• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.507-509
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• 2012

많은 사용자가 직접 글을 작성하고 데이터를 업로드 하는 SNS 서비스의 데이터 분류 및 분석에서 빅 데이터 활용방안이 다양하게 논의되고 있다. 특히 기존에 활용하던 텍스트 기반의 분류에서 이미지, 동영상에 대한 분류가 다양하게 시도되고 있다. 본 논문에서는 위키피디아를 이용한 이미지 태그의 의미정보를 바탕으로 플리커에서 샘플 이미지를 추출하고 이를 활용하여 'bag of visual word' 기법으로 사용자가 업로드한 이미지를 자동 분류하는 방법을 소개한다.

• Journal of Digital Convergence
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• v.13 no.12
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• pp.203-208
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• 2015

Image degradation will occur depending on hardware characteristics according to the lapse of time between beam projectors when multivision system is installed in the Theme park/Exhibition/Science Museum. In this paper, we have researched the 10-bit High-depth and high-resolution $360^{\circ}$ projection image analysis technique to solve the problems of quality and the maintenance of the theater. The goal is to minimize the economic losses and the development of special theater calibration system that can efficiently support a quality of an image. We proposed the method of image analysis technology, and explained the detailed functions and evaluation methods for image analysis technique. Evaluation method included the performance items, and proposed reasonable value to the experimental method and the goal value.

• Journal of the Korean Society for Library and Information Science
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• v.44 no.1
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• pp.117-135
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• 2010

We designed a structured folksonomy system in which queries can be expanded through tag control; equivalent, synonym or related tags are bound together, in order to improve the retrieval efficiency (recall and precision) of image data. Then, we evaluated the proposed system by comparing it to a tag-based system without tag control in terms of recall, precision, and user satisfaction. Furthermore, we also investigated which query expansion method is the most efficient in terms of retrieval performance. The experimental results showed that the recall, precision, and user satisfaction rates of the proposed system are statistically higher than the rates of the tag-based system, respectively. On the other hand, there are significant differences among the precision rates of query expansion methods but there are no significant differences among their recall rates. The proposed system can be utilized as a guide on how to effectively index and retrieve the digital content of digital library systems in the Library 2.0 era.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.10
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• pp.35-39
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• 2007

Home appliances, like air-conditionals, washers, refrigerators, etc., can cause voltage fluctuations and light flicker. A standardized flicker test has been established in Europe(IEC 61000-3-3, IEC 61000-3-11). The supply impedance of power supply system varies from plate to place, and for the flicker test in KOREA, the appliance manufacturers do need standardized impedance like the one indicated in IEC 61000-3-3 for 230[V]/50[Hz]. Without it, the same appliance will have different flicker level at different places. For appliance manufacturers, the flicker limit should be related to the reference impedance. However, the European flicker test is designed for 230[V]/50[Hz] power and needs to be modified for a 1P2W(220[V]/60[Hz]) supply system in KOREA. In this paper, the reference impedance for KOREA(220[V]/60[Hz]) systems is proposed. The measured result provided in this paper was served as a proposal for establishing KOREA reference impedance for 220[V]/60[Hz] and has been published in IEC 60725.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.5
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• pp.118-125
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• 2004

The use of electric arc furnace has been increasing as the steel consumption is increasing and the operation technique of electric arc furnace are developing. But as the use of electric arc furnace is increased, the furnace have produced the adverse effects of power quality: voltage and current harmonics, voltage and current imbalances, low power factor, and voltage flicker. One of the power quality problems, the harmonic have the characteristics of the time-varying and non-linear. This paper analyzed the harmonics for the various operation conditions of electric arc furnace. The power system model with electric arc furnace have been made, and the harmonic's effects on the power system has been analyzed according to the various operating conditions, first melting, second melting, so on. Also, the filter reducing the harmonic components have been designed and its effects on the power system have been examined.

• KIPS Transactions on Software and Data Engineering
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• v.3 no.12
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• pp.547-552
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• 2014

As social multimedia sites are getting popular such as Flickr and Facebook, the amount of image information has been increasing very fast. So there have been many studies for accurate social image retrieval. Some of them were web image classification using semantic relations of image tags and BoVW(Bag of Visual Words). In this paper, we propose a method to detect salient region in images using GBVS(Graph Based Visual Saliency) model which can eliminate less important region like a background. First, We construct BoVW based on SIFT algorithm from the database of the preliminary retrieved images with semantically related tags. Second, detect salient region in test images using GBVS model. The result of image classification showed higher accuracy than the previous research. Therefore we expect that our method can classify a variety of images more accurately.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.6
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• pp.147-153
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• 2010

When small scale wind and solar power generation systems are connected to conventional power distribution system. It is worried that it can affect the quality of electricity such as voltage variation, power factor, frequency, harmonics and flicker. Therefore, in this research, in order to investigate the effects of wind power generation equipments(AC link method) on electrical power quality, when they are connected to distribution system. Power quality analyzer was installed respectively at the front side of power conversion system of conventional wind generation system and secondary side of consumer's power supply at distribution line. Measurements on power quality were performed and the effects of the wind generation system on distribution system were analyzed when it was and was not operated. The results show that 0.34[%] increase on voltage variation, 0.145 increase on current crest factor and 0.6[$^{\circ}$] deviation on phase difference when the power generation system was operated.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.209-216
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• 2012

The purpose of this study is to find the UCC (User Created Contents) communication structure in the perspective of smart-phone technologies or SNS (Social Network Service). In developing the research model, we have focused on selecting the success factors appropriate for the UCC through reviewing past researches and on developing more accurate success measures. The model consists of relation each service (Facebook linked in Flickr and so on), relation of trust, transfer to Social Capital and so on . The result shows thar process of trust based in UCC is the most important determinants of structure and organization network. And collaboration relationship is the most important of SNS used in SSO and Open-API technologies. The practice characteristic of UCC has direct and indirect effect on SNS of improving social trust.

• Convergence Security Journal
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• v.14 no.7
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• pp.29-36
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• 2014

In this study, we design and develop a VLC test-bed system which has been recently issued and focused as good convergence technology in the world. We classify the developed system into transmission part including analog LED driver module, digital signal modulation module, and receiver part with light sensing module and signal demodulation module. Then we introduce important characteristics and components. We analyze some factors for each module. To validate the communication of the designed VLC system, we develop a VLC sender-receiver simulator which can control the dimming factor and flicker-free effect. From the developed system, we observed about 12Mbps of data transmission rate with 0.5m~1m of distance, without packet loss. We verified the real-time communication with multimedia streaming which can be considered as very high date rate. The developed system and technology will be useful for some converged data services like indoor positing, home appliances, and indoor parking system.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.2 s.302
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• pp.9-18
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• 2005

Flicker is the 'variation in brightness or he perceived won stimulation by intermittent or temporally non uniform light'. This phenomenon is blown as the cause of eye strain and headaches. Many researchers are dedicated to reducing this phenomenon. The flicker phenomenon also exists in PDP as some other display types, and is a critical problem in 50 Hz PDP. However, it is difficult to define flicker by more than one subjective judgment. So, an objective measurement of flicker is necessary and convenient for research on displays. In this paper, a computational prediction model is proposed which is used to predict luminance flicker (not chromatic flicker) by giving a quantitative output that describes the probability of occurrence of flicker. Through this work, we expected to provide a practical tool for flicker-free design in PDP.