• Journal of Intelligence and Information Systems
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• v.27 no.1
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• pp.65-82
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• 2021

Stock market investors are generally split into foreign investors, institutional investors, and individual investors. Compared to individual investor groups, professional investor groups such as foreign investors have an advantage in information and financial power and, as a result, foreign investors are known to show good investment performance among market participants. The purpose of this study is to propose an investment strategy that combines investor-specific transaction information and machine learning, and to analyze the portfolio investment performance of the proposed model using actual stock price and investor-specific transaction data. The Korea Exchange offers daily information on the volume of purchase and sale of each investor to securities firms. We developed a data collection program in C# programming language using an API provided by Daishin Securities Cybosplus, and collected 151 out of 200 KOSPI stocks with daily opening price, closing price and investor-specific net purchase data from January 2, 2007 to July 31, 2017. The self-organizing map model is an artificial neural network that performs clustering by unsupervised learning and has been introduced by Teuvo Kohonen since 1984. We implement competition among intra-surface artificial neurons, and all connections are non-recursive artificial neural networks that go from bottom to top. It can also be expanded to multiple layers, although many fault layers are commonly used. Linear functions are used by active functions of artificial nerve cells, and learning rules use Instar rules as well as general competitive learning. The core of the backpropagation model is the model that performs classification by supervised learning as an artificial neural network. We grouped and transformed investor-specific transaction volume data to learn backpropagation models through the self-organizing map model of artificial neural networks. As a result of the estimation of verification data through training, the portfolios were rebalanced monthly. For performance analysis, a passive portfolio was designated and the KOSPI 200 and KOSPI index returns for proxies on market returns were also obtained. Performance analysis was conducted using the equally-weighted portfolio return, compound interest rate, annual return, Maximum Draw Down, standard deviation, and Sharpe Ratio. Buy and hold returns of the top 10 market capitalization stocks are designated as a benchmark. Buy and hold strategy is the best strategy under the efficient market hypothesis. The prediction rate of learning data using backpropagation model was significantly high at 96.61%, while the prediction rate of verification data was also relatively high in the results of the 57.1% verification data. The performance evaluation of self-organizing map grouping can be determined as a result of a backpropagation model. This is because if the grouping results of the self-organizing map model had been poor, the learning results of the backpropagation model would have been poor. In this way, the performance assessment of machine learning is judged to be better learned than previous studies. Our portfolio doubled the return on the benchmark and performed better than the market returns on the KOSPI and KOSPI 200 indexes. In contrast to the benchmark, the MDD and standard deviation for portfolio risk indicators also showed better results. The Sharpe Ratio performed higher than benchmarks and stock market indexes. Through this, we presented the direction of portfolio composition program using machine learning and investor-specific transaction information and showed that it can be used to develop programs for real stock investment. The return is the result of monthly portfolio composition and asset rebalancing to the same proportion. Better outcomes are predicted when forming a monthly portfolio if the system is enforced by rebalancing the suggested stocks continuously without selling and re-buying it. Therefore, real transactions appear to be relevant.

• Journal of the Korean earth science society
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• v.35 no.6
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• pp.439-466
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• 2014

Since the unification of the diverse oceanic current maps of the East Sea in secondary school science textbooks has recently been accomplished, there have been increasing requirements for the production of a current map of the Yellow Sea (YS) and the East China Sea (ECS). This study, as its first attempt, facilitated the prospective production process of the unified oceanic current maps in YS and ECS by analyzing the maps of scientific articles and those of the present textbooks as of 2014. First of all, the analogue current maps of the textbooks and scientific articles were digitalized to retrieve the characteristics of current maps quantitatively and to make intercomparison of the maps. The currents of both YS and ECS such as the Kuroshio Current, the Taiwan Warm Current, the Tsushima Warm Current, the Yellow Sea Warm Current, the Chinese Coastal Current, the Korea Coastal Current, and the Changjiang River Flow were selected and analyzed. We made 18 items to investigate the paths of the currents. Analyses of the oceanic current maps of secondary school science textbooks and scientific articles with respect to the selected criteria revealed that the current maps of the textbooks were considerably different from the up-to-date knowledge of the current maps acquired from the scientific articles. In addition, since the currents of YS and ECS have strong seasonality, we suggest that they should be presented with at least two current maps for summer and winter in the textbooks, which may go through active discussions among experts.

