• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2522-2524
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• 2004

최근 P2P 시스템에 대한 연구는 매우 활발하게 진행되고 있다. 그 중 P2P 시스템의 자원 공유에 관한 문제는 매우 중요하게 다루어지며, 또한 많은 연구가 진행되고 있다. 본 논문에서는 분산된 컨텐츠 기반의 자원 공유를 위해 각각의 노드들을 계층별로 분류하도록 하였으며, 레이어 별로 차별적인 서비스를 제공하도록 하였다. 시스템의 특징은 다음과 같다. 먼저, 노드를 성능에 따라 레이어 별로 분류하며, 효율적인 자원 공유를 위해 노드들을 그룹화 한다. 클러스터링을 통해 상위 레이어에 속한 노드들과 자원을 공유할 수 있도록 한다.

• Journal of Digital Contents Society
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• v.8 no.3
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• pp.393-401
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• 2007

P2P systems have gained a lot of research interests and popularity over the years and have the capability to unleash and distribute awesome amounts of computing power, storage and bandwidths currently languishing - often underutilized - within corporate enterprises and every Internet connected home in the world. Since there is no central control over resources or devices and no before hand information about the resources or devices, device discovery remains a substantial problem in P2P environment. In this paper, we cover some of the current solutions to this problem and then propose our feed forward neural network (FFNN) based solution for device discovery in mobile P2P environment. We implements feed forward neural network (FFNN) trained with back propagation (BP) algorithm for device discovery and show, how large computation task can be distributed among such devices using agent technology. It also shows the possibility to use our architecture in home networking where devices have less storage capacity.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.2
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• pp.73-86
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• 2015

This study aimed to identify influencing factors such as job environment, job characteristics, and job competency as they are related to newcomer turnover intentions in the construction of landscape architecture, Korea. The results based on statistical analyses are follows as: The turnover experience of newcomers in the field of landscape architecture construction was 54.5%, about 1.6 times higher than in other fields. The influencing factors among newcomer turnover intentions in the construction of landscape architecture were workload(p<0.01), job suitability, and personal relations(p<0.01), while in job autonomy, work conditions, job competency, job identity, job variety, and job compensation were not statistically significant. This study found that key important factors of dependent variables that conceptually explain the influence of turnover intentions among newcomers differed between the construction of landscape architecture and other fields. The most important factors in turnover intention were workload>personal relationship>job suitability among independent factors. This study implied that efforts for improvement are needed in areas of workload, personal relations, and job suitability to mitigate newcomer turnover intentions so as to establish common and personal goals in the field of landscape architecture construction because turnover intention could lead losses in human resources, time, economy, and psychological health. In conclusion, this study suggested the importance of efforts for human resource management to reduce turnover intentions among newcomers in the field of landscape architecture construction.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.6
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• pp.1086-1090
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• 2004

Architecture generation is the first step in the design of software systems. Most of the qualities that the final software system possesses are usually decided at the architecture development stage itself. Thus, if the final system should be usable, testable, secure, high performance, mobile and adaptable, then these qualities or non-functional requirements should be engineered into the architecture itself. In particular, adaptability is emerging as an important attribute required by almost all software systems. The machinery and tools in the remote site surveillance and connects intelligence information machinery and tools at Internet. We need the server which uses different embedded operating system to become private use. With the progress of information-oriented society, many device with advanced technologies invented by many companies. However, the current firmware technologies have many problems to meet such high level of new technologies. In this paper, we have successfully ported linux on an embedded system, which is based on intel Strong ARM SA-1110 processor, then written several network modules for internet-based network devices.

• Journal of the Korea Society of Computer and Information
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• v.26 no.3
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• pp.1-7
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• 2021

In this paper, optimized media data retrieval and transmission based on the Hybrid CDN/P2P architecture and selective storage through user's prediction of requestability enable seamless data transfer to users and reduction of unnecessary traffic. We also propose a new media management method to minimize the possibility of transmission delay and packet loss so that media can be utilized in real time. To this end, we construct each media into logical segments, continuously compute weights for each segment, and determine whether to store segment data based on the calculated weights. We also designate scattered computing nodes on the network as local groups by distance and ensure that storage space is efficiently shared and utilized within those groups. Experiments conducted to verify the efficiency of the proposed technique have shown that the proposed method yields a relatively good performance evaluation compared to the existing methods, which can enable both initial latency reduction and seamless transmission.

