Thoughts on taking advantage of the booming computer industry to provide ship drivers with critical information without overloading the users.
Information and processing systems in the civilian industry continue to get bigger, stronger, and faster. It would be possible to replace an entire submarine’s fire control and sonar system with smaller, cheaper PC equivalents. One of the Naval Undersea Warfare Center’s main foci is on development of new submarine systems that incorporate this civilian industry and technology. This shift in focus cannot be applauded enough. In a recent statement at the Sub School Change of Command, Rear Admiral Tobin of CNET, stated the Submarine Force should be leading the computer revolution. Submariners are continually frustrated by having to operate warships in the 1990s based on 1970s and ’80s technology. In the civilian world, if manufacturers such as the automobile companies operated in this manner, they would be out of business. Similarly, operating the Submarine Force using out-of-date technology is not only less efficient, but it is more costly. Cost benefit analysis, as well as anecdotal evidence from manufacturers and supply officers, point out that the upfront cost of replacement is often high, however, the cost of continually repairing out-of-date equipment is usually higher in the long run.
As the Submarine Force moves into this technological explosion our processing power will greatly increase leading to the ability to display more and more information. Over the next few years as the successors to the Pentium· processors come out this power will only continue to grow-leading to the display of even more information.
The real question becomes how to use this power to process and display large amounts of information in the most efficient means possible, to improve the ship’s performance and enhance the ability of her crew. In the succeeding sections, an outline is presented of how quantitative, as well as qualitative, human factors engineering should be applied to the accomplishment of the above stated goals. I will be drawing not only on my naval experience, but also experiences at the University of Michigan (where I recently completed two M.S. degrees in Nuclear Engineering, and Industrial and Operations Engineering-concentrating in human factors.) At Michigan, we studied such issues as they relate to civilian nuclear power control and manufacturing system controls.
The outline will cover: 1) a brief description of Human Information Processing and Basic Information Theory; 2) Perceptual Attention Organization and Processing; and 3) Spatial Perception, Cognition, and Display of Spatial Information.
Human Information Processing: and Basic Information Theory
There are seven basic parts to the model of human information processing. They include: sensory processing, perception. working memory. long term memory, decision and response selection, response execution, and attention resources.
Each one of these categories is an entire book unto itself and would be impossible to cover in a single paper. The point of presenting this model is to establish a basic flow path for information processing. Using this model as a guide, ideas on how to measure and improve information processing by manipulating the different components of the model are explored.
The main problem with the current Navy submarine develop-mental programs is that the programs rely on feel good human factors engineering. Sailors are questioned on what they need and would like to see implemented on new systems. The designers then try to accommodate the stated needs. This is an excellent first step, for who knows what is wrong or needed in a system better than the operators? Industry often executes the exact same process leading to results which are often dramatic. However, this is where the Navy appears to stop the development process, unlike the manufacturers. Worker input should be the starting point, not an ending point. to the development process for information display systems.
Once the inputs have been received, designers need to develop display systems to take advantage of spatial perceptions and cognitions. By manipulating the displays it is possible to take advantage of common perceptions and cognitions to allow greater processing speeds. These new displays can then be mathematically tested to determine which are the most beneficial. The bottom line is that by altering the display, processing of information can be improved. These improvements can be tested mathematically vice just feeling to see which is better.
An illustration of a mathematical method for measuring information transmitted, equivocated, polluted by noise, and finally received is information theory. Given that every event on particular display has a given probability (pi) of being transmitted, the information conveyed by a stimulus (or stimuli) in bits (H) = log2 l/p1 • With this equation, it is possible to calculate the average information conveyed (HavJ by series of events with different probabilities, like a series of warning alarms. This is the source strength or transmission signal of the original information. The signal is now influenced by equivocation losses (or loss of the signal during transmission) which will degrade the received signal. The original signal also suffers corruption from noise that enters the transmission channel. All of these factors can be measured to determine which system transmits the clearest signal to the operator thereby improving the processing of information. This method of measurement also will give a quantitative measurement of the maximum amount of information a person can process for a given display system.
