• Computers and Concrete
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• v.20 no.1
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• pp.1-10
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• 2017

This paper focuses on the mesh-size dependency in numerical simulations of reinforced concrete (RC) structures subjected to blast loading. A tensile failure criterion that can minimize the mesh-dependency of simulation results is introduced based on the fracture energy theory. In addition, conventional plasticity based damage models for concrete such as the CSC model and the HJC model, which are widely used for blast analyses of concrete structures, are compared with the orthotropic model that adopts the introduced tensile failure criterion in blast tests to verify the proposed criterion. The numerical predictions of the time-displacement relations at the mid-span of RC beams subjected to blast loading are compared with experimental results. The analytical results show that the numerical error according to the change in the finite element mesh size is substantially reduced and the accuracy of the numerical results is improved by applying a unique failure strain value determined by the proposed criterion.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.8
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• pp.1311-1317
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• 2008

In this paper, a fault location algorithm using wavelet transform is proposed for HVDC cable lines. The arriving instants of the first and second fault-induced backward travelling waves can be detected by using wavelet transform. The fault distance is estimated by using the time difference between the two instants of backward travelling waves and the velocity of the travelling wave. To distinguish between the backward wave from fault point and the backward wave from the remote end, polarities of backward waves are used. The proposed algorithm is verified varying with fault distances and fault resistances in underground cables of VSC(voltage source converter) HVDC system and CSC(Current Source Converter) HVDC respectively. Performance evaluations of the proposed algorithm shows that it has good ability for a fault location of HVDC cable faults.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.548-549
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• 2014

In Jeju power sytstem, the generation of reactive power depends on the operation of CSC-HVDC filter. Thus, the grid voltage will be affected. Statcom and SVC have demonstrated that it has excellent charateristics to solve this problem. First, this paper analyzes the operation of the Statcom based on the real power system in Jeju. Then, the characteristics of Statcom will be compared to the SVC. The modelling of the Jeju power system including Statcom and SVC will be performed by using PSCAD/EMTDC program and the real data from the real Jeju power system.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.357-358
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• 2015

This paper provides a comparison of power converter loss and thermal description for voltage source and current source type 5MW-class medium voltage topologies of wind turbines. Neutral-point clamped three-level converter is adopted for voltage source type topology while two-level converter is employed for current source type topology considering the popularity in the industry. In order to match the required voltage level of 4160V with the same switching device of IGCT as in voltage source converter, two active switches are connected in series for the case of current source converter. The loss analysis is confirmed through PLECS simulations. In addition, the loss factors due to di/dt and dv/dt snubber and ac input filter are presented. The comparison result shows that VSC-based wind turbine system has a higher efficiency than that of CSC under the rated operating conditions.

• International Journal of Advanced Culture Technology
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• v.9 no.3
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• pp.283-290
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• 2021

Recently, correlated superposition coding (CSC) has been proposed to implement non-orthogonal multiple access (NOMA) without successive interference cancellation (SIC), without loss of spectral efficiency, in contrast to conventional independent superposition coding (ISC). However, correlation between signals has reduced the average total allocated power, which results in degraded performance. Thus, in order to avoid the reduction of the average total allocated power owing to correlation between signals, this paper proposes a cross-correlated quadrature amplitude modulation (QAM) NOMA scheme under Rayleigh fading channel surroundings. First, we design the cross-correlated QAM NOMA scheme. Then, simulations demonstrate that for the weaker channel gain's user, the symbol error rate (SER) performance of the proposed cross-correlated QAM NOMA improves largely, whereas for the stronger channel gain's user, the SER performance of the proposed cross-correlated QAM CSM NOMA degrades little, compared to that of the conventional QAM NOMA.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.59-60
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• 2021

To measure the effect of the stress-strain dispersion across the installed waterproofing layer on the concrete surface, a strain gauge was attached to the gap between the waterproofing layer and the concrete structure at specified points of upper, center and bottom of the load-displacement simulation specimen, and the peak stress-strain at the displacement interface were measured and compared with stress-strain at other areas to analyze each material types' stress-strain dispersion ratio properties. Based on the results of the testing, it was shown that materials with high load-displacement resistance performance accordingly had high stress-strain dispersion ratio results, and the materials from highest performance to lowest performance were; CAS, SAS, PUC and CSC.

