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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Finding Corresponding Regions In Different Mammography Projections Using Convolutional Neural Networks / Prediktion av Motsvarande Regioner i Olika Mammografiprojektioner med Faltningsnätverk

Eriksson, Emil January 2022 (has links)
Mammography screenings are performed regularly on women in order to detect early signs of breast cancer, which is the most common form of cancer. During an exam, X-ray images (called mammograms) are taken from two different angles and reviewed by a radiologist. If they find a suspicious lesion in one of the views, they confirm it by finding the corresponding region in the other view. Finding the corresponding region is a non-trivial task, due to the different image projections of the breast and different angles of compression needed during the exam. This thesis explores the possibility of using deep learning, a data-driven approach, to solve the corresponding regions problem. Specifically, a convolutional neural network (CNN) called U-net is developed and trained on scanned mammograms, and evaluated on both scanned and digital mammograms. A model based method called the arc model is developed for comparison. Results show that the best U-net produced better results than the arc model on all evaluated metrics, and succeeded in finding the corresponding area 83.9% of times, compared to 72.6%. Generalization to digital images was excellent, achieving an even higher score of 87.6%, compared to 83.5% for the arc model.
12

Procenta v úlohách matematické olympiády, korespondenčních seminářů a výzkumů PISA, TIMSS / Percentage tasks in a mathematical olympiad, in corresponding seminars, and in PISA and TIMSS tests.

TOMANOVÁ, Denisa January 2014 (has links)
Diploma thesis includes information about percentages, mathematical olympiad, mathematical corresponding seminars and PISA ant TIMSS tests. The first, theoretical part describes historical development of mathematical olympiad and its organization, the history of mathematical corresponding seminars and list of current seminars for primary school students. The second part of the diploma thesis consists of the collection of tasks examples with percentages that appear in mathematical olympiad, mathematical corresponding seminars and PISA and TIMSS tests.
13

An interfacial engineering approach towards two-dimensional porous carbon hybrids for high performance energy storage and conversion

Lu, Chenbao, Liu, Shaohua, Zhang, Fan, Su, Yuezeng, Zou, Xiaoxin, Shi, Zhan, Li, Guodong, Zhuang, Xiaodong 17 July 2017 (has links) (PDF)
In order to improve the performance and fundamental understanding of conducting polymers, development of new nanotechnologies for engineering aggregated states and morphologies is one of the central focuses for conducting polymers. In this work, we demonstrated an interfacial engineering method for the rational synthesis of a two-dimensional (2D) polyaniline (PANI) nano-array and its corresponding nitrogen-doped porous carbon nanosheets. Not only was it easy to produce a sandwich-like 2D morphology, but also the thickness, anchored ions and produced various metal phosphides were easily and rationally engineered by controlling the composition of the aqueous layer. The novel structural features of these hybrids enabled outstanding electrochemical capacitor performance. The specific capacitance of the as-produced diiron phosphide embedded nitrogen-doped porous carbon nanosheets was calculated to be as high as 1098 F g−1 at 1 A g−1 and an extremely high specific capacitance of 611 F g−1 at 10 A g−1, outperforming state-of-the-art performance among porous carbon and metal-phosphide-based supercapacitors. We believe that this interfacial approach can be extended to the controllable synthesis of various 2D material coupled sandwich-like hybrid materials with potential applications in a wide range of areas.
14

An Efficient Method for Computing Excited State Properties of Extended Molecular Aggregates Based on an Ab-Initio Exciton Model

Morrison, Adrian Franklin January 2017 (has links)
No description available.
15

使用光束調整法與多張影像做相機效正與三維模型重建 / Using bundle adjustment for camera Calibration and 3D reconstruction from multiple images

蔡政君, Tsai, Jeng Jiun Unknown Date (has links)
自動化三維建模需要準確的三維點座標,而三維點的位置則依賴高精度的對應點,因此對應點的尋找一直是此領域的研究議題,而使用稀疏光束調整法(SBA:Sparse Bundle Adjustment)來優化相機參數也是常用的作法,然而若三維點當中有少數幾個誤差較大的點,則稀疏光束調整法會受到很大的影響。我們採用多視角影像做依據,找出對應點座標及幾何關係,在改善對應點位置的步驟中,我們藉由位移三維點法向量來取得各種不同位置的三維補綴面(3D patch),並根據投影到影像上之補綴面的正規化相關匹配法(NCC:Normalized Cross Correlation)來改善對應點位置。利用這些改善過的點資訊,我們使用稀疏光束調整法來針對相機校正做進一步的優化,為了避免誤差較大的三維點影響到稀疏光束調整法的結果,我們使用穩健的計算方法來過濾這些三維點,藉由此方法來減少再投影誤差(reprojection error),最後產生較精準的相機參數,使用此參數我們可以自動化建出外型架構較接近真實物體的模型。 / Automated 3D modeling of the need for accurate 3D points, and location of the 3D points depends on the accuracy of corresponding points, so the search for corresponding points in this area has been a research topic, and the use of SBA(Sparse Bundle Adjustment) to optimize the camera parameters is also a common practice, however, if there are a few more error 3D points, the SBA will be greatly affected. In this paper, we establish the corresponding points and their geometry relationship from multi-view images. And the 3D patches are used to refine point positions. We translate the normal to get many patches, and project them into visible images. The NCC(Normalized Cross Correlation) values between patches in reference image and patches in visible image are used to estimate the best correspondence points. And they are used to get better camera parameters by SBA(sparse bundle adjustment). Furthermore, it is because that it usually exist outliers in the data observed, and they will influence the results by using SBA. So, we use our robust estimation method to resist the outliers. In our experiment, SBA is used to filter some outliers to reduce the reprojection error. After getting more precise camera parameters, we use them to reconstruct the 3D model more realistic.
16

