• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11A
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• pp.1092-1100
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• 2006

In this paper, we propose a full rate quasi-orthogonal space-time-frequency block coded orthogonal frequency division multiplexing(QOSTF-OFDM) that can achieve full symbol rate with four transmit antennas. Sincr: the proposed QOSTF-OFDM can not achieve full diversity, we use diversity advantage collection with zero forcing (DAC-ZF) decoder to compensate the diversity loss at receive side. At the same frequency efficiency, compared with linear orthogonal space-time codes which can not achieve full rate with four transmit antennas over complex constellations, low level modulation can be employed by proposed scheme due to its full rate, i.e., modulation advantage can be achieved. Due to modulation advantage and collected diversify advantage, the proposed scheme exhibits better BER performance than other orthogonal schemes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.1
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• pp.42-50
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• 2016

Recently, researches about the communication between LED array and the camera (alias 'Visual-MIMO'), have been actively conducted, and the application to the vehicle and a smart phone is expected to be maximized. Since the bit error may occur if the ISI is severe in a LED array, it is necessary to switch from the multiplexing to the diversity mode. In this paper, according to the use or not of a reference array pattern, a method for determining the transition time to the diversity mode is suggested and verified. When using the reference pattern, it determines the transition time to the diversity mode from the multiplexing using the brightness information of the received image. If the reference array pattern is not used, the size of LED array compared to the entire image according to the distance is used and the size of the LED array at the distance of a severe ISI may be used for the determination of transition time to the diversity. Finally, the proposed method is verified through the simulation and hardware experiments as well as by analyzing the performance in accordance with the ISI level and the distance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37A no.12
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• pp.1023-1030
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• 2012

The diversity techniques can benefit underwater acoustic communications when the distance between sensors is sufficiently apart, and this leads to the increases in the physical size of the communication system: thus it is very hard to practically use such systems in real-environments. Therefore, in this paper, we have collected data from real underwater cannel environments in order to analyze the usability of diversity combined with beamforming techniques. And we have estimated the fading characteristics from the measurement data, and analyzed the correlation coefficients using the estimated fading characteristics. After analyzing the estimated fading characteristics from the measurements data, we found out that by applying diversity techniques on the output signals from beamformers that perform beamforming from different multipath directions, we can reduce the distance between sensors and at the same time benefit from the diversity gain.

• Journal of the Korea Convergence Society
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• v.11 no.7
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• pp.309-317
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• 2020

The purpose of this study was conducted in two stages for university students at K and Y universities in Gyeongsangbuk-do to examine the factors affecting their use intention to use YouTube learning contents due to any of the factors of YouTube learning contents characteristics. Based on the results of the first survey, the measurement items were organized and based on this, second survey was conducted on the use intention of YouTube learning content learners. As a result, it was found that content diversity, content simplicity, content quality, interactivity, and ease of use influenced use intention. Among them, content diversity was found to have the most influence on use intention than others. This study is expected to be used as a basic research data necessary to activate e-learning in the current university and to enhance the learning effect by researching YouTube which is a new learning trend of university students.

• Journal of Microbiology and Biotechnology
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• v.24 no.11
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• pp.1473-1483
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• 2014

Reports of herbicide resistance events are proliferating worldwide, leading to new cultivation strategies using combinations of pre-emergence and post-emergence herbicides. We analyzed the impact during a one-year cultivation cycle of several herbicide combinations on the rhizobacterial community of glyphosate-tolerant Bt-maize and compared them to those of the untreated or glyphosate-treated soils. Samples were analyzed using pyrosequencing of the V6 hypervariable region of the 16S rRNA gene. The sequences obtained were subjected to taxonomic, taxonomy-independent, and phylogeny-based diversity studies, followed by a statistical analysis using principal components analysis and hierarchical clustering with jackknife statistical validation. The resilience of the microbial communities was analyzed by comparing their relative composition at the end of the cultivation cycle. The bacterial communites from soil subjected to a combined treatment with mesotrione plus s-metolachlor followed by glyphosate were not statistically different from those treated with glyphosate or the untreated ones. The use of acetochlor plus terbuthylazine followed by glyphosate, and the use of aclonifen plus isoxaflutole followed by mesotrione clearly affected the resilience of their corresponding bacterial communities. The treatment with pethoxamid followed by glyphosate resulted in an intermediate effect. The use of glyphosate alone seems to be the less aggressive one for bacterial communities. Should a combined treatment be needed, the combination of mesotrione and s-metolachlor shows the next best final resilience. Our results show the relevance of comparative rhizobacterial community studies when novel combined herbicide treatments are deemed necessary to control weed growth.

