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employees are not trained on the new tools and how it can streamline their work, than they are less likely to best utilize the new software. Implementing enterprise software without staff training virtually guarantees that large chunks of functionality will be lost due to employee ignorance. Staff will become frustrated, avoid using the software when possible and negatively impact the operations bottom line. Training should therefore be a priority

Сduring the implementation period.

Staff members must be trained not only on how to use the software, but the organizational benefits that this new system provides. A process must be put in place that can provide this information, while offering a platform from иwhich employers can address any lingering concerns that employees may have. Let’s face it, change of any kind is a scary thing for most people and there will be those who object. Smart companies, with the help of knowledgeable ERP vendors, can guide employees through this change and help staffбАto realize the enormous benefits that the new system can provide.

Finally, ERP solution providers should offer adequate technical support to guide an enterprise through the first weeks after implementation and address any issues that arise over time. Comprehensive help services should include a telephone hotline, as well as Web and on-site support. These services help to ensure that your company will receive maximum return on its technology investment.

NEW APPROACH TO GENERATING

TRULY RANDOM NUMBERSДMAY IMPROVE INTERNET

SECURITY, WEATHER FORECASTS

A new approach to generating truly random numbers could lead to improved Internet security and better weather forecasts, according to researchers writing in the International Journal of CriticalИComputer-Based Systems.

Random numbers are a critical part of computer and Internet security. They allow websites and browsers to encrypt the data sent between them using a session key. Weather forecasters, climate scientists, economists, and epidemiologists also use random numbers to generate simulated data for their predictive models. Such simulations can test theories of hurricane formation, climate change, and the spread of disease epidemics, for instance.

According to Bernhard Fechner of the University of Hagen, and Andre Osterloh of BTC AG, in Germany, the "quality" of a random number is a measure of how truly random the number is. This quality affects significantly any security or simulation in which it is used. If a so-called random number is not truly random, then someone could predict a security key and crack the Internet encryption on bank accounts, e-commerce sites or secure

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government websites, for instance. Similarly, if the random numbers used in scientific models of the weather, climate, or the spread of disease and economic boom and bust are predictable, then systematic errors will creep into the models and make the predictions unreliable.

Fechner and Osterloh explain that a good random number in computer binary would usually comprise discrete and uniformly distributed ones and zeroes.

СIn such a sequence there is no way to predict what digit will appear next, the

number is thus random. In reality, it is unfeasible to generate a sequence that is totally unpredictable by computational means. Therefore, physical means are used to generate true random numbers.

иcontents of the memory are purely random.

The German team has now developed a true random number generator that uses an extra layer of randomness by making a computer memory element, a flip-flop, twitch randomly between its two states 1 or 0. Immediately prior to the switch, the flip-flop is in a "metastable state" where its behaviour cannot be predicted. At the end of the metastable state, the

predict withбАany degree of certainty the next number in a sequence compared to current random number generators.ДThis could be used to improve everything from climate change models to stock market predictions.

The researchers' experiments with an array of flip-flop units show that

for small arrays the extra layer makes the random number almost twenty

times more "random" than conventional methods. The degree of randomness

possible depends on the size of the array and so a bigger array could be even

more effective. Essentially, this means that the bigger the array the better the

quality of random numbers. As such, it is many times more difficult to

The team adds that the efforts of a cracker attempting to influence the array will be wholly obvious to a simple statistical analysis as – depending on

the type of attack – either the whole array or single elements will be disturbed, whereas these are again selected randomly.ИSo this true random

number generator can protect systems against third-party snooping, potentially making private and sensitive transactions on the Internet more secure.

COMPUTERS

Most people tend to think about computers in terms of the systems that they use at home or at work. Most of the time these are "stand-alone" models, such as desktops, laptops, or notebooks, and sometimes they are wireless devices, such as palm pilots, personal organizers, and third-generation cellular phones that allow access to e-mail and the Internet. Although public health has not yet taken full advantage of these technologies, it is important

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to understand the basics of these technologies in order to visualize their potential uses in the near and long-term future

Initially, the computer was conceived as a device to manipulate numbers and solve arithmetical problems. During its development, it was recognized that a machine capable of manipulating numbers could also be used to manipulate any "symbol" represented in numeric form. An electronic

Сdata processing system (EDPS) involves at least three basic elements: the input entering the system, or source data; the orderly processing that takes place within the system; and the output, or end result. The EDPS has four functional units: the input devices; the central processing unit (CPU); the иstorage, or memory; and the output devices.

