RE-WRITE Essay Example | Topics and Well Written Essays - 1500 words

RE-WRITE - Essay Example The usual assumption is that ambient noise is isotropic (equal on all directions). This is commonly considered in sonar equations. We therefore attempt to reduce the effective noise level by utilising of the directional capabilities of the hydrophone (NL-DI). However, in deep waters the sea surface is considerably the principal source of ambient noise. It these areas the ambient level is not truly isotropic. Conversely, in shallow waters ambient noise is essentially isotropic due to reflections from the sea floor (Davidson, 2006). The features of the parametric approach are best illustrated on an example taken from a hypothetical sonar application. The approach was to apply time-frequency circumstances for detection. The detection conditions are simply: The second level, in particular, enables signal detection of a very low false alarm rate on narrow-band sonar signals. It acts as a narrow band pass filter at the input of detection algorithm, which efficiently eliminates out-of-band noise. Figure 1 shows a 50 kHz sonar return from shallow water. Simulated water-depth is 3 m. the transmit pulse has a duration of 0.4 Ms. The noise is of uniform distribution restricted to the signal band. Signal to noise ratio (S/N) is 20 dB while the signal’s full waveform was digitised at the rate of 1 MHz. Only the envelope of the signal is shown in Figure 1. Without any further processing, the echo time series, which consists of 1000 sample, is now submitted to the detection algorithm. While the parametric model is calculated for every sample, the spectrum from 48 kHz to 52 kHz is computed for every 10th interval. The 4 kHz band is evaluated at 200 frequencies with a resolution of 20 Hz. A three dimensional view of the sonogram (Figure 2) may illustrate how well the spectral peaks in the sonar return are defined in a time-frequency representation. The algorithm is very fast and real time processing capable. It does not require that the

Profession Of Freelance Writer And Its Perspectives Essay

Profession Of Freelance Writer And Its Perspectives - Essay Example After a few email queries back and forth, I was able to conduct an interview with Ms. Strain via Skype. What she had to say about being a freelance writer completely changed my attitude about what writing is and its usefulness in the real world of business. "Being a freelance writer isn't at all like being the starving artist in the Garrett," Ms. Strain said when I mentioned my impressions to her. She was laughing, so I didn't worry that Id offended her. In fact, her easy-going attitude made it very easy to ask questions I might not have asked someone who was more uptight. After we got done laughing, Ms. Strain explained that freelance writers are master jugglers who must change costumes, objects and the numbers of objects flying at a moments notice. Instead of just sitting around dreaming up the next Great American novel, she explained that freelance writers like herself are usually kept very busy by the corporate world writing things like white papers, promotional video scripts, product descriptions, sales materials, technical manuals, case studies, web pages and internal business-related documents like business plans and project proposals. Ms. Strain also writes creatively, though, so she offers other writers services like ghostwriti ng, editing, reviews, and proofreading. The types of written materials she produces can be very different from one assignment to the next not just because the type of document shes writing is different, but also because the audience or the purpose might be different which means the tone of voice and types of proof she needs to use will change. When I asked Ms. Strain who she wrote for, her quickest answer was to say "anyone who will pay me!" But then she went on to explain that most of her clients were businesses or government and most of the work they send her way is related to the natural flow of business.