# What is Reduction: Definition and 468 Discussions

Noise reduction is the process of removing noise from a signal. Noise reduction techniques exist for audio and images. Noise reduction algorithms may distort the signal to some degree.
All signal processing devices, both analog and digital, have traits that make them susceptible to noise. Noise can be random or white noise with an even frequency distribution, or frequency-dependent noise introduced by a device's mechanism or signal processing algorithms.
In electronic recording devices, a major type of noise is hiss created by random electron motion due to thermal agitation at all temperatures above absolute zero. These agitated electrons rapidly add and subtract from the voltage of the output signal and thus create detectable noise.
In the case of photographic film and magnetic tape, noise (both visible and audible) is introduced due to the grain structure of the medium. In photographic film, the size of the grains in the film determines the film's sensitivity, more sensitive film having larger sized grains. In magnetic tape, the larger the grains of the magnetic particles (usually ferric oxide or magnetite), the more prone the medium is to noise. To compensate for this, larger areas of film or magnetic tape may be used to lower the noise to an acceptable level.

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1. ### B TV Series: 3 Body Problem - affects gravitational force?

SPOILERS This obviously wouldn't happen to that extent, not without tearing the planet to pieces as well. But might they feel a reduction in weight at all? Obviously it's a pretty hypothetical question without any specifics about the distances to the suns but in theory at least.

3. ### Inflection Point Calculation: Reduction of Cubic with Second Derivative Method

(i) I take the second derivative of Y: Y'' = 6X + 2A. Y'' = 0 when X = -A/3. Moreover, as Y'' is linear it changes sign at this X. Thus, it is the point of inflection. (iii) After the substitution, the term x^2 appears twice: one, from X^3 as -3(x^2)(A/3), and another from AX^2 as Ax^2. They...
4. ### Impact force reduction after passing through a medium

Hello, Please see the attached sketch. A car hits a mass of soil and applies the impact force of F. The force/wave travels the distance L through the mass at the end of which there is a wall so I think the force attenuates. Assume we have all the properties of the mass. My question is, what...
5. ### B Row reduction, Gaussian Elimination on augmented matrix

Hi! Please, could you help me on how to solve the following matrix ? I need to replace the value 3 on the third line by 0, the first column need to remain zero and 1 for the third column. I'm having a lot of difficulties with this. How would you proceed ? Thank you for your time and help...
6. ### A Thermodynamics Derivative Reduction Problems

Hi everyone, I'm in a graduate level mechanical engineering thermodynamics class. We're working on derivative reductions using the gibbs and maxwell relations. I was wondering if anyone has any good sources of practice problems that I could use. I've looked through my textbook and there are...
7. ### I Diophantine approximation via Lattice Reduction

With some help from another thread, I learned how to solve a simultaneous diophantine approximation involving log(2), log(3), log(5) etc. This method is based on Mathematica's LatticeReduce function. At first, I was quite happy to use it as a black box to work on some hobby math exploration, but...

9. ### About oxidation and reduction in organic Chemistry

We studied in chemistry that the concept of oxidation and reduction is the exchange of electrons between two chemical substance ,but when i started to study organic chemistry i saw that when we talk about for example the oxidation of a compound it can loss atoms and change his constitution...
10. ### Chemistry Solving H2/Pd/C Reduction for #5 & #6 Questions

Hi, I'm trying to solve the number 5 and 6. Now I'm wondering what happens when I add H2/Pd/C on the 4th (after the question 4) molecule. I know that it will reduce pi bonds to sigma bonds, but will it affect the cetal group? Because if it does't I'm not quite sure that I'll be able to do the...
11. ### Chemistry Reduction of ester and amide with LiAlH4

Hi, I am trying to solve number 8. At 7, I have a molecule that contains both an amide and ester function. So when I use LiAlH4, will I reduce both the ester to alcohol and the amide to secondary amine? Or just the ester? Thank you so much for your help!
12. ### How to make an audio processing device for noise reduction ?

Hello everyone !I am working on noise reduction and I wanted to do some experiments with an arduino. I took an arduino which get music (as an example) in input by jack. It also has a microphone and in a first try the goal is to get as an output the music - the noise around... To act like a kind...

14. ### Reduction of Order Problem for Differential Equations Class

Problem statement: Second order linear differential equation in standard from Reasoning:
15. ### What % reduction in gas flow results from changing to LPG?

