• 전력전자학회논문지
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• 제10권1호
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• pp.87-94
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• 2005

본 논문은 저가형 고정도 아날로그 디지털 혼합형 엔코더에서 센서 취부 오차에 의해 발생하는 정지 2축 좌표상의 두 아날로그신호의 크기, 위상오차 문제 보상에 관한 연구이다. 기존의 혼합형 엔코더에서 문제시되고 있는 두 아날로그 위치정보 신호의 크기문제는 상대 크기에 대하여 정규화 함으로써 해결하였으며, 센서 취부시 발생하는 위치오차문제는 정지 2축 좌표축을 센서의 위치 오차분을 보상할 수 있도록 회전함으로써 보상할 수 있었다. 또한 제안된 새로운 방식의 위치 검출기법을 DSP의 QEP기능과 A/D변환기를 사용한 실험을 통하여 그 타당성을 검증하였다.

• International Journal of Contents
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• 제9권2호
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• pp.27-37
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• 2013

From the perspective of the domestic capital markets, there have been few researches on the financial characteristics of the firms belonging to the KOSDAQ(Korea Securities Dealers Automated Quotation) market, in comparison with those of the firms in the KOSPI. This study has performed three hypothesis tests to obtain the following results: By employing the 'panel data' analysis, it was found that, for the book-value based leverage, all of the six proposed IDVs were statistically significant as the financial determinants of leverage, across the two proxies measuring profitability (i.e., PFT and ROE), while all of the IDVs except VOLATILITY, also seemed to be the attributes to explain the market based dependent variable in the model with the PFT. Moreover, there may be statistically significant (structural) changes (or quasi-experiment) ) between the pre- and post-U.S. financial crisis in the year of 2008, when measured the leverage with the market-value basis with utilizing the Chow F-test. Finally, based upon the logistic regression results, the probability for a firm to be classified into the Prime section in the KOSDAQ market, may be higher, as its profit margin and asset turnover increase.

• Journal of Microbiology and Biotechnology
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• 제18권7호
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• pp.1335-1341
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• 2008

The cell wall material from fruiting bodies of Laetporus sulphureus has been suggested as a new alternative to mutan for the mutanase induction in Trichoderma harzianum. Structural analyses revealed that the cell wall fraction from this polypore fungus contained 56.3% of (1$\rightarrow$3)-linked $\alpha$-glucans. When the strain T. harzianum F-340 was grown on a cell wall preparation from L. sulphureus, the maximal enzyme productivity obtained after 3 days of cultivation was 0.71 U/ml. This yield was about 1.8-fold higher than that achieved on mutan, known so far as the best, but expensive and inaccessible, inducer of mutanase production. Cell-wall-induced mutanase showed a high hydrolytic potential in reaction with a dextranase-pretreated mutan, where maximal degrees of saccharification and solubilization of this biopolymer (80% and 100%, respectively) were reached in 3 h at 45$^{\circ}C$. The mutanase preparation was also effective in degradation of streptococcal mutan and its removal from oral biofilms, especially in a mixture with dextranase.

• 한국자동차공학회논문집
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• 제6권6호
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• pp.155-165
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• 1998

The resistance coefficient and heat transfer performance are studied for the turbulent water flow in a smooth coiled tube having variable curvature ratios and a corrugated-coiled tube having a ratio of coil to tube diameter of 22. Experiments are carried out for the fully developed turbulent flow of water in tube coils on the uniform wall temperature condition. This work is limited to tube coils of R/a between 22 and 60 and Reynolds numbers from 13000 to 53000. The tube having a ratio of coil to tube diameter of 27 among the 3 smooth tube coils shows the best heat transfer performance. A corrugated-coiled tube(R/a=60) shows more excellent performance than a smooth coiled tub (R/a=60) at a similar curvature ratio. The friction factor f is sensitive to changes in the velocity profile caused by a temperature gradient. Allowance was made for the pressure loss in the short inlet and outlet lengths and due to the presence of the thermocouple inlet and outlet as a result of separate experimental on a straight tube. It is to be expected that the allowance at the exit will be somewhat too low because of secondary flow effects carried over from the coil.

• Macromolecular Research
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• 제10권6호
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• pp.332-338
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• 2002

The effect of an electron beam and ${\gamma}$-ray irradiation on the curing of epoxy resins was investigated. Diglycidyl ether of bisphenol A (DGEBA) and diglycidyl ether of bisphenol F (DGEBF) as epoxy resin were used. The epoxy resins containing 1.0-3.() wt% of triarylsulphonium hexafluoroantimonate(TASHFA) and triarylsulphonium hexafluorophosphate(TASHFP) as initiator were irradiated under nitrogen at room temperature with different dosage of EB and ${\gamma}$-rays from a Co$^{60}$ u source. The chemical and mechanical characteristics of irradiated epoxy resins were compared after curing of EB and ${\gamma}$-ray irradiation. The thermal properties of cured epoxy were investigated using dynamic mechanical thermal analysis. The chemical structures of cured epoxy were characterized using near infrared spectroscopy. Mechanical properties such as flexural strength, modulus were measured. The gel fraction of DGEBA with ${\gamma}$-ray was higher than that of the epoxy with EB at the same dose. Young's modulus of the sample irradiated by ${\gamma}$-ray is higher than that of sample cured by EB. From the result of strain at yield, it was found that the epoxy cured by ${\gamma}$-ray had a higher stiff property compared with the irradiated by EB.

