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Copyright ? 2014 Pearson Educationpublishing as Prentice Hall
Telecommunications, the Internet, and Wireless Technology
Chapter 7
Video cases:
Case 1: Telepresence Moves Out of the Boardrooom and Into the Field
Case 2: Unified Communications Systems: Virtual Collaboration with Lotus Sametime
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Management Information Systems, Global Edition
Chapter 7: Telecommunications, the Internet, and Wireless Technology
?Identify the principal components of telecommunications networks and key networking technologies.?Identify the different types of networks.
?Describe how the Internet and Internet technology work and how they support communication and e-business.?Describe the principal technologies and standards for wireless networking, communication, and Internet access.
?Describe radio frequency identification and wireless sensor networks and identify why these are valuable business technologies.
LEARNING OBJECTIVES
Management Information Systems, Global Edition
Chapter 7: Telecommunications, the Internet, and Wireless Technology
?Problem: Inefficient manual processes; large production environment
?Solutions: Track components in real time, optimize transportation, and expedite communication
–Wi-Fi networks –RFID technologies –Mobile handhelds
–
Material inventory tracking software
?Demonstrates use of technology in production and supply chain to increase efficiency and lower costs
RFID and Wireless Technology Speed Up Production at Continental Tires Management Information Systems, Global Edition
Chapter 7: Telecommunications, the Internet, and Wireless Technology
?Networking and Communication Trends
–Convergence:
?Telephone networks and computer networks
converging into single digital network using Internet standards
–Broadband:
?More than 68% U.S. Internet users have broadband access
–Broadband wireless:
?Voice, data communication are increasingly taking place over broadband wireless platforms
Telecommunications and Networking in Today’s Business World
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?Computer network
–Two or more connected computers –Major components in simple network
?Client and server computers ?Network interfaces (NICs)?Connection medium
?Network operating system ?
Hubs, switches, routers
–Software-defined networking (SDN)
?Functions of switches and routers managed by central program
Telecommunications and Networking in Today’s Business World 7.6
Copyright ? 2014 Pearson Education
Illustrated here is a very simple computer network, consisting of computers, a network operating system residing on a dedicated server computer, cabling (wiring) connecting the devices, network interface cards (NIC), switches, and a router.
Figure 7-1
Components of a Simple Computer Network
Management Information Systems, Global Edition
Chapter 7: Telecommunications, the Internet, and Wireless Technology
?Networks in large companies
–Hundreds of local area networks (LANs) linked to firmwide corporate network –Various powerful servers
?Web site
?Corporate intranet, extranet ?Backend systems
–Mobile wireless LANs (Wi-Fi networks)–Videoconferencing system –Telephone network –
Wireless cell phones
Telecommunications and Networking in Today ’s Business World Management Information Systems, Global Edition
Chapter 7: Telecommunications, the Internet, and Wireless Technology
Today ’s corporate network infrastructure is a collection of many different networks from the public switched telephone network, to the Internet, to corporate local area networks linking workgroups,
departments, or office floors.Figure 7-2
Corporate Network Infrastructure
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?Key digital networking technologies
–Client/server computing
?Distributed computing model
?Clients linked through network controlled by network server computer
?Server sets rules of communication for network and provides every client with an address so others can find it on the network
?Has largely replaced centralized mainframe computing ?The Internet: largest implementation of client/server computing
Telecommunications and Networking in Today ’s Business World 7.10
Copyright ? 2014 Pearson Education
?Key digital networking technologies (cont.)
–Packet switching
?Method of slicing digital messages into parcels (packets), sending packets along different
communication paths as they become available, and then reassembling packets at destination
?Previous circuit-switched networks required assembly of complete point-to-point circuit
?Packet switching more efficient use of network ’s communications capacity
Telecommunications and Networking in Today ’s Business World Management Information Systems, Global Edition
Chapter 7: Telecommunications, the Internet, and Wireless Technology
Data are grouped into small packets, which are transmitted independently over various communications channels and reassembled at their final destination.
Figure 7-3
Packet-Switched Networks and Packet Communications Management Information Systems, Global Edition
Chapter 7: Telecommunications, the Internet, and Wireless Technology
?Key digital networking technologies (cont.)
–TCP/IP and connectivity
?Protocols: rules that govern transmission of information between two points
?Transmission Control Protocol/Internet Protocol (TCP/IP)
–Common worldwide standard that is basis for Internet
?Department of Defense reference model for TCP/IP
–Four layers
?Application layer ?Transport layer ?Internet layer
?
