Information Page

- 4 Chapter 1 Data, Information, Knowledge • The Symbol Data System • Information Who? What? When? Where? • Knowledge How?Why? Figure 1.1. Data, Information, Knowledge. By A. Debons, drawn by S. Masters. Data, Information, and Knowledge Information is also that which is in our heads (cognitive/affective), part of our state of consciousness. A primary source of information is our senses: sight, sound, smell, touch, taste, balance, etc. If you were listening to a Walkman or a radio while reading this text, you would be receiving audio messages as well as visual messages. It would be two channels of information coming at you at once. Here's another example: If you were reading this book in your home and noticed the smell of food cooking in the kitchen, you would be receiving two channels of information-one from the reading and another from the smell of the food cooking in the kitchen. We are surrounded by a constant barrage of messages containing information, both from our mind and from the physical world around us (see figure 1.1). In the common view, data are the collection of numbers, measurements, and simple signals that surrourid us every day. Consider a child's science experiment involving a balloon, clock, thermometer, and ruler. The time is 9:30 a.m., the temperature is 70°, and the balloon is 6 inches in diameter (see figure 1.2). The layman's view is that when we reflect on data and organize them into a structure, the result can become information, which is built out of patterns of data. For instance, if we took a series of measurements using the clock, thermometer, and balloon, we might end up with the above (see table 1.1). So now that we have organized this data into a structure, the common view would say that we now have information. But let's look at our information. Introduction to Information 5 G) Figure 1.2. Data Collection. By A. Debons, drawn by S. Masters. Looking at the chart, can you spot any patterns? Can you find an explanation for the changing size of the balloon? You might discover a pattern: the size of the balloon varies with the temperature; when the temperature goes up, the balloon grows; when the temperature falls, the balloon shrinks. So we think we have recognized a pattern: balloon size varies with temperature. The common view would say that this pattern, which we have found by looking at our information, would qualify as knowledge. So to restate: the common view holds that data are composed of the simple measurements around us, information is built out of an organization of data, and knowledge is built out of patterns in the information (see figure 1.3). Introduction to Information Concepts How can we describe information? Since information is all around us, the question is like asking a fish to describe water or asking a bird to describe air. We can start understanding information if we consider information as both a process and a product. Information exists through the processes engaged by our brains in responding to the conditions of matter and energy around us. Information can also be the product in physical form that we generate as part Table 1.1. Organized Data Becomes Information. Time Temperature Size 9:30 70 6" 9:45 74 6.5" 10:00 78 7" 10:15 74 6.5" ', Data - Information -Knowledge Information is awareness Data ~1~oo!vl ·.•.. ~· , Symbol:$ ~' 0 '-0" .,,, ~ /1 ~. Ah! I have deposited $100 and taken out $75, leaving me with a balance of$25! With Knowledge, make a decision Question: Can I buy a skateboard? Answer: No, the skateboard costs $75, which is more than my balance. Figure 1.3. Data-Information-Knowledge. Data is composed of the simple measurements around us, information is built out of an organization of data, and knowledge is built out of patterns in the information. By A. Debons, drawn by S. Masters. Introduction to Information 7 of this interaction (i.e., books, films, letters, etc.). We can understand this idea if we look at the many signs around us. Signs The way one can begin to understand information is through sensory experiences, the way information is presented in an environment. Signs provide examples of this concept (see figure 1.4). What are the sources of information in this picture? Try to count as many as possible on a separate sheet of paper. Now try to see if there is some grouping of the information into categories that make sense. Are all of these messages equally valuable? Are all of the messages true? Are all of the messages equally reliable? Is it possible for a lot of unimportant messages to crowd out the important information? Say that you were going to the Driver License Center; would it be important to you to know where Ambridge is? Clearly not. A lot of information is targeted at us in messages, which actively seek our attention, but some of it is passive and we must seek it out. Is there any natural, rather than man-made, information in the first picture? Can you tell the time of day, time of year, the weather, and the latitude? Now study figure 1.5. Since these signs are written in an unfamiliar language, how much information is there for you in this picture? This means that information is relative to the eye