Reducing the Learning Overhead A Holistic Approach to User Interface Design A modern DP equipped vessel is reliant on its position reference sensors to enable the advanced functionality that computer control brings. Each of these, and indeed many of the other vessel systems have a user interface, without which the equipment is impossible to operate. Traditional vessel interfaces were generally dedicated to the display of a single item - an analogue gauge reported the pressure in the boiler, a magnetic needle indicated north (Figures 1 and 2). Figure 1: Boiler Gauges Figure 2: Magnetic Compass Possibly the most complex task - determining the position of the vessel - used a clock and a sextant, a simple device for measuring angles (Figure 3). In living memory, vessels have gone from this traditional user interface, where the main controls were a voice pipe and a telegraph, to being packed full of modern, computer controlled systems (Figure 4). Figure 3: Fixing position with a Sextant Figure 4: A Modern bridge
Modern control systems increasingly use a computer monitor to display the user interface. This presents an opportunity to integrate functionality, and integrate systems more tightly than previously. It also brings a risk that similar systems are now controlled in different ways, leading to user confusion. Analogue gauges can be read by pattern recognition, especially when multiple variables need to be monitored to not very precise values. Figure 5: An Engine Room Control Panel Once familiar with a system then monitoring of that system becomes an unconscious act - the Chief Engineer knowing his turbines are happy (Figure 5)
Pattern Recognition: The human ability to read by pattern recognition can be illustrated with reference to the following figures: Figure 6 Showing 3:00 Figure 7: Showing 1:15 In spite of having no numerical reference most people will identify that the clocks show 3:00 (Figure 6), and 1:15 (Figure 7), and will do so in a matter of seconds.
Figure 8: Showing 7:30 Presented with Figure 8 for a short time period (e.g. 2 seconds) most people will incorrectly read the time as 4:30, when it in fact shows 7:30. Reversing the direction of the indicators breaks the stereotype of how to read a clock face. Given enough time, the correct answer can be arrived at. In a pressurised situation this confusion could lead to a serious incident. People have a range of these stereotypes, all learned through experience and interaction with systems. Similar system stereotypes include the ability to increase a controlled variable through the clockwise turning of a knob or control Volume and oven temperature controls (Figure 9) are 2 examples of this. Figure 9: A Volume Control An interesting departure from this, which causes a minor confusion similar to the left handed clock, is a fridge thermostat. To increase the effectiveness of the fridge the majority of these controls are also rotated in a clockwise direction. The dissonance comes from the result turning the fridge up decreases the temperature.
Colour: Colour is probably the most often used cross domain indicator. Red is the universal indicator for Problem, Danger. Green is used to indicate OK, No Problem, Safe. Both of these are visible on a typical traffic light (Figure 10), and in many other interactions throughout a normal user s day. Figure 10: A British Traffic Light All of these cross system stereotypes are usually deeply embedded, they are reinforced multiple times, from multiple systems. Not following cross system stereotypes in system design causes cognitive dissonance, and increases the potential for errors. One of the prototype CyScan Dashboard tilt indicators used red and green - users did not like it - "wrong use of green and red, not intuitive needs legend to understand (Figure 11) The use of Red / Amber / Green did not fit into the normal framework of Danger / Caution / Safe, and thus was rejected. Figure 11: Proposed CyScan tilt control legend
Existing System Stereotypes: In replacing the CyScan Console User interface amongst the items considered were the existing system stereotypes. The old Console has a set of numbers indicating the range and bearing to the tracked target. These numbers are also present in the new dashboard (Figures 12 and 13) Figure 12: CyScan Console Figure 13: CyScan Dashboard The visual mimic of the vessel in a circle of sea, with a representation of the tracked target on it, is also included. Incorporating these existing system stereotypes increases the initial familiarity with the new system, allowing users to adapt more easily than could have otherwise been the case.
Colour as a strong visual message has been mentioned. The numbers on the user interface are colour coded. When the system is performing well then they are green, falling through yellow to red as the system encounters a problem. This allows the user to very quickly determine the systems status, without having to consciously read any information. In the latest version of the Dashboard interface this has been improved upon. The Coordinates mode includes a display with Big Friendly Numbers. The majority of the screen is dedicated to providing large visual cues to a user, who is generally monitoring several systems, in a similar manner to the array of analogue gauges illustrated earlier. (Figures 14, 15 and 16) Figure 14: Coordinates Mode - 100% quality Figure 15: Coordinates Mode - 60% Quality Figure 16: Coordinates Mode - 10% Quality Figure 17: Coordinates Mode - Targets Lost When the system needs attention then the Big Friendly Numbers drop back to the Birds Eye View (Figure 17) the appearance of a big blue circle being the visual equivalent of a klaxon.
Figure 18: A typical small car Any new system requires a user to become trained in its use. When learning how to drive a car (Figure 18) a user is presented with a complex user interface that includes a direction controller (steering wheel), a velocity controller (accelerator / brake pedals), peripheral systems to allow external users to be informed of changes in velocity or direction (brake lights and indicators), systems to assure vision in the case of precipitation (windscreen wipers), and many other functions. The majority of these systems are quite standardised, but the placement of the controls can vary. The result is that when using a different version of the interface, such as a hire car, users may indicate with the windscreen wipers. In general this does not cause any issues, other than embarrassment. However the potential for an incident is clearly increased by this change to the user s familiar interface. When new versions of office software are released there is often a need to retrain, leading to a dip in productivity as users adapt to the new placement of functions, and new improved methods of working. Either of these scenarios is relatively low risk, but illustrates that changes in existing user interfaces should be carefully thought out before new versions are released.
