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Sosa-gu, South Korea

Kim Y.-H.,Korea University | Kim S.,Yuhan University
Journal of Electrical Engineering and Technology | Year: 2013

Resolvers are transducers that are used to sense the angular position of rotational machines. The analog resolver is necessary to use resolver to digital converter. Among the RDC software method, angle tracking observer (ATO) is the most popular method. In an actual resolver-based position sensing system, amplitude imbalance dominantly distorts the estimate position information of ATO. Minority papers have reported position error compensation of resolver's output signal with amplitude imbalance. This paper proposes new ATO algorithm in order to compensate position errors caused by the amplitude imbalance. There is no need premeasured off line data. This is easy, simple, cost-effective, and able to work on line compensation. To verify feasibility of the proposed algorithm, simulation and experiments are carried out. Source


Choi D.-Y.,Yuhan University
Advanced Science Letters | Year: 2014

We propose two phase Web personalization method for smartphones. The proposed approach is effective for reflecting both private personalization and collaboration personalization. At present, Web personalization is generally achieved by using private personalization such as Web server log, Google’s Web history, etc. In this paper, collaboration personalization is derived from the weighting order of keywords based on SNS data such as Facebook, Twitter, etc. We also propose Web page ranking algorithm applying collaboration personalization to the collection of Web pages based on private personalization. Thus, the proposed Web search engine can provide users with trend-based page ranking. It is particularly useful to find current focal issues such as trend, what’s new, etc., on the Web. © 2014 American Scientific Publishers All rights reserved. Source


Choi D.-Y.,Yuhan University
Advanced Science Letters | Year: 2014

Handling fuzzy query in voice search on smartphones is one of the most difficult problems. It is mainly derived from the complexity and the degree of freedom of natural language. To reduce the complexity and the degree of freedom of fuzzy query in voice search on smarphones, attribute-driven approach for fuzzy query is proposed. In this paper, we design a prototype model for handling fuzzy query in voice search on smartphones. It is based on voice web search, user's physical location, search distance, search directory and user's search intentions. The filtering ratio on search results of the proposed approach compared to existing smartphones is presented. It is a further step towards location-based personalized voice search (LPVS) for smartphone users. © 2014 American Scientific Publishers All rights reserved. Source


Yoon T.J.,Yuhan University | Koppula S.,Konkuk University | Lee K.H.,Konkuk University
Anti-Cancer Agents in Medicinal Chemistry | Year: 2013

Beta-glucans (β-glucans), naturally occurring polysaccharides, are present as constituents of the cell wall of cereal grains, mushrooms, algae, or microbes including bacteria, fungi, and yeast. Since Pillemer et al. first prepared and investigated zymosan in the 1940s and others followed with the investigation of β-glucans in the 1960s and 1970s, researchers have well established the significant role of β-glucans on the immune system relative to cancer treatment, infection immunity, and restoration of damaged bone marrow. However, information on their biological role in anti-metastatic activity remains limited. As an immunomodulating agent, β-glucan acts through the activation of innate immune cells such as macrophages, dendritic cells, granulocytes, and natural killer cells. This activation triggers the responses of adaptive immune cells such as CD4+ or CD8+ T cells and B cells, resulting in the inhibition of tumor growth and metastasis. Reports have shown that β-glucans exert multiple effects on cancer cells and cancer prevention. However the mechanisms of their actions appear complex due to differences in source, chemical structure, insufficiently defined preparation, and molecular weight, hence the inconsistent and often contradictory results obtained. This review is focused on the potential of β-glucans as anti-metastatic agents and the known mechanisms underlying their biological effects. © 2013 Bentham Science Publishers. Source


Park N.S.,Yuhan University | Ko S.C.,Jeonju University
Journal of Mechanical Science and Technology | Year: 2011

Large eddy simulation (LES) of turbulent premixed flame stabilized by the bluff body is developed by using sub-grid scale combustion model based on the G-equation describing the flame front propagation. The basic idea of LES modeling is to evaluate the filtered-front speed, which should be enhanced in the grid scale by the scale fluctuations. The dynamic sub-grid scale models newly introduced into the G-equation are validated by the premixed combustion flow behind the triangle flame holder. The objective of this study is to investigate the validity of the dynamic sub-grid G-equation model to a complex turbulent premixed combustion such as bluff body stabilized turbulent premixed flames for realistic engineering application. A new turbulent flame speed model, introduced by the sub-grid turbulent diffusivity and the flame thickness, is also proposed and is compared with the usual model using sub-grid turbulent intensity and with the experimental data. The calculated results can predict the velocity and temperature of the combustion flow in good agreement with the experiment data. © 2011 The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg. Source

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