Network interface layer
Telecommunications and Networking in Today ’s Business World
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This figure illustrates the four layers of the TCP/IP reference model for communications.Figure 7-4
The Transmission Control Protocol/Internet Protocol (TCP/IP) Reference Model
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?Signals: Digital versus analog
–Modem: translates digital signals into analog form (and vica versa)
?Types of networks
–Local-area networks (LANs)
?Ethernet
?Client/server vs. peer-to-peer
–Wide-area networks (WANs)
–Metropolitan-area networks (MANs)–Campus area networks (CANs)
Communications Networks
Management Information Systems, Global Edition
Chapter 7: Telecommunications, the Internet, and Wireless Technology
A modem is a device that translates digital signals into analog form (and vice versa) so that computers can transmit data over analog networks such as telephone and cable networks.
Figure 7-5
Functions of the Modem Management Information Systems, Global Edition
Chapter 7: Telecommunications, the Internet, and Wireless Technology
?Physical transmission media
–Twisted pair wire (CAT5) –Coaxial cable –Fiber optics cable
–
Wireless transmission media and devices
?Satellites
?Cellular systems
?Transmission speed
–Bits per second (bps)–Hertz
–Bandwidth
Communications Networks
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?The Internet
–World’s most extensive network –Internet service providers (ISPs)
?Provide connections
?Types of Internet connections –Dial-up: 56.6 Kbps
–Digital subscriber line (DSL/FIOS): 385 Kbps–40 Mbps
–Cable Internet connections: 1–50 Mbps –Satellite
–T1/T3 lines: 1.54–45 Mbps
The Global Internet 7.18
Copyright ? 2014 Pearson Education
?Internet addressing and architecture
–IP addresses
?The Domain name system (DNS)
–Converts IP addresses to domain names –Hierarchical structure –Top-level domains
?Internet architecture and governance
–No formal management: IAB, ICANN, W3C –The future Internet: IPv6 and Internet2
The Global Internet
Management Information Systems, Global Edition
Chapter 7: Telecommunications, the Internet, and Wireless Technology
The Domain Name System is a hierarchical system with a root domain, top-level domains, second-level domains, and host computers at the third level.Figure 7-6
The Domain Name System
Management Information Systems, Global Edition
Chapter 7: Telecommunications, the Internet, and Wireless Technology
The Internet backbone connects to regional networks, which in turn provide access to Internet service providers, large firms, and government institutions. Network access points (NAPs) and metropolitan area
exchanges (MAEs) are hubs where the backbone intersects regional and local networks and where backbone owners connect with one another.
Figure 7-7
Internet Network Architecture
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Read the Interactive Session and discuss the following questions
Interactive Session: Organizations –What is network neutrality? Why has the Internet operated under net neutrality up to this point in time?–Who ’s in favor of network neutrality? Who ’s opposed? Why?
–What would be the impacts on individual users, businesses, and government if Internet providers switched to a tiered service model?
–Are you in favor of legislation enforcing network neutrality? Why or why not?
The Battle over Net Neutrality
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?Internet services
–Chatting and instant messaging
–Electronic discussion groups / newsgroups –Telnet
–File Transfer Protocol (FTP)–World Wide Web
The Global Internet
Management Information Systems, Global Edition
Chapter 7: Telecommunications, the Internet, and Wireless Technology
Client computers running Web browser and other software can access an array of services on servers over the Internet. These services may all run on a single server or on multiple specialized servers.
Figure 7-8
Client/Server Computing on the Internet Management Information Systems, Global Edition
Chapter 7: Telecommunications, the Internet, and Wireless Technology
–Voice over IP (VoIP)
?Digital voice communication using IP, packet switching ?Providers
–Cable providers –Google, Skype
–Unified communications
?Communications systems that integrate voice, data, e-mail, conferencing
–Virtual private network (VPN)
?Secure, encrypted, private network run over Internet
–PPTP –Tunneling
The Global Internet
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A VoIP phone call digitizes and breaks up a voice message into data packets that may travel along different routes before being reassembled at the final destination. A processor nearest the call ’s destination, called a gateway, arranges the packets in the proper order and directs them to the telephone number of the receiver or the IP address of the receiving computer.
Figure 7-9
How Voice over IP Works 7.26
Copyright ? 2014 Pearson Education
This VPN is a private network of computers linked using a secure “tunnel ”connection over the Internet. It protects data transmitted over the public Internet by encoding the data and “wrapping ”them within the Internet Protocol (IP). By adding a wrapper around a network message to hide its content, organizations can create a private connection that travels through the public Internet.
