• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.10 no.5
• /
• pp.786-795
• /
• 1999

To detect the precise of arrival of target signal in real ocean environments, Inverse beamformnig(IBF) solutions to the Inverse beamforming integral equation are surveyed theoretically and the performance properties of the IBF are analyzed with simulations. IBF-Cardioid beamforming algorithm is proposed for port/starboard discrimination and the performance gains are studied with simulations. It is shown that IBF has a 3 dB array noise gain advantage over CBF under ideal conditions. This 3 dB array noise gain advantage is proven by theocratical studies and simulations. This array noise gain advantage leads to a minimum detectable level advantage for IBF output compared with CBF output. The fact that the IBF beamwidth is narrower than the CBF beamwidth by a factor of 0.68 proves the performance of detection and spatial resolution improvement. Comparing the simulation results of IBF-Cardioid beamforming and Conventional Cardioid beamforming, it is shown that IBF-Cardioid beamformer have performance enhancement in minimum detection level, detection accuracy and resolution.

• The Journal of the Acoustical Society of Korea
• /
• v.21 no.5
• /
• pp.478-484
• /
• 2002

Linear towed arrays (LTA) have a nonlinear shape due to tow vessel motion, ocean swells and currents. By reasons of nominally linear shape, various towed array shape estimation techniques have been developed since the perturbed shape cause the error in target detection. In this paper,, we propose the beamforming method for the perturbed LTA with simple structure. The proposed method linearizes a nonlinear phase of steering vector with position information measured by two reference sensors. It can be proved using some properties of Markov transition matrix, and iteration number of linearization process is decided by variance of cross phase difference. As a result of computer simulation in the ocean environment, beampattern of the proposed method is almost same with the ideal case in my type of array shape. In the signal-to-noise ratio (SNR) performance simlation, the DOA estimation performance of the proposed beamforming method is evaluated, and the comparison with Bartlett beamformer of the LTA shows that the proposed method can estimate. the spatial characteristic of sources more accuracy.

• Journal of Cadastre & Land InformatiX
• /
• v.45 no.1
• /
• pp.137-150
• /
• 2015

The methodology on digital cadastre(World Geodetic System Conversion) needs to be specified because the primary target site is discussed for large national estate such as road, river etc. on nationwide. Comprehensively reviews on similar cases and literature reviews to make a methodology for digital cadastre on large national estate, cadastral map revision is required before converting to World Geodetic System. The revisions are on subdivision survey or the other surveys to the necessary area through inspection of geometry and attributes. And the researcher pointed out the need of registration conversion and union of parcel to remove small parcel or to remove the inconsistency of land use type. Basically a systematic maintenance of cadastral map is necessary because the World Geodetic System Conversion unresolved the poor cadastral map quality to digital cadastre on large national estate.

• Journal of Korean Society for Geospatial Information Science
• /
• v.23 no.3
• /
• pp.3-10
• /
• 2015

All kinds of objects on the ground have inherent spectral reflectance curves, which can be used to classify the ground objects and to detect the target. Remotely sensed data have to be transferred to spectral reflectance for accurate analysis. There are formula methods provided by the institution, mathematical model method and ground-data-based method. In this study, RapidEye satellite image was converted to reflectance data using spectral reflectance of a CASI hyperspectral image by using vicarious radiometric calibration. The results were compared with those of the other calibration methods and ground data. The proposed method was closer to the ground data than ATCOR and New Kurucz 2005 method and equal with ELM method.

• Journal of Korean Society for Geospatial Information Science
• /
• v.22 no.1
• /
• pp.55-62
• /
• 2014

Diverse improvement projects such as replacing street lamps with LED, street trees, etc are currently in progress in Korea to reduce greenhouse gas so as to cope with change in climate. However, the effect of climate change policy is not exactly analyzed, because exhaust quantity and absorption quantity of greenhouse gas of the target street lamp and street trees are not arranged as information. Thus, this study studied the method to systematically manage low carbon related information of urban facilities by using GIS. It was found that low carbon information of the urban facilities is necessary to exactly analyze effect of climate change policy and the method to calculate carbon exhaust quantity and absorption quantity of each facilities should be established to build exact low carbon information of urban facilities. Further, it was found that the visualization of information related to low carbon of street lamp and street trees by using GIS easily and visually grasps and systematically controls the effect of policy coping with change in climate than the existing numeral data of exhaust quantity and absorption quantity of greenhouse gas.

