• Korean Journal of Remote Sensing
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• v.20 no.5
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• pp.289-305
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• 2004

Atmospheric correction of Landsat Visible and Near Infrared imagery (VIS/NIR) over aquatic environment is more demanding than over land because the signal from the water column is small and it carries immense information about biogeochemical variables in the ocean. This paper introduces two methods, a modified dark-pixel substraction technique (path--extraction) and our spectral shape matching method (SSMM), for the correction of the atmospheric effects in the Landsat VIS/NIR imagery in relation to the retrieval of meaningful information about the ocean color, especially from Case-2 waters (Morel and Prieur, 1977) around Korean peninsula. The results of these methods are compared with the classical atmospheric correction approaches based on the 6S radiative transfer model and standard SeaWiFS atmospheric algorithm. The atmospheric correction scheme using 6S radiative transfer code assumes a standard atmosphere with constant aerosol loading and a uniform, Lambertian surface, while the path-extraction assumes that the total radiance (L/sub TOA/) of a pixel of the black ocean (referred by Antoine and Morel, 1999) in a given image is considered as the path signal, which remains constant over, at least, the sub scene of Landsat VIS/NIR imagery. The assumption of SSMM is nearly similar, but it extracts the path signal from the L/sub TOA/ by matching-up the in-situ data of water-leaving radiance, for typical clear and turbid waters, and extrapolate it to be the spatially homogeneous contribution of the scattered signal after complex interaction of light with atmospheric aerosols and Raleigh particles, and direct reflection of light on the sea surface. The overall shape and magnitude of radiance or reflectance spectra of the atmospherically corrected Landsat VIS/NIR imagery by SSMM appears to have good agreement with the in-situ spectra collected for clear and turbid waters, while path-extraction over turbid waters though often reproduces in-situ spectra, but yields significant errors for clear waters due to the invalid assumption of zero water-leaving radiance for the black ocean pixels. Because of the standard atmosphere with constant aerosols and models adopted in 6S radiative transfer code, a large error is possible between the retrieved and in-situ spectra. The efficiency of spectral shape matching has also been explored, using SeaWiFS imagery for turbid waters and compared with that of the standard SeaWiFS atmospheric correction algorithm, which falls in highly turbid waters, due to the assumption that values of water-leaving radiance in the two NIR bands are negligible to enable retrieval of aerosol reflectance in the correction of ocean color imagery. Validation suggests that accurate the retrieval of water-leaving radiance is not feasible with the invalid assumption of the classical algorithms, but is feasible with SSMM.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.7
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• pp.1621-1630
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• 2009

There is a lot of recent research to provide services of dynamic distributed contents in P2P-based distributed environment. Distributed services of contents objects, however, have problems in QoS and dynamic management of segments. This paper proposed a new segment management method for the service of P2P-based distributed contents. The proposed method manages groups by the SGM(Segment Group Manager). The SGM manages streaming efficiently by the grouping of segments to be served in P2P environment. The segments in the same group cooperate for improved QoS using the management structure based on the distance and relationship. The distance-based management structure is for the improvement of retrieval efficiency while the relationship-based management structure is for the improvement of service ratio. The simulation results of the proposed method showed improvements in average transmission efficiency and average service rate. The improvement is 8% - 30% in average transmission efficiency and 10% - 30% in average service rate.

• Journal of Soil and Groundwater Environment
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• v.18 no.5
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• pp.46-55
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• 2013

The main objective was to evaluate the efficiencies of different separation techniques, such as gravity separation, magnetic separation, and aerial separation. Zinc and cadmium removal efficiencies by gravity separation and magnetic separation were 28.3~29.3% and 19.1%, respectively, and were higher than the efficiency obtained by aerial separation. Results showed that the combination of gravity separation and magnetic separation in series which was to maximize the removal efficiencies gave removal efficiency of 21.5~38.7% for zinc and 22.1~23.4% for cadmium. The mass of soil meeting the regulation standards for zinc and cadmium after retrieval from the combined separation process accounted for approximately 80% of the treated soil that would be reusable without the pre-treatment procedure as the neutralization process using in the soil washing method. Physical separation techniques utilizing heavy metal properties are the alternative method to remediate heavy-metal contaminated soils in environmental and economic aspects.

• Cartoon and Animation Studies
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• s.49
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• pp.1-23
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• 2017

3D animation production has had a pivotal position in current animation industry and the necessity of professional management tool for 3D animation production has claimed due to its sophisticated pipeline from advance of technology and global production partnership trend. Shotgun and Ftrack are providing the most appropriate management toolset for 3D animation management among the extant management tools and the efficiency of Shotgun & Ftrack is identified compared with the traditional document oriented management style. The biggest strength of production management using Shotgun is that all of the production staff can directly participate in the communication on the tools therefore they can share the information on Shotgun & Ftrack in real time without constraint of time and location. Moreover, all the process of the production and the history of the discussion on certain production issues are systematically accrue on the tool so that the production history can be easily tracked. Finally, the production management using tools contributes collecting and analysing the production information for the production management team in studios. However, Shotgun & Ftrack has metadata based retrieval method which cost huge amount of effort by human's manual annotation and it also has the limitation of accuracy. In addition, the fact that studios has to have technical professionals first in order to institute the tools into their studios is the actual difficulty of Korean studios when they want to use management tools for their project. Thus, this paper suggests adopting the content-based retrieval system on the tools and tools' expanded technical service for the studios as the solution of the identified issues.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.596-607
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• 2017

