Computer Viruses :: essays research papers

Computer Viruses Explain the difference between viruses, worms and Trojan horses in the context of computer and data security. Discuss the measures that need to be taken in order to maintain security. There is a type of computer program that is designed and written to destroy, alter or damage data stored on computers without your knowledge or permission. These are some of the problems that these programs cause ? Your computer displays annoying messages ? Your computer develops strange visual and sound effects ? Files on your computer mysteriously disappear ? Your computer starts working very slowly ? Your computer reboots unexpectedly These programs are typically referred to as viruses although technically the computing term virus actually refers to a specific type of pest program. Other types are called Trojan horses and worms. The difference between these pest programs is how they behave when attacking a computer system and I am going to look at each type individually to explain the difference starting with viruses. A computer virus is a program that is designed to replicate and spread itself on its own, preferably without anybody knowing it exists. They spread by attaching themselves to other programs (such as your word processing or spreadsheet programs). Then when a file with a virus attached to it is executed the virus will also be executed. Viruses can also attach themselves to system files the computer uses every time it is switched on, these are called boot sector viruses, and can cause persistent and widespread disruption to the computer. Viruses can also infest documents such as those created with a word processor. Infested documents are stored with a list of instructions called a macro, which is essentially a mini program. Then when the document is viewed the macro is activated. These viruses are called macro viruses and actually account for 67.5% of all virus damage. Worms are very similar to viruses but are technically different in the way that they replicate and spread through the system. The difference is that programs or files don’t need to be run in order to activate the spreading of a worm. Because of this worms can be very dangerous when released on to computer networks. The Internet Worm was released on to the Internet on the 2nd November 1988 spread to over 6,000 computers in less than a day. And the total monetary costs of this infection are estimated at about $98,000,000. Which proves how much damage can be done with a worm.

Estimating Risk and Return

1. â€Å"Why is expected return considered forward-looking? What are the challenges for practitioners to utilize expected return? † (Cornett, Adair, and Nofsinger, 2012, p. 246). Expected return is â€Å"forward-looking† in the sense that it represents the return investors expect to receive in the future as compensation for the market risk taken. The challenge is that practitioners cannot precisely know what the future holds and thus what the expected return should be. Thus, we create methods to estimate the expected return. 2. Describe how different allocations between the risk-free security and the market portfolio can achieve any level of market risk desired. † (Cornett, Adair, and Nofsinger, 2012, p. 246). An investor can allocate money between a risk-free security that has zero risk (? =0), and the market portfolio that has market risk (? =1). If 75% of the portfolio is invested in the market, then the portfolio will have a ? =0. 75. If only 25% is invested i n the market, then the portfolio will have a market risk of ? =0. 25. The first example (? =0. 75) might be taken by a less risk averse investor while the second example (? 0. 25) illustrates the portfolio of a more risk averse investor. By allocating the investment money between 0 and 100% into the market portfolio, an investor can achieve any level of market risk desired. 3. â€Å"Compute the expected return given these three economic states, their likelihoods, and the potential returns:† Economic StateProbabilityReturn Fast Growth0. 3040% Slow Growth0. 5010% Recession0. 20? 25% Expected return = 0. 3? 40% + 0. 5? 10% + 0. 2? -25% = 12% 4. â€Å"If the risk-free rate is 6 percent and the risk premium is 5 percent, what is the required return? † (Cornett, Adair, and Nofsinger, 2012, p. 47). Required return = 6% + 5% = 11% 5. â€Å"The average annual return on the Standard and Poor's 500 Index from 1986 to 1995 was 15. 8 percent. The average annual T-bill yield during the same period was 5. 6 percent. What was the market risk premium during these 10 years? † (Cornett, Adair, and Nofsinger, 2012, p. 247). Average market risk premium = 15. 8% ? 5. 6% = 10. 2% 6. â€Å"Hastings Entertainment has a beta of 0. 24. If the market return is expected to be 11 percent and the risk-free rate is 4 percent, what is Hastings' required return? † (Cornett, Adair, and Nofsinger, 2012, p. 247).Use the capital asset pricing model to calculate Hastings' required return. Hastings’ required return = 4% + 0. 24 ? (11% ? 4%) = 5. 68% 7. Calculate the beta of your portfolio, which comprises the following items: (a) Olympic Steel stock, which has a beta of 2. 9 and comprises 25 percent of your portfolio, (b) Rent-a-Center stock, which has a beta of 1. 5 and comprises 35 percent of your portfolio, and (c) Lincoln Electric stock, which has a beta of 0. 2 and comprises 40 percent of your portfolio. (Adapted from Cornett, Adair, and Nofsinger, p. 248. ) 0 . 25? 2. 9 + 0. 35? 1. 5 + 0. 40? 0. 2 = 1. 33

