• Journal of the Korean Society for Precision Engineering
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• v.17 no.8
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• pp.157-164
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• 2000

This paper presents a method to detect a rotor position and to drive a BLDC motor from standstill to medium speed without any position sensor comparing the current responses due to the inductance variation in the rotor position. A rotor position at a standstill is identified by the current responses of six pulses injected to each phase of a motor. Once the motor stars up pulse train that is composed of long and short pulses is injected to the phase corresponding to produce the maximum torque and the next phase continuously. it provides not only the torque but also the information of the next commutation time effectively when the response of long and short pulses crosses each other after the same time delay. This method which is verified experimentally using a DSP can drive a BLDC motor to the medium speed smoothly without any rattling and time delay compared with the conventional sensorless algorithm.

• Journal of Preventive Medicine and Public Health
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• v.33 no.4
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• pp.415-425
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• 2000

Objectives : To determine which factors are related to young adults perception of their health. Two research questions were asked. Which aspects of health does self-perceived health as a index of general health reflect? Why do two individuals with the same level of general health have different health perceptions? Methods : The sampling frame comprised college or graduate school students, aged 20 to 29, who were members of A, one of the 4 biggest internet communication services. The questionnaires were sent to study samples(n=1,000) and answered by E-mail. Response rate was 37.0%. Results : Firstly, physical health ranked highest and self-perceived health ranked lowest. Secondly, health, anxiety, depression, and self-perceived health showed significant differences between the sexes, with women showing a higher health status in these categories except for self-perceived health. Thirdly, the two factors significantly related to self-perceived health were physical health and self-esteem, as determined by multivariate analysis, Conclusions : The factors significantly related to self-perceived health were physical health and self-esteem. Further studies of the health characteristics of young adults are needed.

• Journal of the Korean Society of Food Culture
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• v.15 no.2
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• pp.69-78
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• 2000

The purposes of this study were to : (a) investigate overall operating conditions of university residence hall foodservice, (b) compare them by the management systems. Questionnaires were hand delivered and mailed to 73 foodservice managers. A total of 56 were usable; resulting in 76.7% response rate. The survey was conducted between October, 1998 and May, 1999. Statistical data analysis was completed using the SAS/Win 6.12 for Descriptive Analysis, $x^2-test$. Sixty-four percent of the foodservice operations were 'self-operated'; 23% were 'contracted'; and 13% were 'rented'. Eighty-three percent of operations provided 'single menu'; forty-six percent of foodservice operations with 'partially self-service'; and forty-one percent with 'complete self-service'. Forty-four percent of overall foodservice operations provided 1,000-2,000 meals per day; thirty-one percent provided less than 1,000 meals per day, and twenty-four percent provided more than 2,000 meals per day. The highest meal price was 1,950 won and the lowest was 700 won with average of 1,295 won. The mean number of employees was 12.2; the number of working hours was 59.7 hours per week.

• Journal of fish pathology
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• v.13 no.2
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• pp.103-110
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• 2000

The immunostimulatory effects of quaternary ammonium compounds(QACs) were investigated in leucocytes of eel(Anguilla japonica) in vitro. Proliferation of peripheral blood lymphocytes(PBLs) was no significantly affected by QACs, regardless of mitogen(PHA, ConA and LPS) and the concentration of QACs added. QACs heightened the leucocytes function such as respiratory burst activity, phagocytosis and pinocytosis, resulting in significantly increased the bactericidal activity of macrophages. These results suggested that QAC might modulate the immune responses by activation of leucocytes function but not by increment of immunocompetent cell numbers.

• Journal of Nutrition and Health
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• v.33 no.5
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• pp.491-496
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• 2000

Food intake is regulated by both central and peripheral mechanisms. In the central nervous, the hypothalamus acts for autonomic and endocrine homeostasis. The paraventricular nucleus(PVN) of hypothalamus is an imprtant site of interaction in central feeding pathways. Neuroepetide Y(NPY)is one of the most powerful neurochemical stimulants of food intake known. Also brain nitric oxide(NO), known as neurotransmitter, is involved in the mechanisms that regulate food intake. In this experiment, 24h fasting mice and anorexia mutant mice have been to examine the expression of NPY, which is the major neuropeptide increasing food intake. Double staining with NPY and nicotinamide-adenine-dinucleotide-phosphate diaphorase(NADPH-d), followed by immunohistochemical method and image analysis, have been used to observe coexisting neurons and the level of expression of each neurons. The results were as follows. 1) NPY-immunoreactivitys reduced immune response of the hypothalamus, particularly paraventricular nucleus(PVN), in anorexia mutant mice. Decreased level of NPY is assumed to be a major pathological factor in anorexia mutant mice. On the other hand, PVN in hypothalamus of fasting mice showed increased immunoreactivity which is in agreement of other researchers. 2) NPY and NADPH-d double staining revealed coexisting neurons in the cerebral cortex. Fasting mice had a tendency to have increased level of coexisting neurons compared to the control group. Compared to the control group, fasting mice express is not increase level of NPY-immunoreactivity, while anorexia mutant mice tended to have a decreased level.

