• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.7
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• pp.1124-1128
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• 2021

As regulations of emissions from ships become more stringent, electric propulsion systems have been increasingly used to solve this problem in vessels ranging from large merchant ships to small and medium-sized ships. Methods for improving the efficiency of the electric propulsion system include the improvement of power sources; the use of a system linked to environmentally friendly power sources, such as batteries, fuel cells, and solar power; and the development of hardware and control methodology for rectifiers, power conversion devices, and propulsion motors. The method using a phase-shifting transformer with diodes has been widely used for rectification. Power semiconductor devices with grid connection to an environmentally friendly power source using DC distribution, a variable speed power source, and the application of small and medium-sized electric propulsion systems have been developed. Accordingly, the demand for active front-end (AFE) rectifiers is increasing. In this study, a method using a neural network rather than a conventional proportional-integral controller was proposed to control the AFE rectifier. Tested controller data were used to design a neural network controller trained through MATLAB/Simulink. The neural network controller was applied to a rectification system designed using PSIM software. The results indicated the effectiveness of improving the waveform and power factor DC output stage according to the load variation. The proposed system can be applied as a rectification system for small and medium-sized environmentally friendly ships.

• Asia pacific journal of information systems
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• v.21 no.2
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• pp.59-87
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• 2011

These days, firms are focusing on the improvement of relationships with business partners. The supply chain integrations are taking critical role in improving the relationships with business partners. In accordance with the development of the IT technology, it became possible for firms not only to integrate inner parts of the organization, but also to integrate the company with other organizations in the supply chain. Therefore, in e-Biz environments, it is imperative for firms to strengthen the core capacity through the supply chain, and to precisely determine the components of the determinants of e-Business integration which impact the firm performance. This study analyzed determinants that have impacts on e-business integration in e-business capacity perspectives in competitive environments. This study based on the premise that the resources and capacities that Grant(1991) and Hart(1995) emphasized do not directly influence the corporate performance. This study focused on the fact that corporate must create core competencies based on these capacities to establish competitive edge. Therefore, this study model analyzed to find out which e-Biz competencies are needed to integrate e-Biz according to competitive environment elements. This study designed to empirically analyze the impact of the e-Biz competencies to the e-Biz integration and to the corporate performance. Independent variables of this study-IT management, partner management, e-Biz knowledge, e-Biz establishment and proliferation, process innovation-are selected based on precedent studies on e-Biz competencies. We selected intermediate variables to verify that e-Biz competencies do not have direct impact on the corporate performance, but have impact on the e-Biz integration, which is intermediate effect. That is to verify that if the components of supply chain improve the integration level using e-Biz competencies, the overall supply chain performances will improve. Dependent variables are selected to verify that e-Biz integration has impacts on corporate performances. This study used factor analysis, path analysis, moderating effect analysis as statistical tests. First, we used exploratory factor analysis and confirmatory factor analysis to analyze reliability and validity. Because e-Biz competencies are presented variously by preceding studies, we used SPSS16.0 to verify if survey questionnaire used by theoretical backgrounds is properly composed. Second, we tested the property of structure model by AMOS. We did path analysis using AMOS16.0 to test structure that is composed of e-Biz competencies and e-Biz integration. Last, we tested moderating effects of measure factors. We analyzed 163 domestic companies to find out many significant suggestive points. First, relationship improvement capacity, e-business knowledge sharing capacity with business partners, and process innovation capacity are adopted as determinants of differentiation and competitive edges against competing firms. Second, e-business knowledge sharing capacity, and process innovation capacity are analyzed as the determinants of e-business integration in the firm which demand fluctuation in the market is high. On the other hand, among the determinants that require capturing ideas on new products, and strengthening the technological power, process innovation capacity are adopted as the determinants. These results provide us the foundation that the determinants that we have analyzed can impact the supply chain integration strategies which take into account the competitive environments.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.2
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• pp.108-116
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• 2014

