• The Journal of the Korea Contents Association
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• v.15 no.12
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• pp.35-49
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• 2015

Recently, with the development of wireless communication technologies and mobile equipments, various studies on mobile P2P networks have been conducted. In this paper, we propose an advertisement dissemination method considering peer's mobilities and preferences in mobile P2P networks. The proposed scheme generates a peer's preference through the analysis of users' activities to disseminate advertisements with user preferences. To reduce duplicated advertising messages and improve reception ratio, the priority of advertisement re-dissemination is determined according to peer's preferences, mobilities, and advertisement reception ratio. We improve the participation rate of the advertisement dissemination of mobile peers using the incentive mechanism in mobile P2P networks. To show the superiority of the proposed scheme, we compare it with the existing scheme in terms of the number of messages and accuracy.

• Economic and Environmental Geology
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• v.41 no.6
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• pp.719-729
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• 2008

In this study, the speciation, adsorption, and transport of uranium in groundwater environments were simulated using geochemical models. The retarded transport of uranium by adsortption was effectively simulated using 3-D groundwater flow and reactive transport models. The results showed that most uranium was adsorbed(up to 99.5%) in a neutral pH(5.5$pCO_2(10^{-3.6}atm)$ condition. Under the higher $pCO_2(10^{-2.5}atm)$ condition, however, the pH range where most uranium was absorbed was narrow from 6 to 7. Under very low $pCO_2(10^{-4.5}atm)$ condition, uranium was mostly absorbed in the relatively wide pH range between 5.5 and 8.5. In the model including anion complexes, the uranium adsorption decreased by fluoride complex below the pH of 6. The results of this study showed that uranium transport is strongly affected by hydrochemical conditions such as pH, $pCO_2$, and the kinds and concentrations of anions($Cl^-$, ${SO_4}^{2-}$, $F^-$). Therefore, geochemical models should be used as an important tool to predict the environmental impacts of uranium and other hazardous compounds in many site investigations.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.750-753
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• 2009

최근 유비쿼터스 및 모바일 환경에서 Peer-to-Peer(P2P)시스템에 대한 연구들이 활발히 진행되고 있다. 모바일 환경에서는 모바일 환경의 제약사항과 함께 이동성이라는 특징이 중요하게 고려된다. 노드의 이동에 의해서 네트워크의 주소가 변경되어 P2P 네트워크 망에서 유효하지 않은 접속 정보들이 생기고 이러한 정보들이 검색 및 P2P 시스템의 전체적인 성능을 떨어뜨리게 된다. 이 논문은 이러한 접속 정보들의 불일치를 해결하여 접속 정보를 유지하기 위한 효과적인 방법론인 이동전파 알고리즘을 제안한다. 이 알고리즘은 접속 정보의 불일치를 해결하기 위해 정보를 빠르게 처리해서 P2P 시스템의 성능을 향상하는 것을 목표로 한다. DHT 기반 P2P 시스템을 기반으로 하여 제안하는 알고리즘을 적용하여 실험을 하였으며, 그 결과로 처음 신규 발견된 정보를 재 발견하는 경우에 성능이 기존의 DHT 기반의 P2P 시스템보다 80% 향상되었음을 알 수 있다.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.12
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• pp.81-88
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• 2012

As the performance of the next-generation broadband wireless networks is dramatically enhanced, various services (i.e., education, Live video streaming, Live video conferencing, online games, etc.) have been provided to users through a smart mobile platform. Those services are usually provided by using the centralized communication server. However, since all multimedia traffic is exchanged through a communication server, it often has the scalability problem with regard to traffic management. Our main purpose is for group smart users to provide scalable live multimedia streaming service based on P2P network. To do this, we have designed an architecture of P2P-based service management for mobile group communication management and service management protocol. In order to verify the performance of the proposed scheme, we have mathematically analyzed the performance in terms of the average transmission delay and bandwid th utilization.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.12
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• pp.17-27
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• 2011

Most of the previous mobility management protocols such as IETF MIPv4/6 and its variants standardized by the IETF do not support global seamless handover because they require partially changes of the existing network infrastructure. In this article, we propose a simple mobility management protocol (SMMP) which can support global seamless handover between homogeneous or heterogeneous wireless networks. To do this, the SMMP employs separate location management function as DMMS to support global user and service mobility and the bidirectional tunnels are dynamically constructed to support seamless IP mobility by using the IEEE MIH extension server, which is extended the IEEE 802.21 MIH standards. The detailed architecture and functions of the SMMP have been designed. Finally, the mathematical analysis and the simulation have been done. The performance results show the proposed SMMP outperforms the existing MIPv6 and HMIPv6 in terms of handover latency, packet loss, pear signal noise ratio (PSNR).

