1,721,045 research outputs found
Super-Resolution Image Restoration from Image Sequence
No full text超解析度有許多種類的應用，為了要使低解析度的內容呈現在高解析度的顯示器上，市場對於超解析度的演算法有著迫切需求。本論文中提出了一個基於凸集投影的超解析度演算法。在超解析度處理中，會給定一個低品質的影像序列，而輸出我們想要得到的高品質影像。我們採用頻率域方法來估計畫面間的運動位移，也使用對數影像處理來增強輸出影像的結果。The field of super-resolution has a wide area of applications. In order to display relatively low-quality content on high-resolution displays, the need for super resolution algorithms has become an urgent market priority. A method of super-resolution based on project-onto-convex-sets (POCS) is proposed in this thesis. In the super-resolution process, a set of low-quality images is given, and a single improved-resolution image is desired. We adopt frequency-domain method to estimate motion and enhance the result of high-resolution image by logarithmic image processing model.口試委員會審定書 i
誌謝 ii
中文摘要 iii
ABSTRACT iv
CONTENTS v
LIST OF FIGURES vii
Chapter 1 Introduction 1
1.1 Motivation 1
1.2 Super Resolution 1
1.3 Single-Frame Restoration 4
1.4 Multi-Frame Restoration 4
1.5 Applications of Super-Resolution 5
Chapter 2 Related Works 6
2.1 How Is Super-Resolution Possible? 6
2.2 Observation Model 7
2.2.1 Down-sampling 8
2.2.2 Warping 9
2.2.3 Blurring 10
2.3 The Point Spread Function 11
2.4 Sub-Pixel Shift 12
Chapter 3 State-of-the-Art SR Methods 14
3.1 Frequency Domain Methods 14
3.2 Spatial Domain Methods 16
3.2.1 Bicubic Interpolation 16
3.2.2 Iterative Back-Projection Techniques 17
3.2.3 Projection Onto Convex Sets 18
Chapter 4 Methodology 20
4.1 Overview 20
4.2 Motion Estimation 21
4.3 Project onto Convex Sets 23
4.3.1 Up-Sample 24
4.3.2 Shift the Up-Sampled Low-Resolution Images 24
4.3.3 Combine the Up-Sampled Images. 25
4.3.4 Linear Filtering and Iteration until It Converges 26
4.4 Image Enhancement 27
Chapter 5 Experimental Results 29
5.1 Overview 29
5.2 Experimental Environment 29
5.3 Evaluation Results 30
Chapter 6 Conclusion and Future Work 48
REFERENCES 4
Simulation and Verification Raman Enhancement with Silver and Gold Grating
No full text拉曼增強效應是目前理論上與研究上熱門的議題，並廣泛的被應用在各個領域，如生物上的蛋白質研究、醫藥領域的免疫檢測等，這都是因為拉曼增強效應具有快速且準確分析單分子的能力，也因此各種拉曼增強的技術不斷推陳出新，如表面增強拉曼效應、針尖拉曼增強效應等，但至目前為止，能夠將拉曼增強效應「量化」的研究尚無人能夠突破，即拉曼增強的倍數仍然無法定量。本篇論文的目的是透過實驗室新開發的光學模擬計算方法，並搭配合適的實驗環境及量測技巧，期望在拉曼量測下，可以得到訊號增強倍數量化的結果。
本實驗室光學計算方法主要針對週期性光柵結構做模擬，我們發現光柵會因其材質不同、線寬週期不同、深度不同或代測物之介電常數不同，而導致光柵周圍局部電磁場的分佈不一樣，透過模擬，我們找到一個能夠將能量放大的光柵環境，這個環境是設法將水這個物質引入光柵溝槽中，藉由水-介電常數大的特質，將垂直入射光柵的光侷限在水中，也就是說入射能量在水中會產生共振增強的現象，若待測物的分子存在水中，此分子即可得到訊號的放大，這個現象在論文本文中會詳細說明，而依據此模擬，我設計了拉曼即時(real-time)的量測方法來達成此模擬條件。在實驗過程中我們另外發現，在光柵表面有自組裝單層薄膜的產生對於拉曼訊號增強有一定的影響，因此，為驗證此現象，我分別在金光柵及銀光柵表面生成化合物，並加水覆蓋在其上，在此環境下做拉曼即時量測，我們確實得到了訊號增強的結果。在模擬和實驗的數據比較中，我們雖然無法精準預測實驗結果，但模擬和實驗兩者仍有一定的相依性存在。Raman scattering enhancement has been a popular research topic and applied to various fields such as biological protein research and medical immune examination. Raman scattering have the character of rapidly and precisely analyzing molecular structure. Moreover, new techniques of Raman scattering have constantly been invented including surface-enhanced Raman scattering (SERS) and tip-enhanced Raman scattering (TERS) etc. However, there is no research dealing with quantifying the effect of Raman enhancement, that is to say that the enhancement of Raman signal cannot be quantitatively determined. Therefore, under proper experimental environment and gauging skills, the research aims to quantify the enhancement of Raman signal using our lab’s newly developed Optical Computing Method.
