...Running Head: THERAC-25 CASE STUDY Therac-25 Case Study Therac-25 Case Study Therac-25 is a radiation therapy machine that was used for treating patients with cancer. The machine and its predecessors, Therac-6 and Therac-20, was a product from the collaboration of Atomic Energy of Canada Limited (AECL) and a French company called CGR (Leveson, n.d., p. 2). It is this machine that will cause other developers and manufacturers to rethink how to develop machines that will impact people’s lives. The Therac-25 was involved in six massive overdoses that cost three people’s lives, while the machine gave the operator error messages or a message that states that no dose was given (Baase, 2008, p. 425). After the first accident, some users became skeptical of the safety of the device. Yet, the manufacturer turned a blind eye on the matter. They responded to the incident that they have fixed the problem. In the following months, five more accidents occurred. In each incident, the manufacturer, the computer programmer, and the clinic/hospital using the Therac-25 have some responsibilities and flaws that need to be addressed. The Problems Manufacturer What would be the first thing that a manufacturer needs to do when they have an incident with one of their products? It should be the recall of that product, in this case the Therac-25. The Therac-25 can help a person ailing with cancer with its beam but the beam itself would be too harmful to the patient. Any medical equipment...
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..................................... 2 A Sample Design...................................................................................................................................3 Deciding if Frame Relay is Right for the Network.................................................................................... 4 Advantages of Frame Relay...................................................................................................................4 Disadvantages of Frame Relay.............................................................................................................. 5 Alternatives to Frame Relay.................................................................................................................. 6 X.25.................................................................................................................................................. 6...
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...What's the best WAN connection type for you? 14Comments more + * Email * Print * Add to Favorites * Del.icio.us * Digg * Hacker News * LinkedIn * Reddit * Technorati By Warren Heaton August 16, 2000, 7:00am PDT When designing a wide area network (WAN), one of the most challenging issues is choosing the correct connection type. You need to consider several factors before implementation can begin—and a solid understanding of all the connection types is critical to making the right choice. Most carriers offer three connection types: 1. Circuit-switched connections 2. Packet-switched or cell-switched connections 3. Dedicated connections Each type of connection has its advantages and disadvantages. This article will summarize what each connection type has to offer, with consideration given to bandwidth, availability, cost, and ease of management. Circuit-switched connections Circuit-switched connections are currently the most popular type of WAN connection. Circuit switching transmits data streams and datagrams across dedicated physical circuits. To provide asynchronous dial-in and ISDN services, the telephone companies use circuit switching. Asynchronous dial-in The public switched telephone network (PSTN) uses circuit-switched technology to provide asynchronous services (otherwise known as normal telephone service). Asynchronous dial-in connections offer a low-bandwidth, easily managed, cost-effective solution that...
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...Unit 7 Assignments Multiple Choice: 1. A 2. A,B 3. A,B 4. B 5. D 6. B,D 7. A 8. A 9. C 10. D 11. C 12. C 13. B,C 14. C 15. B,C 16. B,D 17. C 18. D 19. C,D 20. B,C Key Terms: Switched circuit- A circuit created by the phone company in reaction to signaling (the user tapping telephone keys or a modem sending in the same digits), with the telco tearing down the circuit when the user is finished. Dedicated circuit- An electrical circuit created by a telco on behalf of a customer, with the circuit staying up all the time, dedicated for use by the one customer that ordered the circuit. Also known as a leased line, leased circuit, and point-to-point line Circuit switching- The overall process by which a series of telco devices called circuit switches connect a circuit from one customer device to the other, with the device’s logic taking incoming bits on one segment in the link and forwarding those bits out the matching outgoing segment, without storing the bits Packet switching- the process of forwarding customer data in a WAN by looking at the header of the messages sent into the WAN by the customer and making a per-message decision as to where to forward each message. Leased line- A physical link between two locations, provided by a telco, that allows two-way communication between sites. Because the customer does not own the physical line between sites, but rather pays a monthly fee for the service...
