Clinicians lack objective means for monitoring if their knee osteoarthritis patients are improving outside of the clinic (e.g., at home). Previous human activity recognition (HAR) models using wearable sensor data have only used data from healthy people and such models are typically imprecise for people who have medical conditions affecting movement. HAR models designed for people with knee osteoarthritis have classified rehabilitation exercises but not the clinically relevant activities of transitioning from a chair, negotiating stairs and walking, which are commonly monitored for improvement during therapy for this condition. Therefore, it is unknown if a HAR model trained on data from people who have knee osteoarthritis can be accurate in classifying these three clinically relevant activities. Therefore, we collected inertial measurement unit (IMU) data from 18 participants with knee osteoarthritis and trained convolutional neural network models to identify chair, stairs and walking activities, and phases. The model accuracy was 85% at the first level of classification (activity), 89–97% at the second (direction of movement) and 60–67% at the third level (phase). This study is the first proof-of-concept that an accurate HAR system can be developed using IMU data from people with knee osteoarthritis to classify activities and phases of activities.

Asset management is a strategic tool for maintaining the value of an asset at a level that is satisfactory for users, asset owners, and taxpayers. This paper introduces the concept of service value. The concept is applied following the recommendations of the Organisation for Economic Co-operation and Development (OECD): service value equals the value of economic benefits generated by an asset. It is shown how alternative value accounting methods result in different asset values. The present value method, as recommended by accounting practitioners and in line with the concept of service value, is more appropriate for asset management purposes than the perpetual inventory method (PIM), despite the fact that the latter is more widely used. The impact of correct asset and service value accounting extends well beyond project and investment program management levels to the national accounting system of fixed capital. Incorrect asset management accounting may lead to serious under- or overestimation of investments and repair debt.