• Journal of Korea Water Resources Association
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• v.41 no.8
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• pp.761-772
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• 2008

The object of this study is to develop the model that solves the numerically difficult problems in hydraulic engineering and to demonstrate the applicability of this model by means of various test examples, such as, verification in the gradually varied unsteady condition, three steady flow problems with the change of bottom slope with exact solution, and frictional bed with analytical solution. The governing equation of this model is the integral form of the Saint-Venant equation satisfying the conservation laws, and finite volume method with the Riemann solver is used. The evaluation of the mass and momentum flux with the HLL Riemann approximate solver is executed. MUSCL-Hancock scheme is used to achieve the second order accuracy in space and time. This study introduce the new and simple technique to discretize the source terms of gravity and hydrostatic pressure force due to longitudinal width variation for the balance of quantity between nonlinear flux and source terms. The results show that the developed model's implementation is accurate, robust and highly stable in various flow conditions with source terms, and this model is reliable for one-dimensional applications in hydraulic engineering.

• Polymer(Korea)
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• v.25 no.1
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• pp.6-14
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• 2001

The monomer N,N'-bis(3-pyrrol-1-yl-propyl)-4,4'-bipyridinium$(PF_6)_2$ was electrochemically polymerized on glassy carbon electrode surface. This polymer film electrode has electroactive sites on its bipyridinium ions distributed at the polymer strands. The formal potentials of the electrodes were -0.41V and -0.81V(vs. SSCE) for each step at phosphate buffer(pH=5.70). The diffusion coefficients of the dopants ions into the polymer matrix were $1.57{\times}10^{-4}$ and $4.35{\times}10^{-5}cm^2s^{-1}$ for first and second redox couple, respectively. The rate constants of electron transfer at $V^{2+/+}$ of the first step was a $57.53s^{-1}$, which was 22 times higher than $V^{+/0}$ one having $2.63s^{-1}$ in the solution. The charge transfer resistance of the polymer film was influenced by the dopant ion of the electrolyte. Thus the resistances were 22.63, 16.81, 12.44 and $11.36k{\Omega}$ for $LiClO_4,\;NaClO_4,\;KClO_4$, and phosphate buffer, respectively. The reaction order of the electropolymerization was first order and the rate constant of the polymerization was $1.31{\times}10^{-1}s^{-1}$ as determined by EQCM method. The G.C./p-BPB type electrode doped with phosphate ions showed a stability and reproducibility in CV procedure over 20 cycles.

• Journal of KIISE:Databases
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• v.29 no.6
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• pp.453-463
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• 2002

With the prevalence of multi-dimensional data such as images, content-based retrieval of data is becoming increasingly important. To handle multi-dimensional data, multi-dimensional index structures such as the R-tree, Rr-tree, TV-tree, and MVP-tree have been proposed. Numerous research results on how to effectively manipulate these structures have been presented during the last decade. Query processing strategies, which is important for reducing the processing time, is one such area of research. In this paper, we propose query processing algorithms for R-tree based structures. The novel aspect of these algorithms is that they make use of the notion of VP filtering, a concept borrowed from the MVP-tree. The filtering notion allows for delaying of computational overhead until absolutely necessary. By so doing, we attain considerable performance benefits while paying insignificant overhead during the construction of the index structure. We implemented our algorithms and carried out experiments to demonstrate the capability and usefulness of our method. Both for range query and incremental query, for all dimensional index trees, the response time using VP filtering was always shorter than without VP filtering. We quantitatively showed that VP filtering is closely related with the response time of the query.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.6000-6007
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• 2013

Cr(VI)-heterocyclic complex[Cr(VI)-isoquinoline] was synthesized by the reaction between of heterocyclic compound(isoquinoline) and chromium trioxide, and characterized by IR and ICP analysis. The oxidation of benzyl alcohol using Cr(VI)-isoquinoline in various solvents showed that the reactivity increased with the increase of the dielectric constant(${\varepsilon}$), in the order : cyclohexene$CH_3$, m-Br, m-$NO_2$). Electron- donating substituents accelerated the reaction, whereas electron acceptor groups retarded the reaction. The Hammett reaction constant(${\rho}$) was -0.69(308K). The observed experimental data have been ratiolized. The hydride ion transfer causes the prior formation of a chromate ester in the rate-determining step.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.1
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• pp.56-63
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• 2016

In this study, we introduce a design of Fuzzy RBFNNs-based digit recognition system using the incremental-PCA in order to recognize the handwritten digits. The Principal Component Analysis (PCA) is a widely-adopted dimensional reduction algorithm, but it needs high computing overhead for feature extraction in case of using high dimensional images or a large amount of training data. To alleviate such problem, the incremental-PCA is proposed for the computationally efficient processing as well as the incremental learning of high dimensional data in the feature extraction stage. The architecture of Fuzzy Radial Basis Function Neural Networks (RBFNN) consists of three functional modules such as condition, conclusion, and inference part. In the condition part, the input space is partitioned with the use of fuzzy clustering realized by means of the Fuzzy C-Means (FCM) algorithm. Also, it is used instead of gaussian function to consider the characteristic of input data. In the conclusion part, connection weights are used as the extended diverse types in polynomial expression such as constant, linear, quadratic and modified quadratic. Experimental results conducted on the benchmarking MNIST handwritten digit database demonstrate the effectiveness and efficiency of the proposed digit recognition system when compared with other studies.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.8
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• pp.886-891
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• 2005

