• 디지털콘텐츠학회 논문지
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• 제16권6호
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• pp.951-959
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• 2015

장면 텍스트 추출은 현대 스마트 시대에서 쏟아져 나오는 다양한 영상 기반 응용에 중요한 정보를 제공하기 때문에 중요하다. 기본적인 MSER(Maximally Stable Extremal Regions) 추출 후에 캐니 연산자를 이용하여 경계를 강화시키는 Edge-Enhanced MSER은 텍스트 추출 측면에서 뛰어난 성능을 보인다. 하지만 캐니 연산자의 임계값 설정에 따라 Edge-Enhanced MSER의 결과영상이 다르게 나타나므로 임계값 설정을 계산하는 방법이 필요하다. 본 논문에서는 캐니 연산자의 임계값을 설정하는 방법 중 히스토그램의 중앙값을 이용하여 경계를 추출하고 이를 Edge-Enhanced MSER에 적용한 AEMSER(Adaptive Edge-enhanced MSER)을 제안한다. 이 방법은 명확한 경계에 대해서만 영역을 추출하기 때문에 기존의 방법보다 더 좋은 결과영상을 얻을 수 있다.

• The Journal of Korean Physical Therapy
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• 제26권6호
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• pp.442-448
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• 2014

Purpose: The objective of this study is to evaluate the effect of neuro-feedback training and transcutaneous electrical nerve stimulation (TENS) on stress, quantitative sensory threshold and pain in patients suffering from tension type headache. Methods: 22 participants who passed the preliminary evaluation were enrolled in the study and 11 participants were randomly assigned to each group. The control group (n=11) was subject to the TENS treatment of which was composed of a 20-minute session for 5 times a week during 4 weeks, and the experimental group (n=11) was subject to both neuro feedback training and TENS treatment for 10 minutes a day and 5 days a week during 4 weeks. The Perceived Stress Scale (PSS) was used to measure a level of stress and the quantitative sensory testing (QST) was used for the measurement of cold pain threshold (CPT) and heat pain threshold (HPT); A degree of pain was evaluated through the headache impact test-6 (HIT-6). Results: In comparision of all dependent variables between the control and subject groups, there were significant differences in stress, quantitative sensory threshold and pain after the treatment (p<0.05), and the experimental group showed significant differences in stress, CPT, HPT and pain (p<0.05) and the control group showed only a significant difference in HPT (p<0.05). Conclusion: Findings of this study demonstrate that the concomitant administration of the TENS treatment and neuro feedback training is effective on alleviation of stress, quantitative sensory threshold and pain in patients with tension type headache.

• 한국지능시스템학회논문지
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• 제20권3호
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• pp.368-374
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• 2010

영상 분할 (Image Segmentation)은 패턴 인식, 환경 인식, 문서 분석을 위한 영상 처리 과정에서 가장 기본적인 단계이다. 영상 분할 방법들 중 Otsu의 영상의 정규화된 히스토그램의 분포 정보를 이용하여 클래스 간의 분산을 최대화 시키는 임계치값을 결정하는 자동 임계치값 선정방법이 가장 잘 알려진 방법이다. Otsu의 방법은 영상의 전 영역에 대한 히스토그램을 분석함으로써 영상의 부분적인 특성을 반영하여 임계치값을 결정하기는 어렵다. 본 논문에서는 이 어려움 해소하기 위하여 Context Fuzzy c-Means 알고리즘을 이용하여 영상을 여러 개의 부분 영역으로 나누고, 정의된 부 영역에 영상 분할 기법을 적용함으로써 부 영역들에 적합한 여러 개의 임계치값을 계산함으로써 영상 분할 성능을 개선하고자 하였다.

• 핵의학기술
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• 제20권1호
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• pp.52-58
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• 2016

최근 다양한 학회에서 PET 정보로부터 기인하는 SUVmax, MTV, TLG 등으로 환자의 생존율을 분석하는 후향적 연구가 활발히 진행 중이다. 그러나 종양의 체적을 정확하게 측정하기 어렵고 명확한 방법이 없으며 술자 간 차이가 발생 할 수 있다. 따라서 본 연구에서는 종양의 특성에 따른 체적 측정 방법을 비교 평가하였다. NEMA IEC Body Phantom에 18F-saline을 채우고 구형($0.5cm^3$ 에서 $26.5cm^3$)과 불균형($20cm^3$ 에서 $200cm^3$)의 체적을 phantom 안에 삽입하여 Biograph truepoint 40 (Siemens medical system, Germany)로 촬영하였다. 체적과 배후방사능과의 ratio를 3.0, 5.0, 8.0, 18, 40으로 나누어 촬영하였다. 임상환자는 소화기계 암의 병기 설정 환자로 2010년도부터 2014년도 까지 무작위로 120명을 선택하였고 측정방법은 40% threshold, 50% threshold 그리고 MIMsoftware의 gradient segmentation기법인 PET EDGE를 사용하였으며 5년 이상 2명의 방사선사와 1명의 전공의가 3번 반복 측정 하였다. 관찰자간일치도를 분석하였고 조영증강 CT 체적과 측정 체적과의 일치 상관관계 계수를 분석하였다. Phantom test의 결과는 40% threshold 방법이 가장 우수하였다(r = 0.992, 0.997). 임상 환자 결과에서는 관찰자간일치도는 PET EDGE가 0.999 (CI: 0.998-0.999)로 높았고 측정 방법간의 통계적인 유의한 차이는 보이지 않았다(P = 0.620). CT체적과 PET 체적 간의 상관관계에선 40% 방법이 가장 우수하였다(r = 0.953). 그리고 종양과 배후방사능의 비가 증가할수록 측정 방법 간의 영향이 감소하였다. 임상 환자에서의 종양의 체적 측정 방법은 50% threshold방법이 가장 유용하고 종양의 특성에 대한 영향이 가장 적었다. 종양과 배후방사능의 비가 높을수록 측정 방법 간의 영향이 감소하기 때문에 PET/CT 검사에서 환자의 배후방사능을 줄이는 연구와 노력이 필요하다고 생각된다.

