• Environmental Analysis Health and Toxicology
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• v.25 no.3
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• pp.181-186
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• 2010

Perfluorinated Compounds (PFCs) are anthropogenic compounds found in trace amounts in many environmental compartments far from areas of production. Along with the highly persistent nature of PFCs, there are increasing concerns over the potential adverse effects of them on the ecosystems. Most of highly fluorinated compounds degrade into PFOS and PFOA that are very stable compounds hard to break down. So, in this study, we tried to determine the toxicity of PFOS and PFOA in the terrestrial invertebrate. Acute toxicity test using earthworm, Eisenia fetida, was performed according to the OECD test guideline 207 (Earthworm, Acute Toxicity Tests). In the 14 day acute toxicity tests, the highest concentration causing no mortality and the lowest concentration causing 100% mortality of PFOS were 160 and 655 mg/kg (dry weight), respectively. And the highest concentration causing no mortality and the lowest concentration causing 100% mortality were 500 and 1,690 mg/kg (dry weight), respectively in the PFOA-exposure group. 14 day-LC50 values were estimated at the level of 365 and 1,000 mg/kg (dry weight) in the PFOS and PFOA-exposed group. These results indicate that under laboratory conditions PFOS is about 3 times more toxic to earthworms than PFOA. Based on known environmental concentrations of PFOS in the soil of Korea, which occur in the 0.42~0.73 ng/L range, there is no apparent risk to terrestrial invertebrate, earthworms. However, further work is required to investigate long-term effects on these and other terrestrial organisms.

• Analytical Science and Technology
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• v.15 no.6
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• pp.529-533
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• 2002

The separation and determination method of racemic isomers of flurbiprofen in urine samples have been investigated using column switching- HPLC, which include the sample treatment and concentration column. The optical rotation of two isomers separated were measured to identify d-form and l-form. The calibration curves are liear in the ranges of $0.11-5.4{\mu}g/mL$ for both d-form and l-form. The detection limits were $0.031{\mu}g/mL$ for l-isomes and $0.027{\mu}g/mL$ for d-isomer. The coefficients of variation of intra-day and inter-day precision of this method were about 1.8%. The present method was apllied to determine the concentration of racemic isomers in urine sample from human eating the drug.

• Analytical Science and Technology
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• v.10 no.1
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• pp.35-42
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• 1997

The sample pretreatment technique using a high pressure acid digestion bomb for the analysis of ceramic capacitor materials, such as barium titanate and PZT, was studied. When the concentrations of hydrochloric acid were varied with the addition of nitric acid or distilled water, quantitative measurements for those samples were carried out using inductively coupled plasma atomic emission spectrometry. From this experiment the results indicate that most of elements, such as Ba, Mn, Zn, Si, etc., aren't affected by the concentration of hydrochloric acid but Nb and Zr are very susceptable to it. It however turns out that the digestion time relatively gave little effects on the analytical result. In case of Nb the ratio of hydrochloric acid to water should be greater than 3:1(v / v) for the best analytical result. For the Pb determination use of diluted hydrochloric acid compared to the mixture of nitric acid and hydrochloric acid showed a better analytical result.

• Journal of Astronomy and Space Sciences
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• v.30 no.4
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• pp.223-230
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• 2013

Sudden enhancements of daytime NmF2 appeared in Anyang ionosonde data during summer seasons in 2006-2007. In order to investigate the causes of this unusual enhancement, we compared Anyang NmF2's with the total electron contents (GPS TECs) observed at Daejeon, and also with ionosonde data at at mid-latitude stations. First, we found no similar increase in Daejeon GPS TEC when the sudden enhancements of Anyang NmF2 occurred. Second, we investigated NmF2's observed at other ionosonde stations that use the same ionosonde model and auto-scaling program as the Anyang ionosonde. We found similar enhancements of NmF2 at these ionosonde stations. Moreover, the analysis of ionograms from Athens and Rome showed that there were sporadic-E layers with high electron density during the enhancements in NmF2. The auto-scaling program (ARTIST 4.5) used seems to recognize sporadic-E layer echoes as a F2 layer trace, resulting in the erroneous critical frequency of F2 layer (foF2). Other versions of the ARTIST scaling program also seem to produce similar erroneous results. Therefore we conclude that the sudden enhancements of NmF2 in Anyang data were due to the misrecognition of sporadic-E echoes as a F-layer by the auto-scaling program. We also noticed that although the scaling program flagged confidence level (C-level) of an ionogram as uncertain when a sporadic-E layer occurs, it still automatically computed erroneous foF2's. Therefore one should check the confidence level before using long term ionosonde data that were produced by an auto-scaling program.