Guidance Approach: Guidance Marine manufactures 4 referential positioning sensors: CyScan, RadaScan, MiniRadaScan and Artemis (Figures 19, 20, 21, and 22). Figure 19: CyScan Mk4 Figure 20: RadaScan Figure 21: MiniRadaScan Figure 22: Artemis Mk5 Each of these sensors have different operational characteristics, but all of them need a User Interface to function.
Common, Similar, Different: Reducing the user interface to Common, Similar, and Different elements enables a reduction in the learning that is required for each system. Elements which may not appear to be common, such as the Targets used by RadaScan and CyScan, can be further broken down. The RadaScan Targets give a unique key, which the sensor can lock onto. The CyScan targets are simple retro reflective items. The commonality is that both have range, bearing and a quality indication. The additional RadaScan information can be simply incorporated into a targets list that has the common elements plus the special RadaScan elements. (Figures 23 and 24) Figure 23: CyScan Dashboard Targets list Figure 24: RadaScan Dashboard Targets list Artemis is similar to RadaScan, in that it has a uniquely coded target. The system can only ever have 1 target, so the CyScan / RadaScan targets list is not required. Artemis has a long history, and its user base already knows how to use the previous user interface. In moving to the Dashboard elements of that user interface need to be retained, whilst also fitting with the holistic Guidance Marine Dashboard approach. The historic Artemis user interface has a mode where the main screen is dedicated to show status numbers. The Dashboard has incorporated a version of this in the new Coordinates mode view, whilst still maintaining the elements of the CyScan and RadaScan dashboard. This familiar view helps to ease the transition between user interfaces.
The Common, Similar, Different approach aids training. By ensuring that tasks are performed in a similar manner there is more unconscious reinforcement across all systems, leading to a greater likelihood that the instinctive reaction will be the correct one. The Alarms list in CyScan, RadaScan, and Artemis all present information in the same manner, and have the same user interactions. (Figures 25, 26, and 27) Figure 25: Artemis Dashboard Alarms list Figure 26: CyScan Dashboard Alarms list Figure 27: RadaScan Dashboard Alarms list
The Dashboard sidebar illustrates the similar principle. The systems have similar outputs (Range and Bearing to target) and individual controls for the differing operational abilities Artemis, for instance, has the ability to steer the antenna direction, whereas CyScan and RadaScan continuously rotate. (Figures 28, 29 and 30) Figure 28: Artemis Dashboard sidebar controls Figure 29: RadaScan Dashboard sidebar controls Figure 30: CyScan Dashboard sidebar controls
Conclusion It is clear that embedded stereotypes affect users interactions with systems. By considering these stereotypes in a holistic manner during the design phase many of them can be used to provide an interface that is immediately comfortable to the user. This aids the training process, and ensures that the user interface does not unnecessarily place cognitive load on the user, allowing a more efficient, safer, familiar end user experience. If multiple similar systems are to be deployed then thought given to finding the commonalities can be repaid in improved efficiencies and reduced training needs. Guidance Marine is committed to providing the marine industry with the widest range of holistically managed position reference sensors available, and is keen to receive feedback from end users to make their jobs easier, safer, and more enjoyable.
References Images used in this document sourced from: Figure 1: Boiler Gauges Hunslet Engine Co, photograph, viewed 19 Aug 2015, http://goo.gl/xqjcfr Figure 2: Magnetic Compass Sestrel Circum deadbeat ships compass Liveauctioneers.com, photograph, viewed 19 Aug 2015 https://www.liveauctioneers.com/item/7186599_sestrel-circum-deadbeat-ships-compass Figure 3: Fixing position with a Sextant Wikimedia commons, photograph, viewed 19 Aug 2015 https://goo.gl/z3xvhy Figure 4: A Modern bridge Sam electronics, photograph, viewed 19 Aug 2015 http://www.sam-electronics.de Figure 5: An Engine Room Control Panel Fabrizio Di Fraia, 2003, Engine room propulsion control room, photograph, viewed 19 Aug 2015 http://www.simplonpc.co.uk/transvaalcastlepc4s.html Figure 9: A Volume Control Freegreatpictures.com, 2011, photograph, viewed 19 Aug 2015 http://www.freegreatpicture.com/stage-venue/volume-control-knob-50147 Figure 10: A British Traffic Light Unisouth commonswiki, 2008, A LED traffic light in Portsmouth, England, photograph, viewed 19 Aug 2015 https://en.wikipedia.org/wiki/traffic_light#/media/file:modern_british_led_traffic_light.jpg Figure 18: A typical small car Aero777, 2014, Proton Iriz, photograph, viewed 19 Aug 2015 https://en.wikipedia.org/wiki/proton_(automobile)#/media/file:2014_proton_iriz_1.6l_premi um_in_shah_alam,_malaysia_(01).jpg