Ponson's Tribe

2015-11-25T00:53:00.002-08:00

書中介紹了幾個好用的tool，可以提升作筆記的效率。

[Book]這才是數學

2015-10-29T00:37:00.001-07:00

感覺可從作者的著作中了解到數學的本質，數學的本質是什麼？可以從<<這才是數學>>這本書中了解到，有一些以前所背誦的公式，其實本身並沒有太多深奧的道理，只要用心多想想，其實，很容易就可以舉一反三，但仍是要動動腦，是一本需要花時間好好研讀、「計算」的書。只不過，有一個可惜的地方是，書中常會提出很多留給你思考的問題，但沒有給出答案。其實，這樣很好，只是我急著想繼續看下去，也一時沒有想法，沒辦法像一個數學家那樣好好地把玩「數學實在」裡的有趣事物，或許把整本書看完之後，「有空」會找其中幾個問題來想想、驗證，不過，我可能還是會繼續以看其他的書為優先吧！圖書館借書已到期，沒辦法只能先還，以後有機會再借來看看了。

看到 p.68，對角線度量方法還沒看......(待續)

以下列舉書中的句子

你自己訂的題目，就是最好的題目。(p.25)
數學家的特質並不是學術技能或淵博知識，而是永不滿足的好奇心，以及對簡單之美的渴望。做自己，去你想去的地方。與其裹足不前、害怕挫折或是困惑，不如試著擁抱這份恐懼和神秘感，開開心心大玩特玩一番。(p.25)
在許多方面，對稱是最強大的數學工具。(請把它放進你的求生背包裡。)(p.26)
藉由不只一種方法，能夠對問題有更深一層的理解和認識。(p.29)
數學家總是先做假設，再看看會發生什麼情況(古希臘人甚至創了一個詞來形容他-稱為分析，analysis)(p.32)
本質上說，作數學就是在玩耍、觀察和發現、建構例子(以及反例)，提出猜想，然後證明 --- 這也是最困難的部份。(p.32)

[Linux][InputMethod] gcin install and setup. Hsu style keyboard

2014-11-02T04:15:00.000-08:00

安裝完Linux後的幾件事之一就是要安裝好中文輸入法，偏偏敝人只會使用許式鍵盤注音，因此必須尋找的合適的輸入法才行。目前在Linux上，詞音輸入法應該是其中一個不錯的選擇。
One of those things you should do after you have installed Linux is to install the Chinese input method. The only input method I have learned is Hsu's input method, so I need find out the input method which support Hsu's keyboard. 「詞音」is a good choice to use it.

在Linux Lmint 17必須先自行安裝gcin，可透過 Synaptic 套件管理程式直接進行安裝，安裝完後執行command "im-config"，將預設的輸入法框架改為gcin後，須重新啟動X window一次。
You should install gcin by yourself after installed Linux Lmint 17. You can use Synaptic Package Manager to install it directly. Then type the command "im-config" in terminal to setup gcin as your active input method framework. Then you'll be asked to restart X window again.

之後就能按Ctrl + Space去切換到詞音輸入法了。
After that, you can use Ctrl + Space to switch the input method to 「詞音」 input method.

到選單，選擇「gcin 輸入法設定」，選擇「詞音」的設定選項，就可在其中設定鍵盤為「許式鍵盤」
For the menu, type 'gcin', then select 「gcin input method setup」。Then select the setting item of 「詞音」，you can setup the Hsu's keyboard there.

[Linux][WiFi]How to install the driver of WiFi USB SAPIDO AU4912 (Realtek 8192cu)

2013-10-11T09:03:00.000-07:00

因為他很小，而且號稱支援Linux，因此就買了這顆WiFi USB dongle "SAPIDO AU-4912"。但在Linux CentOS上使用一直有問題，之前的解決方法，是打電話給SAPIDO客服，他提供給我另一個driver，要我自行編譯、安裝此driver，過程有些辛苦，compile的過程一直出錯，缺東缺西的，因為compile所需對應的檔案都太過老舊，都需要一個一個另外從網路下載回來，終於搞定。但感覺連線的速度很慢，可是因為能用，也就將就著用了。
Because it's small and announced to support Linux. I buy the WiFi dongle "SAPIDO AU-4912". But it can't be used in CentOS. The first solution that I used was to call SAPIDO customer service for help. He gave me another driver but need to compile by myself. It's hard to fix the compile errors because the version of driver was too old. I need to download some related packages to fix the errors. But it worked. Although the speed of data is a little slow, at least, it worked.

