• Journal of Advanced Navigation Technology
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• v.24 no.6
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• pp.587-592
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• 2020

The giant information exchange enabled by the Internet of Things paradigm will likely exploit electrical lines as a ready-to-use infrastructure. The advantage of using the pre-installed infrastructure of wiring networks makes power line communication a competitive technology for broad-band communications. Therefore, there has been a growing interest towards the use of existing power line communication channels as an effective means for transmitting high speed data and Internet service. One of the main noise types affecting power line communication systems is the impulsive noise, and the focus of this work is on the impact of this impulsive noise on the performance of OFDM-QPSK systems. For the performance analysis of impulsive noise, data measured in three environments were used. Through the analysis, it is shown that OFDM-QPSK system outperforms QPSK system for most of the impulsive noise cases. Also, RS-coded OFDM-QPSK system can achieve good BER performance under 3 cases impulsive noise environment.

• Journal of The Korean Astronomical Society
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• v.49 no.3
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• pp.65-71
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• 2016

We obtain the first complete CCD light curves (LCs) of the contact binary AP UMi in the VRI bands and analyzed them by means of the PHOEBE code. A spotted model is applied to treat the asymmetry in the LCs. The LC morphology clearly shows the O'Connell effect and the solution shows an influence of star spots on both components. Such effect of star spots is common between the RS CVn and W UMa chromospherically active stars. Based on the obtained solution of the LCs we investigate the evolutionary state of the components and conclude that the system is a pre-intermediate contact binary (f = 0.29) with mass ratio q = 0.38, and it is an A-type W UMa system where the less massive secondary component is cooler than the more massive primary one.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04b
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• pp.433-438
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• 1998

Design lateral strength calculated by current seismic design code is prescribed to be much lower than the force level required for a structure to respond elastically during design level earthquake ground motion. Present procedures for calculating seismic design forces are based on the use of elastic spectra reduced by a strength reduction factor known as "response modification factor, R". This factor accounts for the inherent ductility, overstrength, redundancy, and damping of a structural system. This study considers ductility and overstrength of the wall-type structure for investigating R factor. This means that R factor is determined from the product of "ductility-based R factor($R_$\mu$$) and overstrength factor($R_s$). $R_$\mu$$ factor is calibrated to attain the targer ductility ratio (system ductility capacity) and produced in the from of $R_$\mu$$ spectra considering the influence of target ductility, natural period, and hysteretic model. On the other hand, $R_s$ is more difficult to quantify, since it depends on both material and system-dependent uncertain parameters. In this study Rs factor was determined from the result of push-over analysis.-over analysis.

• Journal of the Korean Society of Physical Medicine
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• v.6 no.4
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• pp.391-396
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• 2011

Purpose : The Purpose of this study is to investigate the values of foot pressure during gait cycle according to adaptation and sudden remove of various color information. Methods : Participants who met the criteria for this study (n=13). RS-Scan was used to measure plantar foot pressur according to Five kinds of color information in this study. Results : The adaptation of various color information is no statistically significant on all area. But sudden remove of various color information is statistically significant on T2-5, M5 and MF area. Conclusion : The results of this study suggest that sudden remove of various color information reduces the ability of balance during gait in normal adults. And these results means that increase risk of falling down according to sudden remove of various color information.

• Journal of environmental and Sanitary engineering
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• v.21 no.4 s.62
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• pp.61-76
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• 2006

A Line Density algorithm was developed to quantify the sea surface temperature distribution using NOAA Sea Surface Temperature(SST) data and Geographic Information Systems(GIS), In addition, a GIS based automation model was designed to extract the Line Density Indices were determined by applying K-means Cluster. SST data in terms of March to May obtained on the coastal area of the Uljin from 2001 to 2004 in spring were used to make two data sets of average sea water temperature map in terms of year as well as month. From the result it was formed that water temperature gradient in April was the strongest among the other months, In particular very strog formation of oceanic front as well as temperature gradients were observed in front of the coastal area around Wonduk and Jukbyeon countries. Because those coastal area is a confront zone of two cold and a warm. It is expected that the development of a Line Density Algorithm would contribute to quantify of the SST for the research of Sea Surface Front(SSF) related to marine life management and the sea environmental conservation.

• Korean Journal of Computational Design and Engineering
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• v.4 no.4
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• pp.339-349
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• 1999

The punose of this paper is to introduce the comprehensive CAM system (called PosCAM) supporting various function requested from shop floor operators. PosCAM is comported of two subsystems (PosCAM I and PosCAM II) which are designed to make up for the contemporary CAD/CAM systems. PosCAM I is mainly for : a) verifying the part programs written in both custom macros and standard G-codes, b) enhancing machining productivity and quality with built-in cutting conditions and feedrate optimization algorithm. PosCAM II is for : a) efficiently managing the numerous part programs and tool data stored in CNC memory, and b) integratively controlling and monitoring various CNCs from the control center through RS-422 with DNC 2 protocol. The developed systems have been tested via various experiments, and can be Applied for the industrial CNC machine shop as a means for enhancing productivity. The PosCAM system has been implemented and successfully used in the Machine Shop Department of PosCAM since march 1998.

