• Journal of the Korea Society of Computer and Information
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• v.13 no.7
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• pp.109-115
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• 2008

In the P2P distributed system, such peers don't always keep on-line status. P2P systems are different from the ordinary systems that such peers are organically operated as the elements of system. In this case, users using P2P system are able to loss the reliability. At this point, many P2P studies are tried to resolve these problems. In this paper, we suggest a P2P search algorithm for multidirectional processing about the resources to be downloading. In existing studies, the loading rate is very high to select new resources supported peer, so we suggest new solution in this study.

• The KIPS Transactions:PartD
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• v.11D no.4
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• pp.975-982
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• 2004

In current P2P concept, pure P2P and Hybrid P2P structures are used commonly. Gnutella and Ktella are forms of pure P2P. and forms of Hybrid P2P are innumerable. File searching models exist in these models. These models provide group management for file sharing, searching and indexing. The general file sharing model is good at maintaining connectivity. However, it is defective in group management. Therefore, this study approaches hierarchical structure in file sharing models through routing technique and backup system. This system was designed so that the user was able to maintain group efficiency and connection reliability in large-scale network.

• Journal of the Korean Institute of Landscape Architecture
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• v.39 no.1
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• pp.117-123
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• 2011

This study aims to suggest a suitable soil thickness and soil mixture ratio of a green roof system by verifying the growth of Chrysanthemum zawadskii var. coreanum as affected by different green roof systems using rainwater. The experimental planting grounds were made with different soil thicknesses(15cm, 25cm) and soil mixing ratios (SL, $P_7P_1L_2$, $P_6P_2L_2$, $P_5P_3L_2$, $P_4P_4L_2$) and with excellent drought tolerance. Ornamental value Chrysanthemum zawadskii var. coreanum was planted. The change in plant height, green coverage ratio, chlorophyll content, fresh weight, dry weight, and dry T/R ratio of Chrysanthemum zawadskii var. coreanum were investigated from April to October 2009. For 15cm soil thickness, the plant height of Chrysanthemum zawadskii var. coreanum was not significantly different as affected by the soil mixing ratio. However, it was found to be higher in the amended soil mixture, $P_7P_1L_2$, $P_6P_2L_2$, $P_5P_3L_2$ and $P_4P_4L_2$ than in the sandy loam soil, as it was SL overall. For 25cm soil the plant height differences were in order to SL < $P_7P_1L_2$, $P_6P_2L_2$, $P_5P_3L_2$ < $P_4P_4L_2$. The green coverage ratio was observed not to be different by soil mixing ratio with soil thickness of 15cm, but, the lowest green coverage ratio in the SL. In the 25cm soil thickness, the green coverage ratio was 86-89% with a good coverage rate overall. The change in chlorophyll contents with 15cm soil thickness was found to be the highest in the SL treatment and the lowest in the $P_5P_3L_2$ treatment. For 25cm thickness, the highest value was in the $P_4P_4L_2$ and SL, and the lowest in the$P_7P_1L_2$. Fresh weight and dry weight were larger in soil with 25cm thickness. Therefore, the growth of Chrysanthemum zawadskii var. coreanum as affected by a different green roof system for using rainwater was higher in soil with 25cm thickness than 15cm, and in PPL amended soil than in sandy loam.

• Journal of Environmental Science International
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• v.12 no.7
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• pp.689-695
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• 2003

The purpose of this study is to evaluate and to predict of eutrophication in lakes by using Vollenweider-OECD model and total phosphorus concentration and inflow rate which were measured in 1993∼2001. The results of study were as follows. The annual total phosphorus loading from the watershed was calculated to be 55∼195tP/yr at lake Soyang, 221∼466tP/yr at lake Taechong, 123∼278tP/yr at lake Andong, 57∼109tP/yr at lake Seomjin. These are discharged, far the most parts, from population and fishfarm facility. TP loading on the surface area at lake Soyang was 3.01gP/㎡/yr, 2.82gP/㎡/yr, 2.84gP/㎡/yr, 3.03gP/㎡/yr, 2.34gP/㎡/yr, 1.78gP/㎡/yr, 0.91gP/㎡/yr, 0.89gP/㎡/yr, 0.86gP/㎡/yr, lake Taechong was 6.71gP/㎡/yr, 7.25gP/㎡/yr, 7.24gP/㎡/yr, 6.53gP/㎡/yr, 6.50gP/㎡/yr, 7.06gP/㎡/yr, 7.04gP/㎡/yr, 4.05gP/㎡/yr, 3.44gP/㎡/yr and TP loading on the surface area of lake Andong, lake Soemjin were 5.39gP/㎡/yr, 4.47gP/㎡/yr, 4.56gP/㎡/yr, 4.45gP/㎡/yr, 3.33gP/㎡/yr, 2.38gP/㎡/yr, 2.53gP/㎡/yr, 2.46gP/㎡/yr, 2.54gP/㎡/yr, 4.09gP/㎡/yr, 4.10gP/㎡/yr, 3.98gP/㎡/yr, 3.73gP/㎡/yr, 2.80gP/㎡/yr, 3.46gP/㎡/yr, 3.22gP/㎡/yr, 2.19gP/㎡/yr, 2.13gP/㎡/yr respectively. The tropic states of four lakes can be assessed as eutrophy because phosphorus leading exceeds the critical phosphorus loading by Vollenweider-OECD model.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.2
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• pp.1105-1117
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• 2017

