Energy-efficient spectrum sensing approaches for cognitive radio systems

Designing an energy efficient cooperative spectrum sensing for cognitive radio network is our main research objective in this dissertation. Two different approaches are employed to achieve the goal, clustering and minimizing the number of participating cognitive radio users in the cooperative process. First, using clustering technique, a multilevel hierarchical cluster-based structure spectrum sensing algorithm has been proposed to tackle the balance between cooperation gain and cost by combining two different fusion rules and exploiting the tree structure of the cluster. The algorithm considerably minimizes the reporting overhead while satisfying the detection requirements. Second, based on reducing the number of participating cognitive radio users, primary user protection is considered to develop an energy efficient algorithm for cluster-based cooperative spectrum sensing system. An iterative algorithm with low complexity has been proposed to design energy efficient spectrum sensing for cluster-based cooperative systems. Simulation results show that the proposed algorithm can significantly minimize the number of contributing of cognitive radio users in the collaboration process and can compromise the performance gain and the incurred overhead. Moreover, a variable sensing window size is also considered to propose three novel strategies for energy efficient centralized cooperative spectrum sensing system using the three hard decision fusion rules. The results show that strategies remarkably increase the energy efficiency of the cooperative system; furthermore, it is shown optimality of k out of N rule over other two hard decision fusion rules. Finally, joint optimization of transmission power and sensing time for a single cognitive radio is considered. An iterative algorithm with low computational requirements has been proposed to jointly optimize power and sensing time to maximize the energy efficiency metric. Computer results have shown that the proposed algorithm outperforms those existing works in the literature

Case study of TV spectrum sensing model based on machine learning techniques

Spectrum sensing is an essential component in cognitive radios (CR). Machine learning (ML) algorithms are powerful techniques for designing a promising spectrum sensing model. In this work, the supervised ML algorithms, support vector machine (SVM), k-nearest neighbor (kNN), and decision tree (DT) are applied to detect the existence of primary users (PU) over the TV band. Moreover, the Principal Component Analysis (PCA) is incorporated to speed up the learning of the classifiers. Furthermore, the ensemble classification-based approach is employed to enhance the classifier predictivity and performance. Simulation results have shown that the highest performance is achieved by the ensemble classifier. Moreover, simulation results have shown that employing PCA reduces the duration of training while maintaining the performance

Autopolypectomy of a Vocal Cord Polyp

Introduction Vocal cord polyps commonly occur in those with a history of vocal abuse. Patients with large lesions generally undergo microlaryngeal surgery under general anaesthesia. This unique case report highlights a strange scenario where the patient coughed out a fleshy mass during his morning walk and which was later confirmed as a vocal cord polyp.  Case Report A 62 year old male with a history of hoarseness of voice for 3 months presented to the ENT OPD holding a chunk of tissue which was apparently coughed out by him during his morning walk. After the incident, his symptoms had immediately improved. A videolaryngoscopy showed a congested spot on the right vocal cord being the probable site of origin of the lesion. On Histopathological examination, the tissue was reported as a vocal cord polyp.  The patient was managed conservatively but the lesion recurred at the same site after a month for which a microlaryngeal excision was performed. Discussion Vocal cord polyps are fairly common in ENT practice and usually present to the clinic with hoarseness of voice. Polyps that are small are usually managed conservatively by voice therapy alone whereas large polyps require surgical excision. This unique case report highlights a strange clinical scenario where the patient coughed out a large vocal cord polyp (Auto-polypectomy) during a bout of acute cough. This event saved him a surgery at the first instance, but eventually had a recurrence and had to undergo an excision under GA

Ibn Khalduns Approach to the Science of Knowledge an In- Depth Study on the Reception and Critique of News

The research studies the science of know-how and its rooting in Ibn Khaldun, after presenting some historical applied examples and scientific indications of some scholars. With its harmony with the approach of innate human reception, and the nature of its communication is special, including intellectual and experiential, which includes right and wrong, or truth and lies. The research presented the definition of the term from the linguistic and terminological point of view, in addition to attributing its status to Ibn Khaldun, and presents the standards that Ibn Khaldun defined. To be relied upon in accepting and rejecting news, as well as the qualities that must be available for those who work in the sciences of history in particular, and the rest of knowledge in general. The research concluded that this section was subjective, impressionistic, and scattered in the human experience. After Ibn Khalduns accession to it, it became closer to objectivity than to subjectivity. This achievement attributed to Ibn Khaldun is an achievement added to his repeated creations in the humanities, especially sociology

The Quranic Readings and the Impact of Syntactic and lexical Differences on their Semantic Integration, Verses from Surah Al- Baqarah

This research focuses on the various Quranic readings of verses from Surah Al-Baqarah. The study reveals that these readings complement each other in their different linguistic expressions, in terms of their variations in morphological and lexical aspects. The study affirms that this variation does not lead to contradiction; rather, it represents a harmonious portrayal and depiction of meaning. This is done in order for the message or purpose of the speech to reach the recipient, whether they are a reader or a listener, in the most comprehensive manner possible, encompassing all possible rational aspects within the context, words, and structures

