HCI-lect -01_merged.pdf

HCI Lecture One 1  Reference ALAN DIX, JANET FINLAY, GREGORY D. ABOWD, RUSSELL BEALE THIRD EDITION HUMAN–COMPUTER INTERACTION 2  WHAT IS HCI? The term human–computer interaction has only been in widespread us...

HCI Lecture One 1  Reference ALAN DIX, JANET FINLAY, GREGORY D. ABOWD, RUSSELL BEALE THIRD EDITION HUMAN–COMPUTER INTERACTION 2  WHAT IS HCI? The term human–computer interaction has only been in widespread use since the early 1980s, but has its roots in more established disciplines. Systematic study of human performance began in earnest at the beginning of the last century in factories, with an emphasis on manual tasks. 3  WHAT IS HCI? The Second World War provided the force for studying the interaction between humans and machines, as each side strove )‫ (جاهد‬to produce more effective weapons systems. As computer use became more widespread, an increasing number of researchers specialized in studying the interaction between people and computers. 4  WHAT IS HCI? HCI draws on many disciplines, but it is in computer science and systems design that it must be accepted as a central concern. HCI involves the design, implementation and evaluation of interactive systems in the context of the user’s task and work. 5  WHAT IS HCI? However, when we talk about human–computer interaction, we do not necessarily imagine a single user with a desktop computer. By user we may mean an individual user, a group of users working together, or a sequence of users in an organization, each dealing with some part of the task or process. The user is whoever is trying to get the job done using the technology. 6  WHAT IS HCI? By computer we mean any technology ranging from the general desktop computer to a large- scale computer system, a process control system or an embedded system. The system may include non-computerized parts, including other people. By interaction we mean any communication between a user and computer, be it direct or indirect. 7  THEORY AND HCI Unfortunately for us, there is no general and unified theory of HCI that we can present. Indeed, it may be impossible ever to derive one; it is certainly out of our reach today. However, there is an underlying principle that forms the basis of our own views on HCI, and it is captured in our claim that people use computers to accomplish work. 8  THEORY AND HCI This outlines the three major issues of concern: the people, the computers and the tasks that are performed. The system must support the user’s task, which gives us a fourth focus, usability: if the system forces the user to adopt an unacceptable mode of work then it is not usable. 9  THEORY AND HCI This word ‘task’ or the focus on accomplishing ‘work’ is also problematic when we think of areas such as domestic appliances, consumer electronics and e-commerce. There are three ‘use’ words that must all be true for a product to be successful; it must be: 10  THEORY AND HCI Useful: accomplish what is required: play music, cook dinner, format a document. Usable: do it easily and naturally, without danger of error, etc. Used: make people want to use it, be attractive, engaging, fun, etc. 11 Thank You 12  HCI Lecture 02 1  INTRODUCTION We start with the human, the central character in any discussion of interactive systems. The human, the user, is the one whom computer systems are designed to assist. The requirements of the user should therefore be our first priority. 2  INTRODUCTION In order to design something for someone, we need to understand their capabilities and limitations. We need to know if there are things that they will find difficult or, even, impossible. We will look at aspects of cognitive )‫(ادراكى‬psychology which have a bearing )‫(تحمل‬ on the use of computer systems: 3  INTRODUCTION how humans perceive the world around them, how they store and process information and solve problems, and how they physically manipulate objects. In 1983, Card, Moran and Newell described the Model, Human Processor Model, which is a simplified view of the human processing involved in interacting with computer systems. The model comprises three subsystems: 4  INTRODUCTION – the perceptual system ) ‫(نظاا االدراكداالدسى اا‬, handling sensory stimulus )‫ (التحفيز‬from the outside world, – the motor system ) ‫(دسنظااا االدسىك ااا‬, which controls actions, – the cognitive system) ‫(النظ ا الالمفر ا‬, which provides the processing needed to connect the perceptual system and the motor system. Each of these subsystems has its own processor and memory, although obviously the complexity of these varies depending on the complexity of the tasks the subsystem has to perform. 5  INTRODUCTION The model also includes a number of principles of operation which dictate the behavior of the systems under certain conditions. We will use the analogy of the user as an information processing system, but in our model make the analogy closer to that of a conventional )‫(تقليدى‬computer system. Information comes in, is stored and processed, and information is passed out. We will therefore discuss three components of this system: input–output, memory and processing. 6  INTRODUCTION In the human, we are dealing with an intelligent information-processing system, and processing therefore includes problem solving, learning, and, consequently, making mistakes. In this lecture, we will first look at the human’s input–output channels, the senses and responders or effectors. 7  INTRODUCTION In other lectures, we will consider human memory and how it works. We will then think about how humans perform complex problem solving, how they learn and acquire skills, and why they make mistakes. Finally, we will discuss how these things can help us in the design of computer systems. 