The central processing unit (CPU) is the control center of the EDPS, and it has two parts: the "arithmetic/logic unit" (ALU) and the "control unit." The ALU performs operations such as addition, subtraction, multiplication, and division;бАas well as moving, shifting, and comparing data. The control section of the CPU directs and coordinates all the operations of the computer according to the conditions set forth by the stored program. It selects instructions from the stored program and interprets them. It then generates signals and commands that cause other system units to perform certain operations at appropriate times. It controls the input/output units, the arithmetic-logic operations of the CPU, and the transfer of data to and from storage. It acts as a central nervous system, but performs no actual processing operations on data.

Storage Devices. The mainДstorage of a computer—the memory, or internal storage unit – is basically an electronic filing cabinet where each location is capable of holding data and instructions. The storage unit contains four elements: (1) all data being held for processing, (2) the data being processed, (3) the final result of processing until it is released as output, and

(4) all the program instructions while processingИis being carried out. Each location in main storage is identified by a particular address. Using this address, the control section can readily locate data and instructions as needed. The size or capacity of main storage determines the amount of data and instructions that can be held within the system at any one time. In summary, the internal memory is a temporary storage and is called "random access memory" (RAM). There is also a second type of memory, called "read-only memory" (ROM). This memory is fixed; meaning it can be read but cannot be written to, changed, or deleted. There are also secondary memory devices or auxiliary storage, sometimes called "sequential access memory," such as diskettes, hard drives, and magnetic tape. Depending on how often the data will be used these auxiliary devices will be chosen. For example, mass storage devices or certain types of tapes may be used for archival purposes of

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medical records or bank accounts, where certain legal aspects of the data may be required.

Input/Output (I/O) Devices. These are devices that are linked to the computer and can introduce data into the system, and devices that can accept

data after it has been processed. Some examples are: disk storage drives, printers, magnetic tape units, display stations, data transmission units, and the Сold punched card or paper tape. Input devices perform the function of

converting the data from a form that is intelligible to the user to a form that is

intelligible to the computer. Output, on the other hand, is data that has been

processed, (e.g., shown on a display device). In some cases, a printer can

иcontrol-sequenced instructions stored within the memory of the device. Some common forms of storing data today include: floppy disks (used mainly for

readily display the data in an understandable form. In other instances, such as

with a magnetic tape drive, the data is carried as input for further processing

by another device. In this case, the computer retains the data until further

processing takes place. In summary, a digital computer identifies an

ComputerбАSystem. The computer elements described thus far are known as "hardware." A computerДsystem has three parts: the hardware, the software, and the people who make it work. The computer software can

electronic device capable of manipulating bits of information under the

temporary storage); magnetic disks (fixed or removable); and optical disks that can store very large amounts of data. CD-ROM (compact disk— read only memory) devices store the information by means of a finely focused laser beam that detects reflections from the disc. This technology is sometimes referred by the term "write once, read many times" (WORM).

broadly be divided in two categories: systems software and application software or programs. These systems software can be further divided into:

operating systems and programming languages. A computer program is a set of commands (in the form of numeric codes)Иthat is put into the computer's memory to direct its operation. Testing, or debugging, is done to check if a program works properly. The ongoing process of correcting errors and modifying working programs is called software maintenance. The science of software engineering has provided formal methods for writing and testing programs.