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...Jun-10 Nov-10 Sep-11 Feb-12 Apr-11 Jul-12 Dec-12 IN FOCUS February 21, 2013 Economics Why Gold’s Lustre Will Fade by Avery Shenfeld and Emanuella Enenajor Avery Shenfeld It’s been a glorious run. The gold price climbed by nearly 500% from 2002 to Chart 1 Global Inflation Fears Overrated (416) 594-7356 avery.shenfeld@cibc.ca present, making it one of the best performing asset classes. But already, many of the forces 8% Inflation Rate* Benjamin Tal (416) 956-3698 benjamin.tal@cibc.ca Peter Buchanan (416) 594-7354 peter.buchanan@cibc.ca Warren Lovely that made the yellow metal so attractive look to be turning over, and expectations for other supportive factors are overdone. Gold will have its day in the sun at other points down the road, but the clouds on the horizon could portend still lower gold prices over the next couple of years. 6% 4% 2% 0% BRIC G7 + Eurozone (416) 594-8041 warren.lovely@cibc.ca Emanuella Enenajor (416) 956-6527 emanuella.enenajor@cibc.ca Andrew Grantham (416) 956-3219 andrew.grantham@cibc.ca “text text text” The Money Myth Gold’s allure has typically rested on two concerns about the alternative asset: money. Either inflation alone, or in concert with a steep currency depreciation, is seen as a reason for holding gold rather than the most prominent alternative, the US dollar. In terms of current inflation, it’s hard to see what anyone would be worried about...
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...HE WHO LASTS LAST LASTS BEST? As discussed in the exercise, the improvemnets in technologies and business processes at one side expands the market but on the other hand also brings decay for several players in the market. With the decay deciding the exit / collude / compete strategy for any particular industry player becomes a crucial factor. In this exercise we have two players – David & Goliath in the slingshot industry, which is one of the decaying industry. Based on theprevious quarter results of each other, both the players decide either to stay or to exit in the coming quarter without knowing each other’s choice. Since we know that slingshot industry will extinct by 1991, we need to come up with the exit strategy for the existing two firms. To analyze a possible exit point we have used the „Elimination of Dominated Strategy“ with following steps: 1. Drawing the sequential decision tree for David & Goliath from 1988 to 1991 2. Working from backwards to eliminate non-credible options at each point 3. Finding a possible set of best strategy at each level 4. Taking the chosen set of strategy above to the previous level 5. Repeating steps 2 to 4 till we locate a possible exit point for one of the players | David | Qty | Revenue | Goliath | Qty | Revenue | David & | Qty | Revenue-D | Revenue - G | | Alone | | | Alone | | | Goliath | | | | | | | | | | | | | | | Jan. 1988 | 3 | 1 | 3 | 2 | 2 | 4 | 0.5 |...
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...Transmission Control Protocols or TCP is among the key methods utilized in Internet Protocol Suites. TCP has got two end systems, a web browser and a web server from which it operates. TCP provides delivery of a stream of bytes from a program on one computer system to another. Internet Protocols operate at a lower level compared to TCP. An IP is used for data transmission across a packet switched internetwork. In X on and X off signals, the X means transmitter. These types of signals are used to manage the movement of data between computer systems on an asynchronous serial connection. In X on, the bit configuration is the keyboard blend of Ctrl-Q and the Ctrl-S combination is for X off. There are two kinds of transmissions, parallel as well as serial. In parallel transmissions, several bits are transmitted on the same radio path at the same time, and are synchronized to a clock. Parallel devices can transfer much more data at a time because they have bigger data buses, instead of the one wire used in serial transmissions. Kudler Fine Foods Network Overview Introduction One of the considered “best fine food stores” around is the Kudler FineFoods. However, Kudler is in serious need of a network infrastructure upgradeof their old one. To introduce the latest technologies in data collection; company communication; and information protection while providing the bestdata speeds and network access; are the main goals of the enterprisenetwork. This huge step is significant as this...
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...Bibliography * An Ice Cream Machine That Measures Smiles, CBS News, 25 June 2010 http://www.cbsnews.com/stories/2010/06/25/tech/main6616630.shtml * BBC News. "Procter and Gamble issues second profits warning." BBC . N.p., n.d. Web. 17 Oct. 2012. <http://www.bbc.co.uk/news/business-18522106>. * Criticism in India over skin-whitening trend, The Daily Telegraph 10 Jul 2008 <http://www.telegraph.co.uk/news/worldnews/asia/india/2279971/Criticism-in-India-over-skin-whitening-trend.html> * Dove Reference: <http://www.telegraph.co.uk/news/worldnews/asia/india/2279971/Criticism-in-India-over-skin-whitening-trend.html> * Eluta.ca. "Procter & Gamble Inc. ." eluta.ca. N.p., n.d. Web. 17 Oct. 2012. <http://www.eluta.ca/top-employer-procter-%26-gamble>. * Mother Nature Network. "Procter & Gamble and the environment | MNN - Mother Nature Network." Mother Nature Network. N.p., n.d. Web. 16 Oct. 2012. <http://www.mnn.com/money/sustainable-business-practices/stories/procter-gamble-and-the-environment>. * Palm Oil Issue - "Ape protest at Unilever factory" BBC, Tuesday, 22 April 2008 <http://news.bbc.co.uk/2/hi/uk_news/england/7358071.stm> * P&G. "2011 Annual Report." P&G. N.p., n.d. Web. 15 Oct. 2012. <www.pg.com/en_US/downloads/sustainability/reports/PG_2011_Sustainability_Report.pdf>. * P&G. "Purpose & People." P&G.com. N.p., n.d. Web. 16 Oct. 2012. <http://www...