Financial technology, also known as FinTech, is one of the fast growing global businesses in since its inception in 2008. Fintech is a new economic industry, comprised of companies that adopted the latest technologies to provide more efficient financial services than the traditional financial services. Fintech companies are generally small to medium sized startups trying to disintermediate existing financial systems. FinTech companies can be differentiated in several areas, based on its business solutions and target customers. In Korea, the Peer-to-Peer (P2P) lending companies are the most prominent in the FinTech sector. P2P lending is a method of borrowing or lending money to individuals through online services without the use of an official financial institution as an intermediary. The P2P lending companies operate their services entirely online or mobile environment. Consequently, mobile P2P lending application users are dramatically increasing. Thus, it is worth evaluating the acceptance of the mobile apps of the P2P lending companies from a user's perspective. This paper discusses user acceptance of the mobile P2P lending apps, guided by the Technology Acceptance Model. We conclude that the users' acceptance of mobile P2P lending apps are significantly influenced by perceived ease of use, perceived usefulness, and user satisfaction. These in turn influenced their attitude towards using mobile P2P lending apps and intention to use.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.5
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• pp.522-527
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• 2010

In the connected environment by network, clients shared resources as that requested the file that a server had, but P2P system is alternative because of the overload of servers. To improve the performance of this P2P system, we are studying about that. In this study, we can improve a usability for users using P2P search system, and suggest a group search algorithm based on a preprocessing search.

• Journal of information and communication convergence engineering
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• v.9 no.4
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• pp.396-400
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• 2011

P2P(peer to Peer) network 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. Currently, convergence network industry using wired and mobile are grows rapidly. So P2P protocols will be used between mobile and wired network. But current P2P protocols are focused on the wired networks only and there are no simulators for performance analysis of mobile P2P. In this paper, we design a P2P simulation system for performance analysis of P2P protocols in mobile, wired and convergence networks. It is constructed by a well-known mobile network simulator and wired based P2P protocol simulator. Finally we have implemented a smart TV test-bed using our P2P test-bed for convergence networks.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.6
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• pp.1401-1411
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• 2016

The Multi-Prime RSA and the Prime Power RSA are the variants of the RSA cryptosystem, where the Multi-Prime RSA uses the modulus $N=p_1p_2{\cdots}p_r$ for distinct primes $p_1,p_2,{\cdots},p_r$ (r>2) and the Prime Power RSA uses the modulus $N=p^rq$ for two distinct primes p, q and a positive integer r(>1). This paper analyzes the security of these systems by using the technique given by Heninger and Shacham. More specifically, this paper shows that if the $2-2^{1/r}$ random portion of bits of $p_1,p_2,{\cdots},p_r$ is given, then $N=p_1p_2{\cdots}p_r$ can be factorized in the expected polynomial time and if the $2-{\sqrt{2}}$ random fraction of bits of p, q is given, then $N=p^rq$ can be factorized in the expected polynomial time. The analysis is then validated with experimental results for $N=p_1p_2p_3$, $N=p^2q$ and $N=p^3q$.

• 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.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.1
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• pp.121-126
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• 2013

In the past several years there has been increasing the studies using P2P technology in the distributed system areas. In these P2P systems, the server to support the contents-information have less overloads than the composed system as the server to have resources generally. In this paper, we propose the system to support a social network P2P service based on the social network P2P system. The object of this study was to widen the use of this menu system to determine the price based on visual information by a software agent. Therefore, this system is suitable for micro, small and medium industries in the use of P2P servers and is more usable system interface for owners than previous study.