• Title/Summary/Keyword: Visual threshold

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Cloud Detection Using HIMAWARI-8/AHI Based Reflectance Spectral Library Over Ocean (Himawari-8/AHI 기반 반사도 분광 라이브러리를 이용한 해양 구름 탐지)

  • Kwon, Chaeyoung;Seo, Minji;Han, Kyung-Soo
    • Korean Journal of Remote Sensing
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    • v.33 no.5_1
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    • pp.599-605
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    • 2017
  • Accurate cloud discrimination in satellite images strongly affects accuracy of remotely sensed parameter produced using it. Especially, cloud contaminated pixel over ocean is one of the major error factors such as Sea Surface Temperature (SST), ocean color, and chlorophyll-a retrievals,so accurate cloud detection is essential process and it can lead to understand ocean circulation. However, static threshold method using real-time algorithm such as Moderate Resolution Imaging Spectroradiometer (MODIS), Advanced Himawari Imager (AHI) can't fully explained reflectance variability over ocean as a function of relative positions between the sun - sea surface - satellite. In this paper, we assembled a reflectance spectral library as a function of Solar Zenith Angle (SZA) and Viewing Zenith Angle (VZA) from ocean surface reflectance with clear sky condition of Advanced Himawari Imager (AHI) identified by NOAA's cloud products and spectral library is used for applying the Dynamic Time Warping (DTW) to detect cloud pixels. We compared qualitatively between AHI cloud property and our results and it showed that AHI cloud property had general tendency toward overestimation and wrongly detected clear as unknown at high SZA. We validated by visual inspection with coincident imagery and it is generally appropriate.

The Efficacy of Repeated Radiofrequency Medial Branch Neurotomy for Lumbar Facet Syndrome

  • Son, Jung-Hee;Kim, Sang-Dae;Kim, Se-Hoon;Lim, Dong-Jun;Park, Jung-Yul
    • Journal of Korean Neurosurgical Society
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    • v.48 no.3
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    • pp.240-243
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    • 2010
  • Objective : Radiofrequency (RF) medial branch neurotomy is an effective management of lumbar facet syndrome. However, pain may recur after period of time. When pain recurs, it can be repeated, but the successful outcome and duration of relief from repeated procedures are not clearly known. The objective of this study was to determine the success rate and duration of pain relief from repeated radiofrequency medial branch neurotomy for lumbar facet syndrome. Methods : A retrospective review of medical records was done on 60 consecutive patients, from March of 2006 to February of 2009, who had an initial successful RF neurotomy but subsequently underwent repeated procedures due to recurrence of pain. All procedures were done in carefully selected patients after at least two responsive medial branch nerve blocks. C-arm fluoroscopic guide, impedance, sensory and motor threshold monitoring tools were used for the precise placement of electrodes. Responses of repeated procedures were compared with initial radiofrequency neurotomy for success rates and duration of pain relief. Results : There were 48 females and 12 males. Mean age was 52.4 years (range, 26-83). RF medial branch neurotomy was done on one side in 38 and both sides in 22 patients, each covering at least three segments. Average visual analog scale at last procedure was 6.8. Twelve patients had previous lumbar operations, including 4 patients with instrumentations. Fifty-five patients had two procedures and five patients had three procedures. Mean duration of successful pain relief (> 50% of previous pain for at least 3 months period) after initial radiofrequency neurotomy was 10.9 months (range, 3-28) in 51 (85%) patients. From repeated procedures, successful pain relief was seen in 50 (91%) patients with average duration of 10.2 months (range, 3-24). Five patients had third procedure, which was successful in 4 (80%) patients with mean duration of 9.8 months (range, 5-16). This was not statistically different from initial results. There were no permanent neurological complications from the procedures. Conclusion : Results of this study indicate that the frequency of success and durations of relief from repeated RF medial branch neurotomy for lumbar facet syndrome are similar to initial results that provided relatively prolonged period of pain relief without major side effects Each procedure seems to provide successful pain relief for about 10 months in more than 85% of carefully selected patients when properly done.