In this study, a novel bioreactor system using a submerged hollow fiber membrane module (so called hollow fiber membrane bioreactor, HFMB) was applied to investigate feasibility and biodegradation capacity of the system for the treatment of gaseous toluene. First an abiotic test was conducted to determine the mass transfer coefficient, showing the value was similar to that obtained from a diffuser system using fine bubbles. Second, in the presence of toluene-degrading microorganisms, the HFMB was operated at different inlet toluene loading rates of 50, 100, $500\;g/m^3/hr$, and overall removal efficiencies were maintained in the range of $70{\sim}80%$. In addition, elimination capacities(EC) were increased up to $800\;g/m^3/hr$, which was substantially higher than maximum ECs for toluene reported in the biofiltration literature. Consequently, the HFMB was considered as an alternative method over other conventional VOC-treating technologies.

• Korean Journal of Environmental Agriculture
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• v.21 no.3
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• pp.197-201
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• 2002

This study was conducted in Jeju Island to find the effects of livestock manure application on the changes in soil salt concentration and $NO_3-N$ contents. Soil samples were collected from Goojua-Tong (volcanic ash soil) and Aewol-Tong(non-volcanic ash soil) to 50 cm depth and were mixed with livestock manure to 20 cm depth in PVC container(30 cm diameter, 1 m height). Animal manures of cattle, pig, and fowl were adjusted to 0, 50, 100,150 ton/ha. Animal manure applications increased the salt concentrations in soil. The salt concentration was increased as the fowl manure amount was increased The effects were larger in order of fowl manure > cattle manure $\fallingdotseq$ pig manure. $NO_3-N$ contents in soil showed a sharp increase by applications of fowl manure, but the increase was slow when the cattle and pig manures were applied. In volcanic ash soil, there was no change in phosphate contents by application of animal manures, but the phosphate contents increased in non-volcanic ash soil with the application of animal manure, especially by fowl manure.

• Applied Microscopy
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• v.33 no.4
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• pp.261-266
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• 2003

The growth patterns of primary culture of bovine brain microvessel endothelial cells (BBMECs) were studied using electron microscopy when grown on $3.0{\mu}m$ and $0.4{\mu}m$ pore Transwell. The capillary fragments and isolated endothelial cells grew on collagen coated culture plate and Transwell membrane. The BBMECs grew only on the upper surface of membrane of $0.4{\mu}m$. But BBMECs on $3.0{\mu}m$ pore membrane migrated through the pore and grew on the opposite side of the membrane. In summary, BBMECs isolated by enzyme digestion could migrate through $3.0{\mu}m$ pore membrane but not through $0.4{\mu}m$ pore membrane. So $0.4{\mu}m$ pore membrane instead of $3{\mu}m$ pore membrane should be used for drug transport experiment or transendothelial electrical resistance measurement.

• Radiation Oncology Journal
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• v.8 no.1
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• pp.65-71
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• 1990

Between January,1974 and December 1980, fifty eight patients with locoregional recurrent breast carcinoma who did not have evidence of distant metastasis after initial treatment of surgery with or without adjuvant chemotherapy were treated with radiation therapy. Among them, five patients were excluded from this study because of incomplete record or incomplete treatment. The 5-year overall survival and disease free survival from the time of locoregional recurrence was $27\%\;and\;15\%$ respectively. In univariate analysis of prognostic variables, the clinical stage at initial diagnosis, recur duration, number of recurrence sites, size of recurrences, response to the treatment, remission duration were all found to have no significant effect on survival or disease free survival. On the other hand, menopausal status at initial diagnosis, number of positive node at initial surgery, whether or not the use of adjuvant chemotherapy after initial mastectomy had definite prognositc significance. In multivariate analysis of prognostic variables, remission duration, menopausal status at diagnosis, number of axillary node at mastectomy had definite prognostic significance. On the other hand, remission duration more than 12 months, premenopaus at initial mastectomy, less than four positive axillary lymph nodes at mastectomy predicted a good prognosis.

• Korean Journal of Food Science and Technology
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• v.48 no.6
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• pp.536-541
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• 2016

The purpose of this study was to evaluate changes in the quality characteristics of mackerel fish fillet under freezing storage conditions. The changes in product quality were determined by measuring pH, volatile basic nitrogen (VBN); thiobarbituric acid (TBA), lightness ($L^*$), redness ($a^*$), yellowness ($b^*$) values, shearing force, and microbiological evaluation (Total Plate Count, TPC) during 21 days of storage at -20, -5, and $-1^{\circ}C$, and their shelf-lives were established. TPC as an effective quality indicator was used to estimate the shelf-life via linear regression analysis. The TPC increased steadily with increasing storage periods at every temperature (p<0.05) and showed a significant relationship with temperature at $-1^{\circ}C$ (r=0.949), $-5^{\circ}C$ (r=0.919), and $-20^{\circ}C$ (r=0.905). Therefore, based on TPC, the shelf life of the mackerel fillet was noted to be 32 days when stored at $-1^{\circ}C$, more than 51 days when stored at $-5^{\circ}C$, and about 2 months when stored at $-20^{\circ}C$.