• Journal of KIISE:Information Networking
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• v.37 no.4
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• pp.294-300
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• 2010

In this paper, We analysis of effective coverage extension for Tri-sector cellular systems using Multi-hop Relay based on IEEE802.16j system. In the proposed international standard of IEEE 802.16j MMR (Mobile Multi-hop Relay) use of the omni-directional antenna, 3-sector and 6-sector antenna is considered to Base Station and Relay Station. Omni-directional antenna service can offer as all directions but a throughput decreases due to the signal interference of near Relay Stations. In the directional antenna, cause of an interference with the base station which it arranges an antenna so that a beam can have the direct and does with neighbor Base Station and Relay Station can be reduced interference, therefore the effective throughput is higher than the omni-directional antenna system. But, In case of Base Station and Relay Station use the directional antenna, the efficiency which the directional antenna has the Co-channel interference due to in the different cell by the channel reuse is decreased. In this study, we propose the structure of arranging the Base Station and Relay Station having the directional antenna in the NBTC, WBTC antenna in a multi-tier. It compared and analyzed with the mode that the multi-hop Relay Station has the omni-directional antenna, Relay Station are used the NBTC antenna and the WBTC antenna system also, We analyze a relation between the performance degradation and the cell coverage extension which it follows because the number of hop in the multi-hop Relay Station.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.1046-1057
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• 2017

Country-specific emission factors should be developed and used instead of IPCC defaults to improve national GHG inventories to Tier 2 and above. Since the country-specific emission factors depend on the type of energy source, energy process, and time trend, identifying the value of each energy source is an important part of building an accurate inventory. In this study, calorific value and carbon emission factor for petroleum energy sources on the basis of calorific value conversion standard for energy source, which are notified in Korea, are collected by 2013 and 2016, and calorific value, carbon content and carbon emission factor And a comparative analysis was conducted. In addition, net calorific values and carbon emission factors calculated for each petroleum based energy source are compared with those shown in 2006 IPCC Guideline.

• Journal of the Korean Society of Costume
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• v.66 no.8
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• pp.78-97
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• 2016

The purpose of this study is to develop textile pattern designs by utilizing the prototype of traditional culture extracted from cultural resources in order to establish a specialty strategy for local cultural contents. To achieve this, the study selected the Hyojaemunjado as source of Jeju traditional culture. Jeju's Hyojaemunjado is characterized mainly by the creative and unique formativeness of Jeju's character paintings. Character paintings often contained images related to the characters featured inside characters, or composed stroke with symbolic iconography. The main subjects of Hyojaemunjado were stories that alluded to the Confucian virtues. Therefore, the purpose of this study was to remind people of the real meaning of Shin(truth) by developing textile pattern designs, which borrows the tessellation technique for design, and the dominant characteristic of geometric abstraction. This study used theoretical research and empirical analysis. First, the study did the theatrical research on Hyojaemunjado based on literature and precedent studies, and then analyzed the style of expression and formativeness on the Shin character paintings through real analysis of Jeju's Hyojaemunjado kept in Jeju National University Museum. Second, based on the analysis of the style(three-tier composition) and formativeness of Hyojaemunjado, it analyzed the formativeness of the iconography about Shin, i.e. character types(semi cursive style, square style) drawn according to the symbolic meaning, palace, unknown flower, pheasant, tile fish and constellation. Based on analysis of the iconography, it stylized the motives that became available on the Archimedean tiling of tessellation, and then developed the textile pattern designs by arranging the iconographic motives with Platonic tiling and Semi-tiling. The reason why this study borrowed tessellation was to create various visual effects using the size of angle, symmetry and change and joint with simple figure.

• Journal of the Korean Geosynthetics Society
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• v.4 no.4
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• pp.13-21
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• 2005

This paper presents the results of an investigation on the effects of settlement of foundation on the behavior of geosynthetic-reinforced modular block walls in a tiered arrangement using the finite-element method of numerical analysis. A parametric study was performed by varing the foundation condition and offset distance between the tiers and reinforcement length of the lower and upper tier using varified finite-element model. The finite-element analysis provided relevant information on the mechanical behavior of the wall and interaction mechanism between the upper and lowers that was otherwise difficult to obtain from the limit-equilibrium analysis based current design approaches. Practical implications of the findings obtained from this study to current design approaches are discussed in great detail.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5B
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• pp.741-752
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• 2010