• 한국표면공학회지
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• 제32권3호
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• pp.467-471
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• 1999

BN films were grown on silicon (l00) substrate by magnetically enhanced activated reactive evaporation (ME-ARE) with pulsed DC power instead of r.f. for substrate biasing. The deposited films were analyzed using Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). FTIR results show that the intensity of absorption band of $sp^2$ bond of BN decreased and that of $sp^3$ bond of c-BN increased with increasing pulsed DC bias voltage applied to substrate. The initially grown layer at the interface was observed by TEM and considered to be of$ sp^2$-bonded BN. The cross-sectional and planar TEM micrographs show that the upper layer on the initial layer was the single phase c-BN. It is concluded that cubic boron nitride films could be synthesized by ME-ARE process with pulsed DC biasing.

• Nuclear Engineering and Technology
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• 제39권4호
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• pp.287-298
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• 2007

As part of the $AP1000^{TM}$ pressurized water reactor design certification program, a series of integral systems tests of the nuclear steam supply system was performed at the APEX-1000 test facility at Oregon State University. These tests provided data necessary to validate Westinghouse safety analysis computer codes for AP1000 applications. In addition, the tests provided the opportunity to investigate the thermal-hydraulic phenomena expected to be important in AP1000 small-break loss of coolant accidents (SBLOCAs). The APEX-1000 facility is a 1/4-scale pressure and 1/4-scale height simulation of the AP1000 nuclear steam supply system and passive safety features. A series of eleven tests was performed in the APEX-1000 facility as part of a U.S. Department of Energy contract. In all, four SBLOCA tests representing a spectrum of break sizes and locations were simulated along with tests to study specific phenomena of interest. The focus of this paper is the SBLOCA tests. The key thermal-hydraulic phenomena simulated in the APEX-1000 tests, and the performance and interactions of the passive safety-related systems that can be investigated through the APEX-1000 facility, are emphasized. The APEX-1000 tests demonstrate that the AP1000 passive safety-related systems successfully combine to provide a continuous removal of core decay heat and the reactor core remains covered with considerable margin for all small-break LOCA events.

• Journal of Smart Tourism
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• 제1권1호
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• pp.53-64
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• 2021

Upselling is often a critical factor in revenue generation for businesses in the tourism and travel industry. Utilizing passenger data from a major international airline company, we develop the PAX (Passenger, Airline, eXternal) model to predict passengers that are most likely to accept an upgrade offer from economy to premium. Formulating the problem as an extremely unbalanced, cost-sensitive, supervised binary classification, we predict if a customer will take an upgrade offer. We use a feature vector created from the historical data of 3 million passenger records from 2017 to 2019, in which passengers received approximately 635,000 upgrade offers worth more than $422,000,000 U.S. dollars. The model has an F1-score of 0.75, outperforming the airline's current rule-based approach. Findings have several practical applications, including identifying promising customers for upselling and minimizing the number of indiscriminate emails sent to customers. Accurately identifying the few customers who will react positively to upgrade offers is of paramount importance given the airline 'industry's razor-thin margins. Research results have significant real-world impacts because there is the potential to improve targeted upselling to customers in the airline and related industries.

• 한국임상보건과학회지
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• 제6권2호
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• pp.1106-1114
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• 2018

Purpose: This study was conducted to identify factors influencing the weight control behavior of female college students. Method: The subjects included female college students in the U City area, and data were collected through a self reported structured questionnaire from July 01 to 28 of 2017. Totally 220 subjects were analyzed. Analyses consisted of descriptive statistics, ANOVA, Pearson's correlation analysis, and stepwise multiple regression analysis. Results: The findings showed dissatisfaction of female college students' perceptions of their bodies based on BMI, body satisfaction and obesity stress, which had special impacts on their weight control behaviors. Weight control behaviors was closely influenced by obesity stress (${\beta}=.848$, p<.001) accounted for 48.7% of the weight control behaviors (F=71.97, p<.001). Conclusion: These findings indicate that it is necessary to develop and implement information programs and design appropriate prevention programs that can induce healthy weight control behaviors. Such programs should include health education, as well as intervention programs to identify such predictors and help college students judge and perceive positive body image so that they control their weight in a proper manner.

• Nuclear Engineering and Technology
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• 제51권1호
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• pp.116-124
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• 2019

$M^2LFR-1000$ is a medium-power modular lead-cooled fast reactor, developed by University of Science and Technology of China (USTC), aiming at achieving a reactor design fulfilling the Gen IV nuclear system requirements and meanwhile emphasizing the optimum safety and economics. In order to evaluate the safety performance of $M^2LFR-1000$ reactor core, three typical transients are selected from initiating events, which are unprotected transient overpower (UTOP), unprotected loss of offsite power (ULOHS+ULOF) and increase of feedwater flowrate with primary pumps trip (IFW+PLOF). These three transients presented and discussed in this paper are performed with the code Analysis of THermal-hydraulics of LEaks and Transients (ATHLET), which is developed by Gesellschaft $f{\ddot{u}}r$ Anlagen-und Reaktorsicherheit gGmbH (GRS). The results indicate that the $M^2LFR$ is safe enough under these three transients due to the good inherent safety features of the reactor, without human intervention, the reactor will reach a new steady state under UTOP condition.