• Applied Chemistry for Engineering
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• v.10 no.3
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• pp.367-373
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• 1999

Increasing consumer demand for recycle of most paper products is challenging manufacturers to use lower value raw materials while maintaining high quality. This study was carried out to investigate the composition of old corrugated containers (OCC) and to manufacture printing and writing papers of over 85% (ISO) brightness by ECF and TCF bleaching from OCC. Fiber length of American old corrugated container (AOCC) was longer than that of Korean old corrugated container (KOCC) in fiber length. The former was composed of unbleached kraft pulp (UKP) of about 80 percentage, the latter about 20 percentage. OCC is feasible for manufacturing of pulps i.e., AOCC is for printing and writing papers and KOCC is for whiteboards, in the aspects of brightness and mechanical properties on the other hand, the cost of manufacturing upgraded papers by OCC is high because of bleaching chemicals. Neverthless, considering various aspects, especially environment, there are many advantages in recycling. In case of the treated AOCC pulp, over 85% (ISO) brightness can be achieved through TCF or ECF bleaching step, while the treated KOCC pulp did not allow high brightness through TCF bleaching. The tensile index of the bleached KOCC pulp was lower than that of the bleached AOCC pulp, but the burst and tear index of KOCC was higher than that of AOCC.

• Journal of Korean Society on Water Environment
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• v.28 no.5
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• pp.729-742
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• 2012

Recently, to using chemical coagulation process for T-P removal in STP effluent as tertiary treatment process is generalized in the country. The importance of analysis technique to save the treatment & maintenance cost during coagulation process is becoming more increased each day. Thus, it is necessary for the analysis technique during coagulation process to be presented well the characteristic of coagulation in field apply. There are a few analysis techniques such as Jar Test, zeta potential analysis and streaming current detecting techniques. But there are difficult to apply in field immediately due to long test time and difficult analysis techniques. And using PDA technique, it is reviewed applicability of the techniques as field index on pilot plant of P-CAP system The P-CAP system is composed of an in-line static mixer, a Flocculation Tank and the CAP reactor with 2 stage weir for effluent. Pre-test is performed to fix the mixing velocity in the Flocculation Tank using the PDA equipment and it fixed with 30RPM. Also, Jar Test is performed to select optimum dose of each coagulant for each T-P concentration level of influent. Result of continuous test on pilot plant of P-CAP system, the FSI in the Flocculation Tank is increased consistently by increasing each dosing concentration of coagulant such as LAS and PAC in the low level influent T-P concentration comparatively. It is considered that formed Al-hydroxide complexes for dosed coagulant are caused FSI variation. Furthermore, it seems that FSI value in the high level influent T-P concentration appeared lower than the opposite influent condition relatively because it is formed simultaneously Al-hydroxide complexes as solid type and Al-phosphorus complexes as soluble type. Thus, relation of FSI by PDA technique and T-P removal of final effluent on pilot plant of P-CAP system are very limited for the kind of coagulant and the characteristics of influent. And it though that FSI value by PDA technique with analyzing of turbidity in Flocculation Tank will be used restrictedly on field as the relative field-index.

• Korean Journal of Construction Engineering and Management
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• v.18 no.1
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• pp.58-64
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• 2017

Construction Management (CM) is being utilized as an efficient project management system. Construction management system provide scientific management techniques as well as the expert's service with the expertise. Accordingly, CM services demand is continuously increasing in construction project. Construction Management engineer grade is distinguished by the Index of Construction Engineer's Competency (ICEC). Construction management engineer requires a higher score than the other fields. However, junior grade CM engineer can get grade according to the education and qualification. This study was conducted junior grade CM engineer depth interview after analyzing the problem of the current CM engineer grade system. As a result, this study was to extracted the 23 kind competence factors. And, competence factors were five area grouped using affinity diagram method. Next, we analyzed the importance utilizing the Analytic Network Process (ANP) technique. As a result, high priority areas were analyzed to be quality and cost areas associated with project management.