of the beholder. When we see a sign that says that the distance to a town is "20;' then how much time will it take to reach a town that is "20" away? What will that mean to somebody in Berlin as opposed to someone in New York? The -person in Berlin will think twenty kilometers, and the person in New York will Figure 1.4. Signs Are the Products of Our Brains. They help us to deal with the world around us. With permission of Ed Quigley, photographer. Figure 1.5. The Influence of Language on the Ability of Displays to Communicate. With permission of Ed Quigley, photographer. Introduction to Information 9 think twenty miles. Information is culturally based. This means that each group of people, wherever they are, use different words to label things around them or even use different languages to describe things around them. Our understanding of information is based on shared assumptions that vary from place to place. Characteristics of Information What are some characteristics of information? Some information is time sensitive. The food we buy at the grocery store often comes with a date stamped on it so we know when it will spoil. Most of the information in today's paper is outdated tomorrow. A billboard for a concert on July 10 contains little information on July I I. After a long while, however, bits of information will come back into the realm of importance. Historians and researchers may find that copy of the July IO newspaper and find it useful for studying our time period, making the information in that newspaper valuable again. The order in which you get information is also important. Imagine that you are trying to solve a problem, and an expert gives you some information that makes no sense to you. Later on, after becoming more familiar with the problem, you find one piece of information that sends you back to the earlier information that made no sense, and you can now understand it. This means that the order in which you receive information is important to your understanding of information. Information is a relative thing; its value is relative to the person who uses or requires it. For example, a user manual for a French camera that is written in French may contain all the information that a photographer needs, but if the photographer cannot read French, the information is useless. But if the photographer could read French, the information is very useful because that person can now use his or her camera to its fullest potential. Information can be explicit or tacit-that is, it can be clearly stated for anybody to use, or it can exist within the minds of a few people who share the information while not written down or available to outsiders. For example, you might obtain a guidebook that tells you how to behave at a Japanese restaurant; this is explicit information. On the other hand, if you went to a friend's house for Christmas, you may find yourself facing long-standing traditions, such as opening presents on Christmas Eve rather than Christmas Day. Information about these traditions is not readily available, so it is tacit information. Information and Communication Information and communication are two distinctly different things but are intertwined. Both are processes. When we communicate, we exchange Chapter 1 information; information, in some physical form, moves from the sender to the recipient. When we see, hear, smell, touch, and feel, we are receiving information about the world around us. There are invisible streams of information everywhere, many in the form of different wavelengths. The air is filled with AM, FM, and shortwave radio signals that we cannot recognize until an antenna catches them, and a device (such as a radio) decodes them for us. There are signals that contain information running in and out of the world's many cell phone towers. Information depends on communication for mobility and storage. The medium refers to the way the message or signal is moved from one place to another. When we send information through a medium, we are able to send it across distance and time. For example, say that you send e-mail to a friend in Florida; the information travels through the medium ( computers and the email system) and travels across time and space to reach your friend in Florida. When the spaceship Pioneer 10 was launched on a journey into deep space, the spaceship bore the plaque shown in figure 1.6. The designers of the plaque hoped that if any other life form in outer space found the spacecraft, they would be able to read the communication, in picture form, and gain information about humans. Communication is how we move information, and information is what is moved when we send a message. Without communication, information cannot move, and without information, communication has nothing to say. 0 • 0 0 • Figure 1.6. Plaque Carried by the Spaceship Pioneer 1 O. Source: www.aero spaceweb.org/question/spacecraft/q0225.shtml. Introduction to Information 11 Visible Information The information within our minds is invisible. Yes, there are devices that can scan our brains and develop information to make it visible for medical or research purposes. Still, no device yet invented can scan