• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.6
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• pp.1293-1300
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• 2012

With the rapid evolution of mobile devices and the development of wireless networks, users of mobile social network service on smartphone have been increasing. Also the security of personal information as a result of real-time communication and information-sharing are becoming a serious social issue. In this paper, a framework that can be linked with a social network services platform is designed using OpenAPI. In addition, we propose an authentication and detection mechanism to enhance the level of personal information security. The authentication scheme is based on an user ID and password, while the detection scheme analyzes user-designated input patterns to verify in advance whether personal information protection guidelines are met, enhancing the level of personal information security in a social network service environment. The effectiveness and validity of this study were confirmed through performance evaluations at the end.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.2
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• pp.308-313
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• 2021

In this study, tweets about the 2019 Koreas-US DMZ Summit were collected along with a time sequence and analyzed by a sequential topic modeling method, Dynamic Topic Modeling(DTM). In microblogging services such as Twitter, unstructured data that mixes news and an opinion about a single event occurs at the same time on a large scale, and information and reactions are produced in the same message format. Therefore, to grasp a topic trend, the contextual meaning can be found only by performing pattern analysis reflecting the characteristics of sequential data. As a result of calculating the DTM after obtaining the topic coherence score and evaluating the Latent Dirichlet Allocation(LDA), 30 topics related to news reports and opinions were derived, and the probability of occurrence of each topic and keywords were dynamically evolving. In conclusion, the study found that DTM is a suitable model for analyzing the trend of integrated topics in a specific event over time.

• Korean Journal of Ichthyology
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• v.33 no.4
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• pp.205-216
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• 2021

Phylogenetic reconstruction based on one locus or a few loci can be misleading due to gene-tree/species-tree discordance. Species delimitation and intraspecific studies also often suffered from low resolution because of insufficient statistic power when few loci were used. Exon capture method is one of the most efficient way to collect genome-scale data, which can significantly augment studies that aimed to investigate patterns and histories of organisms at both intraspecific and high level. Here, I showed the advancement of shifting from single-gene method to genomic approach and the benefit of applying exon capture method comparing to alternative genomic techniques. Then, I explained the principle of exon capture method as well as providing detailed recommendations for applying this method. Finally, I demonstrated exon capture method using two applications and discussed future perspectives of this technology.

• The Journal of Bigdata
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• v.8 no.2
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• pp.15-25
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• 2023

Extreme learning machines (ELMs) are a major analytical method in various prediction fields. ELMs can accurately predict even if the data contains noise or is nonlinear by learning the complex patterns of time series data through optimal learning. This study presents the recent trends of machine learning models that are mainly studied as tools for analyzing online time series data, along with the application characteristics using existing algorithms. In order to efficiently learn large-scale online data that is continuously and explosively generated, it is necessary to have a learning technology that can perform well even in properties that can evolve in various ways. Therefore, this study examines a comprehensive overview of the latest machine learning models applied to big data in the field of time series prediction, discusses the general characteristics of the latest models that learn online data, which is one of the major challenges of machine learning for big data, and how efficiently they can learn and use online time series data for prediction, and proposes alternatives.

• The Journal of the Petrological Society of Korea
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• v.17 no.1
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• pp.16-35
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• 2008

We study metamorphism of metasedimetary rocks and origin and evolution of leucogranite form Samcheok area, northeastern Yeongnam massif, South Korea. Metamorphic rocks in this area are composed of metasedimentary migmatite, biotite granitic gneiss and leucogranite. Metasedimentary rocks, which refer to major element feature of siliclastic sediment, are divided into two metamorphic zones based on mineral assemblages, garnet and sillimanite zones. According to petrogenetic grid of mineral assemblages, metamorhpic P-T conditions are $740{\sim}800^{\circ}C$ at $4.8{\sim}5.8\;kbar$ in the garnet zone and $640-760^{\circ}C$ at 2.5-4.5kbar in sillimanite zone. The leucogranite (Imwon leucogranite) is peraluminous granite which has high alumina index (A/CNK=1.31-1.93) and positive discriminant factor value (DF > 0). Thus, leucogranite is S-type granite generated from metasedimentary rocks. Major and trace element diagram ($R_1-R_2$ diagram and Rb vs. Y+Nb etc.) show collisional environment such as syn-collisional or volcanic arc granite. Because Rb/sr ratio (1.8-22.9) of leucogranites is higher than Sr/Ba ratio (0.21-0.79), leucogranite would be derived from muscovite dehydrate melting in metasedimentary rocks. Leucogranites have lower concentration of LREE and Eu and similar that of HREE relative to metasedimentary rocks. To examine difference of REEs between leucogranites and metasedimentary rocks, we perform modeling using volume percentage of a leucogranite and a metasedimenatry rock from study area and REE data of minerals from rhyolite (Nash and Crecraft, 1985) and melanosome of migmatite (Bea et al., 1994). Resultants of modeling indicate that LREE and HREE are controlled by monazites and garnet, respectively, although zircon is estimated HREE dominant in some leucogranite without garnet. Because there are many inclusions of accessary phases such as monazite and zircon in biotites from metasedimentary rocks. leucogranitic magma was mainly derived from muscovite-breakdown in metasedimenary rocks. Leucogranites can be subdivided into two types in compliance with Eu anomaly of chondrite nomalized REE pattern; the one of negative Eu anomaly is type I and the other is type II. Leucogranites have lower Eu concetnrations than that of metasedimenary rocks and similar that of both type. REE modeling suggest that this difference of Eu value is due to that of components of feldspars in both leucogranite and metasedimentary rock. The tendency of major ($K_2O$ and $Na_2O$) and face elements (Eu, Rb, Sr and Ba) of leucogranites also indicate that source magma of these two types was developed by anatexis experienced strong fractionation of alkali-feldspar. Conclusionally, leucogranites in this area are products of melts which was generated by muscovite-breakdown of metasedimenary rock in environment of continetal collision during high temperature/pressure metamorphism and then was fractionated and crystallized after extraction from source rock.