• Journal of KIISE:Software and Applications
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• v.27 no.8
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• pp.795-803
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• 2000

This paper presents a shared data decomposition model for improving concurrency in multi-user, distributed software developments. In our model, the target software system is decomposed into the independent components based on project roles to be distributed over clients. The distributed components are decomposed into view objects and core objects to replicate only view objects in a distributed collaboration session. The core objects are kept in only one client and the locking is used to prevent inconsistencies. The grain size of a lock is a role instead of a class which is commonly used as the locking granularity in the existing systems. The experimental result shows that our model reduces response time by 12${\sim}$18% and gives good scalability.

• Restorative Dentistry and Endodontics
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• v.25 no.2
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• pp.159-169
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• 2000

The purpose of this study was to examine the tissue response to experimental furcation perforations immediately treated with Super EBA, Ketac Silver, MTA and Emdogain using surgical microscope. Forty experimental furcation perforations were created in the mandibular and maxillary premolars and molars of 4 adult dogs and immediately repaired with experimental materials. The animals were sacrificed after 16 weeks and radiographic and histologic results were evaluated. The results were as follows. 1 All materials tested in this experiment revealed a certain degree of extrusion of the filling materials and infiltration of inflammatory cells into the periodontal space. Except MTA group, epithelial down-growth of the surrounding gingiva was found in all experimental groups. 2. Both Ketac Silver and Emdogain group showed the greatest degree of inflammatory reaction and bone resorption. 3. Super EBA group showed moderate inflammation and newly bone formation under the perforation area. 4. MTA group showed minor inflammation, new bone regeneration toward restorative materials and partially cementum growth onto the surface of the material. This group demonstrated a favorable prognosis.

• Journal of The Korean Astronomical Society
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• v.33 no.1
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• pp.1-17
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• 2000

We have performed extensive simulations of response of gaseous disk in barred galaxies using SPH method. The gravitational potential is assumed to be generated by disk, bulge, halo, and bar. The mass of gaseous disk in SPH simulation is assumed to be negligible compared to the stellar and dark mass component, and the gravitational potential generated by other components is fixed in time. The self-gravity of the gas is not considered in most simulations, but we have made a small set of simulations including the self-gravity of the gas. Non-circular component of velocity generated by the rotating, non-axisymmetric potential causes many interesting features. In most cases, there is a strong tendency of concentration of gas toward the central parts of the galaxy. The morphology of the gas becomes quite complex, but the general behavior can be understood in terms of simple linear approximations: the locations and number of Lindblad resonances play critical role in determining the general distribution of the gas. We present our results in the form of 'atlas' of artificial galaxies. We also make a brief comment on the observational implications of our calculations. Since the gaseous component show interesting features while the stellar component behaves more smoothly, high resolution mapping using molecular emission line for barred galaxies would be desirable.

• YAKHAK HOEJI
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• v.44 no.2
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• pp.135-140
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• 2000

Determination of Aconitum alkaloids in processed Buza (Cho-0, Salted Buza, Moist-heating Buza, Limed Buza), which had been prepared from the raw tubers of Aconitum chiisanenseb(Ranunculaceae), was established using visible spectrophotometry and high-performance liquid chromatography (HPLC) method especially for Aconitine analysis. Aconitum alkloids were reacted with tetra- thiocy-anatocobalt[II] complex ion to form a stable ion pair. The reaction product was insoluble in water but freely soluble in several organic solvents. 1.2-Dichloroethane was the best extracting solvent among the examined solvents. Spectrophotometry of Aconitum alkaloids at nax. 625 was carried out. The HPLC method for aconitine was carried out using Radial PAK-CN column with gradient solvent system by solvent mixture of acetonitrile and phosphate buffer (pH 3.0) at 4$0^{\circ}C$ and 254 nm. Linear relationship was found between absorbance response and concentration of aconitine in range of 0.45 mM~0.9 mM ($r^2$=0.9949) by spectrophotometry and 0.3 mM~1.2mM($r^2$=0.9983) by HPLC method. These methods have been found to be suitable and reproducible for routine analysis of Aconitum alkaloids and its pharmaceutical preparations.

• Advances in concrete construction
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• v.8 no.2
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• pp.145-154
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• 2019

The present experimental study addresses the structural response of reinforced concrete (RC) beams strengthened in shear. Thirteen RC beams were divided into four different sets to investigate the effect of transverse and longitudinal steel reinforcement ratios, concrete compressive strength change and orientation for installing carbon fiber-reinforced polymer (CFRP) laminates. Then, we employed a shear strengthening solution through externally bonded reinforcement in grooves (EBRIG) and externally bonded reinforcement (EBR) techniques. In this regard, rectangular beams of $200{\times}300{\times}2000mm$ dimensions were subjected to the 4-point static loading condition and their load-displacement curves, load-carrying capacity and ductility changes were compared. The results revealed that using EBRIG method, the gain percentage augmented with the increase in the longitudinal reinforcement ratio. Also, in the RC beams with stirrups, the gain in shear strength decreased as transverse reinforcement ratio increased. The results also revealed that the shear resistance obtained by the experimental tests were in acceptable agreement with the design equations. Besides, the results of this research indicated that using the EBRIG system through vertical grooves in RC beams with and without stirrups caused the energy absorption to increase about 85% and 97%, respectively, relative to the control.