• Journal of the Korean Association of Geographic Information Studies
• /
• 제21권1호
• /
• pp.106-114
• /
• 2018

DEM(Digital Elevation Model) are now easily produced with advancing remote sensing technology. Depending on desired task, UAV can produce high resolution DEM. But high resolution comes with issues of data storage and processing time and cost. To check the effect of DEM resolution, this study compares six geomorphological parameters derived from different resolution DEM in a test area around Chuncheon, Korea. The comparison analysis was based on statistics of each derivatives of slope, curvature, flow direction, flow accumulation, flow length and basin. As a result, it was found that DEM remained unchanged and so did the flow accumulation area. However, slope, curvature, flow length and basin numbers were decreased with the normalization of increasing pixel size. DEM resolution should be carefully selected depending on the precision of application required.

• Journal of the Korean Society for Nondestructive Testing
• /
• 제16권3호
• /
• pp.155-161
• /
• 1996

For the condition monitoring of the journal bearing in rotating machinery, a system for their diagnosis by acoustic emission(AE) was developed. AE has been used to detect abnormal conditions in the bearing system. It was found from the field application study as well as the laboratory experiment using a simulated journal bearing system that AE RMS voltage was the most efficient parameter for the purpose of current study. Based on the above results, algorithms and judgement criteria for the diagnosis system was established. The system is composed of four parts as follows: the sensing part including AE sensor and preamplifier, the signal processing part for RMS-to-DC conversion to measure AE ms voltage, the interface part for transferring RMS voltage data into PC using A/D converter, and the software part including the graphic display of bearing conditions and the diagnosis program.

• Journal of Korean Society for Geospatial Information Science
• /
• 제20권4호
• /
• pp.135-143
• /
• 2012

Remote sensing which observes repeatedly the whole Earth and GIS-based decision-making technology have been utilized widely in disaster management such as early warning monitoring, damage investigation, emergent rescue and response, rapid recovery etc. In addition, various countermeasures of national level to collect timely satellite imagery in emergency have been considered through the operation of a satellite with onboard multiple sensors as well as the practical joint use of satellite imagery by collaboration with space agencies of the world. In order to respond heavy snowfall disaster occurred on the east coast of the Korean Peninsula in February 2011, snow-covered regions were analyzed and detected in this study through NDSI(Normalized Difference Snow Index) considering reflectance of wavelength for MODIS sensor and change detection algorithm using satellite imagery collected from International Charter. We present the application case of National Disaster Management Institute(NDMI) which supported timely decision-making through GIS spatial analysis with various spatial data and snow cover map.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• 제32권6호
• /
• pp.375-381
• /
• 2019

Structural health monitoring to determine structural conditions at an early stage and to efficiently manage the energy requirements of buildings using systems that collects relevant data, is under active investigation. Structural monitoring requires cutting-edge technology in which construction, sensing, and ICT technologies are combined. However, the scope of application is limited because expensive sensors and specialized technical skills are often required. In this study, a Raspberry Pi module, one of the most widely used single board computers, a Lora module that is capable of long-distance communication at low power, and a high-performance accelerometer are used to construct a wireless edge computing system that can monitor building response over an extended time period. In addition, the Raspberry Pi module utilizes an edge computing algorithm, and only meaningful data is obtained from the vast amount of acceleration data acquired in real-time. The raw data acquired using Wi-Fi communication are compared to the Laura data to evaluate the accuracy of the data obtained using the system.

• Journal of the Microelectronics and Packaging Society
• /
• 제31권1호
• /
• pp.1-6
• /
• 2024

Spiders detect even tiny vibrations through their vibrational sensory organs. Leveraging their exceptional vibration sensing abilities, they can detect vibrations caused by prey or predators to plan attacks or perceive threats, utilizing them for survival. This paper introduces a nanoscale crack-based sensor mimicking the spider's sensory organ. Inspired by the slit sensory organ used by spiders to detect vibrations, the sensor with the cracks detects vibrations and pressure with high sensitivity. By controlling the depth of these cracks, they developed a sensor capable of detecting external mechanical signals with remarkable sensitivity. This sensor achieves a gauge factor of 16,000 at 2% strain with an applied tensile stress of 10 N. With high signal-to-noise ratio, it accurately recognizes desired vibrations, as confirmed through various evaluations of external force and biological signals (speech pattern, heart rate, etc.). This underscores the potential of utilizing biomimetic technology for the development of new sensors and their application across diverse industrial fields.

