2008-07-23

Lemma, Theorem, Proposition & Corollary

有幾個東西一直沒法弄清楚, 但是偶爾會遇到它們: Lemma, Theorem, Proposition & Corollary.
過去偷懶都沒理會, 這會兒從wiki汪洋中找到了些許線索, 摘要出來.

請注意, 這只是摘要出來, 比較詳細的資訊得再連過去看才會知道.

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Lemma
:

  • In mathematics, a lemma is a proven proposition which is used as a stepping stone to a larger result rather than as a statement in-and-of itself. --- from wiki.
  • A lemma is a "pre-theorem", a statement that forms part of the proof of a larger theorem. The distinction between theorems and lemmas is rather arbitrary, since one mathematician's major result is another's minor claim. Gauss's lemma and Zorn's lemma, for example, are interesting enough that some authors present the nominal lemma without going on to use it in the proof of a theorem. --- from wiki.

Theorem:

  • In mathematics, a theorem is a statement proven on the basis of previously accepted or established statements. In mathematical logic, theorems are modeled as formulas that can be derived according to the derivation rules of a fixed formal system. The proofs of theorems have two components, called the hypotheses and the conclusions. The proof of a mathematical theorem is a logical argument demonstrating that the conclusions are a necessary consequence of the hypotheses, in the sense that if the hypotheses are true then the conclusions must also be true, without any further assumptions. --- from wiki.

Proposition:

  • A proposition is a statement not associated with any particular theorem. This term sometimes connotes a statement with a simple proof. --- From wiki.
  • In philosophy and philosophical logic, a proposition is the content of an assertion. --- From wiki.
  • In philosophy and logic, proposition refers to either (a) the content or meaning of a meaningful declarative sentence or (b) the pattern of symbols, marks, or sounds that make up a meaningful declarative sentence. Propositions in either case are intended to be truth-bearers, that is, they are either true or false.
  • The existence of propositions in the former sense, as well as the existence of "meanings", is disputed. Where the concept of a "meaning" is admitted, its nature is controversial. In earlier texts writers have not always made it sufficiently clear whether they are using the term proposition in sense of the words or the "meaning" expressed by the words. To avoid the controversies and ontological implications, the term sentence is often now used instead of proposition or statement to refer to just those strings of symbols that are truth-bearers, being either true or false under an interpretation.
  • In mathematics, the word "proposition" is often used as a synonym for "theorem". --- From wiki.


Corollary:

  • A corollary is a statement which follows readily from a previously proven statement. In mathematics a corollary typically follows a theorem. Proposition A is a corollary of proposition B if A can readily be deduced from B, but the meaning of readily varies depending upon the author and context. The importance of the corollary is often considered secondary to that of the initial theorem; A is unlikely to be termed a corollary if its mathematical consequences are as significant as those of B. Sometimes a corollary has a proof that explains the derivation. --- From wiki.

最恐怖的兩種人

Theorem : 存在最恐怖的兩種人 = 窮人瘋子


[Proof]

引用俗話:

$ 窮凶極惡

$ 瘋狗亂咬人


Note: The theorem is not implied for all people, but for some.

企業採用開放源碼軟體的安全隱憂



摘:

安全業者:企業採用開放源碼軟體要注意安全隱憂
文/陳曉莉 (編譯) 2008-07-22

被檢驗的11種開放源碼產品,發現總計有2.2萬的Cross-Site Scripting漏洞,以及1.5萬的SQL Injection漏洞。

軟體安全公司Fortify在周一(7/21)發表其開放源碼安全研究報告指出,被企業廣泛採用的開放源碼套裝軟體讓使用者曝露在重大且不必要的營運風險中。

Fortify與應用程式安全顧問Larry Suto共同檢驗了11種最普及的Java開放源碼套裝產品,並評估開放源碼社群提供給使用者的安全意見,以及測試其安全開發程序,包括與開發人員互動以 及檢視相關安全策略的相關文件,以及利用Fortify的安全分析工具偵測這些產品不同版本的安全性,並在特定程式碼區域執行手動偵測。

被檢驗的11種開放源碼產品分別是關聯性資料庫Derby、物件關係對應工具Hibernate、CRM網站應用程式Hipergate、電子商務網站應 用程式OFBiz、內容管理OpenCMS、網站應用程式架構Struts,以及涵蓋Geronimo、JBoss、JOnAS、Resin及 Tomcat等五種應用程式伺服器等。

Fortify利用Java Open Review(JOR)偵測上述產品不同版本進行安全漏洞檢視,發現總計有2.2萬的跨站攻擊漏洞(Cross-Site Scripting)以及1.5萬的資料隱碼漏洞(SQL Injection),此外,Fortify亦發現許多開發人員因為沒有採用安全開發周期的相關工具,導致錯失偵測及修補這些安全漏洞的關鍵機會。

該份報告揭露了上述產品的漏洞密度,顯示漏洞密度最底的前五項產品依序是JBoss、Hibernate、Ofbiz、Strusts及Geronimo,而漏洞密度最高的則是Hibernate。

......等等.

