• Journal of Korean Society on Water Environment
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• v.26 no.6
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• pp.1034-1039
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• 2010

Variation of formation potential of THM (THMFP) by chlorination of humic acid and characteristics of water quality with ${\gamma}$-ray irradiation were investigated, which were divided into two categories by the order of ${\gamma}$-ray irradiation and chlorination in water treatment process. The group A consisted of the ${\gamma}$-ray irradiation followed by chlorination process of humic acid, and the group B consisted of the chlorination followed by ${\gamma}$-ray irradiation process. The pH, ORP, $UV_{254}$, and DOC decreased rapidly with an increase in ${\gamma}$-ray irradiation of 3 kGy. while conductivity was little changed. Maximum degradation ratio of chloroform in THMs of group A was 82%, while that in group B was 69%. No brominated THMs were detected at high irradiation (>3 kGy). We found that group A water treatment process was more effective in lowering the THMFP than that of group B.

• The Journal of Internal Korean Medicine
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• v.22 no.1
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• pp.1-4
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• 2001

Objective : We wanted to examine the differences of symptoms of stroke by seasons and age groups. Methods : We recorded the symptoms of 254 stroke patients for 1 year and statistically analyzed the results. The Chi-Square test was used for the analysis.(p<0.05). Results : There was no difference of symptoms by age, but the symptoms were different by seasons. In spring and autumn, there was a large amount of Hwa. In summer, there was a large amount of Kihuh, and in winter, there was a large amount of Hwa and Dahm. Conclusions : We have concluded that these differences should be considered in the management and the prevention of stroke.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.23 no.2
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• pp.114-122
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• 2013

Objectives: This study was performed in order to investigate by questionnaire the factors affecting the occupational satisfaction of work-environment measurement workers, as well as to suggest fundamental materials for systematic, administrative and economic improvements which are necessary to create a vision for the future. Material and Methods: A structured questionnaire was used at a total of 152 institutions and 1,254 work-environment measurement workers throughout the country from February to September 2012. Responses came from 97 institutions (64%) and 941 work-environment measurement workers (75.1%). The factors affecting the job satisfaction of work-environment measurement workers were statistically evaluated through $x^2$-test and ordinal logistic regression analysis. Results: Major factors affecting the job satisfaction of workers in relation to work-environment measurement were working, financial, and psychological conditions (p<0.05). Conclusions: Considering the results of this study, the improvement of labor conditions should be undertaken because workers engaged in work-environment measurement are fundamental to occupational health.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.1
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• pp.248-254
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• 2011

As the demands of island tourism increasing, the importance of information is considered the key success factor of island tourism. This study suggest the several factors that affecting in island tourism based on the previous studies of tourism research domain. the Important Performance Analysis(IPA) that has much popularity in tourism research is used to evaluate the information characteristic and priority of island tourism in university students of Korea. Based on the result of this study, the information of the natural landscape/scenery and the sightseeing related activity have less priority than the facilities and local foodstuff of the specific island. Considering the aspects and levels of currently serviced island tourism information, differentiated information that including the facilities and local foodstuff of island have reasonable priority for establishing effective and efficient island tourism strategy.

• Proceedings of the Korea Contents Association Conference
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• 2006.05a
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• pp.251-254
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• 2006

The application of reflex media in education has been widely used in the aspects of teaching & learning method, humanitarian education and the culture of school lives. It has been resulted from the generality of the applicable scope within conveying the information, propagation velocity, and the efficiency of the amount of conveyable information through the reflex. To utilize this kind of efficiency of reflex media in producing new graduation culture, I intend to show students the graduate reflex including their 3years' school lives and try to find out its effect from them. And then with this result I have studied the changes of the students behavior in the graduation ceremony. As a result I can notice that the intent of graduation reflex which aims to look back into their past and keep in mind it has been reflected to students. In addition I can ascertain their friendship and love for their school have been lifted while watching the reflex with laugh and cry.

