• Korean Journal of Mathematics
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• v.30 no.3
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• pp.443-458
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• 2022

In this paper, we apply the concept of intuitionistic Q-fuzzy set to PMS-algebras. We study the concept of intuitionistic Q-fuzzy PMS-ideals of PMS-algebras and investigate some related properties of intuitionistic Q-fuzzy PMS-ideals of PMS-algebras. We provide the relationship between an intuitionistic Q-fuzzy PMS-subalgebra and an intuitionistic Q-fuzzy PMS-ideal of a PMS-algebra. We establish a condition for an intuitionistic Q-fuzzy set in a PMS-algebra to be an intuitionistic Q-fuzzy PMS-ideal of a PMS-algebra. Characterizations of intuitionistic Q-fuzzy PMS-ideals of PMS-algebras in terms of their level sets are given.

• Biomaterials and Biomechanics in Bioengineering
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• v.2 no.2
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• pp.111-125
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• 2015

For engineers, generating a mesh in porous media (PMs) sometimes represents a smaller computational load than generating realistic stent geometries with computer fluid dynamics (CFD). For this reason, PMs have recently become attractive to mimic flow-diverter stents (FDs), which are used to treat intracranial aneurysms. PMs function by introducing a hydraulic resistance using Darcy's law; therefore, the pressure drop may be computed by test sections parallel and perpendicular to the main flow direction. However, in previous studies, the pressure drop parallel to the flow may have depended on the width of the gap between the stent and the wall of the test section. Furthermore, the influence of parameters such as the test section geometry and the distance over which the pressure drops was not clear. Given these problems, computing the pressure drop parallel to the flow becomes extremely difficult. The aim of the present study is to resolve this lack of information for stent modeling using PM and to compute the pressure drop using several methods to estimate the influence of the relevant parameters. To determine the pressure drop as a function of distance, an FD was placed parallel and perpendicular to the flow in test sections with rectangular geometries. The inclined angle method was employed to extrapolate the flow patterns in the parallel direction. A similar approach was applied with a cylindrical geometry to estimate loss due to pipe friction. Additionally, the pressure drops were computed by using CFD. To determine if the balance of pressure drops (parallel vs perpendicular) affects flow patterns, we calculated the flow patterns for an ideal aneurysm using PMs with various ratios of parallel pressure drop to perpendicular pressure drop. The results show that pressure drop in the parallel direction depends on test section. The PM thickness and the ratio of parallel permeability to perpendicular permeability affect the flow pattern in an ideal aneurysm. Based on the permeability ratio and the flow patterns, the pressure drop in the parallel direction can be determined.

• Korean Journal of Community Nutrition
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• v.7 no.6
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• pp.731-740
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• 2002

This study was designed to identify premenstrual syndrome (PMS) and to investigate the correlation between premenstrual syndrome and nutritional intakes. The subjects of this study were 138 college women residing in Busan Metropolitan City. The subjects were asked to complete Menstrual Discomfort Questionnaire (MDQ) regarding PMS, food intake frequencies and nutritional intake. We studied the correlation between PMS symptoms and nutritional intake. The average height and weight of anemic subjects were 161.42 $\pm$ 3.50 cm and 51.87 $\pm$ 5.42 kg. The average BMI (body mass index, kg/$m^2$) was 19.92 $\pm$ 2.14 and PIBW (percent ideal body weight) were 93.02 $\pm$ 9.75%. Except for phosphorous, vitamin A and vitamin C intakes, the intake levels of all other nutrients were below the Korean RDA. The average calorie intake of the subjects was 1645.65 $\pm$ 352.63 kcal (82.2% of the Korean RDA) and iron intake of the subject was 11.06 $\pm$4.03 mg (69.1% of the Korean RDA) . The calcium and vitamin $B_6$ intakes were 512.26 $\pm$ 183.12 mg (73.1% of the Korean RDA) and 1.12 $\pm$ 0.14 mg (80.0% of the Korean RDA), respectively. With regard to their menstrual state, 45.9% subjects responded that their menstrual cycles were irregular. The frequency of PMS of the subjects was 30.2% (over 3 points) on 5 point scale (1 : no. 5 severe). The common symptoms of PMS of the subjects were pain (2.32 $\pm$ 1.01), negative effects (2.27 $\pm$ 0.87), behavioral changes (2.26 $\pm$ 0.85), water retention (2.07 $\pm$ 0.78) , arousal (1.79 $\pm$ 0.84) , autonomic reactions (1.77 $\pm$ 0.87) , lack of control (1.69 $\pm$ 0.75) and decreased concentration (1.68 $\pm$ 0.75) . There was significant correlation between all the PMS symptoms and calcium (p ＜ 0.01) , vitamin E (p ＜ 0.05) , carbohydrate (p ＜ 0.05) . This suggests that PMS represents the clinical manifestation of nutrient deficiency states especially calcium. Therefore we concluded that calcium supplementation is likely to be of benefit in relieving PMS symptoms.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.13-16
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• 2007

Fuel cell was used as a propulsion system for unmanned aerial vehicles (UAV) in the present study. Fuel cell propulsion system are an ideal alternative power source with high energy density for high-endurance UAV. Fuel cell power system provides UAV up to five times the energy densiη of existing batteries. Sodium borohydride, stored in liquid state, was selected as a hydrogen source. Hydrogen generation system consists of catalytic reactor, pump, fuel cartridge, and separator. Hybrid power management system (PMS) between fuel cell and lithium-polymer ba야ery was developed. Motor, pump, and fans， operated on battery power controlled by feedback signals of fuel cell system. Battery was recharged by surpuls powr of fuel cell.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.142.1-142.1
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• 2011

UBVI and $H{\alpha}$ CCD photometry of IC 1848, one of active star-forming regions in Cas OB6, is carried out as a part of Sejong Open cluster Survey (SOS) project. An OB association is an ideal laboratory for studying the triggered star formation and star formation history. Our purposes are to provide deep photometric data up to 21 mag in V and physical parameters of IC 1848. We classify 79 early-type stars and 186 pre-main sequence (PMS) stars as being the members of the cluster using photometric criteria. The IR excess emission PMS stars by Koenig et al. (2008) are also included as members of IC 1848. Total number of members is 414. We derive the interstellar reddening (=$0.659{\pm}0.058$ mag), reddening law ($R_V=4.0{\pm}0.1$), distance modulus ($V_0-M_V=12.0{\pm}0.1$ mag) using the early-type members of IC 1848. We also determine the age of the cluster ($3.5{\pm}1.5$ Myr) by placing the theoretical isochrones on the HR diagram.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.3B no.4
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• pp.179-187
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• 2003

In the machine tool industry, direct drive linear motor technology is of increasing interest as a means to achieve high acceleration and to increase reliability. This paper analyzes and compares the characteristics of the tubular linear actuator with the cylindrical Halbach and radial array, respectively. A tubular linear actuator with cylindrical Halbach array, consisting of parallel magnetized arc segments instead of ideal radial and axial magnetized rings, is manufactured. The magnetic field solutions due to the PMs and to the currents are established analytically in terms of vector potential, using the 2-D cylindrical coordinate system. Motor thrust, flux linkage and back emf are then derived. Thrust characteristics according to such design parameters as magnet height and air gap length are also given. The results are validated extensively by comparison with finite element analysis (FEA). Test results such as thrust measurements are also given to confirm the analysis.