Figure 7-10
A Virtual Private Network Using the Internet
Management Information Systems, Global Edition
Chapter 7: Telecommunications, the Internet, and Wireless Technology
Read the Interactive Session and discuss the following questions
Interactive Session: Management
–Should managers monitor employee e-mail and Internet usage? Why or why not?
–Describe an effective e-mail and Web use policy for a company.
–Should managers inform employees that their Web behavior is being monitored? Or should managers monitor secretly? Why or why not?
Monitoring Employees on Networks—Unethical or Good Business?
Management Information Systems, Global Edition
Chapter 7: Telecommunications, the Internet, and Wireless Technology
?The Web
–Hypertext Markup Language (HTML)–Hypertext Transfer Protocol (HTTP):
?Communications standard used for transferring Web pages
–Uniform resource locators (URLs):
?Addresses of Web pages
–https://www.doczj.com/doc/c018769822.html,/content/features/082602.html
–Web servers
–Software for locating and managing Web pages
The Global Internet
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?Search engines
–Started as simpler programs using keyword indexes –Google improved indexing and created page ranking system
?Mobile search: 20% of all searches in 2012?Search engine marketing
–Major source of Internet advertising revenue
?Search engine optimization (SEO)
–Adjusting Web site and traffic to improve rankings in search engine results
The Global Internet 7.30
Copyright ? 2014 Pearson Education
Google is the most popular search engine on the Web, handling 84 percent of all Web searches.
Figure 7-11
Top U.S. Web Search Engines
Management Information Systems, Global Edition
Chapter 7: Telecommunications, the Internet, and Wireless Technology
?Social search
–Google +1, Facebook Like
?Semantic search
–Anticipating what users are looking for rather than simply returning millions of links
?Intelligent agent shopping bots
–Use intelligent agent software for searching Internet for shopping information
The Global Internet Management Information Systems, Global Edition
Chapter 7: Telecommunications, the Internet, and Wireless Technology
The Google search engine is continuously crawling the Web, indexing the content of each page, calculating its popularity, and storing the pages so that it can respond quickly to user requests to see a page. The entire process takes about one-half second.
Figure 7-12
How Google Works
7.33Copyright ? 2014 Pearson Education
?Web 2.0
–Second-generation services
–Enabling collaboration, sharing information, and creating new services online –Features
?Interactivity
?Real-time user control
?Social participation (sharing)?User-generated content
The Global Internet 7.34
Copyright ? 2014 Pearson Education
–Web 2.0 services and tools
?Blogs: chronological, informal Web sites created by individuals
–RSS (Really Simple Syndication): syndicates Web content so aggregator software can pull content for use in another setting or viewing later –Blogosphere –Microblogging
?Wikis: collaborative Web sites where visitors can add, delete, or modify content on the site
?Social networking sites: enable users to build communities of friends and share information
The Global Internet
Management Information Systems, Global Edition
Chapter 7: Telecommunications, the Internet, and Wireless Technology
?Web 3.0: The “Semantic Web ”
–A collaborative effort led by W3C to add layer of meaning to the existing Web
–Goal is to reduce human effort in searching for and processing information
–Making Web more “intelligent ”and intuitive
–Increased communication and synchronization with computing devices, communities –“Web of things ”
–Increased cloud computing, mobile computing
The Global Internet Management Information Systems, Global Edition
Chapter 7: Telecommunications, the Internet, and Wireless Technology
?Cellular systems
–Competing standards
?CDMA: United States only
?GSM: Rest of world, AT&T, T-Mobile
–Third-generation (3G) networks
?144 Kbps
?Suitable for e-mail access, Web browsing
–Fourth-generation (4G) networks
?Up to 100 Mbps
?Suitable for Internet video
The Wireless Revolution
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?Wireless computer networks and Internet access
–Bluetooth (802.15)
?Links up to 8 devices in 10-m area using low-power, radio-based communication
?Useful for personal networking (PANs)
–Wi-Fi (802.11)
?Set of standards: 802.11
?Used for wireless LAN and wireless Internet access
?Use access points: device with radio receiver/transmitter for connecting wireless devices to a wired LAN
The Wireless Revolution 7.38
Copyright ? 2014 Pearson Education
Bluetooth enables a variety of devices, including cell phones, PDAs, wireless keyboards and mice, PCs, and printers, to interact wirelessly with each other within a small 30-foot (10-meter) area. In addition to the links shown, Bluetooth can be used to network similar devices to send data from one PC to another, for example.Figure 6-15
A Bluetooth Network (PAN)
Management Information Systems, Global Edition
Chapter 7: Telecommunications, the Internet, and Wireless Technology
Mobile laptop computers
equipped with wireless network interface cards link to the wired LAN by communicating with the access point. The access point uses radio waves to transmit network signals from the wired network to the client adapters, which convert them into data that the mobile device can understand. The client adapter then transmits the data from the mobile device back to the access point, which forward the data to the wired network.Figure 7-14
An 802.11 Wireless LAN
Management Information Systems, Global Edition
Chapter 7: Telecommunications, the Internet, and Wireless Technology
?Wireless computer networks and Internet access
–Wi-Fi (cont.)