• Journal of the Korean Ceramic Society
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• v.45 no.5
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• pp.263-267
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• 2008

$(Bi_{1/2}Na_{1/2})TiO_3$-based ceramics have been intensively studied as lead-free piezoelectric ceramics. In this study, the piezoelectric properties and phase transition behaviors of BNT based solid solution $(Bi_{0.5}Na_{0.5})_{1-x}Ca_xTiO_3$ ($X=0.01{\sim}0.25$) were investigated. The morphotropic phase boundary(MPB) zone which BNT is transformed from rhombohedral to cubic structure was appeared by adding $CaTiO_3$ with 0.12 mol by the measurement of permittivity and X-ray diffraction. The behavior which ferroelectric BNT with adding $CaTiO_3$ was changed to antiferroelectric and paraelectric state was confirmed by the measurement ofhysterisis loop and depolarization temperature as a function of temperature. As $CaTiO_3$ concentration was increased, the phase transition temperature was decreased. The piezoelectric properties were highest at 0.01 mol of $CaTiO_3$ concentration. The electromechanical coupling factor($K_t$) and mechanical quality factor($Q_m$) were 42% and 254, respectively.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.2
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• pp.245-254
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• 2013

In oriental medicine, it is possible to classify and treat many diseases using the pulse wave detection system. Other problems may arise. As it is a very subjective way to analyze the pulse wave. One problem of the conventional pulse wave detection system is that the arterial pulse sensor is not located correctly at the radial artery. Threrefore measurement results can differ depending on the measurement position and the measurement procedure. This is mostly due to it's sensitivity to high reproducibility. In order to solve this problem this paper proposes an algorithm to analyze the weak pulse wave symptom and strong pulse wave symptom. It uses the portable pulse wave detection system which includes a Hall Sensor. As a final result, it analyzed the weak pulse wave symptom and strong pulse wave symptom by the SPSS statistics technique. It proves that N time (notch point time) and S Amp (rise waveform size) mean values are significantly different in 95% confidence interval.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.6
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• pp.767-774
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• 2005

The DOF (Dissolved Ozone Flotation) system was used to treat the effluent of the secondary wastewater treatment plant. The DOF system uses ozone instead of air, while DAF (Dissolved Air Flotation) uses air. Moreover, since the solubility of ozone is higher than air, the DOF system produces larger volume of micro-bubbles than the DAF system does. Thus, the DOF system performs better than the DAF system in floating ability. The DOF system could remove 70% of turbidity to an average of 0.59NTU in effluent from 2.31NTU in influent. The removal efficiency of absorbance measured with UV-254 in the effluent of the DOF system was 63%, while only 19% was removed by the DAF system. the DOF system removed 84% of the color from 25~26CU to 4CU, while DAF system removed 42% of the color to 15 CU. The CODMn removal efficiency of the DOF system was 34%, 6.8mg/l of effluent $COD_{Mn}$ concentratin, while it was 20%, 8.3mg/L of effluent $COD_{Mn}$ concentratin, to use the DAF system. Microbial bacteria such as coliform bacteria, and heterotrophic bacteria were removed over 99% by the DOF system, and 42~45% by the DAF system. That is, Microbial bacteria were almost completely destroyed by the DOF system. To sum up with, the DOF system was found to be very effective to treat effluent of the wastewater treatment plant.

• Journal of KIISE:Databases
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• v.32 no.3
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• pp.254-262
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• 2005

This paper presents a new sequential indexing method called segment-page indexing (SP-indexing) for multidimensional range queries. The design objectives of SP-indexing are twofold:(1) improving the range query performance of multidimensional indexing methods (MIMs) and (2) providing a compromise between optimal index clustering and the full index reorganization overhead. Although more than ten years of database research has resulted in a great variety of MIMs, most efforts have focused on data-level clustering and there has been less attempt to cluster indexes. As a result, most relevant index nodes are widely scattered on a disk and many random disk accesses are required during the search. SP-indexing avoids such scattering by storing the relevant nodes contiguously in a segment that contains a sequence of contiguous disk pages and improves performance by offering sequential access within a segment. Experimental results demonstrate that SP-indexing improves query performance up to several times compared with traditional MIMs using small disk pages with respect to total elapsed time and it reduces waste of disk bandwidth due to the use of simple large pages.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.06a
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• pp.248-254
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• 2005

This paper presents a quantitative method of sequential separation of $^{90}Sr,\;^{241}Am$ and Pu nuclides with an anion exchange resin and a Sr-Spec resin. The Pu isotopes were purified with an anion exchange resin. The americium and strontium fractions were separated from the matrix elements with an oxalate co-precipitation method. Americium fraction was separated from the strontium fraction with iron co-precipitation method and purified from lanthanides with anion exchange resin. Strontium-90 was purified from other hindrance elements with the Sr-Spec resin after oxalate co-precipitation. The measurement of Pu and Am isotopes was carried out by an ${\alpha}$-spectrometer. Strontium-90 was measured by a liquid scintillation counter. The radiochemical procedure of $^{90}Sr,\;^{241}Am$ and Pu nuclides investigated in this study has been validated by application to IAEA-Reference soils.