• Nuclear Engineering and Technology
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• v.35 no.3
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• pp.251-259
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• 2003

The Taguchi method was applied to investigate the effect of design factors on the performance of the shutdown cooling heat exchanger in the SMART-P. This method provided the simulation matrix for the KDESCENT program and an efficient tool for analyzing the simulation results. Levels of the design factors were selected by the effectiveness-NTU method. From 18 runs with the KDESCENT program, it was found that the performance of the system was greatly influenced by the inlet temperature at the shell side and the mass flow rate of the reactor coolant at the tube side. After applying the Taguchi method, we identified the important design factor that should be controlled and designed carefully. This method provides an efficient way to estimate the influence of each design factor on a system performance.

• KSBB Journal
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• v.15 no.6
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• pp.644-648
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• 2000

Biological fixation of carbon dioxide using microalgae is known as an effective CO$_2$reduction technology. However, many environmental factors influence microalgal productivity. Optimal cultivation factors were determined for the green alga, Euglena gracilis Z, which offers high protein and vitamin E content for animal fodder. In batch culture in a photovioreactor, it was found that theinitial pH, temperature, CO$_2$concentration in air, and light intensity during the optimal cultivating conditions were 3.5, 27$^{\circ}C$, 5-10% and 520 ${\mu}$mol/㎡/s, respectively. When tap water and freshwater were used as cultivating media unsterilized tap water was found to be effective. A kinetic model was considered to determine the relationship between the specific growth rate and the light intensity. The half-velocity coefficient (K(sub)I) in the Monod model under photoautotrophic conditions was 978.9 ${\mu}$mol/㎡/s.

• Proceedings of the KAIS Fall Conference
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• 2001.05a
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• pp.76-78
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• 2001

먹는 물에 존재하는 크립토스포리디움 및 지아디아등 기존의 표준 정수처리 공정에 의해 제거가 용이치 않은 원생동물 둥을 채집할 수 있는 미생물 검출 캡슐을 개발하였다. 본 장치의 여과필터는 고분자물질을 소재로 한 중공사 형태(Hollow Fiber Membrane)로 유효여과면적을 크게하였고, Pore size는 0.1㎛이다. 채집캡슐은 탁도에 따른 투과수량은 일차의 상관관계를 나타내며, 시간당 20ℓ를 투과시킬 때 탁도 7.0 NTU까지 가능함을 확인 할 수 있었다. 일차 시제품은 89.6-94.6%의 크립토스포리디움 및 72.6-78.6%의 지아디아 포낭을 회수하였고, 이차 시제품은 92.5-93.7%의 크립토스포리디움 및 81.3-88.2%의 지아디아 포낭을 회수하는 것으로 나타났다. 동일한 조건에서 외국제품은 84.0%의 크립토스포리디움 및 66.7%의 지아디아 포낭을 회수하는 것으로 나타났다.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.2
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• pp.214-220
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• 2005

Errors may occur due to analysis methods and water quality during the application of the on-line particle counter In water treatment process. Errors caused by analysis methods include particle destruction by shear force due to inflow speed and tube friction, as well as interruption by screening, bubbles and contaminants. Since errors happen frequently because of these factors, it is necessary to examine and evaluate such errors during the application of a particle counter. Errors can be large due to screening and bubbles. Measurement values are effective for water analysis after filtration process. However, because of screening, only measurement values for particles above $7{\mu}m$ are valid for water with a turbidity between 3-10NTU. As particle numbers around $10{\mu}m$ increase a lot after ozone treatment, sufficient pretreatment process is necessary. Physical conditions should keep stable for inflow to decrease errors caused by shear force.

• Food Science and Preservation
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• v.15 no.5
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• pp.617-621
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• 2008

Sequential passes through $Sephadex^{TM}$ columns were used to select phages that displays ligands for dextran ($\alpha$-1,6 linked linear chains) from a phage antibody library. Those phages that bound to the $Sephadex^{TM}$ in each iteration were replicated in E. coli. A phage preparation isolated on the third round selection produced 5.4 nephelos turbidity units (NTU) in a dextran specific immunonephelometric assay, a 2.2 fold higher value than the phage preparation from the first round selection. This phage gave $72\;{\pm}\;10$ normalized intensity (N.I.) in a dip-stick assay against high molecular size dextran (T2000, $2\;{\times}\;10^6) and significantly lower color ($30\;{\pm}\;6$ N.I.) against low molecular size dextran (T10, $10^4$). The presence of an Fab insert in each of these phages was confirmed using a $\beta-galactosidase linked assay and polymerase chain reaction.

• International Journal of Computer Science & Network Security
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• v.21 no.4
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• pp.41-46
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• 2021

The article studies the implementation of automation in the education process as a convenient interface of a document management system, on the one hand, which makes it easy to navigate the program, requiring from the user only a small amount of any special skills in working with electronic computers, on the other hand, it provides to the user operational information about all the data of interest to him, taking into account the access rights given to this or that information, stored in the enterprise database.

