Yeti Li

Automated Rehabilitation System: Movement Measurement and Feedback for Patients and Physiotherapists in the Rehabilitation Clinic

In current physical rehabilitation protocols, patients typically perform exercises with intermittent feedback or guidance following the initial demonstrations from the physiotherapist. Although many patient-centered systems have been developed for home rehabilitation, few systems have been developed to aid the physiotherapist as well as patients in the rehabilitation clinic. This article proposes the Automated Rehabilitation System (ARS), a system designed specifically for rehabilitation clinics using an iterative design process, developed with physiotherapists and patients in a knee and hip replacement clinic. ARS consists of body-worn inertial measurement units that continuously measure the patient’s pose. The measured pose is graphically represented as an animation and overlaid with the instructed motion on a visual display shown to the patient during exercise performance. ARS allows physiotherapists to quantitatively measure patient movement, assess recovery progress, and manage and schedule exercise regimens for patients. The system requirements and design requirements were derived through a focus group with 13 physiotherapists. For patients, ARS provides visual feedback and a novel exercise guidance feature to aid them while exercising. The patient interface was evaluated in a user study with 26 outpatients. The results show that performing the exercises with the visual guidance tool improves the quality of exercise performance.

Understanding Automated Financial Trading Using Work Domain Analysis

Finance is a complex domain largely unexplored in the human factors literature. Modern financial trading systems involve a variety of coupled socio-technical systems (e.g. humans and technologies) and have become highly automated. Recent stock market crashes, such as the well-known Flash Crash, show automation-initiated dynamics. This suggests that a human factors understanding of this environment may be useful. In this article, we report an initial attempt to model buyer-side Automated Trading (AT) systems using a Cognitive Work Analysis (CWA) approach. A Work Domain Analysis (WDA) model is presented to describe the automated financial trading domain. This work has implications for applying CWA to finance but also advances the understanding of how to model a highly automated domain.

Modeling Automation With Cognitive Work Analysis to Support Human-Automation Coordination

Cognitive work analysis is useful to develop displays for complex situations, but it has not been well explored in providing support for human-automation coordination. To fill this gap, we propose a degree of automation (DOA) layering approach, demonstrated by modeling an automated financial trading domain, with a goal of supporting interface design in this domain. The abstraction hierarchy and the decision ladder each adopted an additional layer, mapping functions allocated to the trader and to the automation. In addition to the mapping, we marked the four stages of automation on the decision ladder to provide guidance on representing the function allocation at the task level. Next, we compared the DOA layering approach to how automation was represented in the cognitive work analysis literature. We found that a DOA-layered decision ladder, which included well-developed knowledge of the stages and levels of automation, can be suited to modern automated systems with different DOAs. This study suggests that the DOA layering approach has important implications for designing automation displays and deciding stages and levels of automation and may be a useful approach for modeling adaptive automation.

Ecological Interface Design for Knee and Hip Automatic Physiotherapy Assistant and Rehabilitation System

In this paper, we report on a recent interface design and evaluation process for a new knee and hip automatic physiotherapy assistant and rehabilitation system (ARS). Interface design was concurrent with the development of ARS. The ARS has the potential to improve the automation of rehabilitation treatments, by providing quantitative measures of a patient’s motion. However, the complexity of rehabilitation information available to the therapist has increased with this additional information. We applied Ecological Interface Design (EID) to understand the domain of physiotherapy and the role of the automation. Results of a Work Domain Analysis (WDA) revealed new functions and constraints in rehabilitation now accessible through the ARS, and provided the design requirements for interface design. A novel interface was designed which is currently undergoing evaluation to see if it improves the quality and experience of physiotherapy. This study provides an example of the advantages of using EID at the early phase of design, and how to apply EID to a system of increasing automaticity.

Representing Stages and Levels of Automation on a Decision Ladder: The Case of Automated Financial Trading

We propose that representing stages and levels of automation on a decision ladder (DL) could help to identify information requirements for designing automation interfaces. We look at automated financial trading systems, a domain with variable degrees of automation (DOA). We give examples of modelling a financial trading task for two DOAs: basket trading (a low DOA) and trend following trading (a high DOA). On the resulting DLs, both human and automated information-processing activities are presented. The steps and states of knowledge allocated to automation are first categorized by the commonly known four stages of automation, and then shaded to represent the level of automation in each stage. This work advances the understanding of automated trading, and automation in general, and may provide a deeper representation of human-automation interactions and thus better understanding of design requirements.

To Cross or Not to Cross: Urgency-Based External Warning Displays on Autonomous Vehicles to Improve Pedestrian Crossing Safety

Autonomous vehicles (AV) may be able to show visual displays on their external surface to support pedestrian communication with the AV. Pedestrian crossing at uncontrolled locations is safety-critical and clear communication between the pedestrian and the AV is important in this situation. However, research to date has not been clear on how the AV should communicate with pedestrians. We designed two sets of warnings on AVs based on the perception of warning urgency. Each set consisted of three warnings that differed in color and flashing pattern and indicated distinct safety-related information. A survey was conducted to investigate how people make decisions, warnings within and outside of the driving context, and perceived warning compliance. Results showed that people were risk averse in crossing and cars with warning displays were perceived as more urgent. This paper contributes uniquely in exploring research-based approaches on designing warnings to improve pedestrian crossing safety.

Improved Monitoring Performance of Financial Trading Algorithms Using a Graphical Display

Ecological Interface Design (EID) has been applied to financial trading to derive graphical forms from work analysis models to improve monitoring performance. Automated trading requires contextual support for monitoring algorithm failures, and we designed a graphical, hybrid display inspired by EID to provide such support. We report a two-stage experiment involving a pilot study and a formal study to evaluate the hybrid display with participants who have a basic understanding of computer algorithms. The pilot study used an initial version of the trading algorithm. The formal study used similar apparatus but a modified algorithm. Results showed that the hybrid display provided better support than the conventional display for detecting algorithm failures only when the contextual support provided by the conventional and the representational visualizations was consistent. Further, we discuss the compatibility issue in designing hybrid displays.

Multimodal Displays for Enhancing Performance in a Supervisory Monitoring Task: Reaction Time to Detect Critical Events

This study investigated the efficacy of a multimodal display ground control station (GCS) for the control of an unmanned aerial vehicle (UAV) to convey system faults and environmental hazards. The participant’s task was to fly a short UAV mission, detect critical events, and land safely in possibly strong turbulence and wind shear. While monitoring for critical events, the participant also carried out a secondary task. The GCS simulator was equipped with an auditory display that provided information on engine revolutions per minute (RPM), and a tactile display that provided information on attitude upset. Multiple performance measures were used to determine whether the auditory display and tactile display improved monitoring performance relative to a visual-only GCS display. Results showed that the auditory display resulted in significantly faster reaction times to detect critical events in engine RPM. However, the tactile display did not add any benefit to warn participants of attitude upset. The results should help further the understanding of multimodal display effectiveness to enhance situation awareness for improving operator efficiency on monitoring tasks in complex systems.