• The Plant Pathology Journal
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• v.30 no.4
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• pp.343-354
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• 2014

Rice blast disease caused by Magnaporthe oryzae is one of the most serious diseases of cultivated rice (Oryza sativa L.) in most rice-growing regions of the world. In order to investigate early response genes in rice, we utilized the transcriptome analysis approach using a 300 K tilling microarray to rice leaves infected with compatible and incompatible M. oryzae strains. Prior to the microarray experiment, total RNA was validated by measuring the differential expression of rice defense-related marker genes (chitinase 2, barwin, PBZ1, and PR-10) by RT-PCR, and phytoalexins (sakuranetin and momilactone A) with HPLC. Microarray analysis revealed that 231 genes were up-regulated (>2 fold change, p < 0.05) in the incompatible interaction compared to the compatible one. Highly expressed genes were functionally characterized into metabolic processes and oxidation-reduction categories. The oxidative stress response was induced in both early and later infection stages. Biotic stress overview from MapMan analysis revealed that the phytohormone ethylene as well as signaling molecules jasmonic acid and salicylic acid is important for defense gene regulation. WRKY and Myb transcription factors were also involved in signal transduction processes. Additionally, receptor-like kinases were more likely associated with the defense response, and their expression patterns were validated by RT-PCR. Our results suggest that candidate genes, including receptor-like protein kinases, may play a key role in disease resistance against M. oryzae attack.

• Journal of the Korean Association of Geographic Information Studies
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• v.7 no.3
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• pp.13-21
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• 2004

The dissemination of commercial satellite images. which have the high spatial resolution such as aerial photos, are the active trend in remote sensing community because of the recent development in satellite and sensor technology. Such high resolution satellite images provide a unique tool for the monitoring of ongoing urban land use change. Especially KOMPSAT-1, which was launched at December 1999 and successfully operated up to now, provides repeatedly panchromatic images over Korean peninsula, which has the spatial resolution of 6.6m. Based upon this KOMPSAT-1 EOC image data we can try to analyze and assess the temporal urban land use change, which could not be done because lack of such data. The aim of this paper is to analyze and assess the spatial land use characteristics of Daejeon Metropolitan City based on KOMPSAT-1 EOC data. The land use map of year 2001 is generated through the modification of the year 2000 land use map, which is published by National Geographic Information Institute, using visual interpretation of KOMPSAT-1 EOC image which is acquired in year 2001. This study can be the start point of the time series analysis of the long term land use change monitoring mit KOMPSAT-1 EOC data.

• Korean Journal of Remote Sensing
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• v.36 no.2_2
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• pp.325-335
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• 2020

Forest canopy height can be used for estimate of above-ground forest biomass (AGB) by means of the allometric equation. The remote locations and harsh conditions of mangrove forests limit the number of field inventory data stations needed for large-scale modeling of carbon and biomass dynamics. Although active and passive spaceborne sensors have proven successful in mapping mangroves globally, the sensors generally have coarse spatial resolution and overlook small-scale features. Here we generate a 12 m spatial resolution mangrove canopy height map from TanDEM-X data acquired over the world largest intact mangrove forest located in the Sundarbans. With single-pol. TanDEM-X data from 2011 to 2013, the proposed technique makes use of the fact that the double-bounce scattering that occurs between the water and mangrove trees yields water surface level elevation over mangrove forest areas, thus allowing us to estimate forest height with the assumption of an underlying flat topography. Our observations have led to a large-scale mangrove canopy height map over the entire Sundarbans region at a 12 m spatial resolution. Our canopy height estimates were validated with ground measurements acquired in 2015, a correlation coefficient of 0.83 and a RMSE of 0.84 m. With globally available TanDEM-X data, the technique described here will potentially provide accurate global maps of mangrove canopy height at 12 m spatial resolution and provide crucial information for understanding biomass and carbon dynamics in the mangrove ecosystems.

• Horticultural Science & Technology
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• v.31 no.6
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• pp.813-820
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• 2013

Monoterpenoids were recently found as main biologically active compounds which is responsible for various physiological effect in goat's beard (Aruncus dioicus). Ethyl acetate extract of A. dioicus (ADE) was treated to B16F10 melanoma cells for the examination of whitening activity. MTT assay was performed to evaluate cell toxicity and the result showed that slight cell toxicity (> 10%) by over $500{\mu}g{\cdot}mL^{-1}$. Thus, 0, 5, 10, or $50{\mu}g{\cdot}mL^{-1}$ ADE was used for further experiments. We found that tyrosinase activity was decreased according to ADE concentration, and the total melanin content was also dramatically reduced. Especially with $50{\mu}g{\cdot}mL^{-1}$ ADE treatment tyrosinase activity was reduced to 35.6%, and 58.8% of melanin content was lowered. In addition, whitening related proteins including tyrosinase, tyrosinase related protein 1 (TRP1), TRP2, microphthalmia associated transcription factor (MITF) and cAMP and protein kinase A (PKA) were reduced by ADE treatment. It caused decreased phosphorylation of cAMP response binding protein (CREB) but increased phosphorylation of extracellular signal related kinase (ERK). Therefore, in this paper we would like to suggest the potent usage of A. dioicus natively grown in Ulleungdo, Korea as materials of functional cosmetics by confirming whitening activity related with melanin content.