Design of Vision Based Punching Machine having Serial Communication

  • Lee, Young-Choon;Lee, Seong-Cheol;Kim, Seong-Min
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.2430-2434
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    • 2005
  • Automatic FPC punching instrument for the improvement of working condition and cost saving is introduced in this paper. FPC(flexible printed circuit) is used to detect the contact position of K/B and button like a cellular phone. Depending on the quality of the printed ink and position of reference punching point to the FPC, the resistance and current are varied to the malfunctioning values. The size of reference punching point is 2mm and the above. Because the punching operation is done manually, the accuracy of the punching degree is varied with operator's condition. Recently, The punching accuracy has deteriorated severely to the 2mm punching reference hall so that assembly of the K/B has hardly done. To improve this manual punching operation to the FPC, automatic FPC punching system is introduced. Precise mechanical parts like a 5-step stepping motor and ball screw mechanism are designed and tested and low cost PC camera is used for the sake of cost down instead of using high quality vision systems for the FA. 3D Mechanical design tool(Pro/E) is used to manage the exact tolerance circumstances and avoid design failures. Simulation is performed to make the complete vision based punching machine before assembly, and this procedure led to the manufacturing cost saving. As the image processing algorithms, dilation, erosion, and threshold calculation is applied to obtain an exact center position from the FPC print marks. These image processing algorithms made the original images having various noises have clean binary pixels which is easy to calculate the center position of print marks. Moment and Least square method are used to calculate the center position of objects. In this development circumstance, Moment method was superior to the Least square one at the calculation of speed and against noise. Main control panel is programmed by Visual C++ and graphical Active X for the whole management of vision based automatic punching machine. Operating modes like manual, calibration, and automatic mode are added to the main control panel for the compensation of bad FPC print conditions and mechanical tolerance occurring in the case of punch and die reassembly. Test algorithms and programs showed good results to the designed automatic punching system and led to the increase of productivity and huge cost down to law material like FPC by avoiding bad quality.

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Effects of Myofascial Release on Nerve Conduction Studies and Pain Scale in Middle-Aged Women (중년여성에서 근막이완요법이 신경전도와 통증에 미치는 영향)

  • Yon, Jung-Min;Lee, Hyun-Kyung;Lee, Og-Kyoung
    • Journal of Digital Convergence
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    • v.12 no.6
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    • pp.425-432
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    • 2014
  • The purpose of this study was to examine the effect of myofascical release (MR) on the degree of pain and nerve conduction velocity (NCV) in middle-aged women. Participants were 28 middle-aged women and MR carried out three times (1, 3, 5 day) at intervals of two times. We did survey about changes of pain before the MR and how they changed after the MR. Also measured pressure pain threshold (PPT) and visual analogue scale (VAS) by using the algometer at trapezius muscle. In median nerve, we did motor nerve conduction velocity (MNCV) test and sensory nerve conduction velocity (SNCV) test for measuring incubation period, amplitude and nerve conduction. The most painful time was 18~21 and the most painful part was shoulder. The pain scale, PPT and VAS after the MR had significantly decreased than before the MR. The latency was significantly decreased and the amplitude was significantly increased in the MNCV and the latency was significantly decreased in the SNCV after the MR. Also it was effective in ameliorating pain scale and latency of NCV. Consequently, the MR can be effective in prevent pain scale caused by fatigue in middle-aged women as replacement therapy.

A Literatural Investigation of Diagnosis Methods and Evaluation Outcomes for the Clinical Trials on Temporomandibular Disorders (측두하악장애 임상연구에 사용된 진단 및 평가기준에 대한 문헌적 고찰)

  • Moon, Byung-Heon;Choi, Young-Jun;Yoo, Su-Bin;Ju, Yeung-Guk;Song, Seong-Bae;Song, Gwang-Chan;Seo, Ji-Yeon;Choi, Hee-Seung
    • Journal of Korean Medicine Rehabilitation
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    • v.26 no.4
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    • pp.45-55
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    • 2016
  • Objectives The aim of this review is to provide fundamental data for temporomandibular disorders diagnosis and evaluation criteria which can be used in clinical trial. Methods We investigated the clinical studies on temporomandibular disorders via PubMed. Also, we searched domestic articles through "OASIS", "NDSL", "KISS", "Korean Traditional Knowledge Portal (KTKP)". The articles we focused on were the recent decade from 2007 to 2016. A total of 139 studies were analyzed: 42 domestic articles and 97 overseas articles. This study focuses on the diagnosis and evaluation criteria on temporomandibular disorders. Results 1) In diagnosis criteria, Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) was used 14 times in domestic articles and 63 times in overseas articles. Clinical symptoms were used 13 times in domestic articles, 17 times in overseas articles. 2) In evaluation criteria, Visual Analog Scale (VAS) was used as a pain scale 12 times in domestic articles, 63 times in overseas articles. Pressure Pain Threshold (PPT) was used 16 times in overseas articles. Whereas, no clinical trials used PPT in domestic articles. In psychological scale, Symptom Checklist-90-Revised (SCL-90-R) was used 6 times. However, SCL-90-R was used 2 times in domestic articles. ROM(Maximum Mouth Opening (MMO), Maximum Comfortable Opening (MCO) were used 24 times in overseas. In domestic articles, MMO was counted 12 times, while MCO was counted 5 times. Conclusions This research reviewed the tendency of using diagnosis methods and evaluating outcomes of the clinical on TMD. It is expected that this investigation would develop further treatment for TMD in the Korean Medicine.