8  INPUT–OUTPUT CHANNELS A person’s interaction with the outside world occurs through information being received and sent: input and output. In an interaction with a computer the user receives information that is output by the computer, and responds by providing input to the computer. Input in the human occurs mainly through the senses and output through the motor control of the effectors. 9  INPUT–OUTPUT CHANNELS There are five major senses: sight )‫ (البصر‬, hearing, touch, taste and smell. Of these, the first three are the most important to HCI. Taste and smell do not currently play a significant role in HCI. However, vision, hearing and touch are central. Similarly there are a number of effectors, including the limbs )‫(اطراف‬, fingers, eyes, head and vocal )‫ (الصوت‬system. 10  INPUT–OUTPUT CHANNELS In the interaction with the computer, the fingers play the primary role, through typing or mouse control, with some use of voice and eye, head and body position. Imagine using a personal computer (PC) with a mouse and a keyboard. The application you are using has a graphical interface, with menus, icons and windows. In your interaction with this system you receive information primarily by sight, from what appears on the screen. 11  INPUT–OUTPUT CHANNELS However, you may also receive information by ear: for example, the computer may ‘beep’ at you if you make a mistake or to draw attention to something, or there may be a voice commentary in a multimedia presentation. Touch plays a part in that you will feel the keys moving (also hearing the ‘click’) or the orientation of the mouse, which provides vital feedback about what you have done. 12  INPUT–OUTPUT CHANNELS You yourself send information to the computer using your hands, either by hitting keys or moving the mouse. Sight and hearing do not play a direct role in sending information in this example, although they may be used to receive information from a third source (for example, a book, or the words of another person) which is then transmitted to the computer. 13  INPUT–OUTPUT CHANNELS In this section we will look at the main elements of such an interaction, first considering the role and limitations of the three primary senses and going on to consider motor control. 14  Vision Human vision is a highly complex activity with a range of physical and perceptual limitations, yet it is the primary source of information for the average person. We can roughly divide visual perception into two stages: – The physical reception of the stimulus from the outside world. – The processing and interpretation of that stimulus. 15  Vision On the one hand the physical properties of the eye and the visual system mean that there are certain things that cannot be seen by the human. On the other the interpretative capabilities of visual processing allow images to be constructed from incomplete information. 16  The human eye We will begin by looking at the eye as a physical receptor, and then go on to consider the processing involved in basic vision. – Vision begins with light. The eye is a mechanism for receiving light and transforming it into electrical energy. – Light is reflected from objects in the world and their image is focused upside down on the back of the eye. – The receptors in the eye transform it into electrical signals which are passed to the brain. 17  Visual perception Understanding the basic construction of the eye goes some way to explaining the physical mechanisms of vision but visual perception is more than this. CLICK HERE 18  Visual perception we will look a little more closely at how we perceive size and depth, brightness and color, each of which is crucial to the design of effective visual interfaces. 19  Perceiving size and depth Imagine you are standing on a hilltop. Beside you on the summit you can see rocks, sheep and a small tree. On the hillside is a farmhouse with outbuildings and farm vehicles. Someone is on the track, walking toward the summit. Below in the valley is a small market town. Our visual system is easily able to interpret the images which it receives to take account of these things. We can identify similar objects regardless of the fact that they appear to us to be of vastly different sizes. In fact, we can use this information to judge distances. 20  Perceiving size and depth So how does the eye perceive size, depth and relative distances? To understand this we must consider how the image appears on the retina )‫(شبكةلالفين‬. As we noted in the previous section, reflected light from the object forms an upside-down image on the retina. The size of that image is specified as a visual angle. Figure 1.2 illustrates how the visual angle is calculated. 21 22  Perceiving size and depth If we were to draw a line from the top of the object to a central point on the front of the eye and a second line from the bottom of the object to the same point, the visual angle of the object is the angle between these two lines. Visual angle is affected by both the size of the object and its distance from the eye. Therefore if two objects are at the same distance, the larger one will have the larger visual angle. Similarly, if two objects of the same size are placed at different distances from the eye. 23  Perceiving brightness A second aspect of visual perception is the perception of brightness. Brightness is in fact a subjective reaction to levels of light. It is affected by luminance )‫ (االن رة‬which is the amount of light emitted )‫(منبفث‬by an object. 