• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.7
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• pp.1458-1464
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• 2005

A P2P is a method that can share and exchange on digital resources through a direct connection on personnel without a central server. In this paper, Although the P2P application that uses our proposed framework should obtain one or more IP addresses of the neighbor peers manually, after instantiate, the application can do its job while maintaining connection to the network continuously and automatically. To evaluate our proposed scheme, we measured and analyzed the time for a peer to reconnect to the network when the mediating peer fails and the network isolation occurs.

• Korean Journal of Crystallography
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• v.7 no.1
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• pp.57-63
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• 1996

The compound titanium (III) pyrophosphate, KTiP2O7 has been prepared and the crystal structure of the compound has been determined by the X-ray diffraction techniques. It crytallizes in the space group P21/a of the monoclinic system with four formula units in a cell of dimensions a=8.210(3), b=10.292(2), c=7.434(1)Å and β=106.71(2)°. The structure consists of the framework possessing corner-sharing octahedral TiO6 and pyrophosphate groups. As a result, a tunnel structure has been constructed and the K+ cations reside inside the tunnel. KTiP2O7 is isostructural with other trivalent metal pyrophosphates such as KAlP2O7 and RbTiP2O7 but the size difference of the alkali metals causes the variation in the structure. The classical charge balance of the compound can be described as [K+][Ti3+][P24O74-].

• Korean Journal of Microbiology
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• v.48 no.2
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• pp.73-78
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• 2012

We previously reported that the truncated Cel44C-$Man26A_{P558}$ ${\beta}$-glycosyl hydrolase protein exhibits multifunctional activities, including cellulase, xylanase, and lichenase. DNA shuffling of the truncated Cel44C-$Man26A_{P558}$ enzyme was performed to enhance the enzymatic activity of the multifunctional ${\beta}$-glycosyl hydrolase. Two mutant enzymes, M2Cel44C-$Man26A_{P558}$ that carries one mutation (P438A) and M21Cel44C-$Man26A_{P558}$ that carries two mutations (A273T and P438A) were obtained. The enzymatic activity of the M21Cel44C-$Man26A_{P558}$ double mutant was lower than enzymatic activity of the single mutant (M2Cel44C-$Man26A_{P558}$). However, both mutants displayed the enhancements in their enzyme activities that were ${\approx}1.3$- to 2.2-fold higher than the original enzymatic activity in Cel44C-$Man26A_{P558}$. In particular, the mutant M2Cel44C-$Man26A_{P558}$ exhibited an approximate 1.5- to 2.2-fold increase in the cellulase, xylanase, and lichenase activities in comparison with the control (Cel44C-$Man26A_{P558}$). The optimum cellulase, linchenase, and xylanase activities of ${\beta}$-glycosyl hydrolase were observed at pH 7.0, pH 7.0 and pH 6.0, respectively. These results, therefore, suggest that the amino acid residue Ala438 plays important roles in the enhancement of the activity of multifunctional ${\beta}$-glycosyl hydrolase.

• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.3
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• pp.98-106
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• 2010

This study focuses on the appropriate planting soil for Vitex rotundifolia by planting soil. Different soil depth levels were achieved at 15cm and 25cm in the green roof module system that was created with woody materials for a $500{\times}500{\times}300mm$ area. The soil mixture ratio was $S_{10}$, $L_{10}$, $S_7L_3$, $S_5L_5$, $P_7P_1L_2$, $P_6P_2L_2$, $P_5P_3L_2$ and $P_4P_4L_2$. This study was carried out over five months between April and September, 2006. The amount of soil moisture tends to decrease according to the planting soil. For the experimental items $S_{10}$, $S_7L_3$ and $S_5L_5$, the amount of soil moisture tends to decrease rapidly. However, for the experimental items $P_7P_1L_2$, $P_6P_2L_2$, $P_5P_3L_2$ and $P_4P_4L_2$, conditions containing perlite and peat moss, the amount of moisture tends to decrease more gradually. As a result, the use of soil-improving amending for the afforestation planting of roofs with a low level of management is need. After experimenting with the ratio of soil mixture for Vitex rotundifolia, the planting soil for experimental item $P_6P_2L_2$, $P_5P_3L_2$ and $P_4P_4L_2$ appeared excellent. For experimental item $S_{10}$, the growth of Vitex rotundifolia seemed to be weaker than that of others, because of the low levels of moisture and organic matter in the soil. For experimental item $L_{10}$, there appeared to be a low level of growth, even when the levels of moisture and organic matter were high. This may have occurred because of the low level of soil pH and the excessive amount of exchangeable cation. At the depth of 25cm, the growth of Vitex rotundifolia is vigorous overall. For experimental item at 15cm, Vitex rotundifolia was able to survive for 14 days without any rainfall and Vitex rotundifolia was better in amended soil, $P_6P_2L_2$, $P_5P_3L_2$ and $P_4P_4L_2$, than natural soil, SL.

