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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.
91

Compression of Large-Scale Aerial Imagery : Exploring Set Redundancy Methods

Lüdeking, Solvej January 2023 (has links)
Compression of data has been historically always important; more data is gettingproduced and therefore has to be stored. While hardware technology advances,compression should be a must to reduce storage occupied and to keep the data intransmission as small as possible. Set redundancy has been developed in 1996 but has since then not received a lot ofattention in research. This paper tries to implement two set redundancy methods –the Max-Min-Predictive II and also the Intensity Mapping algorithm to see if thismethod could be used on large scale aerial imagery in the geodata field. After using the set redundancy methods, different individual image compressionmethods were applied and compared to the standard JPEG2000 in lossless mode.These compression algorithms were Huffman, LZW, and JPEG2000 itself. The data sets used were two images each taken from 2019, one pair with 60% overlap,the other with 80% overlap. Individual compression of images is still offering abetter compression ratio, but the set redundancy method produces results which areworth investigating further with more images in a set of similar images. This points to future work of compressing a larger set with more overlap and moreimages, which for greater potential matching should be overlaid more carefully toensure matching pixel values. / Datakomprimering har historiskt alltid varit viktigt; mer data än någonsin producerasoch behöver lagras. Trots teknologiska framsteg inom lagrings- och datateknologierär komprimering ett måste för att reducera mängden lagring som krävs och underlättavid överföringar genom att mindre filmängd måste skickas. Set redundancy utvecklades 1996, men har sedan dess inte fått så mycket uppmärksamhetinom forskning. Det här pappret försöker implementera två olika set redundancy-metoder – Max-Min-Predictive II och Intensity Mapping algoritmen, för att se omdenna metod kan användas på flygbilder från storskalig flygbildsinsamling. Efter användandet av set redundancy metoder på ett set av flygbilder, utnyttjadesandra bildkomprimeringsmetoder för enskilda bilder på resultatet, detta jämfördesmed den icke-förstörande JPEG2000 komprimeringen av originalbilderna. Komprimeringsalgoritmernasom användes på set redundancy-resultatet var Huffman, LZW,och JPEG2000. Det dataset som användes bestod av två par av bilder från 2019, där en hade överlapppå 60% och det andra paret på 80%. Individuell komprimering av dataseten gaven högre komprimeringsgrad än set redundancy metoder, men set redundancy har enskalningspotential när fler bilder läggs till i ett set, vilket är värt att undersöka vidare. Detta pekar på framtida arbeten där komprimering av större dataset med högreöverlapp mellan bilder, som med en högre geografisk korrekthet läses in ovanpåvarandra, kan testas.
92

7- and 12-Month-Olds' Intermodal Recognition of Affect: 7-Month-Olds are "Smarter" than 12-Month-Olds

Whiteley, Mark Oborn 30 June 2011 (has links) (PDF)
Research has shown that by 7-months of age infants demonstrate recognition of emotion by successfully matching faces and voices based on affect in an intermodal matching procedure. It is often assumed that once an ability is present the development of that ability has "ceased." Therefore, no research has examined if and how the ability to match faces and voices based on affect develops after the first 7-months. This study examined how the ability to match faces and voices based on affect changes from 7- to 12-months. Looking at infant's proportion of total looking time (PTLT) results showed that, consistent with previous research, 7-month-old infants looked significantly longer at the affectively congruent facial expression. However, 12-month- olds showed no matching of faces and voices. Further analyses showed that 7-month-olds also increased their looking to facial expressions while being presented with the affectively congruent vocal expression. Once again, 12-month-olds failed to show significant matching. That 7-month- olds were able to demonstrate matching while 12-month-olds failed to do so is possibly a result of 12-month-olds attending to other information. More research is needed to better understand how infants' recognition of affect and overall perceptual abilities change as they develop.
93

The Universal Design Paradigm: An Examination of Real-Time, C-Print, Meaning-for-Meaning Transcription and Individual Differences in Learning

Boone, Amanda 01 May 2014 (has links)
The intent of this thesis is to guide further research and discussion of C-Print, meaning-for-meaning transcription and its applications to today’s dynamic classroom settings under a Universal Design Paradigm. Evidence suggests that providing these captions can benefit Deaf and Hard of Hearing populations and also that concise, textual representations of information increase retention for average learners in multimedia settings. Individual differences were considered and low internal control participants did significantly better on exams when material was captioned compared to when it was not. They also tended to outperform high internal control participants on captioned material exams.
94

Investigating The Effectiveness Of Redundant Text And Animation In Multimedia Learning Environments