• Communications for Statistical Applications and Methods
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• 제8권2호
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• pp.573-579
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• 2001

Wavelet thresholding is a method for he reduction of noise in image. Wavelet coefficients of image are correlated in local characterization. Thee correlations also appear in he original pixel representation of the image, and they do not follow from the characterizations of the wavelet transform. In this paper, we compare noise-free distributions of Bayes approach to improve the classical threshold algorithm.

• 융합신호처리학회 학술대회논문집
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• 한국신호처리시스템학회 2001년도 하계 학술대회 논문집(KISPS SUMMER CONFERENCE 2001
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• pp.77-80
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• 2001

This paper presents a new threshold-based denoising method by using undecimated discrete wavelet transform (UDWT). It proved excellency of the UDWT compared with orthogonal wavelet transform (OWT), spatia1ly selective noise filtration (SSNF) and NSSNF added new parameter. Methods using the spatial correlation are effectual at edge detection and image enhancement, whereas algorithm is complex and needs more computation However, UDWT is effective at denoising and needs less computation and simple algorithm.

• Safety and Health at Work
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• 제8권2호
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• pp.206-211
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• 2017

Background: Self-reported low back pain (LBP) has been evaluated in relation to material handling lifting tasks, but little research has focused on relating quantifiable stressors to LBP at the individual level. The National Institute for Occupational Safety and Health (NIOSH) Composite Lifting Index (CLI) has been used to quantify stressors for lifting tasks. A chemical exposure can be readily used as an exposure metric or stressor for chemical risk assessment (RA). Defining and quantifying lifting nonchemical stressors and related adverse responses is more difficult. Stressor-response models appropriate for CLI and LBP associations do not easily fit in common chemical RA modeling techniques (e.g., Benchmark Dose methods), so different approaches were tried. Methods: This work used prospective data from 138 manufacturing workers to consider the linkage of the occupational stressor of material lifting to LBP. The final model used a Bayesian random threshold approach to estimate the probability of an increase in LBP as a threshold step function. Results: Using maximal and mean CLI values, a significant increase in the probability of LBP for values above 1.5 was found. Conclusion: A risk of LBP associated with CLI values > 1.5 existed in this worker population. The relevance for other populations requires further study.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권10호
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• pp.3851-3866
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• 2015

The dynamic nature of opportunistic networks results in long delays, low rates of success for deliveries, etc. As such user experience is limited, and the further development of opportunistic networks is constrained. This paper proposes a prediction-based routing method for opportunistic networks (PB-OppNet). Firstly, using an ARIMA model, PB-OppNet describes the historical contact information between a node pair as a time series to predict the average encounter time interval of the node pair. Secondly, using an optimal stopping rule, PB-OppNet obtains a threshold for encounter time intervals as forwarding utility. Based on this threshold, a node can easily make decisions of stopping observing, or delivering messages when potential forwarding nodes enter its communication range. It can also report different encounter time intervals to the destination node. With the threshold, PB-OppNet can achieve a better compromise of forwarding utility and waiting delay, so that delivery delay is minimized. The simulation experiment result presented here shows that PB-OppNet is better than existing methods in prediction accuracy for links, delivery delays, delivery success rates, etc.

• 한국초전도ㆍ저온공학회논문지
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• 제11권3호
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• pp.20-25
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• 2009

The quench detection system of the KSTAR (Korea Superconducting Tokamak Advanced Research) primarily uses the resistive voltage measurement due to a quench. This method is to detect the resistive voltage generated by a quench, which is continuously maintained above the preset voltage threshold for a given holding time. As the KSTAR PF (Poloidal Field) coils are operated in the pulse current mode, the large inductive voltages are generated. Therefore the voltage threshold and the quench holding time should be determined by considering both the inductive voltages measured during the operation, and the maximum conductor temperature rise through the quench analysis. In this paper, the compensation methods for minimizing the inductive voltages are presented for the KSTAR PF coils. The quench hot spot analysis of the PF coils was carried out by the analytical and numerical methods for determining the proper values of the quench voltage threshold and the allowable quench protection delay time.

• 대한물리치료과학회지
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• 제3권3호
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• pp.25-34
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• 1996

The purpose of this experimental study was conducted to examine the most effective modality between two methods of cold application(ice pack and cold spray), the most effective length of time for the application and the continuing effect after each type of cold application. Sixty students were assigned randomly to each of two cold application methods; (a) ice pack, (2) cold spray. Each methods was applied to the posterior surface of right forearm with subject in the sitting position. Skin temperature and the electrical stimulation induced pain threshold were measured before each application and every five degree ($^{\circ}C$) decline point after ice pack application. They were also measured point of minimum skin temperature after cold spray application. The results of this study are as follows; 1. Skin temperatures according to the cold spray application decreased to a range of $4.2^{\circ}C{\sim}9.2^{\circ}C$(male, p<0.001), $3.6^{\circ}C{\sim}7.6^{\circ}C$(female, p<0.001). 2. Pain threshold according to the cold spray application increased to a range of $0.6mA{\sim}1.9mA$(male, p<0.01), $1.2mA{\sim}3.86mA$(female, p>0.05).