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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.
81

Study and Implementation of a Web GIS with Flash

li, Hsin-cheng 20 January 2011 (has links)
Google announced Google Maps Service on June 2005, and they developed and used many technologies to solve performance balance issue that long existing in client-server GIS system, including Ajax, map data pre-processing, and browser's cookies system. OGC defined this mechanism as WMS-C. However, Ajax is a technology based on HTML and javascript, when processing mass spatial data, it could be the bottleneck of performace. Therefore, using browser plugin to improve performance on data processing is necessary. This paper discuss on WebGIS related technologies, including CGI, Java Applet, Ajax, Flash, and compare their weakness and strength, then we focus on analyzing Java Applet, Ajax, Flash. Flash provides better graphics processing abilities, smooth interactive operation, fast display performance, make it suitable to be a WebGIS platform. Flash also support multi-platform and multi-browser, and it can be deployed with the same programming code. So this study chooses Flash and it's language Action Script to develop WebGIS client, backend with Mapserver to publish map data. We also use TileCache to pre-process aerial images of National Sun Yat-sen University into image tiles. Also it is overlaid with Kaohsung district map as vector data. The actionscript in the WebGIS core library include classes like Map, View, Layer, TMSLayer, FeatureLayer. It is fully implemented as a Flash based WebGIS system. Lastly, we compare the Flash-based MapServer system with MapServer only regarding to there performance and interactivity. On loading vector data, flash performance is nearly equal to Mapserver. When vector panned, flash performs better because flash uses pre-loading image tiles, but Mapserver renders repeatly after every move. On interactivity, flash can directly zoom the map with mouse wheel, and it can shorten user¡¦s operating time. And flash can also dispaly animations like fade in, out, etc. After removing one single layer, the map still preserve the other layers, so users can handle the map information more precisely, and can reduce the loading of servers.
82

Storage Techniques in Flash Memories and Phase-change Memories

Li, Hao 2010 August 1900 (has links)
Non-volatile memories are an emerging storage technology with wide applica- tions in many important areas. This study focuses on new storage techniques for flash memories and phase-change memories. Flash memories are currently the most widely used type of non-volatile memory, and phase-change memories (PCMs) are the most promising candidate for the next-generation non-volatile memories. Like magnetic recording and optical recording, flash memories and PCMs have their own distinct properties, which introduce very interesting data storage problems. They include error correction, cell programming and other coding problems that affect the reliability and efficiency of data storage. Solutions to these problems can signifi- cantly improve the longevity and performance of the storage systems based on flash memories and PCMs. In this work, we study several new techniques for data storage in flash memories and PCMs. First, we study new types of error-correcting codes for flash memories – called error scrubbing codes –that correct errors by only increasing cell levels. Error scrubbing codes can correct errors without the costly block erasure operations, and we show how they can outperform conventional error-correcting codes. Next, we study the programming strategies for flash memory cells, and present an adaptive algorithm that optimizes the expected precision of cell programming. We then study data storage in PCMs, where thermal interference is a major challenge for data reliability. We present two new coding techniques that reduce thermal interference, and study their storage capacities and code constructions.
83

Critical Analysis and Review of Flash Points of High Molecular Weight Poly-functional C, H, N, O Compounds