24  Perceiving brightness Luminance is a physical characteristic and can be measured using a photometer. Contrast )‫ (تن قض‬is related to luminance: it is a function of the luminance of an object and the luminance of its background. Visual acuity )‫ (ىاةالدسبصك‬increases with increased luminance. This may be an argument for using high display luminance. However, as luminance increases, flicker )‫(رمش‬also increases. The eye will perceive a light switched on and off rapidly as constantly on. 25  Perceiving color A third factor that we need to consider is perception of color. Color is usually regarded as being made up of three components: hue)‫(درجةلاللون‬, intensity )‫ (الشدة‬and saturation )‫(التشبع‬. Hue is determined by the spectral)‫(طيفى‬ wavelength of the light. Blues have short wavelengths, greens medium and reds long. 26  Perceiving color Approximately 150 different hues can be discriminated by the average person. Intensity is the brightness of the color. Saturation is the amount of whiteness in the color. By varying these two, we can perceive in the region of 7 million different colors. 27  The capabilities and limitations of visual processing In considering the way in which we perceive images we have already encountered some of the capabilities and limitations of the human visual processing system. Visual processing involves the transformation and interpretation of a complete image, from the light that is thrown onto the retina. 28  The capabilities and limitations of visual processing This ability to interpret and exploit our expectations can be used to resolve ambiguity )‫(التب س‬. For example, consider the image shown in Figure 1.3. What do you perceive? Now consider Figure 1.4 and Figure 1.5. 29 The capabilities and limitations of visual processing 30 The capabilities and limitations of visual processing 31 32 The capabilities and limitations of visual processing 33 The capabilities and limitations of visual processing 34  The capabilities and limitations of visual processing However, it can also create optical illusions. For example, consider Figure 1.6. Which line is longer? Most people when presented with this will say that the top line is longer than the bottom. In fact, the two lines are the same length. This may be due to a false application of the law of size constancy: the top line appears like a concave edge, the bottom like a convex edge. A similar illusion is the Ponzo illusion (Figure 1.7). Here the top line appears longer, owing to the distance effect, although both lines are the same length. These illusions )‫(أوه ال‬demonstrate that our perception of size is not completely reliable. 35 The capabilities and limitations of visual processing 36 Thank you 37  HCI LECTURE 03 1  Hearing The sense of hearing is often considered secondary to sight, but we tend to underestimate the amount of information that we receive through our ears. Close your eyes for a moment and listen. – What sounds can you hear? – Where are they coming from? – What is making them? 2  Hearing As I sit at my desk I can hear cars passing on the road outside, machinery working on a site nearby, the drone of a plane overhead and bird song. But I can also tell where the sounds are coming from, and estimate how far away they are. from the sounds I hear I can tell that a car is passing on a particular road near my house, and which direction it is traveling in. The auditory system can convey a lot of information about our environment. But how does it work? 3  The human ear hearing begins with vibrations in the air or sound waves. The ear receives these vibrations and transmits them, through various stages, to the auditory nerves )‫(االعصاب السمعية‬. The ear comprises three sections, commonly known as the outer ear, middle ear and inner ear. 4  The human ear The outer ear is the visible part of the ear. It has two parts: the pinna, which is the structure that is attached to the sides of the head, and the auditory canal, along which sound waves are passed to the middle ear. The outer ear serves two purposes. First, it protects the sensitive middle ear from damage. – The auditory canal contains wax )‫ (شمع‬which prevents dust, dirt and over-inquisitive insects )‫ (الحشرات‬reaching the middle ear. Secondly, the pinna and auditory canal serve to amplify some sounds. 5  The human ear The middle ear is a small cavity )‫ (تجويف‬connected to the outer ear by the tympanic membrane)‫(الغشاء الطبلى‬, or ear drum )‫(طبلة االذن‬, and to the inner ear by the cochlea )‫(القوقعة‬. Within the cavity are the ossicles )‫(عظيمات‬, the smallest bones in the body. Sound waves pass along the auditory canal and vibrate the ear drum which in turn vibrates the ossicles )‫(عظيمات‬, which transmit the vibrations to the cochlea, and so into the inner ear. ‫(الموجات الصوتية تمر على طول القناة السمعية وتهتز طبلة األذن التي‬ ‫ التي تنقل االهتزازات إلى قوقعة‬،)‫بدورها يهتز على عظيمات (عظيمات‬ ).‫ وذلك في األذن الداخلية‬،‫األذن‬ 6  The human ear the inner ear is filled with a denser cochlean liquid (‫)سائل مكثف اى الخاليا الشعيرية‬. By transmitting them via the ossicles the sound waves are concentrated and amplified. ‫( بارسال الموجات عبر عظيمات تتركز موجات الصوت‬ )‫وتضخيمه‬ 7  The human ear The waves are passed into the liquid-filled cochlea in the inner ear. Within the cochlea are delicate hair cells or cilia that bend because of the vibrations in the cochlean liquid and release a chemical transmitter which causes impulses in the auditory nerve. ‫ (داخل القوقعة خاليا الشعر الحساسة أو أهداب أن تنحني بسبب‬ ‫االهتزازات في السائل من ثم ارسال اشارات الكيميائى التى تسبب‬ ).