DATA PROCESSING, DATA REPRESENTATION

When people communicate by writing in any language, the symbols used (the letters of the alphabet, numerals, and punctuation marks) convey information. The symbols themselves are not information, but representations of information. Data in an EDPS must be expressed symbolically so that the machines can interpret the information presented by humans. In general, the

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symbols that are read and interpreted by a machine differ from those used by people. The designer of a computer system determines the nature and meaning of a particular set of symbols that can be read and interpreted by the system. The actual data that is used by these systems is (or was in the past) presented as holes on punched cards or paper tape, as spots on magnetic tape, as bits (binary digit) or bytes of information in a disk, diskette, CD-ROM, or

Сoptical disk; as magnetic-ink characters; as pixels in display-screen images; as points in plotted graphs; or as communication-network signals.

In many instances, communication occurs between machines. This communication can be a direct exchange of data in electronic form over иcables, wires, radio waves, infrared, satellites or even wireless devices such as cellular phones, pagers, and hand-held personal organizers and/or notebooks. It can also be an exchange where the recorded or stored output of one device or system becomes the input of another machine or system.

In theбАcomputer, data is recorded electronically. The presence or absence of a signal in specific circuitry represents data in the computer the same way that the absence or presence of a punched hole represented data in a punched card. If we think of an ordinary lightbulb being either on or off, we could define its operation as a binary mode. That means that at any given time the lightbulb can be in only one of two possible conditions. This is known as a "binary state." In a computer, transistors are conducting or nonconducting; magnetic materials are magnetized in one direction or in the opposite direction; a switch or relay is either on or off, a specific voltage is either present or absent. These areДall binary states. Representing data within the computer is accomplished by assigning a specific value to each binary indication or group of binary indications. Binary signals can be used to represent both instructions and data; consequently the basic language of the computer is based primarily on the "binary number system."

A binary method of notation is usuallyИused to illustrate binary indications. This method uses only two symbols: 0 and 1, where 0 and 1 represent the absence and presence of an assigned value, respectively. These symbols, or binary digits, are called "bits." A group of eight bits is known as a "byte," and a group of 32 bits (4 bytes) is known as a "word." The bit positions within a byte or a word have place values related to the binary number system. In the binary number system the values of these symbols are determined by their positions in a multidigit numeral. The position values are based on the right to left progression of powers having a base of 2 (20, 21, 22, 23), commonly employed within digital computers. For example, if there are four light bulbs next to each other numbered 4, 3, 2, and 1 and 1 and 3 are "on" and 2 and 4 are "off," the binary notation is 0101.

The system of expressing decimal digits as an equivalent binary value is known as Binary Coded Decimal (BCD). In this code, all characters (64

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characters can be coded), including alphabetic, numeric, and special signs, are represented using six positions of binary notation (plus a parity bit position). The Extended Binary Coded Decimal Interchange Code (EBCDIC) uses eight binary positions for each character format plus a position for parity checking (256 characters can be coded). The American Standard Code for Information Interchange (ASCII) is a seven-bit code that offers 128 possible

Сcharacters. ASCII was developed by users of communications and data processing equipment as an attempt to standardize machine-to-machine and system-to-system communication.

Computer Number Systems and Conversions. Representing a

иdecimal number in binary numbers may require very long strings of ones and zeros. The hexadecimal system is used as a shorthand method to represent them. The base of this system is 16, and the symbols used are: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E and F. In other words, F is 15 in decimal notation and 1 1 1 1 inбАbinary.

Programming Languages Techniques. Assembler languages are closer to machine instructions than to human language, and having to express logical procedures, arithmetical calculations, and textual manipulations in these languages affects a programmer's productivity because they are so cumbersome. There are many higher-level programming languages, such as ALGOL, BASIC, COBOL, FORTRAN, and Pascal, that are much closer to human means of expression.

A programmer writes a source program in a human-readable programming language. A compilerДtranslates these English-like statements into instructions that the computer can execute—such instructions are called an "object program." Through added library routines the computer does further processing of the object program, executes it, and an "output" is produced. There are some "optimizing compilers" that automatically correct obvious inefficiencies in source programming.ИSometimes, with the use of "interpreters," debugging can be done to a program as it executes the user program piece by piece. MUMPS, LISP, and APL are interpreters used for this purpose in the health care environment, artificial intelligence, and mathematics fields, respectively. Because of the time and costs associated with development, it is generally not cost effective in today's environment to develop an application package, but rather buy it (if available) from a vendor. The costs are thus spread among thousands of users. Typical applications packages used for public health purposes are SAS and SPSS (for biostatistics) and ArcView/GIS (for Geographical Information Systems). In addition there are some data manipulation languages (e.g., Oracle and dBASE) that were written with this purpose. A database manipulation language (DML) is a special sublanguage used for handling data storage and

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retrieval in a database system. Using a data definition language (DDL), programmers can organize and structure data on secondary storage devices.

