점사상 밀도 분석을 위한 L-지표의 적용

이병길,Lee, Byoung-Kil 한국공간정보학회 2008 한국공간정보학회지 Vol.16 No.2

지도좌표를 가진 정보의 통계적 분석은 GIS 중요기능 중 하나로 인정되고 있다. 그 중 가장 기본적인 분석의 하나로 점사상에 대한 밀도분석이 이루어지고 있다. 밀도분석은 일반적으로 라스터 분석의 일부로 간주되고 있으며, 적합한 밀도분석을 위해서는 kernel 반경으로 알려진 검색반경의 결정이 중요한 것으로 알려져 있다. 본 연구에서는 기존 연구 결과에서 검색반경 설정에 유용한 것으로 알려진 L-지표를 이용하여, 비즈니스 GIS 분야에 축적된 점사상의 밀도 분석에 적합한 반경을 추정하고, 추정된 결과를 기반으로 점사상의 특성에 따른 L-지표의 거동을 고찰하였다. 연구결과 점사상이 대상지역의 일부 지역에서 크게 밀집되는 경우에는 L-지표가 대상지역의 크기와 무관하게 일정한 반경에서 극대값을 보이기 때문에 L-지표를 이용하여 검색반경을 설정하는 것이 유용함을 알 수 있었다. 반면, 점사상이 대상지역에 고루 분포하는 경우에는 L-지표의 극대값이 나타나는 반경이 대상지역의 크기에 따라 영향을 받기 때문에 L-지표를 이용하여 검색반경을 설정하는 것이 적합하지 않음을 알 수 있었다. 따라서 L-지표를 이용한 점사상 밀도의 검색반경 설정에는 점사상의 분포특성이 고려되어야 함을 알 수 있었다. Statistical analysis of the coordinate information is regarded as one of the major GIS functions. Among them, one of the most fundamental analysis is density analysis of point features. For analyzing the density appropriately, determining the search radius, kernel radius, has critical importance. In this study, using L-index, known as its usefulness for choosing the kernel radius in previous researches, radius for density analysis of various point features are estimated, and the behavior of L-index is studied based on the estimated results. As results, L-index is not suitable to determine the search radius for the point features that are evenly distributed with small clusters, because the pattern of the L-index is depends on the size of the study area. But for the point features with small number of highly clustered areas, L-index is suitable, because the pattern of the L-index is not affected by the size of study area.

순수 유두 갑상선암과 소포 변이 유두 갑상선암: 임상병리학적 특성 비교 연구

이병길,윤현조,정성후,Byoung Kil Lee,M.D.,Hyun Jo Youn,M.D. and Sung Hoo Jung,M.D. 대한갑상선-내분비외과학회 2009 The Koreran journal of Endocrine Surgery Vol.9 No.1

Purpose: Pure papillary thyroid carcinoma (PPTC) and the follicular variant of papillary thyroid carcinoma (FVPTC) are the most common subtypes of papillary thyroid carcinoma (PTC). The aim of this study was to investigate if there are any differences in clinicopathological features of these two subgroups. Methods: We performed a retrospective chart review of patients who were treated for PPTC and FVPTC between September 2003 and April 2008. Four hundred fifty patients were shown to have PPTC (91.8%) and forty (8.2%) had FVPTC after a histologic review. The two groups were compared in terms of the clinicopathologic features and the results of preoperative ultrasonography (USG), the fine needle aspiration cytology (FNAC), the frozen section biopsy and the surgical treatment. Results: The tumor size was significantly larger in the FVPTC group than in the PPTC group (1.47 cm versus 1.08 cm, respectively P=0.024). However, both groups had similar clinicopathologic features in terms of age, gender, capsular invasion, multifocality, lymph node metastasis, the MACIS score and the TNM stage. Further, the operative method did not differ between the two groups. The sensitivities of USG and frozen section biopsy for diagnosing FVPTC were significantly lower than those for PPTC (53.85% versus 72.95%, respectively, P=0.045, 81.58% versus 97.25%, respectively, P=0.049). Conclusion: The FVPTC group presented with a larger tumor size, and the clinicopathologic features of the FVPTC group did not significantly differ from those of the PPTC group. Although further studies with longer follow-up are required, these results suggest that the patients in both groups should be treated identically. (Korean J Endocrine Surg 2009;9:19-23)

공간분포지표를 이용한 위성영상 분류오차의 공간적 분포 평가

이병길(Lee, Byoung-Kil),김용일(Kim, Yong-Il),어양담(Eo, Yong-Dam) 한국측량학회 1999 한국측량학회지 Vol.17 No.2

위성영상의 통계적 분류를 위한 유효 트레이닝 기법에 관한 연구

이병길(Lee, Byoung-Kil),김용일(Kim, Yong-Il),어양담(Eo, Yang-Dam) 한국측량학회 1999 한국측량학회지 Vol.17 No.3

점사상의 지역단위 집계가 K-지표에 미치는 영향

이병길(Lee, Byoung-Kil) 한국측량학회 2006 한국측량학회지 Vol.24 No.1

밀도구분도 매핑을 이용한 통계정보 공간 내삽의 유효성 평가

이병길(Lee, Byoung-Kil) 한국측량학회 2006 한국측량학회지 Vol.24 No.4

고해상도 위성영상을 위한 컴퓨터 응용 영상판독 시스템 개념설계

이병길(Lee Byoung-Kil),김용일(Kim Yong-Il),어양담(Eo Yang-Dam),박민호(Park Min-Ho) 대한토목학회 2000 대한토목학회논문집 D Vol.20 No.2D