There are 70 jets of 1/16" diameter along the tube and I neeed to create flames 1" high. I know the calorific value of natural gas is much less than LPG (39 MJ/m3 Vs 93 MJ/m3) . I am not sure what assumptions to make from there in order to compare the predicted natural gas to the LPG volume...
16. ### Measuring ripple reduction in LTSpice

Dear friends, I am simulating a capacitance multiplier circuit and an RC filter circuit simultaneously. My aim is to check the reduction in ripples when using a cap multiplier circuit against an RC filter. I am familiar with ltspice but not quite an expert. I am comparing two output waveforms...
17. ### Formula for ionization potential reduction

Hello, Firstly I am not sure of understanding the problem, I believe that this reduction is related to a high density plasma where the free electrons are very close to the ions and so the ions cannot be considered as separate bodies... I also believe it affects the ground energy state of...
18. ### 3D Printer Stepper Motor Torque Requirements Using Gear Reduction

I hope to explore mechanical engineering one day so I can answer these kinds of questions on my own, but until then, I appeal to anyone that knows how to do this to help me. I am building a core xy 3D Printer and I want to use a belt driven Z axis. I will have 3 or 4 stepper motors to drive...
19. ### MHB 307.1.1 Use row reduction on the appropriate augmented

$\tiny{307.1.1}$ Use row reduction on the appropriate augmented matrix to solve the following system of equations: $\begin{array}{ll}3x+2y&=2\\x-y&=1\end{array} \sim\left[\begin{array}{rr|r}3&2&2\\ \:1&-1&1\end{array}\right]\sim \begin{bmatrix}1&0&\frac{4}{5}\\ 0&1&-\frac{1}{5}\end{bmatrix}$...
20. ### Compression ratio and volume reduction of CO2

The question is: If the compression ratio of car engines is increased by 10% (from 10 to 11), estimate the volume reduction in annual CO2 emission. Assume there are 30 million cars each consuming one cubic meter of fuel annually. The question is looking for a rough estimate for an answer. I...
21. ### B What is the entire gear reduction ratio of a vehicle?

As I was looking in the caracteristics of an old tank, I found a number that I could not get anything of on the web. It is called "entire reduction ratio" and was presented just under the gearbox caracteristics. His value is 1:13.4. My question is : is it useful? Does this value have relation...

23. ### Chemistry Thermodynamics: Reduction Potential question

The answer key says the correct option should be a, but I think it should be b. Because Y has a reduction potential same as the element B. An element is a good reducing agent only if its reduction potential is negative or less positive.
24. ### Lawn/Garden Improving noise reduction for ear muffs

The lining on my ear muffs which contact the ears, developed cracks and eventually split apart. I decided to try and repair the muffs, so they would have noise reducing qualties than those were better than any typical store bought muffs. Unfortunately, the finished product, reduced the outside...

26. ### What does "....10000 units per 15 min (quick reduction)" mean?

Hello, looking to find out what the term "10000 units per 15 min (quick reduction)" from the WHO means in terms of using heat to kill a virus.
27. ### Realistic Core Weight Reduction for 1000Hz Freq in 100KW DC/DC Converter

I have a customer looking for a 100KW isolated DC/DC converter. What is a realistic transformer core weight reduction if we get 1000Hz fundamental. Assume a 60Hz core is 300 Lbs, how much smaller could a 1kHz Core be?
28. ### CO2 reduction driven by a pH gradient

In the world of Origin of Life hypothesizing, there now seem to be two main competing approaches. Life originating at alkaline hydrothermal vents and an origin in intermittent terrestrial pools (exposed to periods of drying) getting outflow from volcanically heated water sources. The alkaline...
29. ### DFA Minimization Marking Step Guide | Zulfi

mod note: not homework I have got a DFA. I can't understand the marking procedure used for DFA minimizationHi, I am not able to understand the marking step for DFA minization. Some body please guide me. I have uploaded the image. Zulfi.
30. ### Question on the reduction of FeO by CO

Some numbers below: these are the standard molar enthalpies and entropies at 298K that I got from a website. In the reaction FeO + CO = Fe + CO2, the deltas are: delta H = (0+ -393) - (-266.5+ -110.5) = -16.3 KJ/mol. delta S = (27.2+213.8) - (197.9+54) = -10.9 J/mol/K Now at 1200 K, Go = -16.3 +...
31. ### Why does the apparent weight decrease when a body accelerates down a rope?

When a body accelerates down(climbs down) a rope, why does its apparent weight reduce? Oh wait, does it even reduce in the first case? If yes, is it because of the Newtons first law of motion, which states that a body in motion tends to be in motion and a body at rest tends to be at rest. So...
32. ### Calculate the reduction in the deflection at the free end

I can solve the deflection if only cantilever beam by deflection formula, but i have no idea for this question if calculated with a cable support arrangement.

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34. ### A Reduction of Heteroscedasticity in Time Series

Hi, I have some crucial questions belong to statistics: First, How can we derive the variance function with respect to mean for a given data? Secondly, I would like to ask: what method should we employ if the variance in time series behaves like a high order (such as ##𝑎𝑢_𝑡^5+𝑏𝑢_𝑡^4+𝑐𝑢_𝑡^3##...
35. ### Reduction in gas concentration of water with solutes

When salt (polar) is added to water (polar) it makes the water more polar and causes the oxygen (non-polar) to be "driven" from solution. So I'm assuming this is an electrostatic repulsion(?). Aside from salt what other solutes would cause this to happen? Would a solute have to have very polar...
36. ### I Entropy & Coding: Proving Huffman Reduction Cannot Decrease