Data Acquisition. Capturing and entering data into a computer is expensive. Direct acquisition of data avoids the need for people to read

values and measure, encode, and/or enter the data. Automated data acquisition can help eliminate errors and speed up the procedure. Sensors Сconnected to a patient convert biological signals into electrical signals that

are transmitted into a computer. Many times these signals (e.g., ECG, blood pressure, heart rate) are analog signals, and in order to be stored into a digital signal a conversion needs to occur. This process is called analog to digital иconversion (ADC).

DATABASES AND DATABASE

MANAGEMENT SYSTEMS

A databaseбА(DB) system is a computer-based record keeping system used to record and maintain certain types of information that have a significant value to some organization. A DB is a repository of stored data, which in general is both integrated and shared. Between the physical database and the users of the system is a layer of software, usually called the database management system (DBMS). All requests from the users to access the DB are handled by the DBMS.

When trying to organize the data and information within an organization, the DB helps the userДin entering, storing, and retrieving it, and when trying to integrate all or part of the information of the enterprise the DB becomes a key player. Normally, within the DB, information is organized into data elements, fields, records, and files. In a system such as a hospital information system (HIS), a patient name is a data element or a field; a record could be related to that patient's visit onИa particular date (e.g., date, diagnoses, treatments, charges, medications, tests) at a particular time; and a file would contain all the information from all the visits for that patient. An HIS DB will include not only patient files, but it could also have accounting information related to charges, inventory, payroll, and personnel records. With DB systems, different people can have access to different parts of the system, so, for example, not all personnel employees will have access to laboratory results.

The DBMS organization and definition of the contents of the individual data elements, fields, records, and files are provided via a machine-readable definition called "schema." This creates an independence of physical location from logical location of the content of a DB. The DBMS not only "manages the DB" but also allows for entering, editing, and retrieving results. The

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DBMS helps with the integration of data coming from multiple sources. The user can also access and retrieve specific types of information via queries.

A DB provides an organization with centralized control of its operational data. Some of the advantages of having centralized (versus distributed) control of the data are:

	Redundancies can be reduced.
	Inconsistencies can be avoided.
	Data can be shared.
	Standards can be enforced.
	Privacy, confidentiality, authenticity, and security restrictions can be
	applied.
СIntegrity can be maintained.
	Conflicting requirements (among users) can be balanced (for the
	бА
	enterprise).
	Data is easier to support (the single repository, the application, and the
иendusers).

Due to technological advancements, databases today are much more complex than a few decades ago. They contain "multimedia" information, such as text, graphics, scanned images from documents, clinical images from all modalities (X-rays, ultra-sound, MRI, CT scan), still and dynamic studies, and sound. When doing population studies, the creation of data "warehouses" is necessary, and data "mining" techniques are used to extrapolate results. In public health, the data needed for a study can reside in a small computer, in a local area network (LAN), or in a wide area network (WAN). In order to use information that is geographically distributed (and/or with distributed users) it is important to learn techniques for data integration and data communications. Because of the continuing fusion of computers and

	communications, this is the fastest changing area within information
	technology.	Д
		И

INTERNET AND

THE WORLD WIDE WEB

There is little historical precedent for the swift and dramatic growth of the Internet, which was originally a limited scientific communication network developed by the U.S. government to facilitate cooperation among federal researchers and the university research community. With its rapid adoption by the private sector, the Internet has remained an important research tool, and it is also becoming a vital ingredient in maintaining and increasing the scientific and commercial leadership of the United States. In the twenty-first century, the Internet will provide a powerful and versatile environment for

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business, education, culture, entertainment, health care and public health. Sight, sound, and even touch will be integrated through powerful computers, displays, and networks. People will use this environment to work, study, bank, shop, entertain, visit with each other, and communicate with their health care providers. Whether at the office, at home, or traveling, the environment and its interface will be largely the same, and security,

Сreliability, and privacy will be built in. Benefits of this dramatically different environment will include a more agile economy, improved health care (particularly in rural areas), less stress on ecosystems, easy access to lifelong and distance learning, a greater choice of places to live and work, and more иopportunities to participate in the community, the nation, and the world.