‫النبضات في العصب السمعي‬ 8  Processing sound As we have seen, sound is changes or vibrations in air pressure. It has a number of characteristics which we can differentiate. Pitch (tone ‫ )نغمة‬is the frequency of the sound. A low frequency produces a low pitch, a high frequency, a high pitch. Loudness is proportional to the amplitude )‫(سعة‬ of the sound; the frequency remains constant. Timbre )‫(جرس‬relates to the type of the sound 9  Processing sound The human ear can hear frequencies from about 20 Hz to 15 kHz. The auditory system performs some filtering of the sounds received, allowing us to ignore background noise and concentrate on important information. > 10  Touch The third and last of the senses that we will consider is touch or haptic perception. Although this sense is often viewed as less important than sight or hearing, imagine life without it. Touch provides us with vital information about our environment. It tells us when we touch something hot or cold, and can therefore act as a warning. >> 11  Touch It also provides us with feedback when we attempt to lift an object, for example. Consider the act of picking up a glass of water. If we could only see the glass and not feel when our hand made contact with it or feel its shape, the speed and accuracy of the action would be reduced. 12  Touch The apparatus of touch differs from that of sight and hearing in that it is not localized. We receive stimuli through the skin. The skin contains three types of sensory receptor: – thermoreceptors respond to heat and cold. – nociceptors respond to intense pressure and pain. – mechanoreceptors respond to pressure. 13  Touch There are two kinds of mechanoreceptor, which respond to different types of pressure. Rapidly adapting mechanoreceptors respond to immediate pressure as the skin is indented. These receptors also react more quickly with increased pressure. However, they stop responding if continuous pressure is applied. Slowly adapting mechanoreceptors respond to continuously applied pressure. 14 Thank You 15  HCI Lecture 04 1  Movement Before leaving this section on the human’s input–output channels, we need to consider motor control and how the way we move affects our interaction with computers. A simple action such as hitting a button in response to a question involves a number of processing stages. The stimulus (of the question) is received through the sensory receptors and transmitted to the brain. The question is processed and a valid response generated. The brain then tells the appropriate muscles (‫)العضالت‬to respond. Each of these stages takes time, which can be roughly divided into reaction time and movement time. 2  Movement Movement time is dependent largely on the physical characteristics of the subjects: their age and fitness. Reaction time varies according to the sensory channel through which the stimulus is received. A person can react to an auditory signal in approximately 150 ms, to a visual signal in 200 ms and to pain in 700 ms. 3  Movement However, a combined signal will result in the quickest response. Factors such as skill or practice can reduce reaction time, and fatigue )‫ (التعب‬can increase it. A second measure of motor skill is accuracy. This is dependent on the task and the user. In some cases, requiring increased reaction time reduces accuracy. 4  Movement Speed and accuracy of movement are important considerations in the design of interactive systems, primarily in terms of the time taken to move to a particular target on a screen. The target may be a button, a menu item or an icon, for example. The time taken to hit a target is a function of the size of the target and the distance that has to be moved. 5  HUMAN MEMORY Have you ever played the memory game? The idea is that each player has to recount a list of objects and add one more to the end. Indeed, much of our everyday activity relies on memory. As well as storing all our factual knowledge, our memory contains our knowledge of actions or procedures. It allows us to repeat actions, to use language, and to use new information received via our senses. It also gives us our sense of identity, by preserving information from our past experiences. 6  HUMAN MEMORY – But how does our memory work? – How do we remember arbitrary lists such as those generated in the memory game? – Why do some people remember more easily than others? – what happens when we forget? In order to answer questions such as these, we need to understand some of the capabilities and limitations of human memory. 7  HUMAN MEMORY Memory is the second part of our model of the human as an information-processing system. memory is associated with each level of processing. Bearing this in mind, we will consider the way in which memory is structured and the activities that take place within the system. 8  HUMAN MEMORY It is generally agreed that there are three types of memory or memory function: sensory buffers: (The sensory memories act as buffers for stimuli received through the senses.) short-term memory or working memory: (acts as a ‘scratch-pad’ for temporary recall of information. It is used to store information which is only required fleetingly)‫)(عابرة‬ long-term memory: (is our working memory or ‘scratch-pad’, long-term memory is our main resource. Here we store factual information, experiential knowledge, procedural rules of behavior – in fact, everything that we ‘know’) 9  HUMAN MEMORY It differs from short-term memory in a number of significant ways. First, it has a huge and unlimited capacity. Secondly, it has a relatively slow access time of approximately a tenth of a second. Thirdly, forgetting occurs more slowly in long- term memory. 10  Long-term memory processes There are three main activities related to long-term memory: storage or remembering of information, forgetting and information retrieval. First, how does information get into long-term memory and how can we improve this process? Information from short-term memory is stored in long-term memory by rehearsal(‫)بروفة‬. 