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...Chapter 1 Data Communications Introduction 1 Chapter Objectives: Defined data communications Introduced data communications needs Communications model Overview of networks Introduce Internet 2 Data, Data Communication Data is an entity that convey some meaning based on some mutually agreed upon rules/conventions between a sender and a receiver. Data Communication deals with the transmission of signals in a reliable and efficient manner 3 Data Communication Topics covered include: Signal Transmission Transmission Media Signal Encoding Interfacing Data link control Multiplexing 4 Computer Science and Data Communications Merger In 1970s and 1980s The computer communications revolution has produced several remarkable facts. There is no fundamental difference between data processing (computers) and data communications (transmission and switching equipment). There is no fundamental difference among data, voice, and video communications. The distinction among single processor computer, multiprocessor computer, local network, metropolitan network, and long-haul network has blurred. 5 Today’s Trends Three different forces have consistently driven the architecture and evolution of data communications and networking facilities: Traffic growth Development of new services Advances in technology 6 Communication Traffic Both local (within a building or building complex) and Long distance having transmission of Voice, video and data The increased emphasis on office automation...
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...Fine Foods Integrative Network Design Project Kudler Fine Foods has requested for an overhaul of its computer network infrastructure to a more efficient networking system to provide broader network communications to other stores. The service request calls for changing the administration network to a WLAN, design a WAN to link all of it stores, and add VoIP to all stores. Kudler Fine Foods need to communicate to its entire store locations so a Wide Area Network (WAN) needs to be designed with keeping the network within its budget and high end service in mind. To meet this requirement Kudler Fine Foods will purchase a Frame Relay service from its telecom provider. There are other methods for designing WANs then using a Frame Relay like X.25 and ATM, however, my initial choice was based by performance measures, cost, and network expansion to Kudler Fine Foods network requirements. All of its store locations will be using full and fractional T-1 lines which its headquarters location will use full T-1 while other locations will use fractional. In addition, the equipment used in the WAN design will be Data Terminal Equipment (DTE) and routers with plug-in WAN Interface Card (WIC) that will provide and efficient communication link to all of its stores. Further, a dual-hub network topology will be the used to expand the network as well as reduce the number of Permanent Virtual Circuit (PVC) connections while still maintaining redundant connections for faults that occur. A dual-hub...
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...Некоммерческое Акционерное Общество АЛМАТИНСКИЙ УНИВЕРСИТЕТ ЭНЕРГЕТИКИ И СВЯЗИ Кафедра иностранных языков СЕМЕСТРОВАЯ РАБОТА №2 По дисциплине: «Английский язык» Технический перевод Специальность: 6M071900 – Радиотехника электроника и телекоммуникации Выполнила: Шаймагамбетова А.А. № з. к.: 12М3068 Группа СССп-12-01 Проверила: Бухина С.Б. __________________________ «_____»_________________________2012 год Алматы 2012 СОДЕРЖАНИЕ 1 Annotation 3 2 PACKET SWITCHING 3 3 КОММУТАЦИЯ ПАКЕТОВ 6 ТЕРМИНОЛОГИЧЕСКИЙ СЛОВАРЬ 10 СПИСОК ЛИТЕРАТУРЫ 11 Annotation This text describes packet switching, its modes and history. The main topic of this text is how packet switching works. Packet switching is a digital networking communications method that groups all transmitted data – regardless of content, type, or structure – into suitably sized blocks, called packets. The concept of switching small blocks of data was first explored by Paul Baran in the early 1960s. Independently, Donald Davies at the National Physical Laboratory (NPL) in the UK had developed the same ideas a few years. Two major packet switching modes exist; (1) connectionless packet switching, also known as datagram switching...
