• Journal of Korea Water Resources Association
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• v.51 no.6
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• pp.503-514
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• 2018

In recent, the hydrological regime of the Mekong river is changing drastically due to climate change and haphazard watershed development including dam construction. Information of hydrologic feature like streamflow of the Mekong river are required for water disaster prevention and sustainable water resources development in the river sharing countries. In this study, runoff simulations at the Kratie station of the lower Mekong river are performed using SWAT (Soil and Water Assessment Tool), a physics-based hydrologic model, and LSTM (Long Short-Term Memory), a data-driven deep learning algorithm. The SWAT model was set up based on globally-available database (topography: HydroSHED, landuse: GLCF-MODIS, soil: FAO-Soil map, rainfall: APHRODITE, etc) and then simulated daily discharge from 2003 to 2007. The LSTM was built using deep learning open-source library TensorFlow and the deep-layer neural networks of the LSTM were trained based merely on daily water level data of 10 upper stations of the Kratie during two periods: 2000~2002 and 2008~2014. Then, LSTM simulated daily discharge for 2003~2007 as in SWAT model. The simulation results show that Nash-Sutcliffe Efficiency (NSE) of each model were calculated at 0.9(SWAT) and 0.99(LSTM), respectively. In order to simply simulate hydrological time series of ungauged large watersheds, data-driven model like the LSTM method is more applicable than the physics-based hydrological model having complexity due to various database pressure because it is able to memorize the preceding time series sequences and reflect them to prediction.

• Korean Journal of Microbiology
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• v.50 no.3
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• pp.210-215
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• 2014

Pseudomonas nitroreducens TX1 was isolated from a rice field drainage in Taiwan. The bacterium is of special interest because of its capability to use a group of nonionic surfactants such as alkylphenol polyethoxylates even at high concentrations as a sole carbon source. In this study, a small cryptic circular plasmid, pTX1, was characterized from P. nitroreducens TX1. It is 2,286 bp in length with a GC content of 63.3% and harbors three open reading frames, $Rep_{pTX1}$ and functionally unidentified ORF1 and ORF2. The predicted $rep_{pTX1}$ gene product is homologous to Rep proteins of plasmids belonging to the pC194/pUB110 family, which is predominantly found in Gram-positive bacteria and is known to replicate by the rolling-circle mechanism. The copy number of pTX1 was estimated to be about 150 in each cell. Based on the genetic fingerprints and comparison with other plasmids, it is concluded that pTX1 replicates by a rolling circle mechanism which is rarely found for Pseudomonas plasmids.

• Journal of Internet of Things and Convergence
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• v.6 no.3
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• pp.75-80
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• 2020

Recently, the size of the IoT sensor has been decreased and the collecting direction of the IoT sensor for acquiring the data have been changed from 2D to 3D. It makes sensor structure complex. In the fabrication of the complex structure, 3D printing technology has more useful than traditional manufacturing technologies. Among 3D printing technologies, FDM (fused deposition modeling) is a candidate technology to fabricate a small IoT sensor because the price of the machine and the material is cheap. In the FDM process, a 3D shape is made by depositing the melted filament. Recently, the patent of FDM technology is expired and cheat machines are developed based on the open-source. In the FDM process, mechanical properties of a fabricated part is affected by a lots of factors such as the kind of material and process parameters. Among them, infill is affecting the mechanical properties and the production lead time as well. In this work, a new method to optimize the FDM process with the consideration of mechanical property and production lead time was proposed. To verify the method, the fabrications were performed with the different infill rates. The results of tensile tests were analyzed to verify the proposed method.

• Journal of Distribution Science
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• v.12 no.12
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• pp.83-92
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• 2014

