• Korea Trade Review
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• v.45 no.5
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• pp.181-200
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• 2020

The Korea-Canada FTA and the EVTA have adopted cross-cumulation clauses in their rules of origin, aiming at the enhancement of the value chains among the FTA parties. In fact, intricate rules of origin are often considered as the major cause that discourages the utilization of the agreement for the exporting firms. From this perspective, the correct understanding of cross-cumulation clauses in FTAs is an urgent mission for the Korean exporters as well, and the EVTA, which has recently introduced the cross-cumulation method in a linkage with the Korea-EU FTA provides the timely motivation. This paper first analyzes the Korea-Canada FTA of 2015 as for the case study, because this is a unique trade agreement for Korea that has already adopted the cross-cumulation clauses. It is concluded that the clause is rather vague, particularly in certifying the origins of the intermediate goods from the territory of an authorized third party. From this perspective, the recently-ratified EVTA is particularly important and meaningful with its clearer explanations for the utilization of the privileged rules of origin. The paper finalizes the study by making policy suggestions to the stakeholders, expecting more future FTAs to come equipped with similar cumulative rules of origin, and implies the possibility of the modification of the current clauses in the FTA with Canada.

• Wind and Structures
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• v.38 no.5
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• pp.367-379
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• 2024

Compared with traditional transmission towers, T-shaped angle towers have long cross-arms and are specially used for ultrahigh-voltage direct-current (UHVDC) transmission. Nevertheless, the wind loads of T-shaped towers have not received much attention in previous studies. Consequently, a series of wind tunnel tests on the T-shaped towers featuring cross-arms of varying lengths were conducted using the high-frequency force balance (HFFB) technique. The test results reveal that the T-shaped tower's drag coefficients nearly remain constant at different testing velocities, demonstrating that Reynolds number effects are negligible in the test range of 1.26 × 10⁴-2.30 × 10⁴. The maximum values of the longitudinal base shear and torsion of the T-shaped tower are reached at 15° and 25° of wind incidence, respectively. In the yaw angle, the crosswind coefficients of the tower body are quite small, whereas those of the cross-arms are significant, and as a result, the assumption in some load codes (such as ASCE 74-2020, IEC 60826-2017 and EN 50341-1:2012) that the resultant force direction is the same as the wind direction may be inappropriate for the cross-arm situation. The fitting formulas for the wind load-distribution factors of the tower body and cross-arms are developed, respectively, which would greatly facilitate the determination of the wind loads on T-shaped angle towers.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.5
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• pp.426-430
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• 2006

This paper deals with a novel utilization method of the predicted current in the high performance PI current controller with a control time delay. The inevitable error of the predicted current in the linear servo drive using a permanent magnet linear synchronous motor is analyzed and a modified cross-coupling decoupling synchronous frame PI current controller is proposed in order to improve the current control response under both the control time delay and the inevitable current prediction error. Simulation and experimental results show that the proposed current controller has an improved current control performance under both the control time delay and the inevitable current prediction error in the servo drive system.

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.5
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• pp.510-517
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• 2001

This paper describes an initial study for the application of eddy current pattern recognition approaches to more realistic flaw characterization in steam generator tubes. For this purpose, finite-element model-based theoretical eddy current testing (ECT) signals are simulated from 5 types of OD flaws with the variation in flaw size parameters and testing frequency. In addition, three kinds of software are developed for the convenience in the application of steps in pattern recognition approaches such as feature extraction feature selection and classification by probabilistic neural networks (PNNs). The cross point of the ECT signals simulated from flaws with non-symmetric cross-sections shows the deviation from the origin of the impedance plane. New features taking advantages of this phenomenon are added to complete the feature set with a total of 18 features. Then, classification with PNNs are performed based on this feature set. The PNN classifiers show high performance for the identification of symmetry in the cross-section of a flaw. However, they show very limited success in the interrogation of the sharpness of flaw tips.

• Korean Journal of Culture and Social Issue
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• v.24 no.1
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• pp.1-27
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• 2018

The purpose of this study was to identify the persistent and dynamic association between bullying and victimization. Gender differences in patterns of school bullying was hypothesized based on the literature. Analysis were based on waves 3-6 of the Korea Children and Youth Panel Survey, a nationally representative data of primary and secondary school students in South Korea (N = 1,881). Autoregressive cross-lagged model was employed to identify the reciprocal association between bullying and victimization in longitudinal data. As hypothesized, regardless of gender, lagged effects were statistically significant between each time points such that current bullying caused future bullying and current victimization led to future victimization. However, there was no cross-lagged effects of current victimization on future bullying nor current perpetration on future victimization for both male and female youth. Findings from this study may have implications for designing policies against school bulling. Not only is short-term intervention for handling immediate psycho-social maladjustment important, but so are long-term plans that prevent youth from falling into continued perpetration and victimization in the system of school bullying.