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有許多資訊相關的朋友們似乎都有一種很有趣的情節 --- 自由軟體(Open Source Softeware, OSS)偏好.
有些甚至會嚴重到, 似乎使用了OSS就油然而生出一種莫名其妙的卓越感,
我一直沒有辦法猜測, 感覺出這卓越感跟OSS有甚麼關係/連結?

OSS, 很棒, 這是無庸置疑的, 尤其在這全球不景氣的今天(尤其是我個人),
但是, 若排除了價格上的考量, OSS存在著一些嚴重的問題, 尤其是安全問題(Security), 效能(Efficiency), and 整合性(Integration).

這篇報導所瞄準的就是Security, 而疏忽Security的企業卻往往遭遇重大的損失, 若將這樣的損失聯結到企業財務, 似乎也是變相地增加了使用OSS的成本.

因此, 是否使用OSS一直都是個有趣的蹺蹺板問題,
答案是???

我的建議是:
"只要你行, 你敢用, OSS將會是你最好的選擇 !!~"

2008-07-14

回應: 討厭貧窮




痛恨貧窮, 所以我有動力.
這不是仇恨? 這是原力!

誰讓我們誕生在這世界的時候剛剛好落在這貧富的機率裡,
這是上天設定的
在這生命的遊戲中, 慶幸著自己還有一點思想, 活動也正常些,
遊戲得自己玩

就這一次機會 沒有重來
無法按Reset鍵, 但是可以關Power

嚴謹踏出每一步
This a WAR

我要玩得 最精采
我要玩得 全破關
我要玩得 不遺憾

Come~
Play together !!

21





決勝21點, 描述著一群MIT學生憑藉著其優異的數學天賦在LasVegas挑戰賭博遊戲-21點(Royal Match 21).

說是賭博?
轉個角度, 這本來就是一個充滿數學機率的遊戲.
MIT的天才也是人, 人總會希望升官發財, 擁有上天賜與的恩惠為什麼不用?
不過, 從電影中發現了這事實---人外有人, 天外有天.

這世界是很公平的, 不論天資如何, 一定得努力付出才可能會有收穫.
有人在想盡辦法犯罪, 取巧;
一定會存在有人拼死也要揪出罪犯, 防堵作弊.
Anything has its rules.

"Counting cards isn't illegal"---From "21".
"人為財死 鳥為時亡",
的確,算牌算算好玩就算了, 要去從中獲利真就是拼命, 好歹賭場可是營利事業呢!!

我很喜歡劇中的一段話:

Always account for valuable changes --- 有價值的改變總要付出代價

如果我有如電影中MIT天才們這樣的天賦,
我會怎麼運用這機智呢?

2008-07-11

第一次 我做到了

今天是重要的一天, 這一年帶的郭漢輝學弟今天口試通過了, 取得了畢業資格
這也是第一次完整地指導完碩士論文,
從指定題目 "Applying SHA-HCLY Evolution Criterion to Improve SHA-256 Security using Genetic Algorithm",
引導分析題目, 討論與最後的修正等等....
直到今天確認學弟完成了這項研究站上口試的講台, 成功地取得了口試委員一致好評.


葉老師, 謝謝您, 或許這就是您一直要教我的,
今天 我做到了, 謝謝您.


當然, 這只是第一步
持之以恆, 再出發.

2008-07-09

請記得你對我的承諾

今天接到電話被告知更改成績的公文通過了


那一天 你哭啼啼地透過系辦打給我
述說著你是多麼地努力申請轉系 多麼認真地學習企圖準時畢業參加八月的國家考試


可是每當我唸及你的名字 總是沒有人應答
一念之差 導致前功盡棄


或許是我人好
堅持著快樂的課 本該是快樂的
卻失去了你對我的尊重


遊戲 是有規則的 不是這樣玩的



封封Email從抱怨, 說理到認錯, 後悔
敲開了我鐵石心腸
一切的利弊得失放在天平的兩端
我思索著...


讓一個青年擁有希望是最大的收穫


第一次
上呈公文要求更改已送出的成績 為你



請務必記得你對我的承諾:


"一定要多多關懷與幫助需要幫助的人
所為之任何決定將關乎當事人之ㄧ生, 更應小心謹慎, 不容一絲差錯
"

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