With the increasing the importance of emotional quality of vehicle, the sound quality of systems with electric motor components has become increasingly important. Electric motors are used for windows, seats, sun roof, mirrors, steering columns, windshield wiper and climate control blowers, etc. In this paper, a study was conducted to identify sound quality factors that contribute to customer's satisfaction and preference of the window lift system. Jury test for subjective evaluation was carried out and sound quality index was developed. Averaged sound pressure level and sharpness were significant factors when glass moves down. Also, maximum loudness at stop section and averaged loudness were significant factor when glass moves up. Next, noise source identification was carried out using beam forming method during glass transferred section and impulsive noise at stop section. Several improvement methods were applied using the source identification result. And finally, the degree of sound quality improvement was judged using sound quality index.

• Korean Chemical Engineering Research
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• v.48 no.4
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• pp.457-461
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• 2010

After the industrial revolution, quantity production system has made the life of mankind rich and to fulfill the consumer's desire competitive power of the enterprise constantly make has made effort in quality, price and engineering department not remaining simple manufactures. But in such a change production lacked safety. Consequently, the main study studied in return domestic organization which produces a chemistry fiber rope to be used fact vessel or as a athletic equipment safety countermeasure. One of the assesment method on product liability, Checklist is showed that It can be used not as an evaluation but as a development factor of company. Also, checklist that used a study could expect that assist the company of management structure as well as improvement of product safety.

• The Journal of the Acoustical Society of Korea
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• v.23 no.8
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• pp.583-589
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• 2004

Proposed is a speaker normalization method based on vector quantizer for continuous speech recognition (CSR) system in which no acoustic information is made use of. The proposed method, which is an improvement of the previously reported speaker normalization scheme for a simple digit recognizer, builds up a canonical codebook by iteratively training the codebook while the size of codebook is increased after each iteration from a relatively small initial size. Once the codebook established, the warp factors of speakers are estimated by comparing exhaustively the warped versions of each speaker's utterance with the codebook. Two sets of phones are used to estimate the warp factors: one, a set of vowels only. and the other, a set composed of all the Phonemes. A Piecewise linear warping function which corresponds to the estimated warp factor is adopted to warp the power spectrum of the utterance. Then the warped feature vectors are extracted to be used to train and to test the speech recognizer. The effectiveness of the proposed method is investigated by a set of recognition experiments using the TIMIT corpus and HTK speech recognition tool kit. The experimental results showed comparable recognition rate improvement with the formant based warping method.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.10
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• pp.5189-5193
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• 2012

Kemerovo is an industrial region of the Russian Federation characterized by highly developed mining, chemical, metallurgical and power industries. Many of the factories were closed down due to the socioeconomical crisis in the early 90's, and economic potential of the survivors has also decreased significantly. Paradoxically, this has led to the improvement of the ecological situation in the region and elimination of exposure to many chemical carcinogens. This factor, in combination with the improvement of oncological care, might be expected to have lead to a decline of cancer incidence and mortality in the region. To assess trends of cancer incidence and mortality in Kemerovo Region, we therefore carried out an analysis of relevant epidemiological data during 1991-2010. In fact, a significant increase of cancer incidence overall was revealed during 2001-2010. Male cancer incidence was significantly higher than female cancer incidence. Regarding gastric cancer incidence, statistically significant differences during 2001-2010 were found only for men, and male incidence exceeded female incidence. Concerning colorectal cancer incidence, it was lower during 2001-2005 and 2006-2010 as compared to the period of 1991-1996. Lung cancer incidence was significantly higher during 1991-2000 compared to 2001-2010. Among urban populations, cancer incidence was higher in comparison with rural population, but a gradual steady convergence of trends of cancer incidence among urban and rural populations was noted. Lung cancer, breast cancer, colorectal cancer, non-melanoma skin cancer, and gastric cancer are the most prevalent cancer forms in Kemerovo Region. There were no differences in cancer mortality between 2001-2005 and 2006-2010; however, male cancer mortality exceeded female cancer mortality. A similar situation was observed for gastric cancer, colorectal cancer, and lung cancer. Cancer mortality among urban populations exceeded mortality among rural population, for both genders. We suggest that these data can be used for development of modern programs of cancer prevention and early diagnostics in industrial regions of Siberia.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.53 no.4
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• pp.446-455
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• 2017