your brain to measure the quality or quantity of information that you have in it. But when you communicate a piece of information-either by voice, written message, or gesture-the information becomes observable, measurable, and recordable. This information is called visible information. Sometimes information can be visible to us, but we don't recognize it. In our failure to "see" or apprehend it, we remain uninformed. We are ignorant of the information before us. An example would be to place both a stereotypical city dweller and an expert at survival in the wilderness. The nature expert may see trees, rocks, and clouds, or may see animal tracks that the city dweller missed; he may see food that can be found and water that can be used. The nature expert may be able to anticipate weather. The expert and city dweller both "saw" the same world, but the expert was able to decode and interpret the signals in the environment, or "problem space." To be fair, if the situation were reversed and the city dweller and nature expert were set loose in Manhattan, the nature expert would be out of his field and would miss a lot of information picked up by the city dweller. Each of us sees the world in a way we wish to see it. Sometimes we miss the trees in the forest! Here's another example of visible information. Please examine the photograph in figure 1.7. The photo is of a statue honoring a long-dead general. Is there any other information that is available? Would your response be different if you knew that the sculptor who carved the statue used a widely accepted code to communicate the manner of the general's death? Well, that is exactly what happened. If the horse has one hoof in the air, the subject died of wounds received during battle. If the horse has two hooves in the air, the subject died in battle. And if the horse has all four hooves on the ground, the subject died a peaceful death. Now that you know the code of communication for the statue, more information is visible. A prerequisite to "seeing" a new situation is learning about what information is encoded in the situation-that is, learning the context of the situation. Variations on Decoding the Letter K The signals used to communicate meaning are not unique; in fact, the same signal can have very different meanings depending on the context of the sender and recipient. It can be visible to two people but have two very different meanings to each person. Consider a very simple signal that could be sent in a message: the letter K. Depending on who is sending the message, the letter K could 12 Chapter I Figure 1.7. Statue of Maj. Gen. John F. Reynolds. Source: www.virtual gettysburg.com/exhibit/monuments/pages/eq00S.html. have a wide variety of meanings. The same symbol is differently meaningful in each different context it is used. There are many examples: • A chemist recognizes K as the symbol for potassium in the periodic table. • A mapmaker using the metric system recognizes K as 10*!0*10, or 1000. • A computer designer recognizes K as 1024. • A person scoring a boxing match recognizes K as a knockout. • A pilot reading an aviation weather message recognizes K as smoke. • A baseball fan recognizes K as a strikeout. You can see that a message sent by the chemist to the sports writer could easily be misunderstood. These examples suggest that the symbol K itself has no meaning other than that which the sender and recipient mutually attach to it. The Philosophical Perspective Philosophy is the basic study of how we know things, matters of right and wrong, logic, and ideas and rules that come from studying it. Science has its basis in philosophical thought. Many philosophers from ancient times to the present have provided a way to look at information and knowledge. Aristotle's Introduction to Information 13 broad ideas of existence and the world have remained in the attention of thinkers for centuries. For our purpose, we will study Aristotle's interrogatives. His questions provide us with a sense of the relationship between information and knowledge. We will also examine Karl Popper's Three Worlds. His views help us put together our idea of data, information, and knowledge in our study of information science. Aristotle (384-322 BC) Aristotle (http://en.wikipedia.org/wiki/Aristotle), a student of Plato (http://en.wikipedia.org/wiki/Plato), was a Greek philosopher who contributed considerable amounts to our system of thinking, physics, biology, psychology, metaphysics, politics, rhetoric, and poetry. Aristotle divided the sciences into the rhetorical (the use of words) along with the practical and the productive. Aristotle also directed his attention to the role of questions in the development of categories of knowledge-a matter of some importance to our understanding of information and knowledge and, thus, to information science. Karl Popper (1902-1992) Like Aristotle, Karl Popper was a philosopher of science and a student of the scientific process. Popper (1965) describes a system of Three Worlds, which are very valuable as we try to discuss and understand information. Popper's worlds are shown in figure 1.8. Popper's World-! is the physical world, the world in which we live, which contains matter and energy, space, and time. World-2 is the realm of subjective reality, representing how we see the world from our own point of view, w-1 physical world w-3 objective knowledge Figure 1.8. Popper's Three Worlds. 