Purpose - A business ecosystem refers to mutually dependent systems interconnected by a loose foundation of various ecosystem members such as customers, suppliers, partners, and other stakeholders. The ecosystem-based strategy attempts to achieve competitive advantage for firms by enriching a business ecosystem or building a sustainable business ecosystem through the collaboration and co-evolution of its members. A sustainable business ecosystem is a source of competitiveness for firms anda manageable resource for gaining a competitive advantage. Customers represent the core membership of the business ecosystem and play a pivotal role in building a sustainable business ecosystem. This study examines the effects of customer participation on economic and social value in the business ecosystem and suggests a course of action for building a sustainable business ecosystem. Research design, data, and methodology - Two business cases of South Korea are selected from two different business types: business-to-business (B2B) and business-to-customer (B2C) firms. Business ecosystems for B2B and B2C firms reflect contrasting characteristics. Data was collected from in-depth interviews with four representatives of four firms. Results - The study suggested seven propositions for the relationships between customer participation and a sustainable business ecosystem through multiple case studies based on in-depth interviews. The results reveal the following four strategic actions for building sustainable business ecosystems based on the suggested propositions: alignment, systemization, socialization, and co-evolution. Alignment refers to achieving a harmonic balance or virtuous circle among the firm's mission, investment, and value creation. Systemization refers to building and implementing management and infrastructure systems rooted in the corporate culture. Socialization of customers in the business ecosystem reinforces the harmony or virtuous cycle. Finally, co-evolution is associated with the relationship between firms and customers as buyer firms in a restricted business ecosystem. Conclusions - This study considers multiple cases for the execution of a sustainable business ecosystem in collaboration with customers and suggests seven propositions and four strategic actions. The results are based on qualitative data from interviews with business associates from two firms in an open business ecosystem and two firms in a restricted business ecosystem, both in South Korea. Our research results regarding two contrasting business ecosystems shed light on business issues and policy making in Asian business environments, which are in the transition stages from a traditional conglomerate-driven to an inclusive growth-driven economy. The business ecosystem itself should be considered a manageable resource for firms' competitive positions in the market. A customer is a member of the business ecosystem and should thus be viewed not only as a purchasing entity and an object of relationship management but also as a co-creator of value. Therefore, firms should collaborate with customers to build sustainable business ecosystems. For this, firms must create social value, which cannot be created by customers alone, within the business ecosystem. Then, customers participate in a business ecosystem and build it to be favorable to them. Implications for academics and practitioners were suggested.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.1
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• pp.57-70
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• 2018

The advancement and the spread of information and communication technology (ICT) changes the way we live and act. Computer and ICT devices become smaller and invisible, and they are now virtually everywhere in the world. Many socio-economic activities are now subject to the use of computer and ICT devices although we don't really recognize it. Various socio economic activities supported by digital devices leave digital records, and a myriad of these records becomes what we call'big data'. Big data differ from conventional data we have collected and managed in that it holds more detailed information of socio-economic activities. Thus, they offer not only new insight for our society and but also new opportunity for policy analysis. However, the use of big data requires development of new methods and tools as well as consideration of institutional issues such as privacy. The goals of this research are twofold. Firstly, it aims to understand the opportunities and challenges of using big data for planning support. Big data indeed is a big sum of microscopic and dynamic data, and this challenges conventional analytical methods and planning support tools. Secondly, it seeks to suggest ways of visualizing such spatial big data for planning support. In this regards, this study attempts to develop a dynamic visualization model and conducts an experimental case study with mobile phone big data for the Jeju island. Since the off-the-shelf commercial software for the analysis of spatial big data is not yet commonly available, the roles of open source software and computer programming are important. This research presents a pilot model of dynamic visualization for spatial big data, as well as results from them. Then, the study concludes with future studies and implications to promote the use of spatial big data in urban planning field.

• Journal of Animal Science and Technology
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• v.47 no.2
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• pp.177-186
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• 2005

Xenotransplantation may help to overcome the critical shortage of human tissues and organs for human transplantation, Swine represents an ideal source of such organs owing to their anatomical and physiological similarities to human besides their plentiful supply, However, the use of organs across the species barrier may be associated with the risk of transmission of pathogens, specially porcine endogenous retroviruses (PERVs).• Although most of these potential pathogens could be eliminated by pathogen-free breeding, PERVs are not eliminated by this treatment. PERVs are integrated into the genome of all pigs and produced by normal pig cells and infect human cells. They belong to gamma retroviruses and are of three classes viruses: A, B and C. In the present study, PCR based cloning was performed with chromosomal DNA extracted from pigs from domestic pigs in Korea. Amplified PCR fragments of about 1.5 Kb, covering the partial env gene, were cloned into pCR2.l-TOPO vectors and sequenced. A total of 91 env clones were obtained from domestic pigs, Berkshire, Duroc, Landrace and Yorkshire in Korea. Phylogenetic analysis of these genes revealed the presence of only PERV class A and B in the proportion of 58 % and 42 %, respectively. Among these, 28 clones had the correct open reading frame: 18 clones in class A and 10 clones in class B. Since both these PERV classes are polytropic and have the capacity to infect human cells, our data suggest that proviral PERVs have the potential to generate infectious viruses during or after xenotransplantation in human.