Thomas, Derrick 2011 May 1900 (has links)
The research focuses on the critical review and prediction of flash points of high molecular weight compounds used mainly in the specialty chemical area. Thus far this area of high molecular weight specialty chemicals has not been thoroughly reviewed for flash point prediction; therefore critical review for accuracy of experimental values is difficult. Without critical review, the chance of hazards occurring in the processing and handling of these compounds increases. A reliable method for making predictions is important to efficiently review experimental values since duplicate experimentation can be time consuming and costly. The flash point is strongly correlated to the normal boiling point (NBP) but experimental NBP is not feasible for chemicals of high molecular weight. The reliability of existing NBP prediction methods was found inadequate for our compounds of interest therefore a new NBP prediction method was developed first. This method is based on ten simple group contributions and the molecular weight of the molecule. The training set included 196 high molecular weight C, H, N and O compounds. It produced an average absolute error (AAE) of 13K, superior to any other model tested so far. An accurate NBP is essential for critical review and new method development for flash point. A preliminary data analysis based on chemical family analysis allowed for detection of erroneous data points. These compounds were re-tested at a Huntsman facility. With a predicted normal boiling point, a new FP method that differentiates strong and iv weak hydrogen bonding compounds was developed. This was done because of the differences in entropy of vaporization for hydrogen bonding compounds. The training set consisted of 191 diverse C, H, N, O compounds ranging from 100 to 4000 g/mol in molecular weight. The test set consisted of 97 compounds of similar diversity. Both data sets produced an AAE of 5K and maximum deviation of 17.5K. It was also found that no substantial decomposition was found for these compounds at flash point conditions. These compounds appear to follow the same physical trends as lower molecular weight compounds. With this new method it is possible to critically review this class of chemicals as well as update NBP and other physical property data. / PDF file replaced 4-20-2012 at request of Thesis Office.
84

Implementation of Embedded LINUX with NOR Flash Memory

Chang, Yuan-Hao 02 June 2004 (has links)
Recently, Handheld devices are more and more popular. Most of them aim at the low price, small size, high computing power, and powerful functionalities. Therefore, the need for embedded operating systems in the market is absolutely vital. There are many embedded systems in the market, but embedded Linux has some advantages to be outstanding and widely accepted. For example, it has no proprietary problem and high portability, and is comparatively easy to be reconstructed and to develop new applications. Best of them all, it is open source software. Embedded systems are usually diskless systems. In order to keep permanent data in embedded Linux, using flash disk as its disk system is a widely adapted strategy. We use MTD (Memory Technology Devices) system to emulate flash memory as flash disk mounted into Linux virtual file system. This allows accessing flash memory with standard I/O operations without any extra effort. MTD system contains, ¡§user¡¨ and driver¡¨, two different modules. In driver modules, we use CFI (Common Flash Interface) to probe the flash chip and then partition it, while we use MTD BLOCK to emulate the flash partitions as block devices in user modules, and then mount them into Linux¡¦s virtual file system with JFFS2 (Journaling Flash File System version 2) type, which is a file system type specifically designed for flash devices according to the features of flash devices. The purpose of this thesis is to use MTD system to emulate Am29LV320DB flash chip as a flash disk in embedded Linux running on an ARM-based developing board, SMDK2410, designed by Samsung. I hope this porting can help the development of other advanced applications and provide an empirical platform for the research of embedded systems.
85

1.Pyrolytic Study of 3-Furylmethylazide 2.Synthesis and Chemistry of 5,6-Dimethylene-5,6-dihydrobenzofuran

Lin, Ya-Mei 31 July 2001 (has links)
Flash vacuum pyrolysis (FVP) of azidomethylthiophene, via a nitrene intermediate, gave a trimer (N,N`-trifurfurylidene-furfurylidene diamine). Use three kinds of methods to synthies benzofuran compound and gain the product by using the third method.
86

Macro-modeling and energy efficiency studies of file management in embedded systems with flash memory

Goyal, Nitesh 16 August 2006 (has links)
Technological advancements in computer hardware and software have made embedded systems highly affordable and widely used. Consumers have ever increasing demands for powerful embedded devices such as cell phones, PDAs and media players. Such complex and feature-rich embedded devices are strictly limited by their battery life- time. Embedded systems typically are diskless and use flash for secondary storage due to their low power, persistent storage and small form factor needs. The energy efficiency of a processor and flash in an embedded system heavily depends on the choice of file system in use. To address this problem, it is necessary to provide sys- tem developers with energy profiles of file system activities and energy efficient file systems. In the first part of the thesis, a macro-model for the CRAMFS file system is established which characterizes the processor and flash energy consumption due to file system calls. This macro-model allows a system developer to estimate the energy consumed by CRAMFS without using an actual power setup. The second part of the thesis examines the effects of using non-volatile memory as a write-behind buffer to improve the energy efficiency of JFFS2. Experimental results show that a 4KB write-behind buffer significantly reduces energy consumption by up to 2-3 times for consecutive small writes. In addition, the write-behind buffer conserves flash space since transient data may never be written to flash.
87