The ability to seamlessly switch between the macro networks and femtocell networks is a key driver for femtocell network deployment. The handover procedures for the integrated femtocell/macrocell networks differ from the existing handovers. Some modifications of existing network and protocol architecture for the integration of femtocell networks with the existing macrocell networks are also essential. These modifications change the signal flow for handover procedures due to different 2-tier cell (macrocell and femtocell) environment. The handover between two networks should be performed with minimum signaling. A frequent and unnecessary handover is another problem for hierarchical femtocell/macrocell network environment that must be minimized. This work studies the details mobility management schemes for small and medium scale femtocell network deployment. To do that, firstly we present two different network architectures for small scale and medium scale WCDMA femtocell deployment. The details handover call flow for these two network architectures and CAC scheme to minimize the unnecessary handovers are proposed for the integrated femtocell/macrocell networks. The numerical analysis for the proposed M/M/N/N queuing scheme and the simulation results of the proposed CAC scheme demonstrate the handover call control performances for femtocell environment.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.11
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• pp.41-48
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• 2001

The exact general bit error rate (TIER) expression of M-ary square quadrature amplitude modulation (QAM) for arbitrary M has not been derived so far. In this paper, a generalized closed-form expression for the BER performance of M-ary square QAM with Gray code bit mapping is derived and analyzed in the presence of additive white Gaussian noise (AWGN) channel. The derivation is based on the consistency of the format in signal constellation o[ Gray coding and it has been derived from the results for M-16, 64, and 256.

• Journal of The Korean Association of Information Education
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• v.7 no.3
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• pp.309-317
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• 2003

Web-Based Education System changed from one side transmission of information to bi-directional information exchange with user. Accordingly, It had been implemented on 3-tier models with each function separation using database and server side language such as CGI (Common Gateway Interface). But, The CBSD(Component Based Software Development) techniques receives many interests recently, and efforts to apply this are appearing. Thus, In this research implemented component base question solving system. For this, I used EJB(Enterprise Java Beans) that is web server component model, and used Petri-Net for typical specification about message flow between components.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.5
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• pp.41-49
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• 2006

Private land within national parks has raised acute questions for impact assessment practitioners as to whether it is ecologically resourceful enough to be conserved or whether it should be removed from national parks and compensated accordingly. The purpose of this study is to provide a framework for spatial decision support through assessing ecological resource of private land within national parks. In order to assess the ecological resource, private land within national parks was analyzed and quantified based upon topography, flora and fauna. National parks, according to the ecological resource assessment, have been divided into three groups : the parks in need of careful attention for conservation; the parks needed to be retained as buffers, and; the parks that can be released to private land. According to the analysis, part of Mountain Joowang is the third-tier land that does not require conservation efforts. This case study intends to help policy-makers decide whether some private land within national parks can be released and, after the release, what should be done to prevent reckless development of the released land.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.6
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• pp.324-333
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• 2004

This paper discusses the development of an educational web-based power flow program for undergraduate students. The interaction between lectures and users can be much enhanced via the web-based programs which result in the student's learning effectiveness on the power flow problem. However the difficulties for developing web-based application programs are that there can be the numerous unspecified users to access the application programs. To overcome the aforementioned multi-users problem and to develope the educational web-based power flow program, we have revised the system architecture, the modeling of application programs, and database which efficiently and effectively manages the complex data sets related to the power flow analysis program. The developed application program is composed of the physical three tiers where the middle tier is logically divided into two kinds of application programs. The divided application programs are interconnected by using the Web-service based on XML (Extended Markup Technology) and HTTP (Hyper Text Transfer Protocol) which make it possible the distributed computing technology Also, this paper describes the method of database modeling to handle effectively when the numerous users change the parameters of the power system to compare the results of the base case.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.22 no.4
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• pp.25-33
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• 2014

As global warming becoming an environmentally serious issue, more attention is drawn to fuel consumption which is the direct source of green house gas emission. The fuel consumption by aircraft operation is not an exception. Motivated by the societal and environmental context, this paper explains a method for estimation of aircraft fuel consumed during their flights as well as the computational process using real flight track data. Applying so-called 'Total Energy Model' along with aircraft specific parameters provided in EUROCONTROL's Base of Aircraft Data (BADA) to aircraft radar track data, we estimate fuel consumption of individual aircraft flown between Gimpo and Jeju airports. We then assess the estimation accuracy by comparing the estimated fuel consumption with the actual one collected from an airline. The computational results are quite encouraging in that the method is able to estimate the actual fuel consumption within ${\pm}6{\sim}11%$ of error margin. The limitations and possible enhancements of the method are also discussed.