• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.3
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• pp.20-24
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• 2006

In this paper, our research efforts and activities for displaying flight simulation graphics on multi-monitors connected to a Linux cluster is introduced. In this pilot system graphics rendering as well as view calculation including LOD implementation for each monitor is peformed on each sub-node computer connected to the monitor rather than using an expensive main server. The Linux cluster is constructed by combining general-purpose desktop computers, and MPI library Is used for communication between sub-nodes. It could be concluded from our experience that it is possible to construct a massive multi-monitor display system by adding to the cluster as many sub-node computers and monitors as possible with economic efficiency.

• Journal of the Semiconductor & Display Technology
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• v.15 no.2
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• pp.20-25
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• 2016

The parallel computer cluster system has been known as the powerful tool to solve a complex physical phenomenon numerically. The numerical analysis of large size of Li-ion battery pack, which has a complex physical phenomenon, requires a large amount of computing time. In this study, the numerical analyses were conducted for comparing the computing efficiency between the single workstation and the parallel cluster system both with multicore CPUs'. The result shows that the parallel cluster system took the time 80 times faster than the single work station for the same battery pack model. The performance of cluster system was increased linearly with more CPU cores being increased.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.7
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• pp.1293-1310
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• 2011

A simple modification of well known Low Energy Adaptive Clustering Hierarchy (LEACH) protocol is proposed to exploit cooperative diversity. Instead of selecting a single cluster-head, we propose M cluster-heads in each cluster to obtain a diversity of order M. The cluster-heads gather data from all the sensor nodes within the cluster using same technique as LEACH. Cluster-heads transmit gathered data cooperatively towards the destination or higher order cluster-head. We propose a code combining based cooperative diversity protocol which is similar to coded cooperation that maximizes the performance of the proposed cooperative LEACH protocol. The implementation of the proposed cooperative strategy is analyzed. We develop the upper bounds on bit error rate (BER) and frame error rate (FER) for our proposal. Space time block codes (STBC) are also a suitable candidate for our proposal. In this paper, we argue that the STBC performs worse than the code combining cooperation.

• International Journal of Contents
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• v.16 no.4
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• pp.39-49
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• 2020

The goal of this research was to understand the patterns of multidimensional engagement in MOOCs. An email with an online survey link was sent to enrollees in an MOOC course. The survey included 35 questions asking about engagement, teaching presence, and learning persistence. The items were validated in the literature, revised for the MOOC setting, reviewed by four professionals in the field of educational technology, and used in the study. A heterogeneous group of 170 individuals gathered through convenience sampling participated in the study. With cluster analysis of the engagement data, three groups were identified: Cluster1, 2, and 3. Cluster 1 scored high on behavioral, emotional, and cognitive engagement. Cluster 2 scored high on behavioral aspects but low on emotional and cognitive engagement. Cluster 3 scored low on behavioral and cognitive engagement but high on emotional aspects. The study addressed cluster-specific learner characteristics and differences in perceived teaching presence and learning persistence. Design strategies pertaining to each cluster were further discussed. These strategies may guide instructors and practitioners in the design and management of MOOCs and should be further validated through future studies.

• Natural Product Sciences
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• v.25 no.2
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• pp.150-156
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• 2019

Conventional extraction of oil and azadirachtin, a botanical insecticide, from Azadirachta indica involves defatting the seeds and leaves using hexane followed by azadirachtin extraction with a polar solvent. In order to simplify the process while maintaining the yield we explored a binary extraction approach using Soxhlet extraction device and hexane and ethanol as non-polar and polar solvents at various ratios and extraction times. The highest oil and azadirachtin yields were obtained at 6 h extraction time using a 50:50 solvent mixture for both neem leaves (44.7 wt%, $720mg_{Aza}/kg_{leaves}$) and seeds (53.5 wt%, $1045mg_{Aza}/kg_{leaves}$), respectively.

• Environmental Engineering Research
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• v.16 no.4
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• pp.227-230
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• 2011

Seawater desalination technology is a complicated and expensive process. Besides salt removal from seawater, thesignificant problem that needs to be solved is boron removal. Boron removal is difficult so it is a considerable challenge for the desalination process. The main technology of this process is reverse osmosis (RO). RO can remove salt and boron more effectively than other technologies. In a conventional seawater desalination process, coagulant is utilized for pre-treatment but it is difficult to remove boron through this stage. In this study, a coagulant called Mineral Cluster was examined for boron removal. Therefore, Mineral Cluster can be considered a potential coagulant for boron removal in seawater desalination technology.