(¤@) Pyrolytic and Photolytic Studies of 2-Thiomethoxy- Styrylarenes (¤G) Pyrolytic Studies of 2-(3-Phenylpropenyl)anisole and 2-(1-Phenylpropenyl)anisole (¤T) Synthetic Study of Hexaazatriphenylene Derivatives

Hsu, Chen-Ping 30 June 2008 (has links)
¤@.Pyrolysis of 2-thiomethoxystyrylarenes 15a-c gave 2-(aryl-2-yl)benzo[b]arenes 22a-c and their isomers 23a-c and polycyclic aromatic hydrocarbons (PAH) 24a-c, respectively. Furthermore, pyrolysis of 15c also gave compounds 42¡B43¡B44 by breaking C-N single bond of 15c at higher temperature. In addition, photolysis of 15a-c gave photocyclic products 24a-c and 32a-c, respectively. ¤G.Pyrolysis of 2-(3-phenylpropenyl)anisole(18) and 2-(1-phenyl)anisole (19) gave 2-phenylbenzo[b]furan (13)¡Bbenzofuran (27)¡Bethylbenzene (28) and dibenzyl (29) as the main products. ¤T.Attempts to prepare hexaazatriphenylene derivatives 3 were carried by condensation between diamino dihydropyrazine compound 2 and hexaketocyclohexane (1).
88

(¤@) Pyrolytic and Photolytic Studies of o-Dimethylaminostyrylarenes and Its Derivatives (¤G) Pyrolytic Study of (2-Chlorostyryl)pyridines

Su, Li-Mei 15 July 2008 (has links)
¤@¡BFlash vacuum pyrolysis (FVP) of 2-dimethylaminostilbene and its derivatives via elimination of methyl radical followed by cyclization gave quinoline and 1-methylindole and 3-phenylquinoline and 3-phenylindole. On the other hand, Photolysis of 2-dimethylaminostilbene and its derivatives via electrocyclization gave 1-dimethylaminophenanthrene, phenanthrene, 2-(4-methoxy-phenyl)-1-methyl-1H- quinolin-4-one and 1-methyl-1H-indol-2-yl)phenylmethanone. Photolysis of 2,4'-dimethoxystilbene in acidic sulotion gave 1,6-dimethoxypheanthrene and 1-methoxypheanthrene and ketone compound via electrocyclization followed by [1,9] hydrogen shift. ¤G¡BFVP of 2-(2-chlorostyryl)pyridine gave benzo[f]quinolin, benzo[h]quinolin, on the other hand, FVP of 4-(2-chlorostyryl)pyridine gave different benzo[h]quinolin.
89

(¤@) Pyrolytic and Photolytic Studies of 2-(Dimethylamino)styrylarenes and 2-(Benzylmethylamino)styrylarenes (¤G) Pyrolytic Study of Benzoic 1,3-Dimethyl-2-indolyl Anhydride

Peng, Jheng-syong 27 July 2009 (has links)
¤@.Pyrolysis of 2-(N,N-dimethylamino)styrylarenes (29a-e) and 2-(N,N- benzylmethylamino)styrylarenes (30a-f) both gave 2-(ar-2-yl)- benzo[b]arenes 35a-f, 39a-e, their isomers 36a-e, 40a-e and the other products. On the other hand, photolysis of 29a-e gave electrocyclic products 2, 57b-e and 22a-e, respectively. However photolysis of 30a-f only gave the complicated and unknown compounds. ¤G.Pyrolysis of benzoic 1,3-dimethyl-2-indolyl anhydride (54) gave (1,3-dimethylindol-2-yl)phenylmethanone (63), 1,3-dimethylindole (65) and bis(1,3-dimethylindol-2-yl)methanone (66) as the main products.
90

Multimediaapplikation i Flash

Karlsson, Mats, Andersson, Johan January 2006 (has links)
<p>Vi gjorde ett frågespel på Internet åt ett företag som heter Nallegruppen & Co. Programmet vi använde för att göra detta var Macromedia Flash 8. Denna rapport beskriver hur vi gick tillväga för att lösa denna uppgift.</p>

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