• The Korean Journal of Petroleum Geology
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• v.4 no.1_2 s.5
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• pp.12-19
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• 1996

Directional sedimentary structures (channel structure, cross stratification, and current ripple) were observed in fine to gravelly ye.y coarse sandstones of the Cretaceous Mayans Group (lljig, Hupyeongdong, and Jeomgok formations) in the northeastern part of Euiseong subbasin of Kyongsang basin, Southeast Korea. Large and small scale channel structures are common in all formations. Trough cross-stratification and channel structure frequently occur in the lljig formation (proximal fluvial deposit), whereas planar cross- stratification, cross lamination, and current ripple occur abundantly in the Hupyeongdong and Jeomgok formations (distal braided fluvial to marginal lacustrine deposits). The paleocurrent directions inferred from a statistical analysis of total 43 directional sedimentary structures show a mean azimuth of $290^{\circ}C$ with a standard deviation of $\pm68$. It suggests that the main flow of the paleocurrents moved toward the WNW direction and the source area of the sediments would be located somewhere in the ESE direction beyond the study area.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.8B
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• pp.707-718
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• 2008

The methodology of classifying traffics is changing from payload based or port based to machine learning based in order to overcome the dynamic changes of application's characteristics. However, current state of traffic classification using machine learning (ML) algorithms is ongoing under the offline environment. Specifically, most of the current works provide results of traffic classification using cross validation as a test method. Also, they show classification results based on traffic flows. However, these traffic classification results are not useful for practical environments of the network traffic monitoring. This paper compares the classification results using cross validation with those of using split validation as the test method. Also, this paper compares the classification results based on flow to those based on bytes. We classify network traffics by using various feature sets and machine learning algorithms such as J48, REPTree, RBFNetwork, Multilayer perceptron, BayesNet, and NaiveBayes. In this paper, we find the best feature sets and the best ML algorithm for classifying traffics using the split validation.

• Progress in Superconductivity and Cryogenics
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• v.14 no.2
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• pp.16-19
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• 2012

The influence of current distribution on the transport current loss in vertically stacked high-$T_c$ superconductor (HTS) tapes was evaluated. AC loss was analyzed as a function of current distribution by introducing a current distribution parameter through a numerical method (finite element analysis). AC loss under non-uniform current distribution is always higher than that for a uniformly distributed transport current in a conductor. Although the effect of non-uniformity is relatively insignificant in low transport current, AC loss increases substantially in high transport current regions as non-uniformity is enlarged. The results verify that non-uniform current distribution causes extra loss by examining the cross-sectional view of current densities in stacked conductor.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.3
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• pp.290-301
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• 2006

A push pull hood system is frequently applied to control contaminants evaporated from an open surface tank. Efficiency of push pull hood system is affected by various parameters, such as, cross draft, vessel shapes, tank surface area, liquid temperature. A previous work assisted by flow visualization technique qualitatively showed that a strong cross draft blown from the pull hood to push slot could destroy a stable wall-jet on the surface of tank, resulting in the abrupt escape of smoke from the surface. In this study, the tracer gas method was applied to determine the effect of cross-draft on the capture efficiency qualitatively. A new concept of capture efficiency was introduced, that is, linear efficiency. This can be determined by measuring the mass of tracer gas in the duct of pull hood while the linear tracer source is in between push slot and pull hood. By traversing the linear tracer source from the push slot to the pull hood, it can be found where the contaminant is escaped from the tank. Total capture efficiency can be determined by averaging the linear efficiencies. Under the condition of cross-draft velocities of 0, 0.4, 0.75, 1.05 and 1.47m/s, total capture efficiencies were measured as 97.6, 95.4, 94.6, 92.7 and 70.5% respectively. The abrupt reduction of efficiency with cross-draft velocity of 1.47m/s was due to the destruction of tank surface wall-jet by the counter-current cross-draft. The same phenomenon was observed in the previous flow visualization study. As an alternative to overcome this abrupt efficiency drop, the 20% increase of hood flow rates was tested, resulting in 20% efficiency increase.

• Journal of the Korean Wood Science and Technology
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• v.41 no.2
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• pp.158-163
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• 2013

Cross laminated timber (CLT) has been an rising issue as a promising building material replacing steel-concrete in mid story rise construction. But, there was no specific standard for CLT because it had been developed in industrial section. Recently, new draft for requirements of CLT was proposed by EN which suggested to evaluate the performance of adhesive in CLT by the same method as glulam. But, it has been reported that shear performance of cross laminated timber is governed by rolling shear. Therefore, block shear tests were carried out to compare parallel to grain laminating and cross laminating using commercial one component PUR (Poly urethane resin). The result showed that the current glulam standard for evaluating bonding performance is not appropriate for CLT. Beacause shear strength of cross laminating decreased to 1/3 of parallel to grain laminating and this strength was representing shear performance of wood itself not the bond. However, cross laminating showed no significant effect on wood failure. Thus, wood failure can be used as a requirement of CLT bonding. Based on the results, cross laminating effect should be included when evaluating adhesive performance of CLT correctly and should be considered as an important factor.