• Journal of the Chungcheong Mathematical Society
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• v.35 no.4
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• pp.315-327
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• 2022

In this paper, we investigate the transferred superstability for the p-radical sine functional equation $$f\(\sqrt[p]{\frac{x^p+y^p}{2}}\)^2-f\(\sqrt[p]{\frac{x^p-y^p}{2}}\)^2=f(x)f(y)$$ from the p-radical functional equations: $$f({\sqrt[p]{x^p+y^p}})+f({\sqrt[p]{x^p-y^p}})={\lambda}g(x)g(y),\;\\f({\sqrt[p]{x^p+y^p}})+f({\sqrt[p]{x^p-y^p}})={\lambda}g(x)h(y),$$ where p is an odd positive integer, λ is a positive real number, and f is a complex valued function. Furthermore, the results are extended to Banach algebras. Therefore, the obtained result will be forced to the pre-results(p=1) for this type's equations, and will serve as a sample to apply it to the extension of the other known equations.

• Journal of the Korea Society of Computer and Information
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• v.17 no.2
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• pp.95-103
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• 2012

In this paper, we propose an efficient mobile P2P streaming architecture to minimize playback jitters in P2P overlay networks based on wired/wireless networks even though mobile peers experience the handover. In this architecture, mobile peers receive data in a push manner to maximize the data receiving speed before and after the handover. In addition, they can maintain the buffering above a specific level through handover prediction and re-selection of neighbor peers. By simulation experiments, we show that our proposed architecture can improve the performance significantly when the handover occurs compared to the existing mesh structure.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.411-413
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• 2010

Now, smart phone markets are grows quickly. So it is needed research of CDN(Contents Delivery Network) technology for contents transmission in mobile networks. Especially the services of smart phone are focused on open platform model. So P2P(Peer to Peer) protocols will be used for mobile network because it is a distributed network architecture composed of participants that make a portion of their resources directly available to other network participants, without the need for a central server. Current research of P2P protocols for mobile network are not activated. The reason is appropriate in the mobile P2P network simulation environment, since it is not provided. So, in this paper we design a mobile P2P simulation system for CDN based on mobile P2P.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.10
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• pp.3627-3641
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• 2021

Fintech, which stands for financial technology, is growing fast globally since the economic crisis hit the United States in 2008. Fintech companies are striving to secure a competitive advantage over existing financial services by providing efficient financial services utilizing the latest technologies. Fintech companies can be classified into several areas according to their business solutions. Among the Fintech sector, peer-to-peer (P2P) lending companies are leading the domestic Fintech industry. P2P lending is a method of lending funds directly to individuals or businesses without an official financial institution participating as an intermediary in the transaction. The rapid growth of P2P lending companies has now reached a level that threatens secondary financial markets. However, as the growth rate increases, so does the potential risk factor. In addition to government laws to protect and regulate P2P lending, further measures to reduce the risk of P2P lending accidents have yet to keep up with the pace of market growth. Since most P2P lenders do not implement their own credit rating system, they rely on personal credit scores provided by credit rating agencies such as the NICE credit information service in Korea. However, it is hard for P2P lending companies to figure out the intentional loan default of the borrower since most borrowers' credit scores are not excellent. This study analyzed the voices of telephone conversation between the loan consultant and the borrower in order to verify if it is applicable to determine the personal credit score. Experimental results show that the change in pitch frequency and change in voice pitch frequency can be reliably identified, and this difference can be used to predict the loan defaults or use it to determine the underlying default risk. It has also been shown that parameters extracted from sample voice data can be used as a determinant for classifying the level of personal credit ratings.

• Journal of the Korean Mathematical Society
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• v.54 no.2
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• pp.575-598
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• 2017

This paper introduces and studies a generalization of the classical Struve function of order p given by $$_aS_{p,c}(x):=\sum\limits_{k=0}^{\infty}\frac{(-c)^k}{{\Gamma}(ak+p+\frac{3}{2}){\Gamma}(k+\frac{3}{2})}(\frac{x}{2})^{2k+p+1}$$. Representation formulae are derived for $_aS_{p,c}$. Further the function $_aS_{p,c}$ is shown to be a solution of an (a + 1)-order differential equation. Monotonicity and log-convexity properties for the generalized Struve function $_aS_{p,c}$ are investigated, particulary for the case c = -1. As a consequence, $Tur{\acute{a}}n$-type inequalities are established. For a = 2 and c = -1, dominant and subordinant functions are obtained for the Struve function $_2S_{p,-1}$.

• Journal of Information Processing Systems
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• v.2 no.1
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• pp.6-12
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• 2006

Peer-to-Peer (P2P) networks are attracting considerable research interest because of their scalability and high performance relative to cost. One of the important services on a P2P network is the streaming service. However, because each node in the P2P network is autonomous, it is difficult to provide a stable streaming service on the network. Therefore, for a stable streaming service on the P2P network, a fault-tolerant scheme must be provided. In this paper, we propose two new node selection schemes, Playback Node First (PNF) and Playback Node first with Prefetching (PNF-P) that can be used for a service migration-based fault-tolerant streaming service. The proposed schemes exploit the fact that the failure probability of a node currently being served is lower than that of a node not being served. Simulation results show that the proposed schemes outperform traditional node selection schemes.