Please expalin each of the terms breifly. and answer each of the bullet point De
ID: 3592863 • Letter: P
Question
Please expalin each of the terms breifly. and answer each of the bullet point
Designing and Specifying the System
Interface design
1. Conceptual model vs mental model vs user model
2. Cognitive ergonomics
3. Working from a task analysis
4. Style of dialog: command line, menus/icons/forms, direct manipulation
5. Evaluating the design: heuristic eval./mockups or prototypes. User testing with observation
Documenting the choices in the functional speicification: what is meant to different audiences.
Explanation / Answer
2)Answer:
Cognitive ergonomics, defined by the International Ergonomics Association "is concerned with mental processes, such as perception, memory, reasoning, and motor response, as they affect interactions among humans and other elements of a system. The relevant topics include mental workload, decision-making, skilled performance, human-computer interaction, human reliability, work stress and training as these may relate to human-system design." Cognitive ergonomics studies cognition in work and operational settings, in order to optimize human well-being and system performanc.
Ergonomics is sometimes described as "fitting the system to the human," meaning that through informed decisions; equipment, tools, environments and tasks can be selected and designed to fit unique human abilities and limitations. Typical examples in the "physical ergonomics" arena include designing a lifting job to occur at or near waist height, selecting a tool shape that reduces awkward postures, and reducing unnecessary tasks and movements to increase production or reduce errors and waste. "Cognitive ergonomics," on the other hand, focuses on the fit between human cognitive abilities and limitations and the machine, task, environment, etc. Example cognitive ergonomics applications include designing a software interface to be "easy to use," designing a sign so that the majority of people will understand and act in the intended manner, designing an airplane cockpit or nuclear power plant control system so that the operators will not make catastrophic errors.
Cognitive ergonomics is especially important in the design of complex, high-tech, or automated systems. A poorly designed cellular phone user-interface may not cause an accident, but it may well cause great frustration on the part of the consumer and result in a marketplace driven business failure. A poor interface design on industrial automated equipment, though, may result in decreased production and quality, or even a life threatening accident.
Complex automated systems create interesting design challenges, and research and post accident analysis indicate that the human role in automated systems must be closely considered. Automation can result in increased operator monitoring and vigilance requirements, complex decision-making requirements, and other issues that can increase the likelihood of errors and accidents.
3)answer:
task analysis:
Task analysis is a business methodology of analyzing employee tasks to improve the way core business processes are being run within a company, helping organizations to become more efficient.
->Task Analysis enables the effective management of employee's tasks using accurate working time recording, monitoring and analysis.
->Only through analysis of the data that you can begin to understand employee behavior, identify working trends and discover where work can be made more efficient.
->Together these enable to accurately model and predict future employee behavior and lay a foundation for improving business performance.
Task Analysis Lifecycle
Task analysis activities are grouped into five categories: time recording, prioritization, monitoring, analysis and optimization:
Time Recording is where the actual time for each of the activities is recorded.
Time can be recorded by the employees themselves or by automatic time data collection.
Precise account of working time according to definable rules, recorded in real-time.
Prioritization is where the strategic decisions are carried out.
Priorities are refined based on importance and urgency.
Employee resource planning and task scheduling is set across all employee activities.
Monitoring measures task-related performance using key performance indicators to monitor how the strategy is performing.
Monitoring uses three main parameters; Time, Priority and Cost.
Understanding where the inefficiencies in the process are key for future improvement.
Analysis is the most critical to lifecycle success.
The aim of this stage is to analyze the records gathered through monitoring and to compare them with an a priori time plan.
Analysis enables to detect discrepancies between the time plan execution and the a priori model, as well as to analyze bottlenecks.
Optimization is where strategic decisions and priorities are refined based on the the analysis.
Employee resource planning and task scheduling is revised and integrated across all employee activities
4)Answer:
Command languages:
In a command language, the user must type in a complete command (command name plus arguments) without any prompt other than a general one indicating readiness. There may or may not be a response: often silence and another general prompt is all the indication there is of success (or failure). It is not like natural language, where within wide limits anything may be said, but rather like commands over a voice pipe in a ship: though the units are "words", they are chosen from a special vocabulary. Thus in fact only a limited number of commands are allowed; it is just that the system does not give the user any information about them in advance. To get information, the user must ask for it explicitly. On the other hand, there is no delay while information is printed by the system and then read by the user: users can issue commands as fast as they can type. It is typical of such systems that they use short command names to maximise this speed. The command names in this style of editor are frequently a single letter, despite the problems this can lead to in remembering their meaning. Thus in general, command language styles maximise speed (usability for experts) at the expense of learning burden. They are often chosen because the display is small and slow relative to the size of the command set.
Menus
A common alternative is menu systems, where the finite possible set of commands is displayed in some way, and the user issues a command by reference to such a display. In fact, there is almost never enough screen space to display all the commands at once. For instance in the Mac system the permanent display has only a single horizontal menu called the menubar, and the user must click on one of its items to see more choices. If you look at the width of the menu displayed, you will see that it is wider than its title, and that therefore you could not display all of the menus at once. Thus the user must still perform some action to get the information they need. Indeed in some menu systems, called popup menus, NO information is displayed until requested (e.g. Sun windows, or the Smalltalk language). This minimises the cost in space, but the user must have learned what to do to get the display, and must take the time to perform that action, and wait for the display to be drawn. On small machines this can be annoying, and even on fast machines there are frequently keyboard alternatives, implying that at least some users find it is worth the extra learning to save the execution time. Note that it is not only the display time: to issue a menu command users must position the mouse pointer, and that takes time because they must look at the screen while aiming the pointer.
Menus do not have to be vertical lists of words. For instance the Tools menu in Hypercard is a pulldown menu of icons (pictures), arranged in a grid, and in many drawing programs there is a permanently displayed "palette" of icons representing operations. Tearoff menus combine these ideas: they are opened like pulldown menus, but can be "torn off" and left permanently open like a palette. Menus can combine text and pictures (icons and words). Popup menus are not only not permanently visible like palettes, their superior menu is not permanently visible, (i.e. unlike the "menubar" for pulldown menus). Note that which menu pops up may depend both on which button you press, and on where you click. Menus can also be round "pie menus".
Icons:
•Small picture or image
•Represents some object in the interface often a window or action
•Windows can be closed down (iconifed)
–small representation Þ many accessible windows
•Icons can be many and various highly stylized or realistic representations
Direct Manipulation Interface Examples:
•Display editors and word processors
•Spreadsheet programs
•Spatial and geographic databases
•Video games and educational simulations
•CAD and paint type applications
•Hypertext
•Office automation software
•Virtual reality
Principles of Direct Manipulation :
• Pointer as your virtual hand
• Mouse as your control into said world •
2-dimensional (for the most part)
• Intuitive, natural
• Direct manipulation perfect analogue
Strengths of Direct Manipulation :
• Natural analogue to how we interact with the real world
– Ease in learning the system originally and in assimilating advanced features
– Confidence in the capacity to retain mastery over time
– Enjoyment in using the system
– Desire to explore more powerful aspects of the system