• Journal of the Korean Geographical Society
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• v.47 no.4
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• pp.606-624
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• 2012

The main objective of this paper is to provide an adequate and comprehensive review of what has been done in South Korea in the field of geospatial analysis and modeling. This review focuses on spatial data analysis and spatial statistics, spatial optimization, and geosimulation among various aspects of the field. It is recognized that geospatial analysis and modeling in South Korea got through the initial stage during the 1990s when computer and analytical cartography and GIS were introduced, moved to the growth stage during the first decade of the $21^{st}$ century when there was a surge of relevant researches, and now is heading for its maturity stage. In spatial data analysis and spatial statistics, various topics have been addressed for spatial point pattern data, areal data, geostatistical data, and spatial interaction data. In spatial optimization, modeling and applications related to facility location problems, districting problems, and routing problems have been mostly researched. Finally, in geosimulation, while most of research has focused on cellular automata, studies on agent-based model and simulation are in beginning stage. Among all these works, some have fostered methodological advances beyond simple applications of the standard techniques.

• Applied Microscopy
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• v.39 no.2
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• pp.89-99
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• 2009

To investigate the morphological characteristics of spermatozoa of the grey red-blacked vole (Clethrionomys rufocanus) belongings to the subfamily Cricetinae, subgenus Clethrionomys were examined by scanning and transmission electron microscopes. The sperm head of C. rufocanus was an ax or hatchet in shape with a curved single dorsal hook. The total length of C. regulus sperm was 95.8 ${\mu}m$. The length of sperm head was 7.8 ${\mu}m$, and the tail (88.0 ${\mu}m$) consisted of four major segments: the neck (1.0 ${\mu}m$), middle piece (22.0 ${\mu}m$), and principal piece plus end piece (65.0 ${\mu}m$), respectively. The segmented columns were about 10~12 in number. The number of gyres of mitochondria ranged from about 170 to 178. The post-nuclear cap occupied about a half of nucleus. The equatorial segment is located between the post-nuclear cap segment and acrosomal cap on the nuclear surface. Nos. 1, 5 and 6 of the outer dense fibers were larger than the others. A fibrous sheath and longitudinal column of the principal piece were in evidence, but the fibrous sheath was not seen at the end piece. In conclusion, the morphological structures of sperm head and tail may be useful information to patterning of sperm evolution and classifying of species.

• Information Systems Review
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• v.10 no.2
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• pp.137-158
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• 2008

Rapid development of various information technologies creates new opportunities in online and offline markets. In this changing market environment, customers have various demands on new products and services. Therefore, their power and influence on the markets grow stronger each year. Companies have paid great attention to customer relationship management. Especially, personalized product recommendation systems, which recommend products and services based on customer's private information or purchasing behaviors in stores, is an important asset to most companies. CRM is one of the important business processes where reliable information is mined from customer database. Data mining techniques such as artificial intelligence are popular tools used to extract useful information and knowledge from these customer databases. In this research, we propose a recommendation system that predicts customer's purchase intention. Then, customer's purchasing intention of specific product is predicted by using data mining techniques using receipt data set. The performance of this suggested method is compared with that of other data mining technologies.

• Journal of Conservation Science
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• v.32 no.2
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• pp.123-139
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• 2016

The excavated potteries of Goryeo Period from the Sandongri archaeological site in Seosan were studied on physicochemical analyses. Surface color of the samples are mainly grayish blue, and showed the natural glaze by melting the body soils during the burning. Partly, swelling surface are observed bloated marks because of blow out gas by burning. The potteries are some possibility of making the similar source clay on the basis of magnetic susceptibilities (about $1{\times}10^{-3}SI\;unit$) and general occurrences. Values of specific gravity, apparent porosity and absorption ratio are divided two groups as highly different cases of bloating surface samples. The source clay of the potteries used mainly microcrystalline clay, the mineral compositions are quartz and some colored minerals. Based on the analysis, the burning temperature of the potteries are assumed that they were around $1,100^{\circ}C$ because detection of quartz and mullite within hard and compact matrices. As geochemical variations of the samples, evolution trends of rare earth, compatible and incompatible elements showed very similar patterns excepting the some major elements, that means the potteries are interpreted to making by elutriation processes using the same raw clays from very similar basement rocks of genetically.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.296-305
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• 2017

This study aims to create a new urban space through mechanism structure and algorism analysis between IT and ET. The results are as follows. First, the development trends of ET IT are classified into 4 types, "Eco-Friendly Development", "Energy Production Technology Development", "Energy Saving Technology Development" and "Wide Area IT Network Development", which are found to be constantly evolving. Second, Sang-Am DMC developed through the environmentally protective and eco-friendly aspects of ET from the Korean War to 1978. Wide area IT networks developed rapidly from 1990 to 2000. However, in 2010, urban spaces began to develop by the fusion of the Environment and Information. The fusion of Environment and Information in the development trends in the past is referred to as "Individual Development", that in the present is referred to as "Semi-fusion Development" and that in the future will be referred to as "Total Fusion Development". Third, the mechanism structure of DMC has evolved through creation, extinction and fusion processes. The creation process will serve to supplement the insufficiencies of the existing systems, the extinction process will be the compactification of the fusion process, and the fusion process will be the standard for creation and extinction. Finally, the future of new innovative urban and architectural spaces will be forged by the mechanism symbolization patterns of IT ET.