14 Chapter 1 our personal reality. World-3 contains scientific knowledge, which is_ all of t_he accumulated knowledge we have gained through various interact10ns with recorded information. Popper's Three Worlds interact with each other. These Three Worlds are linked to each other through their interaction. This can be easy to understand and important to our study of information and information science. A World-2 observer, looking unto World-!, observes particular phenomena. Popper maintained that the activity of understanding consists of operating with World-3 objects. He described World-3 as an arena where ideas, expressed in language, can be critically discussed. Popper describes science as a process that takes place in his Three Worlds. Events happen in World-!. A person tries to make sense of them in World-2. When the person comes up with a theory that seems to explain the events, he introduces the theory to others in World-3. The community can accept or dispel the theory, and that evolutionary process is at the heart of science. How do we apply Popper's view and understanding of the world to our view of information and information science? Our minds bring the Three Worlds together by enabling us to respond to the physical states of matter and energy (World-I). This response we refer to as a state of awareness synonymous with information as a process (World-2). In the search for meaning, we conceive, create, design, and produce tools (technology) that add to our mental capacities. This technology helps us search, probe, and understand our inventiveness and creations (World-3). The business of information science is to find the connections between these Three Worlds. The approach is to identify the laws and principles that govern the environments of people, technology, and procedures we create that enable us to develop things, make decisions, and solve problems. Social Perspective Heidi and Alvin Tofjler Historians Heidi and Alvin Toffler (1984) have described human development as a series of revolutions they call the Three Waves. The First Wave was the agricultural revolution, when humans were farming. The Second Wave was the industrial revolution, when we began producing and working in factories. The Third Wave is the information revolution, when information became a mainstay of our economy. An easy way to remember the Three Waves is "farms, factories, and floppies.'' In the Tofflers' description, humans began as nomadic hunter-gatherers. People wandered in small bands in pursuit of food supplies. When the agriIntroduction to Information 15 cultural revolution began, people planted crops, tended the land, reaped the harvest, and stored the bounty throughout the year. When people started relying on farming for their existence, new problems started to arise and these problems needed new solutions. For instance, it became essential that clean water supplies be protected. Storehouses were built and notions of ownership were developed. Laws were generated and penalties were established for violations. The change from a hunter-gatherer society into a society of farmers was not painless. Roving bands of hunter-gatherers attacked early agricultural settlements. The farmers paid warlords to protect them, and local armies were developed. Farmers often did not own their own lands but worked as serfs for the warlords, paying a large share of their crops as tribute in a manner similar to paying taxes today. But the new life introduced by agriculture was an improvement and eventually became the way people lived in the First Wave. The tools used during the First Wave symbolized human strength: the knife, the blade for plowing, the lever, the inclined plane, and the wheel and axle. People in this era lived on the family farm. They rarely traveled and often spent their entire lives within the same few miles. People were generalists, able to do many things: tend crops, butcher animals, and make clothing and candles. For instance, once an animal had been slaughtered, the family would make use of almost every bit of the animal. Everyone in the family, regardless of age, performed the work that needed to be done. When a specialized product was built, it was built by hand. Today, these products are generated by small individualized manufacturing units as a cottage industry. In the 1500s, several forces brought about major changes to human culture. The Renaissance began an era of creativity and questioning of the status quo. The scientific revolution moved the questions of the Renaissance into the realm of the physical world. The Industrial Revolution brought the fruits of the scientific revolution into the workplace. The Second Wave was the Industrial Revolution. Man developed new materials such as iron and steel. We learned to exploit new sources of energy such as natural energy (wind and water) and chemical energy (coal and oil). The combination of the energy sources