도(conspicuity map)를 생성하게 된다. 이후 생성된 중요도 지도들을 조합함으로써 관심 영역 지도를 생성하게 된다. 제안한 기법을 이용하여 생성한 관심 영역 지도를 기존 기법의 관심 영역 지도와 비교한 결과 제안한 기법의 우수함을 알 수 있었다.

• 한국정밀공학회지
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• 제25권2호
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• pp.131-139
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• 2008

This paper presents a new saliency map which is constructed by providing dynamic weights on individual features in an input image to search ROI(Region Of Interest) or FOA(Focus Of Attention). To construct a saliency map on there is no a priori information, three feature-maps are constructed first which emphasize orientation, color, and intensity of individual pixels, respectively. From feature-maps, conspicuity maps are generated by using the It's algorithm and their information quantities are measured in terms of entropy. Final saliency map is constructed by summing the conspicuity maps weighted with their individual entropies. The prominency of the proposed algorithm has been proved by showing that the ROIs detected by the proposed algorithm in ten different images are similar with those selected by one-hundred person's naked eyes.

• 대한토목학회논문집
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• 제32권5D호
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• pp.437-444
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• 2012

본 논문은 공사구간에서 사용되고 있는 교통안전표지의 생상과 관련된 문제점 분석 및 해외사례 검토를 바탕으로 공사구간에서 운전자들의 보다 안전한 주행을 도모하기 위해 공사구간 내의 교통안전표지에 형광 주황색을 적용하는 것에 대한 타당성을 평가하고자 한다. 이를 위해, 먼저 현재 공사구간에서 사용되고 있는 교통안전표지의 근본적인 형상과 색상을 검토하였다. 또한 형광 주황색을 이용하여 공사구간 교통안내시설을 제작한 후 실내 육안 평가 및 주행 시뮬레이터를 이용해 형광 주황색 사용의 효과를 측정하였다. 실내 육안 평가 결과, 현재 고속도로에서 사용 중인 황색 바탕의 흑색 글씨 또는 일반국도 등에서 사용 중인 백색 바탕의 적색 글씨로 제작된 공사구간 표지와 비교하였을 때 형광 주황색 바탕에 흑색 글씨로 제작된 안내표지, 예고표지, 갈매기표지 그리고 유도표지가 주목성 측면에서 모두 70% 이상의 선호도를 보이고 있는 것을 확인하였다. 또한 주행 시뮬레이터를 이용한 실험에서는 본 연구에서 제안하는 형광 주황색 바탕, 고속도로에서 사용 중인 황색 바탕, 그리고 일반국도 등에서 사용 중인 백색 바탕의 공사구간 안내표지를 비교하였다. 비교 결과 형광 주황색 바탕의 안내표지가 황색 바탕 안내표지 보다는 15m 전방에서, 그리고 백색 바탕 안내표지보다는 25m 전방에서 인지됨을 확인하였다.

• Korean Journal of Radiology
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• 제22권4호
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• pp.502-512
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• 2021

Objective: To objectively and subjectively assess and compare the characteristics of monoenergetic images [MEI (+)] and polyenergetic images (PEI) acquired by dual-energy CT (DECT) of patients with breast cancer. Materials and Methods: This retrospective study evaluated the images and data of 42 patients with breast cancer who had undergone dual-phase contrast-enhanced DECT from June to September 2019. One standard PEI, five MEI (+) in 10-kiloelectron volt (keV) intervals (range, 40-80 keV), iodine density (ID) maps, iodine overlay images, and Z effective (Z_eff) maps were reconstructed. The contrast-to-noise ratio (CNR) and the signal-to-noise ratio (SNR) were calculated. Multiple quantitative parameters of the malignant breast lesions were compared between the arterial and the venous phase images. Two readers independently assessed lesion conspicuity and performed a morphology analysis. Results: Low keV MEI (+) at 40-50 keV showed increased CNR and SNR_{breast lesion} compared with PEI, especially in the venous phase ([CNR: 40 keV, 20.10; 50 keV, 14.45; vs. PEI, 7.27; p < 0.001], [SNR_{breast lesion}: 40 keV, 21.01; 50 keV, 16.28; vs. PEI, 10.77; p < 0.001]). Multiple quantitative DECT parameters of malignant breast lesions were higher in the venous phase images than in the arterial phase images (p < 0.001). MEI (+) at 40 keV, ID, and Z_eff reconstructions yielded the highest Likert scores for lesion conspicuity. The conspicuity of the mass margin and the visual enhancement were significantly better in 40-keV MEI (+) than in the PEI (p = 0.022, p = 0.033, respectively). Conclusion: Compared with PEI, MEI (+) reconstructions at low keV in the venous phase acquired by DECT improved the objective and subjective assessment of lesion conspicuity in patients with malignant breast lesions. MEI (+) reconstruction acquired by DECT may be helpful for the preoperative evaluation of breast cancer.

