資訊科學 (Information Science)：從五個面向來看

這是作者 David G. Luenberger 在 Stanford University 教課所開發的教科書 (註 1)，Luenberger 教授寫了幾本經典之作，例如 Linear and Nonlinear Programming、Optimization by Vector Space Methods、Investment Science。維持其一貫的風格，這本書清楚地使用五個角度 (Entropy, Economics, Encryption, Extraction, and Emission) 來分析與了解資訊科學，四個主題 (average performance, optimality, complexity, structure) 則貫穿其中。 

書商的介紹詞如下

"From cell phones to Web portals, advances in information and communications technology have thrust society into an information age that is far-reaching, fast-moving, increasingly complex, and yet essential to modern life. Now, renowned scholar and author David Luenberger has produced Information Science, a text that distills and explains the most important concepts and insights at the core of this ongoing revolution. The book represents the material used in a widely acclaimed course offered at Stanford University.

Drawing concepts from each of the constituent subfields that collectively comprise information science, Luenberger builds his book around the five "E's" of information: Entropy, Economics, Encryption, Extraction, and Emission. Each area directly impacts modern information products, services, and technology--everything from word processors to digital cash, database systems to decision making, marketing strategy to spread spectrum communication.

To study these principles is to learn how English text, music, and pictures can be compressed, how it is possible to construct a digital signature that cannot simply be copied, how beautiful photographs can be sent from distant planets with a tiny battery, how communication networks expand, and how producers of information products can make a profit under difficult market conditions."

(註 1) David G. Luenberger, Information Science, Princeton University Press, 2006. 完成時作者已經 69 歲，在美國很常見。參考先前 blog 的 Dr. Tapley。

美國畢業後返台的理由：朋友的提問和我的回答

留在美國的可能理由：

• 薪水比台灣高，參考企管碩士 (MBA) 的例子。不過，個人所得稅和某些服務業費用較高，所以做薪資比較不太客觀 (註 1)。
• 美國匯集了全球人才，工作環境與內容比較挑戰 (註 2)。
• 子女的教育問題。
• 強大的美國，穩定的生活和政治環境 (註 3)。

當你使用 Google 搜尋網頁時，結果是如何排序的？

解聯立方程式 A x = x 

當你搜尋網頁時，為什麼有的在前，有的在後？Google 創辦人的點子如下 (註 1)，如果越多的網頁連結到一個網頁，代表該網頁越重要，將出現在越前面的位置。 

當供應商變成競爭對手時：Apple 和 HTC 的例子

華爾街日報報導 (Apple Finds It Difficult to Divorce Samsung )，因為三星和 Apple 在手機市場的競爭，Apple 開始將 iPads 和 iPhones 的面板和記憶體訂單轉到日商，2014 年也將處理器部份訂單交由台積電生產。文中報導，2012 年的處理器下單金額約 50 億美元：

Apple's component orders from Samsung were set to hit around $10 billion last year, says Mark Newman, an analyst at Sanford Bernstein in Hong Kong. That represents a significant chunk of the 67.89 trillion won ($59.13 billion) Samsung posted in sales from its component business, which includes chips and displays. The Apple processor, where Samsung is currently the sole supplier, accounted for $5 billion of purchases in 2012, he estimates.

HTC 的例子和 Apple 類似，當其手機熱賣時（HTC learns lesson from Samsung display supply row)，三星就拒絕供應 AMOLED 面板：

But once the HTC Desire was welcomed by global consumers and telecom operators at the time, Samsung "strategically declined" to supply its AMOLED displays to the smartphone maker, Tong said at a local forum on mobile broadband.

"We found that key component supply can be used as a competitive weapon," he said.

後來，HTC 就找友達供應。