Earticle

Axial map analysis of Space Syntax is a well known technique on the interpretation of configurational space structure and has been successful to understand the relationships between space structures. This paper deals with the limitations of axial lines as a unit space to measure it's social logic due to the fact that axial lines are the fewest longest lines of visibility. This paper attempts to refine an axial space into more detailed unit to identify lines in a real-world manner so that the measured unit of a space can be more precisely correspond to its functions in a the world. Axial lines are split into a segment based on intersection points and can form a graph to get a relationship between them, which is called a 'segment line' and results in a 'segment map'. With comparing measurements of spaces in axial line map and segment map in a case of simulation, this segmentation method of space analysis will find a way to improvement of the space syntax techniques.

Purpose: To evaluate the repeatability of corneal epithelial thickness (CET) measurements in normal eyes and eyes diagnosed with corneal disease using the epithelial thickness map (ETM) of anterior-segment optical coherence tomography (OCT). Methods: In this retrospective study, patients with three OCT scans using the ETM mode of Cirrus OCT between October 2021 and January 2024 were reviewed. Two groups of subjects were included: (1) normal subjects with no history of ophthalmic surgery, corneal diseases, and topical antiglaucoma medication uses; and (2) subjects with corneal diseases including dry eye syndrome, recurrent corneal erosion, pterygium, and others. A total of 57 eyes of 57 normal subjects and 106 eyes of 76 patients with corneal disease were included. ETM was analyzed in 25 zones (one zone within 0?2 mm diameter, eight zones within 2?5 mm diameter, eight zones within 5?7 mm diameter, and eight zones within 7?9 mm diameter). Repeatability was evaluated by calculating intraclass correlation coefficient (ICC), coefficient of variation (CoV), within-subject standard deviation (Sw), and Bland-Altman plot. Results: Among a total of 25 sectors, the normal eyes showed high repeatability (ICC, >0.75; CoV, 2.160%?5.292%; Sw, 0.760? 1.653 μm) in 23 sectors, and corneal diseases patients also showed high repeatability (ICC, >0.75; CoV, 4.167%?9.606%; Sw, 1.298?3.340 μm) in 22 sectors. However, the wide range of 95% limit of agreement width of Bland-Altman plot presented in corneal disease group and some peripheral zones in normal eyes indicates some variability of CET measurements. Conclusions: Except for a few peripheral sectors, ETM of Cirrus OCT provides repeatable CET measurements in normal eyes; however in corneal disease group, repeatability was not consistently high. To measure CET accurately, performing multiple measurements is advised especially in patients with corneal disease and patients in whom peripheral CET values.

본 논문에서는 미지의 환경에서 이동 로봇이 주행 중 얻어진 격자지도(grid map)상의 장애물 정보를 이용하여 이동 로봇 주변환경을 직선선분으로 표현한다. 격자지도의 장애물 정보는 초음파 센서를 이용하여 얻어지므로 이동로봇과 인접한 장애물 정보만을 얻게된다. 얻어진 격자 정보를 호프변환을 이용하여 직선선분을 구축하고 이를 이전에 얻어진 직선선분과 결합하여 전체지도를 완성해 간다. 논의된 방법은 모의실험을 통하여 증명하였다.

알려지지 않은 환경에서 이동로봇이 목표점까지 이동하기 위해서는 외계센서를 이용하여 장애물을 인식하여 충돌 없이 주행할 수 있는 능력이 있어야하고 또한 인식된 장애물을 지도정보로 저장하여야 한다. 이렇게 생성된 지도정보를 이용하여 최적의 경로를 실시간으로 계획하면서 목표점까지 도달하여야 한다. 본 논문에서는 초음파 센서로 알려지지 않은 환경을 인식하여 선분지도를 생성하면서 생성된 선분지도를 이용하여 동적으로 최적의 경로계획을 위한 경로생성에 대하여 방법을 제시한다. 또한 실내 환경에서 모의실험을 통하여 실시간으로 경로계획이 가능함을 확인하였다.

The paper presents an efficient method of extracting line segment in a local map of a robot's surroundings. The local map is composed of 2-D grids that have both the occupancy and orientation probabilities using sonar sensors. To find the shape of an object in a local map from orientation information, the orientations are clustered into several groups according to their values. The line segment is , then, extracted from the clusters based on Hough transform. The proposed technique is illustrated by experiments in an indoor environment.