• Title/Summary/Keyword: remote assessment

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Linear Feature Extraction from Satellite Imagery using Discontinuity-Based Segmentation Algorithm

  • Niaraki, Abolghasem Sadeghi;Kim, Kye-Hyun;Shojaei, Asghar
    • Proceedings of the KSRS Conference
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    • v.2
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    • pp.643-646
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    • 2006
  • This paper addresses the approach to extract linear features from satellite imagery using an efficient segmentation method. The extraction of linear features from satellite images has been the main concern of many scientists. There is a need to develop a more capable and cost effective method for the Iranian map revision tasks. The conventional approaches for producing, maintaining, and updating GIS map are time consuming and costly process. Hence, this research is intended to investigate how to obtain linear features from SPOT satellite imagery. This was accomplished using a discontinuity-based segmentation technique that encompasses four stages: low level bottom-up, middle level bottom-up, edge thinning and accuracy assessment. The first step is geometric correction and noise removal using suitable operator. The second step includes choosing the appropriate edge detection method, finding its proper threshold and designing the built-up image. The next step is implementing edge thinning method using mathematical morphology technique. Lastly, the geometric accuracy assessment task for feature extraction as well as an assessment for the built-up result has been carried out. Overall, this approach has been applied successfully for linear feature extraction from SPOT image.

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Concept Design of Fire Safety Module for SV20 Service in the Korean e-Navigation System

  • Kim, Byeol;Moon, Serng-Bae;Hwang, Kwang-Il
    • Journal of Navigation and Port Research
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    • v.42 no.5
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    • pp.323-330
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    • 2018
  • The Korean e-Navigation system is a Korean approach to correspond with implementation of IMO e-Navigation. It provides five services, among them SV20 service, a ship remote monitoring system that collects and processes sensor information related to fire, navigation, and seakeeping performance safety. The system also detects abnormal conditions such as fires, capsizing, sinking, navigation equipment failure during navigation, and calculates the safety index and determines the emergency level. According to emergency level, it provides appropriate emergency response guidance for the onboard operator. The fire safety module is composed of three sub-modules; each module is the safety index sub-module, the emergency level determination sub-module and emergency response guidance sub-module. In this study, operational concept of the fire safety module in SV20 service is explained, and fire safety assessment factors are estimated, to calculate the fire safety index. Fire assessment factors included 'Fire detector position factor,' 'Smoke diffusion rate factor,' and 'Fire-fighting facilities factor.'

A Development and Performance Test of Voltage Measurement Accuracy Assessment System for Distribution Equipment (배전기기 전압계측 정밀도 평가시스템 개발 및 성능시험)

  • Cho, Jin-Tae;Kim, Ju-Yong;Lee, Hak-Ju;Kim, Jae-Han
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.27 no.9
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    • pp.83-89
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    • 2013
  • Power distribution system has been changed from radial system to closed loop or mesh system due to connection of distributed generation growth. Data from distribution equipments which are installed at distribution line is required to be accurate for the performance of DMS(Distribution Management System). This paper analyzes the voltage measurement data from distribution equipment. However, the results of the analysis are confirmed to have some errors in voltage measurement data from distribution equipment. These errors come from aging of voltage sensor in distribution equipment and inaccurate data transfer to FRTU(feeder remote terminal unit) through the controller. The main problem is that the voltage measurement data of distribution equipment can not be assessed after it's first installation at the distribution line. The voltage measurement accuracy assessment system is to assess the voltage measurement data from distribution equipment on hot-line. This study had a field test to verify the performance of system.

Environmental Impact Assessment and Environmental Monitoring in Korea (한국에서의 환경영향평가와 환경측정)

  • Kang, In-Goo;Kim, Myung-Jin
    • Journal of Environmental Impact Assessment
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    • v.4 no.3
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    • pp.31-39
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    • 1995
  • Environmental Impact Assessment (EIA) is composed of various procedures, such as screening, scoping, inventory survey, prediction, assessment, alternative assessment, mitigation measures, and post management. Environmental monitoring data for air quality or water quality, etc. is applied in the EIA process, especially in prediction and post management. As an effective tool of environmental monitoring, the remote sensing method, introduced recently, was used in collecting nationwide data concerning ecosystem and land use. This article explains the current monitoring status in Korea. Monitoring factors include air quality, water quality, soil, ocean, odor, noise, and ecosystems. This report explains the organization of the environmental monitoring system managed by the Ministry of Environment in Korea. Furthermore, it shows the environmental criteria and environmental policies applied to EIA in Korea.

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Radiometric Cross Calibration of KOMPSAT-3 and Lnadsat-8 for Time-Series Harmonization (KOMPSAT-3와 Landsat-8의 시계열 융합활용을 위한 교차검보정)

  • Ahn, Ho-yong;Na, Sang-il;Park, Chan-won;Hong, Suk-young;So, Kyu-ho;Lee, Kyung-do
    • Korean Journal of Remote Sensing
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    • v.36 no.6_2
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    • pp.1523-1535
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    • 2020
  • In order to produce crop information using remote sensing, we use classification and growth monitoring based on crop phenology. Therefore, time-series satellite images with a short period are required. However, there are limitations to acquiring time-series satellite data, so it is necessary to use fusion with other earth observation satellites. Before fusion of various satellite image data, it is necessary to overcome the inherent difference in radiometric characteristics of satellites. This study performed Korea Multi-Purpose Satellite-3 (KOMPSAT-3) cross calibration with Landsat-8 as the first step for fusion. Top of Atmosphere (TOA) Reflectance was compared by applying Spectral Band Adjustment Factor (SBAF) to each satellite using hyperspectral sensor band aggregation. As a result of cross calibration, KOMPSAT-3 and Landsat-8 satellites showed a difference in reflectance of less than 4% in Blue, Green, and Red bands, and 6% in NIR bands. KOMPSAT-3, without on-board calibrator, idicate lower radiometric stability compared to ladnsat-8. In the future, efforts are needed to produce normalized reflectance data through BRDF (Bidirectional reflectance distribution function) correction and SBAF application for spectral characteristics of agricultural land.

