1.Subnotebooks users give up a full size display screen and keyboard in exchange for less weight.
2.They fall in between microcomputers and mainframes in their processing speeds and data-storing capacities。
3.The speed of microcomputer output devices tends to be rated in terms of the number of characters per second (cps) that can be printed----usually in tens and hundreds of cps.
4.The purpose of storage hardware is to provide a means of storing computer instructions and data in a form that is relatively permanent,that is,the data is not lost when the power is turned off and easy to retrieve when needed for processing.
5.An electric field causes the molecules to line up in a way that alters optical properties.
6.The characters are treated with a magnetically charged inklike toner and then are transferred from drum to paper.
7.Rather,it is an advanced alternative designed for very powerful microcomputers and networks。
8.With multitasking,the speed at which the document is printed is affected by the demands of database management program.
9.A common method of determining what errors have been introduced into an image is by modeling the scene at the time of data acquisition using ancillary data colleted.
10.Geometric rectification is a process by which points in an image are registered to corresponding points on a map or another image that has already been rectified.
11.Neural networks attempt to "teach" the computer what decisions to make based up on a training data set.
12.This combination could seriously limit one of the Web's most appreciated aspects-its ability to present images easily.
13.That would cut down the number of bytes by three-fourths,at least in the one corner.
14.The longer the run of pixels,the more compression.
15.It involves reducing the amount of memory needed to store a digital image.
16.The example below demonstrates how one could go about extracting measurements from an image.
17.If you really want to be sirict,computer pictures are files,the same way WORD documents or solitaire games are files.
18.That is,all of the objects shown on the computer monitor are representations of points and their relationship to each other on the work area,each of which is stored in the computer as simple values and mathematical equations depicting:the relationship between each point and the next point referenced to it,and the position(vector) of each point referenced to a starting corner of the work area.
19.At such an enlargement,the picture would be of little use for reproduction unless viewed from quite a long distance.
20.Although the concept of a secure network is appealing to most users,networks cannot be calssified simply as secure or not secure because the term is not absolute--each group defines the level of access that is permitted or denied.
21.The more people use Internet,the more concerns about Internet security.
22.Almost all encryption schemes used in the Internet uses asymmetric key encryption for exchanging the symmetric encryption key,and symmetric encryption for better performance.
23.If the application is really the one "who claims to be",CA will issue a digital certificate,with the applicant's name,E-mail address and the applicant's public key,which is also signed digitally with the CA's private key.
24.Many people pay great amounts of lip service to security,but do not want to be bothered with it when it gets in their way.
25.Just as human viruses invade a living cell and then turn it into a factory for manufacturing viruses,computer viruses are small program that replicate by attaching a copy of themselves to another program.
26.Skillfully written virus can infect and multiply for weeks or mouths without being detected.
27.The timing of the attack can be linked to a number of situations,including : a certain time or date;the presence of a particular userID,the use or presence of a particular file,the security privilege level of the user,and the number of times of a file is used.
28.Very difficult to write,these viruses have the ability,once booted up,to take total control of your system.
29.Source code viruses are intrusive programs that are inserted into a source program such as those written in Pascal prior to the program being compiled。
30.When it comes to information security, most companies fall somewhere between two extreme boundaries:complete access and complete security.
31.Unfortunately,having a computer with complete access is also not practical because it would expose every bit of information publicly,from customer records to financial documents.
32.This is a property of an information system whereby its availability,reliability,completeness and promptness are assured.
33.These options typically include a table of contents, a search feature to locate reference information about specific commands,and central options to move around.
34.These industries have profited from the productivity gains of using hand-held terminals and notebook computers to transmit real-time information to centralized hosts for processing.
35.Wireless LANs frequently augment rather than replace wired LAN networks--often providing the final few meters of connectivity between a backbone network and the mobile user.
36.Inexpensive,multiple-conductor cable comprised of one or more pairs of 18 to 24 gauge copper strands.
37.A transmission medium composed of a central glass optical fiber cable surrounded by cladding and an outer protective sheath.
38.This type of system is common in decentralized organizations where divisional offices have their own computer systems.
39.Networks can be controlled by all nodes working together equally or by specialized nodes coordinating and supplying all resources.
40.Serial transmission is the way most data is sent over telephones lines.
41.It separates each network's function into seven "layers" of protocols,or communication rules.
42.This assumes that the microcomputers and other equipment on each network have implemented the same functions and interfaces.
43.Satellite communications refers to the utilization of geostationary orbiting satellites to relay the transmission received from one each earth station to one or more earth stations.
44.The home page presents information about the site along with references and hyperlinks, or connections to other documents that contain related information such as text files,graphic images,audio,and video clips.
45.At a business level,electronic communication has become standard and many times preferred way to stay in touch with suppliers,employess,and customers.
46.Search engines are specialized programs that assist you in locating information on the Web and the Internet.
47.Search engines order the hits according to those sites that most likely contain the information requested and present the list to you in that order,usually in groups often.
48.If you have access to a personal computer(PC) and can cannect to the Internet with a browser, you can do business online.
49.No business can afford to ignore the potential of a connected economy.
50.Unlike traditional sales via classified ads and auctions,buyers and sellers typically never meet face-to-face.