and the new metals allowed us to build machines that far exceeded the brute strength of animals. Examples include windmills, watermills, locomotives, and textile mills, which augmented our strengths to remarkable degrees. Work was done in factories, where specialized equipment was available. The factories required a large number of workers, so people left their farms and lived in homes outside the factories. The extended family broke down, and the nuclear family became dominant. In that nuclear family, the father often worked to make money, while the mother worked in the home. New social 16 Chapter 1 groups arose. Capitalists had the resources to invest in equipment and enjoyed the benefits of their investment. Laborers worked for an hourly wage paid m cash. Supervisors and managers oversaw the work of the laborers. None of these categories existed in the First Wave. In the First Wave, barter (trading goods such as crops for other goods or services) was the economic medium. Money replaced barter in the Second Wave. Investments were made in money. People were paid in cash wages. When the economy shifted into a money-focused system, the methods of taxation also shifted, and taxes on profits and wages were introduced. Real estate taxes are a First Wave phenomenon, and income taxes are a Second Wave phenomenon. In the Second Wave, work was done in factories, places with specialized machinery, specialized people, and specialized work. The change was not limited to the world of manufacturing. Schools were factories for learning. In the First Wave, learning and care were provided in the home, but with the Industrial Revolution, hospitals were created and they were factories for medical care. In the Second Wave, workers were no longer generalists; they became specialists, each trained only in one narrow technical skill. People left their farms to come to work in factories, and towns grew up around factories. The Industrial Revolution introduced a life of material wealth to the people living in Second Wave countries. The entire world did not simultaneously move into the Industrial Revolution; some parts of the world remained agricultural while others became industrial. For example, the American Civil War was about slavery and succession, but it was also a conflict between a Second Wave economy in the industrial North and a First Wave economy in the agricultural South. The transition from agriculture into industry saw its share of conflict. New technologies put many people out of work; one factory could produce more cloth than fifty cottage spindles. In France, workers threw their wooden shoes (sabot in French) into the machinery in protest, an act that gives us the word "sabotage." In England, people who opposed industrialization burned factories and equipment and honored an imaginary character named Ned Ludd as their leader. Today a person who resists technology is called a Luddite. As the Industrial Revolution progressed, companies and organizations became more complex. Huge businesses employed large numbers of people, on a scale previously seen only by large armies. The companies developed information systems to keep track of their business, their people, and their money. This was the birth of bureaucracy. Because work was concentrated in factories, people focused on the efficiency of work. This required greater capacity to be "on top,, of information needed and required for the management of resources, whether they be people or machines. The foundation of scientific management was born. Introduction to Information 17 The notion of the factory-a central repository of people, equipment, and activity-is not as crucial in the Third Wave. Information work does not have to be done in any particular location. For example, reports from New York, Los Angeles, and Singapore can be e-mailed to the headquarters in Chicago, posted on the Web for distribution, and can be read the same day in offices around the world. Location is not a crucial factor in the Third Wave. Neither is the office. In the Second Wave, the office represented the apex of the organization and the "middle manager" worked there. Large staffs of secretaries and typists prepared reports that were sent to the office where middle managers compiled and compared the reports, building summaries and forwarding the information to upper management. The function of middle management has been largely replaced by small personal computers (PCs) that do the work of these people. The Third Wave workers need the skills to handle, manage, and troubleshoot information systems. They need to be able to work with people of other disciplines. They need to manage their own careers. When technology changes (which it quite often does), they need to adapt to the new systems. Education is a lifelong process for Third Wave workers. Technological Perspective Vannevar Bush-Memex In the 1930s, Vannevar Bush had a vision that resembled modern computer systems. He called it Memex, which he noted as "a device in which an individual stores all his books, records, and communications, and which is mechanized so that it may be consulted with exceeding speed and flexibility" (Bush 1945). Bush