Automatic Road Extraction by Gradient Direction Profile Algorithm (GDPA) using High-Resolution Satellite Imagery: Experiment Study

  • Lee, Ki-Won;Yu, Young-Chul;Lee, Bong-Gyu
    • Korean Journal of Remote Sensing
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    • v.19 no.5
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    • pp.393-402
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    • 2003
  • In times of the civil uses of commercialized high-resolution satellite imagery, applications of remote sensing have been widely extended to the new fields or the problem solving beyond traditional application domains. Transportation application of this sensor data, related to the automatic or semiautomatic road extraction, is regarded as one of the important issues in uses of remote sensing imagery. Related to these trends, this study focuses on automatic road extraction using Gradient Direction Profile Algorithm (GDPA) scheme, with IKONOS panchromatic imagery having 1 meter resolution. For this, the GDPA scheme and its main modules were reviewed with processing steps and implemented as a prototype software. Using the extracted bi-level image and ground truth coming from actual GIS layer, overall accuracy evaluation and ranking error-assessment were performed. As the processed results, road information can be automatically extracted; by the way, it is pointed out that some user-defined variables should be carefully determined in using high-resolution satellite imagery in the dense or low contrast areas. While, the GDPA method needs additional processing, because direct results using this method do not produce high overall accuracy or ranking value. The main advantage of the GDPA scheme on road features extraction can be noted as its performance and further applicability. This experiment study can be extended into practical application fields related to remote sensing.

2-Step Structural Damage Analysis Based on Foundation Model for Structural Condition Assessment (시설물 상태평가를 위한 파운데이션 모델 기반 2-Step 시설물 손상 분석)

  • Hyunsoo Park;Hwiyoung Kim ;Dongki Chung
    • Korean Journal of Remote Sensing
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    • v.39 no.5_1
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    • pp.621-635
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    • 2023
  • The assessment of structural condition is a crucial process for evaluating its usability and determining the diagnostic cycle. The currently employed manpower-based methods suffer from issues related to safety, efficiency, and objectivity. To address these concerns, research based on deep learning using images is being conducted. However, acquiring structural damage data is challenging, making it difficult to construct a substantial amount of training data, thus limiting the effectiveness of deep learning-based condition assessment. In this study, we propose a foundation model-based 2-step structural damage analysis to overcome the lack of training data in image-based structural condition assessments. We subdivided the elements of structural condition assessment into instantiation and quantification. In the quantification step, we applied a foundation model for image segmentation. Our method demonstrated a 10%-point increase in mean intersection over union compared to conventional image segmentation techniques, with a notable 40%-point improvement in the case of rebar exposure. We anticipate that our proposed approach will enhance performance in domains where acquiring training data is challenging.

Landcover Analysis of DMZ and the Vicinity Using Remote Sensing and GIS Techniques (원격탐사와 GIS기법을 이용한 접경지역 토지피복연구)

  • Seo, Chang-Wan;Jeon, Seong-Woo
    • Journal of Environmental Impact Assessment
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    • v.7 no.1
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    • pp.11-22
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    • 1998
  • In Korea, the Demilitarized Zone(Hereafter DMZ) and the vicinity have special importance for a natural ecosystem research. However, We have difficulty in studying this region due to the access control. The purpose of this study is to analyze the landcover and the vegetation status of DMZ and the vicinity using remote sensing and GIS techniques. The site was divided into two regions; less than 2km from DMZ and less than 10 km from DMZ. The analyzed results of this study are as follow. First, the result of vegetation analysis is that the region of South and North Korea are similar in the area less than 2km from DMZ. However, the region of South Korea have good vegetation status than the region of South Korea in the area less than 10km from DMZ. Second, the result of landcover analysis is that the ratio of the landcover of South and North Korea decreased forest, agricultural and grass, built-up, barren area by turns in the area less than 2km from DMZ. However, the built-up area of South Korea increased as much as the forest area decreased and the other areas of North Korea increased as much as the forest area decreased in the area less than 10 km from DMZ. There are some differences in landcover between analyzed result and an existing statistical data. The causes are using one season setellite images, and an existing statistical data with landuse types. The analysis using remote sensing and GIS techniques is the most suitable method to understand the landcover and vegetation status of DMZ and the vicinity. Further studies are expected to overcome the limitation of this study.

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Development of a real-time mobile gamma-ray measurement system for shipboard use

  • Chang-Jong Kim;Mee Jang;Hyuncheol Kim;Jong-Myoung Lim;Wanno Lee;Gyu-Seong Cho
    • Nuclear Engineering and Technology
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    • v.55 no.11
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    • pp.4077-4082
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    • 2023
  • Large areas must be rapidly screened to monitor radiation in marine environments. For this purpose, this study developed a mobile real-time gamma-ray measurement system for shipboard use and evaluated its performance. The system was developed to measure engine or generator cooling water by installing a canister inside the ship. The minimum detectable activity of the system is about 0.8 Bq/L for a 60 s measurement period, and real-time data transmission and remote control are possible. The system was tested in the field and is currently being installed and operated on ships in service. Such a ship-based real-time gamma-radiation measurement system is suitable for a wide range of marine radiation surveillance applications and is expected to be rapidly deployed.