• IEMEK Journal of Embedded Systems and Applications
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• v.6 no.4
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• pp.249-254
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• 2011

A user desktop service can be made available on internet or local area network with the help of virtualization and cloud technologies. The service is usually called a virtual desktop or a desktop cloud. However, a user interface is limited to I/O capabilities of a user's mobile terminal. In order to enhance a user interface on a remote virtual desktop, it is important to connect full-featured I/O devices which are founded locally. Our previous work called SoD (System-on- Demand) has proposed a technique to associate local full-featured I/O devices with a remote virtual desktop in Xen. On the technique, it is required to install a SoD client agent in a user's mobile terminal for connecting a remote virtual desktop. In this paper, we propose a new framework called Web-SoD that does not require any explicit installation to make SoD service available. The SoD client agent is provided by the web technology so that the agent can be installed transparently, and the platform independency is also achieved. Due to insufficient network socket performance of current web technologies, we extend Native Client (NaCl) proposed by Google to support a network functionality by modifying a NaCl library and a service runtime. With conducted experiment, we show that the network extension supports a full socket functionality over the compromised overhead on the web environment.

• Journal of Environmental Science International
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• v.20 no.10
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• pp.1221-1232
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• 2011

We investigated the toxic effects of difenoconazole on the development in the African clawed frog, Xenopus laevis. To test the toxic effects, frog embryo teratogenesis assays using Xenopus were performed. Embryos were exposed to various concentrations of difenoconazole (0-30 ${\mu}M$). $LC_{100}$ for difenoconazole was 30 ${\mu}M$, and the $LC_{50}$ determined by probit analysis was 27.19 ${\mu}M$. Exposure to difenoconazole concentrations ${\geq}$5 ${\mu}M$ resulted in 10 different types of severe external malformation. Histological examinations revealed dysplasia of the eye, heart, liver, somatic muscle, and swelling of the pronephric ducts. The tissue-specific toxic effects were investigated with an animal cap assay. Blood cells were normally induced at a high frequency by mSCF and activin A. However, the induction of blood cells was strongly inhibited by the addition of difenoconazole. Electron micrographs of tested embryos showed the degeneration of somatic muscle and the shrinkage of microvilli on pronephric duct. The gene expression of cultivated animal cap explants was investigated by reverse transcriptase-polymerase chain reaction (RT-PCR). It revealed that the expression of the blood-specific marker(${\beta}$-globin II) and muscle-specific marker (XMA) were more strongly inhibited than the neural-specific marker(XEn2) by the addition of difenoconazole.

• Journal of Environmental Science International
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• v.19 no.8
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• pp.1001-1012
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• 2010

We investigated the toxic effects of tebuconazole on development in the African clawed frog, Xenopus laevis. To test the toxic effects, frog embryo teratogenesis assays using Xenopus were performed. Embryos were exposed to various concentrations of tebuconazole($0-100\;{\mu}M$). $LC_{100}$ for tebuconazole was $100\;{\mu}M$, and the $LC_{50}$ determined by probit analysis was $82.35\;{\mu}M$. The exposure to tebuconazole concentrations ${\geq}40\;{\mu}M$ resulted in 11 different types of severe external malformations including gut dysplasia. Histological examinations revealed various dysplasia in the eye, heart, liver, intestine, somatic muscle, and in the pronephric ducts. The tissue-specific toxic effects were investigated with an animal cap assay. Blood cells are generally induced at a high frequency by the combination of mSCF and activin A, however, the induction of blood cells was strongly inhibited by the addition of tebuconazole. Electron micrographs of tested embryos showed many of multivesicular bodies and dysplasia of photo-receptive cell, however, the somatic muscle degeneration was not severe. The gene expression of cultivated animal cap explants was investigated by reverse transcriptase-polymerase chain reaction and revealed that expression of the blood-specific marker, $\beta$ globin II and muscle-specific marker, muscle actin were more strongly inhibited than the neural-specific marker, XEn2.

• The Journal of the Petrological Society of Korea
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• v.2 no.2
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• pp.139-155
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• 1993

We have shown that the volcanic rocks from the northern part of Cheju Island can be divided into high $P_2O_5/K_2O$(HPK) and low $P_3O_5/K_2O$(LPK) groups, each with distinct geochemical characteristics(Park and Kwon, 1993a and b). This study reports mineral compositions for plagioc-lase, olivine, and clinopyroxene in order to see the dependence of mineral chemistry on the whole rock composition, and discusses equilibrium relationships between crystal and liquid. Plagioclase and olivine phenocrysts show no compositional differences for the two rock group. However, $Al^{ⅵ}/Al^{ⅳ}$ ratios of clinopyroxenes suggest that pyroxenes have fractionated at deeper level, and that the LPK group might have fractionated at higher pressure than the HPK group. These are in good agreement with our previous interpretation based on whole rock chemistry(Park and Kwon, 1993a). Although subhedral or euhedral form and homogenous composition for most plagioclase and clinopy-roxene phenocrysts suggest equilibrium relationship with liquid, the uncertainties associated with liquid, the uncertainites associated with equilibrium constant for these minerals do not allow testing equilibium relationship between mineral and liquid on the basis of chemistry. On the other hand, olivine phenocrysts in hawaiites, for which Kd is well known, show distinct nonequilibrium relationship with calculated liquid composi-tions, while those in other rock compositions are in equilibrium from those for other rocks. We report for the first time as far as we know plagioclase xenocryst and pigeonite inclusion in plagioclase, which indicates assimilation process. In conclusion, these mineralogical observations imply that mag-matic processes underneath the Cheju volcano were not simple.

• Smart Media Journal
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• v.5 no.4
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• pp.18-25
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• 2016

Virtualized hardware resources provides efficiency in use and easy of management. Based on the benefits, virtualization techniques are used to build large server clusters and cloud systems. The performance of a virtualized system is significantly affected by the virtual machine scheduler. However, the existing virtual machine scheduler have a problem in that the I/O response is reduced in accordance with the scheduling delay becomes longer. In this paper, we introduce the Loan/Redemption mechanism of a virtual machine scheduler in order to improve the responsiveness to I/O events. The proposed scheme gives additional credits for to virtual machines and classifies the task characteristics of each virtual machine by analyzing the credit consumption pattern. When an I/O event arrives, the scheduling priority of a virtual machine is temporally increased based on the analysis. The evaluation based on the implementation shows that the proposed scheme improves the I/O response 60% and bandwidth of virtual machines 62% compared to those of the existing virtual machine scheduler.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.3
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• pp.567-575
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• 2011

The two most popular virtual machine allocation schemes, both match making and round robin, do consider hardware specifications such as CPU, RAM, and HDD, but not CPU usage, which results in balanced resource distribution, but not in balanced resource usage. Thus, in this paper a new virtual machine allocation scheme considering current CPU usage rate is proposed while retaining even distribution of node resources. In order to evaluate the performance of the proposed scheme, a cloud computing platform composed of three cloud nodes and one front end is implemented. The proposed allocation scheme was compared with both match making and round robin schemes. Experimental results show that the proposed scheme performs better in even distribution of overall CPU usage, which results in efficient load balancing.