• ETRI Journal
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• v.32 no.3
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• pp.464-467
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• 2010

In this letter, we analyze the error performance of a mobile communication system with microdiversity and macrodiversity reception in gamma-shadowed Rician fading channels for a binary differential phase-shift keying modulation scheme. Analytical expressions for the probability density function (PDF) and moment-generating function (MGF) are derived. The average bit error probability can be calculated by averaging the conditional bit error probability over the PDF or using the MGF-based approach. Numerical results are graphically presented to show the effects of macrodiversity, correlation, number of diversity branches, and severity of both fading and shadowing.

• Steel and Composite Structures
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• v.27 no.2
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• pp.177-184
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• 2018

This study contributes to evaluate multiphase topology optimization design of plate-like structures on elastic foundations by using classic plate theory. Multi-material optimal topology and shape are produced as an alternative to provide reasonable material assignments based on stress distributions. Multi-material topology optimization problem is solved through an alternative active-phase algorithm with Gauss-Seidel version as an optimization model of optimality criteria. Stiffness and adjoint sensitivity formulations linked to thin plate potential strain energy are derived in terms of multiphase design variables and Winkler-Pasternak parameters considering elastic foundation to apply to the current topology optimization. Numerical examples verify efficiency and diversity of the present topology optimization method of elastic thin plates depending on multiple materials and Winkler-Pasternak parameters with the same amount of volume fraction and total structural volume.

• Journal of electromagnetic engineering and science
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• v.15 no.1
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• pp.44-52
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• 2015

A worst-case estimate of an envelope correlation coefficient (ECC) is obtained for small multiple-input multiple-output (MIMO) mobile antennas operating below 1 GHz. The worst-case estimate is numerically derived in this paper using spherical and exponential wave functions. The derived result confirms that the worst-case ECC can be easily obtained from the rotation angle between the radiation patterns of two MIMO elements, which are attained directly from the amplitude of 2D electric field patterns without any additional phase and polarization information. As a practical example, MIMO mobile antennas with different antenna element arrangements are compared to verify the validity of the proposed worst-case estimate. Moreover, based on these analyses, we also suggest an effective approach to reduce the ECC of a small MIMO mobile antenna operating below 1 GHz by properly locating the antenna elements to make the radiation patterns perpendicular to each other.

• Land and Housing Review
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• v.8 no.3
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• pp.103-111
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• 2017

This study is aimed to identify the LHI policies in the research process that reflect the diversity of job positions and workplace using a statistical method such as IPA. To collect the sample data questionnaire survey was carried out in 400 staffs in LH including researchers to investigate dissemination of research results and improve factor regard with research. The dissemination of research results is positioned as a important key factor for the determination of research institute policy. From this reason, satisfaction survey was performed for defining the procedure of research system and the dissemination of research findings. The answers give stimulate participation for investigational activity and share some perceptions with research vision a dominant position. Futhermore, select the research theme which is a important association with pending issues at the planning phase is to reinforce the availability of research findings. Lastly, promote research findings intensively is cause availability of research results to increase also.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.1-11
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• 2018

Polymer composites offered broad engineered applications, however their diversity get restricted owing to fluctuations in thermomechanical properties during heating or cooling hence great concern required prior their applications through thermomechanical analysis (TMA). Traditionally, TMA or dilatometry found to be simple, ideal, reliable, sensitive, excellent and basic thermal analytical technique. TMA provides valuable information on thermal expansion, glass transitions temperature (Tg), softening points, composition and phase changes on material of having different geometries simply by applying a constant force as a function of temperature. This compilation highlights the basics and experimental of TMA for both research and technical applications and also provide literature on TMA of polymers, hybrid composites, nanocomposites and their diverse applications.

• 한국벤처창업학회:학술대회논문집
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• 2022.04a
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• pp.129-134
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• 2022

This research investigates the effect of SMEs' digital transformation (DX) efforts in O2O platforms on customer engagement. Among the three DX stages (i.e., digitization, digitalization, and DX), this study focuses on digitalization, a practically viable DX phase for SMEs using O2O platforms. This study categorizes the DX efforts of SMEs into three: information diversity, responsiveness to customers, and the degree of functional use. To analyze the impact of these efforts on customer engagement, we conduct the zero-inflated negative binomial regression using the dataset of Naver Smartplace, one of the representative O2O platforms in South Korea. The analysis result confirms that all three factors have positive impacts on customer engagement. Therefore, this study demonstrates that employing O2O platforms can be an effective strategy for SMEs lacking resources to achieve successful DX.