This study examined the method for adding related to "stomach neoplasms" as filters to the Medical Subject Headings (MeSH) for search as well as a method for improving the search efficiency through a word-proximity search by measuring the distance of co-occurring terms. A total of 8,625 articles published between 2007 and 2016 with the major topic terms "stomach neoplasms" were downloaded from PubMed article titles. The vocabulary to be added to the MeSH for search were analyzed. The search efficiency was verified by 277 articles that had "Stomach Neoplasms" indexed as MEDLINE MeSH in KoreaMed. As a result, 973 terms were selected as the candidate vocabulary. "Gastric Cancer" (2,780 appearances) was the most frequent term and 7,376 compound words (88.51%) combined the histological terms of "stomach" and "neoplasm", such as "gastric adenocarcinoma" and "gastric MALT lymphoma". A total of 5,234 compounds words (70.95%), in which the co-occurring distance was two words, were found. The matching rate through the MEDLINE MeSH and KoreaMed MeSH Indexer was 209 articles (75.5%). The search efficiency improved to 263 articles (94.9%) when the search filters were added, and to 268 articles (96.7%) when the 13 word-proximity search technique of the co-occurring terms was applied. This study showed that the use of a thesaurus as a means of improving the search efficiency in a natural language search could maintain the advantages of controlled vocabulary. The search accuracy can be improved using the word-proximity search instead of a Boolean search.

• Journal of the Korean Society for information Management
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• v.18 no.1
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• pp.65-84
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• 2001

The purpose of this study was to design and evaluate a metadata system for internet-based syllabi in computer science. The study constructed two prototype systems for the experiment. One was constructed using only Dubline Core (DC) elements and the other was a DC-expanded system with additional eight elements that are not the part of DC elements. The thlrty subjects were chosen from those who majored in Computer Science. Two retrieval tasks were assigned to them. One was to find syllabi in which they are' interested and the other was to find relevant course syllabi for a given course title. After the search, they were asked to evaluate the systems in terms of efficiency, accuracy, and their satisfaction of the system. The result of the first experiment indicates that DC-based system performed significantly better in terms of search time and DC-expanded system in terms of satisfaction measure. An additional experiment was conducted to test efficiency of the browsing categories. The interview with subjects was carried out to find any difficulties associated with the current browsing scheme. The subjects expressed much1 satisfaction about assigning a course to multiple browsing categories.

• Journal of Intelligence and Information Systems
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• v.12 no.3
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• pp.33-46
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• 2006

In order to decrease the number of handles, speed up retrieval operations, and manage products efficiently, the investment of facilities such as the installation of the storage equipment and the enlargement of the storage area may be attempted. However, the same objectives can be accomplished by utilizing the existing storage area efficiently. In many types of storage facilities, because of the limitation of storage areas, products are usually piled up, which may cause rehandles of inventories. Rehandles influence significantly the handling efficiency of warehouses. This study develops methods for minimizing rehandles of inventories to improve the operational efficiency of warehouses. A mixed storage problem is addressed for minimizing the expected number of rehandles. Optimization models are proposed and the genetic algorithm is applied to solve the problem.

• Korean Journal of Remote Sensing
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• v.35 no.1
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• pp.29-37
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• 2019

Synthetic Aperture Radar (SAR) observations are powerful tools to monitor surface's displacement very accurately, induced by earthquake, volcano, ground subsidence, glacier movement, etc. Especially, radar interferometry (InSAR) which utilizes phase information related to distance from sensor to target, can generate displacement map in line-of-sight direction with accuracy of a few cm or mm. Due to decorrelation effect, however, degradation of coherence in the InSAR application often prohibit from construction of differential interferogram. Offset tracking method is an alternative approach to make a two-dimensional displacement map using intensity information instead of the phase. However, there is limitation in that the offset tracking requires very intensive computation power and time. In this paper, efficiency of parallel computing has been investigated using high performance computer for estimation of glacier velocity. Two TanDEM-X SAR observations which were acquired on September 15, 2013 and September 26, 2013 over the Narsap Sermia in Southwestern Greenland were collected. Atotal of 56 of 2.4 GHz Intel Xeon processors(28 physical processors with hyperthreading) by operating with linux environment were utilized. The Gamma software was used for application of offset tracking by adjustment of the number of processors for the OpenMP parallel computing. The processing times of the offset tracking at the 256 by 256 pixels of window patch size at single and 56 cores are; 26,344 sec and 2,055 sec, respectively. It is impressive that the processing time could be reduced significantly about thirteen times (12.81) at the 56 cores usage. However, the parallel computing using all the processors prevent other background operations or functions. Except the offset tracking processing, optimum number of processors need to be evaluated for computing efficiency.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2021.11a
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• pp.101-103
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• 2021

With the rapid increase in the quantity of goods transported worldwide, companies are now started to show great interest in unmanned automated warehouses along with related research and development due to the increase of warehouse efficiency and reduction warehouse manpower. In a number of small warehouses, shuttle rack-based layouts that can handle inventory flow flexibly. However, the shuttle rack-based logistics center does not operate in case of emergency situations (faults, power outages, etc.), which seriously affects the efficiency and inventory management of the entire logistics center. Accordingly, in shuttle rack-based logistics center, we have classified various shuttle passages and RTV passages by layout and have analyzed its characteristics and types, along with derived reliability for each layout. The loading rate was also derived differently according to the number of passages, and have compared and analyzed reliability and loading rate for each layout.

• Journal of Digital Contents Society
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• v.8 no.2
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• pp.113-119
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• 2007

Recently, multimedia applications using internet are increasing by emergency of UCC. The retrieval of photo, video, audio is a main issue to increase utility of access and efficiency of access time. But the exist multimedia applications do not provide the practical ranking system. They provide only simple ranking system using metric. This paper provides "PhotoToc", the user favor-based multimedia ranking system, that can provide differenced view to users. The proposed system has a to retrieve the user centered results.