Uzi Vishne: Difference between revisions

From formulasearchengine
Jump to navigation Jump to search
en>PamD
Stub-sorting (you can help!)
 
No edit summary
 
Line 1: Line 1:
{{one source|date=December 2013}}
There are tons of property brokers in Singapore and it can be exhausting to distinguish the good from the bad. It is a big sum of money invested in property for most Singaporeans, be it commercial leasing or shopping for a home, so choose the precise property agent immediately by searching for these indicators. 1. Proactiveness<br><br>What you study in theory is barely a fraction of what you'll study arms on. There might be learning gaps as you go alongside the road as a realtor that will require you to verify with fellow agents on the standard practices and solutions for each problems you face. Typically, you're required to think on your feet. The agent disappears after the agreement is signed. He doesn't return the owner's call and there's no update from him. Three months go by very quick and the proprietor finally ends up with an unsold unit. Worse nonetheless, the market has gone down some more in the meantime. The proprietor swears off using a sole agent and begins telling everybody he is aware of not to do it. I hope I have given you a good idea of the pros and cons of appointing an exclusive agent.<br><br>I wish to thank your group and you for giving me practical data, strategies and formulas that I might not have gotten from wherever else. It was a really enriching expertise and I've discovered lots from this course. Someday, after attending your course, I managed to shut a detached house at $thirteen million in Jan 2013 for a document of $1500psf in Seletar Hills Tremendous Estate Agent Ivy Lee  [http://www.tinh1dem.com/tinh1dem/member/10398/blog/view/55057/ New launch sg] cracks the ranks of the large boys with spectacular sales of over $700 million is six years." We're fairly happy with Ivy. She's very palms-on, is responsive and delivers. That's all you need in a real estate agent." Singapore's top-earning actual estate agent Ivy Lee has an uncommon method of instructing her sons independence." Search Entire Job Ad Job Title Firm Name<br><br>The quantity of the safety deposit is often stated in the Letter or Intent. The standard apply in Singapore is usually one month's rent for every year of lease. It should only be payable upon signing of the Tenancy Agreement. When the lease term ends, the deposit will probably be refunded without interest. Nevertheless, the owner reserves the precise to deduct from the deposit all costs and expenses arising from the tenant for breaching any of the covenants stated in the Tenancy Settlement.<br><br>In direction of the end of the four years of us being at The Jade, we contacted "H" and "A" to ask what they supposed to do as we would be completely happy to re lease the property if the rental quantity was agreeable. However "H" had not decided what he was going to do and he would get again to us by mid December. Estate agents are obliged to show their license card, and purchasers have a proper to demand to see them. Online ads in at the least 5 property websites = Minimal $200 (Primarily based on 1 month publicity per ad) You'll want to know find out how to comply with-up and seemingly compromise on your calls for with out giving the patrons any impression that you're desperate to sell. In addition, it's good to manage all closing particulars, any of which might cause the sale to fall by means of. Actual Property Company<br><br>There is no regulation on the amount of fee. Fee is barely payable upon full switch of the property. If for any purpose the deal falls by, then he receives nothing from the vendor (vendor) or the owner (owner). He has no right to get better whatever expenditure he has incurred in attempting to bring a few sale or tenancy. He takes the business risk of shedding his bills and time when his recommendation just isn't accepted by the seller or the landlord. Brokers should always use their agency's official settlement.<br><br>simply wished to rant about my lousy expertise with a specific property agent!! this Darren Ng from Dennis Wee Group, simply finish the transaction worth 2.4million on a foul notice. he simply gave his luck away, due to his double-head snake angle and actions, i dont assume i wish to cope with such an agent anymore. there are such a lot of agents on the market, he positively lost a repeat customer. my authentic put up was over three and a half years in the past and to at the present time, there's still no single, helpful, authority to appropriately handle complaints. we are looking for an avenue to address problems at hand, not for you advertise agents. Landlords pay a half month price of rental as commission for each year of rental. Methods to discover a good and dependable real property agent
 
{{Orphan|date=November 2013}}
 
The '''Sandia method''' (also known as Veers method) is a method for generating a turbulent wind profile that can be used in aero-elastic software to evaluate the fatigue imparted on a turbine in a turbulent environment. That is, it generates time series of wind speeds at a set of points on a surface, say the plane of the rotor of a wind turbine. Analysis is performed initially in the frequency domain, where turbulence can be described quantitatively with more ease than the time domain. Then, the time series are obtained by inverse fast Fourier transforms.
 