• Korean Journal of Weed Science
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• v.18 no.4
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• pp.325-332
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• 1998

This study was carried out to investigate the adsorption and the movement of herbicide fenoxaprop-P-ethyl in the silty clay soil(SiC) and the sandy loam soil(SL). Fifteen percent of the added herbicide was adsorbed within 30 min after shaking, and a quasi-equilibrium was reached after 8 to 14 h. The time required for 50% adsorption was 15.8 h in the SiC and 19.3 h in the SL. The equilibrium adsorption isotherm was followed by the Freundlich equation and the Kd was 3.86 in the SiC and 2.32 in the SL. The herbicide in the soil columns flooded with 3 cm water depth and eluted at 0.8 cm/day was leached to 6 cm and 8 cm depth at 7 and 21 days after the treatment, respectively. However, the movement was widened with increased amount of leaching water. The herbicide in the field soils was moved up to 6 cm and 8 cm depth at 14 and 56 days after the treatment, respectively. However, the large amount of the applied herbicide was distributed in 0~2 cm profile in all of the soils examined. Half-life of the chemical in soils was shorter than 7 days and the time to 90% degradation was about 4 weeks. The results indicate that the herbicide has relatively small mobility and short persistence.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.9
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• pp.18-26
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• 2012

As the performance of the next-generation broadband wireless networks is dramatically enhanced, various services (i.e., education, video conferencing, online games, etc.) have been provided to users through a smart mobile platform. Since those services are usually provided by using the centralized architecture, it is difficult for a lot of users to provide the scalable communication service with regard to traffic management. To solve these problems, we have proposed an architecture of P2P-based group communication management scheme using smart mobile device. More specifically, we design the group management protocol and algorithm for the group member management and the traffic management. By using these methods, the mobile multimedia streaming service can be provided with scalability. In order to verify the performance of the proposed scheme, we have mathematically analyzed the performance in terms of the average transmission delay and bandwidth utilization.

• Korean Journal of Environmental Agriculture
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• v.17 no.4
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• pp.362-367
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• 1998

To investigate the effects of simulated acid rain(SAR) on the downward movement of mineral nutrients, SARs of different pH were applied to the soil. SAR of pH 2.0 decreased the soil pH greatly, while SAR of pH 4.0 and 6.0 did not change the soil pH to compare to that of SAR of pH 2.0. Decrease in soil pH was in the order of sandy loam > loam > clay loam. The amoumt of leached exchangeable and soluble bases from the soil due to the penetration of SAR was in the order of Ca >Mg > K. After application of 1200mm SAR of pH 2.0 in to the soil downward mean movements of the exchangeable and soluble bases was in the order of Mg > Ca > K in sandy loam and loam soil and Ca > Mg > K in clay loam soil. Downward movements of the those bases under pH 4.0 into the soil was in the order of Mg > K > Ca in sandy loam and clay loam, and K > Mg > Ca in loam soil. Available phosphorus moved slightly downward with increasing acidity of the SAR.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.5
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• pp.19-28
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• 2012

Recently a grid and cloud computing collaboration have become a social issue. These collaborative network system, the P2P system based on this system. Distingui shed from the client/server systems, P2P systems in order to exchange information, its purpose and functions are divided according to the morphological Category. In accordance with the purposes and functions of information and data retrieval, remote program control and integration services for the offers. Most P2P systems client/server scalability, and management takes the form, but to overcome the disadvantages in terms of applying the mixed-mode system is increasing. And recently the distributed computing aspects of the service to users in order to provide suitable to accommodate the diverse needs of various types of mobile agent technology is needed. In this paper, as required by the mobile agent access to a remote resource access control and agent for the execution and management capabilities and improve the reliability of the mobile agent system designed to suggest.

• The KIPS Transactions:PartD
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• v.10D no.2
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• pp.327-336
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• 2003

Recently the rapid growth of Internet and the construction of high speed networks make many kinds of multimedia services possible. But most of current multimedia services are designed being by client/server model, which incurs high load of central server. In order to solve this problem, we propose a peer-to-peer network-based discovery mechanism for multimedia services. In the proposed scheme, mobile agents that have autonomy and mobility are used to search the location of resources. Use of mobile agents can solve the loss problem of the search result that occurs when the network is unsettled in pure peer-to-peer network. It also supports interoperability in heterogeneous system environments. In the proposed scheme, each host maintains the location information of resources which are locally requested or recently requested by other hosts. So, the proposed scheme has faster response time than the pre-existing mechanisms in pure peer-to-peer network environments.