• Smart Media Journal
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• v.5 no.3
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• pp.62-66
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• 2016

The recent increase in virtual reality (VR) technology around the world has been VR work in cooperation with technology from other sectors to form new trends. In the case of advertising, it is difficult to trace if VR users viewed a certain piece of advertisement because the current technology does not allow them to interact with the screen. Eye tracking technology can act as a solution to the problem of tracing advertisement views as it allows for data extraction in relation to which advertisements were viewed and for how long. The research paper suggests a method of how to track the eyes of users in VR advertising. The suggested method includes communication between a server and VR HMD (virtual reality head mounted display) as well as a screen of output from the server.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.12
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• pp.2875-2882
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• 2013

The design of PN(Pseudo Noise) sequences with good cross-correlation properties is important for many research areas in communication systems. Also analyses of cross-correlation frequency between designed sequences have been researched. In this paper we analyze of cross-correlation distribution and properties of non-linear binary sequences family $S^r=\{Tr^m_1\{[Tr^n_m(a{\alpha}^t+{\alpha}^{dt}]^r\}{\mid}a{\in}GF(2^m),0{\leq}t < 2^n-1\}$, where $gcd(r,2^m-1)=1$ with 5-valued cross-correlation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.5
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• pp.1138-1144
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• 2013

Cross-correlation functions of maximal period sequences have been studied for decades. In this paper, we find the cross-correlation values of non-linear sequences $S_a^r(t)=Tr_1^m\{[Tr_m^n(a{\alpha}^t+{\alpha}^{dt})]^r\}$ having the maximal period $2^n-1$ for Niho type decimation $d=2^{m-2}(2^m+3)$, where n=2m. In particular, we call d Niho type decimation in case $d{\equiv}1(mod\;2^m-1)$. And we analyze the cross-correlation distributions of $S_a^r(t)$ when the phase shift ${\tau}=(2^m+1)k(0{\leq}k{\leq}2^m-2)$ and provide experiment results.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.12
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• pp.491-498
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• 2016

Recently leakages of confidential information and internal date have been steadily increasing by using booting technique on portable OS such as Windows PE stored in portable storage devices (USB or CD/DVD etc). This method allows to bypass security software such as USB security or media control solution installed in the target PC, to extract data or insert malicious code by mounting the PC's storage devices after booting up the portable OS. Also this booting method doesn't record a log file such as traces of removable storage devices. Thus it is difficult to identify whether the data are leaked and use trace-back technique. In this paper is to propose method to help facilitate the process of digital forensic investigation or audit of a company by collecting and analyzing BIOS firmware images that record data relating to BIOS settings in flash memory and finding traces of portable storage devices that can be regarded as abnormal events.

• The KIPS Transactions:PartA
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• v.9A no.4
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• pp.563-572
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• 2002

A performance monitor is indispensable to trace and evaluate performance of a program under distributed processing environment. A performance monitor il classified as off-line and on-line according to its output method. An off-line performance monitor analyzes its performance after a program terminates, and an on-line performance monitor analyzes its one while a program runs. Therefore, the on-line function is essential to analyzing and debugging the program fast. JaNeC, distributed processing environment that is implemented in Java, contains an off-line performance monitor for this. However, this performance monitor may not analyze the program running on JaNeC efficiently. Consequently, this paper explains that an on-line performance monitor is designed and implemented for fast analysis and debugging of the program running on JaNeC. This on-line performance monitor is designed to minimize effects on a program to analyze, and provides various forms of graphic output, to analyze the program effectively. In addition, even after a program terminates, it provides interface with the off-line performance monitor, to analyze again.

• Resources Recycling
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• v.10 no.4
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• pp.34-41
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• 2001

A research was performed to evaluate a use of shredder residue to currently dispose of at landfills. Laboratory analyses were conducted to determine especially the fuel characteristics of shredder residue. For this aim, shredder residue was classified by the particle size as well as by the type of material and the content of Cl, S, ash, and calorific value were determined. Due to the chlorinated plastic content of shredder residue, mean concentration of Cl was found to exceed 4wt% except one sample while that of S was ranged from 0.25 to 0.39 wt%. As far as calorific value was concemed, plastic was observed to be more than 10,000 kcal/kg while wood/paper and fiber accounted for approximately 4,000 kcal/kg. Shredder residue was found to contain varying trace amounts of metal elements, including Fe of 6∼8.5 wt%. Hg and Cr(VI) were not detected, however, while Cd was contained as small as 0.0004-0.0009 wt%.