In its original form, the Sandia method only simulates the u-component of the wind; that is, the wind was modelled as propagating in a direction perpendicular to the plane of the rotor. Work carried out by NREL, specifically Kelley, suggested that a considerable amount of turbulent energy existed in the v-component (the v-component is parallel to both the plane of the rotor and the Earth). As such, the Sandia method was upgraded such that it included the v-component and w-component. Further upgrades have been performed such that the wind profile exhibits cross-axis correlation (turbulent fluctuations in one component being somehow connected to turbulent fluctuations in another). However, these are not considered in this article.
 
== Point-wind speed spectra ==
 
Although turbulence leads to unpredictable results in the time domain, it can, to some extent, be characterized in the frequency domain. Turbulent fluctuations are dominated by low frequency components, with higher frequency components having less influence. For further information, see [[Turbulence#Kolmogorov's theory of 1941|Kolmogorov's theory on turbulence]].
 
Several models of frequency domain representations of point wind speeds have been developed: the [[von Kármán wind turbulence model]] and [[Dryden Wind Turbulence Model]] are examples of such.
 
===Discretizing a spectrum ===
 
A spectrum in its original form is a continuous function. However, computer programmes operate on discrete functions. Thus a modification to whatever type of spectrum, be it Kaimal, von Karman, or some other spectrum, is needed. This is given below:
 
:<math>
S(\omega_k) = S(\omega = \omega_k)\Delta\omega/2
</math>
 
where <math>S(\omega_k)</math> is the discretized spectrum evaluated only at the discrete frequencies <math>\omega_k</math>, <math>S(\omega = \omega_k)</math> is the continuous spectrum evaluated at <math>\omega = \omega_k</math> and <math>\Delta\omega</math> is the size of the step between consecutive frequencies being considered.
 
== Coherence ==
 
When generating a time series of wind speeds for a set of points across a surface, coherence needs to be taken into account. That is, the instantaneous wind speed at some point, A, will bare some resemblance to the wind speed at some other point, B. Clearly, the resemblance is influenced by the separation of points A and B. That is, two points separated by a large distance will show less similarity to each other than two neighbouring points on the surface.  
In addition, one would expect low frequency components of the wind speeds at points A and B to show more correlation than high frequency components. As such, many coherence functions have been proposed: Davenport, Solari, etc. The Solari coherence spectrum is provided as an example:
 
:<math>
Coh_{ijk} = \exp^{-2C\Delta r_{ij} \omega_k/(u_i + u_j)}
</math>
 
where <math>C</math> is a constant, <math>\Delta r_{ij}</math> is the separation of points <math>i</math> and <math>j</math> on the surface, <math>\omega_k</math> is the frequency, and <math>u_i</math> and <math>u_j</math> are the mean wind speeds at points <math>i</math> and <math>j</math> respectively. The indices <math>i</math> and <math>j</math> run from 1 to n, and the index <math>k</math> covers the frequency range. From the coherence function stems the coherence matrix. To cover all relationships between all points, the coherence function must be an <math>n^2</math>-by-<math>n^2</math>-by-<math>\omega</math> matrix. Clearly, the coherence matrix is symmetric about the main diagonal if we are restricting ourselves to looking at the coherence function at a single frequency. This is because the spatial separation between points A and B is the same as the spatial separation between B and A. That is, for a n-by-n grid, only <math>(n^4 + n^2)/2</math> elements need to be calculated for each frequency.
 
