# Cognitive Principles for Remote Condition Monitoring Applied to a Rail Pantograph System
## 2 Background
### Cognition for Remote Condition Monitoring  
The role that a user interface plays in an RCM system is to take the data recorded by sensors, which are potentially uninterpretable by the user, and translate them into information in a form that the human user can understand and utilise in decision making [31]. The amount of useful information that can be extracted from the data is directly linked to the efficiency by which this transformation occurs. Because of this, a Human-Machine Interface (HMI) is required, with the cognitive process of the user being a key consideration. An accurate understanding of what the user requires of the system provides a strong foundation upon which the design can be built. The system designed in this project could be described as a joint cognitive system, one in which the human user and system work together to achieve the desired goal [32]. Designing a system with the users' goals and needs at the forefront can increase productivity whilst making tasks easier to understand, reducing cognitive load and stress experienced [33]. ISO-9241-210 [33] outlines the principles of human-centred design, and the process by which user understanding can be successfully embedded within design. This is a five-stage process involving planning of the project, understanding context of use, specifying requirements, designing the interface, and evaluation. While valuable, the approach is general to any technology or product development. In terms of context and fundamental requirements, work has already been conducted to observe operators in maintenance control environments to understand the cognitive stages that need to be reflected in the operation of RCM technologies. Based on a cognitive model of alarm response, it was identified in [11] that there are four high-level activities in the process of fault handling of railway assets. Firstly, the user must acknowledge the presence of an alarm; this stage is named \"notification\". Once the user is aware of the alarm, they must determine the validity of the event. This stage of verification is called the \"acceptance\" stage. After verifying the fault, the operator must analyse the available information to determine the cause of the fault. In this stage, \"analysis\", it was identified that contextual information, such as recent history of faults at that location, was a particularly useful type of information [11]. The final stage, \"clearance\", involves the user selecting the optimum method of dealing with the fault. After a plan for rectifying the fault has been made, the event can be 'cleared'. These four stages could be considered four major decisions the operator needs to make before they can move on to the next fault, these decisions being:  
1. Is there a fault? 2. Is the fault legitimate? 3. What was the cause of the fault? 4. What should be done about the fault? These stages may vary in relevance depending on the domain, task and information needs of any RCM use case [11; 32]. This may be particularly the case where there is insufficient information. Heuristic strategies such as extrapolating from previous incidents or making judgements based on the frequency of previous events may support problem solving, but also may lead the user to erroneous conclusions. Equally, too much information can lead to strategies such as reducing the precision of decision making, or filtering out certain categories of event or information that may be seen as less relevant or pressing. Therefore, the HMI design must be conscious of the need to support effective processing of information and guarding against inappropriate conclusions. A strategic approach to supporting decision-making through cognitively staged HMIs may alleviate these issues.