Internet and WWW Acronyms. People that communicate with each other electronically may not have the same "platform." "Cross-platform" means that people do not have to use the same kind of operating system to access filesбАon a remote system. In order to access the Web there are two basic mechanisms: (1) using the telephone system to link to another computer or network that is connected to the Internet, and (2) connecting to a network; and from there into the Internet. An Internet service provider (ISP) may be required to access the Internet. An important factor regarding Internet access is bandwidth, which determines how much data a connection can accommodate and the speed at which data can be accessed.

Information on the Web is generally written in Hypertext Markup Language (HTML), which is a text-based markup language that describes the structure of a Web document's content andДsome of its properties. It can also be viewed as a way of representing text and linking it to other resources, such as multimedia files, graphic files, still or dynamic images files, and sound files. HTML contains the information or text to be displayed and the control needed for its display or playback.

File Transfer Protocol (FTP), a cross-platformИprotocol for transferring files to and from computers anywhere on the Internet.

Gopher, a tool for browsing files on the Internet.

Usenet, a worldwide messaging system through which anyone can read and post articles to a group of individuals who share the same interests.

Wide Area Information Server (WAIS), one of a handful of Internet search tools that can be spread across the network to scour multiple

archives and handle multiple data formats.

Hyperlink (also called link), a pointer — from text, from a picture or a

graphic, or from an image map — to a page or file on the World Wide

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Web; hyperlinks are the primary way to navigate between Web pages and among Web sites.

Today, a Web browser is the main piece of software required by the end user to find information through Internet. Some of the most popular browsers

are: Lynx, Mosaic, Netscape Navigator/Communicator, and Internet Explorer. Lynx is a text-only Web browser; it cannot display graphical or Сmultimedia elements. Mosaic, a graphical Web browser, was the first "full-

featured" graphical browser for the Web. It was developed by a team of programmers at the National Center for Supercomputing Applications (NCSA). One of these programmers, Marc Andreesen, later formed Netscape. Netscape Navigator/Communicator is one of the most popular Web browsers. Internet Explorer is Microsoft's Web browser.

Web Resources. A Uniform Resource Locator (URL) is a Web resource that describes the protocols needed to access a particular resource or site on

	бА
the Web, and then point to the resource's Internet location. URLs are, in
short, used to locate information on the Web.
иNormally the URL is composed of six parts:
1.	The protocol or data source (i.e., ftp://, gopher://, news://, telnet://,
WAIS://, http://)
2.	The domain name (for the Web server where the desired information
resides)		Д
3.	The port address
4.
	The directory path (location of the Web page in the Web server's file
system)
5.	The object name
6.	The spot (precise location within the file)
	Protocols are the rules and formats that govern the methods by which
		И

computers communicate over a network. Protocols link clients and servers together and handle requests and responses, including making a connection, making a request, and the closing of the connection. Transmission Control Protocol/Internet Protocol (TCP/IP) is the full set of standard protocols used on the Internet. Hypertext Transfer Protocol (HTTP) is an Internet protocol specifically for the World Wide Web. It provides a way for Web clients and servers to communicate primarily through the exchange of messages.

Multipurpose Internet Mail Extension (MIME) is a technique designed to insert attachments within individual e-mail files. MIME allows a Web server to deliver multiple forms of data to the user in a single transfer. Also, when creating a Web page, it could include text files as well as nontext files, such as sound, graphics, still images, and videos.

Intersection and Information Technology and Public Health. The applications of IT in public health are numerous and varied. One particularly

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