envisioned a machine that made it easy to store and retrieve information. He wanted the information stored in a way that is uniform-that is, the same for each machine so that people will not have to relearn how to use the machine. Shannon and Weaver: Early Information Theory Warren Weaver described communications as "all of the procedures by which one mind can affect another" (1949, 1) and saw three different levels of communications problems: level A, the technical problem of communication; level B, the semantic problem of meaning; and level C, the effectiveness problem of changing conduct. The sections that follow explore Weaver's three levels of communication. Claude Shannon and Technical Communications Claude Shannon was an AT&T (telephone company) mathematician. He was primarily interested in 18 Chapter I using phone Jines to transfer signals and wondered what the cost of transferring information would be (Sveiby 1997). His first historic contribution was his recognition that transistors could be combined to perform as logical "gates:• moving Boolean algebra from the theoretical into the physical and permitting the construction of digital computers. Shannon is a fascinating figure; his mentor was Vannevar Bush, Franklin Roosevelt's World War II science czar. Shannon's second historic publication in 1948 (and republished with Weaver in 1949) was "A Mathematical Theory of Communication!' Shannon provided a communications model that dealt exclusively with Weaver's Level A, the technical problem of communication. Shannon was dealing with the wartime problem of radar signals and how a signal could be transmitted effectively in the presence of noise like static or interference. Please study figure 1.9 below. Shannon's communication model (involving an information source, transmitter, signal, noise, receiver, and destination) remains the accepted standard. In the picture that follows, an information source generates a message and gives it to a transmitter. The transmitter sends a signal, which is joined by noise known as static or interference. The received signal ( the original signal plus the noise) goes to the receiver, which decodes the message, and gives it to the destination. Please note that the information source and the destination can be people, devices, or systems. Figure 1.10 gives us an everyday example of this communications model. Consider Shannon's communications model in the process of sending a telegram. The sender generates a message to be sent and gives it to the telegraph operator, who generates a signal, which contains the message. The signal is sent over a network of wires that contains some static. At the other end, the receiving telegraph operator gets the signal, writes out the message, and gives it to the destination (the person to whom the telegram is addressed). INFORMATION SOURCE TRANSMITTER ~ SIGNAi MESSAGE L _, RECEIVED SIGNAi NOISE SOURCE RECEIVER DESTINATION '-- MESSAGE Figure 1.9. Communications Model: Transmitting a Signal in the Presence of Noise. "When I talk to you, my brain is the information source, yours the destination, my vocal system is the transmitter, and your ear ... the receiver." Source: Shannon (1948, 2). Hi! This is my dog Kate. Introduction to Information e c:, 0 19 Figure 1.10. Shannon's Communications Model. Drawn by S. Masters. Shannon's theory deals with transmission over a channel, minimizing noise and effective coding. Although many have labeled it an information theory, it is more accurately a communication theory, focused on Weaver's Level B, the semantic problem of meaning. For instance, for Shannon, the messages "CONSTANTINOPLE" and ")FUEJSHUHESEF" were identical from a communications perspective: they were each fourteen-character messages to be transmitted accurately. Another coded example is in figure 1.11 below. Weaver explicitly limited Shannon's use of the word "information" to a communications engineering perspective: "In particular, information must not be confused with meaning. In fact, two messages, one of which is heavily loaded with meaning and the other of which is pure nonsense, can be exactly equivalent, from the present viewpoint, as regards information" (Weaver 1949, 5). Checking the Accuracy of the Received Message Let's say that you are the pilot of a bomber, and you've received a message to drop a bomb at a particular map coordinate. These numbers represent the latitude and longitude of the target, and could be transmitted as two seven-character words: 0395248 0750111, which would translate into north 039 degrees 52 minutes 48 seconds, west 075 degrees 01 minutes 11 seconds. Message Key Cryptogram S ENDS U P PL I 1~ S • • • C O ME TS E- -N-D- S- tr 1' • • - USZHLMTCOA 1'11 Figure 1.11. Codes According to Shannon's Information Theory. 