• Communications of Mathematical Education
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• v.29 no.1
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• pp.35-49
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• 2015

3D-Printing is one of the most innovative technologies that will be widely used in the 21st century. 3D-Printing also serves as an indispensable tool in STEAM education. In this article, we introduce what we have done in our mathematical modeling class in Uni. and recent R&E project under the support of Korean Foundation for the Advancement of Science and Creativity. We planned a model of STEAM education originating from our wish to make tangible models that use mathematical formulas to express the natural beauty of an object. We used a free, open-source software, Sage, to simulate these models online. Then, we created a program that generates a .STL file from these 3D images. This model can help students understand the natural beauty inherent in mathematics and use formulas and technology tools to simulate models in 3D. Finally, we were able to help students to create their own. STL files through a website we developed by adding Sage code into a Sage notebook. Then students can make and hold a 3D object of their very own. This process shows the possibility that mathematics, art and 3D-Printing can be effectively used to achieve the goals of STEAM education.

• Journal of the Society of Naval Architects of Korea
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• v.34 no.4
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• pp.31-41
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• 1997

This paper describes a potential-based panel method formulated for the prediction of the steady performance of a waterjet propulsor. The method employs normal dipoles and sources distributed on the solid surfaces such as the impeller/stator blades, hub and duct, and normal dipoles in the shed wakes trailing the impeller and stator to represent the potential flow around the waterjet propulsor. To define a closed boundary surface, the inlet and outlet open boundary surfaces are introduced where the sources and dipoles are distributed. The kinematic boundary condition on the solid boundary surface is satisfied by requiring that the normal component of the total velocity should vanish. On the inlet surface, the total inflow flux into the duct is specified, and on the outlet surface the conservation of mass principle is applied to evaluate the source strength. The solid surfaces are discretized into a set of quadrilateral panel elements and the strengths of sources and dipoles are assumed constant at each panel. Applying this approximation to the boundary conditions leads to a set of simultaneous equations. Systematic numerical tests show that the present numerical method is fast and stable. In order to validate the present method, sample computations are carried out first for the case of a conventional axial flow fan which has a similar geometry as the waterjet propulsor, and then for the case of a waterjet propulsor on which experiments are carried out at KRISO(Korea Research Institute of Ships and Ocean Engineering).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.4
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• pp.436-441
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• 2015

'Superhongmi' is a new rice variety with reddish brown color developed from a crossing a high cyanidin 3-glucoside (C3G) content beeeds including Heugjinju and Suwon 425 and a big grain size breed such as Daeribbyeo. This variety heads on Sep. 5 and has 86.7 cm culm length. The fertility ratio of Superhongmi was about 81.7% and weight of 1,000-grain was about 26.8 g. The 1,000 grain weight of Superhongmi was heavier than that of Superjami. The total essential amino acid content of Superhongmi was lower than those of others. However, Superhongmi was high in tyrosine and arginine. Total polyphenol content of Superhongmi was 2 times higher than that of Heugjinju and flavonoid content was 8 times higher than that of Dongjinbyeo. In addition, hydroxy radical scavenging activity of Superhongmi was significantly higher than that of Dongjinbyeo. However, significant differences were not found in the newly breed colored rice. These results suggest that Superhongmi variety has very high value as a source of various functional food as well as stable food.

• Journal of Internet Computing and Services
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• v.19 no.3
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• pp.67-77
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• 2018

This paper suggests that LOD establishes its own link policy and publishes it to LOD cloud to provide identity among entities in different LODs. For specifying the link policy, we proposed vocabulary set founded on RDF model as well. We implemented Policy based In-depth Searching and Cleansing(PISC for short) system that proceeds in-depth searching across LODs by referencing the link policies. PISC has been published on Github. LODs have participated voluntarily to LOD cloud so that degree of the entity identity needs to be evaluated. PISC, therefore, evaluates the identities and cleanses the searched entities to confine them to that exceed user's criterion of entity identity level. As for searching results, PISC provides entity's detailed contents which have been collected from diverse LODs and ontology customized to the content. Simulation of PISC has been performed on DBpedia's 5 LODs. We found that similarity of 0.9 of source and target RDF triples' objects provided appropriate expansion ratio and inclusion ratio of searching result. For sufficient identity of searched entities, 3 or more target LODs are required to be specified in link policy.