• Korean Journal of Remote Sensing
• /
• 제37권3호
• /
• pp.515-530
• /
• 2021

This study is to estimate soil moisture (SM) using Sentinel-1A/B C-band SAR (synthetic aperture radar) images and Multiple Linear Regression Model(MLRM) in the Yongdam-Dam watershed of South Korea. Both the Sentinel-1A and -1B images (6 days interval and 10 m resolution) were collected for 5 years from 2015 to 2019. The geometric, radiometric, and noise corrections were performed using the SNAP (SentiNel Application Platform) software and converted to backscattering coefficient of VV and VH polarization. The in-situ SM data measured at 6 locations using TDR were used to validate the estimated SM results. The 5 days antecedent precipitation data were also collected to overcome the estimation difficulty for the vegetated area not reaching the ground. The MLRM modeling was performed using yearly data and seasonal data set, and correlation analysis was performed according to the number of the independent variable. The estimated SM was verified with observed SM using the coefficient of determination (R²) and the root mean square error (RMSE). As a result of SM modeling using only BSC in the grass area, R² was 0.13 and RMSE was 4.83%. When 5 days of antecedent precipitation data was used, R² was 0.37 and RMSE was 4.11%. With the use of dry days and seasonal regression equation to reflect the decrease pattern and seasonal variability of SM, the correlation increased significantly with R² of 0.69 and RMSE of 2.88%.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• 제41권3호
• /
• pp.93-100
• /
• 2004

This paper presents a method to integrate the multiple impressions of a finger for improving fingerprint verification performance. Small-sized sensor has advantage that it can be used in many application fields. However, sufficiently large impression of fingerprint is not available due to the small sensing area, and this degrades the verification performance of the system. The proposed method overcomes this problem by combining the information of fingerprints for enrollment. To combine the fingerprints, the alignment process is important first of all. In the proposed algorithm multiple impressions of a finger are coarsely aligned using the corresponding minutiae pairs and then are finely aligned using the Distance Map. We construct an integrated template for enrollment in aligned coordinate system Since this integrated template represents the enlarged finger region, the problem that is occurred by using small sensor can be overcome. Experimental results show that the use of the integrated template of multiple impressions improves the performance of the fingerprint verification system.

• Journal of the Korean Society for Nondestructive Testing
• /
• 제28권5호
• /
• pp.401-406
• /
• 2008

Recently, portable magnetic sensors with high sensitivity are strongly required for various applications such as biosensor, nondestructive testing and directional sensor. A novel magnetic sensor system was developed by utilizing giant magnetoimpedance(MI) effect of soft magnetic ribbons. The sensor system consists of sensing head of $Co_{66}Fe_{4}Si_{15}B_{15}$ ribbon having asymmetric MI characteristics through exchange coupling produced by field-annealing in open air and circuit for signal processing. The sensor system showed almost linear characteristics in dynamic range of $-1\;Oe\;{\sim}\;1\;Oe$ and sensitivity of 10.5 V/Oe. The sensor was applicable to nondestructive testing system to detect defects in wire ropes.

• Proceedings of KOSOMES biannual meeting
• /
• 해양환경안전학회 2006년도 춘계학술발표회
• /
• pp.47-52
• /
• 2006

The cultural grounds of laver has been surveyed using SPOT-5 satellite images to calculate the facilities of laver cultivation area in the coastal waters of Korea 10m resolution multispectral images of SPOT-5 are adopted for the south area of Daebu Island, Hwaseong city to develop an automatic detection approach of laver nets that consists of the following: band difference technique, canny edge detector and morphological analysis. The satellite-based facilities number was relatively high as compared with the licensed number in 2005, 676,749 chaek and 572,745 chaek(柵, unit of measure for laver farm), respectively. The data could be applied to achieve a good harvest for laver seaweed growers and to control its national production keeping a stable market price for the government body.

• Journal of Korea Water Resources Association
• /
• 제36권5호
• /
• pp.839-849
• /
• 2003

Drought is one of the major environmental disasters. Weather data, particularity rainfall, are currently the primary source of information widely used for drought monitoring. However, weather data are often from a very sparse meteorological network, incomplete and/or not always available in good time to enable relatively accurate and timely drought detection. Data from remote sensing platforms can be used to complements weather data in drought. Therefore, data obtained from the Advanced Very High Resolution Radiometer(AVHRR) sensor on board the NOAA polar-orbiting satellites have been studied as a tool for drought monitoring. The normalized difference vegetation index(NDVI)-based vegetation condition index(VCI) were used in this study These indices showed their excellent ability to detect vegetation stress due to drought. The results clearly show that temporal and spatial characteristics of drought in Korea can be detected and mapped by the VCI index.