Essay about We Must Ban Therapeutic Human Cloning

The Senate is considering a proposal to outlaw human cloning. Two alternative proposals would ban only reproductive cloning, which would mean explicitly legalizing human cloning but not the implantation of a clone embryo into a womb. Pro-cloners are willing for the most part to outlaw reproductive cloning because it isnt safe, but they oppose a ban on cloning for research and experimentation--known as therapeutic cloning--arguing that such a cloning license is necessary to the development of future medical treatments for human ailments. This opposition to a ban on human therapeutic cloning is misinformed. The case against cloning, including therapeutic cloning, has mainly been argued on grounds of morality. Opponents†¦show more content†¦Not only is human cloning immoral but it may have negative utility--in other words, attempting to develop human cloning technologies for therapeutic use may drain resources and personnel from more useful and practical therapies. To understand why therapeutic cloning fails the utility test, we must take a quick look at the significant difficulties facing embryonic stem cell research. Embryonic stem cell researchers hope to create medical treatments that would use undifferentiated cells--known generically as stem cells--extracted from 5-to-7-day-old embryos known as blastocysts. During natural gestation, these stem cells eventually differentiate, that is, they transform into bone, neurons, muscle, organs, blood--indeed, all of the more than 200 different tissue types in the body. Researchers hope to learn how to harness this ability by extracting stem cells from embryos, transforming them into specific tissues, and then injecting the tissues into patients to treat medical ailments. In their enthusiasm for embryonic stem cells--and in an effort to assure ample funding for the research--some advocates have all but promised that such therapies are just around the corner. But that isnt even close to being true. Writing in the scientific research journal Stem Cells, editor in chief (and advocate of embryonic stem cell research) Curt I. Civin admitted that scientists have exaggerated the immediacy of the prospects of clinical therapiesShow MoreRelatedThe Debate Over Human Cloning Essay1526 Words   |  7 Pages Human cloning, an unknown wonder to the universe the world has yet to unfold. The idea of cloning can be a dream to some and others not so much, there’s just endless possibilities when it comes to cloning. With the thought of cloning humans comes reality and other things that can cause issues or keep the experiment stagnant. â€Å"Reality† includes the process of cloning humans, types of cloning, products of cloning, cost, and also ethical issues. Besides the issues and reality part of cloning, thisRead More Immorality of Human Cloning Essay1550 Words   |  7 Pages While human cloning has been a matter of science fiction for centuries, the prospect that it could actua lly happen is a recent development. On February 23, 1997, the birth of the first cloned sheep, Dolly, was announced. Since then, it seems that science has progressed faster than moral understanding. Each breakthrough in genetics presents us with both a promise and a dilemma. The promise is that we may soon be able to treat and prevent diseases such as cancer and Parkinson’s. The dilemma is thatRead MoreShould Cloning Be Allowed?872 Words   |  4 Pages Though many have agreed that cloning should not be further researched there are still those who believe otherwise. Why exactly do people believe that research on human cloning should be allowed? 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It seems that every day scientists come up with some new, perhaps even controversial, and exciting ways to improve the quality of life. These new technologies affect every aspect of life, as we know it. One such technology is the research being done in the area of cloning. Cloning is the production of one or more cells, individualRead MoreCloning, Pros and Cons Essay2998 Words   |  12 Pagescontinue to get worse. They may be waiting a year or longer. Is there another way to speed up the waiting process? Cloning as a Possibility? These situations and many others have brought up the topic of cloning. Cloning refers to any process that results in the creation of an identical or almost identical genetic copy of a molecule, cell, or individual plant, animal, or human (Wilson, 2002). Recently, it is being heavily researched for its potential uses. Some difficult questions arise with