The improvement of resistance performance for the 4.99 ton class fishing boats was shown. The 4.99 ton fishing boats are the most commonly used one in the Korean coastal region. The evaluation of resistance performance was estimated by the Computational Fluid Dynamics (CFD) analysis. The CFD simulation was performed by the validation for various types of bow shapes on the hull. The optimized hull form from the simulation was selected and showed the best resistance performance. This hull type was tested on the towing tank in the National Institute of Fisheries Science (NIFS). The effective horsepower (EHP) was estimated by the resistance test on the towing tank with the bare hull condition. The drag force on the three service speed conditions was obtained for the resistance analysis to power prediction. The measured drag forces are compared with the results from the CFD simulation with one another. As results of the model tests, it was confirmed that the shape of the bow is an important factor in the resistance performance. The effective horsepower decreased about 30% in comparison with the conventional hull form. Also, the resistance performance improved the reduction of required horsepower, which especially contributed to the energy-saving for the fisheries industry. In the CFD analysis, the resistance performance improved slightly. In this case, the ratio of the residual resistance ($C_R$) in the total resistance ($C_T$) was high. Therefore, the CFD analysis was not enough to satisfy with reflection for the free surface and wave form in the CFD procedure. Both model test and CFD calculation in this study can be applied to the initial design process for the coastal fishing vessel.

• Journal of the Korean earth science society
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• v.38 no.1
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• pp.11-23
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• 2017

The short term predictability of wind resources is an important factor in evaluating the economic feasibility of a wind power plant. As a method of improving the predictability, a Bayesian Kalman filter is applied as the model data postprocessing. At this time, a statistical training period is needed to evaluate the correlation between estimated model and observation data for several Kalman training periods. This study was quantitatively analyzes for the prediction characteristics according to different training periods. The prediction of the temperature and wind speed with 3-day short term Bayesian Kalman training at Taebaek area is more reasonable than that in applying the other training periods. In contrast, it may produce a good prediction result in Ieodo when applying the training period for more than six days. The prediction performance of a Bayesian Kalman filter is clearly improved in the case in which the Weather Research Forecast (WRF) model prediction performance is poor. On the other hand, the performance improvement of the WRF prediction is weak at the accurate point.

• Journal of Digital Convergence
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• v.17 no.3
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• pp.161-168
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• 2019

The purpose of this study analyze consumer usage characteristics and product development guide of electronic pen based on TAM theory(Davies, 1989). Research methods apply contents analysis(qualitative research) and Activity/Inactivity analysis of main consumer participation. Research results are as follows. Active consumer indicated 30-49 age, male, office job and research fellow. And they suggested stable power supply system, App connected pen function extension, add the modified pen function, advanced data recognition of pen, advanced take note ability and stable grip feeling of pen, selected line width, synchronization improvement with other smart device and charging function. These result indicated the importance product improvement diffusion factor of early market to main market. The future research of electric pen focused on different product strategy between electric pen and smart device connected electric pen.

• Proceedings of the IEEK Conference
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• 2004.06a
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• pp.213-216
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• 2004

This paper describes design and implementation of the 5.5 GHz VCO with parallel-branch inductors using 0.8${\mu}m$ SiGe HBT process technology. The proposed parallel-branch inductor shows $12 \%$ improvement in quality factor in comparison with the conventional inductor. A phase noise of -93 dBc/Hz is measured at 100 kHz offset frequency, and the harmonics in the VCO are suppressed less than -23 dBc. The single-sided output power of the VCO is -6.5$\pm$1.5 dBm. The manufactured VCO consumes 15.0 mA with 2.5 V supply voltage. Its chip areas are 1.8mm ${\times}$ 1.2mm.