The present paper describes a system for older people to self-administer the 30-s chair stand test (CST) at home without supervision. The system comprises a low-cost sensor to count sit-to-stand (SiSt) transitions, and an Android application to guide older people through the procedure. Two observational studies were conducted to test (i) the sensor in a supervised environment (n = 7; m = 83.29 years old, sd = 4.19; 5 female), and (ii) the complete system in an unsupervised one (n = 7; age 64–74 years old; 3 female). The participants in the supervised test were asked to perform a 30-s CST with the sensor, while a member of the research team manually counted valid transitions. Automatic and manual counts were perfectly correlated (Pearson’s r = 1, p = 0.00). Even though the sample was small, none of the signals around the critical score were affected by harmful noise; p (harmless noise) = 1, 95% CI = (0.98, 1). The participants in the unsupervised test used the system in their homes for a month. None of them dropped out, and they reported it to be easy to use, comfortable, and easy to understand. Thus, the system is suitable to be used by older adults in their homes without professional supervision.

Lower-limb strength is a marker of functional decline in elders. This work studies the feasibility of using the quasi-periodic nature of the distance between a subjects’ back and the chair backrest during a 30-s chair–stand test (CST) to carry out unsupervised measurements based on readings from a low-cost ultrasound sensor. The device comprises an ultrasound sensor, an Arduino UNO board, and a Bluetooth module. Sit-to-stand transitions are identified by filtering the signal with a moving minimum filter and comparing the output to an adaptive threshold. An inter-rater reliability (IRR) study was carried out to validate the device ability to count the same number of valid transitions as the gold-standard manual count. A group of elders (age: mean (m) = 80.79 years old, SD = 5.38; gender: 21 female and seven male) were asked to perform a 30-s CST using the device while a trained nurse manually counted valid transitions. Ultimately, a moving minimum filter was necessary to cancel the effect of outliers, likely produced because older people tend to produce more motion artefacts and, thus, noisier signals. While the intra-class correlation coefficient (ICC) for this study was good (ICC = 0.86, 95% confidence interval (CI) = 0.73, 0.93), it is not yet clear whether the results are sufficient to support clinical decision-making.

Population aging threatens the sustainability of welfare systems since it is not accompanied by an extended healthy and independent period in the last years of life. The Comprehensive Geriatric Assessment (CGA) has been shown to be efficient in maintaining the healthy period at the end of the life. Frailty monitoring is typically carried out for an average period of 6 months in clinical settings, while more regular monitoring could prevent the transition to disability. We present the design process of a system for frailty home monitoring based on an adapted CGA and the rationale behind its User eXperience (UX) design. The resulting home monitoring system consists of two devices based on ultrasound sensors, a weight scale, and a mobile application for managing the devices, administering CGA-related questionnaires, and providing alerts. Older users may encounter barriers in their usage of technology. For this reason, usability and acceptability are critical for health monitoring systems addressed to geriatric patients. In the design of our system, we have followed a user-centered process, involving geriatricians and older frail patients by means of co-creation methods. In the iterative process of design and usability testing, we have identified the most effective way of conducting the home-based CGA, not just by replicating the dialogue between the physician and the patient, but by adapting the design to the possibilities and limitations of mobile health for this segment of users. The usability evaluation, carried out with 14 older adults, has proved the feasibility of users older than 70 effectively using our monitoring system, additionally showing an intention over 80% for using the system. It has also provided some insights and recommendations for the design of mobile health systems for older users.

Nowadays, visualization of large amounts of data has become a key issue for processing data in many fields. This paper presents a conceptual model for describing information visualization systems. This conceptual model has been represented using the Unified Modeling Language, therefore it takes advantage of the understandability, unambiguity, flexibility, and adaptability provided by this notation. The proposed model outlines concepts such as visualization workspace, device, visual representation and its features, information visualization task and its effects on visualization, inter-item relationship, etc. The main applications of the proposed model are: (1) to guide the development of a new visualization system by specifying which are the main concepts that have to be considered and how they relate to each other; (2) to characterize or describe an already existing visualization system; and (3) to thoroughly compare existing visualization systems. To illustrate the use and applications of the model, several examples of information visualization systems are provided.

abst r a ctThe information-seeking process carried out by researchers is complex and full of differ-ent variables. We have represented this complexity for computer science researchers in the form of a conceptual model. The model is presented in a visual form using the UML mod-eling language, since it allows conveying all the complexity present in such a process with greater clarity. It has been obtained after carrying out two qualitative studies -a focus group and semi-structured interviews-with computer science researchers. The proposed overall model is composed of 4 sub-models: of the documents used in the process, of the tasks undertaken, of the user, and of the information-seeking process context. The concep-tual model proposed can serve for the purpose of better understanding the information-seeking process, for example for librarians or for software designers wanting to provide a support to such task. It can also be useful as a framework to characterize different software solutions aimed to information-seeking in research activities, and to compare them.