• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.12
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• pp.2924-2932
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• 2015

Image binarization is a process to divide the image into objects and backgrounds, widely applied to the fields of image analysis and its recognition. In the existing method of binarization, there is some uncertainty when there is insufficient brightness gap between objects and backgrounds in setting threshold. The method of fuzzy binarization has improved the features of objects efficiently. However, since this method sets ${\alpha}$-cut value statically, there remain some problems that important features of objects can be lost during binarization. Therefore, in this paper, we propose a binarization method which does not set ${\alpha}$-cut value statically. The proposed method uses fuzzy membership functions calculated by thresholds of mean, iterative, and Otsu binarization. Experiment results show the proposed method binaries various images with less loss than the existing methods.

• Spatial Information Research
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• v.19 no.5
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• pp.1-11
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• 2011

This study mainly focused on the method of accurately extracting damage information in the im agery change detection process using the constructed high resolution aerial im agery. Bongwha-gun in Gyungsangbuk-do which had been severely damaged from a localized torrential downpour at the end of July, 2008 was selected as study area. This study utilized aerial im agery having photographing scale of 30cm gray image of pre-disaster and 40cm color image of post-disaster. In order to correct errors from the differences of the image resolution of pre-/post-disaster and time series, the prelim inary phase of image processing techniques such as normalizing, contrast enhancement and equalizing were applied to reduce errors. The extent of the damage was calculated using one to one comparison of the intensity of each pixel of pre-/post-disaster im aged. In this step, threshold values which facilitate to extract the extent that damage investigator wants were applied by setting difference values of the intensity of pixel of pre-/post-disaster. The accuracy of optimal image processing and the result of threshold values were verified using the error matrix. The results of the study enabled the early exaction of the extents of the damages using the aerial imagery with identical characteristics. It was also possible to apply to various damage items for imagery change detection in case of utilizing multi-band im agery. Furthermore, more quantitative estimation of the dam ages would be possible with the use of numerous GIS layers such as land cover and cadastral maps.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10c
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• pp.223-225
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• 2004

Ad-Hoc 네트워크에서 기존의 On-Demand 방식의 라우팅 프로토콜은 네트워크에서 현재 사용 중인 경로가 혼잡하어라도 네트워크 토폴로지가 변하기 이전에는 새로운 경로를 찾지 못하므로 노드의 이동성이 낮은 환경에서는 트래픽이 특정노드로 집중되는 문제가 발생한다 또한 노드들의 이동성이 낮아 네트워크가 안정된 상태인 경우 특정 노드의 트래픽이 고려되지 않은 상태에서 최단 경로만을 선택하여 데이터를 전송하기 때문에 특정노드에 트래픽이 집중되어 전송지연 및 과도한 에너지 소비를 발생시킨다는 문제점을 갖는다. 이런 특정 노드의 과도한 에너지 소비를 차단하여 전체 네트워크의 수명을 연장시키기 위한 효과적인 방법을 찾기 위한 노력이 진행되고 있다. 본 논문에서는 이러한 문제를 해결하기 위해 기존의 DSR에 에너지 소비율을 기반으로 경로설정 및 대체경로 설정기능을 추가한 ECLB(Energy Consumption based Load Balancing Method)를 제안한다. ECLB는 현재의 단위시간당 처리되는 패킷수와 과거의 평균 패킷처리율을 바탕으로 에너지 임계치(energy threshold)를 설정하고 이를 바탕으로 최적의 경로를 설정한다. 또한 계속적으로 동일 전송 경로를 사용함으로 인한 특정노드에 대한 에너지 소모의 심화와 전송지연을 최소화하기 위해 과중한 트래픽 상태를 분산시킬 수 있는 대체경로를 이용하여 데이터 집중에 따른 손실을 최소화시킨다.

• Journal of the Korean Society for information Management
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• v.30 no.3
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• pp.273-296
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• 2013

The purpose of this study is to examine the data coverage and citation threshold for analyzing SPLC(Search Path Link Count) as a main path of a historiograph of a certain topic in order to provide 'core' papers of global research trends to a researcher affiliated with a local R&D institution. 5 datasets were constructed by retrieving and collecting 2,318 articles on RGB LED on Web of Science published from 1990-2013 and 20,109 articles which cited these original 2,318. The SPLC analysis was performed on each dataset by increasing the threshold of citation counts, and the changes and resilience of the 28 extraced networks were compared. The results of user feedback on 198 unique core papers from 28 SPLC networks received from LED researchers affiliated with a Korean government-sponsored research institution were also analyzed. As a result, it is found that the nodes in each SPLC network in each dataset were differentiated by the citation counts, while the changes in the structure of SPLC networks were slight after the networks' citation counts were set at 40. Additionally, the user feedback showed that personalized research interest generally matched to the global research trends identified by the SPLC analysis.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11c
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• pp.1617-1620
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• 2003

본 논문은 사용자 질의가 가지는 특정 클래스로부터 개념적으로 서로 연관있는 컴포넌트를 검색하기 위하여 퍼지 시소러스를 통한 질의 평가 방법을 이용하였다. 시소러스에 의한 사용자 질의 확장과정은 용어 불일치 문제를 해결함으로써 검색에 대한 일정한 정확도를 보장하면서 재현율을 향상시킬 수 있게 한다. 필의 확장과정의 효율성을 평가하기 위하여 시뮬레이션을 통한 최적의 검색 효율을 나타내는 임계치를 설정하고 재현율과 정확도를 비교하였다.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.2
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• pp.231-236
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• 2011