It is worth noting at this point that whilst the coherence matrix is strictly a 3-dimensional matrix (i, j, and k), computer programmes which implement the Sandia method typically reduce the coherence matrix to a 2-dimensional matrix where the frequency dimension has been 'removed'. This is to ease computational requirements. A 2-dimensional matrix is also required to perform some of the actions on the spectral matrix, such as a Cholesky decomposition, which is mentioned later. Of course, variation in frequency is still applied. However, the following process is carried out in full for one given frequency before proceeding to the next frequency. As such, in the following section, a power spectrum refers to the value of the power spectrum at a given frequency and not the full set of values across the frequency range being used. That is,
 
:<math>
Coh_{ijk} \rightarrow Coh_{ij}(\omega_k)
</math>
 
and
 
<math>
S_{ijk} \rightarrow S_{ij}(\omega_k)</math>
 
where an element of S, <math>S_{ijk}</math> , would have given the strength of the spectrum at a particular frequency <math>\omega_k</math> at a particular point in space.
 
== Generating turbulence ==
 
Power spectra are needed for each of the <math>n^2</math> points on the surface; this encapsulates information about the turbulence intensity for each point. It should be noted that under IEC standards, only one power spectrum is used; that is, all <math>n^2</math> points have the same turbulence intensity.
 
With the power spectra, the spectral matrix can be formed. This a <math>n^2</math>-by-<math>n^2</math> matrix. The main diagonal of the spectral matrix contains the previously defined spectra for all <math>n^2</math> points on the surface. The off-main diagonal elements contain all the cross spectra between the points. The cross spectra are determined by the following function:
 
:<math>
S_{ij}(\omega_k) = Coh_{ij}(\omega_k)\sqrt{S_{ii}(\omega_k)S_{jj}(\omega_k)}
</math>
 
Due to the symmetry of the coherence matrix, only <math>(n^4 + n^2)/2</math> elements are independent. This property can be exploited to lighten memory requirements when writing a programme to simulate the Sandia method.
 
The spectral matrix, <math>S(\omega_k)</math>, can be written as the matrix product of a matrix, <math>H(\omega_k)</math>, and its transpose. That is,
 
:<math>
S(\omega_k) = H(\omega_k)H(\omega_k)^T
</math>
 
<math>H(\omega_k)</math> is ultimately needed to obtain the complex Fourier co-efficients of the Fourier transforms of the time series of the wind speeds at all the points on the surface. Note - if the Fourier transform of a time domain function, <math>x(t)</math>, is <math>X(\omega)</math>, then the resultant spectrum is <math>S(\omega) \propto X(\omega)X^*(\omega)</math>; for multiple time domain functions, the Fourier co-efficients can be stored in a matrix, which then means that the above equation is applicable.
 
Obviously, there are an infinite number of solutions to the above expression; consequently, the assumption that <math>H(\omega_k)</math> is a lower triangular matrix is made such that only one solution exists. The solution can be found via a Cholesky decomposition. The resultant <math>H(\omega_k)</math> matrix can be thought of as can be thought of as the weighting factors for the
linear combination of N independent, unit-magnitude, white-noise inputs that will
yield N correlated outputs with the correct spectral matrix.<ref>Veers - Three-dimensional wind simulation</ref>
 
To get the complex Fourier co-efficients associated with the Fourier transform of the time series of the wind speeds, a column vector, <math>V</math> is obtained by multiply the <math>H(\omega_k)</math> matrix by a column vector containing <math>n^2</math> values of Gaussian white noise, <math>X(\omega_k)</math>, as shown below:
 
:<math>
V(\omega_k) = H(\omega_k)X(\omega_k)
</math>
 
The column vector gives the Fourier co-efficients for all points on the grid at a given frequency. This is then built up into a two dimensional matrix which covers the complex Fourier co-efficients for all points across all frequencies. Then, an inverse fast Fourier transform is performed to get the time series. That is,
 