51.As for other major froms of system software,such as compliers and operating systems,a well-understood set of principles for databases management systems has developed ove the years,and these concepts are useful both for understanding how to use these systems effectively and for designing and implementing DBMS's.
52.While we regard the above two properties of a DBMS as fundamental, there are a number of other capabilities that are almost universally found in commercial DBMS's.
53.But if you are in the bank depositing your salary check at the exact instant your spouse is extracting money from an automatic teller,the result of the two transactions occurring simultaneously and without coordination is unpredictable.
54.They are called high-level languages because they remove many of the complexities involved in the raw machine language that computers understand.
55.The key point is that object oriented languages are more modern,and using object oriented languages is the way things are done now in the programming world.
56.Each object can contain different data,but all objects belonging to a class have the same functions(called methods).
57.Often in the program you will refer to an email object as if it was the parent(super-class) because it will not matter whether the email contains a picture,or sound,or just text.
58.There are at least three approaches to OO languages:Methods in Classes,Multi-Methods Separate from Classes,Prototypes.
59.Once you have narrowed down the line where your bug occurs, the next step is to find out the value of your variables at that time.
60.The syntax errors aren't a serious issue during tht program design phase since in practice,after designing and testing the design,the program will be implemented in a computer program language and it is at this point that syntax errors become a problem.
61.Computers are electronic devices that can follow instructions to accept input,process that input,and produce information.
62.The term instruction is used here to describe a basic task the software asks the computer to perform while also identifying the data to be affected.
66.One of the most important facts to know about memory is that part of its content is held only temporarily.
67.Hard disks are assembled under sterile conditions and sealed from impurities within their permanent containers.
68.A problem with human language is that it can seem to be imprecise.
69.Pseudocode is also human language but tends toward more precision by using a limited vocabulary.
70.Multi-dimensional object fromats store graphics data as a collection of objects(data and the code that manipulates it)that may be rendered(displayed)in a variety of perspectives.
71.Virtual Reality Modeling Language(VRML) is a 3D,object-oriented language used for describing "virutal worlds" networked via the Internet and hyperlinked within the World Wide Web.
72.Image defects which could be caused by the digitization process or by faults in the imaging set-up(for example,bad lighting)can be corrected using Image Enhancement techniques.
73.The example below represent only a few of the many techniques available for operating on images.Details about the inner workings of the operations have not been given.
74.Although it has several remarkable features, such as transparency and the ability to present animated images, it is not well suited for the presentation of continuous tone images,such as photographs, due to its limit of 256 colors.
75.“Compression” is a compution term that represents a variety of mathematical formats used to compress an image's byte size.
76.Remote sensing is the process of collecting data about objects or landscape features without coming into direct physical contact with them.
77.Information Extraction—Unlike analog image processing,digital image processing presently relies almost wholly on the primary elements of tone and color of image poxels.
78.The select statement is used to query the database and retrieve selected data that match the criteria that you specify.
79.The table name that follows the keyword from specifies the table that will be queried to retrieve the desired results.
80.The where clause(optional) specifies which data values or rows will be returned or displayed,based on the criteria described after the keyword where.
81.Although most database systems use SQL,most of them also have their own additional proprietary extensions that are usually only used on their system.
82.To create a new table,enter the keywords create table followed by the table name,followed by an open parenthesis, followed by the first column name, followed by the data type for that column,followed by any optional constraints, and followed by a closing parenthesis.
83.Management of data involves both defining structures for storage of information and providing mechanisms for the manipulation of information.
84.Dialog boxes frequently appear after selecting a command from a pull-down menu.These boxes are used to specify additional command options.
85.Scroll bars are usually located on the right and/or the buttom of the screen.They enable you to display additional information not currently visible on the screen.
86.Browsers are programs that provide access to Web resources.
87.These documents may be located on a nearby computer system or on one halfway around the world.
88.Mailing lists allow members of a mailing list to communicate by sending messages to a list address.
89.Before you submit a contribution to a discussion group,it is recommended that you observe or read the communications from others.This is called lurking.By lurking,you can learn about the culture of a discussion group.
90.Metasearch engines are programs that automatically submit your search request to several search engines simultaneously.
91.Specialized search engines focus on subject-specific Web sites.Specialized sites can potentially save you time by narrowing your search.
92.The wired world of business,developed technology,human talent, and a new way of doing business make up today's growing worldwide economy.
93.The backbone of this electronic commerce is the Internet.
94.Electronic commerce is an emerging concept that describes the process of buying and selling or exchanging of products,services,and information via computer networks including the Internet.
95.Businesses receive raw materials as input,add value to them through various processes,and sell the finished product as output to customers.
96.Competitive advantage is achieved when an organization links the activities in its value chain more cheaply and more effectively than its competitors.
97.There is no time sequence or special sequence of activities before a business is considered successful or effective.
98.E-commerce can play a key role in reducing costs,improving product quality and integrity,promoting a loyal customer base,and creating a quick and effecient way of selling products and services.
99.The integration of these activities results in an organization fine-tuned for profitability and growth.
100.Bringing in qualified people contributes to stability,continuity,and integrity of operations throughout the firm.