星期四, 11月 04, 2010

Conference and Journal


Association for Computing Machinery (ACM)

Precision and Recall

Definition:

  • Source = 被尋找的資料庫
  • Target = 在 Source 內 某一種同類型的資料
  • ALLFind = 找出來的所有資料
  • GoldenFind = AllFind 裡跟 Target Match 的資料
Precision = GoldenFind / AllFind
Recall = GoldenFind / Target


結論:
  • 跟 Source 多少一點關系都沒有。
  • 找資來的資料,命中越高越好,如果找錯......只影響Precision,但至少保住了 Recall。
  • 也就是說 Precison & Recall 都為1時最佳。.
  • Precision = 1 比 Recall =1 簡單.


Reference 2nd 提到一個有趣的比喻:
要「一言既出駟馬難追」的precision就要高,要「寧可錯殺一人也不願放過一百」的recall值就必須要高


Reference 1st 舉的例子
舉個例子:假設現在資料庫中有10000筆資料,和美食有關的文章有500篇。使用者在輸入美食的關鍵字後,回傳的文章有4000篇,其中有400篇是和美食有關的。Precision = 400 / 4000 = 10%
Recall = 400 / 500 = 80%

Reference:

星期三, 11月 03, 2010

Frequently asked questions about basic auth


http://httpd.apache.org/docs/1.3/howto/auth.html#basicfaq

Frequently asked questions about basic auth

The following questions tend to get asked very frequently with regard to basic authentication. It should be understood that basic authentication is very basic, and so is limited to the set of features that has been presented above. Most of the more interesting things that people tend to want, need to be implemented using some alternate authentication scheme.


How do I log out?



Since browsers first started implementing basic authentication, website administrators have wanted to know how to let the user log out. Since the browser caches the username and password with the authentication realm, as described earlier in this tutorial, this is not a function of the server configuration, but is a question of getting the browser to forget the credential information, so that the next time the resource is requested, the username and password must be supplied again. There are numerous situations in which this is desirable, such as when using a browser in a public location, and not wishing to leave the browser logged in, so that the next person can get into your bank account.

However, although this is perhaps the most frequently asked question about basic authentication, thus far none of the major browser manufacturers have seen this as being a desirable feature to put into their products.

Consequently, the answer to this question is, you can't. Sorry.



http://webcache.googleusercontent.com/search?q=cache:FUVgYEnqsuEJ:doc1.fehot.com/2/K/35akhAU.html+lighttpd+logout&cd=16&hl=zh-TW&ct=clnk&gl=tw&lr=lang_zh-CN|lang_zh-TW

星期二, 11月 02, 2010


Install Instruction:
  • mkdir obj
  • cd obj
  • ../configure
  • gmake
  • gmake install

fix src/sysc/utils/sc_utils_ids.cpp
+#include "/usr/include/boost/cstdlib.hpp"
+#include
#include "sysc/utils/sc_report.h"
+using namespace std;