IndarKness

IndarKness

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Posts by IndarKness

Bleeding Emergency

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These days I am very “busy”.  It can be described as “bleeding emergency”.  The application for graduate is just a step away deadline.  The final exams are coming straight without any hesitation.  As a song needed to be played in final piano exam, akasuki no kuruma (a song in Mobile Suits Gundam Seed, which means Wheels of Dawn) could be my song only if it was practiced and practiced.  Hope everything goes fine!

P.S.  Although I like “hoshi no arika” (a song in Legend of heroes VI: Sora no Kiseki, which means Whereabouts of the Stars) better, akasuki no kuruma is a good song.

This is a video of akasuki no kuruma.  I am proposed to play piano exactly as same as it.

This is a video of hoshi no arika. I want to play it with my harmonica after all application work finishes.

10kg Plan

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Having not blogging for a long time…

I am too thin…  I think I should try to gain weight.  After ask an expert, I found his secrets.

1.  Five meals a day.  Eat at 8, 11, 15, 18, 21 o’clock

2.Exercise 1 hour a day.

It is sad that I can’t translate the detail of exercise into English.  I tried to follow the plan but failed on 2010/11/30.  Now I want to try again.

P.S.  I bought kinect from U.S.  Hope xtreme will be released on time.

Old Friend

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It is a special day. I found an old friend in Renren, a Chinese Facebook clone, who I haven’t met for more than 14 years!
He is a specialist on car unlocking, earning more than 20,000 RMB/mo without a college degree. It is interesting.
I am chatting with him. More information on professional career will be provided.

L2TP over IPV6 Router

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I posted l2tp over ipv6 before. It is a patch file for xl2tpd from Cheng Li, which enable xl2tpd working under ipv6 network for Windows Vista/7 VPN Clients.

And this is the openwrt firmware for buffalo whr-hp-g54 from Cheng Li which includes the hacked xl2tpd. After flashed the hacked firmware, buffalo whr-hp-g54 can connect l2tp server under IPV6.

I just bought Linksys WRT54GS v3. Hope it works.

These are the links you may concern:

Blog Post: L2tp over IPV6 in Linux
Hacked buffalo firmware

P.S.  It is really easy to compile your own openwrt firmware.  Just put the patch file into the patch folder of xl2tpd in the openwrt source code, change its file name and make sure it would be patched at last.  The makefile should be modified cuz the patch file is only for xl2tpd 1.2.4.

Fail on Hackitosh

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Kane’s Talent Show Opening Movie is so amazing that I want to install a Mac on my laptop. I thought it would be easier cuz I have installed Mac OS 10.5.7 successfully on my last laptop. The success was really lucky cuz all the devices were almost as same as apple’s. But it turned out this time would be much more difficult.

I flashed my BIOS to a leak version which turn on Hardware DEP by default. And then VMware is installed and I tried to get Mac setup in Virtual Machine. It was not a success. Due to hatred of low speed, I didn’t tried workaround.

I wrote Snow Leopard Retail DVD (MBR modified) into my HDD, then used grub4dos to start iBoot. It worked well until I rebooted. Mac installer made Windows Partition inactive, OK, set it active. No Graphic card, sound card and Wired Network installed, OK find the driver. After I tried Multibeast to patch kernel, my laptop froze at BIOS logo!

Maybe the script did some operation on EFI or something. Eject my SSD, insert it into another computer as slave, delete Mac Volume…OK everything works fine again, everything come back to start again.

I’ll try again when I am free.

Kane vs Alex

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Kane Hsieh is an amazing guy.  He is using Intel X25-18M SSD as same as mine.  He is a definitely computer geek.  And he is a cyclist,too.  It’s really fabulous to find a guy you have so many things to share with.  After the cyclists’ exchange, I was thinking the paragraph on the feedback…OK, it’s just joking.  The point is, I will get the world’s most special cycling jersey.

OK, it’s late, leave the headquarter and grab a pillow for sleep.

Summer Note 2-The Adjoint Method

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The outline can be listed below:
1. The bounded linear operator, and the continuity definition of a linear operator, which is equivalent to: bounded or continuous at the origin.
2. The dual space, which is defined as a real bounded linear function.  The adjoint operator definition:
Let [latex]T:X \to Y[/latex] be a bounded linear operator between Banach spaces X and Y.  The adjoint operator [latex]T^{*} : X^{*} \to Y^{*}[/latex] can be constructed as: [latex]T^{*} (F)(x)=F(T(x))[/latex] for all [latex]x\in X, F\in Y^*[/latex]
Because every bounded linear operator over a Banach space X can be reconsidered as inner product:
[latex]F(x)=<x,y>[/latex]for all [latex]x\in X[/latex] and [latex]||F||=||y||[/latex] Here y is only linked with F.
So it is a comparatively simple step to define the inner product form of an adjoint operator [latex]y^*[/latex] instead of the function form[latex]T^*[/latex]:
[latex]F_T(x):=<T(x),y>=<x,y^*>[/latex] for all [latex]x\in H[/latex]
3. The differentiability definition in a Banach Space:

Gateaux differentiable at [latex]x_0[/latex]

[latex]DT(x_0;h):=\lim_{\epsilon \to 0} \frac{T(x_0+\epsilon h)-T(x_0)}{\epsilon}[/latex]

Frechet differentiable:

[latex]\lim_{||\delta x||\to 0}\frac{||T(x_0+\delta x)-T(x)-T’(x_0)\delta x||}{||\delta x||}=0[/latex]

They are equal when the two equations exist on all [latex]x,\delta x \in X[/latex]

The partial Frechet derivative [latex]D_x(x_0,y)[/latex]of an operator:

[latex]\lim_{||\delta x|| \to 0}\frac{||U(x_0+\delta x,y)-U(x_0,y)-D_x(x_0,y)(\delta x)||}{||\delta x||}=0[/latex]

Because the differentiability is defined by limit equations, the notion of the chain rule applies to operators that are continuously Frechet differentiable.

