Suppose Charlie had installed key logger software on all company computer systems and had made a copy of Peter’s encryption key. Suppose that Charlie had this done without policy authority and without anyone’s knowledge, including Peter’s. Would the use of such a tool be an ethical violation on Charlie’s part? Is it illegal? Suppose that Charlie had implemented the key logger with the knowledge and approval of senior company executives, and that every employee had signed a release that acknowledged the company can record all information entered on company systems. Two days after Peter’s call, Charlie calls back to give Peter his key: "We got lucky and cracked it early." Charlie says this to preserve Peter’s illusion of privacy. Is such a "little white lie" an ethical action on Charlie’s part?

Some of your friends have gotten into the burgeoning field of time-series data mining, in which one looks for patterns in sequences of events that occur over time. purchases at stock exchanges"what's being bought" are one source of data with a natural ordering in time. given a long sequence s of such events, your friends want an efficient way to detect certain "patterns" in them"for example, they may want to know if the four events buy yahoo, buy ebay, buy yahoo, buy oracle occur in this sequence s, in order but not necessarily consecutively. they begin with a collection of possible events (e.g., the possible transactions) and a sequence s of n of these events. a given event may occur multiple times in s (e.g., yahoo stock may be bought many times in a single sequence s). we will say that a sequence s is a subsequence of s if there is a way to delete certain of the events from s so that the remaining events, in order, are equal to the sequence s . so, for example, the sequence of four events above is a subsequence of the sequence buy amazon, buy yahoo, buy ebay, buy yahoo, buy yahoo, buy oracle their goal is to be able to dream up short sequences and quickly detect whether they are subsequences of s. so this is the problem they pose to you: give an algorithm that takes two sequences of events"s of length m and s of length n, each possibly containing an event more than once"and decides in time o(m + n) whether s is a subsequence of s.

Representa os dados de um banco de dados como uma coleç? o de tabelas constituídas por um conjunto de atributos, que definem as propriedades ou características relevantes da entidade que representam. marque a alternativa que representa o modelo descrito no enunciado. escolha uma:

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