• The Journal of Natural Sciences
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• v.10 no.1
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• pp.13-16
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• 1998

Every complex vector bundle over $S^1$ splits sum of line bundle and the first Chern class classify complex line bundle. This implies every complex vector bundle over $S^1$ is trivial. In this paper, we show the existence of some nontrivial complex vector bundle over $S^1$ in the equivariant case.

• Industrial Engineering and Management Systems
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• v.4 no.1
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• pp.36-46
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• 2005

In traditional production lines, such as assembly lines, each worker is usually assigned to a fixed task, which is beneficial since it reduces the amount of training needed for workers to master their assigned tasks. However, when workers complete their tasks at different speeds, the slowest worker will determine the overall pace of the production line and limit production. To avoid this problem, the self-balancing production line was introduced. In this type of production line, each worker works dynamically, thus they can maintain balanced production. Previous research analyzing the performance of these lines has ignored the walk-back time associated with dynamic workers. U-shaped production lines have also been analyzed and policies for such lines have been proposed. However, the walk-back time cannot be ignored in practice, and research taking this factor into account is needed to enable balanced production and thus the maximum production rate. In this paper, we propose production policies for a production line with the walk-back time taken into account, and define and analyze the conditions for self-balancing. Furthermore, we have compared the performance of such a line with that of other production lines under the same conditions, and the results show the superiority of this line in certain cases.

• Journal of electromagnetic engineering and science
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• v.4 no.3
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• pp.97-101
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• 2004

Complex permittivities of reference liquids were measured by a liquid holder of slotted coaxial line with a movable probe at mobile communication frequencies. The validity of the liquid measurement system was checked by experimental tests with the reference liquids proposed in IEEE Std. 1528-200X or IEC 106/61/CDV.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.12
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• pp.2167-2172
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• 2008

A large scale embedded generator or a micro-grid is usually interconnected to the grid through the dedicated line. Immediately after the removal of the grid supply, it must be disconnected and remain disconnected until the normal grid supplies are restored. This paper proposes an islanding detection algorithm based on complex power at the intertie. Complex power at the intertie delivered to the grid has a value depending on power flow during normal operation. When loss of mains occurs, complex power at the intertie moves to a value depending on the parameters of the dedicated line. The performance of the proposed algorithm was investigated under various operating and fault conditions. The proposed algorithm can detect an islanding operation even if no power is exchanged prior to loss of mains and discriminate the fault condition from islanding.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.9
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• pp.955-960
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• 2003

In this paper, complex permittivities of reference liquids were measured by a sample holder of terminated slotted coaxial line with a movable probe at mobile communications frequencies. The validity of the liquid measurement system was checked by experimental tests with the reference liquids proposed in IEEE Std 1528-200X.

• Korean Journal of Environmental Biology
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• v.22 no.1
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• pp.83-88
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• 2004

In order to investigate whether or not CCD-980sk cell line can be affected by Korean Citrus junos and medicinal herbs, we examined the MTT assay when we treated Korean Citrus junos and medicinal herbs in CCD-986sk human fibroblast cell line. The samples that added complex of grinded extracts of Korean Citrus junos and boiling-water extracts from Korean medicinal herbs were tested toy cell proliferation activity by means of a modification of the MTT assay. Among mixture of Citron 3 (Citron 3, less mellowed citron which was ripened for three months) and boiling-water extracts, the group Citron 3+Phellinus linteus showed significantly strong cell proliferation activity. And among mixture of Citron 4 (Citron 4, completely mellowed citron which was ripened for four months) and boiling-water extracts, the group Citron 4＋Cordyceps militaris and Citron 4+Phellinus linteus showed significantly strong cell proliferation activity, respectively. These results suggest that complex of Korean Citrus junos and medicinal herbs could be an excellent candidate toy protection of human skin aging.

• Archives of Plastic Surgery
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• v.32 no.6
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• pp.706-709
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• 2005

The absence of the nipple-areolar complex(NAC) in men are seldom stated, as a result of trauma, burn, mastectomy, or after the correction of extreme bilateral gynecomastia. A total of 50 healthy men aged 21 to 27 years were examined. We recorded the configuration (dimensions and shape) and the location of the NAC with respect to fixed skeletal anatomic landmarks. Of the 50 subjects examined, 44 had oval and 6 had a round NAC. The mean diameter for a round NAC was 24.3 mm. The center of the NAC was in the fourth intercostal space in 41 volunteers and in the fifth intercostal space in 9 of the subjects. To localize the NAC on the chest wall, at least three reproducible measurements proved to be necessary, composed of a horizontal line(distance from the midsternal line to the nipple, A), a medial oblique line(distance from the sternal notch to the nipple, B) and a lateral oblique line(distance from the acromioclavicular joint to the nipple, C). Using these three parameters, we recommend that the appropriate location can be calculated derived from the circumference of the chest.

• Korean Journal of Mathematics
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• v.7 no.1
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• pp.79-84
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• 1999

• Journal of the Korean Society for Precision Engineering
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• v.15 no.7
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• pp.91-97
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• 1998

The analysis model is the infinite body consisted of power law creep material containing a rigid inclusion with line crack shape subjected to the arbitrarily directional stress on an infinite boundary. The crack analysis is performed using the complex pseudo-stress function. The strain rate intensity factor is determined in the closed form as new fracture mechanics parmeter which represents the magnitudes of stress and strain rate near the tip in power law creep material.

• International Journal of Automotive Technology
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• v.8 no.3
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• pp.375-382
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• 2007

The multi-driver off-road vehicle drive-line consists of many components, with close connections among them. In order to design and analyze the drive-line efficiently, a modular methodology should be taken. The aim of a modular approach to the modeling of complex systems is to support behavior analysis and simulation in an iterative and thus complex engineering process, by using encapsulated submodels of components and of their interfaces. Multi-driver off-road vehicles are comparatively complicated. The driving-line is an important core part to the vehicle, it has a significant contribution to the performance. Multi-driver off-road vehicles have complex driving-lines, so performance is heavily dependent on the driving-line. A typical off-road vehicle's driving-line system consists of a torque converter, transmission, transfer case and driving-axles, which transfers the power generated by the engine and distributes it effectively to the driving wheels according to the road condition. According to its main function, this paper proposes a modularized approach for design and evaluation of the vehicle's driving-line. It can be used to effectively estimate the performance of the driving-line during the concept design stage. Through an appropriate analysis and assessment method, an optimal design can be reached. This method has been applied to practical vehicle design, it can improve the design efficiency and is convenient to assess and validate the performance of a vehicle, especially of multi-driver off-road vehicles.