?Hotspots: one or more access points in public place to provide maximum wireless coverage for a specific area ?Weak security features
–WiMax (802.16)
?Wireless access range of 31 miles ?Require WiMax antennas
The Wireless Revolution
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?Radio frequency identification (RFID)
–RFID tags:
?Tiny tags with embedded microchips contain data about an item and location
?Transmit radio signals over short distances to RFID readers
–RFID readers:
?Send data over network to computer for processing
–Active RFID:
?Tags have batteries ?Data can be rewritten ?Range is hundreds of feet
The Wireless Revolution 7.42
Copyright ? 2014 Pearson Education
?RFID (cont.)
–Passive RFID:
?Range is shorter
?Smaller, less expensive
?Powered by radio frequency energy
–Common uses:
?Automated toll-collection
?Tracking goods in a supply chain
–Requires companies to have special hardware and software
–Reduction in cost of tags making RFID viable for many firms
The Wireless Revolution
Management Information Systems, Global Edition
Chapter 7: Telecommunications, the Internet, and Wireless Technology
RFID uses low-powered radio transmitters to read data stored in a tag at distances ranging from 1 inch to 100 feet. The reader captures the data from the tag and sends them over a network to a host computer for processing.
Figure 7-15
How RFID Works Management Information Systems, Global Edition
Chapter 7: Telecommunications, the Internet, and Wireless Technology
?Wireless sensor networks (WSNs)
–Networks of hundreds or thousands of interconnected wireless devices embedded into physical environment to provide measurements of many points over large spaces –Used to monitor building security, detect hazardous
substances in air, monitor environmental changes, traffic, or military activity
–Devices have built-in processing, storage, and radio frequency sensors and antennas
–Require low-power, long-lasting batteries and ability to endure in the field without maintenance
The Wireless Revolution
A Wireless Sensor Network
The small circles represent lower-level nodes and the larger circles represent high-end
nodes. Lower-level nodes forward data to each other or to higher-level nodes, which
transmit data more rapidly and speed up network performance.
Figure 7-16
7.45Copyright ? 2014 Pearson Education
7.46Copyright ? 2014 Pearson Education
