• Ocean Science Journal
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• v.41 no.2
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• pp.105-111
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• 2006

In this paper, the lines of investigation on a problem of the development of remote acoustic sensing methods in oceanology are formulated. This paper summarizes the results of investigations into the possibilities for monitoring temperature and flow fields in shallow seas. In the discussed experiments, the instrumentation being constituents of the complex for long-duration remote monitoring of marine medium climatic variability and that of the acoustic tomography of shallow sea dynamic processes is used. The acoustic instruments were located on the POI FEB RAS acousto-hydrophysical polygon (Pacific Oceanological Institute, Far Eastern Branch of the Russian Academy of Sciences) near the Gamov Peninsula. Acoustic receiving and transmitting systems operating with multiplex phase-manipulated signals (of M-codes) at frequency range 250-2500 Hz form the basis for this complex.

• Korean Journal of Remote Sensing
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• v.24 no.5
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• pp.445-452
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• 2008

Preliminary results are reported on ship detection using coherence images computed from cross-correlating images of multi-look-processed dual-polarization data (HH and HV) of ENVISAT ASAR. The traditional techniques of ship detection by radars such as CFAR (Constant False Alarm Rate) rely on the amplitude data, and therefore the detection tends to become difficult when the amplitudes of ships images are at similar level as the mean amplitude of surrounding sea clutter. The proposed method utilizes the property that the multi-look images of ships are correlated with each other. Because the inter-look images of sea surface are covered by uncorrelated speckle, cross-correlation of multi-look images yields the different degrees of coherence between the images and water. In this paper, the polarimetric information of ships, land and intertidal zone are first compared based on the cross-correlation between HH and HV images, In the next step, we examine the technique when the dual-polarization data are split into two multi-look images, It was shown that the inter-look cross-correlation method could be applicable in the performance improvement of small ship detection and the land masking, It was also found that a simple combination of coherence images from each co-polarised (HH) inter-look and cross-polarised (HV) inter-look data can provide much higher target-detection possibilities.

• Korean Journal of Remote Sensing
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• v.21 no.5
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• pp.405-415
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• 2005

It is difficult to classify tidal flat surface that is composed of a mixture of mud, sand, water and microphytobenthos. We used a Linear Spectral Unmixing (LSU) method for effectively classifying the tidal flat surface characteristics within a pixel. This study aims at 1) detecting algal mat using LSU in the Saemangeum tidal flats, 2) determining a suitable end-member selection method in tidal flats, and 3) find out a habitual characteristics of algal mat. Two types of end-member were built; one is a reference end-member derived from field spectrometer measurements and the other image end-member. A field spectrometer was used to measure spectral reflectance, and a spectral library was accomplished by shape difference of spectra, r.m.s. difference of spectra, continuum removal and Mann-Whitney U-test. Reference end-members were extracted from the spectral library. Image end-members were obtained by applying Principle Component Analysis (PCA) to an image. The LSU method was effective to detect microphytobenthos, and successfully classified the intertidal zone into algal mat, sediment, and water body components. The reference end-member was slightly more effective than the image end-member for the classification. Fine grained upper tidal flat is generally considered as a rich habitat for algal mat. We also identified unusual microphytobenthos that inhabited coarse grained lower tidal flats.

• Korean Journal of Remote Sensing
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• v.20 no.1
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• pp.57-64
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• 2004

In GIS-based network analysis, topological measure of network structure can be considered as one of important factors in the urban transportation analysis. Related to this measure, it is known that the connectivity indices such as alpha index and gamma index, which mean degree of network connectivity and complexity on a graph or a circuit, provide fundamental information. On the other hand, shimbel index is one of GIS-based spatial metrics to characterize degree of network concentration. However, the approach using these quantitative indices has not been widely used in practical level yet. In this study, an application program, in complied as extension, running on ArcView- GIS is implemented and demonstrated case examples using basic layers such as road centerline and administrative boundary. In this approach, geo-spatial imagery can be effectively used to actual applications to determine the analysis zone, which is composed of networks to extract these indices. As the results of the implementation and the case examples, it is notified that alpha and gamma indices as well as shimbel index can be used as referential data or auxiliary information for urban planning and transportation planning.