• Advances in concrete construction
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• v.11 no.5
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• pp.419-428
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• 2021

The pH of cement-based materials (CBMs) is an important factor for their durability, sustainability, and long service life. Currently, the use of supplementary cementitious materials (SCMs) is becoming mandatory due to economic, environmental, and sustainable issues. There is a decreasing trend in pH of CBMs due to incorporation of SCMs. The determination of numerical values of pH is very important for various low and high volume SCMs blended cement mortars for the better understanding of different defects and durability issues during their service life. In addition, the effect of cement hydration and pozzolanic reaction of SCMs on the pH should be determined at initial and later ages. In this study, the effect of low and high-volume fly ash (FA) and ground granulated ballast furnace slag (GGBFS) cement mortars in different curing conditions on their pH values has been determined. Thermal gravimetric analysis (TGA) was carried out to support the findings from pH measurements. In addition, thermal conductivity (k-value) and strength activity indices of these cement mortars were discussed. The results showed that pH values of all blended cement mortars were less than ordinary Portland cement (OPC) mortar in all curing conditions used. There was a decreasing tendency in pH of all mortars with passage of time. In addition, the pH of cement mortars was not only dependent on the quantity of Ca(OH)₂. The effect of adding SCMs on the pH value of cement mortar should be monitored and measured for both short and long terms.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.5 no.5
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• pp.30-44
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• 2002

This study is conducted to analyze the change of location and soil characteristics effect on the condition of urban forest in Urban Park and Green Open Space The results of this study are as fallows; 1. Soil acidity is indicated pH 3.88 in Sasang park, pH 4.38 in Hwaji park, pH 4.40 in Daeyeon park, pH 4.68 in Sanseong amusement park, pH 5.15 in Molundae amusement park. 2. Species diversity indices of indicated Sasang park 0.9932, Hwaji park 1.1975, Daeyeon park 1.2160, Sanseong amusement park 1.3080, Molundae amusement park 1.3233 is due to location and soil environment in addition to air pollution effects. 3. The vitality of Pinus thunbergii 27.5ER in Sasang park, 24.9ER in Hwaji park, 24.5ER in Daeyeon park, 23.6ER in Sanseong amusement park, 21.0ER in Molundae park. This shows that tree vitality are impacted by location and soil characteristics. On the basis of the result above, vegetation devices are suggested : 1) Robinica pseudo-acacia management, 2) removing the hazard plants; Smilax china, Humulus japonicus, Pueraria thungergiana, 3) improving soil hardness and soil acidity.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.8
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• pp.1783-1789
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• 2004

It is evaluated that there is infinit capability of creating new e business using P2P program. but the research for the method to protect the copyright of digital contents is urgent even for development of the p2p service because the problem of copyright protection for digital contents is not solved. Though this article, it can be induced that reliable contents sharing use to a flow fund by secure settlement architecture, user authentication and contents encryption and then it as the problem of copyright fee is solved, it is able to discontinue which trouble with a creation work for copyright fee and protection it's once again as growth of p2p market, p2p protocal is will be grow into a important protocal of advanced network. In this article, When users send digital contants to each other in internet, we proposed the P2P DRM algorism to offer a security function which using the technology of copyright management to use a AES Algorithm based on PKI.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.4
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• pp.103-109
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• 2008

Many Internet application provide the PKI(public key infrastructure)-based service to provide authentication and message integrity. Several researchers proposed PKI-based p2p network framework. However, in the real world, the use of PKI is not suitable for peer to peer network, because the peer-to-peer network is an open and dynamic network. Moreover, currently there is no nation-to-nation interoperable certificate. In this paper, we designed reliable p2p file sharing application without public key infrastructure. To do this we propose reliable public key distribution mechanism to distribute public key safely without PKI infrastructure for two-tier super-peer architecture. In our system, each peer generates and distributes its public/private key pairs, and the public key is securely distributed without PKI. The proposed mechanism is safe against MITM attack. This mechanism can be applied various P2P applications such as file sharing, IPTV, distributed resource sharing and so on

• Journal of the Korean Institute of Landscape Architecture
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• v.19 no.3
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• pp.41-54
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• 1991

This study was executed to analyze the vegetational landscape structure and administration planning of Younguan Royal Tomb forest by the classification and DCA ordination were applied to the study are in order to classify them into several groups based on environmental variables. Also Younguan Royal Tomb forest comparison of a pair of photographs taken in 1920s and 1990. Sixteen sites were sampled with clumped sampling method in september 1990 and five quadrats were examined in each site. By classification and DCA, the plant community were divided into two groups(A. japonica community, P. densiflora, Quercus acutissima community) by the humus. Pinus densiflora community of actual vegetion covered 15.9%, Alnus japonica 6.5% and Quercus community 65.6% of the total area. And the afforested vegetation of P. koraiensis. P. rigida and Juglans mandshurica covered 13.2%. DCA ordination showed that successional trends of tree species seem to be from P. densiflora, Q. aliena to Q. acutissima in P. densiflora community and from A. japonica community of the upper layer. By the comparison of couple photographs between 1920s and 1990 we can recognize the change of historical landscape composed of P. densiflora community, A. japonaca and those community shall be conserved by the disclimax method, i.e. the broadleaf vegetation in the underlayer in the P. densiflora community should be cleared out. Otherwise the vegetational landscape sructure in Younguan Royal Tomb is successed to progress succession to Q. acutissima landscape.