11  Long-term memory processes what causes us to lose this information, to forget? There are two main theories of forgetting: decay)‫(تسوس‬ and interference. The first theory suggests that the information held in long-term memory may eventually be forgotten. The second theory is that information is lost from memory through interference. A common example of this is the fact that if you change telephone numbers, learning your new number makes it more difficult to remember your old number. This is because the new association masks the old. 12  Long-term memory processes The third process is information retrieval. Here we need to distinguish between two types of information retrieval, recall and recognition. In recall the information is reproduced from memory. In recognition, the presentation of the information provides the knowledge that the information has been seen before. Recognition is the less complex cognitive)‫(ادراك‬ activity since the information is provided as a cue)‫(لمح‬. 13  THINKING: REASONING AND PROBLEM SOLVING We have considered how information finds its way into and out of the human system and how it is stored. Finally, we come to look at how it is processed and manipulated. We are able to think about things of which we have no experience, and solve problems which we have never seen before. How is this done? 14  THINKING: REASONING AND PROBLEM SOLVING Thinking can require different amounts of knowledge. Some thinking activities are very directed and the knowledge required is constrained. In this section we will consider two categories of thinking: reasoning and problem solving. 15  THINKING: REASONING AND PROBLEM SOLVING Reasoning: Reasoning )‫(المنطق‬is the process by which we use the knowledge we have to draw conclusions or infer)‫ (اإلستنباط‬something new about the domain of interest. There are a number of different types of reasoning: deductive)‫(استنتاجي‬, inductive)‫(استقرائية‬ and abductive. We use each of these types of reasoning in everyday life, but they differ in significant ways. 16  THINKING: REASONING AND PROBLEM SOLVING Deductive reasoning: Deductive reasoning derives the logically necessary conclusion from the given premises)‫(معطيات او دالالت‬. For example, If it is Saturday then she will go to work. Inductive reasoning: Induction is generalizing from cases we have seen to infer information about cases we have not seen. For example, if every elephant we have ever seen has a trunk, we infer that all elephants have trunks. 17  THINKING: REASONING AND PROBLEM SOLVING Abductive reasoning: The third type of reasoning is abduction. Abduction reasons from a fact to the action or state that caused it. This is the method we use to derive explanations for the events we observe. For example, suppose we know that Sam always drives too fast when he has been drinking. If we see Sam driving too fast we may infer that he has been drinking. 18  THINKING: REASONING AND PROBLEM SOLVING Problem solving If reasoning is a means of inferring new information from what is already known, problem solving is the process of finding a solution to an unfamiliar task, using the knowledge we have. There are a number of different views of how people solve problems. 19  THINKING: REASONING AND PROBLEM SOLVING Gestalt theory Gestalt psychologists were answering the claim, made by behaviorists, that problem solving is a matter of reproducing known responses or trial and error. 20  THINKING: REASONING AND PROBLEM SOLVING Problem space theory Newell and Simon proposed that problem solving centers on the problem space. The problem space comprises problem states, and problem solving involves generating these states using legal state transition operators. The problem has an initial state and a goal state and people use the operators to move from the former to the latter. 21  PSYCHOLOGY AND THE DESIGN OF INTERACTIVE SYSTEMS So far we have looked briefly at the way in which humans receive, process and store information and solve problems. But how can we apply what we have learned to designing interactive systems? For example, we can deduce that recognition is easier than recall and allow users to select commands from a set (such as a menu) rather than input them directly. 22 Thank You 23  HCI Lecture Five 1  Introduction In order to understand how humans interact with computers, we need to have an understanding of both parties in the interaction. The previous lectures explored aspects of human capabilities and behavior of which we need to be aware in the context of human–computer interaction; this chapter considers the computer and associated input–output devices and investigates how the technology influences the nature of the interaction and style of the interface. 2  Introduction When we interact with computers, what are we trying to achieve? Consider what happens when we interact with each other – we are either passing information to other people, or receiving information from them. Interaction is therefore a process of information transfer. Relating this to the electronic computer, the same principles hold: interaction is a process of information transfer, from the user to the computer and from the computer to the user. 3  What Is Input? Input is any data and instructions entered into the memory of a computer 4  What Is Input? Instructions can be entered into the computer in the form of programs, commands, and user responses A program is a series of related instructions that tells a computer what tasks to perform and how to perform them Programs respond to commands that a user issues A user response is an instruction a user issues by replying to a question displayed by a program 5 What Are Input Devices An input device is any hardware component that allows users