Then it comes the optimal question, I had the problem on figuring out the two functions given: [latex]J(\rho,\lambda),E(\rho,\lambda)[/latex].  [latex]J(\rho,\lambda)[/latex]is the cost function and [latex]E(\rho,\lambda)=0[/latex] is the solution of [latex]\frac{\partial \rho(x,t)}{\partial t}+\frac{\partial}{\partial x}(v(\rho)\rho(x,t))=0[/latex] with conditions.

Because [latex]\rho[/latex] is a function of [latex]\lambda[/latex], [latex]J(\rho,\lambda)[/latex] can be seen as [latex]j(\lambda)[/latex].  Then the book gives 3 conditions assumed, which assume everything is continuously Frechet differentiable.  I have some problems here.  I can’t understand how he find these 3 assumptions.  Hope it will be clear when I reading the calculation part.

I should look up the details on Lagrangian operator.  The only thing I know in calculating minimum is Lagrange multipliers.  Which is said not work during the semiconductor factory problem.  I will update the Algorithm For Solving when I am ready.

Summer Note 1 – Mathematical Models for Control Systems

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It has become a problem that nowadays control system is getting complex. To describe, calculate, and optimize production, 3 classical mathematical models are introduced.

1.Discrete event simulation: very accurate but hard to calculate complex models. Probability distribution calculation needed. Distribution functions calculability limited by sample accessibility.

2.Queueing networks: fairly accurate (using average data) but hard to calculate complex models. Only works with steady models (time infinite).

3.Fluid Models (ODE): [latex]\frac{dq(t)}{dt}=\lambda(t)-\sigma(t)[/latex]
It describes queue change rate is influx rate minus outflux rate.
It is easy to calculate. But it uses average data (no possibility included), which may lead to trivial results. And [latex]\lambda(t)[/latex] and [latex]\sigma(t)[/latex] are not easy to find.

So the author introduced a new model: Continuum Model
It uses a totally new view. The model doesn’t put too much attention on the physical position. A new attribute is introduced for each item, stage x, from 0% to 100%. Then the completion of a item can be involved into mathematical calculation.
The core equation is:
[latex]\frac{\partial \rho (x,t)}{\partial t}+\frac{\partial}{\partial t}(v(\rho)\rho (x,t))=0[/latex]
The function [latex]\rho (x,t)[/latex]is the density, when the stage is x and time is t.

It took me some time to understand the equation. I think it is just like the flood in Yangtze River now. The height of water is the function [latex]\rho (x,t)[/latex], over position x and time t.
The equation is setup up like this because the change of [latex]\rho (x,t)[/latex] over time(x fixed) is just like the change of the height of water. It is caused by the different velocity of water over position x. The different velocity is describe as the [latex]-\frac{\partial}{\partial t}(v(\rho)\rho (x,t))[/latex].
Here the author uses [latex]v(\rho)[/latex], which describe moving speed of 1 item (just like 1 water molecule in Yangtze River).

The velocity [latex]v(\rho)[/latex] is defined by:  [latex]v(\rho)=\frac{v_{max}}{1+\int_0^{1}\rho (s, t) ds}[/latex]

or by [latex]v(\rho)=v_{max}(1-\frac{\int_0^{1}\rho (s,t) ds}{L_{max}})[/latex].  Here [latex]L_{max}[/latex] is the max load.

I haven’t looking up the article where these two definition come from.  But it can be concluded from experience I think.

In this model, the changing chain: influx–WIP–velocity–outflux

Lost&Found

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It is a blog written in Chinese.

思绪很乱很杂,我各种语言又不好,没有条理请见谅。

引子

这几天事情很多,3天前林说了新加坡现在的状态,让我很无奈。2天前N说了下现在的英国状态,让我更无奈。客观上某个国家的状况会直接影响我的判断,因为我并没有想好我到底要读什么,我只是想着,只要一个比上海平静的地方,过着比民工高级的生活,享受着比屁民更好的福利,就行了。当强烈经济衰退和华人歧视摆在眼前的时候,我就会退缩,因为这些决定不是灵魂决定的,是物质取向的。

今天牛又有一篇老长的文章对数学系的抱怨。的确,三年了,我根本不知道自己要什么,也不知道自己该怎么做。N暑假在家,每天早晨5点起床,就是为了多读一本书,那么OK,我明天也5点起床好了,那么我该读哪本书呢?真的,想不出来,我该读哪本书。除了GRE和Toefl摆在眼前,我必须要背单词,除了这个,我真不知道,自己该读什么,该看什么,该学什么。

(more…)

Finally it is all over.

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I can  proudly announced that I almost finish all the courses required by Fudan Mathematic School now.  After the final exam passed(hope I won’t get an ‘F’) I have to find a new place to put myself in, a college, a workyard or something else.

I am now the oldest student in my school(Compared with other pre-bachelor).  How is the passed three years, I don’t know.  But I will be informed by the world, in the following months.

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