最近改裝Ubuntu 13.04 (真的滿難用的，幾小時後馬上改成 Linux Mint，LUbuntu 也不錯啦，適合硬體等級較低的電腦，但make, gcc等，都要另外裝)，以上三套發行版安裝好後，都可以連上WiFi AP，但很難連，又很容易斷線，而且因為跟CentOS屬於不同的package方式，實在不想重找一次，只好繼續爬文，後來看到有網友建議，直接安裝Realtek 的driver來試試看,但還是會compile error，目前有找到兩個solution可以解決此問題，建議可先用solution1。
Solution 1:
https://github.com/pvaret/rtl8192cu-fixes
頁面下方直接提供安裝的commands，一步接一步就可完成了。
The page contains the commands of installation. It's easy to follow the steps to finish the installation.

Solution 2:
從http://askubuntu.com/questions/290452/installing-workaround-realtek-drivers-for-edimax-but-getting-error 裡有網友修正的patch並放在git上，實在是太感恩了！終於可以正常連線，而且連線速度看起來也恢復正常水準。
Recently, I tried to install Ubuntu 13.04(it's really hard to use. After several hours, I changed it to Linux lint. LUbuntu is also not bad. It's suitable for old computers, but you need to install make, gcc, etc by yourself first), it can use the WiFi dongle without install additional drivers, but not stable and very easy to disconnect. So frustrated. I don't want to compile the old version of driver which SAPID customer service provided again, because the package is not the same as CentOS needed. I keep to find out solution on web. Some suggest to use the Realtek's driver directly, but it also failed to compile successfully. But in the link http://askubuntu.com/questions/290452/installing-workaround-realtek-drivers-for-edimax-but-getting-error someone fixed the bug and share his code. Thanks God! Finally it worked again, and the speed is normal.

cmd 節錄如下：
/* Get code and compile */
git clone https://github.com/dz0ny/rt8192cu.git
cd rt8192cu
make
sudo make install

/* Rmove old WiFi module and install new one */
sudo modprobe -r rtl8192cu
sudo modprobe 8192cu

如果要讓每次開機都能用到新的driver，在/etc/modprobe.d/blacklist.conf 的最後加上一行
/* Prevent to use the old one when power on the computer */
blacklist rtl8192cu

2013-10-11T03:24:00.002-07:00

[OpenSUSE][Github]How to generate SSH public key in Linux for github

2012-09-30T08:41:00.000-07:00

How to generate SSH public key in Linux for github

When you first use github in Linux, for example: Open SUSE, you may suffer one problem is Error: Permission denied (public key). You can follow these steps below to generate public key and use it on github.

1. cd ~/.ssh
   Check the folder is exist or not? If yes, got to 2. to backup and remove existing SSH keys. If no, got to 3.

2. mkdir backup_folder
   cp id_rsa* backup_folder
   rm id_rsa*

3. ssh-keygen -t rsa -C "your_email@youremail.com"
4. create pbcopy, pbpaste cmds which are useful in Mac OS.
4.1 install XSel tool. You can use cnf xsel to check the cmd to install XSel. The install cmd is sudo zypper install xsel.
4.2 add these 2 lines in ~/.bashrc
      alias pbcopy='xsel --clipboard --input'
      alias pbpaste='xsel --clipboard --output'

5. pbcopy < ~/.ssh/id_rsa.pub
   This cmd is used to copy public key content to system clipboard for later use.

6. Go to your github account setting page. Click "SSH Keys" column. Then click "Add SSH key" and paste the public key conent.

