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Search Results: 1 - 10 of 77753 matches for " Yin-Yi Wu "
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Implementation of RANSAC Algorithm for Feature-Based Image Registration  [PDF]
Lan-Rong Dung, Chang-Min Huang, Yin-Yi Wu
Journal of Computer and Communications (JCC) , 2013, DOI: 10.4236/jcc.2013.16009

This paper describes the hardware implementation of the RANdom Sample Consensus (RANSAC) algorithm for featured-based image registration applications. The Multiple-Input Signature Register (MISR) and the index register are used to achieve the random sampling effect. The systolic array architecture is adopted to implement the forward elimination step in the Gaussian elimination. The computational complexity in the forward elimination is reduced by sharing the coefficient matrix. As a result, the area of the hardware cost is reduced by more than 50%. The proposed architecture is realized using Verilog and achieves real-time calculation on 30 fps 1024 * 1024 video stream on 100 MHz clock.

Implementation of Shock Filter for Digital X-Ray Image Processing  [PDF]
Lan-Rong Dung, Shang-Ting Sun, Yin-Yi Wu
Journal of Computer and Communications (JCC) , 2014, DOI: 10.4236/jcc.2014.213004

X-ray image might be corrupted by noise or blurring because of signal transmission or the bad X- ray lens. This paper presents a two-stage shock filter based on Partial Differential Equations (PDE) to restore noisy blurred X-ray image. Shock filters are popular morphological methods. They are used for noise removal, edge enhancement and image segmentation. Our experimental results show that the performances of shock filter are excellent in X-ray image. The peak signal-to-noise ratio (PSNR) values are 38 dB at least in restoring the noisy X-ray image. The sharpness of image’s edges increase in enhancing the blurred X-ray image. Furthermore, this paper proposes a VLSI architecture for accelerating the high-definition (HD) X-ray image (944 p) process. This paper implements the architecture in FPGA. The hardware cost is low because the computation of shock filter is low complex. To achieve the real-time processing specification, this paper uses a 5-series shock filter architecture to implement computation of HD X-ray image. This paper demonstrates a 944 p, 43.1-fps solution on 100 MHz with 133 k gate counts in Design Compiler, and with 2904 logic elements in FPGA.

3-D EIT Image Reconstruction Using a Block-Based Compressed Sensing Approach  [PDF]
Lan-Rong Dung, Chian-Wei Yang, Yin-Yi Wu
Journal of Computer and Communications (JCC) , 2014, DOI: 10.4236/jcc.2014.213005

Electrical impedance tomography (EIT) is a fast and cost-effective technique that provides a tomographic conductivity image of a subject from boundary current-voltage data. This paper proposes a time and memory efficient method for solving a large scale 3D EIT image reconstruction problem and the ill-posed linear inverse problem. First, we use block-based sampling for a large number of measured data from many electrodes. This method will reduce the size of Jacobian matrix and can improve accuracy of reconstruction by using more electrodes. And then, a sparse matrix reduction technique is proposed using thresholding to set very small values of the Jacobian matrix to zero. By adjusting the Jacobian matrix into a sparse format, the element with zeros would be eliminated, which results in a saving of memory requirement. Finally, we built up the relationship between compressed sensing and EIT definitely and induce the CS: two-step Iterative Shrinkage/Thresholding and block-based method into EIT image reconstruction algorithm. The results show that block-based compressed sensing enables the large scale 3D EIT problem to be efficient. For a 72-electrodes EIT system, our proposed method could save at least 61% of memory and reduce time by 72% than compressed sensing method only. The improvements will be obvious by using more electrodes. And this method is not only better at anti-noise, but also faster and better resolution.

