• 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.

• International Journal of High-Rise Buildings
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• v.12 no.1
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• pp.19-33
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• 2023

Air Rights techniques, including floor-area ratio (FAR) transfers, FAR bonuses, and FAR storage, have been widely applied among skyscraper constructions in New York City for profit maximization goals. Since 1916, air rights regulations in New York zoning system have been revised and improved over the years to cater the urban development needs of different periods, and they also result in typical skyscraper block typologies. This research firstly performed spatial overlay analysis to reveal the spatial correlation between skyscraper blocks and air rights application blocks; secondly, Spacematrix parameters and cluster analysis are applied to divide the skyscraper urban block of New York City into four categories. Compared with air rights application data, the research attempts to illustrate how various air rights techniques have acted on the formation and evolution of skyscraper block typologies in the pre-1916, 1916-1961, 1961-2010, and 2010-present periods respectively, in order to reveal the relationship between public policies and urban morphology in a broader sense and also provide references for policy making in future.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.10
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• pp.3-10
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• 2014

In this paper, the performances of the presented D2D (device-to-device) systems under the environment of the cognitive convergent overlay networks are evaluated based upon the locations of the D2D users' terminals, the power consumptions of the terminals and the reductions of the interference levels. As the capabilities of the users' terminals improve, the optimization of the system is crucial to the efficient utilization of the radio resources of the individual networks considering their mobility and the features of their networks. Users' mobility model is given for the performance evaluation of the D2D system. In this paper, the performances of the D2D systems are evaluated in terms of the performance index of the FER (frame error rate) employing multiantenna techniques (MIMO:multiple input multiple output) for the various network environments.

• Economic and Environmental Geology
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• v.29 no.5
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• pp.575-587
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• 1996

The purpose of this study is to develop geostatistical methods for selection of prospective areas of polymetallic nodule deposits in KODOS (Korea Deep Ocean Study) area of the North-East Pacific Ocean. In this study $110{\times}165$ grid system was used, and each node represents the center of an estimated block of $1km{\times}1km$. The ordinary kriging was applied to SeaBeam2000 data in order to evaluate the bathymetry. A structural analysis (variogram) of the bathymetry data was carried out for constructing digital terrain model (DTM) and the maximum slopes of the bathymetry were calculated by DTM data. The above method can be used to solve the problem that is resulted from the lack of theory of a change of support model for the maximum slope of the bathymetry. The ordinary kriging and the indicator kriging were used to evaluate the nodule abundance, and the different two kriging methods were compared to evaluate the accuracy for the estimation of the nodule abundance. It has been shown that indicator kriging was better estimation tool than the ordinary kriging. The overlay map is presented for the selection of potentially minable sites by combining the two indicator maps of the nodule abundance and the maximum slope of bathymetry. This overlay map could be utilized to establish follow-up survey and to investigate the potentially minable sites in the KODOS area.

• Journal of Welding and Joining
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• v.2 no.1
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• pp.4-17
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• 1984

Overlaid weld metals of austenitic stainless steel in a pressure vessel of power reactor are usually post-weld heated for a long period of time after welding. The PWHT is considered as a kind of sensitizing and it is important to check the soundness of the weld metal after PWHT, especially about the precipitation of carbides. The purpose of this report is to obtain information on the relation between the change of microstructure and Post-Weld Heat Treatment in the overlaid weld metals. Metallurgical aspects of the problem on austenitic stainless steel heated at $625^{\circ}C$, $670^{\circ}C$, $720^{\circ}C$ and $760^{\circ}C$ for 3, 10, 30, 100 and 300 hours have been investigated by means of optical-micrography, micro-hardness measurement, scanning electron microscope and electron-probe micro analysis. From the results obtained, the following conclusions are drawn; 1) The PWHT above $625^{\circ}C$ for a long time causes a diffusion of carbon atoms from low alloy steel into stainless steel, and consequently carbon is highly concentrated at the boundary layer of stainless steel. 2) C in ferritic steel migrated to austenitic steel and carbides precipitated in austenitic steel along fusion line. At higher temperatures, the ferrite grains coarsened in the decarburized zone. 3) In the change of microstructure of stainless steel overlaid weld metal, the width of carbides precipitated zone and decarburized zone increased with increase of PWHT temperature and time. 4) At about $625^{\circ}C$ to $760^{\circ}C$, chromium carbides, mainly $M_{23} C_6$, precipitate very closely in the carburized layer with remarkable hardening. 5) Precipitation of delta ferrite from molten weld metal depends on solidification phenomenon. There was a small of ferrite near the bond in which the local solidification time was short, comparing with after parts of weld metal. Shape and amount of ferrite were not changed by Post-Weld Heat Treatment after solidification.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.3
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• pp.83-89
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• 2010