20 Chapter 1 Shannon's model describes a way for a message to be transmitted but really doesn't provide a way for the recipient to confirm the accuracy of the received message. It's important to be able to confirm the accuracy of a received message, especially when you're dropping bombs. Sometimes the transmission code employs a technique known as a checksum to confirm the accuracy of a received message. The way the checksum works is that the recipient adds up the first six digits of the message; the seventh digit should be equal to the rightmost digit of the summation. For instance, the original message is 0395248. The sum of all these characters (0 + 3 + 9 + 5 + 2 + 4 + 8) is 31. The rightmost character of 3 I is I. So we add a I to the right of the original sevendigit number as the checksum, and the transmitted number is 03952481. If the target coordinates were transmitted with a checksum, the transmitted message would be two eight-digit character words: 03952481 07501 I 15. The pilot who understood the checksum operation could then confirm the accuracy of the received message. See if you can use this process to validate the second coordinate, 07501 I 15. Is this a valid message? I OBSERVER -~ ;\-I SOURCE TRANSMITTER Figure 1.12. Using a Checksum. CORRECT!OX DATA I-+ M' RECEIVER ' CORRECTI'NGDEVICE Hi! This ismy dog Kate Introduction to Information ...... No Way! Her name is Kate! Figure 1.13. Errors Corrected by Feedback. Drawn by S. Masters. 21 In this example, when the destination receives the message, it sends another message back to the information source, saying either "Okay, I got that message, send me the next one" or "I didn't get that message correctly, please send it again." This addition to Shannon's basic model provides for a much more robust system that is more tolerant of interruptions, interference, and errors. This is illustrated in everyday life in figure 1.13, where the error created by noise from the dog is corrected with feedback. Shannon and Bits of Information Shannon also gave us one of the first quantifications of information: the bit, or binary digit. A bit is defined as a single digit in a binary number, either one or zero ("on" or "off"). For example, when we buy a floppy disk that holds 1.44 megabits, or a hard drive that stores 300 gigabits, we are using the new word that Shannon invented. Consider a person who lives on a houseboat and wants to be able to signal whether or not company is welcome to drop in for a visit. He rigs a light at the end of the dock. When the light is turned on, company is welcome; when it is off, company is not welcome. The signal device, the lightbulb, is capable of sending two different messages to people who know how to decode the message: welcome (on) and not welcome (off). Ifwe were to write a list of all the possible messages and then number the possible messages, it would look like figure 1.14. If more light bulbs were added, the numbers would look like figure 1.15. Shannon went one step further: he converted the numbers in the list to binary numbers and then counted the maximum numbers of binary digits necessary to carry all of the messages, as in the third column of figure 1.15. Message To Visitors Welcome! Not Welcome Light Bulb ON ~0::- OFF t figure 1.14. Possible Messages. Message To Host Expect 3 Visitors Expect 2 Visitors Expect 1 Visitor Expect No Visitors Light Bulbs Sets of 2 Units ON ~-o/-- ON ON ~-o/-- OFF OFF t ON OFF t OFF Code l 0 Code ~-o/-- 11 t 10 ~-o/-- 01 t 00 Figure 1.15. Shannon's conversion of the messages from numerical expression of expected visitors to binary digits (code). Introduction to Information 23 The largest number of digits required to count the messages in binary numbers is one binary digit, so Shannon would say that the message contains I bit of information. Here's another example: in Boston during the Revolutionary War, the colonists knew that the British were approaching in force but didn't know how they were comirig (by land or by sea). This was crucial information that needed to be disseminated quickly and accurately. Henry Wadsworth Longfellow's poem "Paul Revere's Ride'' immortalized this signal: "One if by land, and two ifby sea."When the information was available, one or two lights were displayed in the church tower, as shown in figure 1.16. Since the binary number for the last message contains two digits, Shannon's measure would say that this message contains 2 bits of information. Shannon said that information is the reduction of uncertainty and that the significant aspect of information is that it is one message selected from a set of possible messages. He explained that the number of bits of information in a message (H) could be calculated by H = log2(x), where x equals the number of equal probable messages from which it could be selected. Systems Theory and Cybernetics Let's say that your favorite baseball team just won the World Series and are the champions. Some claim that the reason for their win lies in the players' skills, but the other team has expert players as well. What could the difference be? A systems theorist would say that the team's organization (how the team was put together) led to the successful season. They would say that the overall organization of these expert players was the difference that gave them the edge against the other team. A system can be anything from a computer system to a baseball team to a coding scheme for libraries (such as the Dewey decimal system). American Message One if by Land Two if by Sea Lanterns Figure 1.16. Paul Revere's signals conceptualized. Drawn by S. Masters. 