Automatic Detection of Malfunctioning Photovoltaic Modules Using Unmanned Aerial Vehicle Thermal Infrared Images

  • Kim, Dusik;Youn, Junhee;Kim, Changyoon
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.34 no.6
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    • pp.619-627
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    • 2016
  • Cells of a PV (photovoltaic) module can suffer defects due to various causes resulting in a loss of power output. As a malfunctioning cell has a higher temperature than adjacent normal cells, it can be easily detected with a thermal infrared sensor. A conventional method of PV cell inspection is to use a hand-held infrared sensor for visual inspection. The main disadvantages of this method, when applied to a large-scale PV power plant, are that it is time-consuming and costly. This paper presents an algorithm for automatically detecting defective PV panels using images captured with a thermal imaging camera from an UAV (unmanned aerial vehicle). The proposed algorithm uses statistical analysis of thermal intensity (surface temperature) characteristics of each PV module to verify the mean intensity and standard deviation of each panel as parameters for fault diagnosis. One of the characteristics of thermal infrared imaging is that the larger the distance between sensor and target, the lower the measured temperature of the object. Consequently, a global detection rule using the mean intensity of all panels in the fault detection algorithm is not applicable. Therefore, a local detection rule was applied to automatically detect defective panels using the mean intensity and standard deviation range of each panel by array. The performance of the proposed algorithm was tested on three sample images; this verified a detection accuracy of defective panels of 97% or higher. In addition, as the proposed algorithm can adjust the range of threshold values for judging malfunction at the array level, the local detection rule is considered better suited for highly sensitive fault detection compared to a global detection rule. In this study, we used a panel area extraction method that we previously developed; fault detection accuracy would be improved if panel area extraction from images was more precise. Furthermore, the proposed algorithm contributes to the development of a maintenance and repair system for large-scale PV power plants, in combination with a geo-referencing algorithm for accurate determination of panel locations using sensor-based orientation parameters and photogrammetry from ground control points.

Sleep/Wake Dynamic Classifier based on Wearable Accelerometer Device Measurement (웨어러블 가속도 기기 측정에 의한 수면/비수면 동적 분류)

  • Park, Jaihyun;Kim, Daehun;Ku, Bonhwa;Ko, Hanseok
    • Journal of the Institute of Electronics and Information Engineers
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    • v.52 no.6
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    • pp.126-134
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    • 2015
  • A sleep disorder is being recognized as one of the major health issues related to high levels of stress. At the same time, interests about quality of sleep are rapidly increasing. However, diagnosing sleep disorder is not a simple task because patients should undergo polysomnography test, which requires a long time and high cost. To solve this problem, an accelerometer embedded wrist-worn device is being considered as a simple and low cost solution. However, conventional methods determine a state of user to "sleep" or "wake" according to whether values of individual section's accelerometer data exceed a certain threshold or not. As a result, a high miss-classification rate is observed due to user's intermittent movements while sleeping and tiny movements while awake. In this paper, we propose a novel method that resolves the above problems by employing a dynamic classifier which evaluates a similarity between the neighboring data scores obtained from SVM classifier. A performance of the proposed method is evaluated using 50 data sets and its superiority is verified by achieving 88.9% accuracy, 88.9% sensitivity, and 88.5% specificity.

