• 한국경영정보학회:학술대회논문집
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• 한국경영정보학회 2007년도 International Conference
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• pp.576-581
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• 2007

The purpose of this paper is to strengthen trust on the automated collaborative filtering system. Automated collaborative filtering system is quickly becoming a popular technique for recommendation system. This elaborative methodology contributes for reducing information overload and the result becomes index of users' preference. In addition, it can be applied to various industries in various fields. After it collaborative filtering system was developed, many researches are executed to enhance credibility and to apply in various fields. Among these diverse systems, collaborative filtering system which uses Pearson correlation coefficient is most common in many researches. In this paper, we proposed new process diagram of collaborative filtering algorithm and new factors which should improve the credibility of system. In addition, the effects and relationships are also tested.

• 천문학회지
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• 제24권1호
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• pp.117-127
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• 1991

Here I report the confirmation of a long-term modulation of a period of $92^{+21}_{-13}$ years with the "time-delay correlation" method on the sunspot data compiled over the last a total of 289 years. This periodicity better specifies the cycle which falls pretty well within Gleissberg cycle, and clearly contrasts with the 55 year grand cycle which Yoshimura (1979) claimed. It is argued that the period-amplitude diagram method. which Yoshimura used, ana lysed peak amplitudes only so that a large number of data were disregarded, and thus was more susceptible to a bias. The planetary tidal force on Sun as for the possible cause to the solar activity was investigated and its possibility was ruled out in view of no period correlation between them.

• 한국연초학회지
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• 제4권1호
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• pp.37-42
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• 1982

Korean local and introduced varieties were classified by the cluster analysis of correlation and taxonomic distance based on nineteen growth characters. 1. Thirty six varieties can be classified into three groups(I, II, III) by WVGM (weighted variable group method) 2. Major characters for classifying cultivars were days to flowering, number of leaves, leaf length, stem diameter and width of midrib: the five characters seemed to be useful in monothetic classification. 3. Korean varieties were similar to oriental, and japanese varieties to taiwan. 4. WVGM was more accurate and meaningful than classification by WPGM (weighted paired group method) and reticulate diagram of correlation. 5. Characteristics of each group: Group I closely related to many leaves, late of maturity and broad leaf type, Group II related to medium leaves, late of maturity and narrow leaf type, Croup 19 related to few leaves, early of maturity and medium leaf type respectively.

• International Journal of Naval Architecture and Ocean Engineering
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• 제11권1호
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• pp.624-637
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• 2019

A semi-submersible offshore platform always operates under complex weather conditions, especially wind and waves. It is vital to analyze the structural dynamic responses of the platform in short-term sea states under the combined wind and wave loads, which touches upon three following work. Firstly, a derived relationship between wind and waves reveals a correlation of wind velocity and significant wave height. Then, an Improved Mixture Simulation (IMS) method is proposed to simulate the time series of wind/waves accurately and efficiently. Thus, a wind-wave scatter diagram is expanded from the traditional wave scatter diagram. Finally, the time series of wind/wave pressures on the platform in the short-term sea states are converted by Workbench-AQWA. The numerical results demonstrate that the proposed numerical methods are validated to be applicable for wind and wave simulations in structural analyses. The structural dynamic responses of the platform members increase with the wind and wave strength. In the up-wind and wave state, the stresses on the deck, the connections between deck and columns, and the connection between columns and pontoons are relatively larger under the vertical bending moment. These numerical methods and results are wished to provide some references for structural design and health monitoring of several offshore platforms.

• 대한기계학회논문집A
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• 제26권8호
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• pp.1645-1652
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• 2002

The failure analysis on fractured parts is divided into the qualitative method by naked eyes and metallurgical microscope etc. and the quantitative method by SEM and X-ray diffraction etc. X-ray fractography can be applied to contaminated surface as well as clean surface and gain the plastic deformation and the residual stress near the fractured surface. Turbine blade is subject to cyclic bending force by steam pressure and suffers fatigue damage according to the increasing operating time. Therefore, to clean up the fracture mechanism of torsion-mounted blade in nuclear plant, the fatigue and the X-ray diffraction test was performed on the 12%Cr steel fur turbine blade and the fractured parts. The correlation of X-ray parameter and fracture mechanics parameter was determined, and then the load applied to actual broken turbine blade was predicted. Failure analysis was performed by contact stress analysis and Goodman diagram of torsion-mounted blade.