The main point of this section is to show that there are mathematical methods that quantitatively analyze human factors information. The mathematical analysis needs to be integrated into the initial development of new systems. This quantitative data can be used to compare different display systems and offer directions in which these systems can be improved.
Perceptual Attention Organization and Processing
The amount of information received from a display is not only dependent on the display presentation but on the operator monitoring the display. The key to successful information processing of multiple signals is parallel processing and time sharing attention resources. Perceptual attention can be thought of as a spotlight. General scanning of a particular display can be thought of as a wide beam search. Then, when there is a need to focus on something in greater detail the spotlight goes into a narrow beam focus. The designer’s objective is to make the display easy to search for important information which will lead to a narrow focus, yet still allow for big picture understanding. This is no easy task!
The ability to exercise supervisory control sampling of a panel while standing a watch is considered an art. If the operator is highly trained, it is assumed that almost all types of casualties can be prevented by observation of trends in the instrumentation readouts. The operator will detect a problem in the infancy stage and proper action can be taken to avoid it from escalating. It is therefore imperative that some optimal sampling rate be developed.
Recently, a study of radiologists having varying degrees of expertise was conducted to determine why some were better than others. The basics of scanning an x-ray are taught at every medical school and hospital in the country. So why is there such a difference in radiologist expertise? The radiologists were not sure of the reason even after sharing their respective techniques. A test was conducted on a series of x-rays where the radiologist’s eye movement patterns were recorded. The results showed that the better doctors had similar scanning techniques that were done on a subconscious level. Developing a scanning pattern that is optimal for a display panel usually takes an operator several years. The Navy should take some of the best operators for all systems (including nuclear) and scan their eye movements to determine an optimal pattern. This pattern would have a twofold benefit. First, it would allow designers to position information identified in the scan pattern in a specific way which would enhance the ease of processing. Second, this pattern could then be used as a prototype to help younger operators.
Another aspect that has a direct impact on the panel is preattentive processing and perceptual organization. By using Gestalt’s efforts to identify a number of basic principles that cause items to be pre-attentively grouped together on a display, instruments that have similar information (i.e., pressure, temperature, flowrates, or bearing, frequency, signal-to-noise ratio) can be grouped together to have a display organization that follows a logical pattern. This approach is extremely helpful when a person is just starting to learn the system. Even if the operator does not know exactly where the instrument reading is located, if the basic outline of the control panel is understood, he will know where to look. It also enhances the ability to parallel process information.
An example would be to have a 3-D holographic display of all ships movement and position parameters. The OOD could immediately orientate the ship with reference to the environment. Environmental parameters such as SVP, fronts and eddies could also be included along with contact solutions so that the OOD could get the big picture in a few seconds. This would enable the OOD to make decisions faster while integrating all information available to the ship in one easy to interpret display. A projection of future position based on changes in parameters (i.e., speed, depth, and/or course) would allow the OOD to see if the decision he just made, or will make, is a safe one and if not allow him time to change it before a catastrophe. The system could even be set to monitor ship status in lieu of the given environment and warn the OOD if he is possibly making an unsafe decision. Many civilian industries use this preventive type of computer aided safety programming.
Another idea for an integrated computer display system would be one for sonar. While at Michigan, I had the opportunity to work with some amazing software products used for sound analysis. Instead of actually having all of the electronic components to make filters, and amplifiers, the program let the components be modeled mathematically in the computer with precision results. Almost all of our sonar processing equipment could be replaced with a computer software program. Imagine all the processing equipment removed and replaced with four or five PCs. The program could interpret the incoming signal faster than a sonar operator could and present to the operator just the vital information minus the noise. Based on the signal received the computer could classify, estimate range (with a series of algorithms based on current sonar and ranging techniques), determine course and speed, resolve bearing ambiguity, determine arrival path, and classify transients all in a second. The sonar operator would have more time to concentrate on just the evaluation of the computer’s interpretation of the signal since the computer is doing more of the work. Additionally, a software drive system would allow more flexibility in the event of a hardware casualty.