Chromatic adaptation model for the variations of the luminance of the same chromaticity illuminants (동일 색도 광원의 휘도 변화에 따른 색 순응 모델)

  • Kim Eun-Su;Jang Soo-Wook;Lee Sung-Hak;Sohng Kyu-lk
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.42 no.4 s.304
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    • pp.31-38
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    • 2005
  • In this paper, we propose the chromatic adaptation models (CAM) for the variations of the luminance levels. A chromatic adaptation model, CAM$\Delta$Y , is proposed according to the change of luminance level under the same illuminants. The proposed model is obtained by the transform the test colors of the high luminance into the corresponding colors of the low luminance. In the proposed model, the optimal coefficients are obtained from the corresponding colors data of the Breneman's experiments. In the experimental results, we confined that the chromaticity errors, $\Delta$u'v', between the predicted colors by the proposed model and the corresponding colors of the Breneman's experiments are 0.004 in u'v' chromaticity coordinates. The prediction performance of the proposed model is excellent because this error is the threshold value that two adjacent color patches can be distinguished. Additionally, we also propose equal-whiteness CCT curves (EWCs) by CAM$\Delta$Y according to the luminance levels of the surround viewing conditions. And the proposed EWCs can be used as the theoretical standard which determines the reference white of the color display devices.

Comparison between the Subjective Evaluation and the Objective Evaluation of the Effect of Pain Control in the Masticatory Muscle Pain

  • Kim, Dong-Keun;Ahn, Chi-Hyuk;Hwang, Mi-Jin;Lee, Yeon-Hee;Kang, Soo-Kyung;Auh, Q-Schick;Hong, Jung-Pyo;Chun, Yang-Hyun
    • Journal of Oral Medicine and Pain
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    • v.41 no.2
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    • pp.61-71
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    • 2016
  • Purpose: This study was designed to evaluate the comparison between the subjective and the objective evaluation of pain control effect in masticatory muscle pain depending on time and dose change. Methods: The patients were recruited to this study and diagnosed according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Experimental group were divided into three groups; saline injection group (n=10), morphine 1.5 mg injection group (n=10), and morphine 3.0 mg injection group (n=10). Evaluation list was the subjective pain evaluation (visual analogue scale, McGill pain questionnaire) and the objective pain evaluation (pressure pain threshold [PPT], pressure pain tolerance [PTO]). The subjective and the objective pain evaluation were performed at the times of just before injection, 10 minutes, 30 minutes, 1 hour, 24 hours, and 48 hours after injection. Then, data were statistically analyzed. Results: The results were as follows: 1) There is no statistically significant difference between the results of the subjective and the objective pain evaluation with regard to the short-term (within 1 hour) analgesic effect of morphine sulfate. 2) However, after 1 hour of injection, while the subjective pain evaluation score still decreased, the objective pain evaluation didn't show significant changes in PPT and PTO (1 hour, p<0.05; 24 hours, p<0.01; 48 hours, p<0.001). 3) In comparison to changes in the dose, the McGill pain questionnaire was the most statistically effective method among the subjective pain evaluations (1.5 mg, p<0.05; 3 mg, p<0.01). Conclusions: Therefore, it was revealed that the subjective pain evaluation was more effective to evaluate long-term pain control, and that the McGill pain questionnaire could be an effective way to evaluate pain control depending on dose changes. It requires further investigations with time and dose extension.

Electron emission stability from CNTs with various densities (탄소나노튜브 밀도의 변화에 따른 전자방출 안정성 연구)

  • Lim Sung Hoon;Yun Hyun Sik;Ryu Je Hwang;Moon Jong Hyun;Park Kyu Chang;Jang Jin;Moon Byeong Yeon
    • Journal of the Korean Vacuum Society
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    • v.14 no.4
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    • pp.258-262
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    • 2005
  • We report on the field emission properties from vertically aligned carbon nanotubes (CNTs) produced by a triode PECVD with a SiNx capping layer on metal catalyst. It is found that the CNTs density can be controlled by the capping layer thickness and decreases with increasing SiNx thickness. The CNT density of $\~$ 104/$cm^{2}$ exhibited highest electron emission characteristics, the threshold field of 1.2 V/$\mu$m and the current density of 0.17 mA/$cm^{2}$ at 3.6 V/$\mu$m. We have carried out investigation of electron emission stability under ambient gas of N2. The electron emission stability was improved with decreasing CNT density. Under $1\times$$10^{-5}$ Torr ambient pressure, the CNTs in 5 $\mu$m hole show electron emission current higher than $1\times$$10^{-4}$ A/cm2 and it's electron emission uniformity has $2\%$.