Computers Modulator Demodulators (Modems) are used to change the analogue :: Computer Science

Computers Modulator Demodulators (Modems) are used to change the analogue to digital and the other way around Analogue to Digital Conversion Matt Davey Analogue to Digital Conversion is the way of converting a continous analogue signal to a series of digital binary numbers. This is done in many pieces of hardware by taking samples of the analogue signal and then each sample is digitised into a binary code by a microchip. This process is known as Quantization a process where a continuous signal is converted to a series of points at discrete levels. This process is specific to the music industry. In Computers Modulator Demodulators (Modems) are used to change the analogue to digital and the other way around. The modem uploads data to the Internet by converting it to an analogue signal and broadcasting it through the phone line, then when downloading it converts the analogue signal to binary 1’s and 0’s. The analogue wave is created by vibrations in the sound the waveform today is usually recorded into digital format by an Analogue Digital Converter (ADC). The Waveform is turned into a stream of numbers and the ADC records the numbers and feeds them through the speakers. In the computer world a modem is commonly used to connect to the largest Wide area network the internet. The modem uses ASCII Code to translate the waveform to the computer and then back to waveform to translate it and broadcast it over the phone line again. This was thought to be irreverent when ISDN came in because ISDN was a digital network but this didn’t take off because of the price and the work involved in setting one up but speeds of an ISDN reached 128kbps this was fast for the time. All ADCs work by sampling their input at intervals of time.

Expected Shortfall Essay

Part I describes the calculation ofVaR in its conventional form. For illustrative purposes, Part I will describe parametric VaR on a Gaussian distribution. Part II summarizes known weaknesses in VaR, from inherent model and estimation risk to VaR’s failure to perform under extreme economic stress and VaR’s failure to satisfy the theoretical constraints on â€Å"coherent† measurements of risk. Part Ill describes how to calculate expected shortfall as an extension of conditional VaR. It further describes how expected shortfall, but not VaR, provides a coherent measure of risk. Part Ill then reverses field. It explains how VaR, but not expected shortfall (or, for that matter, nearly every other general spectral measure of risk), satisfies the mathematical requirement of â€Å"elicitability. † Mathematical limitations on measures of risk therefore force regulators and bankers to choose between coherence and elicitability, between theoretically sound consolidation of diverse risks (on one hand) and reliable backtesting of risk forecasts against historical observations. Justin Smith Morrill Professor of Law, Michigan State University (effective July 1, 2013). This paper summarizes a presentation made on April 17, 2013, at Georgetown Law Center’s colloquium on international financial regulation, conducted by Professor Christopher J. drummer. I appreciate comments by Adam Candeub and Jeffrey Sexton. Special thanks to Heather Elaine Worland Chen. Jim Chen Page 1 Electronic copy available Conventional VaR Like modern portfolio theory and the entire edifice of quantitative finance derived from those beginnings,l conventional value-at-risk analysis assumes that risk is rguably represents the most important tool for evaluating market risk as one of several threats to the global financial system. Basel II identifies a version ofVaR analysis as that accord’s preferred tool for assessing banks’ exposure to market risk. 4 Authorities around the world have endorsed VaR, either as a regulator standard or as a best practice. Even absent regulatory compulsion, private firms routinely use VaR as an internal risk management tool, often directing traders to reduce exposure below the level prescribed by those firms’ own VaR limits.

Measuring Wind Speed in Knots

In meteorology (and in sea and air navigation as well), a  knot is a unit of speed  typically used to indicate  wind speed. Mathematically, one knot is equal to about 1.15 statute miles. The abbreviation for a knot is kt or kts if plural. Why Knot Miles per Hour?   As a general rule in the US, wind speeds over land are expressed in miles per hour, while those over water are expressed in knots (largely because knots were invented over a water surface).  Since meteorologists deal with winds over both surfaces, they adopted knots for the  for the sake of consistency. However, when passing along wind information to public forecasts, knots are typically converted into miles per hour for the publics ease of understanding.    Why Is Speed at Sea Measured in Knots? The reason why sea winds are measured in knots at all has to do with maritime  tradition.  In centuries past, sailors didnt have GPS or even speedometers to know how fast they were traveling across the open sea. So to estimate their vessels speed,  they crafted  a tool made up of a  rope several  nautical miles in length with knots tied at intervals along it and a piece of wood tied at one end. As the ship sailed along, the wood  end of the rope was dropped  into the ocean and remained roughly in place as the ship sailed away. The number of knots was counted as they  slipped off of the ship  out to sea over  30 seconds (timed using a glass timer). By counting the number of knots that unspooled within that 30-second period, the ships speed could be estimated.   This not only tells us where the term knot comes from but also how the knot relates to a nautical mile: it turned out that the distance between each rope knot equaled one nautical mile. (This is why 1  knot is equal to 1 nautical mile per hour, today.)   Unit of Measure Surface winds mph Tornadoes mph Hurricanes kts (mph in public forecasts) Station Plots (on weather maps) kts Marine forecasts kts Units of Wind for Various Weather Events & Forecast Products Converting Knots to MPH Because being able to convert knots to miles per hour (and vice versa) is a must. When converting between the two, keep in mind that a knot will look like a lower numerical wind speed  than a mile per hour.  (One trick to remembering this is to think of the letter m in miles per hour as standing for more.) Formula to convert knots to mph:#  kts * 1.15   miles per hour Formula to convert mph to knots:#  mph * 0.87   knots Since the SI unit of speed happens to be  meters per second (m/s), it might also be helpful to know  how to convert wind speeds to these units. Formula to convert knots  to m/s:#  kts  * 0.51   meters per second Formula to convert mph to m/s:#  mph * 0.45   meters per second If you dont feel like completing the math for the conversion of knots to miles per hour (mph) or kilometers per hour (kph), you can always use a free online wind speed calculator to convert the results.