The binarization algorithm frequently applies to one part of the preprocessing phase for a variety of image processing techniques such as image recognition and image analysis, etc. So it is important that binarization algorithm is determined by the selection of threshold value for binarization in image processing. The previous algorithms could get the proper threshold value in the case that shows all the difference of brightness between background and object, but if not, they could not get the proper threshold value. In this paper, we propose the efficient fuzzy binarization method which first, segments the brightness range of gray_scale images to 2 intervals to perform car license plate binarization and applies fuzzy member function to each intervals. The experiment for performance evaluation of the proposed binarization algorithm showed that the proposed algorithm generates the more effective threshold value than the previous algorithms in car license plate.

• The Transactions of the Korea Information Processing Society
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• v.4 no.10
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• pp.2605-2614
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• 1997

Recently, we are concerned with effective service according as the demand increase for high speed data service. We can use high speed transfer and multiple traffic service on the ATM networks, so we concentrate on preventive-control method rather than reactive-control one. But it is possible to have low QoS and traffic congestion due to unpredictable traffic and burst traffic. Specially, ATM Forum has discussed to standardization of traffic management of ABR(Available Bit Rate) service. Because ABR traffic controls the flow of traffic using the feedback information and the current status information of cell, it allocates bandwidth systematically and dynamically to the user. In this paper, we propose a new Rate-based flow control scheme which adapted double threshold buffer idea. The double threshold buffer controls the traffic control by establishing two threshold in buffer.

• Journal of Korea Multimedia Society
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• v.7 no.5
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• pp.744-754
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• 2004

In this paper, a polarity based blind watermarking method considering wavelet coefficients modification is proposed. In this proposed method, we use an asymmetric thresholds watermarking(ATW) in which detection threshold is higher than inserting threshold in order to enhance watermark detection ratio in attacked images. Also, in order to reduce errors in the detected value of watermarks according to small changes in the coefficient values when detecting watermarks, it set the range for movement variation of the coefficients and lowered the sensitivity of variation by ignoring the variations that fall into this range. For this purpose, the polarity preservation threshold $\beta$ was set and a watermark was detected based on the polarity only for the difference that was larger than $\beta$. The experimental results show that the proposed method has good quality and is robust to various attacks such as the JPEG lossy compression, noise addition, cropping, blurring, etc.

• Progress in Medical Physics
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• v.22 no.1
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• pp.42-51
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• 2011

Nuclear medicine images (SPECT, PET) were widely used tool for assessment of myocardial viability and perfusion. However it had difficult to define accurate myocardial infarct region. The purpose of this study was to investigate methodological approach for automatic measurement of rat myocardial infarct size using polar map with adaptive threshold. Rat myocardial infarction model was induced by ligation of the left circumflex artery. PET images were obtained after intravenous injection of 37 MBq $^{18}F$-FDG. After 60 min uptake, each animal was scanned for 20 min with ECG gating. PET data were reconstructed using ordered subset expectation maximization (OSEM) 2D. To automatically make the myocardial contour and generate polar map, we used QGS software (Cedars-Sinai Medical Center). The reference infarct size was defined by infarction area percentage of the total left myocardium using TTC staining. We used three threshold methods (predefined threshold, Otsu and Multi Gaussian mixture model; MGMM). Predefined threshold method was commonly used in other studies. We applied threshold value form 10% to 90% in step of 10%. Otsu algorithm calculated threshold with the maximum between class variance. MGMM method estimated the distribution of image intensity using multiple Gaussian mixture models (MGMM2, ${\cdots}$ MGMM5) and calculated adaptive threshold. The infarct size in polar map was calculated as the percentage of lower threshold area in polar map from the total polar map area. The measured infarct size using different threshold methods was evaluated by comparison with reference infarct size. The mean difference between with polar map defect size by predefined thresholds (20%, 30%, and 40%) and reference infarct size were $7.04{\pm}3.44%$, $3.87{\pm}2.09%$ and $2.15{\pm}2.07%$, respectively. Otsu verse reference infarct size was $3.56{\pm}4.16%$. MGMM methods verse reference infarct size was $2.29{\pm}1.94%$. The predefined threshold (30%) showed the smallest mean difference with reference infarct size. However, MGMM was more accurate than predefined threshold in under 10% reference infarct size case (MGMM: 0.006%, predefined threshold: 0.59%). In this study, we was to evaluate myocardial infarct size in polar map using multiple Gaussian mixture model. MGMM method was provide adaptive threshold in each subject and will be a useful for automatic measurement of infarct size.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.55-60
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• 2016

In the traditional wireless LAN model, scan procedure to search a new AP starts when the predefined number of Rx failure of beacon frames are occurred. In this case, lots of data packet loss occur during MN's handover because loss of the relatively longer data packet starts before the small-sized beacon loss. Newly developed scanning mechanism in this paper has the beacon counter that increases when the Rx power level of beacon frame is less than the threshold and the previous rx power level. New scan procedure starts when the counter exceeds the predefined number. Beacon Rx power threshold is verified and performance of the new WLAN model is evaluated under UDP and TCP traffic environment.