A Hierarchical Grab Cut Image Segmentation Algorithm  [PDF]
Lan-Rong Dung, Yao-Ming Yang, Yin-Yi Wu
Journal of Computer and Communications (JCC) , 2018, DOI: 10.4236/jcc.2018.62005
Abstract: This paper aims to speed up a segmentation algorithm “Grab Cut” by separating the process of segmentation into hierarchical steps. The Grab Cut algorithm segments images by means of the color clustering concept and the process requires a lot of iteration for it to get converged. Therefore, it is a time-consuming process which we are interested in improving this process. In this study, we adopt the idea of hierarchical processing. The first step is to compute at low resolution to make the iteration much faster, and the second step use the result of the first step to carry on iteration at original resolution so that the total execution time can be reduced. Specifically speaking, segmentation of a low resolution image will lead to high-speed and similar-segmentation result to the segmentation at original resolution. Hence, once the iterations at low resolution have converged, we can utilize the parameters of segmentation result to initialize the next segmentation on original resolution. This way, the number of iteration of segmentation at original resolution will be reduced through the initialization of those parameters. Since the execution time of low resolution images is relatively short, the total hierarchical execution time will be reduced consequently. Also, we made a comparison among the four methods of reduction on image resolution. Finally, we found that reducing the number of basins by “Median Filter” resulted in best segmentation speed.
A Multiple Random Feature Extraction Algorithm for Image Object Tracking  [PDF]
Lan-Rong Dung, Shih-Chi Wang, Yin-Yi Wu
Journal of Signal and Information Processing (JSIP) , 2018, DOI: 10.4236/jsip.2018.91004
Abstract: This paper proposes an object-tracking algorithm with multiple randomly-generated features. We mainly improve the tracking performance which is sometimes good and sometimes bad in compressive tracking. In compressive tracking, the image features are generated by random projection. The resulting image features are affected by the random numbers so that the results of each execution are different. If the obvious features of the target are not captured, the tracker is likely to fail. Therefore the tracking results are inconsistent for each execution. The proposed algorithm uses a number of different image features to track, and chooses the best tracking result by measuring the similarity with the target model. It reduces the chances to determine the target location by the poor image features. In this paper, we use the Bhattacharyya coefficient to choose the best tracking result. The experimental results show that the proposed tracking algorithm can greatly reduce the tracking errors. The best performance improvements in terms of center location error, bounding box overlap ratio and success rate are from 63.62 pixels to 15.45 pixels, from 31.75% to 64.48% and from 38.51% to 82.58%, respectively.
Modified endoscopic submucosal dissection with enucleation for treatment of gastric subepithelial tumors originating from the muscularis propria layer
Chu Yin-Yi,Lien Jau-Min,Tsai Ming-Hung,Chiu Cheng-Tang
BMC Gastroenterology , 2012, DOI: 10.1186/1471-230x-12-124
Abstract: Background Gastric subepithelial tumors are usually asymptomatic and observed incidentally during endoscopic examination. Although most of these tumors are considered benign, some have a potential for malignant transformation, particularly those originating from the muscularis propria layer. For this type of tumor, surgical resection is the standard treatment of choice. With recent advent of endoscopic resection techniques and devices, endoscopic submucosal dissection (ESD) has been considered as an alternative way of treatment. The aim of this study is to demonstrate the feasibility of a modified ESD technique with enucleation for removal of gastric subepithelial tumors originating from the muscularis propria layer, and to evaluate its efficacy and safety. Methods From November 2009 to May 2011, a total of 16 patients received a modified ESD with enucleation for their subepithelial tumors. All tumors were smaller than 5 cm and originated from the muscularis propria layer of the stomach, as shown by endoscopic ultrasonography (EUS). The procedure was conducted with an insulated-tip knife 2. Patient’s demographics, tumor size and pathological diagnosis, procedure time, procedure-related complication, and treatment outcome were reviewed. Results Fifteen of the sixteen tumors were successful complete resection. The mean tumor size measured by EUS was 26.1 mm (range: 20–42 mm). The mean procedure time was 52 minutes (range: 30–120 minutes). Endoscopic features of the 4 tumors were pedunculated and 12 were sessile. Their immunohistochemical diagnosis was c-kit (+) stromal tumor in 14 patients and leiomyoma in 2 patients. There was no procedure-related perforation or overt bleeding. During a mean follow up duration of 14.8 months (range: 6–22 months), there was no tumor recurrence or metastasis. Conclusions Using a modified ESD with enucleation for treatment of gastric subepithelial tumors originating from the muscularis propria layer and larger than 2 cm, complete resection can be successfully performed without serious complication. It is a safe and effective alternative to surgical therapy for these tumors of 2 to 5 cm in size.