离散数学知识点总结 一、各章复习要求与重点 第一章 集 合 [复习知识点] 1、集合、元素、集合的表示方法、子集、空集、全集、集合的包含、相等、幂集 2、集合的交、并、差、补等运算及其运算律（交换律、结合律、分配律、吸收律、 De Morgan 律等），文氏（V enn ）图 3、序偶与迪卡尔积 本章重点内容：集合的概念、集合的运算性质、集合恒等式的证明 [复习要求] 1、理解集合、元素、子集、空集、全集、集合的包含、相等、幂集等基本概念。 2、掌握集合的表示法和集合的交、并、差、补等基本运算。 3、掌握集合运算基本规律，证明集合等式的方法。 4、了解序偶与迪卡尔积的概念，掌握迪卡尔积的运算。 [本章重点习题] P5~6，4、6； P14~15，3、6、7； P20，5、7。 [疑难解析] 1、集合的概念 因为集合的概念学生在中学阶段已经学过，这里只多了一个幂集概念，重点对幂集加以掌握，一是掌握幂集的构成，一是掌握幂集元数为2n 。 2、集合恒等式的证明 通过对集合恒等式证明的练习，既可以加深对集合性质的理解与掌握；又可以为第三章命题逻辑中公式的基本等价式的应用打下良好的基础。实际上，本章做题是一种基本功训练，尤其要求学生重视吸收律和重要等价式在B A B A ~?=-证明中的特殊作用。 [例题分析] 例1 设A ，B 是两个集合，A={1，2，3}，B={1，2}，则=-)()(B A ρρ 。 解 }}3,2,1{},3,2{},3,1{},2,1{},3{},2{},1{,{)(φρ=A }}2,1{},2{},1{,{)(φρ=B 于是}}3,2,1{},3,2{},3,1{},3{{)()(=-B A ρρ
1.【实验目的】 对称： 通过算法设计并编程实现对给定集合上的关系是否为对称关系的判断，加深学生对关系性质的理解，掌握用矩阵来判断关系性质的方法 自反： 通过算法设计并编程实现对给定集合上的关系是否为自反关系的判断，加深学生对关系性质的理解，掌握用矩阵来判断关系性质的方法。 2.【实验内容】 已知关系R 由关系矩阵M 给出，要求判断由M 表示的这个关系是否为对称关 系。假定R 的关系矩阵为：?????? ? ??=1234210330124321M 3.【实验要求】 C 语言编程实现 4.【算法描述】 对称： 从给定的关系矩阵来判断关系R 是否为对称是很容易的。若M （R 的关系矩阵）为对称矩阵，则R 是对称关系；若M 为反对称矩阵，则R 是反对称关系。因为R 为对称的是等价关系的必要条件，所以，本算法可以作为判等价关系算法的子程序给出。 算法实现： （1） 输入关系矩阵M （M 为n 阶方阵）； （2） 判断对称性，对于i=2，3，….，n ；j=1，2,……，i-1，若存在m ij =m ji ， 则R 是对称的； （3） 判断反对称性； （4） 判断既是对称的又是反对称的； （5） 判断既不是对称的又不是反对称的； （6） 输出判断结果。
自反： 从给定的关系矩阵来断判关系R是否为自反是很容易的。若M（R的关系矩阵）的主对角线元素均为1，则R是自反关系；若M（R的关系矩阵）的主对角线元素均为0，则R是反自反关系；若M（R的关系矩阵）的主对角线元素既有1又有0，则R既不是自反关系也不是反自反关系。本算法可以作为判等价关系算法的子程序给出。 算法实现 （1）输入关系矩阵M（M为n阶方阵）。 （2）判断自反性，对于i=1，2，….，n；若存在m =0，则R不是自反 ii =1，则R是自反的；否则R既不是自反关系也不是的；若存在m ii 反自反关系。 （3）输出判断结果。 源代码 #include
湖南师范大学硕士研究生入学考试自命题考试大纲 考试科目代码：考试科目名称：离散数学 一、试卷结构 1) 试卷成绩及考试时间 本试卷满分为100分，考试时间为180分钟。 2)答题方式：闭卷、笔试 3)试卷内容结构 集合论40% 数理逻辑40% 图论20% 4)题型结构 a: 填空题，5小题，每小题5分，共25分 b: 计算题，3小题，每小题10分，共30分 c: 证明题，3小题，每小题15分，共45分 二、考试内容与考试要求 1、集合论 考试内容 集合及其表示集合的运算与性质二元关系的概念二元关系的五种性质关系矩阵与关系图关系的各种运算与性质关系闭包与性质相容关系等价关系序关系部分函数、满射、内射、双射的概念可逆、左可逆、右可逆函数特征函数集合的基数与性质 考试要求 （1）理解集合的表示、二元关系的概念、部分函数、满射、内射、双射的概念可逆、左可逆、右可逆函数的概念； （2）掌握集合的运算与性质、关系的五种性质、关系的运算与性质、关系闭包与性质、相容关系、等价关系、序关系. （3）了解特征函数集合的基数与性质．
2、数理逻辑 考试内容 命题与命题的真值五个基本联结词命题符号化合式公式真值表合式公式的类型等价式、蕴含式的证明范式和判定问题求主范式的方法变元、谓词和量词量词的辖域、前束范式合式公式的解释、求合式公式在给定解释下真值的方法 考试要求 （1）理解命题与命题的真值、联结词、合式公式与真值表、变元、谓词和量词等概念． （2）掌握合式公式的类型、等价式、蕴含式的证明、求主范式的方法、合式公式的解释、以及求在给定解释下真值的方法． （3）了解量词的辖域、前束范式． 3、图论 考试内容 图的基本概念路与回路和连通性图的矩阵表示欧拉图和哈密顿图平面图对偶图与着色树与生成树根树及其应用 考试要求 （1）理解图、路、回路和连通性等基本概念． （2）掌握一些特殊图类的性质，树的特征与应用． 三、参考书目 [1] 左孝凌等，《离散数学》，上海科技文献出版社，1982年 [2] 王兵山、张强、毛晓光，《离散数学》，国防科技大学出版社，1998年 [3] 耿素云、屈宛玲，《离散数学》，高等教育出版社，2003年