• Journal of Advanced Navigation Technology
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• v.2 no.2
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• pp.126-131
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• 1998

In optical scanning holography, 3-D holographic information of an object is generated by 2-D active optical scanning. The optical scanning beam can be a time-dependent Gaussian apodized Fresnel zone plate. In this technique, the holographic information manifests itself as an electrical signal which can be sent to an electron-beam-addressed spatial light modulator for coherent image reconstruction. This technique can be applied to 3-D optical remote sensing especially for identifying flying objects. In this paper, we first briefly review optical scanning holography and analyze the resolution achievable with the system. We then present mathematical expression of real and virtual image which are responsible for holographic image reconstruction by using Gaussian beam profile.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1917-1921
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• 2008

Ultraviolet-nanoimprint lithography (UV-NIL) is promising technology for cost effectively defining micro/nano scale structure at room temperature and low pressure. In addition, this technology is fascinating because of it's possibility for high-throughput patterning without complex processes. However, to acquire good micro/nano patterns using this technology, there are some challenges such as uniformity and fidelity of patterns, etc. In this paper, we have focused on uniform contact mechanism and performed contact mechanics analysis. The dimension of the flexible sheet to get adequate uniform contact area has been obtained from contact mechanics simulation. Based on this analysis, we have made a uniform pressurizing device and confirmed its uniform pressurized zone using a pressure sensing paper.

• Journal of the Korean Association of Geographic Information Studies
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• v.6 no.3
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• pp.117-128
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• 2003

The purpose of this study is to analyze the characteristics of the landscape type on Chunchon by CG(computer graphics) pictures and visibility analysis. The land use CG picture and the land cover CG picture are created by using Zoning area data and DEM(digital elevation model), and by using data of land cover classification and DEM. According to the analysis result of the land cover from 1989 to 2000, the city area has increased to $7.7km^2$, the green area has diminished to $12.7km^2$. The tendency of the city area increases and the green area decreases which appear in the city area, developmental restriction zone and green area on land use. The landscape is classified into three types by cluster analysis using the area rate of the element which constitutes the land use CG picture. Type 1 is a landscape characteristics of developmental restriction zone. Type 2 is a landscape characteristics of green land and type 3 is a landscape characteristics based on city area and water area. The increase of city area and decrease of green area are shown in all landscape types of land cover CG pictures. The same tendency is seen in the place where the scenery is of high importance as a result of visible analysis. The preservation and management of the scenery to the green area are requird in developmental restriction zone are required.

• Korean Journal of Remote Sensing
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• v.28 no.2
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• pp.203-214
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• 2012

The physical environment of urban areas covered mostly by concrete and asphalt is the main cause of the urban heat island effect, primarily becoming apparent through increased land surface temperature. This study examined the effect of different urban land cover types on the land surface temperature using MODIS, Landsat ETM+ and RapidEye satellite data. As a result, the remote sensing based land surface temperature showed a marked difference according to the land use pattern in the case study of Ilsan new city. The high-rise apartment residential districts with less building-to-land ratio and higher green area ratio revealed lower land surface temperature than the low-story single-family housing districts characterized by relatively high building-to-land ratio and low green area ratio. From the view of climate zone and land cover types, there is a strong linear correlation between the impervious land cover ratio and the land surface temperature; the land surface temperature increases as the impervious built-up areas expand. In contrast, vegetation;water and shadow areas affect the decrease of land surface temperature. There is also a negative (-) correlation between NDVI and land surface temperature but the seasonal variation of NDVI can be hardly corrected.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.1B
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• pp.8-15
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• 2008

Cognitive radio technology enables to share the spectrum dedicated to primary users. In CR network, it is of primary concern to protect the primary users. Thus, it is required to periodically sense the spectrums occupied by primary users and adapt the communication parameters used by CR users to protect the primary users. However, it is inevitable to experience the hidden node problem due to the primary users, that are not detected by spectrum sensing. To perfectly protect the primary users, it is essential to address the hidden node problem in CR network. In this paper, we propose a new approach to handle the hidden node problem and evaluate the performance of proposed scheme.

• Korean Journal of Remote Sensing
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• v.35 no.6_1
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• pp.987-997
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• 2019

Recently the demand for drones is rapidly increasing, as developing Unmanned Aerial Vehicle (UAV) and growing interest in them. Compared to traditional satellite and aerial imagery, it can be used for various researches (environment, geographic information, ocean observation, and remote sensing) because it can be managed with low operating costs and effective data acquisition. However, there is a disadvantage in that only a small area is acquired compared to the satellite and an aircraft, which is a traditional remote sensing method, depending on the battery capacity of the UAV, and the distance limit between Ground Control System (GCS) and UAV. If remote control at long range is possible, the possibility of using UAV in the field of remote sensing can be increased. Therefore, there is a need for a communication network system capable of controlling regardless of the distance between the UAV and the GCS. The distance between UAV and GCS can be transmitted and received using simple radio devices (RF 2.4 GHz, 915 MHz, 433 MHz), which is limited to around 2 km. If the UAV can be managed simultaneously by improving the operating environment of the UAV using a Long-Term Evolution (LTE) communication network, it can make greater effects by converging with the existing industries. In this study, we performed the maximum straight-line distance 6.1 km, the test area 2.2 ㎢, and the total flight distance 41.75 km based on GCS through LTE communication. In addition, we analyzed the possibility of disconnected communication through the base station of LTE communication.