7. ssh -T git@github.com
   Check to see you're authenticated from github. Done.

[OpenSUSE][Java] Install JDK in OpenSUSE 12.1

2012-08-22T08:06:00.000-07:00

1. Download jdk, jre, then install
jre-7u6-linux-i586.rpm
jdk-7u6-linux-i586.rpm

2. sudo rm /etc/alternatives/java
3. sudo ln -s /usr/java/jre1.7.0_06/bin/java /etc/alternatives/java

[Ubuntu] 查詢某個目錄下的總容量

2011-05-24T02:35:00.000-07:00

du -sh "path"

[Ubuntu]查詢某個目錄下的特定檔案中的字串

2011-02-22T06:42:00.000-08:00

find . -name "*.java" -print -exec grep -n CameraHolder {} \;

查詢目前目錄下，檔案名稱為 *.java 之中，含有CameraHolder的字串

[Android]ERROR/Database(241): at android.database.sqlite.SQLiteDatabase.native_setLocale(Native Method)

2010-12-24T02:01:00.000-08:00

synchronized(this) {"put your database code here"}

ps: need time to prove it. :)

[Android] How to set default input method

2010-11-30T23:31:00.000-08:00

If you want to build a system which default input method is not Android default keyboard. You can use this way.

LINUX\android\frameworks\base\services\java\com\android\server\InputMethodManagerService.java

private boolean chooseNewDefaultIMELocked() --> modify what you want here.

[Android] Android market can't download

2010-10-21T04:22:00.000-07:00

Fxxk, fuxk, fxuk!!!

Finally, this should be a "Temp" solution. Google! Please fix it soon!!!!

[Android]How to simulate SD card without a real SD card?

2010-10-18T04:39:00.000-07:00

Only test for Froyo 2.2

If your SD card of develop target was broken or something else, the temp solution may keep you going...

We mount an internal folder to replace the read SD card.

There are 2 files need to be modified.
1. init.rc
* export EXTERNAL_STORAGE /mnt/sdcard
change it to
export EXTERNAL_STORAGE /data/sdcard

*mkdir /mnt/sdcard 0000 system system
disable this line

* add below lines under mkdir /acct/uid
mkdir /data/sdcard 0777 system system
symlink /data/sdcard /sdcard
mkdir /data/sdcard/DCIM 0777 system system
mkdir /data/sdcard/DCIM/100ANDRO 0777 system system

* symlink /mnt/sdcard /sdcard
disable this line

* add below lines under chmod 0771 /data
chown system system /data/sdcard
chmod 0777 /data/sdcard

2. Environment.java

Always return MEDIA_MOUNTED in function getExternalStorageState()

3. Modify related code if need in your application

[Android]Why the lib didn't build into target?

2010-10-18T04:32:00.000-07:00

In fact, the module of lib will build into target if we don't write specific tag into Android.mk.

For example, if we write this line into Android.mk

LOCAL_MODULE_TAGS := optional

Build system will skip this module, not build it into target.

[Android]How to use PopupWindow class

2010-08-29T07:07:00.000-07:00

Search key words:
1.

[RD]開發階段前應該要有的準備工作

2010-07-31T06:19:00.000-07:00

Step1: Survey solution
要盡可能的找到可以運用的Resource，把所有可能性在最短時間列出來，然後跟老闆報告全部需要Survey的時間，這樣才能說服老闆你需要花多久時間來Survey?

Step2: Candidate proposal
把可能的選擇性列出來，必須對相關的code base 以及所有資料詳加研讀，至少要涵蓋到state machine以及main function flow

Step3: Psudo implementation
把要新增或修改的功能，實際上想過一遍，要將過程中任何可能會造成Risk的地方都必須先寫出test sample，確認一下可行性。

Step4: Write SHD (Softeware High level Design)
前面3點都確實執行完畢之後，再來寫Design spec。

重點是:我們必須要先提出我們確實想要進行的項目有哪些？(包括Survey, Study, and Verify the possiblity等階段)，才有具體的理由爭取到時間。

[Eclipse]What is Mylyn?