• Journal of Korean Society for Geospatial Information Science
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• v.23 no.3
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• pp.85-93
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• 2015

This paper mainly introduces the methods of extracting landslide information using ALOS(Advanced Land Observing Satellite) images and GIS(Geographical Information System) technology. In this study, we classified images using three different methods which are the unsupervised the supervised and the PCA(Principal Components Analysis) for extracting landslide information based on characteristics of ALOS image. From the image classification results, we found out that the quality of classified image extracted with PCA supervised method was superior than the other images extracted with the other methods. But the accuracy of landslide information extracted from this image classification was still very low as the pixels were very similar between the landslide and safety regions. It means that it is really difficult to distinguish those areas with an image classification method alone because the values of pixels between the landslide and other areas were similar, particularly in a region where the landslide and other areas coexist. To solve this problem, we used the LSM(Landslide Susceptibility Map) created with ArcView software through weighted overlay GIS method in the areas. Finally, the developed LSM was applied to the image classification process using the ALOS images. The accuracy of the extracted landslide information was improved after adopting the PCA and LSM methods. Finally, we found that the landslide region in the study area can be calculated and the accuracy can also be improved with the LSM and PCA image classification methods using GIS tools.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.10
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• pp.2227-2234
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• 2009

DVB-SSP is a new broadcasting system for hybrid satellite communications, which supports mobile handheld systems and fixed terrestrial systems. An upper layer, including erasure Reed-Solomon error correction combined with cyclic redundancy check. However, a critical factor must be considered in upper layer decoding. If there is only one bit error in an IP packet, the entire IP packet is considered as unreliable bytes, even if it contains correct bytes. If, for example, there is one real byte error, in an IP packet of 512 bytes, 511 correct bytes are erased from the frame. Therefore, this paper proposed upper layer decoding methods; LLR-based decoding. By means of simulation we show that the performance of the proposed decoding algorithm is superior to that of the conventional one.

• Korean Journal of Remote Sensing
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• v.33 no.5_3
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• pp.835-854
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• 2017

Government regulations and policies are important means of restraining the indiscreet expansion of urban areas. According to the standards from those means, it is clear that the fluctuation of forest green proportion encroached by the increase of urban space is obvious. In this study, we interpreted the changes of urban areas as well as the green ones owing to the urban expansion by the decades from 1996, with focusing on the cities of Seoul and Daegu highly developed in South Korea. The purpose of this study is to analyze the spatial expansion and morphological characteristics of urban land cover using not only satellite imageries (1996, 2006, 2016). but also the urban expansion intensity index (UEII) and GUIDOS program. Ultimately, this study is to compare the changes in the rate of forests due to urban expansions annually analyzed based on areas of forest elevation, slope, and the area of single forest patch. In Seoul, the expansion begun from urban space to suburban areas was comparatively rapid, which led the forest fragmentation and the gradual decline of the single patch. However, when it comes to DEM (Digital elevation model) and slope above a certain standard, by the development regulations, there was little decrease in area by anthropogenic developments. The city of Daegu has increased at a slow speed since 1996 in urban and suburban areas, whereas green forests have greatly increased through green forest conservation campaigns. In this way, as to the government policies and regulations, the quantitative and morphological expansion of cities owing to development could be controlled and forest spaces could be preserved as well. Therefore, regulations and policies by the government should be appropriately utilized for sustainable cities.

• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.1
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• pp.118-129
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• 2011

This Study has developed the information system of the rivers based on 3D image GIS by converging the latest information technology of GIS(Geographic Information System), RS(Remote Sensing), GNSS(Global Navigation Satellite System), aerial laser survey(LiDAR) with real time network technology in order to understand the current situation of all the four major rivers and support the administrative management system. The said information system acquires the high resolution aerial photographs of 25cm, aerial laser survey and water depth surveying data to express precise space information on the whole Youngsan River which is the leading project site out of the four river sites. Monitoring the site is made available on the transporting means such as a helicopter, boat or a bus in connection with locational coordinate tracking skill for the moving objects in real time using GNSS. It makes monitoring all the information on the four river job sites available at a glance, which can obtain the reliability of the people to such vast areas along with enhancing the recognition of the people by publicity of four Rivers Revitalizing Project and reports thereof.