to enter data and instructions into a computer 6  The Keyboard A keyboard is an input device that contains keys users press to enter data and instructions into a computer 7  The Keyboard Most desktop computer keyboards have… 8  The Keyboard The insertion point, also known as the cursor, is a symbol on the screen that indicates where the next character you type will appear 9  The Keyboard Wired Wireless Keyboards Keyboards USB port Bluetooth Keyboard IrDA port 10  The Keyboard Keyboards on mobile devices typically are smaller and/or have fewer keys Some phones have predictive text input, which saves time when entering text using the phone’s keypad 11 Pointing Devices 12  Mouse A mouse is a pointing device that fits under the palm of your hand comfortably – Most widely used pointing device on desktop computers A mouse can be wired or wireless 13  Mouse Mouse operations Point Click Right-click Double-click Rotate Triple-click Drag Right-drag wheel Free-spin Press thumb Press wheel Tilt wheel wheel button 14  Other Pointing Devices Pointing Stick Trackball Touchpad A trackball is a A touchpad is A pointing stationary a small, flat, stick is a pointing rectangular pressure- device with a pointing sensitive ball on its top device that is pointing or side sensitive to device shaped pressure and like a pencil motion eraser that is positioned between keys on a keyboard 15  Touch Screens and Touch-Sensitive Pads A touch screen is a touch-sensitive display device 16  Pen Input With pen input, you touch a stylus or digital pen on a flat surface to write, draw, or make selections 17  Game Controllers Video games and computer games use a game controller as the input device that directs movements and actions of on-screen objects Joysticks and Gamepads Light guns Wheels Motion- Dance pads sensing controllers 18 Game Controllers 19  Digital Cameras A digital camera is a mobile device that allows users to take pictures and store them digitally 20  Digital Cameras Two factors affect the quality of digital camera photos: Resolution is the number of horizontal and vertical pictures in a display device Resolution A pixel is the smallest element in an electronic display Number of bits Each pixel consists of one or more bits of data stored in each The more bits used to represent a pixel, the more colors and shades of gray that pixel can be represented 21  Voice Input Voice input is the process of entering input by speaking into a microphone Voice recognition is the computer’s capability of distinguishing spoken words 22  Voice Input Audio input is the process of entering any sound into the computer Speech Music Sound Effects 23  Voice Input Music production software allows users to record, compose, mix, and edit music and sounds 24  Video Input Video input is the process of capturing full-motion images and storing them on a computer’s storage medium Record video on a digital video (DV) camera or use a video capture card to convert analog signals to digital Connect the camera to a port on the system unit Transfer video and images 25 Video Input 26  Video Input A Web cam is a type of digital video camera that enables a user to: Send e-mail Capture video and Add live images to messages with still images instant messages video attachments Broadcast live Make video images over the telephone calls Internet 27  Video Input A video conference is a meeting between two or more geographically separated people 28 Scanners and Reading Devices 29 Scanners and Reading Devices A bar code reader, also called a bar code scanner uses laser beams to read bar codes 30  Scanners and Reading Devices Magnetic stripe card readers read the magnetic stripe on the back of cards such as: Credit cards Entertainment cards Bank cards Other similar cards 31  Scanners and Reading Devices MICR (magnetic ink character recognition) devices read text printed with magnetized ink An MICR reader converts MICR characters into a form the computer can process Banking industry uses MICR for check processing 32  Biometric Input Biometrics authenticates a person’s identity by verifying a personal characteristic Face Hand Fingerprint recognition geometry reader system system Voice Signature Iris recognition verification verification system system system Retinal scanners 33 Thank You  HCI LECTURE 06 1  What Is Output? Output is data that has been processed into a useful form 2  What Is Output? An output device is any type of hardware component that conveys information to one or more people Speakers, Display devices Printers headphones, Data projectors and earbuds Force-feedback Interactive game Tactile output whiteboards controllers 3  Display Devices A display device visually conveys text, graphics, and video information A monitor is packaged as a separate peripheral – LCD monitor – Widescreen 4  Display Devices Liquid crystal display (LCD) uses a liquid compound to present information on a display device 5  Display Devices An active-matrix display, also known as a TFT (thin-film transistor) display, uses a separate transistor to apply charges to each liquid crystal cell and thus displays high-quality color that is viewable from all angles. 6  Display Devices A passive-matrix display uses fewer transistors, requires less power, and is less expensive than an active-matrix display. The color on a passive-matrix display often is not as bright as an active-matrix display. 