• Annals of Laboratory Medicine
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• v.38 no.6
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• pp.585-590
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• 2018

Background: Although testing to detect weak D antigens using the antihuman globulin reagent is not required for D- patients in many countries, it is routinely performed in Korea. However, weak D testing can be omitted in D- patients with a C-E- phenotype as this indicates complete deletion of the RHD gene, except in rare cases. We designed a new algorithm for weak D testing, which consisted of RhCE phenotyping followed by weak D testing in C+ or E+ samples, and compared it with the current algorithm with respect to time and cost-effectiveness. Methods: In this retrospective study, 74,889 test results from January to July 2017 in a tertiary hospital in Korea were analyzed. Agreement between the current and proposed algorithms was evaluated, and total number of tests, time required for testing, and test costs were compared. With both algorithms, RHD genotyping was conducted for samples that were C+ or E+ and negative for weak D testing. Results: The algorithms showed perfect agreement (agreement=100%; ${\kappa}=1.00$). By applying the proposed algorithm, 29.56% (115/389 tests/yr) of tests could be omitted, time required for testing could be reduced by 36% (8,672/24,084 min/yr), and the test cost could be reduced by 16.53% (536.11/3,241.08 USD/yr). Conclusions: Our algorithm omitting weak D testing in D- patients with C-E- phenotype may be a cost-effective testing strategy in Korea.

• Steel and Composite Structures
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• v.15 no.5
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• pp.507-518
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• 2013

The seismic performance of six types of weak-axis steel moment connections was investigated through cyclic testing of six full-scale specimens. These weak-axis moment connections were the column-tree type, WUF-B type, FF-W type, WFP type, BFP-B type and DST type weak-axis connections. The testing results showed that each of these weak-axis connection types achieved excellent seismic performance, except the WFP and the WUF-B types. The WFP and WUF-B connections displayed poor seismic performance because a fracture appeared prematurely at the weld joint due to stress concentrations. The column-tree type connection showed the best seismic behavior such that the story drift ratio could reach 5%.

• Geomechanics and Engineering
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• v.21 no.4
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• pp.315-326
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• 2020

The long-term behavior of rockfill material used in the construction of infrastructures such as dams is of great significance. Because of concerns about the application of weak rockfill material in dam construction, further experimental studies on the behavior of these materials are required. In this study, laboratory experiments were performed to investigate the one-dimensional deformation and particle breakage of the weak rockfill material under stress. A one-dimensional compression apparatus was designed and developed for testing of rockfill materials of different maximum particle sizes (MPSs). The compression tests were performed under dry, wet and saturated conditions on samples of rockfill material obtained from a dam construction site in Iran. The results of the experiments conducted at the specimen preparation stage and the 1D compression tests are presented. In weak rockfill, the effect of the addition of water on the behavior of the material was uncertain as there were both an increases and decreases observed in particle breakage. Increasing the MPS of the weak rockfill materials increased particle breakage, which was similar to the behavior of strong rockfill material. In all of the MPSs examined, the settlement of specimens under wet conditions was higher than that observed under dry conditions. Also, the greatest deformation occurred during the first hour of loading.

• Communications for Statistical Applications and Methods
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• v.22 no.2
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• pp.121-135
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• 2015

We consider testing equality of mean functions from two samples of functional data. A novel test based on the adaptive Neyman methodology applied to the Hotelling's T-squared statistic is proposed. Under the enlarged null hypothesis that the distributions of the two populations are the same, randomization methods are proposed to find a null distribution which gives accurate significance levels. An extensive simulation study is presented which shows that the proposed test works very well in comparison with several other methods under a variety of alternatives and is one of the best methods for all alternatives, whereas the other methods all show weak power at some alternatives. An application to a real-world data set demonstrates the applicability of the method.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.2
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• pp.184-193
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• 2008

The gate expansion was planed to increase discharge capacity of gate structure at sea dike in Asan Bay. So it was estimated for changing of hydraulic states in Pyeongteak Harbor Zone caused by gate expansion, using Delft3D, FLOW-3D and hydraulic physical scale model testing. In result, the influence of gate expansion was indicated to be weak.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.2
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• pp.177-186
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• 2002

This paper describes the magnetic flux leakage(MFL) type non-destructive testing(NDT) system to detect the 3D defects in underground gas pipe. Magnetic systems with permanent magnets and yokes are analyzed by 3D non-lineal finite element method(FEM) with optimum design. In case of under-saturation of gas pipe, sensing signals are too weak to detect. In case of over-saturation, the changes of the sensing signals are too low to detect the defects sensitively. So, the operating points of the magnetic system are optimized to increase the changes of the MFL signals. The effects of the depth and size of the defects on the sensing signals are analyzed to define the range and resolution of the MFL sensors. To increase the sensor's sensitivity, the back-yoke sensors are introduced and tested.