Chu, Shiau-Lung 01 January 2006 (has links)
In multimedia learning environments, research suggests that simultaneous presentation of redundant text (i.e. identical narration and on-screen text) may inhibit learning when presented with animation at the same time. However, related studies are limited to testing with cause-and-effects content information (e.g., Moreno & Mayer, 1999, 2002). This study examined the effects of redundant text on learners' memory achievement and problem solving ability. The study replicated and extended prior research by using descriptive, rather than cause-and-effect content information. The primary research questions were (a) does redundant text improve learning performance if learners are presented with instructional material that addresses subject matter other than cause-and-effect relationship? and (b) does sequential presentation of animation followed by redundant text help learning? To answer the research questions, five hypotheses were tested with a sample of 224 Taiwanese students enrolled in a college level Management Information System (MIS) courses at a management college in southern Taiwan. Statistically significant differences were found in memory achievement and problem solving test scores between simultaneous and sequential groups; while no statistically significant differences were found in memory achievement and problem solving test scores between verbal redundant and non-redundant groups. These results were supported by interviewees expressing difficulty in connecting animation and verbal explanation in the two sequential presentation groups. The interview responses also helped to explain why insignificant results were obtained when redundant and non-redundant verbal explanations with animation were presented simultaneously. In general, the results support previous research on the contiguity principle, suggesting that sequential presentations may lead to lower learning performance when animation and verbal explanation are closely related. The separation of the two types of information may increase cognitive load. In addition, the study found that impairment of redundant text was also affected by various learning characteristics, such as the structure of the instructional content and learners previous learning experiences. Recommendations for future study include: (a) research on various situations such as characteristics of the content, characteristics of learners, and difficulty of the instructional material that influences the effects of redundant text, and (b) research on prior learning experience that influences the effects of simultaneous redundant text presentations.
95

Graph Theoretic Modeling: Case Studies In Redundant Arrays Of Independent Disks And Network Defense

Nanda, Sanjeeb 01 January 2007 (has links)
Graph theoretic modeling has served as an invaluable tool for solving a variety of problems since its introduction in Euler's paper on the Bridges of Königsberg in 1736 . Two amongst them of contemporary interest are the modeling of Redundant Arrays of Inexpensive Disks (RAID), and the identification of network attacks. While the former is vital to the protection and uninterrupted availability of data, the latter is crucial to the integrity of systems comprising networks. Both are of practical importance due to the continuing growth of data and its demand at increasing numbers of geographically distributed locations through the use of networks such as the Internet. The popularity of RAID has soared because of the enhanced I/O bandwidths and large capacities they offer at low cost. However, the demand for bigger capacities has led to the use of larger arrays with increased probability of random disk failures. This has motivated the need for RAID systems to tolerate two or more disk failures, without sacrificing performance or storage space. To this end, we shall first perform a comparative study of the existing techniques that achieve this objective. Next, we shall devise novel graph-theoretic algorithms for placing data and parity in arrays of n disks (n ≥ 3) that can recover from two random disk failures, for n = p - 1, n = p and n = 2p - 2, where p is a prime number. Each shall be shown to utilize an optimal ratio of space for storing parity. We shall also show how to extend the algorithms to arrays with an arbitrary number of disks, albeit with non-optimal values for the aforementioned ratio. The growth of the Internet has led to the increased proliferation of malignant applications seeking to breach the security of networked systems. Hence, considerable effort has been focused on detecting and predicting the attacks they perpetrate. However, the enormity of the Internet poses a challenge to representing and analyzing them by using scalable models. Furthermore, forecasting the systems that they are likely to exploit in the future is difficult due to the unavailability of complete information on network vulnerabilities. We shall present a technique that identifies attacks on large networks using a scalable model, while filtering for false positives and negatives. Furthermore, it also forecasts the propagation of security failures proliferated by attacks over time and their likely targets in the future.
96

A Comparative Evaluation of Failover Mechanisms for Mission-critical Financial Applications in Public Clouds

Gustavsson, Albert January 2023 (has links)
Computer systems can fail for a vast range of reasons, and handling failures is crucial to any critical computer system. Many modern computer systems are migrating to public clouds, which provides more flexible resource consumption and in many cases reduced costs, while the migration can also require system changes due to limitations in the provided cloud environment. This thesis evaluates a few methods of achieving failover when migrating a system to a public cloud, with the main goal of finding a replacement for failover mechanisms that can only be used in self-managed infrastructure. A few different failover methods are evaluated by looking into different aspects of how each method would change an existing system. Two methods using \textit{etcd} and \textit{Apache ZooKeeper} are used for experimental evaluation where failover time is measured in two simulated scenarios where the primary process terminates and a standby process needs to be promoted to the primary status. In one scenario, the primary process is not able to notify other processes in the system before terminating, and in the other scenario, the primary process can release the primary status to another instance before terminating. The etcd and ZooKeeper solutions are shown to behave quite similarly in the testing setup, while the ZooKeeper solution might be able to achieve lower failover time in low-latency environments.
97