基於多視角幾何萃取精確影像對應之研究 / Accurate image matching based on multiple view geometry

謝明龍, Hsieh, Ming Lung Unknown Date (has links)
近年來諸多學者專家致力於從多視角影像獲取精確的點雲資訊,並藉由點雲資訊進行三維模型重建等研究,然而透過多視角影像求取三維資訊的精確度仍然有待提升,其中萃取影像對應與重建三維資訊方法,是多視角影像重建三維資訊的關鍵核心,決定點雲資訊的形成方式與成效。 本論文中,我們提出了一套新的方法,由多視角影像之間的幾何關係出發,萃取多視角影像對應與重建三維點,可以有效地改善對應點與三維點的精確度。首先,在萃取多視角影像對應的部份,我們以相互支持轉換、動態高斯濾波法與綜合性相似度評估函數,改善補綴面為基礎的比對方法,提高相似度測量值的辨識力與可信度,可從多視角影像中獲得精確的對應點。其次,在重建三維點的部份,我們使用K均值分群演算法與線性內插法發掘潛在的三維點,讓求出的三維點更貼近三維空間真實物體表面,能在多視角影像中獲得更精確的三維點。 實驗結果顯示,採用本研究所提出的方法進行改善後,在對應點精確度的提升上有很好的成效,所獲得的點雲資訊存在數萬個精確的三維點,而且僅有少數的離群點。 / Recently, many researchers pay attentions in obtaining accurate point cloud data from multi-view images and use these data in 3D model reconstruction. However, this accuracy still needs to be improved. Among these researches, the methods in extracting the corresponding points as well as computing the 3D point information are the most critical ones. These methods practically affect the final results of the point cloud data and the 3D models so constructed. In this thesis, we propose new approaches, based on multi-view geometry, to improve the accuracy of corresponding points and 3D points. Mutual support transformation, dynamic Gaussian filtering, and similarity evaluation function were used to improve the patch-based matching methods in multi-view image correspondence. Using these mechanisms, the discrimination ability and reliability of the similarity function and, hence, the accuracy of the extracted corresponding points can be greatly improved. We also used K-mean algorithms and linear interpolations to find the better 3D point candidates. The 3D point so computed will be much closer to the surface of the actual 3D object. Thus, this mechanism will produce highly accurate 3D points. Experimental results show that our mechanism can improve the accuracy of corresponding points as well as the 3D point cloud data. We successfully generated accurate point cloud data that contains tens of thousands 3D points, and, moreover, only has a few outliers.
17

An interfacial engineering approach towards two-dimensional porous carbon hybrids for high performance energy storage and conversion

Lu, Chenbao, Liu, Shaohua, Zhang, Fan, Su, Yuezeng, Zou, Xiaoxin, Shi, Zhan, Li, Guodong, Zhuang, Xiaodong 17 July 2017 (has links)
In order to improve the performance and fundamental understanding of conducting polymers, development of new nanotechnologies for engineering aggregated states and morphologies is one of the central focuses for conducting polymers. In this work, we demonstrated an interfacial engineering method for the rational synthesis of a two-dimensional (2D) polyaniline (PANI) nano-array and its corresponding nitrogen-doped porous carbon nanosheets. Not only was it easy to produce a sandwich-like 2D morphology, but also the thickness, anchored ions and produced various metal phosphides were easily and rationally engineered by controlling the composition of the aqueous layer. The novel structural features of these hybrids enabled outstanding electrochemical capacitor performance. The specific capacitance of the as-produced diiron phosphide embedded nitrogen-doped porous carbon nanosheets was calculated to be as high as 1098 F g−1 at 1 A g−1 and an extremely high specific capacitance of 611 F g−1 at 10 A g−1, outperforming state-of-the-art performance among porous carbon and metal-phosphide-based supercapacitors. We believe that this interfacial approach can be extended to the controllable synthesis of various 2D material coupled sandwich-like hybrid materials with potential applications in a wide range of areas.
18

Towards Achieving Higher Product Selectivity by Controlling Photoreactivity

George, Sobiya January 2021 (has links)
No description available.
19

Písňové tabule ve výuce hudební výchovy na 1. stupni ZŠ / Singing board at musical education on the first degree of basic schools

MARTENKOVÁ, Kateřina January 2018 (has links)
Diplomová práce přináší návrh písňových tabulí obsahujících písně, které lze využít při výuce intonační výchovy v hodinách hudební výchovy na prvním stupni základní školy. Ke každému ročníku je vytvořen výběr písní, které se týkají problematiky intonační výchovy příslušného ročníku. Pod notovou osnovou písně je uvedeno, kde se nachází první stupeň dané tóniny, podle které se žáci mohou orientovat, a text písně, který je psán drobným písmem, aby žákům nenapověděl, která píseň k této melodii patří, a který slouží jako případná pomůcka pro učitele.
20

Návrh soustavy CZT a tepelných zdrojů / Design of district heating system and heat sources

Kluzová, Ivana January 2018 (has links)
District heating, heat sources, cogeneration, boiler, biomass

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