7  Display Devices Plasma monitors are display devices that use gas plasma technology and offer screen sizes up to 150 inches 8  Display Devices Televisions also are a good output device – Require a converter if you are connecting your computer to an analog television Digital television (DTV) offers a crisper, higher- quality output HDTV is the most advanced form of digital television 9  Printers A printer produces text and graphics on a physical medium – Printed information is called a hard copy, or printout – Landscape or portrait orientation 10  Printers High- speed Black- and- Laser High- quality white printer Color 11  Printers A multifunction peripheral (MFP) is a single device that prints, scans, copies, and in some cases, faxes – Sometimes called an all-in-one device 12  Printers A mobile printer is a small, lightweight, battery-powered printer that allows a mobile user to print from a mobile device 13  Printers Plotters are used to produce high-quality drawings Large-format printers create photo-realistic quality color prints on a larger scale 14  Speakers, Headphones, and Earbuds An audio output device produces music, speech, or other sounds Most computer users attach speakers to their computers to: Generate higher-quality sounds for playing games Interact with multimedia presentations Listen to music View movies 15  Speakers, Headphones, and Earbuds Headphones are speakers that cover your head or are placed outside of the ear Earbuds (also called earphones) rest inside the ear canal 16  Other Output Devices A data projector is a device that takes the text and images displaying on a computer screen and projects them on a larger screen – Digital light processing (DLP) projector 17  Other Output Devices An interactive whiteboard is a touch-sensitive device, resembling a dry-erase board, that displays the image on a connected computer screen 18 Memory 19  Memory Memory consists of electronic components that store instructions waiting to be executed by the processor, data needed by those instructions, and the results of processing the data Stores three basic categories of items: Data being The operating Application processed and the system and other programs resulting system software information 20  Memory Each location in memory has an address Memory size is measured in kilobytes (KB or K), megabytes (MB), gigabytes (GB), or terabytes (TB) 21  Memory The system unit contains two types of memory: Volatile memory Nonvolatile memory Loses its contents when Does not lose contents power is turned off when power is removed Examples include ROM, Example includes RAM flash memory, and CMOS 22  Memory Three basic types of RAM chips exist: Dynamic RAM Magnetoresistive Static RAM (SRAM) (DRAM) RAM (MRAM) 23  Memory RAM chips usually reside on a memory module and are inserted into memory slots 24  Memory The amount of RAM necessary in a computer often depends on the types of software you plan to use 25  Memory Memory cache speeds the processes of the computer because it stores frequently used instructions and data 26  Memory Read-only memory (ROM) refers to memory chips storing permanent data and instructions Firmware A PROM (programmable read-only memory) chip is a blank ROM chip that can be written to permanently EEPROM can be erased 27  Memory Access time is the amount of time it takes the processor to read from memory – Measured in nanoseconds 28 Memory 29  Thank YOu Discovering Computers 2010: Living in a Digital 30 World Chapter 6  HCI Lecture 07 1  The System Unit The system unit is a case that contains electronic components of the computer used to process data 2  The System Unit The inside of the system unit on a desktop personal computer includes: Drive bay(s) Power supply Sound card Video card Processor Memory 3  The System Unit The motherboard is the main circuit board of the system unit – A computer chip contains integrated circuits 4  Processor The processor, also called the central processing unit (CPU), interprets and carries out the basic instructions that operate a computer – Contain a control unit and an arithmetic logic unit (ALU) Multi-core Dual-core Quad-core processor processor processor 5 Processor 6  Processor The control unit is the component of the processor that directs and coordinates most of the operations in the computer The arithmetic logic unit (ALU) performs arithmetic, comparison, and other operations 7  Processor For every instruction, a processor repeats a set of four basic operations, which comprise a machine cycle 8  Processor Most current personal computers support pipelining – Processor begins fetching a second instruction before it completes the machine cycle for the first instruction 9  Processor The processor contains registers, that temporarily hold data and instructions The system clock controls the timing of all computer operations The pace of the system clock is called the clock speed, and is measured in gigahertz (GHz) 10  Processor The leading manufacturers of personal computer processor chips are Intel and AMD 11  Processor A processor chip generates heat that could cause the chip to burn up Require additional cooling – Heat sinks – Liquid cooling technology 12  Processor Parallel processing uses multiple processors simultaneously to execute a single program or task – Massively parallel processing involves hundreds or thousands of processors 13  Data Representation Analog signals are continuous and vary in strength and quality Digital signals are in one of two states: on or off Most computers are digital The binary system uses two unique digits (0 and 1) Bits and bytes 14  Data Representation A computer circuit represents Eight bits grouped together as a the 0 or the 1 electronically by unit are called a byte. A byte the presence or absence of an represents a single character in electrical charge the computer 15  Data Representation ASCII (American Standard Code for Information Interchange) is the most widely used coding scheme to represent data 16 Data Representation 17 Thank You 18 HCI LECTURE 08 1  INTRODUCTION In the previous two chapters we have looked at the human and the computer respectively. We are interested in how the human user uses the computer as a tool to perform, simplify or support a task. There are a number of ways in which the user can communicate with the system. At one extreme is batch input, in which the user provides all the information to the computer at once and leaves the machine to perform the task 2  INTRODUCTION At the other extreme are highly interactive input devices and paradigms, such as direct manipulation and the applications of virtual reality. Here the user is constantly providing instruction and receiving feedback. These are the types of interactive system we are considering. 