24 Chapter I A system is anything that has organization of parts that are put together to achieve a certain purpose. Systems theory attempts to determine the principles that bring objects and processes together in achieving their objectives. Many of the ideas associated with systems theory came from cybernetics, a word first used by Norbert Wiener (1894--1964). Cybernetics means "the sci. ence of systems of control and communications in animals and machines>) (Wiener, 1948). Wiener used many ideas from Shannon's information theory, which we discussed previously. The idea of feedback was of specific impor• tance to cybernetic system thinking. Many organisms and parts thereof live in the world of feedback. We eat and our hunger subsides. A student passes an examination and a grade is given that rewards the student's effort. Feedback is the key to Shannon's information theory. The idea of feedback is not as simple as it sounds. Much has been and continues to be studied about feedback. For our current understanding, it is sufficient to be alert to the role that cybernetics plays in our study of information science. To the extent that one of the major functions of the information scientist is to analyze, design, and evaluate data, information, and knowledge systems> cybernetics serves as an im~ portant foundation to the science. A distinction between the two theories is this: systems theory has focused on the structure of a system, how it is laid out and organized. Cybernetics, however, focuses more on the function of the system, how actions are controlled and how the system communicates with other systems as well as its own parts. The ideas of systems and feedback were used heavily in World War II. The machines of the Industrial Age became more complex and specialized. Military operations have always required information systems to command and control the resources for battle. Thus, the first modern information system came out of the military. The early computers were built to compute ballistic tables for gunnery. We built radar systems that let an operator "see" ships and planes sooner. We have always had information, but in World War II we started using information in new ways, even if written down. We built machines and systems that moved information just like factories moved physical goods. As the Cold War developed, we built command-and-control systems such as NORAD and the DEW line. These helped manage complexities that no one person could hold in his or her brains. These systems and the feedback they produced were vital in helping the United States engage in military operations. These facilities replaced human lookouts at the fringe of a position with radar and other sensors, augmenting our capacity to observe threats. They also augmented the awareness of local military commanders, permitting one facility to deal with a strategic picture that no one individual could understand. Introduction to Information 25 SUMMARY fundamental property of life. No one on earth can live with• n is all around us, in all the physical things that meet our ther sensors within the body. Information is also in our heads, ' accepts and uses (processes) all that happens around us. our understanding of information-both as process and d present, which combine information together with knowlbles us to view the nature of questions (interrogatives), how • their importance to our understanding of information and opper provides us with a broad view of information as reworld around us, that which we all bring to this world and we create (engineer and produce) to bring these two worlds s. Our understanding and attention to information are also ·strides that science and engineering have made to enable us and communicate information. We see this in the rapid degineering of computers and other technologies ( electronic er optics) that enable us to send and receive messages d others (the Third Wave). Among these advances is our • ormation (Shannon's bits) and develop systems that can lems and make decisions. It's within all this that we can d information science as the integrator of each of these as- EXERCISES to say that something is not information? Explain. t by the statement that information is in one's head or js stated that information is a process. What can this idea ~ an example. that you have faced and discuss the role that informathe problem and how it helped you understand the imormation. n and Warren Weaver were two important scientists that we transmit information. How did Shannon's thinking ees? Discuss their similarities and differences. that you wanted to convey a message to one of your . i1 would not want others to receive. How would you de-- achieve such an objective? 26 Chapter 1 7. What is the difference between transmitting and communicating information? What is the importance of this difference? 8. What is meant by visible information? Provide an example. 9. Discuss the idea of feedback. What importance does the idea of feedback serve in our understanding of information? 10. What is meant by reduction of uncertainty? Discuss the relationship between data, information, and knowledge.