2010-07-26T08:34:00.000-07:00

You can said "Mylyn" project is a task management project. It can help you to trace your tasks.

In the tutorial and the official user guide ,both said you can Window -> Show View -> Other... -> Mylyn -> Task List. In fact, you can't follow it successfully. In the new version (Greater than 3.5) seems remove the path Mylyn. It should be Window -> Show View -> Other... -> Task List.

Besides, it's better has a bugzilla repository or others. It should be more useful for a team work. I like the function to record the spending time on a task. But I have no idea how to use it from those tutorial.

Maybe see next time, hope has the opportunity to learn more about it.For now, just stop here. :)

[PSP]Chapter 3

2010-07-24T09:06:00.000-07:00

Correlation should be greater than 0.7, then you can said the two things are high related. To prevent the data is too small, we need to evaluate another coefficient - significance.

Significance should be less than 0.05. The number is smaller, the opportunity of happened by random is smaller.

[Eclipse]Eclipse IDE Tutorial

2010-07-18T03:06:00.000-07:00

Eclipse IDE Tutorial

Create jar files
1. Select your project, right click on it and select "Export".
2. Select JAR file, select next.
3. Select your project and maintain the export destination and a name for the jar file.
4. Press finish
5. Open a command shell(ex: DOS command), then run java -classpath your.jar YourClassName

Using java libraries(jar)
1. Create a folder named lib
2. import your jar files,from the menu select File -> Import -> File system. Select your jar and select the folder lib as target.
3.Select your project, right mouse click and select properties.in the third row Java Build Path Under libraries select "Add JARs".

Show source code for jar
1. Open the Java Build Path page of a project (Projects > Properties > Java Build Path). On the Libraries page expand the library's node and select the Source attachment attribute and press Edit
2. In the Location path field, enter the path of an archive or a folder containing the source.

Add the Javadoc for a jar
1. Download the javadoc of the jar and put it somewhere in your filesystem.
2. Open the Java Build Path page of a project (Projects > Properties > Java Build Path). On the Libraries page expand the library's node and select the Javadoc location attribute and press Edit.

Problem View
Only show the problems of current project. Not show all problems.
1. open it via Windows -> Show View -> Problem
2. Select Configure Contents in the view's option menu.
3. Checked Error/Warnings on Project

Working Sets
It can help you to organize all of your projects!
1. To setup your working set select in the Package Explorer -> Show -> Working Sets.
2. Press New to create a new Working Set

Synchronize package explorer with code display
1. press Link with Editor button on the right top of Package Exploer

Code Templates
This is very useful. You can typed short words, then press Ctrl+Space to replace to the sentence you want.
1. select the menu Window->Preferences and Open Java -> Editor -> Templates
Note: Ctrl+Space always has been defined by other applications, especially for Asia people who using it to change language input method.We need to change the shortcut Ctrl+Space

Modify shortcut
Replace shortcut from Ctrl+Space to Ctrl+Enter
1. Select the menu Window->Preferences and Open General -> Keys
2. Using filter to type Content Assist to find Content Assist(type:Template Proposals)
3. In binding: field, press key Ctrl+Enter

Coming soon...
Mylyn Project

JFreeChart Project

Common useful Shortcut

Debugging

Stand alone Java Client

[C]如何列出一個字串所有的排列組合？

2010-05-31T07:50:00.000-07:00

#include
#include
#include "test.h"

