Communication & Display Design

1. Communication & Display Design doyoyekti@yahoo.com

2. Introduction • Human activites and task involve some form of communication, in which information is exchanced between one and more partisipants. • People communicate with each other by talking, writing and various forms of non-verbal communication.

3. Man-Machine • People’s interactions with machines, tools, computers, consumer products, and other devices they use to perform tasks can also be viewed as a form of communication • People tell machines or other devices what to do, using controls and input devices, and are told what to do and what not to do by displays, signs, signals, and other information-bearing cues in their environment.

4. A communication system, as originally proposed b Shannon (1948), consists of : • An information source that produces the message(s) to be communicated • A transmitter that converts or codes the message into a signal suitable for transmission • A channel that transmits the signal from transmitter to receiver • A noise source that adds noise to channel • A receiver that reconstructs or decodes the message from the signal

5. An Abstract Communication System Source of Signal Destination of Signal Encoder & Signal Decoder & Receiver Channel Internal noise External Noise These components of a communication system are generic in nature and can be used to distinguish a wide variety of communication scenarios (Lehto & Miller, 1986)

6. Information Transmition • The succesfully communicate a message, the message must first be sent. • For example, a speedometer might display the current speed of vehicle. The intended receiver must then notice, understand and respon appropriately after receiving the message.

7. KLM Flight 4805, Boeing 747-206B, PH-BUF, ground collision with Pan American Flight 1736, Boeing 747-121, N735PA • Location: Tenerife, Canary Islands (Spain) • Date: March 27, 1977 • Both aircraft - KLM Flight 4805, a Boeing 747-206B, Reg. No. PH-BUF; and Pan American (Pan Am) Flight 1736, a Boeing 747-121, Reg. No. N736PA, - had been diverted to Los Rodeos Airport on the Spanish island of Tenerife in the Canary Islands due to a bombing at the airport at their final destination, the neighboring island of Gran Canaria. • Later, when flights to Gran Canaria resumed, the aircraft collided on the runway in Tenerife as the KLM Boeing 747 initiated a takeoff while the Pan Am aircraft was using the runway to taxi.

8. The Spanish investigative authority, Subsecretaria de Aviacion Civil, found that the fundamental cause of the accident was the KLM captain: 1. Took off without clearance; 2. Did not obey the "stand by for take off" direction from the tower; 3. Did not interrupt take off on learning that the Pan Am aircraft was still on the runway; and 4. In reply to the KLM flight engineer's query as to whether the Pan Am aircraft had already left the runway, the KLM captain replied emphatically in the affirmative. • The investigation also believed that the KLM captain's decision to take off may have been influenced by revised crew duty time limitations recently enacted by the Dutch government. The restrictions were inflexible and highly penalizing to the captain, if exceeded. • With a total of 583 fatalities, the crash remains the deadliest accident in aviation history. All 248 passengers and crew aboard the KLM flight were killed. There were also 335 fatalities and 61 survivors on the Pan Am flight.

9. Man/People Environment Lack of communication sleppiness fatique, Bad mood Wrong intepretation Wrong decision Incident Lack of knowledge Wrong sense Lack of skill virus software Communication is not standardized Mechanical failure Hardware SOP wrong Method Machine

10. Communication Capability / Limitation Capability / Limitation Man People INFORMATION Noise INFORMATION INFORMATION Machine Tools Computer Product

11. Human Information Processing Model (Wickens, 1984)

13. How to Calculate Information (coin toss) H = Log2n 50% 50% H : Amount of Information (bit) n : The number of equally likely alternatives H = Log2 2 = 1 bit n=2 H = ∑pi * Log2(1/pi) 90% 10% Pi : Probability of ith event i : Alternatives from 1 to n H = 0,9*Log2(1/0,9) + 0,1*Log2(1/0,1) = 0,9*0,152 + 0,1*3,32 = 0,469 bit

14. LatihanSoal 100% 0% H = 1*Log2(1/1) + 0*Log2(1/0) = 0 + 0 = 0 Information ≈ Unexpected Event

15. Human Capability • Vary among Human • Sensory storage of ear : 10.000 bits/sec (not including decision making process) • Maximum information processing vary 6 – 50 bits/second • (Freivalds, 2009)

16. Memorize in 10 second 1293458 234598456123

17. 1. Chunking 2. Rehearsal 3. Association

18. Selective Attention • A general finding of early reseach on human information processing was that people are limited in their ability to transmit information. • People have a tendency to see or hear what they expect to see or hear

19. The Role of Working Memory • When people perform tasks, they are constantly shuffling information in and out of consciousness • This process is nicely described by production system model of human cognition (Newel & Simon, 1972; Anderson, 1983) • Task performance is described in terms of the changing contents of working memory in which has a limited capacity of 5 to 9 items • The content of working memory changes over time when new information entering working memory replaces or over writes the existing contents • The new information can enter working memory when information from the environment is perceived or when fact are retrieved from long-term memory