Effect of Diuretic Use on 30-Day Postdialysis Mortality in Critically Ill Patients Receiving Acute Dialysis
Vin-Cent Wu, Chun-Fu Lai, Chih-Chung Shiao, Yu-Feng Lin, Pei-Chen Wu, Chia-Ter Chao, Fu-Chang Hu, Tao-Min Huang, Yu-Chang Yeh, I-Jung Tsai, Tze-Wah Kao, Yin-Yi Han, Wen-Chung Wu, Chun-Cheng Hou, Guang-Huar Young, Wen-Je Ko, Tun-Jun Tsai, Kwan-Dun Wu
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0030836
Abstract: Background The impact of diuretic usage and dosage on the mortality of critically ill patients with acute kidney injury is still unclear. Methods and Results In this prospective, multicenter, observational study, 572 patients with postsurgical acute kidney injury receiving hemodialysis were recruited and followed daily. Thirty-day postdialysis mortality was analyzed using Cox's proportional hazards model with time-dependent covariates. The mean age of the 572 patients was 60.8±16.6 years. Patients with lower serum creatinine (p = 0.031) and blood lactate (p = 0.033) at ICU admission, lower predialysis urine output (p = 0.001) and PaO2/FiO2 (p = 0.039), as well as diabetes (p = 0.037) and heart failure (p = 0.049) were more likely to receive diuretics. A total of 280 (49.0%) patients died within 30 days after acute dialysis initiation. The analysis of 30-day postdialysis mortality by fitting propensity score-adjusted Cox's proportional hazards models with time-dependent covariates showed that higher 3-day accumulated diuretic doses after dialysis initiation (HR = 1.449, p = 0.021) could increase the hazard rate of death. Moreover, higher time-varying 3-day accumulative diuretic doses were associated with hypotension (p<0.001) and less intense hemodialysis (p<0.001) during the acute dialysis period. Background and Significance Higher time-varying 3-day accumulative diuretic dose predicts mortality in postsurgical critically ill patients requiring acute dialysis. Higher diuretic doses are associated with hypotension and a lower intensity of dialysis. Caution should be employed before loop diuretics are administered to postsurgical patients during the acute dialysis period.
Preoperative Proteinuria Is Associated with Long-Term Progression to Chronic Dialysis and Mortality after Coronary Artery Bypass Grafting Surgery
Vin-Cent Wu, Tao-Min Huang, Pei-Chen Wu, Wei-Jie Wang, Chia-Ter Chao, Shao-Yu Yang, Chih-Chung Shiao, Fu-Chang Hu, Chun-Fu Lai, Yu-Feng Lin, Yin-Yi Han, Yih-Sharng Chen, Ron-Bin Hsu, Guang-Huar Young, Shoei-Shen Wang, Pi-Ru Tsai, Yung-Ming Chen, Ting-Ting Chao, Wen-Je Ko, Kwan-Dun Wu, the NSARF Group
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0027687
Abstract: Aims Preoperative proteinuria is associated with post-operative acute kidney injury (AKI), but whether it is also associated with increased long- term mortality and end -stage renal disease (ESRD) is unknown. Methods and Results We studied 925 consecutive patients undergoing CABG. Demographic and clinical data were collected prospectively, and patients were followed for a median of 4.71 years after surgery. Proteinuria, according to dipstick tests, was defined as mild (trace to 1+) or heavy (2+ to 4+) according to the results of the dipstick test. A total of 276 (29.8%) patients had mild proteinuria before surgery and 119 (12.9%) patients had heavy proteinuria. During the follow-up, the Cox proportional hazards model demonstrated that heavy proteinuria (hazard ratio [HR], 27.17) was an independent predictor of long-term ESRD. There was a progressive increased risk for mild proteinuria ([HR], 1.88) and heavy proteinuria ([HR], 2.28) to predict all–cause mortality compared to no proteinuria. Mild ([HR], 2.57) and heavy proteinuria ([HR], 2.70) exhibited a stepwise increased ratio compared to patients without proteinuria for long–term composite catastrophic outcomes (mortality and ESRD), which were independent of the baseline GFR and postoperative acute kidney injury (AKI). Conclusion Our study demonstrated that proteinuria is a powerful independent risk factor of long-term all-cause mortality and ESRD after CABG in addition to preoperative GFR and postoperative AKI. Our study demonstrated that proteinuria should be integrated into clinical risk prediction models for long-term outcomes after CABG. These results provide a high priority for future renal protective strategies and methods for post-operative CABG patients.