• Asia pacific journal of information systems
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• v.32 no.3
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• pp.580-600
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• 2022

The purpose of this study is to investigates the effect of SMEs' digital transformation efforts in O2O platforms on customer engagement. This study focuses on digitalization, which is a practically viable phase for SMEs using O2O platforms among the three digital transformation stages (digitization, digitalization, and digital transformation). This study specifically categorizes digital transformation efforts into three categories: information diversity, responsiveness to customers, and the degree of functional use. To analyze the impact of these efforts on customer engagement, we conducted a zero-inflated negative binomial regression using the dataset provided by Naver SmartPlace, a representative O2O platform in South Korea. The results present that the positive relationship between these aforementioned factors and customer engagement. Thus, this study demonstrates that utilizing O2O platforms can be an effective strategy for SMEs that lack the resources to achieve a successful digital transformation.

• The Journal of Fisheries Business Administration
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• v.37 no.2 s.71
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• pp.111-139
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• 2006

Cold storage warehouse industry in Japan has been extended in its scale in terms of both the number of storages and cold storage capacity in order to meet the extended reproduction of the marine products industry. However, increasing total amount of the stored goods since mid 80s led to relative decrease of marine products while the number of storages was remained the same or decreased, though cold storage capacity was gradually increased and is maintained the increase of the average cold storage capacity. As structural change in the cold storage warehouse industry emerges, cold storage warehouses require new approach to individual storage management with 1)diversity of the stored goods; 2) more competition due to increase of the cold storage capacity; and 3) sizing of the average cold storage capacity. Therefore, this study analyzed how cold storage warehouse management activity with individual storage sizing changes; and significance of sizing and functional change in cold storage warehouses experiencing sizing, by observing leading cold storage warehouse industry of the metropolitan area in Japan. In conclusion, reorganization of cold storage warehouse industry in the metropolitan area in Japan can be summarized as follows: First, competition among cold storage warehouses in the metropolitan area in Japan is not simply limited to storage industry but extended to establishment and securing physical distribution function. Second, since cold storage warehouse industry is in Scrap & Build phase, decision of management executives on whether taking direction to maintain/continue enhancement of physical distribution function may cause drastic reorganization in the cold storage warehouse industry, Third, since profit of physical distribution management based on cold storage warehouses is insignificant, it is not easy to accomplish expected management outcome, Fourth, today's cold storage warehouse industry mainly characterized by diversity of the stored goods needs facility reorganization with comprehensive and functional integration covering from F class cold storage capacity to F&C class.

• Journal of Microbiology and Biotechnology
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• v.20 no.1
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• pp.21-29
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• 2010

The phenolic compounds are a major contaminant class often found in industrial wastewaters and the biological treatment is an alternative tool commonly employed for their removal. In this sense, monitoring microbial community dynamics is crucial for a successful wastewater treatment. This work aimed to monitor the structure and activity of the bacterial community during the operation of a laboratory-scale continuous submerged membrane bioreactor (SMBR), using PCR and RT-PCR followed by denaturing gradient gel electrophoresis (DGGE) and 16S rRNA libraries. Multivariate analyses carried out using DGGE profiles showed significant changes in the total and metabolically active dominant community members during the 4-week treatment period, explained mainly by phenol and ammonium input. Gene libraries were assembled using 16S rDNA and 16S rRNA PCR products from the fourth week of treatment. Sequencing and phylogenetic analyses of clones from the 16S rDNA library revealed a high diversity of taxa for the total bacterial community, with predominance of Thauera genus (ca. 50%). On the other hand, a lower diversity was found for metabolically active bacteria, which were mostly represented by members of Betaproteobacteria (Thauera and Comamonas), suggesting that these groups have a relevant role in the phenol degradation during the final phase of the SMBR operation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.5
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• pp.901-911
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• 1994

The error performance of M-ary differential phase shift keying (MDPSK) through m-distribution fading channel in hybrid direct sequence/slow frequency hopped spread spectrum multiple access (DS/SFH-SSMA) systems has been evaluated, and also the error probability has been evaluate when adopting diversity technique and coding technique. From the results, we know that the error performance more deteriorates as depth of fading becomes deeper. In Rayleigh fading environment (m=1), increasing of the number of frequency hopping (q) reduces the effect of multiple access interference, because it decreases the probability a hit. When q is much larger than the number of user (K), the probability of error in high E/N region is dominated by the multipath interference while the multiple access interference is negligible. In lower E/N region, the probability of error is independent of q because the effect of gaussian noise becomes dominat.