Autopolypectomy of a Vocal Cord Polyp

Introduction Vocal cord polyps commonly occur in those with a history of vocal abuse. Patients with large lesions generally undergo microlaryngeal surgery under general anaesthesia. This unique case report highlights a strange scenario where the patient coughed out a fleshy mass during his morning walk and which was later confirmed as a vocal cord polyp.  Case Report A 62 year old male with a history of hoarseness of voice for 3 months presented to the ENT OPD holding a chunk of tissue which was apparently coughed out by him during his morning walk. After the incident, his symptoms had immediately improved. A videolaryngoscopy showed a congested spot on the right vocal cord being the probable site of origin of the lesion. On Histopathological examination, the tissue was reported as a vocal cord polyp.  The patient was managed conservatively but the lesion recurred at the same site after a month for which a microlaryngeal excision was performed. Discussion Vocal cord polyps are fairly common in ENT practice and usually present to the clinic with hoarseness of voice. Polyps that are small are usually managed conservatively by voice therapy alone whereas large polyps require surgical excision. This unique case report highlights a strange clinical scenario where the patient coughed out a large vocal cord polyp (Auto-polypectomy) during a bout of acute cough. This event saved him a surgery at the first instance, but eventually had a recurrence and had to undergo an excision under GA

Self-reported depression and anxiety rates among females with cutaneous leishmaniasis in Hubuna, Saudi Arabia

Background Cutaneous leishmaniasis (CL) is a parasitic disease transmitted through the bite of infected sandflies, causing disfiguring skin lesions and a range of physical symptoms. However, the psychological impact of CL is often overlooked despite the significant burden it imposes on the affected individuals and communities. This is especially true in Saudi Arabia, where limited research exists on the psychological consequences of CL, particularly among females. This study aimed to address this knowledge gap by investigating the perceived psychological problems associated with CL among females living in the Hubuna area of Saudi Arabia. Methods This cross-sectional study recruited 213 females with CL in the Hubuna area of Saudi Arabia using purposive sampling. Data was collected using a self-administered electronic questionnaire that included socio-demographic characteristics and measures of depression and anxiety using the BDI and GAD-7 tools. Descriptive analysis was used to determine the psychological impact of CL, including means and standard deviations for the BDI and GAD-7 scores, as well as frequencies and percentages for other variables of interest. Logistic regression was performed to identify independent predictors of anxiety and depression, including variables such as age, marital status, education, occupation, number and location of lesions. The significance level for all statistical tests was set at p < 0.05. The study was carried out between September and December of 2022. Results The study found that the mean Beck Depression Inventory (BDI) and Generalized Anxiety Disorder-7 (GAD-7) scores among the participants were 8.67 ± 4.82 out of 63 and 8.20 ± 7.08 out of 21, respectively. Furthermore, the prevalence of depression and anxiety was 55.9% and 68.1%, respectively, indicating a significant psychological burden associated with CL in the study population. The results of the logistic regression analysis showed that anxiety and depression were significantly associated with age, marital status, number of lesions, and location of the lesions on the body, highlighting the importance of considering these factors when designing interventions aimed at improving the mental health of CL patients. Conclusions In conclusion, this study highlights the significant psychological impact of CL among females in the Hubuna area of Saudi Arabia, calling for urgent action to address this neglected aspect of the disease. By integrating mental health considerations into CL prevention and management efforts, healthcare providers can improve the overall well-being of affected individuals and contribute to the broader goal of eliminating CL as a public health concern

Iterative illumination correction with implicit regularization

This paper presents a retrospective algorithm for correcting the uneven illumination field in microscopy images. The illumination field is iteratively made uniform using an increasing sequence of bivariate polynomials. At each iteration, the least squares problem of fitting a 2-D polynomial to a sampled image is solved by using QR decomposition with column pivoting, where image samples are obtained by dynamic programming or watershed transform. This incremental scheme allows the smoothness constraint of the estimated bias field to be implicitly satisfied. The proper number of iterations is determined by an automatic stopping criterion. The experimental results show the effectiveness of the proposed approach when compared to a set of different well-established methods

Thermal degradation of cellulose and cellulosic substrates

This chapter is aimed to thoroughly describe the thermal degradation of cellulose and cellulosic substrates (like cotton and paper), investigating the involved reaction mechanisms. After a brief introduction about the real reasons that motivated the study on cellulose degradation, a first general introduction on cellulose thermal degradation (namely, pyrolysis) and thermooxidation will be presented, followed by a detailed description of the related mechanisms with particular attention to the main degradation products consisting of volatile species and char (carbonaceous residue). To this aim, some of the most important factors affecting the volatilisation and charring balance (i.e. heating rate, presence of humidity, metals and flame retardants) are considered and thoroughly discussed in order to provide a complete scenario about the cellulose degradation phenomeno