• Journal of Korean Society for Geospatial Information Science
• /
• v.24 no.3
• /
• pp.85-92
• /
• 2016

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.

• Bulletin of the Korean Space Science Society
• /
• 2009.10a
• /
• pp.35.3-36
• /
• 2009

To investigate properties of the stellar contents of the resolved asymptotic giant branch stars in the nearby dwarf galaxies, we obtained wide-field JHKs images of the dwarf irregular galaxies NGC 6822, IC 1613 and the dwarf elliptical galaxy NGC 205, using the WIRCam near-infrared imager of the CFHT. The obtained (J-Ks, Ks) and (H-Ks, Ks) color-magnitude diagrams for the resolved stars in the galaxies contain populations of foreground stars, super giant stars, red giant stars and the asymptotic giant branch (AGB) stars. Using corollary photometric data in the visible bands, AGB stars were selected in the color-magnitude diagrams with a wide wavelength baseline in color indices. In color-color diagrams of the resolved AGB stars, we identified C stars from M giant stars for each galaxies, i.e., 726 C stars in NGC 6822, 126 C stars in IC 1613 and 593 C stars in NGC 205. The number ratios of C stars to M-giants were estimated to be $0.59\pm0.03$ in NGC 6822, $0.30\pm0.03$ in IC 1613 and $0.14\pm0.01$ in NGC 205. From analyses of the correlations of the spatial distribution of the C/M ratios with the HI properties and dynamical structures of the target galaxies, we discuss environmental effects of the star formation in the galaxies. We also discuss the epochs of the AGB star formation in the galaxies by comparing theoretical isochrones with the color distributions and luminosity functions of the AGB stars.

• Journal of Korean Society for Geospatial Information Science
• /
• v.14 no.3 s.37
• /
• pp.3-11
• /
• 2006

The need for edge detection about topography data from the high resolution satellite imagery is happening with increasing frequency according to many people utilize the its imagery as various fields recently. Many experts is recognizing of other GIS will make use of the road detection from the high resolution satellite imagery, including ITS (Intelligent Transportation Systems) and urban planning. This paper is comparative analysis of LPF (Low Pass Filtering) and HPF (High Pass Filtering) for roads edge detection from high resolution satellite imagery. As a result, LPF and HPF can be highlight selective pixels at edge area about input data. In case or applying to other techniques such as LPF for the same purpose, they aye more effective for wide road width which often cause the slight distortion of boundary or overall change of brightness values on the whole Image. Whereas, HPF has ability to enhance selectively detailed components in a target image.

• Journal of Korea Water Resources Association
• /
• v.46 no.6
• /
• pp.683-696
• /
• 2013

Recent inundation damage has frequently occurred due to heavy rainfall in urban area, because rainfall has locally occurred exceeding the capability of a flood control plan by the exiting design rainfall from the data of Seoul weather station. Accordingly the objective of this study is to predict new design rainfall in order to make a future flood control plan considering climate change. In this study, for considering spatial characteristics of rainfall in urban area, data of AWS was used and for retaining insufficient rainfall data, WGR model was estimated the application of target area. The results were compared with the observation data and consequently show reasonable results. In addition, to prepare for climate change, design rainfall was calculated by applying for various climate scenarios and the result would be used in order to establish future flood control plan.

• International Journal of Knowledge Content Development & Technology
• /
• v.1 no.1
• /
• pp.61-79
• /
• 2011

This study purposed to discover whether or not academic libraries reflect these changing roles. We selected K University as the research target and surveyed user satisfaction of materials, staff services, facilities, electronic devices, media, and so on. The research findings are as follows: 1) the frequency of library visits of University K was on the high side, 2) the primary purpose of using the academic library was associated with learning or reading, therefore, the most used library spaces were related to that, 3) the most used library materials were 'general books', the most unused were 'reference books', 4) the most preferred way to obtain needed materials when failing to find wanted materials was 'Contact librarian'. A similar phenomenon occurred in terms of facility use, 5) university K's users were usually satisfied with the loan policy, 6) the rate of users who don't know whether there is user education was very high, the rate of users who have no experience with user education was extremely low. These research findings can be referenced by library management to improve libraries' service quality and take advantage of complex spatial configurations.