The newly developed Optical Computing Method is to simulate periodic grating structure first. We found that grating due to their different materials, different line width period, depth, or different dielectric constant of measuring target, which lead to different local electromagnetic field distribution around grating. By simulating grating structure, we discover a grating environment which can enhance signal. Because of the large dielectric constant of water, making water into the trench of grating will restrict the vertical incident light within the water. The indecent energy will generate resonance in the water and thereby enhance signal. The more detailed phenomena are articulated in the thesis. Based on the simulation, I designed a real-time gauging method to create the simulated condition. During the experiment, I noticed that the self-assemble monolayer (SAM )on the surface of grating influences the effect of Raman enhancement. Therefore, I produced compound on the surface of golden grating and silver grating respectively and cover them by water. Doing the Raman real-time gauging in the aforementioned environment successfully generated the result of signal enhancement
SiGe Epitaxial Growth by Ultra-high Vacuum Chemical Vapor Deposition and the Advanced Device Applications
No full text於本論文中，超高真空化學氣相沉積矽鍺磊晶技術被詳細的探討。我們成長矽鍺量子點與奈米環狀結構以供光偵測器元件等先進光學元件應用開發，而矽鍺量子井以及矽鍺漸進層結構則被設計來提供金氧半場效電晶體元件以及絕緣層閘極場校電晶體元件等先進電子元件的開發。
於本論文的第一部份，矽鍺量子井與矽鍺量子點這兩種已經歷史悠久的矽鍺奈米微結構的生長機制將被再次討論，特別是載流氣體對矽鍺量子井與量子點結構的生長影響。氫原子表面覆蓋現象在矽鍺量子井與量子點結構的生長中扮演很重要的角色，特別是會影響到矽鍺奈米結構中的鍺濃度以及應變分布。除此之外，這兩種奈米結構在元件上的應用也被充份的討論。利用在Si(100)，Si(110)與Si(111)三種基板上製作的金氧半場效電晶體在本次論文中亦被開發。等效質量的差異導致了在這三種基板上製作之元件的載子遷移率不同。另一方面，利用多層量子點結構製作的紅外光偵測器特性也在此部份被討論。
在矽鍺量子井與矽鍺量子點之生長與元件應用介紹後，我們利用類似的概念開發出矽鍺奈米環狀結構。兩種生長機制：矽原子表面擴散與鍺原子外擴散現象分別被建構在於六百度生長與於五百度生長的矽鍺奈米環狀結構上。利用鍺原子外擴散現象所製作的矽鍺奈米環狀結構，由於對環狀結構的深度以及邊緣的鍺濃度具有較好的控制性，被我們認為是比較適合於開發未來新型光偵測器等先進元件應用。而除了開發出此結構外，我們亦同時開發出在Si(100)，Si(110)與Si(111)三種基板上的矽鍺奈米環狀結構。利用改變底部基板，我們可以控制矽鍺奈米環狀結構的基底形狀，藉以得到更多光學元件的應用。
在本論文的第三部份，我們開發出了具有目前世界紀錄二維電子氣載子遷移率的高速元件，並進一步的將此紀錄往前推進。此項高速元件在載子濃度於1.5×1011 /cm2時，具有約1.6×106 cm2/Vs的二維電子氣載子遷移率。另一方面，我們更進一步的將此概念開發成可同時具有二維電子氣以及二維電洞氣載子遷移率的互補元件。P型通道場效電晶體的特性以及反用換流器也同時被開發成功。除此之外，我們也討論了對於二維電子氣密度以及二維電子氣載子遷移率的限制性。各種在矽鍺奈米結構內的散射現象，包括雜質、背景雜質、介面粗糙度、還有線差排密度等，都可以很直接的降低我們的二維電子氣載子遷移率。而藉由這部份的發現，我們也成功將我們二維電子氣載子遷移率的紀錄推進到2×106 cm2/Vs，並在可預期的未來，我們還有更多進步空間。
最後一個部份裡，我們討論了在鍺基板上成長矽的生長機制。一個與一般在矽基板上生長鍺狀況不同，從三維生長回歸到二維生長的機制，被第一次在鍺基板上成長矽的情形中發現。這一連串的生長分成三個階段，首先，矽量子點會先出現在鍺基板表面。在持續的矽沉積後，一種奈米環狀結構將會取代原本的矽量子點。而最後，整個矽表面將會變平，回歸到二維的生長當中。這種生長機制，推測是來自於拉伸應變可以增強矽原子在表面的表面擴散效應，並增進側向的成長，從而形成從三維生長回歸到二維生長的機制。這種平坦狀的矽磊晶層，對於先進的光電以及奈米電子元件開發，具有非常大的助益。SiGe epitaxial growth by ultra-high vacuum chemical vapor deposition has been investigated in this dissertation. The SiGe quantum dots (QDs) and nanorings were fabricated for the applications of the photodetectors, while the SiGe quantum wells (QWs) and the SiGe graded buffer layers (GBLs) were fabricated for the applications of the metal-oxide-semiconductor field effect transistors (MOSFETs) and the insulator-gate field effect transistors (IGFETs).