:<math>
V_i(\omega_k) \rightarrow V_{ik}
</math>
 
==References==
{{reflist}}
 
[[Category:Wind]]
[[Category:Fluid dynamics]]
[[Category:Wind turbines]]

Latest revision as of 16:34, 1 October 2014

There are tons of property brokers in Singapore and it can be exhausting to distinguish the good from the bad. It is a big sum of money invested in property for most Singaporeans, be it commercial leasing or shopping for a home, so choose the precise property agent immediately by searching for these indicators. 1. Proactiveness

What you study in theory is barely a fraction of what you'll study arms on. There might be learning gaps as you go alongside the road as a realtor that will require you to verify with fellow agents on the standard practices and solutions for each problems you face. Typically, you're required to think on your feet. The agent disappears after the agreement is signed. He doesn't return the owner's call and there's no update from him. Three months go by very quick and the proprietor finally ends up with an unsold unit. Worse nonetheless, the market has gone down some more in the meantime. The proprietor swears off using a sole agent and begins telling everybody he is aware of not to do it. I hope I have given you a good idea of the pros and cons of appointing an exclusive agent.

I wish to thank your group and you for giving me practical data, strategies and formulas that I might not have gotten from wherever else. It was a really enriching expertise and I've discovered lots from this course. Someday, after attending your course, I managed to shut a detached house at $thirteen million in Jan 2013 for a document of $1500psf in Seletar Hills Tremendous Estate Agent Ivy Lee New launch sg cracks the ranks of the large boys with spectacular sales of over $700 million is six years." We're fairly happy with Ivy. She's very palms-on, is responsive and delivers. That's all you need in a real estate agent." Singapore's top-earning actual estate agent Ivy Lee has an uncommon method of instructing her sons independence." Search Entire Job Ad Job Title Firm Name

The quantity of the safety deposit is often stated in the Letter or Intent. The standard apply in Singapore is usually one month's rent for every year of lease. It should only be payable upon signing of the Tenancy Agreement. When the lease term ends, the deposit will probably be refunded without interest. Nevertheless, the owner reserves the precise to deduct from the deposit all costs and expenses arising from the tenant for breaching any of the covenants stated in the Tenancy Settlement.

In direction of the end of the four years of us being at The Jade, we contacted "H" and "A" to ask what they supposed to do as we would be completely happy to re lease the property if the rental quantity was agreeable. However "H" had not decided what he was going to do and he would get again to us by mid December. Estate agents are obliged to show their license card, and purchasers have a proper to demand to see them. Online ads in at the least 5 property websites = Minimal $200 (Primarily based on 1 month publicity per ad) You'll want to know find out how to comply with-up and seemingly compromise on your calls for with out giving the patrons any impression that you're desperate to sell. In addition, it's good to manage all closing particulars, any of which might cause the sale to fall by means of. Actual Property Company

There is no regulation on the amount of fee. Fee is barely payable upon full switch of the property. If for any purpose the deal falls by, then he receives nothing from the vendor (vendor) or the owner (owner). He has no right to get better whatever expenditure he has incurred in attempting to bring a few sale or tenancy. He takes the business risk of shedding his bills and time when his recommendation just isn't accepted by the seller or the landlord. Brokers should always use their agency's official settlement.

simply wished to rant about my lousy expertise with a specific property agent!! this Darren Ng from Dennis Wee Group, simply finish the transaction worth 2.4million on a foul notice. he simply gave his luck away, due to his double-head snake angle and actions, i dont assume i wish to cope with such an agent anymore. there are such a lot of agents on the market, he positively lost a repeat customer. my authentic put up was over three and a half years in the past and to at the present time, there's still no single, helpful, authority to appropriately handle complaints. we are looking for an avenue to address problems at hand, not for you advertise agents. Landlords pay a half month price of rental as commission for each year of rental. Methods to discover a good and dependable real property agent

Retrieved from "https://en.formulasearchengine.com/index.php?title=Uzi_Vishne&oldid=296930"