ITU-T Z 361-1999 Design Guidelines for Human-Computer Interfaces (HCI) for the Management of Telecommunications Networks - Series Z Languages and General Software Aspects for Telecpec.pdf

1、INTERNATIONAL TELECOMMUNICATION UNION ITU=T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU 2.361 (02/99) SERIES Z: LANGUAGES AND GENERAL SOFTWARE ASPECTS FOR TELECOMMUNICATION SYSTEMS Man-machine language - Specification of the man- machine interface Des i g n g u i del i nes for H uma n -Com pu te

2、r Interfaces (HCI) for the management of telecommunications networks ITU-T Recommendation 2.361 (Previously CCITT Recommendation) STD-ITU-T RECMN Z.3bL-ENGL L777 m 4862571 0b59b03 2b8 - ITU-T Z-SERIES RECOMMENDATIONS LANGUAGES AND GENERAL SOFTWARE ASPECTS FOR TELECOMMUNICATION SYSTEMS FORMAL DESCRIP

3、TION TECHNIQUES (FDT) Specification and Description Language (SDL) Application of Formal Description Techniques Message Sequence Chart CHILL: lhe ITU-T high level language General principles Basic syntax and dialogue procedures Extended MML for visual display terminals PROGRAMMING LANGUAGES MAN-MACH

4、 I NE LANGUAGE 2. I 00-2. 1 o9 z.110-2.119 Z. 120-2.129 2.200-2.209 2.300-2.309 2.310-2.319 2. 320-2.329 11 Specification of the man-machine interface 2.3304.399 QUALITY OF TELECOMMUNICATION SOFTWARE METHODS FOR VALIDATION AND TESTING 2.400-2.499 2.500-2.599 For further details, please refir to ITU-

5、T List of Recommendations. STD-ITU-T RECMN Z-3bl-ENGL 1999 48b2591 0b59b04 LT4 W ITU-T RECOMMENDATION 2.361 DESIGN GUIDELINES FOR HUMAN-COMPUTER INTERFACES (HCI) FOR THE MANAGEMENT OF TELECOMMUNICATIONS NETWORKS Summary The design of network management user interfaces is critical for the successful

6、operation of telecommunications networks. This Recommendation provides a set of guidelines for the design of Human-Computer Interfaces (HCI) for the management of telecommunications networks. The general body of human factors knowledge and practice is important to these designs. In addition, telecom

7、munications network management user interfaces can benefit from the application of the additional design guidelines in this Recommendation. Annex A contains a number of important generic design principles selected from the HCI literature. Appendix I contains additional reference material. Appendix I

8、I contains a technical framework which relates these guidelines to the HCI reference model provided in Recommendation 2.352 Source ITU-T Recommendation 2.361 was prepared by ITU-T Study Group 10 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 12th of February 1999. Keyw

9、ords Design guidelines, Human-Computer Interface (HCI), Network Management, OAM less likely to produce errors; more efficient in accomplishing goals; o o b o more pleasing to use. Telecommunications network management applications have specific characteristics which should be addressed when designin

10、g the user interface. Collectively, the following aspects differentiate these applications. Telecommunications network management HMls can be time critical - In the management of a telecommunications network, and specifically the fault management application, faults may be critical and demand attent

11、ion immediately. Thus the notions of asynchronous interrupts and the need to access specific information coupled with specific actions are vital for the user. of large telecommunications networks carrying large volumes of traffic demands a rigorous approach to the means of ensuring that problems or

12、troubles do not go undetected. likened to traffic control centres where large numbers of apparently isolated events may occur. Providing the user with assistance in prioritizing, filtering and managing these inputs is essential in the design of effective network control applications. application, a

13、user is confronted with files, documents, and possibly spreadsheets. A typical network control application deals with complex central office switches, optical and other broadband transport equipment, facilities both owned and leased, plus a host of other equipment types each of which has different c

14、apabilities and requirements. o Errors can cause great damage to the network - The potential to disrupt significant sections o Users handle Zarge volumes of dutu, often in real time - Network control centres can be b Telecommunicafions networks are often large complex systems - In a typical office R