• Journal of Korea Multimedia Society
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• v.24 no.3
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• pp.423-430
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• 2021

Aiming Graph convolutional networks (GCNs) have achieved outstanding performances on skeleton-based action recognition. However, several problems remain in existing GCN-based methods, and the problem of low recognition rate caused by single input data information has not been effectively solved. In this article, we propose a Dual-stream fusion method that combines video data and skeleton data. The two networks respectively identify skeleton data and video data and fuse the probabilities of the two outputs to achieve the effect of information fusion. Experiments on two large dataset, Kinetics and NTU-RGBC+D Human Action Dataset, illustrate that our proposed method achieves state-of-the-art. Compared with the traditional method, the recognition accuracy is improved better.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.13 no.2
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• pp.1-9
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• 1984

This paper presents design conditions due to the NTU of counter and cross flow type cooling tower. In the calculation of optimum design conditions for above two types which are widely used in our country, standard water-air ratio, ambient wet bulb temperature and bulk water temperature were adopted by domestic wheather conditions. The important result of this study is obtained as follows : Under the constant value of Ka and L, the number of transfer unit of cross flow type cooling tower Is about 1.1 times as large as that of counter, so the volume of cross flow type is about $10\%$ greater than that of counter.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.2
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• pp.279-289
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• 2000

The objective of this study was to investigate the effect of coagulants and solid-liquid separation methods on algal removal in water treatment processes. Thus characterization of raw water quality in terms of turbidity. UV-254, $KMnO_4$ consumption, chlorophyll-a and correlation analysis of these parameters were conducted. In addition, the effect of commercial Al-based coagulants(Alum. PAC and PACS) on algal removal was studied by turbidity and organic removal, algal species removal, characteristic of pH drop and alkalinity consumption using laboratory jar tests. Organic components including UV-254, $KMnO_4$ consumption, chlorophyll-a in case of algal bloom were highly correlated with turbidity and the correlation coefficients of UV-254, $KMnO_4$ consumption, chlorophyll-a with turbidity were 0.775, 0674 and 0.623, respectively. In coagulation and sedimentation, the Al-based coagulants showed similar efficiency of organic and turbidity removal in low organic($KMnO_4$ consumption below 15mg/l) and low turbidity(below 30NTU). However, PAC and PACS showed better algal removal than alum in high organic concentration($KMnO_4$ consumption above 20mg/l) and high turbidity(above 100NTU) raw water conditions generated by high algal growth, which is considered to be due to the floc settleability. In comparison of sedimentation and flotation after chemical coagulation and flocculation, the removal efficiency of organic and turbidity were higher in case of alum dose with flotation than with sedimentation, while those were better in case or PAC and PACS with sedimentation than with flotation. Thus, Alum with flotation and PAC and PACS with sedimentation is recommended for efficient algal removal. The dominant phytoplankton in raw water were Microcystic and pediastrum simplex and the removal efficiency of algae with sedimentation using alum. PAC and PACS were 27%, 45% and 22% respectively, while those with DAF showed 100% removal of phytoplankton and zooplankton.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.4
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• pp.493-501
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• 2007

The membrane pilot plant has being operated in the Hyeondo pumping station to find the optimal operation technique of Gong-Ju membrane water treatment plant (WTP) which is constructing in $250m^3/d$ scale. The pilot plant was consisted of two trains which can treat $30,000m^3/d$ per train. First train was operated for one year under the condition of flux $1m^3/m^2{\cdot}d$ while the effects of flux variation and addition of powdered activated carbon(PAC) were evaluated in second train. The turbidity of membrane product water of first train which is operated on Flux $1m^3/m^2{\cdot}d$ was always below 0.05 NTU regardless of raw water turbidity. And also, the trance-membrane pressure(TMP) was maintained at $0.3{\sim}0.5kgf/cm^2$ for about 9 months and increased rapidly to $1.8kgf/cm^2$ which is maximum operating TMP. However, TMP was rapidly increased to $1.8kgf/cm^2$ within 2 months as flux was increased from 1 to $2m^3/m^2{\cdot}d$, especially, within 10 days under high turbidity(30~50NTU). This reault means that if Gongju membrane WTP is operated in flux $1m^3/m^2{\cdot}d$, chemical cleaning period can be maintained over 6 months. Only 10% of dissolved organic carbon (DOC) was removed in membrane process while the removal efficiencies of manganese and iron were 60% and 77% respectively. However, because only solid manganese and iron were removed in membrane process, an additional process for treating soluble manganese is required if souble manganese is high in raw water. 70% of 70ng/L 2-MIB which is causing taste & odor was removed in powdered activated carbon (PAC) tank with 50mg/L PAC which is design concentration of Gongju WTP. In addition, TMP was reduced with addition of 50mg/L PAC regardless of flux. Because TMP was not influenced even if 100mg/L PAC was added, the high taste and odor problem can be controled by additional injection of PAC.