Kidney function decline after a non-dialysis-requiring acute kidney injury is associated with higher long-term mortality in critically ill survivors
Chun-Fu Lai, Vin-Cent Wu, Tao-Min Huang, Yu-Chang Yeh, Kuo-Chuan Wang, Yin-Yi Han, Yu-Feng Lin, Ying-Jheng Jhuang, Chia-Ter Chao, Chih-Chung Shiao, Pi-Ru Tsai, Fu-Chang Hu, Nai-Kuan Chou, Wen-Je Ko, Kwan-Dun Wu, the National Taiwan University Hospital Study Group on Acute Renal Failure (NSARF)
Critical Care , 2012, DOI: 10.1186/cc11419
Abstract: This retrospective observational cohort study investigated non-dialysis-requiring AKI survivors in surgical intensive care units between January 2002 and June 2010. All longitudinal post-discharge serum creatinine measurements and information regarding end-stage renal disease (ESRD) and death were collected. We assessed the long-term outcomes of chronic kidney disease (CKD), ESRD and all-cause mortality beyond discharge.Of the 922 identified critically ill patients with a non-dialysis-requiring AKI, 634 (68.8%) patients who survived to discharge were enrolled. A total of 207 patients died after a median follow-up of 700.5 days. The median intervals between the onset of the AKI and the composite endpoints "stage 3 CKD or death", "stage 4 CKD or death", "stage 5 CKD or death", and "ESRD or death" were 685, 1319, 1743, and 2048 days, respectively. This finding shows a steady long-term decline in kidney function after discharge. Using the multivariate Cox proportional hazard model, we found that every 1 mL/min/1.73 m2 decrease from baseline estimated glomerular filtration rate (eGFR) of individuals who progressed to stage 3, 4, and 5 CKD increased the risks of long-term mortality by 0.7%, 2.3%, and 4.1%, respectively (all p < 0.05). This result indicates that the mortality risk increased significantly in a graded manner as kidney function declined from the baseline eGFR to advanced stages of CKD during the follow-up period.In critically ill patients who survive a non-dialysis-requiring AKI, there is a need for continuous monitoring and kidney function protection beyond discharge.Acute kidney injury (AKI) is a major contributor to morbidity and mortality in hospitalized patients [1]. Epidemiological studies have found that there is a gradual increase in the incidence of AKI no matter whether or not the patient requires dialysis [2-4]. Although many studies on patients with AKI who require dialysis have been performed, the literature is rather limited regarding AKI patien
Achalasia combined with esophageal intramural hematoma: Case report and literature review
Yin-Yi Chu, Kai-Feng Sung, Soh-Ching Ng, Hao-Tsai Cheng, Cheng-Tang Chiu
World Journal of Gastroenterology , 2010,
Abstract: A 62-year-old male patient was admitted to our hospital due to severe chest pain, odynophagia, and hematemesis. Chest computed tomography showed an esophageal submucosal tumor. Esophagogastroduodenoscopy (EGD) revealed a longitudinal purplish bulging tumor of the esophagus. Endoscopic ultrasound (EUS) showed a mixed echoic tumor with partial liquefaction from the submucosal layer. The patient was diagnosed with esophageal intramural hematoma as well as achalasia by upper gastrointestinal endoscopy, esophagography and esophageal manometry. The patient was managed conservatively with intravenous nutrition, and oral feeding was discontinued. Follow-up EGD and EUS showed complete recovery of the esophageal wall, and finally, the patient underwent endoscopic dilatation for achalasia. The patient was symptom free at the time when we wrote this manuscript.
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