• 전자공학회논문지SC
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• 제44권1호
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• pp.50-58
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• 2007

본 논문에서는 로봇이 태스크와 관련된 부분에 시각 집중을 하도록 하기 위해서 기존의 상향식 주목 알고리즘을 확장한 질의 기반 시각 집중 알고리즘을 제안한다. 질의 기반 시각 집중 알고리즘은 로봇이 수행 할 태스크와 관련한 물체를 질의하면 그 물체의 속성을 분석하여 여러 종류의 도드라짐(Conspicuity) 영상 지도에 적용될 가중치 값을 작성한다. 그리고 가중치를 이용하여 도드라짐 영상 지도를을 합성한 Saliency 영상 지도를 작성하여 기존의 주목 알고리즘과 비교 평가를 수행하였다. 여기서는 일예로서 질의 물체의 속성을 색으로 사용하였다.

• 가정과삶의질연구
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• 제30권3호
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• pp.105-118
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• 2012

This study aims to recognize cognition of credit card and shopping value in contemporary society, cognition of credit card and shopping value according to types of consumption orientation, and factors that influence cognition of credit card and shopping value, and ultimately provide a foundation for establishing proper shopping value. A total of 453 women and men residing in Seoul have been set as research object in order to achieve the purpose of the study. The data was analyzed by Cronbach' alpha, frequencies, percentile, mean, factor analysis, K-mean cluster analysis, t-test, ANOVA and Duncan's multiple range test, multiple linear regression. All analysis progress was done by spsswin12.0 statistics program. A summary of this research goes as follows: First, categorization of consumption orientation lead to two clusters of rational and symbolic & conspicuity consumption patterns and cognition of credit card was categorized into positive and negative cognition and shopping value was categorized into hedonic shopping value, utilitarian shopping value and time-save shopping value. Second, rational shoppers had high utilitarian shopping values and symbolic & conspicuity shoppers had high both hedonic shopping values and utilitarian shopping values. Third, the most influential factor in hedonic shopping value and utilitarian was consumption orientation. In conclusion, this research has showed that cognition of credit card and shopping value according to types of consumption orientation patterns varied, and that consumption orientation was an influential factor on cognition of credit card and shopping value.

• 한국도로학회논문집
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• 제8권4호
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• pp.1-11
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• 2006

현재 국도개량사업으로 국도의 이동성이 향상되었으나 유출부에 설치된 도로안전시설인 시선유도시설은 일관성 없이 설치되거나 미설치된 경우가 많다. 유출부의 시선유도시설은 유출부의 안전성을 높이는 시설임에도 불구하고 각 유출부마다 서로 다른 유형으로 설치되어 그 기능적 검토가 필요할 것으로 판단하였다. 이에 본 연구에서는 현장조사를 통하여 조사된 시설유형별로 설치기준의 적합성을 검토한 후 운전자 인지특성을 고려한 효과적인 시설유형을 제시하고자 하였다. 이를 위하여 3D-시뮬레이션을 개발하여 보다 객관적인 비교실험을 수행하였다. 시설유형 간 비교변수는 운전자 인지특성을 대변할 수 있는 현저성, 시인성으로 선정하여 시설유형에 대한 각각의 특성실험을 수행하였으며 인지 특성변수로 채택된 시인성의 실험에 대한 피 실험자의 측정오차를 줄이기 위하여 초점기록계(Eye Marker Recorder)를 이용하여 실험함으로서 보다 정량적이고, 객관적인 주시빈도를 측정할 수 있었다. 각각의 측정 변수들에 대한 시설유형 간 유의성을 검증하기 위하여 분산 분석으로 검토하였다. 그 결과 현저성은 시설유형 간 유의미한 차이를 나타냈으며, 유출부를 인지하는데 안전표지, 장애물표적표지, 시선유도등, 시선유도봉이 설치된 시설유형이 가장 유리한 것으로 평가되었다. 또한 시인성의 효과척도로 주시빈도를 측정한 결과 시설유형 간 유의미한 차이를 알 수 있었으며, 현저성과 동일한 시설유형이 설치되었을 때 유출부를 인지하는데 유리한 것으로 평가되었으며 전체적인 결과를 종합하여 볼 때 안전표지, 장애물표적표지, 시선유도등, 시선유도봉의 시설이 가장 유리한 것임을 알 수 있었다.