A redundancy software design for joint radio resource management system in a satellite-terrestrial based aeronautical communication network

Cheng, Yongqiang, Xu, Kai J., Hu, Yim Fun January 2013 (has links)
No / This paper presents a Master/Slave redundancy mechanism for the airborne Integrated Modular Radio to improve the reliability of the joint radio resource management (JRRM) system. The proposed mechanism adopts keep-alive heart beat messages and real time information synchronization to ensure a smooth switchover in the event of a platform failure. To enhance the scalability and decoupling of the system, the proposed hot swap solution makes the JRRM switchover transparent to both the higher layers and the lower layers. The experiment results and the performance obtained from the test-bed has proved the validity of the solution.
98

Renormalization of total sets of states into generalized bases with a resolution of the identity

Vourdas, Apostolos 23 June 2017 (has links)
Yes / A total set of states for which we have no resolution of the identity (a `pre-basis'), is considered in a finite dimensional Hilbert space. A dressing formalism renormalizes them into density matrices which resolve the identity, and makes them a `generalized basis', which is practically useful. The dresssing mechanism is inspired by Shapley's methodology in cooperative game theory, and it uses Mobius transforms. There is non-independence and redundancy in these generalized bases, which is quantifi ed with a Shannon type of entropy. Due to this redundancy, calculations based on generalized bases, are sensitive to physical changes and robust in the presence of noise. For example, the representation of an arbitrary vector in such generalized bases, is robust when noise is inserted in the coeffcients. Also in a physical system with ground state which changes abruptly at some value of the coupling constant, the proposed methodology detects such changes, even when noise is added to the parameters in the Hamiltonian of the system.
99

The Effects of Training, Modality, and Redundancy on the Development of a Historical Inquiry Strategy in a Multimedia Learning Environment

McNeill, Andrea Lynn 13 September 2004 (has links)
Research in the area of multimedia instruction has yielded results that indicate that learning is better when verbal information is presented auditorily instead of visually (i.e. modality effect) and when redundant on-screen text is removed from the instructional environment (i.e. redundancy effect). The present study aimed to extend these findings by exploring the effects of presentation modality and redundancy of verbal information on students' ability to apply and recall a historical inquiry strategy. Fifty-six students were randomly assigned to three treatment groups, which differed according to the presentation mode combination used to present the strategy instruction. Specifically, students received the instruction either as animation and narration, animation and text, or animation, narration, and text. The students were engaged in a multimedia strategy intervention for a total of five days, for approximately 25 minutes a day. Three strategy application tests (i.e., pre-test, post-test, maintenance test) and a recall test were used to measure the students' learning. Data attained through the strategy application tests and recall tests were analyzed using Analysis of Variance (ANOVA) procedures. The results of the study revealed significant differences in the training main effects analysis indicating that strategy instruction can be effectively provided in a multimedia learning environment. However, no significant differences were found for the modality and redundancy main effects indicating that there was no difference in strategy application or recall between the groups. Although the results did not provide the statistical significance that supports the literature on the modality and redundancy effects, the implications of the findings of the research provide several viable areas for future research. / Ph. D.
100

System Redundancy Evaluation for Steel Truss Bridge

Cao, Youyou 19 October 2015 (has links)
In current bridge practice, all tension members in a truss bridge are identified as fracture critical members which implies that a collapse is expected to occur once a member of this type fails. However, there are several examples which show that bridges have remained standing and shown little distress even after a fracture critical member was completely damaged. Due to the high inspection cost for fracture critical members, it would be beneficial to remove fracture critical designation from some tension members. This could be achieved via considering system redundancy. Since there is no clear guidance in existing codified provisions for assessing system redundancy, this research is undertaken to develop simplified analysis techniques to evaluate system redundancy in truss bridges. The proposed system redundancy analysis in this research starts with the identification of the most critical main truss members whose failure may significantly affect the system redundancy. The system redundancy is then measured by the remaining load capacity of a damaged bridge after losing one of the critical members. The bridge load capacity is checked using 3D models with nonlinear features that can capture the progression of yielding and buckling in a bridge system. The modeling techniques are validated through the case studies of the I-35W Bridge and one test span of the Milton-Madison Bridge. Reasonable correlations are demonstrated between the models and the measured data for these two bridges both in an undamaged and in a damaged state. The feasibility of the proposed methodology for system redundancy evaluation is examined by applying the methodology blindly to two other simple truss bridges. The application shows that the proposed methodology can efficiently measure the system redundancy. To improve the system redundancy, this research also proposes sample retrofit strategies for the four example bridges. / Ph. D.

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