토지 개발 적정성 평가를 위한 경사도 계산 방법 개선

이병길(Lee, Byoung Kil) 대한공간정보학회 2016 대한공간정보학회지 Vol.24 No.3

토지 개발 인허가 기준에는 중요 요소로서 경사도가 포함되어 있다. 토지 적성 평가 지침, 산지전용허가기준 등에는 수치지형도상 평가대상 토지의 평균경사도를 측정하여 경사도로 사용하며, GIS를 적용할 수 있다고 규정되어 있다. 입력 자료로는 국토지리정보원의 1/5,000 수치지형도 외에 한국토지정보시스템 전산자료를 활용 가능한 자료로 예시하고 있다. 경사도 계산에는 수치지형도의 등고선을 이용한 방법, 이를 DEM으로 변환하여 이용하는 방법 등 다양한 방법이 제시되고 있으나 표준화된 경사도 계산 방법은 제시되지 못하고 있어 실무에서 혼란이 발생하고 있다. 이러한 혼란을 감소시키기 위하여 본 연구에서는 표준화된 경사도 계산 방법과 적정 해상도를 결정할 수 있는 방안을 제안하고자 하였다. 경사도 계산에 사용되는 여러 방법을 분석한 결과, 지형의 복잡성을 고려하여 결정된 해상도를 가진 DEM을 만들어 유한차분법을 이용하여 평균경사도를 계산하는 개선된 방안을 제시하였다. Slope is one of the most important factor in land development permission standards. In guideline of 『Land Suitability Assessment』 or 『Forest Land Conversion Standard』, average slope can be measured using digital map and GIS for target area. Inputs in slope calculation are 1/5,000 digital map of NGII(National Geographic Information Institute) or digital information of Korea Land Information System. Many confusions occur in the field, as there is no standard for slope calculation and are lots of slope calculation methods using contour lines or DEM derived from them. Avoiding these confusions, this study was intended to propose a standardized method for slope calculation and a selection method for a suitable resolution. In this study, using DEM of optimum grid size according to the complexity of topography with finite difference method is suggested as improved slope calculation method, after comparing several representative slope calculation methods.

갑상선 촉지 종괴에서 시행한 세침흡인세포검사법, 동결절편검사법 및 초음파검사법의 진단적 유용성

이병길(Byoung Kil Lee),정성후(Sung Hoo Jung) 대한두경부종양학회 2002 대한두경부 종양학회지 Vol.18 No.2

Objectives: This study was done to determine the diagnostic efficacy of fine needle aspiration cytology (FNA), frozen section biopsy (FSx) and ultrasonography in a palpable thyroid mass. Materials and Methods: During the period from July 1999 to March 2002, the medical records of 98 patients who underwent a thyroidectomy for thyroid mass, at the Department of Surgery, Chonbuk National University Hospital, were reviewed retrospectively. Ninety eight cases were classified according to whether the FNA cytological diagnosis inadequate, benign, suspicious, or malignant and the FSx diagnosis benign or malignant and the ultrasonographic examination was benign, suspicious, or malignant. The diagnostic correlations of ultrasonography, FNA cytology, frozen section, and both FNA cytology and frozen section with definite histologic diagnosis were evaluated. Results: According to the FNA cytological interpretation, 76 cases were diagnosed as benign, 6 cases suspicious, 13 cases malignant, and 3 cases inadequate. The sensitivity and specificity for FNA were 86.3% and 95.9% and for FSx 95.5% and 100% respectively. The diagnostic accuracy of FNA and FSx were 93.5% and 98.9% respectively. Based on a definite histologic diagnosis, the ultrasonographic examination had a sensitivity and a specificity of 77.2% and 78.9%. Conclusion: The results confirm that FNA cytology is a reliable and useful tool in the initial evaluation of a palpable thyroid mass compared to the ultrasonographic examination. Intraoperative FSx is a valuable diagnostic procedure to confirm the cytological diagnosis with undetermined or unsatisfactory cytological diagnosis.

유두상 갑상선암에서 최소 갑상선외 침범의 의의

이병길(Byoung Kil Lee),이민주(Min Joo Lee),윤현조(Hyun Jo Youn),정성후(Sung Hoo Jung) 대한두경부종양학회 2009 대한두경부 종양학회지 Vol.25 No.1

Background and Objectives:In the TNM 6th classification system, extrathyroidal invasion of differentiated thyroid carcinoma has been classified into T3(minimal invasion), T4a(extended invasion), and T4b(more ex-tensive unresectable invasion) according to the degree and it has been recognized as an important prognostic factor. In this study, we investigated the prognostic significances of minimal extrathyroidal invasion in papillary thyroid carcinoma(PTC). Material and Methods:We retrospectively studied 221 patients who are underwent thyroidectomy due to PTC from September 2003 to December 2006. Fifty-four(24.4%) patients had a PTC with minimal extrathyroidal invasion(Group A) and 167(75.6%) patients had a PTC without extrathyroidal invasion(Group B). The existence of minimal extrathyroidal invasion was based on operative and pathological findings. Results:Minimal extrathyroidal invasion in PTC was related to tumor size, lymph node metastasis, and oper-ative method(p<0.001). But, there is no significant difference in age, gender, and multifocality between Group A and B. Hashimoto’s thyroiditis was observed more frequently in Group B(p=0.019). Conclusion:These findings suggest that minimal extrathyroidal invasion is related to poor prognostic factors in PTC. Therefore, aggressive surgical approach is required when there is evidence of minimal extrathyroidal invasion in preoperative radiologic examination or operative finding.