• Journal of Bio-Environment Control
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• v.20 no.4
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• pp.304-310
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• 2011

To evaluate the effect of curing treatment using a newly developed simplified curing unit (SCU) on the physicochemical quality of stored sweet potatoes was investigated for six months. The SCU consisting of a heater, an air circulation fan, exhaust fans, and a humidifying duct was installed in a cold storage room where the harvested sweet potatoes were stacked. During the six days of curing treatment, air temperature and relative humidity in the storage room were set at $32^{\circ}C$ and 90%, respectively. Physical and chemical properties of sweet potatoes were measured at 1-month intervals from the first day of storage. McKinney index showing the incidence and severity of decay was 0.83% in the curing treatment, while that of untreated control was 5.08% over the same storing period. Firmness, soluble solids content, and dry matter content in the cured sweet potatoes were greater than those of untreated control. Moreover, the changes of skin color in uncured potatoes occurred rapidly than cured one which showed delay of skin discoloration during the long-term storage. Results suggest that the SCU treatment improves the physicochemical quality of stored sweet potatoes and extends their storability. Therefore, the SCU can be effectively used for curing treatment of sweet potatoes with a relatively low cost.

• Clinical and Experimental Reproductive Medicine
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• v.22 no.2
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• pp.131-141
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• 1995

This study was designed to determine the relationship between sperm acrosome reaction following ionophore challenge(ARIC) and hamster ovum sperm penetration assay(SPA) as assessment of fertilizing capacity of male. ARIC test and SPA were performed in 23 fertile and 19 subfertile men. The results were as follows; Sperm concentration was significantly higher in fertile group compared with subfertile group: $114.6{\pm}64.40$ vs $61.3{\pm}46.50{\times}10^6/ml$. However, there were no significantly differences in seminal volume, motility and motility index, respectively. There was a significantly correlation between spontaneous and induced AR in fertile and subfertile group, respectively. ARIC value was significantly higher in fertile group, compared with subfertile group: $12.0{\pm}5.57%$ vs $2.6{\pm}4.96%$. Both Penetration rate(PR) and Penetration index(PI) were significantly higher in fertile group, compared with subfertile group: $97.4{\pm}7.40%$ vs $64.9{\pm}36$. 20% and $5.4{\pm}2.88$ vs $1.5{\pm}1.47$, respectively. The Positive predictive value(PPV), Negative predictive value(NPV), sensitivity and specificity of ARIC test (cut-off: 8.5) and SPA(PI cut-off : 3.0) in predicting fertility were 95.0%, 81.8%, 82.6%, 94.7% and 95.2%, 85.7%, 87.0% and 94.7%, respectively. There was no significantly difference in predicting fertility between ARIC test and SPA. In conclusion, ARIC test was shown to have a predictive value for fertilizing capacity comparable to that of the hamster ovum sperm penetration assay. Therefore, ARIC test may be a simple and cost-effective addition to existing semenology instead of SPA.

• Journal of Korea Water Resources Association
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• v.44 no.5
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• pp.377-388
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• 2011

Surface Image Velocimetry (SIV) is a recently-developed discharge measurement instrument. It uses image processing techniques to measure the water surface velocity and estimate water discharge with given cross section. The present study aims to implement a FSIV (Fixed-type Surface Image Velocimetry) at Soojeon Bridge in the Dalcheon. The hardware system consists of two digital cameras, a computer, and a pressure-type water stage gauge. The images taken with the hardware system are sent to a server computer via a wireless internet, and analyzed with a image processing software (SIV software). The estimated discharges were compared with the observed discharges through Goesan dam spillway and index velocity method using ADVM. The computed results showed a good agreement with the observed one, except for the night time. The results compared with discharges through Goesan dam spillway reached around 5~10% in the case of discharge over 30 m3/s, and the results compared with discharges through index velocity method using ADVM reached around 5% in the case of discharge over 200 $m^3/s$. Considering the low cost of the system and the visual inspection of the site situation with the images, the SIV would be fairly good way to measure water discharge in real time.

