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T Ime –F Requency a Nalysis U Sing N Eural N Etworks

Thesis Info

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External Link

Author

Shafi, Imran

Program

PhD

Institute

University of Engineering and Technology

City

Taxila

Province

Punjab

Country

Pakistan

Thesis Completing Year

2009

Thesis Completion Status

Completed

Subject

Applied Sciences

Language

English

Link

http://prr.hec.gov.pk/jspui/handle/123456789/837

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727537918

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The thesis is divided in three parts. In the rst part, it explores and discusses the diversity of concepts and motivations for obtaining good resolution and highly concentrated time–frequency distributions (TFDs) for the research community. The description of the methods used for TFDs'' objective assessment is provided later in this part. In the second part, a novel multi–processes ANN based framework to obtain highly concentrated TFDs is proposed. The propose method utilizes a localised Bayesian regularised neural network model (BRNNM) to obtain the energy concentration along the instantaneous frequencies (IFs) of individual components in the multicomponent signals without assuming any prior knowledge. The spectrogram and pre–processed Wigner–Ville distribution (WD) of the signals with known IF laws are used as the train- ing set for the BRNNM. These distributions, taken as two–dimensional (2–D) image matrices, are vectorized and clustered according to the elbow criterion. Each cluster contains the pairs of the input and target vectors from the spectrograms and highly concentrated pre–processed WD respectively. For each cluster, the pairs of vectors are used to train the multiple ANNs under the Bayesian framework of David Mackay. The best trained network for each cluster is selected based on network error criterion. In the test phase, the test TFDs of unknown signals, after vectorization and clustering, are processed through these specialized ANNs. After post–processing, the resultingTFDs are found to exhibit improved resolution and concentration along the individual components then the initial blurred estimates. The third part presents the discussion on the experimental results obtained by the proposed technique. Moreover the framework is extended to include the various objec- tive methods of assessment to evaluate the performance of de–blurred TFDs obtained through the proposed technique. The selected methods not only allow quantifying the quality of TFDs instead of relying solely on visual inspection of their plots, but also help in drawing comparison of the proposed technique with the other existing tech- niques found in literature for the purpose. In particular the computation regularities show the effectiveness of the objective criteria in quantifying the TFDs'' concentration and resolution information.
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شہرِ نبیؐ میں مکہ سے ہو کر چلیں گے ہم


شہرِ نبیؐ میں مکّہ سے ہو کر چلیں گے ہم
دامانِ داغدار کو دھو کر چلیں گے ہم

تر دامنی کو اشکِ ندامت سے دھوئیں گے
عشقِ نبیؐ میں خود کو ڈبو کر چلیں گے ہم

روئیں گے خوب شہرِ مدینہ کی یاد میں
اشکوں کے خوب ہار پرو کر چلیں گے ہم

روح و دل و دماغ میں طیبہ کی ہو فضا
یوں صحنِ جاں میں شوق کو بو کر چلیں گے ہم

’’ماذاغ‘‘ کی ادا کا تکلّم کلیمؑ سے
تم کام کر نہ پائے تھے جو ؛ کر چلیں گے ہم

آغوش میں یوں نیند نے لے کر مجھے کہا
آؤ درِ رسولؐ پہ سو کر چلیں گے ہم

عرفانؔ ! اب تو عزم یہی چشمِ تر کا ہے
داغِ غمِ فراق کو دھو کر چلیں گے ہم

أدب الرحلة: أهميته وأسلوبه وخصائصه وتطوره

Travelogue is a firm of literature which describes nation and people according to their history, civilization, politics, economics, and culture and presents cities and culture by showing the ideologies and manners/moralities, economics and society in the time when there were no transportation and the travelogues were the only source to get information. Because travelogue consists of the details about history and society, thus it has a tremendous amount of information and by offering characteristics of places and personalities. Moreover, travelogue describe personalities and events in the context of society and culture which provides a rich material to geologists, historicists as well as to the scholars of society ( sociologists) and students of literature and others.

Application of Fuzzy Ontology in Image Retrieval

Rapid increase in the use of digital images either for security, health treatment, or entertainment demands an effective image retrieval system. In text based image retrieval, images are annotated with keywords based on human perception. A user query is composed of keywords according to his/her requirements. Query keywords are matched with the keywords associated with images, for retrieval. This process has been extended with ontology to resolve semantic heterogeneities in keywords matching. However, crisp annotation and retrieval processes could not produce the desired results because both processes involve human perception. To reduce the matching complexities produced due to human perception, an image retrieval model has been proposed in this thesis that makes use of fuzzy ontology for improving retrieval performance. For representing the image content, it is divided into regions in our dataset and then regions are classified into concepts. The concepts are combined into categories. The concepts, categories and images are linked among themselves with fuzzy values in ontology. The model has been evaluated through both objective and subjective measures. Experimental results show that the proposed system performs better than the existing systems in terms of retrieval performance. Besides this, users usually desire higher proportion of the query keywords in the retrieved images than other undesired keywords. Existing systems return images that mostly do not contain the query keywords either in equal or higher proportion than other keywords. The research in this thesis resolves this issue by applying uncertain frequent pattern mining on the association that exists among the concepts in images. These patterns assist in retrieving images that contain the required query keywords in high proportion. The ranking of retrieved images has been objectively evaluated using two different measures. Experimental results show that the proposed image retrieval system performs better than existing image retrieval systems. The results of image retrieval systems are typically assessed for quality either by objective or subjective evaluation measures. These measures usually produce good results in typical image collections with predefined categories. However, the results of objective evaluation measures deteriorate in collections where an individual image may belong to multiple categories. Furthermore, conducting subjective evaluation is very difficult if not impossible on a large number of queries for every collection due to humans’ involvement, as it is a tedious and time consuming task. Therefore, an automated assessment model for subjective evaluation in image retrieval systems is required. The main hurdle in creating such an automated system is the availability of subjective evaluation benchmark for the retrieved images. This thesis also presents a new benchmark and a novel evaluation model for conducting automated subjective evaluation by tackling it as a supervised machine learning problem with support vector regression (SVR). The experimental results demonstrate that the proposed system automatically predicts the mean opinion score (MOS) with reduced error and correlates well with human subjects’ assessment.