• Journal of agriculture & life science
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• v.46 no.1
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• pp.105-111
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• 2012

This study was conducted to evaluate the influence of fruit setting order by flower cluster on the fruit weight and the soluble solids content for the strawberry of 'Seolhyang' cultivar. The first flower cluster had higher fruit number, fruit weight, soluble solids content and ratio of large fruit compared to the second and third flower cluster. The fruit set on the upper position fruit in the same flower cluster had higher fruit weight and the soluble solids compared to the fruit set on the lower position fruit in the flower cluster. The fruit weight was highly positive correlated with the soluble solids content. The result indicated that the number of fruit set for marketable yield seemed to be 9-10 per the first flower cluster, 6 per the second flower cluster, 4 per the third flower cluster and 3 per the fourth flower cluster in 'Seolhyang' cultivar.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4440-4444
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• 2012

The purpose of the paper is to draw conclusions form the EU's cluster policy for Korean government policy. The paper consists of five chapters. Chapter two develops theoretical underpinnings of clusters. In chapter three are the research methods shown. Chapter four describes the EU policy for clusters. In chapter is drawn a conclusion and policy implications are discussed. Academic contribution of this study is academically analyzed the first time the research of EU Cluster and Policy of the EU Cluster is to enhance the innovative for SMEs technology.

• Journal of Information Technology Applications and Management
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• v.19 no.2
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• pp.117-134
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• 2012

Cluster industries are geographically concentrated and inter-connected by the flow of goods and services, which is stronger than the flow linking them to the rest of the economy. Photonics industries are one of the fastest growing high-tech industries in the world today. Especially, the city of Gwangju(South Korea) industrial cluster, a specialized complex in photonics industry, produced remarkable results in developing high-quality technologies since it launched the cluster program in 2005. Gwangju photonics industrial cluster will be ranked top level of the world photonics industry. In this sense, this study is aimed at proposing a new research model in which corporate performance influence factors of photonics industrial cluster (i.e., business environment, cooperative relationship, and industry-university-research institute partnership) affect absorptive capacity positively, leading to corporate performance eventually. This study developed a research model to explain the Korean photonics industrial cluster effects, and collected 91 survey responses from photonics based company managers in industrial cluster complex. To prove the validity of the proposed research model, PLS analysis is applied with valid 91 questionnaires. By employing PLS technique, the measurement reliability and validity of research variables are tested and the path analysis is conducted to do the hypothesis testing. In brief, the finding of this study suggests that corporate performance influence factors of photonics industrial cluster affect absorptive capacity positively, and corporate performance as well.

• Journal of Microbiology and Biotechnology
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• v.19 no.12
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• pp.1497-1505
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• 2009

The thermophile Bacillus fordii MH602 was screened for stereospecifically hydrolyzing DL-5-substituted hydantoins to L-$\alpha$-amino acids. Since the reaction occurs at higher temperature, the advantages for enhancement of substrate solubility and for racemization of DL-5-substituted hydantoins during the conversion were achieved. The hydantoin metabolism gene cluster from thermophile is firstly reported in this paper. The genes involved in hydantoin utilization (hyu) were isolated on an 8.2-kb DNA fragment by restriction site-dependent PCR, and six ORFs were identified by DNA sequence analysis. The hyu gene cluster contained four genes with novel cluster organization characteristics: the hydantoinase gene hyuH, putative transport protein gene hyuP, hyperprotein gene hyuHP, and L-carbamoylase gene hyuC. The hyuH and hyuC genes were heterogeneously expressed in E. coli. The results indicated that hyuH and hyuC are involved in the conversion of DL-5-substituted hydantoins to an N-carbamyl intermediate that is subsequently converted to L-$\alpha$-amino acids. Hydantoinase and carbamoylase from B. fordii MH602 compared respectively with reported hydantoinase and carbamoylase showed the highest identities of 71% and 39%. The novel cluster organization characteristics and the difference of the key enzymes between thermopile B. fordii MH602 and other mesophiles were presumed to be related to the evolutionary origins of concerned metabolism.