• Journal of Broadcast Engineering
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• v.15 no.2
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• pp.163-172
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• 2010

The free viewpoint video delivers an active contents where users can see the images rendered from the viewpoints chosen by them. Its applications are found in broad areas, especially museum tour, entertainment and so forth. As a new free-viewpoint application, this paper presents a stereoscopic free-viewpoint TIP (Tour Into Picture) where users can navigate the inside of a single image controlling a virtual camera and utilizing depth data. Unlike conventional TIP methods providing 2D image or video, our proposed method can provide users with 3D stereoscopic and free-viewpoint contents. Navigating a picture with stereoscopic viewing can deliver more realistic and immersive perception. The method uses semi-automatic processing to make foreground mask, background image, and depth map. The second step is to navigate the single picture and to obtain rendered images by perspective projection. For the free-viewpoint viewing, a virtual camera whose operations include translation, rotation, look-around, and zooming is operated. In experiments, the proposed method was tested eth 'Danopungjun' that is one of famous paintings made in Chosun Dynasty. The free-viewpoint software is developed based on MFC Visual C++ and OpenGL libraries.

• The Journal of the Petrological Society of Korea
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• v.18 no.3
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• pp.237-253
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• 2009

The lava flows forming the Manjanggul lava tube are commonly said to have a potential source from the Geomunoreum scoria cone. We inferred the source of lava flows with the Manjanggul lava tube, based on many studies about lava tubes within lava flows of active volcano in the world. We made a lava flow field map from lithofacies, features and latitude of lava surfaces in the northeastern part of Jeju Island, and then examined closely the distribution and mutual relation of lava tubes in each lava flow field. As result, the Geomunoreum lava tube system is divided into a series of master tubes(Utsanjeungul, Bukoreumgul, Daerimdonggul, Manjanggul, Gimnyeonggul, Yongcheondonggul and Dangcheomuldonggul lava tube), a complicated networks of small tubes(Bengdwigul lava tube), and a series of unitary tubes(Gimyeongbilemotgul~Gaeusaemgul lava tube) in Geomunoreum lava flows. Particularly a canyon, 2km in length to NNE direction from the Geomunoreum scoria cone, is interpreted to be collapse trench of lava tube roof that belongs to an upflow part of the master tube in the Geomunoreum lava tube system, according to the location and direction. Accordingly, the source of lava flows, forming the Manjanggul lava tube, is the Geomunoreum scoria cone.

• Development and Reproduction
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• v.10 no.3
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• pp.169-175
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• 2006

Ginseng is the best known and most popular herbal medicine used worldwide. In spite of reported beneficial effects of ginseng on the CNS, there is few scientific evidences established at the cellular level. Among more than 30 ginsenosides, Rb1 and Rg1, the active ingredients of ginseng, are regarded as the main compounds responsible for many pharmaceutical actions of ginseng. Daily treatment with Rb1 or Rg1 for 3 d significantly decreased the number of bromodeoxyuridine(BrdU)(+) cells in primary neural progenitor cells(NPCs) isolated from hippocampi at embryonic day 16.5(E16.5). In contrast, treatment with Rb1 or Rg1 greatly increased the number of microtubule associated protein(MAP2) (+) cells. In addition, the transcription factors, Ngn1 and Hes1, proneural members of the basic helix-loop-helix(bHLH) family, significantly increased in Rb1 or Rg1 treated-NPCs. Based on these results, we suggest for the first time that ginsenosides Rb1 and Rg1 decrease proliferation but promote neuronal differentiation of hippocampal NPCs.

• International Journal of Computer Science & Network Security
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• v.22 no.7
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• pp.451-458
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• 2022

This article is devoted to the problem of national and patriotic education of young students by means of digital technologies in the conditions of distance learning environment. It is emphasized that national and patriotic education is a powerful means of strengthening the unity and integrity of Ukraine. It is proved that national and patriotic education will be effective under the condition of systematic and purposeful activity on formation of patriotic consciousness in youth, sense of national dignity, necessity of service of ideals and values of the country. Various forms of educational work of national and patriotic orientation at Pavlo Tychyna Uman State Pedagogical University, which were conducted by digital technologies: online thematic lectures, educational classes, round tables, workshops, guest online meetings with famous researchers of historical heritage of Ukraine, online tours of historical places, virtual exhibitions of art, participation in the national-patriotic student camp "Diia" (Action) and etc. The activity of the University Library and V. O. Sukhomlinsky State Scientific and Pedagogical Library of Ukraine of the National Academy of Pedagogical Sciences of Ukraine, which has a significant impact on the formation of national consciousness and social and political activity of students by modern means of information and communication technologies. It is determined that the project "Inclusive 3D map" helps to broaden the horizons and deepen the knowledge of young students, education of a true citizen, the formation of cognitive interest in the subjects studied, motivation to study, raising awareness of Ukrainians on historical and cultural heritage. The study showed that young students take an active social attitude: they speak Ukrainian, want to live and work in Ukraine, respect their homeland, its traditions, cultural and historical past, love to travel and they are tolerant of people with special needs. Promising areas of educational work with students based on the use of a wide range of information and communication technologies, namely 3D games, TV tandems, podcasts, social networks, video resources in national and patriotic education of youth.