• Korean Journal of Radiology
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• 제21권9호
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• pp.1036-1044
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• 2020

Objective: To investigate the clinical feasibility of synthetic diffusion-weighted imaging (sDWI) at different b-values in patients with breast cancer by assessing the diagnostic image quality and the quantitative measurements compared with conventional diffusion-weighted imaging (cDWI). Materials and Methods: Fifty patients with breast cancer were assessed using cDWI at b-values of 800 and 1500 s/mm² (cDWI₈₀₀ and cDWI₁₅₀₀) and sDWI at b-values of 1000 and 1500 s/mm² (sDWI₁₀₀₀ and sDWI₁₅₀₀). Qualitative analysis (normal glandular tissue suppression, overall image quality, and lesion conspicuity) was performed using a 4-point Likert-scale for all DWI sets and the cancer detection rate (CDR) was calculated. We also evaluated cancer-to-parenchyma contrast ratios for each DWI set in 45 patients with the lesion identified on any of the DWI sets. Statistical comparisons were performed using Friedman test, one-way analysis of variance, and Cochran's Q test. Results: All parameters of qualitative analysis, cancer-to-parenchyma contrast ratios, and CDR increased with increasing b-values, regardless of the type of imaging (synthetic or conventional) (p < 0.001). Additionally, sDWI₁₅₀₀ provided better lesion conspicuity than cDWI₁₅₀₀ (3.52 ± 0.92 vs. 3.39 ± 0.90, p < 0.05). Although cDWI₁₅₀₀ showed better normal glandular tissue suppression and overall image quality than sDWI₁₅₀₀ (3.66 ± 0.78 and 3.73 ± 0.62 vs. 3.32 ± 0.90 and 3.35 ± 0.81, respectively; p < 0.05), there was no significant difference in their CDR (90.0%). Cancer-to-parenchyma contrast ratios were greater in sDWI₁₅₀₀ than in cDWI₁₅₀₀ (0.63 ± 0.17 vs. 0.55 ± 0.18, p < 0.001). Conclusion: sDWI₁₅₀₀ can be feasible for evaluating breast cancers in clinical practice. It provides higher tumor conspicuity, better cancer-to-parenchyma contrast ratio, and comparable CDR when compared with cDWI₁₅₀₀.

• 방사선산업학회지
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• 제17권4호
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• pp.397-403
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• 2023

The purpose of this study is to obtain brain MRI images through Heavenly T₂ FLAIR and DWI techniques to find out strengths and weaknesses of each image. Data were analyzed on 13 normal people and 17 brain tumor patients. Philips Ingenia 3.0TCX was used as the equipment used for the inspection, and 32 Channel Head Coil was used to acquire data. Using Image J and Infinity PACS Data, 3mm² of gray matter, white matter, cerebellum, basal ganglia, and tumor areas were set and measured. Quantitative analysis measured SNR and CNR as an analysis method, and qualitative analysis evaluated overall image quality, lesion conspicuity, image distortion, susceptibility artifact and ghost artifact on a 5-point scale. The statistical significance of data analysis was that Wilcox-on Signed Rank Test and Paired t-test were executed, and the statistical program used was SPSS ver.22.0 and the p value was less than 0.05. In quantitative analysis, the SNR of gray matter, white matter, cerebellum, basal ganglia, and tumor of Heavily T₂ FLAIR is 41.45±0.13, 40.52±0.45, 41.44±0.51, 40.96±0.09, 35.28±0.46 and the CNR is 15.24±0.13, 16.75±0.23, 16.28±0.41, 15.83±0.17, 16.63±0.51. In DWI, SNR is 32.58±0.22, 36.75±0.17, 30.21±0.19, 35.83±0.11, 43.29±0.08, and CNR is 13.14±0.63, 14.21±0.31, 12.95±0.32, 11.73±0.09, 17.56±0.52. In normal tissues, Heavenly T₂ FLAIR obtained high results, but in disease evaluation, high results were obtained at DWI, b=1000 (p<0.05). In addition, in the qualitative analysis, overall image quality, lesion conspicuity, image distortion, susceptibility artifact and ghost artifact aspects of the Heavily T₂ FLAIR were evaluated, and 3.75±0.28, 2.29±0.24, 3.86±0.23, 4.08±0.21, 3.79±0.22 values were found, respectively, and 2.53±0.39, 4.13±0.29, 1.90±0.20, 1.81±0.21, 1.52±0.45 in DWI. As a result of qualitative analysis, overall image quality, image distortion, susceptibility artifact and ghost artifact were rated higher than DWI. However, DWI was evaluated higher in lesion conspicuity (p<0.05). In normal tissues, the level of Heavenly T₂ FLAIR was higher, but the DWI technique was higher in the evaluation of the disease (tumor). The two results were necessary techniques depending on the normal site and the location of the disease. In conclusion, statistically significant results were obtained from the two techniques. In quantitative and qualitative analysis, the two techniques had advantages and disadvantages, and in normal and disease evaluation, the two techniques produced useful results. These results are believed to be educational data for clinical basic evaluation and MRI in the future.