20. Well integrated sources of information can act as cues that trigger the retrieval of additional, and hopefully relevant, information from long term memory Providing information only at the time it is relevant also reduces the chance of overloading working memory and minimizes the change of distracting the operator

21. Example : • Lockout tag is placed next to an activated lockout • Switched are labeled on control panel • Sign placed on a door warns against entering

22. The Mode of Processing • There are two modes of cognitive processing • One is automatic, less capacity-limited, Possibly parallel, Invoked directly by stimulus input • The second requires conscious control, has severe capacity limitations, is possibly serial and is invoked in response to internal goals

23. Decision Making • The ultimate objective of the communication process is to improve decision making of real people in real environments

24. DISPLAY DESIGN • Displays are devices designed to communicate messages to people/machine/tools Classical view of the human-machine interface (Chapanis, 1965)

25. In most cases, display perform a supportive role, in which they supplement other sources of information that might be available to the person using the particular device

26. Types of display • Visual display ; are the most encountered • Static display (ex : sign, label, book) • Dinamic display (ex : speedometer, fuel gauges, oil pressure, temperatur indicator) • Analogue & Digital display • Warning or alerting display • Predictive or historical display • Instructional, command or advisory display • Spatial display (diagram, figuren & chart) • Symbolic display • Pictorial display (images) • Auditory display; tend to used for alerting or warning related purposes (Wide array of sirens, horns, bells, tones, beeps or buzzers)

27. Principle of Display Design (1) • Sensory Modality • The most appropriate sensory modality of a display depends on its intended function, sensory demands of the background of the background task, and sensory capabilities of its intended audience • Display that combine sensory modalities can be particulary effective when tasks are performed under changing condition • Display Location & Layout • Locate visual displays where they can be seen and put more important visual in more central locations • Display should provide their information at the time it needs to be used • Displays and display elements should be grouped consistently with the sequence in which they are used by the operators • Tasks requiring information integration are better served by more integrated object-like displays

28. Principle of Display Design (2) • Object that are placed close together will be more likely to be viewed as being related • Position displays or display elements so they have obvious spatial referents Legibility of Display Element • The minimum size of a critical detail should be 5 minutes of visual arc for novice observers and not less than 2 minutes of visual arc for experienced operators • Symbols and alphanumeric characters should subtend a visual angle of at least 12 minutes of arc • Display should provide an adequate contrast between visual elements and their background • Avoid crowding of display elements • Take steps to deal with the effect of degraded legibility due to aging and adverse environmental conditions

29. For rapid and accurate identification of individual characters, 16 to 18 minutes of arc is normally adequate, although reading speed continues to increase until character height exceeds 22 arc minutes (Chung et al., 1998; Giddings, 1972; Legge et al., 1985; Legge et al., 1987; Legge et al., 1990; Strasburger et al., 1991). A width-to-height ratio (“Width”/“Height” in Figure 7-4) shall be from 0.5 to 1 to 1 to 1 and, for optimal legibility and readability, should be from 0.6 to 1 to 0.9 to 1. Legibility is sometimes sacrificed to some extent for esthetics, conservation of space, or other practical considerations (Benson, L., & Farrell, 1988; Soar, 1955).

30. Principle of Display Design (3) • Information Content and Coding • Display instructions should whenever possible be stated in a positive manner • Be Selective • Let the user control the amount and detail of information presented • Information about the current or desired state or condition of system, item, • Display that mae derivative information easily available make it easier for people to predict what will happen • Be as realistic as possible in describing the variable you are trying to communicate • The direction of movement of an indicator on a display should be compatible • Color coding is a good tool for conveying relationship between display elements; • Many coding schemes other than color, including shape • Verbal and numerical codes tend tobe better understood and requires less learning than symbols or other coding methods • The use of analogies and metaphors often can greatly improve the learnability and understandability of display element • In most cases, line graph are preferred slightly over vertical bar graphs and preferred strongly over horizotal bar graphs • Multiple single line on single line are prefered over multiple single line graphs in point reading • Varioation in pitch, amplitude, an modulation can be used to specified distinguished sounds.

31. Presentasi • ANSI-HFES 100, 2007 • Kelompok 1 : bab 5 • Kelompok 2 : bab 6 • Kelompok 3 : bab 7 • Kelompok 4 : bab 8 • Kelompok 5 : bab 1,2,3,4

32. Presentasi • ANSI-HFES 100, 2007 • Kelompok 3 : bab 7 • Kelompok 4 : bab 8

33. Good and Bad Display • Contoh-contoh display (baddesign.com) • Standard (ukuran huruf, kontras, jarak pandang, dsb)