1,720,964 research outputs found
A Study of Binocular Quality Assessment and Its Applications
No full text三維影像的客觀品質評估方法在三維多媒體相關的應用以及壓縮等相關標準中扮演著關鍵的角色。有關三維影像的品質評估的研究問題，相對於二維影像而言，面臨著許多嶄新的挑戰，例如非對稱式三維影像壓縮、深度知覺的感受以及虛擬視角的影像合成等。更甚者，目前廣泛被使用的二維品質評估的計算方法(例如PSNR與SSIM)並無法有效地處理這些新興的挑戰。其三維影像所計算出的品質評估結果與使用者對於三維影像的主觀評測分數並未能獲得高度一致的結果證明了此一論點。本論文為了因應這些新興的挑戰，除了原有的二維影像評估方式外，有關雙眼整合的視覺行為-雙眼結合以及雙眼頻率整合也首次被應用在三維影像的品質評估上。此一新提出的品質評估方式將藉由已公開的主觀評測分數資料庫進行驗證。實驗結果顯示本研究所提出的三維影像品質評估方式與主觀評測的分數具有顯著一致的結果，其相關係數可高達0.88。再者，我們發現所提出的新品質評估方式也可以有效地評估有關合成的三維影像的品質。因此，我們相信此類的雙眼視覺整合行為在發展三維影像客觀品質評估的過程中應扮演著重要的角色。The objective approaches to 3D image quality assessment play a key role in the development of compression standards and various 3D multimedia applications. The quality assessment of 3D images faces more new challenges, such as asymmetric stereo compression, depth perception, and virtual view synthesis, than its 2D counterparts. Moreover, the widely used 2D image quality metrics (e.g. PSNR and SSIM) cannot be directly applied to deal with these newly introduced challenges. This statement can be verified by the low correlation between the computed objective measures and the subjectively measured mean opinion scores (MOS''s), when 3D images are the tested targets. In order to meet these newly introduced challenges, in this work, besides traditional 2D image metrics, the binocular integration behaviors - the Binocular Combination and the Binocular Frequency Integration (BFI), are utilized as the bases for measuring the quality of stereoscopic 3D images. The effectiveness of the proposed metrics is verified by conducting subjective evaluations on publicly available stereoscopic image databases. Experimental results show that significant consistency could be reached between the measured MOS and the proposed metrics, in which the correlation coefficient between them can go up to 0.88. Furthermore, we found that the proposed metrics can also address the quality assessment of the synthesized color-plus-depth 3D images well. Therefore, it is our belief that the binocular integration behaviors are important factors in the development of objective quality assessment for 3D images.摘要ii
Abstract iii
1 Introduction 1
2 Previous Research Works in 2D/3D IQA Models 5
2.1 Subjective Evaluation Methods . . . . . . . . . . . . . . . . . . . . . . . 6
2.2 2D IQA Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2.1 The Gap between 2D IQA Models and 3D IQA Models . . . . . . 11
2.3 3D IQA Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.3.1 Color Information only . . . . . . . . . . . . . . . . . . . . . . . 11
2.3.2 Color plus Disparity Information . . . . . . . . . . . . . . . . . . 13
2.3.3 Comparison among 3D IQA Models . . . . . . . . . . . . . . . . 14
3 Related Studies of Binocular Visual System 16
3.1 The Visual Response of HVS . . . . . . . . . . . . . . . . . . . . . . . . 16
3.2 The Two Visual Pathways of Binocular Visual System . . . . . . . . . . 17
3.3 Neural Mechanisms of Binocular Combination Behaviors . . . . . . . . . 18
3.3.1 The Binocular Brightness Combination . . . . . . . . . . . . . . 18
3.4 Visual Information Processing from V1 to V4 . . . . . . . . . . . . . . . 21
4 The Proposed Computational Framework 23
4.1 Difference-of-Gaussian Decomposition of Stereo Images . . . . . . . . . 24
4.2 The Binocular Combination and Frequency Integration . . . . . . . . . . 26
4.3 Frequency Integrated Quality Metrics (FI-Metrics) . . . . . . . . . . . . 27
5 Experimental Results 29
5.1 Subjective Data Collection of CML Database . . . . . . . . . . . . . . . 29
5.2 The Number of Frequency bands for FI-metrics . . . . . . . . . . . . . . 33
5.3 The Performance Evaluation of FI-Metrics . . . . . . . . . . . . . . . . . 34
5.4 The Quality Assessment of Symmetric-Stereo Compression . . . . . . . . 36
5.5 The Quality Assessment of Asymmetric-Stereo Compression . . . . . . . 37
5.6 The Quality Assessment of All Compression Combinations . . . . . . . . 38
5.7 The Correlation between the Picture Quality Measure and the Depth Quality Measure . . . . 38
5.8 The Indirect Quality Assessment of Synthesized Stereo Images . . . . . . 40
5.9 The 3D IQA Model Comparisons on CML database . . . . . . . . . . . . 42
5.10 Proposed Metrics on 3D Video Compression Database . . . . . . . . . . 43
5.11 Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
5.12 Binocular Perceptual RD Performance of Asymmetric-Stereo Compression 48
5.13 Proposed Metrics for Different Distortion Types . . . . . . . . . . . . . . 49
6 Discussions and Conclusion 52
Bibliography 5
Computational and Experimental Study on the Performance of Wind Energy Marine Unit
No full text本研究主要利用計算流體力學模擬可變攻角以及可變襟翼葉片的WEMU(Wind Energy Marine Unit)在水槽中的性能表現，觀察在不同葉片幾何外型以及葉片數目下的性能差異，再針對各種不同類型的葉片所組合而成的葉輪加以分析比較。藉助於CFD計算軟體FLUENT模擬WEMU在固定入流下運轉，計算其性能表現，紊流模型採用Spalart-Allmaras之方程式，計算時在X方向設定入流，並在葉輪轉子區域利用MRF(Moving Reference Frame)法模擬葉輪旋轉，利用給定不同周速比，分別計算出不同葉片組合之葉輪所產生之扭力以及功率；為驗證數值模擬結果，在實驗部分，利用拖車將WEMU實驗裝置在水槽中拖曳，使葉輪轉子旋轉，並且使用扭力計以及轉速計量測出扭力以及轉速之平均輸出，計算與實驗之結果發現葉片數目越多，葉輪所產生的力矩以及功率越大，而葉片襟翼可變形的葉輪比固定式襟翼的葉輪所產生的扭力以及功率較差。ABSTRACT
This study discusses the performance of Wind Turbine Marine Unit (WEMU) with variable pitch angle and deformable flap, as determined by computational fluid dynamics (CFD) and water tank experiment. Different types of rotor with different geometric and blade numbers were compared and analyzed. The CFD software FLUENT was used to simulate the turbine rotating in the flow field. Numerical computation was run using the Spalart-Allmaras turbulence model. The inlet direction was set along the X-axis from negative X to positive X. The moving reference frame (MRF) method was used to simulated the rotation of rotor zone , and different tip speed ratio (TSR) were specified to calculate the torque and power generated from different types of blade rotors. To verify the CFD results, a tow carriage was used to pull the WEMU in the water tank in order to simulate water flow through the turbine. When the turbine started running, the average torque and rotation speed were measured by torque meter and tachometer respectively. The results showed that the higher the blade number set, the greater the torque and power derived. It was also found that the deformation of the flaps resulted in a decrease in torque and power, contrary to what had been expected
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