15、ecommendation 2.361 (02199) V STDaITU-T RECMN 2-3bL-ENGL I999 4862571 Ob59609 78b Recommendation 2.361 DESIGN GUIDELINES FOR HUMAN-COMPUTER INTERFACES (HCI) FOR THE MANAGEMENT OF TELECOMMUNICATIONS NETWORKS (Geneva, 1999) 1 Scope This Recommendation provides guidelines for the design of the G interf

16、ace of a Telecommunications Management Network (TMN). The G interface is the human-to-workstation interface of a TMN. The reference model for a TMN is defined in Recommendation M.3010. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference i

17、n this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most re

18、cent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. - ITU-T Recommendation M.30 1 O (1996), Principles for a telecommunications management network. ITU-T Recommendation M.3 1 O0 (1999, Generic network info

19、rmation model. CCITT Recommendations 2.301-2.341 (1988), Man-Machine Language (MML). specqcation technique - Introduction. specjcation technique - Scope, approach and reference model. - - - ITU-T Recommendation 2.35 1 (1 993), Data oriented human-machine interface - ITU-T Recommendation 2.352 (1 993

20、), Data oriented human-machine interface 3 Terms and definitions This Recommendation defines the following terms: 3.1 Human-Computer Interface (HCI): The HCI is an implementation of the G reference point of the TMN. 3.2 Human-Machine Interface (HMI): HMI is the term used in several Z-series Recommen

21、dations and refers to the same interface as the newer term, HCI. 3.3 series of Recommendations. I Telecommunications Management Network (TMN): A TMN is specified by the M.3000 Recommendation 2.361 (02/99) 1 4 Abbreviations and acronyms This Recommendation uses the following abbreviations: HCI Human-

22、Computer Interface HMI Human-Machine Interface OAM b) c) detect important signals or changes in the objects; understand the context of the current displayed objects, 6.1.3 Rationale Graphic displays should communicate their current state to the user clearly, unambiguously and directly. Users should

23、be able to detect ail relevant information, should not misplace or lose important information or functions, and should not lose their way around the interface. This is especially true when network problems or emergencies occw. There are two basic contributors to human ability to detect signals in an

24、y environment: the strength and quality of the signal, and the noise or irrelevant data in which signals are always embedded. Noise impacts all perceptual dimensions and can affect signal interpretation. 2 Recommendation 2.361 (02199) The effort required to work in noisy environments also has negati

25、ve physical and emotional effects. For example, displays with many and/or bright colours and containing too much unnecessary information will cause visual fatigue, irritations of the eyes, muscle tension, and may lead to chronic headache and other stress-related complaints. Examples of design implic

26、ations In general, there should be no more than three levels of information within a given display: 1) Background (the level containing the frame of reference or context, e.g. geographical maps or schematic diagrams); 2) Middleground (the level which contains the objects of interest to the user, e.g

27、. nodes in the network); 3) Foreground (the level which contains the most important signals to the user, e.g. display elements used to differentiate alarmed objects in the network). These levels should be differentiated in terms of brightness and/or saturation variations, with the highest brightness

28、 and/or saturation given to the foreground. Displays should limit the number of colours that are presented simultaneously in the foreground. As a rule of thumb, four different hues could be displayed simultaneously without overloading the display. Use simple graphical shapes. Avoid overuse of highli

29、ghts and excessive detail. Simplify complex networks through the use of containers for presentation when large numbers of nodes are involved. Containers are objects which hold instances of other objects. 6.1.5 Graphic examples Figure 6.1-1 is an example of a noisy display. The designer has chosen to

30、 show all possible nodes and links. Different shapes are used to designate some characteristic of the nodes, and saturated colours and strong backgrounds are present. Detecting new alarm information is critical to some tasks and is not made easier by the excess information in this display. T1010880-

31、98 Figure 6.1-UZ.361- A cluttered display Recommendation 2.361 (02/99) 3 STD-ITU-T RECMN 2.3bI-ENGL 1999 b 4862591 0659632 270 m The example in Figure 6.1-2 demonstrates a minimal background, with a limited set of major nodes displayed for reference. The ability of the user to detect changes or impo

32、rtant signais is greatly enhanced. The presence of the alarm (C2) is clearly apparent to the user. Ti01 0890-98 Figure 6.1-2/2.361- Example of minimized information 6.2 Maintaining appropriate context 6.2.1 Background various views of the physical or logical network. Windows are often opened in orde