• 한국IT서비스학회:학술대회논문집
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• 2008.11a
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• pp.153-156
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• 2008

In recent years, IPTV attracts great attention along with the digital convergence of communication and media technologies. IPTV combines the advantages of TV and Internet and changes our lifestyle dramatically. In addition, the IPTV service is capable of becoming a new business model which has huge growth potentials in technology-converging marketplaces. This study examines critical factors on the consumer's adoption of the IPTV service. Based on the Innovation Diffusion Theory (IDT), IPTV specific attributes and personal characteristics, we derive eight key factors in the research model. compatibility, ease of use, image, diversity of contents, interactivity, monetary value, social influence, and user satisfaction. Using the partial least square (PLS) method on the data collected through a web-based survey, we test our research model with several hypotheses. From this study, we find that diversity of contents, compatibility and interactivity have a significant indirect effect on the use of IPTV service via user satisfaction, and user satisfaction and social influence also have a significant direct impact on the IPTV use. These findings not only provide practical insights on the consumer acceptance of new technology-converging services, but also help managers to plan their marketing strategies better.

• Korean Journal of Environmental Biology
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• v.22 no.2
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• pp.259-264
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• 2004

Convention on Biological Diversity has authorized national sovereignty over biological resources so that legislative framework should be established. In biological resources management, the access to biological resources and the benefit sharing arising out of their utilization are two most important steps. Bonn guidelines adopted by the 6th COP of the Convention on Biological Diversity contain MAT (Mutually Agreed Terms) and PIC (Prior Informed Consent) indispensable to implement the access and benefit-sharing process. MAT is contractual agreement between provider countries and use entities while PIC is a specific measure associated with consent prior to access to biological resources. Moreover, the guidelines include the responsibilities of national focal point and competent national authority, incentives and so on. Our laws related to access to biological resources have no items on benefit-sharing and intellectual property rights. The role of the competent national authority is very important to coordinate the organization controlling information availability, opening to the public, and intellectual property rights with other stakeholders. But, the national regulations must not interfere with academic studies on biological diversity and disobey the two objectives of the Convention on Biological Diversity, the conservation of biological diversity and its sustainable use.

• International Journal of Highway Engineering
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• v.13 no.4
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• pp.211-220
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• 2011

TOD(Transit Oriented Development) has recently been active, which presents that TOD planning elements should be comprehensively taken into consideration in order to enhance domestic transit ridership by changing environments in rail station areas and an empirical analysis on the type of rail station areas and transportation demand should be a prerequisite for usage of future development planning. This study aims to grasp a variety of TOD of influence factors in Seoul rail station area and to perform analysis to identify relationship between public transportation demand and these TOD design factors. To make it come true, we gathered data with respect to Density, Diversity, and Accessibility as representative TOD planning elements and carried out factorial and regression analysis. Consequently, we drew 7 influence factors base on factorial analysis: Factor 1(Diversity/ -Use Mix(LUM)), Factor 2(Density/development density), Factor 3(Accessibility/public transportation facility supply), Factor 4(Design/street design), Factor 5(Green/access mode (pedestrian, bike), Factor 6(Design/subway size), Factor 7(Accessibility/Public transit operation) As the result of model development by using factorial and regression analysis, positive influence factors on passenger flow in rail station area are Factor 1(Diversity : Land-Use Mix), Factor 3(Accessibility : public transportation facility supply), Factor 2(Density : development density), Factor 5(Design/ access mode) and Factor 6(subway size) Next, negative influence factor on passenger flow in rail station area shows Factor 7(Accessibility/Public transit operation) as the most influential factor. This is because the growth of service interval of linked subway and bus leads to reduced demand.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.335-340
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• 2005

In many urban cities, mixed-use development is becoming increasingly essential for the creation of an attractive and sustainable environment that promotes economic vitality, social equity and environmental quality. Due to the differences in scale, scope and intent, certain aspects within the project delivery process of mixed-use are not the same as "conventional" single-use projects. The objective of this paper is to highlight these aspects. Two cases in Southeast Asia serve to illustrate the uniqueness and challenges of mixed-use. In conclusion, the differences between mixed-use and single-use are evident in terms of the diversity of team members, the necessity of multiple market analyses, and a multi-layer (versus single-source) financing structure. Finally, issues concerning ownership tangles, land assembly, planning and application procedures, investment criteria of institutions have been identified as major pitfalls.

• Journal of Digital Convergence
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• v.14 no.3
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• pp.63-69
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• 2016

One of the biggest recent issues in the communication market is the explosive distribution of smartphones. One of the reasons why a smartphone could have seen this rapid distribution in terms of the service management is because it enables the access to the Internet without getting restricted by place and time through customization by a user, unlike a feature phone which only has the existing functions mounted on that were already chosen by a suppler. The other reason is because of its applications. This study aimed to make an empirical investigation of the impact of each of the different convenience types of mobile applications on the usage and the use diversity, consider the process of use diffusion, and find out whether there is a difference in the effect of each convenience type on the use-diffusion. According to the findings of this study, it was firstly shown that the effect of each convenience type on the use-diffusion is different, and secondly, it appeared that the more various functions of the mobile applications are used, the more usage increases.