Singular Value Decomposition of Wigner Distribution for Time-Frequency Representation of Ultrasonic Echoes

Wigner distribution (WD) is an effective tool for characterizing non-stationary signals where different frequency components arrive at different times. WD was proposed in 1932 by Wigner with applications in quantum mechanics [1]. WD offers high frequency resolution, and satisfies important properties such as marginals and time/frequency shifts. However, in spite of these advantages, WD creates spurious frequency information (cross-terms) when it is applied to signals consisting of multiple echoes or to a signal corrupted by noise. The cross-terms interfere with and often mask the true time-frequency information associated with echoes of interest. Due to the random and complex nature of backscattered ultrasonic echoes, and because the echoes are not exactly Gaussian in shape, the WD of ultrasonic signals is corrupted by the cross-terms. In this paper, singular value decomposition (SVD) is used to analyze and reduce the cross-terms

An issue-based approach to organisational legitimacy: the case of Namdeb

In this investigative study an issue-based approach is employed to examine the effects of a continuous flux of everyday, dynamic and often interconnected or interrelated political, economic, social, environmental and legislative issues involving mostly external stakeholders. The case study method was used and the issues influencing the legitimacy of Namdeb, a public private joint venture (PPJV) between the Government of Namibia and De Beers, international diamond miner and retailer was investigated. The findings show that a number of interconnected and constant issues collectively influence organisational legitimacy on a daily and continuous basis. Furthermore, most of these issues are moral issues. Moreover, political issues were specifically identified as a major source of adverse impact on organisational legitimacy. On both the theoretical and practical levels, the need for a tool to help with the identification, classification and management of the issues affecting organisational legitimacy was also recognised. To assist with this, a two- dimensional alternative to Suchman's (1995) typology of organisational legitimacy which is considered the reference in the field of legitimacy theory, was developed by taking into consideration issue and legitimacy types. The study was conducted for two main reasons. Firstly, no existing study concentrating on the various collective and everyday issues affecting organisational legitimacy has thus far been embarked upon. Secondly, no empirical evidence based on the direct input, or more precisely points of view of external stakeholders, has been identified in the current literature and yet organisational legitimacy is said to be dependent on some degree of shared agreement among societal constituencies or stakeholders that an organisation is aligned with accepted notions of purpose, endeavor and outcomes

’n Funksionele benaderingswyse by godsdiensonderrig

Helmut Thielicke het êrens opgemerk: “If Protestantism ever dies with a dagger in the back the dagger will be the Protestant sermon”. Met hierdie stelling beklemtoon Thielicke die verband tussen die verlies aan bindingskrag by die Protestantse Christendom in sy tradisionele vorme en die gehalte of kwaliteit van die Woordverkondiging. Kundiges is van mening dat daar by die Woordverkondiging gewerk word met uitgediende en ondoeltreffende godsdienstige denk- en aktiwiteitsvorme. In teologiese kringe word die hermeneutiek en prediking onder die soeklig gestel. Hoe die predikant die stem van God hoor en hoe hy dit aan die moderne mens deurgee, het vir die teologie ’n probleemgebied geword

Hearing loss amongst dr-tb patients that received extended high frequency pure tone audiometry monitoring (kuduwave) at three dr-tb decentralized sites in Kwazulu-Natal

Doctor EducationisOtotoxic induced hearing loss is a common adverse event related to aminoglycosides used in Multi Drug Resistant -Tuberculosis treatment. Exposure to ototoxic drugs damages the structures of the inner ear. Symptomatic hearing loss presents as tinnitus, decreased hearing, a blocked sensation, difficulty understanding speech, and perception of fluctuating hearing, dizziness and hyperacusis/recruitment. The World Health Organization (1995) indicated that most cases of ototoxic hearing loss globally could be attributed to treatment with aminoglycosides. The aim of the study was to determine the proportion of DR-TB patients initiated on treatment at three decentralized sites during a defined period (1st October to 31st December 2015) who developed ototoxic induced hearing loss and the corresponding risk factors, whilst receiving audiological monitoring with an extended high frequency audiometer (KUDUwave). A retrospective cross-sectional study was conducted. Cumulatively across the three decentralized sites, 69 patient records were reviewed that met the inclusion criteria of the study. The mean age of the patients was 36.1, with a standard deviation (SD) of 10.7 years; more than half (37) were female. Ototoxicity , a threshold shift, placing patients at risk of developing a hearing loss was detected in 56.5% (n=39)of patients and not detected in 30.4%(n=21).The remaining 13,1% (n=9)is missing data. As a result, the regimen was adjusted in 36.2% of patients. . From the 53 patients who were tested for hearing loss post completion of the injectable phase of treatment, 22.6% (n=12) had normal hearing, 17.0 % (n=9) had unilateral hearing loss, and 60.4% (n=32) had bilateral hearing loss. Therefore, a total of 41 patients had a degree of hearing loss: over 30% (n=22)had mild to moderate hearing loss, and only about 15% (n=11)had severe to profound hearing loss. Analysis of risk factors showed that having ototoxicity detected and not adjusting regimen significantly increases the risk of patients developing a hearing loss. The key findings of the study have shown that a significant proportion of DR-TB patients receiving an aminoglycoside based regimen are at risk of developing ototoxic induced hearing loss, despite receiving audiological monitoring with an extended high frequency audiometer that allows for early detection of ototoxicity (threshold shift)

Discounting of quantity surveying fees in South Africa

The discounting of professional fees has become a cause for concern among South African Quantity Surveying practitioners. These discounts are often 30% to 40% and, in some cases, substantially below the Tariff of Professional Fees published by the South African Council for the Quantity Surveying Profession (SACQSP). The firms which offer these excessively high discounts may be pricing their services well below their in-house operational costs which, with the quality of their professional services, eventually become unsustainable. A quantitative approach was used to conduct a research study to determine the effect of discounting of fees on the Quantity Surveying profession. The data was obtained by circulating a structured web-based questionnaire to registered professional Quantity Surveying firms in all nine provinces in South Africa. Results indicated that when Quantity Surveyors discount their fees, this impacts negatively on the quality of their professional services. Respondents further recommended that there should be some form of regulation regarding the discounting of fees, while others suggested that the current SACQSP recommended fee scale be replaced by the re-introduction of a statutory minimum fee scale which was applied prior to 1988. The findings arising from this research could support potential efforts by the SACQSP to resolve issues regarding this practice and serve to raise awareness among Quantity Surveying practitioners of the dangers inherent in, and resulting negative consequences of discounting their fees

Modeling No-Till Adoption by Corn and Soybean Producers: Insights Into Sustained Adoption

No-till acreage has increased in recent years, but many farmers alternate no-till with other tillage practices, limiting public and private benefits from sustained no-till adoption. Revealed preference data are used in an ordered logit regression analysis to determine the effect of soil characteristics, climate, regions, farm characteristics, and producer demographics on producers’ choices to use continuous tillage, alternate no-till systems with tillage systems, or continuously use no-till. The model provides insight into the characteristics and conditions that are conducive to each tillage regime. The attributes found to significantly affect continuous no-till use are erodibility classification, drainage, farm size, and climat

On positivity of time-frequency distributions.

Consideration is given to the problem of how to regard the fundamental impossibility with time-frequency energy distributions of Cohen's class always to be nonnegative and, at the same time, to have correct marginal distributions. It is shown that the Wigner distribution is the only member of a large class of bilinear time-frequency distributions that becomes nonnegative after smoothing in the time-frequency plane by means of Gaussian weight functions with BT product equal to unity