• 천문학회보
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• 제41권2호
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• pp.44.2-45
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• 2016

We present near-infrared photometric properties of red supergiant stars (RSGs) in three galaxies NGC 4449, NGC 5055 and NGC 5457. The near-infrared imaging data of WFCAM UKIRT were used and combined with optical archive data to identify the RSGs in the galaxies. We found that the RSGs can be identified from the foreground Galactic stars in (i-K, ri) colour-colour diagram. The effective temperatures and luminosities of the identified RSGs are estimated from JHK photometry using MARCS model. In the H-R diagram, the majority of RSGs in the galaxies are distributed between $logL/L{\odot}=4.8$ and 5.7, and their effective temperature and luminosities agree with the current evolutionary tracks with masses in the range $9-30M{\odot}$. We also compared the spatial distribution of RSGs with the HII regions. A tight spatial correlation between RSGs and HII region was found in NGC 4449 and NGC 5457. We do not find a clear metallicity dependance on the RSG effective temperature in the three galaxies, but the maximum luminosity of the three galaxies is constant at $logL/L{\odot}{\sim}5.6$. Additional spectroscopy data, including photometry are essential to examine whether the physical properties of RSGs change with metallicity.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.258-265
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• 2001

Turbine blade is subject to force of three type ; torsional force by torsion-mount, centrifugal force by rotation of rotor and cyclic bending force by steam pressure. Cyclic bending force of them is main factor on fatigue fracture. In the X-ray diffraction method, the change in the values related to plastic deformation and residual stress near the fracture surface mat be determined, and information of internal structure of material can be obtained. Therefore, to find a fracture mechanism of torsion-mounted blade in nuclear plant, based on the information from the fracture surface obtained by fatigue test, the correlation of X-ray parameter and fracture mechanics parameter was determined, and then the load applied to actual broken turbine blade parts was predicted. Failure analysis is performed by finite element method and Goodman diagram on torsion-mounted blade.

• 한국자동차공학회논문집
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• 제18권2호
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• pp.97-103
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• 2010

The four combustion stages in a diesel engine have close correlation among them. Especially, the ignition delay period has significant effect on the following combustion stage. And the period is also one of inevitable combustion processes in the diesel engine. For example, the diesel knocking is a well-known phenomenon due to the long ignition delay period. The interval of the ignition delay period is affected by the mixture formation process in the cylinder. However, in the case of the D.I. diesel engine, the available duration to make the mixture formation of air-fuel is very short. In addition, the means of the mixture formation mainly depends on the injection characteristics and properties of the fuel. It is difficult to make complete mixture. Therefore, an early stage of combustion is violent, which leads to the weakness of noise and vibration. In this study, using the visible engine, we measured the ignition delay period by photo sensor which detect occurrence of flame and presented the factors of the injection characteristics such as kinds of injection system, the injection pressure and the injection timing. The relation between the ignition delay period and cylinder pressure diagram which was concurrently obtained was also estimated.

• 한국실내디자인학회논문집
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• 제18권3호
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• pp.66-73
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• 2009

In the digital age, as it is ambiguous to distinguish between the original and a replica, the order of reproduction which is more realistic than the reality is becoming a new cultural order. Before the period when digital paradigm dominates, always the reality has been an object to be copied. But, today is an age of Simulacre where code of digital technology dominates. Such a phenomenon is shown in the construction space without exception Gilles Deleuze who was a representative philosopher of the post-structuralism depicted the concept of Simulacre as an instant 'event' passing by without change in an object or substance. As the result of analyzing what kinds of feature for the concept of event is expressed in the digital space, a diagram itself could be a design process, the digital space with correlation was able to be created through the change in the meaning according to the changing image and my body which was the leading part to form primary space. In such a meaning, this study pays attention to Deleuze's 'Event(Simulacre)' concept. At this transitional period when a new concept of digital space is about to take root, the modern philosophers' theories and the discussions about spatial relativity should be continually studied, along with the development of spacial theories for the modem construction.

• 전기학회논문지
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• 제61권9호
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• pp.1380-1386
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• 2012

It is important to consider supply voltage stability in case of design and construction of a substation at electric railway because a urban transit is operated by electricity and it is driven simultaneous in the same section. This paper study on variation of the dynamic characteristic of supply voltage according to the track environment and spatial distribution as driving of urban transits. Simulation tool, TOM(Train Operations Model) software is used to ensure stability of feeder system being used around the world. As results of simulation, voltage of the contact wire is in limits on driving operation diagram of urban transits. Also, it has confirmed that there is a correlation the phase current, depending on the speed of urban transit and track environment like vertical gradients and curve radius.