• Computers and Concrete
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• v.2 no.3
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• pp.239-248
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• 2005

The article presents the results of examination of the fractal dimension D of concrete specimen fracture surfaces obtained in fracture toughness tests. The concretes were made from three different types of coarse aggregate: gravel, dolomite and basalt aggregate. Ordinary concretes (C40) and high-performance concretes (HPC) were subjected to testing after 7, 14, 28 and 90 days of curing, respectively. In fracture toughness and compressive tests, different behaviours of concretes were found, depending on the type of aggregate and class of concrete (C40, HPC). A significant increase in the strength parameters tested occurred also after a period of 28 days (up to the $90^{th}$ day of curing) and was particularly large for concretes C40. Fractal examinations performed on fracture replicas showed that the fractal dimension D was diverse, depending on the coarse aggregate type and concrete class being, however, statistically constant after 7 and 14 days for respective concretes during curing. The fractal dimension D was the greater, the worse strength properties were possessed by the concrete. A cross-grain crack propagation occurred in that case, due to weak cohesion forces at the coarse aggregate/mortar interface. A similar effect was observed for C40 and HPC made from the same aggregate. A greater dimension D was exhibited by concretes C40, in which case the fracture was easier to form compared with high-performance concretes, where, as a result of high aggregate/mortar cohesion forces, the crack propagation was of inter-granular type, and the resulted fracture was flatter.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.11 no.5
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• pp.349-359
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• 1986

This paper is the basic research to identify automatically signals that are less than the bandwidth of 200Hz in shortwave band between 3 to 7 MHz and rarely appear. In order to do so, first, we describe the Detection and Estimation method of testing for the presence of absence about OOK signals of odB degree in 100KHz bandwidth. In the course of Detection and Estimation, it has decided the presence of OOK modulation Signal in additive noise to about 77% using LOD and E-C and about 90% using pattern model method of correlation function.

• MALSORI
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• no.58
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• pp.35-44
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• 2006

Maximum likelihood linear regression (MLLR) adaptation experiences severe performance degradation with very tiny amount of adaptation data. Eigenspace- based MLLR, as an alternative to MLLR for fast speaker adaptation, also has a weak point that it cannot deal with the mismatch between training and testing environments. In this paper, we propose a simultaneous fast speaker and environment adaptation based on eigenspace-based MLLR. We also extend the sub-stream based eigenspace-based MLLR to generalize the eigenspace-based MLLR with bias compensation. A vocabulary-independent word recognition experiment shows the proposed algorithm is superior to eigenspace-based MLLR regardless of the amount of adaptation data in diverse noisy environments. Especially, proposed sub-stream eigenspace-based MLLR with bias compensation yields 67% relative improvement with 10 adaptation words in 10 dB SNR environment, in comparison with the conventional eigenspace-based MLLR.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.4
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• pp.130-136
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• 2018

In this paper, the effects of different 3D printing parameters including laminated angle and annealing temperature, were observed for their effects on tensile testing. In 3D printing, a filament is heated quickly, extruded, and then cooled rapidly. Because plastic is a poor heat conductor, it heats and cools unevenly causing the rapid heating and cooling to create internal stress within the printed part. Therefore, internal stress can be removed using annealing and to increase tensile strength and strain. During air cooling at annealing temperature $140^{\circ}C$, the strain of laminated angle $45^{\circ}$ specimens tended to increase by 46% while the tensile stress tended to increase by 7.4%. During oven cooling at annealing temperature $140^{\circ}C$, the strain of laminated angle $45^{\circ}$ specimens tended to increase by 34% while the tensile stress tended to increase by 22.2%. In this study, we found "3D printing with annealing" eliminates internal stress and increases the strength and stiffness of a printed piece. On the microstructural level, annealing reforms the crystalline structures to even out the areas of high and low stress, which created fewer weak areas. These results are very useful for making 3D printed products with a mechanical strength that is suitable for applications.