• KIPS Transactions on Computer and Communication Systems
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• v.7 no.8
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• pp.195-202
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• 2018

With the development of location-based applications such as smart phones and GPS navigation, active research is being conducted to protect location and trajectory privacy. To receive location-related services, users must disclose their exact location to the server. However, disclosure of users' location exposes not only their locations but also their trajectory to the server, which can lead to concerns of privacy violation. Furthermore, users request from the server not only location information but also multimedia information (photographs, reviews, etc. of the location), and this increases the processing cost of the server and the information to be received by the user. To solve these problems, this study proposes the EGTC (Enhanced Grid-based Trajectory Cloaking) technique. As with the existing GTC (Grid-based Trajectory Cloaking) technique, EGTC method divides the user trajectory into grids at the user privacy level (UPL) and creates a cloaking region in which a random query sequence is determined. In the next step, the necessary information is received as index by considering the sub-grid cell corresponding to the path through which the user wishes to move as c(x,y). The proposed method ensures the trajectory privacy as with the existing GTC method while reducing the amount of information the user must listen to. The excellence of the proposed method has been proven through experimental results.

• Journal of KIISE:Databases
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• v.31 no.3
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• pp.261-273
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• 2004

Advances in information and communication technologies have been creating new classes of applications in the area of databases. For example, in moving object databases, which track positions of a lot of objects, or stream databases, which process data streams from a lot of sensors, data Processed in such database systems are usually changed very rapidly and continuously. However, traditional database systems have a problem in processing these rapidly and continuously changing data because they suppose that a data item stored in the database remains constant until It is explicitly modified. The problem becomes more serious in the R-tree, which is a typical index structure for multidimensional data, because modifying data in the R-tree can generate cascading node splits or merges. To process frequent updates more efficiently, we propose a novel update technique for the R-tree, which we call the leaf-update technique. If a new value of a data item lies within the leaf MBR that the data item belongs, the leaf-update technique changes the leaf node only, not whole of the tree. Using this leaf-update manner and the leaf-access hash table for direct access to leaf nodes, the proposed technique can reduce update cost greatly. In addition, the leaf-update technique can be adopted in diverse variants of the R-tree and various applications that use the R-tree since it is based on the R-tree and it guarantees the correctness of the R-tree. In this paper, we prove the effectiveness of the leaf-update techniques theoretically and present experimental results that show that our technique outperforms traditional one.

• Korean Journal of Optics and Photonics
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• v.12 no.2
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• pp.135-142
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• 2001

Recently, plastic optical fiber draws a lot of attention as a new transmission medium for local area network (LAN) and home network applications. As PMMA based GI-POF (Graded Index Plastic Optical Fiber) has very low loss at about 500 nm and 650 nm wavelengths, it is very important to have a compact ultra short optical pulse source at these wavelength windows. In this paper, we have investigated detailed characteristics of gain switched laser system by using a commercially available low cost RF devices and an InGaAlP Fabry Perot semiconductor laser operating at 650 nm wavelength. The shortest optical 'pulse obtained was 33 psec with 1 GHz repetition rate. Depending on the DC bias current and the modulation frequency, the FWHM and the pulse energy of the gain switched pulses show 33.3-82.8 psec and 0.97-9.69 pI respectively. Also, the spectral bandwidths for CW and gain switched operations are 0.44 nm and 1.50 nm. We believe that these results are quite useful for high bit rate optical transmission applications with PMMA based plastic optical fibers in addition to estimate properties of ultra fast optical components and electro-optic devices. vices.

• International Area Studies Review
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• v.15 no.2
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• pp.247-273
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• 2011

This study analyzes the impacts on the M&A and greenfield of macroeconomic variables of home and host countries, after identifying current status and characteristics of the M&A and greenfield related to the entering way of Korean firms in China. Main empirical results are summarize as follows. First, as for foreign exchange variable, the decreased value of Korea won shows the negative correlations with both of the greenfield and M&A. Second, the real interest rate of Korea to measure the cost of capital is not significant statistically. Third, while the host country's stock market index, Shanghai Comprehensive Index, shows the expected negative correlations with the investment in the case of small & medium firm and light industry, it shows the positive correlations which is not consistent with general expectation in the case of large firm and heavy industry. Fourth, the openness of host country shows the positive correlations with both of the greenfield and M&A. Finally, in regard to the M&A, China's GDP to measure the market size of host country is not significant statistically while it shows the strong positive relationship with the greenfield investment.