Backward Propagation Tutorial


 
Introduction
Backward Propagation is probably the most common method for
training forward-feed neural networks. A forward pass using an input pattern
propagates through the network and produces an actual output. The backward
pass uses the desired outputs corresponding to the input pattern and updates
the weights according to the error signal.
There are hundreds of papers covering the subject of backward
propagation. Unfortunately, many of them tend to exhibit a vast stockpile
of equations and complicated partial derivatives with undefined variables
to explain a concept that is really quite simple. Quite often, a pseudocode
algorithm or an example with pictures is the most effiecient method to convey
information.
Artificial Neuron Anatomy
請稍等，圖片正在下載中...
 
w --> weight

I --> input

O --> output

A --> activation value
Think of the activations as a pulses of electricity traveling
along the dendrite path. Each activation pulse is multiplied by the weight
of the dendrite it is traveling along. When all inputs to the neuron have
been "stimulated" with this pulse, the neuron adds up these products
and performs a thresholding or "squashing" operation on the resulting
sum. The result of the squashing fun...

症狀是用Control Panel的uninstall/repair，或者源安裝盤，都在load某個component時掛掉，不能進入正常安裝界面，然後彈出對話框，提示“A Problem has been encountered while loading the setup components. Canceling setup.”

而Log中顯示錯誤
MSITOSIT: [2] ERROR processed; exception was thrown for retail build
Developer Comment: : has no associated directory, verify the Feature table is correct
Build Time: Thu Dec 11 14:04:18 2003
HRESULT: -2147467259

網上查了一下，有的說是SP1的問題，有的說是Kaspersky的問題，我這裏都不管用。

最後的解決辦法是找到源安裝盤的vs_setup.msi，用Admin進入cmd，運行msiexec /x vs_setup.msi，它似乎就什麼都不檢查，就能卸載了。

之後重裝也沒問題。

To add additional information to domain users it is necessary to use the Profiles API. Since the release of this API, the Shared Contacts API should be use only for external contacts. For more information see:
http://code.google.com/apis/apps/profiles/developers_guide_protocol.html

錯誤789：L2TP 連接嘗試失敗,因為安全層在與遠程計算機進行初始協商時遇到處理錯誤

增加注冊表項(以下操作均在客戶端完成)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RasMan\Parameters

"ProhibitIPSec"=dword:00000001

然後重啟機器