3  MODELS OF INTERACTION Interaction involves at least two participants: the user and the system. Both are complex, as we have seen, and are very different from each other in the way that they communicate and view the domain and the task. The interface must therefore effectively translate between them to allow the interaction to be successful. The use of models of interaction can help us to understand exactly what is going on in the interaction and identify the likely root of difficulties. They also provide us with a framework to compare different interaction styles and to consider interaction problems. 4  MODELS OF INTERACTION We begin by considering the most powerful model of interaction, Norman’s execution– evaluation cycle; then we look at another model which extends the ideas of Norman’s cycle. Both of these models describe the interaction in terms of the goals and actions of the user. 5  The Terms of Interaction Traditionally, the purpose of an interactive system is to aid a user in accomplishing goals from some application domain. A domain defines an area of expertise and knowledge in some real-world activity. Some examples of domains are graphic design, authoring and process control in a factory. 6  The Terms of Interaction Tasks are operations to manipulate the concepts of a domain. A goal is the desired output from a performed task. An intention is a specific action required to meet the goal. 7  The execution–evaluation cycle Norman’s model of interaction is perhaps the most powerful in Human–Computer Interaction, possibly because of its closeness to our intuitive understanding of the interaction between human user and computer. The user formulates a plan of action, which is then executed at the computer interface. 8  The execution–evaluation cycle The interactive cycle can be divided into two major phases: execution and evaluation. These can then be subdivided into further stages, seven in all. The stages in Norman’s model of interaction are as follows: 9 The execution–evaluation cycle 1. Establishing the goal. 2. Forming the intention. 3. Specifying the action sequence. 4. Executing the action. 5. Perceiving the system state. 6. Interpreting the system state. 7. Evaluating the system state with respect to the goals and intentions. 10  The execution–evaluation cycle Each stage is, of course, an activity of the user. First the user forms a goal. This is the user’s idea of what needs to be done. Therefore needs to be translated into the more specific intention. 11  The execution–evaluation cycle The user perceives the new state of the system, after execution of the action sequence, and interprets it in terms of his expectations. If the system state reflects the user’s goal then the computer has done what he wanted and the interaction has been successful; otherwise the user must formulate a new goal and repeat the cycle. 12  The execution–evaluation cycle Turning on the Light 1. Establish the goal – Increase light in the room 2. Form the intention – To turn on the lamp 3. Specify the action sequence – Walk to the lamp, reach for the knob, twist the knob 4. Execute the action sequence – [walk, reach, twist] 5. Perceive the system state – [hear “click” sound, see light from lamp] 6. Interpret the system state – The knob rotated. The lamp is emitting light. The lamp seems to work 7. Evaluate the system state with respect to the goals and intentions – The lamp did indeed increase the light in the room [goal satisfied] 13  The execution–evaluation cycle Norman uses this model of interaction to demonstrate why some interfaces cause problems to their users. He describes these in terms of the gulfs of execution and the gulfs of evaluation. 14  The execution–evaluation cycle The gulf of execution is the difference between the user’s formulation of the actions to reach the goal and the actions allowed by the system. The gulf of evaluation is the difference between the physical presentation of the system state and the expectation of the user. 15 The execution–evaluation cycle 16  Human error - slips and mistakes Human errors are often classified into slips and mistakes. We can distinguish these using Norman’s gulf of execution. Slip: you have formulated the right action, but fail to execute that action correctly. Mistake: if you don’t know the system well you may not even formulate the right goal. 17  Human error - slips and mistakes Slip example: – If you understand a system well you may know exactly what to do to satisfy your goals and you have formulated the correct action. – However, perhaps you mistype or you accidentally press the mouse button at the wrong time. Mistake example: – you may think that the magnifying glass icon is the ‘find’ function, but in fact it is to magnify the text. 18  Human error - slips and mistakes slip understand system and goal correct formulation of action incorrect action mistake may not even have right goal! Fixing things? slip – better interface design mistake – better understanding of system 19 Thank You 20