Scalable routing is one of the key challenges in designing and operating large scale MANETs. Performance of routing protocols proposed so far is only guaranteed under various limitation, i.e., dependent of the number of nodes in the network or needs the location information of destination node. Due to the dependency to the number of nodes in the network, as the number of nodes increases the performance of previous routing protocols degrade dramatically. We propose Cluster Overlay Dynamic Source Routing (CODSR) protocol. We conduct performance analysis by means of computer simulation under various conditions - diameter scaling and density scaling. Developed algorithm outperforms the DSR algorithm, e.g., more than 90% improvement as for the normalized routing load. Operation of CODSR is very simple and we show that the message and time complexity of CODSR is independent of the number of nodes in the network which makes CODSR highly scalable.

• Journal of the Korea Safety Management & Science
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• v.12 no.1
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• pp.35-42
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• 2010

Due to the industrialization and urbanization, the transport of hazardous materials increases, which rises possibilities in occurring prospective accidents in terms of hazardous material transport as well. This study applied the model developed from the previous research to analyze the scale of damage areas from the accidents related to hazardous material accidents, as well as suggested a method to measure automatically the scale of accident including casualties and environmental damage based on the guideline which suggests the quantities of hazardous materials exposed from an accident and was defined in the study of standardization for hazardous material classification. A buffering analysis technique of Geographic Information System (GIS) was applied for that. To apply the model which evaluates the scale of population and exposure to environment on each link, rail network, zones, rail accident data, rail freight trips, and locations of rivers etc were complied as a database for GIS analysis. In conclusion, a method to measure damage areas by the types of hazardous materials was introduced using a Clip and a Special Join technique for overlay analysis.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.1
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• pp.11-18
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• 2018

Two-dimensional (2D) materials such as transition metal dichalcogenides have attracted tremendous scientific interests owing to their potential of solving the zero band-gap issue of graphene. In this work, the research areas and technology evolutionary dynamics of the 2D materials were identified using the scientometric method focusing on keyword mapping and clustering. The time-series analysis showed that the technological progress of 2D material is in the early growth period. The overlay mapping analysis were carried out to investigate the technology evolution of 2D materials with time. The strategic diagram of co-word analysis classifying the topological positions of keyword was derived to support the analysis results. It is conjectured that extensive research will be conducted widely on the application of 2D materials not only in electronic and optoelectronic devices, but also in various other fields such as biomedical applications, and that their development will be more rapid based on accumulated results of extant graphene research.

• The Journal of Pediatrics of Korean Medicine
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• v.38 no.1
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• pp.10-22
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• 2024

Objectives This bibliometric analysis aimed to determine the status of pediatric acupuncture research. Methods Relevant bibliographic information up to January 9, 2024, was collected through searches in the Web of Science Core Collection. Bibliographic information was preprocessed for data analysis and analyzed using VOSviewer software. Network maps of the authors and their affiliated institutions in the included studies were constructed and visualized, and clusters for each major node were identified. In addition, the latest research keywords were visualized using an overlay visualization function. Results The field of pediatric acupuncture research has shown a 20.5-fold quantitative increase in the number of publications over the past 30 years (1991 - 2023). In the field of pediatric acupuncture research, the United States has the highest productivity and influence, and South Korea ranked 7th in productivity and 10th in influence. Through keyword analysis in the field of pediatric acupuncture research, four clusters were identified. Pain management, use in pediatric oncology, and use in postoperative management were identified as important clinical topics. There is a lack of exchange among researchers in the field of pediatric acupuncture. Conclusions Pediatric acupuncture research continues to show quantitative growth and western countries have shown high productivity and influence in this field. In this study, the major keywords in the field of pediatric acupuncture research were identified, and the results can be used to establish the research direction of the Korean medicine community.

• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.4
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• pp.165-175
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• 2005

Geographic Information System(GIS) is useful to preserve cultural heritage and land use management using both spatial information management technique and spatial analysis function in cultural heritage management. The purpose of this study is to build a database of pottery and kiln sites in South Korea, to analyze site locations and finally to make prediction model. The locations of 1,200 sites are put into GIS database. Such factor elevation, slope angle, aspect, horizontal/vertical distance from the nearest water are analyzed. Each factor was statistically analyzed on GIS and represented to rank 1-5. Pottery/kiln can be predicted by the spatial analysis function in overlay methods. As a result of this study, preliminary application of prediction model shows that the high potential area is between the slope and alluvial plain. Field survey in the Sungbuk-dong in Daejeon city supports the preliminary result. More data can make improve efficient prediction model in unknown areas.