33、r to enable the user to accomplish specific tasks, for example to manipulate the state of a particular piece of network equipment. Some designs do not adequately link the subsequent window or task manager screen to the previous operational context. As the tasks may be complex or involve a number of

34、screens, it becomes increasingly difficult for users to remember the original context. Users need to be able to maintain the relevant context fiom which applications are accessed, worked on and eventually closed. I Network management user interfaces generally deal with tasks such as surveillance by

35、presenting 6.2.2 Design guideline The context from which specific task managers or applications are launched should be kept visible and accessible until the task is completed or the application closed. 6.2.3 Rationale Interfaces have been designed in which the user is obliged to open a large number

36、of windows in order to complete a task. These windows may mask or cover up the high-level context of the application, thus preventing the user from being able to see or recover the original network map or view. Complex tasks requiring problem-solving should be facilitated by keeping visible the rela

37、tionship between the application and the relevant context. 4 Recommendation 2.361 (02199) STDmITU-T RECMN Z.363-ENGL L999 I862571 Oh57613 LO7 = Examples of design implications The default window size and placement should be set so that, when opened, it does not completely cover the previous view. Th

38、e application to which windows belong should be shown in the window headers. Critical information such as alarm banners should never be covered by the application dialogue windows. Screen pictures or windows should contain information that clearly indicates the source from which they were generated

39、or derived. Graphic example In Figure 6.2-1, the detailed view and the overall topographical map both indicate the same network region and the fact that there is an alarm present. The user can easily recognize what region the affected element belongs to. This is an example of geographic context. Fig

40、ure 6.2-UZ.361- Maintenance of context 6.3 Providing redundant coding in all important graphic displays 6.3.1 Background Network management applications are often required to present information to users which requires them to take action. In fault management, for example, alarms may require immedia

41、te action if network degradation or failure is to be avoided. This guideline is a more general case of the guideline in 2.1.3/2.323 item a), which points out that colour should not be used as the only visual coding mechanism. 6.3.2 Design guideline When presenting time-critical or important informat

42、ion about HCI objects, a minimum of two visual cue dimensions (e.g. shape, size, colour, position, etc.) should be varied simultaneously. Such time- critical information should be presented in the foreground as defined in guideline 6.1. Recommendation 2.361 (02/99) 5 6.3.3 Rationale A given network

43、element may have any number of active alarms, some of them acknowledged, others not. In addition, the network element may be in one or more states. Communicating this complexity to the user by varying only one dimension will result in complex and extensive coding schemes which will be very difficult

44、 to interpret and remember. It is easier to tell one object from another if their colours, shapes, or other attributes are different than if they were identical in all but one of these dimensions. This multidimensional perceptual presentation allows people to overcome physical limitations such as co

45、lour blindness, and environmental adversities such as poor lighting. 6.3.4 Examples of design implications d Colour should not be used on its own as a mechanism to communicate important or time- critical changes of state. Colour can enhance the effectiveness and attractiveness of carefully-designed

46、displays. However, note the following: 1) A significant proportion of the population is partially colour-blind. Of this population, the largest proportion has difficulty in discriminating between red and green. 2) Colour displays are notoriously difficult to control and calibrate properly. Improper

47、settings not only cause stress and physical discomfort, but can also mask information that is coded in colour. 3) Displays should effectively convey important information to the user even if the display mechanism is degraded. It is desirable that one of the dimensions included in the coding mechanis

48、m for display of object state be textual. Text information, used intelligently in conjunction with other graphic displays, can enhance the effectiveness of the display by providing an explicit verbal label of the state for the user. This will help users communicate among themselves, and will facilit

49、ate access to support documentation. b) 6.3.5 Graphic example The example in Figure 6.3-1 shows the situation when an alarm has been raised against a particular node. Redundant coding is realized by changing the nodes shape, adding some critical information and by changing the colour of the node. T1 O1 0910-98 Figure 6.3-UZ.361- Redundant coding 6 Recommendation 2.361 (02/99) STD-ITU-T RECMN Zm3bL-ENGL 1393 m 4db2591 Ob59b15 TT 6.4 Flattening the hierarchy 6.4.1 Background Most people have problems when traversing hierarchical user interface systems because they often lose their