#define LENGTH 3
char charArray[LENGTH+1];

void init(void)
{
int i;
for (i=0; i< LENGTH; i++)
{
//charArray[i] = 43+i;
charArray[i] = 65+i;
printf("%c ", charArray[i]);
}
charArray[LENGTH]='\0';
}

void printSerial(int len, char* sourceChar, char* prefixChar)
{
int i;

if (len >= 2)
{
//printf("AA=%s\n", sourceChar);
for (i=0; i < len; i++)
{
int pre_len = 0;
char* pcPrefix = NULL;
char* psrcArray = (char*)malloc(len);

if (prefixChar)
pre_len = strlen(prefixChar);
pcPrefix = (char*)malloc(pre_len+2);

if (prefixChar)
strcpy(pcPrefix, prefixChar);

pcPrefix[pre_len] = sourceChar[i];
pcPrefix[pre_len+1] = '\0';
// printf("%d=pcPrefix=%s\n",pre_len, pcPrefix);
int j, k=0;
for (j=0; j {
if (j!=i)
psrcArray[k++]=sourceChar[j];
}
psrcArray[len]='\0';
//printf("%d=%s=%s\n", len-1, psrcArray, pcPrefix);
printSerial(len-1, psrcArray, pcPrefix);

}
}
else
{
if (prefixChar != NULL)
printf("%s", prefixChar);
printf("%c ", *sourceChar);
}

if (sourceChar)
{
free(sourceChar);
sourceChar = NULL;
}

if (prefixChar)
{
free(prefixChar);
prefixChar = NULL;
}
}

int main()
{
char* psrcArray = NULL;
char* pcPrefix = NULL;

printf("test\n");
init();
printf("\n\n");

psrcArray = (char*)malloc(LENGTH+1);
//printf("c=%s\n", charArray);
if (psrcArray)
strcpy((char*)psrcArray, (const char*)charArray);
psrcArray[LENGTH]='\0';
//printf("p=%s\n", psrcArray);
printSerial(LENGTH, psrcArray, NULL);

printf("\n\n");
return 0;
}

[Eclipse]Refactor

2010-04-01T09:22:00.000-07:00

選單 [Refactor]->Extract Method...

1. 先選取一段想要變成function 的code，選取好之後，這個選單才會變成可以選取的狀態
2. 執行[Refactor]->Extract Method...
3. 跳出編輯視窗，填入檔名和其他屬性
4. Function就自動建好了，而且會把其他地方的相同的code，都用function取代了。

[Eclipse]Useful shortcut

2010-04-01T09:19:00.000-07:00

Ctrl-Shift-O
如果要老是記住哪一個class是在哪一個package裡？對記憶力可是一種考驗。
現在可以在寫code的時候，先不要管需要import哪些package？先專心把code寫完，然後只要按下Ctrl-Shift-O 之後，Eclipse就會自動把缺的package的部分補上來了。

Ctrl+Shif+P
首先將cursor移到一個括號上，按Ctrl+Shift+P可以在相對應的一組括號的上下括號跳來跳去。

[Ubuntu]How to fix the noise of PC speaker after shut down

2010-03-15T07:32:00.000-07:00

Turn off PC speaker

>sudo -s
>echo blacklist pcspkr >> /etc/modprobe.d/blacklist.conf
>exit

[Ubuntu]How to fix GRUB?

2010-03-04T08:30:00.000-08:00

link to

1. Using Ubuntu livdCD to boot up, open a terminal

type cmd: sudo grub

in grub>

[find the pwd of grub]
grub>find /boot/grub/stage1

[then record pwd]
grub>root (hd?,?)

[install grub to mbr]
grub>setup (hd0)

[Exit]
grub>quit

2. another solution:
Using Ubuntu LiveCD to boot up, in startup menu, select
"救援已損壞的系統(R)"
Then...
a) Detect keyboard layout? (You can select No to skip), then select "USA"
b) Select root file system. Don't worry. If you dont remeber which one? Guess the one that is not Windows Which almost be sda1. If you select wrong one, system will tell you. So, you can back to select another.
c) select "重新安裝GRUB開機程式"(Reinstall GRUB)
d) type (hd0) to install GRUB (Most people install in hd0, if you using USB disk, this may not be your answer)
e)Reboot

[Ubuntu]Fix wireless disconnect automatically problem

2010-02-27T08:46:00.000-08:00

My acer ASPIRE 4740G in Ubuntu 9.10 has wireless problem. It will disconnect automatically.

We can use
"sudo apt-get install wicd"
to install Wicd Network Manager to replace the default one to fix this problem.