For {pi}i=1,n being the probability distribution, I want to show that a Huffman reduction cannot be decreasing, and I reached a point where I need to show that q+H(p1,...,pn-s,q) ≥ H(p1,...,pn), where q = pn-s+1 + ... + pn and s is chosen such that: 2 ≤ s ≤ m (m≥n) and s = n (mod(m-1)) where...
37. ### I Deriving reduction formula in Geometric Algebra

Hi, I am trying to learn Geometric Algebra by going through the book "New Foundations for Classical Mechanics" by David Hestenes. I was reading the part about reduction formula (shown below) but couldn't get the result the shown in the book. Can someone show me how iterating (1.15) gives the...
38. ### I Using PCA for variable reduction

In the textbook “Principal Component Analysis” Jolliffe (§9.2) suggests the following method for variable reduction: “When the variables fall into well-defined clusters, there will be one high-variance PC and, except in the case of 'single-variable' clusters, one or more low-variance PCs...
39. ### I Spectrum classification and dimension reduction

I am trying to distinguish two different plant species based on their chemical signature using statistical signal classification. This is what the average curves of two species look like with their standard deviation bounds: These spectra are made up of ~1400 points. So it was suggested to...
40. ### Investigating the Stoichiometry of Reactions 1 & 2

Cl2(g) + 2I–(aq) -->I2(aq) + 2Cl–(aq) (reaction 1) [2S2O3^(2-)(aq) + I2(aq) --> S4O6(2-)(aq) + 2I–(aq) (reaction 2) Why isn't n(I2)(reaction 2)=2n(S2O3^(2-))(reaction 2). I don't see why this is wrong. <edit: remove size and italics>
41. ### Standard Reduction potential of Fe

Homework Statement If E°(Fe2+/Fe) is x1 and E°(Fe3+/Fe) is x2 then find E°(Fe3+/Fe2+) 2. The attempt at a solution We need E for Fe3+ + e ----> Fe2+. We are given Fe2+ + 2e----->Fe is x1. Reversing will give Fe--->Fe2+ + 2e (-x1)...(i) also, Fe3+ + 3e----->Fe is x2, ...(ii) multiply (ii) by 2...
42. ### Solving a second order ODE using reduction of order

Homework Statement Hi there, I have an assignment which involves using reduction of order to solve for a second solution to an ode (the one attached). However this is a method I am new to, and though I have tried several times, I'm somehow getting something wrong because the LHS and RHS are not...
43. ### A Interdependent Recursive Equations

Hi, I have a system that I am trying so solve in terms of m, and have two recursive equations: The problem for me is that each recursion is dependent on the value from the other! I know that they are both solvable, however I have no idea what approach I could take to express each only in...

Why can't we use the NOTE method (exercise 4.21) on the exercise 4-156 ? A = ab/3 = (10.500)/3 = 1666,66 N --> this not right
45. ### MHB Staff reduction rate from annualized to monthly rates

Hi, If I have 100 staff at the beginning of the financial year and is ordered to reduce the workforce by 12%, ie I should have 88 on average at the end of the year. How would I calculate the monthly percentage so the reduction of staff can be rolled out gradually. I don't want to cut 12 in the...
46. ### Loss of energy in DC and loss reduction in AC circuits

Homework Statement similarities and differences of AC and DC current in simple circuits. Outline using diagrams and a clear desciption the loss of energy in DC circuits and power loss reduction of AC when transmitted. Homework Equations N/A The Attempt at a Solution DC loses energy over long...
47. ### A Multiverse reduction in the new Hawking/Hertog model?

Hawking and Hertog's new paper "A Smooth Exit from Eternal Inflation?" does away with the infinite multiverse of Hawking's previous theory and proposes a cosmology that predicts "a simpler and finite universe". But I can't figure out the extent of this reduction to a "simpler and finite"...
48. ### MHB Find determinant by row reduction in echelon

$\textsf{a. Find the determinants by row reduction in echelon form.}$ $$\left| \begin{array}{rrr} 1&5&-6\\ -1&-4&4 \\ -2&-7 & 9 \end{array} \right|$$ ok i multiplied $r_1$ by 1 and added it to $r_2$ to get $$\left| \begin{array}{rrr} 1&5&-6\\ 0&1&-2 \\ -2&-7 & 9 \end{array} \right|$$...
49. ### Are the terminals of a Battery neutral?

So I've been learning how batteries work. What I learned is that a battery consists of 2 pieces of metal both with different electronegativities. These metals react with an electrolyte. One metal (called the anode) is oxidized and has its electrons removed, leaving behind a positive ion which...
50. ### Engineering Use Circuit reduction, voltage and current divider to find i

< Mentor Note -- thread moved to HH from the technical physics forums, so no HH Template is shown > in the solution sheet, He took the 18 ohms parallel with the 9 ohms and not the 6 ohms. I don't understand why he took this approach. I was going to take 18 ohms parallel with the 6 ohms and find...