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...MIS589_WK4_Mini-case-MegaCorp_PC Questions: MegaCorp is a large manufacturing firm that operates 5 factories in Dallas, 4 factories in Los Angeles, and 5 factories in Albany, New York. It operates a tightly connected order management system that coordinates orders, raw materials, and inventory across all 14 factories. What type of WAN architecture and WAN service would you recommend? Why? Recommendations: When designing a WAN, numerous factors must be considered. Organizations attempting to connect multiple factories or offices and remote personnel must take into account a number of variables that will impact overall costs and network functionality. When designing and implementing wide area networks (WANs) that integrate voice, video, asynchronous and synchronous data and LAN traffic, all aspects of the organization's goals must be factored into the WAN design. Specific attention must also be paid to upfront cost, line charges, network throughput, security, and the inclusion of application and emerging technologies. Requirements will change, depending on whether you are creating a new network, modifying an existing network or integrating an existing network with other networks. Assuming there is an existing network, the next step is to inventory the network, identifying the circuits and all associated hardware (routers, firewalls) and software supporting the network, and summarizing all network-related expenses. Finally, access to network performance statistics (such as throughput...
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...Protocol Choices April 28, 2013 Team 5 (John Castro, Ruben Barragan, Teri Jordin, Saul Nolasco) There are many choices to make when you are deciding how your network will communicate with each other. There are a lot of protocols to take into consideration that will help make this possible. We have decided that for our WAN protocols, we will go with using frame relay. We will explain why we have chosen to go with frame relay, but first we will explain why the other choices are did not fit our needs at ABC company. HDLC is one of the protocols that we had a hard time coming to a conclusion with. It is a very good protocol and could have done well for the ABC Company but there are a few things that come with HDLC that made us come to the final decision of why not to use it. First of all, HDLC is a type of point-to-point protocol, which means that it costs a lot more money to have. The reason why it will cost more is because this means that every different branch has to be connected to each other. Almost like in a mesh topology form and that is wasting a lot of money there. PPP is the other protocol that we had a hard time deciding whether or not we were going to use over the other two. PPP is another point-to-point protocol that networks use in order to be able to communicate with each other. As a matter of fact, PPP is an acronym for point-to-point protocol. Once again, we have decided that PPP will waste too much money because every branch will need to...
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...GREG GLASSMAN BIOGRAPHY 1974 – 1989 1995 “ As an 18 year-old college student, Coach Glassman took his first training job - coaching gymnastics at the Pasadena, CA Y.W.C.A. Coach Glassman trained a celebrity/athlete clientele in dozens of Southern California gyms, finding success with an efficient, high intensity workout. While working with police officers, Glassman realized what bodybuilding and endurance programs were both lacking. Started pairing heavy “fundamental” movements (lifting) with sprints. Coach Glassman is hired to train the Santa Cruz, CA Police Department. The strength and value of CrossFit lies entirely within our total dominance of other athletes and this is a truth that cannot be divined through debate, only competition. “ 1974 “ “ We're changing the world. We're doing all the right things for all the right people for all the right reasons. And it's a load of fun. 1995 1995 CrossFit receives attention in radio and print for contributions to police fitness and athletic dominance. 2001 Glassman launches crossfit.com as an open source program, featuring his prescribed Workout of the Day, a library of workout and exercise demo videos, and an active discussion forum. “ 2003 2005 – 2009 It can kill you. I've always been completely honest about that. “ Coach Glassman opens the first CrossFit gym in Santa Cruz, CA. CrossFit begins affiliation program: 18 affiliates are created by 2005. Affiliate growth...
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...The four major protocols for circuit switching and packet switching are as follows: • X.25 • Frame Relay • ATM or Asynchronous Transfer Mode protocol • TCP/IP X.25 is probably one of the very first of packet switching protocols. It performs really well, especially considering how long it has been around. X.25 uses a virtual circuit approach, mainly using POTS or plain old telephone service lines, which are different from lines such as ISDN. The POTS lines are analog copper lines, so they can experience a lot of errors. But, once the lines have been connected, X.25 connections are really reliable. It's quite an efficient way to send packets across various data networks, with the X.25 protocol redundant error checking at each of the nodes. Frame relay is different because it doesn't require the need for analog wires or overhead wires like X.25 does. But this means that Frame Relay doesn't have the added framing and processing that X.25 has that provide guaranteed data transfers. It also doesn't have link to link reliability. So if a frame is corrupted, it is discarded, which is different than TCP as it detects and recovers any and all discarded frames. Asynchronous Transfer Mode protocol is used with either a coaxial cable, twisted pair, or fiber. ATM also takes advantage of a 53-btye cell, having 48 application bytes and 5 bytes are allocated for the ATM headers. ATM shows a lot more enhancements over Frame Relay...
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