Another idea that takes advantage of perceptual organization is that of object displays. There is an illustration in Reference A, demonstrating Stroop’s theory that several dimensions belonging to a single object will guarantee their parallel processing. Applications of Stroop’s theory will improve performance if parallel processing is required and can be related to a system. The figure is an example of related factors in a nuclear reactor.
The base, steady-state operation of the system is illustrated by a standard geometric figure-in this case an octagon. When one of the factors falls out of alignment, this distorts the geometric figure drawing attention to the problem. The distortion can be made in such a way that it then directs the operator’s attention (focusing it) to further indications or controls to correct the problem.
These are just a few ideas on how the improved processing power of the computer can be used to display massive amounts of information in a concise way that will not overload the operator. The applications of these ideas will be examined further in the conclusion.
Spatial Perception. Cognition and Display or Spatial Information
The idea of compatibility between perceptions, as represented on a display, and cognition are very important in ship system displays and nuclear control panels, because if something were to go wrong, the stress factor on the operator explodes exponentially. It is imperative that the compatibility be as close as possible to limit the chance of a mistake. There are countless numbers of instruments that are integral to each other when trying to obtain the status of the ship or reactor. To have the compatibility of proximity, displays that are usually viewed in sequence to ascertain the condition of the system must be located close to each other. There is a problem in the fact that in order to be consistent with display organizational expectations that compatibility of proximity has to suffer a little. It is not possible to put display parameters right next to each other if they are organized by function, there is simply not enough room. So to minimize the impact of non-compatibility of proximity for instruments that are part of an integral evaluation, the displays must be integrated as previously stated, and instrument blocks for similar systems located as close as possible to each other. This way the watch-stander will be monitoring groups of integrated displays in the time it formerly took to view the components that made up a non-integrated display and integrate them mentally.
The net result of all of this, is that by having integral displays organized in a way where compatibility between perceptions, as represented on a display, and cognition are preserved the operator will be able to absorb more information with less chance of error.
These have been just a few ideas in an effort to advocate a more proactive scientific approach to information display systems based on human factors engineering. Finding bottleneck areas of operator performance based on information overload and discovering ways to solve these problems is what a more scientific approach to human factors will give the Submarine Force. It is this type of practical application of human factors theories that has already proven useful to civilian industrial organizations. A great deal of time and money has gone into, and continues to be spent on the development of new systems. The limiting point in these designs is the workload that one operator can handle while stationed at a control panel. Once this workload has been determined, the Submarine Force must engineer solutions to the operator’s limitations, allowing the workload to be increased without a decrease in performance. Human factors engineering is the key component to successful engineering solutions to the information overload problem.
Besides the benefit to the operator, a more proactive role in solving the human factors problems early in the design stage will save money. Manufacturers often live by the concurrent engineering rule of 10. This rule states that it is ten times more expensive to fix a problem once it has gone to the next stage of development. This rule seems to be true also for the development of submarine systems. The information explosion is going to overwhelm operators unless solutions are found. It is cheaper to design them into the systems on paper than to correct the problem after the system is already built. By understanding human perception and processing capabilities it is possible to design displays that present a tremendous amount of information in a concise manner. The key is to let the computer do the work, and then be smart about how the information is displayed, taking full advantage of the graphic processing power of the computer. The only way to accomplish all of the above stated goals is to have a dedicated staff of human factor engineers involved with all aspects of the design process.
Our submarine sailors are the most formally educated, extensively trained, and skilled submariners in the world. We have a one hundred year old legacy of greatness upon which to build. Our Submarine Force constantly handles any challenges that arise. We owe it to the sailors to develop the most modem and comprehensively designed systems possible. With systems designed in such a manner, run by the finest sailors in the world, the Submarine Force will be able to meet and exceed the high standards of past.