In the first part of this thesis, the growth mechanisms of the SiGe QWs and SiGe QDs have been discussed. The carrier gas effects on the growth of the QWs and QDs are also discussed. The hydrogen passivation, which can influence the Ge concentration and the strain in the SiGe nanostructures, plays a crucial role in the SiGe QWs and SiGe QDs growth. Moreover, the device applications are also introduced. The MOSFETs fabricated from the SiGe QWs grown on Si(100), Si(110), and Si(111) have been discussed. The higher mobility in the direction of Si and SiGe is due to the smaller conductive effective mass. The quantum dot infrared photodetectors (QDIPs) made by the multi-layer SiGe QDs substrate have also been demonstrated.
After the discussion on the growth of the SiGe QWs and QDs, the SiGe nanorings have also been investigated. The Si surface diffusion mechanism and the Ge out-diffusion mechanism were proposed for nanorings formation at 600oC and 500oC, respectively. The SiGe nanorings created by Ge out-diffusion show controllable depth and well-defined Ge content at edges. The novel nanoring structures can be used in new optoelectronic devices. Moreover, the surface orientation effects on SiGe QDs and nanorings formation are investigated. The base shapes of SiGe QDs and nanorings can be controlled by different surface orientation.
In the third part of this thesis, the two dimensional electron gas (2DEG) devices with the world record high 2DEG mobility have been investigated. The 2DEG in a Si QW on SiGe GBLs with the world record high mobility of 1.6×106 cm2/Vs at carrier densities n~1.5×1011 /cm2. On the other hand, the complementary devices on an undoped Si/SiGe substrate where both 2D electrons and holes have also been investigated. A p-channel FET is characterized and the operation of an inverter is demonstrated. Moreover, the limitations of the two dimensional electron densities and 2DEG mobility have been discussed. The scattering from remote dopants, background impurities, interface roughness, and threading dislocations can all degrade the mobility in SiGe heterostructures. Based on the knowledge above, we have successfully improved the 2DEG mobility to 2×106 cm2/Vs by changing the substrate structures.
Finally, the growth mechanism of the Si on Ge growth was investigated. The transition from 3-dimensional (3D) to 2-dimensional (2D) growth for Si on Ge, which is different from the Ge on Si case, was observed for the first time. The Si quantum dots can be observed in the initial Si growth on Ge. With the increasing Si deposition, the ring-like structures appeared. Finally, the flat surface without any nanostructures above can be observed. The tensile strain to enhance surface mobility of Si atoms favors proposedly the lateral growth, and leads to the three to two dimensional growth. The flatter Si layer growth directly on Ge can be used for the application of novel nanoelectronics and optoelectronics devices
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
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