• BMB Reports
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• v.48 no.2
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• pp.68-80
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• 2015

G protein-coupled receptors (GPCRs) are a large class of transmembrane receptors categorized into five distinct families: rhodopsin, secretin, adhesion, glutamate, and frizzled. They bind and regulate 80% of all hormones and account for 20-50% of the pharmaceuticals currently on the market. Hundreds of GPCRs integrate and coordinate the functions of individual cells, mediating signaling between various organs. GPCRs are crucial players in tumor progression, adipogenesis, and inflammation. Several studies have also confirmed their central roles in embryonic development and stem cell maintenance. Recently, GPCRs have emerged as key players in the regulation of cell survival, proliferation, migration, and self-renewal in pluripotent (PSCs) and cancer stem cells (CSCs). Our study and other reports have revealed that the expression of many GPCRs is modulated during the generation of induced PSCs (iPSCs) or CSCs as well as during CSC sphere formation. These GPCRs may have crucial roles in the regulation of self-renewal and other biological properties of iPSCs and CSCs. This review addresses the current understanding of the role of GPCRs in stem cell maintenance and somatic reprogramming to PSCs or CSCs.

• Journal of Korean Ophthalmic Optics Society
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• v.21 no.3
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• pp.281-288
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• 2016

Purpose: The present study was aimed to investigate the change of optical quality in fully cured eyes from central serous chorioretionopathy(CSC) and CSC under treatment, respectively. Methods: A total of 136 eyes(68 subjects) was divided into CMC under treatment and its asymptomatic contralateral eye, fully cured eyes after being diagnosed with CMC and its contralateral eye, and normal eyes. Objective scattering index, cut-off value in modulation transfer function, focusing rate, PSF(Point Spread Function) width at 50%, 10% and the contrast sensitivity were measured and analyzed. Results: CMC under treatment showed statistically significant decrease in all evaluations of optical quality compared with asymptomatic contralateral eyes, fully cured eyes and normal eyes. Although there was no significant difference in optical quality between asymptomatic contralateral eyes of CMC under treatment and fully cured eyes, there was tendence in optical quality decreasing compared with normal eyes. Conclusions: From the study, it was revealed that the optical quality was different according to the treatment phase in CMC. The use of optical quality assessment for the decision of complete cure and the evaluation of prognosis in CMC is also proposed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.4
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• pp.648-652
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• 2002

Removing shup from oyster by aeration method and coating with edible coating materials were investigated to improve oyster quality for the retort processing. Aeration rate and pore size of nozzle were critical factors to remove shup by aeration method. Optimum aeration rate and nozzle size were 45 L/min and 0.4 mm, respectively, when aeration was peformed two times and each operation maintained for 1 minute. Sodium alginate (SA) was used for oyster as the basal coating material. However, SA affected mouth-feel when it was applied at high concentrations. Sub-coating materials including skim milk, waxy corn starch, Purity CSC, white corn starch and carboxymethylcellulose (CMC) in decreasing order showed a positive effect on improving coatability and mouth-feel. Therefore, it is suggested that 1.5% SA and 0.9% skim milk should be the optimum composition of coating materials for oyster. Browning and syneresis of the porridge containing the coated oyster were considerably inhibited as compared with the sample without the coated oyster.

• The KIPS Transactions:PartB
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• v.10B no.6
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• pp.673-680
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• 2003

In this paper, we study the enhancement of VQ (Vector Quantization) design for text independent speaker recognition. In a concrete way, we present a non-iterative method which makes a vector quantization codebook and this method performs non-iterative learning so that the computational complexity is epochally reduced The proposed Classified Space VQ (CSVQ) design method for text Independent speaker recognition is generalized from Semi-noniterative VQ design method for text dependent speaker recognition. CSVQ contrasts with the existing desiEn method which uses the iterative learninE algorithm for every traininE speaker. The characteristics of a CSVQ design is as follows. First, the proposed method performs the non-iterative learning by using a Classified Space Codebook. Second, a quantization region of each speaker is equivalent for the quantization region of a Classified Space Codebook. And the quantization point of each speaker is the optimal point for the statistical distribution of each speaker in a quantization region of a Classified Space Codebook. Third, Classified Space Codebook (CSC) is constructed through Sample Vector Formation Method (CSVQ1, 2) and Hyper-Lattice Formation Method (CSVQ 3). In the numerical experiment, we use the 12th met-cepstrum feature vectors of 10 speakers and compare it with the existing method, changing the codebook size from 16 to 128 for each Classified Space Codebook. The recognition rate of the proposed method is 100% for CSVQ1, 2. It is equal to the recognition rate of the existing method. Therefore the proposed CSVQ design method is, reducing computational complexity and maintaining the recognition rate, new alternative proposal and CSVQ with CSC can be applied to a general purpose recognition.