不能說的秘密---網路釣魚防治技術
在數位化的今日，由於網際網路的技術蓬勃發展，網際網路變得更容易使用及具高度的親和性，使得網際網路的使用逐年成長。隨著越來越多人依賴網路進行交易，也衍生了層出不窮的網路詐騙問題。其中，網路釣魚就是一項著名的詐騙技術：詐騙者透過偽裝成知名企業的網站，藉此騙取使用者的個人私密資料。在本研究中，我們提出了一套植基於彩色視覺密碼學原理的網站驗證機制，使用者可以透過此機制，直接利用人類視覺的方式來驗證所連上的網站是否有問題，並在此機制之下，設計出另一套管理使用者密碼的方式，進而方便使用者不必費心的去記憶密碼。 Recently, as networks technology flourishes, Internet becomes easier and friendlier to use, and makes the usage of Internet grow up year after year. With more and more people relying on online transactions, it leads to endless network fraud issues. Among them, phishing is a well-known fraud technology to disguise the famous business website to get user’s private information by cheating. Therefore, in this study, an effective scheme based on color visual cryptography is proposed to test and verify the website. Through the proposed mechanism, users can check whether there is a problem website by using human vision directly. Furthermore, the proposed scheme also provides another way to manage user’s password effectively.
替機器人安排作業程序
編號1~mn 的mn 個物件已隨機置入m× n 階的矩陣中，另外有一行m 個空格的暫存區供物件暫存用。我們探討將這mn 個物件移至目標區並按照1,2,…, mn 的次序排列，所需的移動步數；每一步的移動中，只能移動每一行最頂層的物件到其他行(含暫存區)的最頂層或目標區。在這篇報告中，我們給出了一個適用於n ? m ?1時的移動方法，此方法在一般的情形下，所需的移動次數未必是最少；但是在最不利於移動的情形下，我們證明此方法所需的移動步數為最少。There are mn objects, numbered from 1 to mn, put on an m× n matrix randomly, and there is another column with m blank spaces for temporary storage purpose during moving. In each step of moving, we can only move the top object from one column to the top of another column or to the target pile. The total steps needed to move these mn objects to the target pile in increasing order from the bottom to the top is studied in this article. A general method for solving this problem when n ? m ?1 is given, and we prove that it provides an optimal solution in the worst cases. However, it may not always provide the minimal steps in all cases.
都是氣泡惹的禍
當輕敲啤酒杯時，會發覺酒杯發出之聲調隨氣泡漸漸消失而有所改變。為了解氣泡是如何影響頻率，我測試了幾種含氣泡之飲料，以探討當氣泡漸漸消失時，杯子發聲頻率之變化。實驗發現杯子內飲料之氣泡漸漸消失時，裝啤酒與可樂杯子的發聲頻率逐漸增高，然而裝沙士杯子的頻率卻逐漸降低。為解開此相互矛盾的現象，我設計了將液面上之泡沫及液面下之氣泡分開檢驗的實驗。實驗結果發現，液體中氣泡的存在會使杯子發聲頻率變高。而當液體表面受到擾動時，會降低杯子的發聲頻率。若液面上存在泡沫時，杯子的發聲頻率也會變低。這表示裝盛含氣泡飲料杯子音律之變化，須同時考量液內含泡量與液體表面之效應。此結果可以成功的解釋為何啤酒、可樂與沙士於氣泡漸漸消失時，杯子頻率會變高或變低的現象。Tapping the side of a glass of beer as the bubbles escape, one can find that the pitch will change. In order to know how the bubbles would influence the frequency, I survey the pitches of a wine glass with various drinks that would generate bubbles. As bubbles getting away from the glass, my experimental data shows that the frequencies of the tone did get higher when the glass contains beer and coke. However, I surprisingly find a different result when the same glass contains sarsaparilla. Hence I design a series of experiments to understand the possible mechanism. The data suggests that when the drinks contain bubbles in it, the frequencies of the tones will be higher. When the liquid surfaces were disturbed, the frequencies of the tones will become lower. If there were foams above the liquid surfaces, the frequencies of the tones will also be lower. This finding proposes that people needs to consider both the bubble bulk status and surface effects. The consequences of the competitions between these two effects can successfully explain how the tones are changed in the cases of beer or sarsaparilla or coke.