Remote patient monitoring should reduce mortality rates, improve care, and reduce costs. We present an overview of the available technologies for the remote monitoring of chronic obstructive pulmonary disease (COPD) patients, together with the most important medical information regarding COPD in a language that is adapted for engineers. Our aim is to bridge the gap between the technical and medical worlds and to facilitate and motivate future research in the field. We also present a justification, motivation, and explanation of how to monitor the most important parameters for COPD patients, together with pointers for the challenges that remain. Additionally, we propose and justify the importance of electrocardiograms (ECGs) and the arterial carbon dioxide partial pressure (PaCO2) as two crucial physiological parameters that have not been used so far to any great extent in the monitoring of COPD patients. We cover four possibilities for the remote monitoring of COPD patients: continuous monitoring during normal daily activities for the prediction and early detection of exacerbations and life-threatening events, monitoring during the home treatment of mild exacerbations, monitoring oxygen therapy applications, and monitoring exercise. We also present and discuss the current approaches to decision support at remote locations and list the normal and pathological values/ranges for all the relevant physiological parameters. The paper concludes with our insights into the future developments and remaining challenges for improvements to continuous remote monitoring systems. Graphical abstractᅟ

This paper completes the proof of the group configuration theorem for simple theories started in [1]. We introduce the notion of an almost hyperdefinable (poly-)structure, and show that it has a reasonable model theory. We then construct an almost hyperdefinable group from a polygroup chunk.

The recent trend in electrocardiogram (ECG) device development is towards wireless body sensors applied for patient monitoring. The ultimate goal is to develop a multi-functional body sensor that will provide synchronized vital bio-signs of the monitored user. In this paper, we present an ECG sensor for long-term monitoring, which measures the surface potential difference between proximal electrodes near the heart, called differential ECG lead or differential lead, in short. The sensor has been certified as a class IIa medical device and is available on the market under the trademark Savvy ECG. An improvement from the user's perspective-immediate access to the measured data-is also implemented into the design. With appropriate placement of the device on the chest, a very clear distinction of all electrocardiographic waves can be achieved, allowing for ECG recording of high quality, sufficient for medical analysis. Experimental results that elucidate the measurements from a differential lead regarding sensors' position, the impact of artifacts, and potential diagnostic value, are shown. We demonstrate the sensors' potential by presenting results from its various areas of application: medicine, sports, veterinary, and some new fields of investigation, like hearth rate variability biofeedback assessment and biometric authentication.Sensors 2020, 20, 1695 2 of 17 have evolved into smaller and more powerful devices for recording high-quality single or multi-lead ECG, they cause discomfort for the patients because the device needs to be carried on the body with all the cabling. Furthermore, they still have limited duration of the recordings up to a maximum of 14 days. On the other hand, the (wireless) ILRs are lightweight devices (usually only around 17 g weight) implanted under the skin [5] and provide comfortable long-term ECG monitoring for up to several years. However, the ILRs are invasive devices and their capacity for ECG recording is limited to several recordings, each with a duration of a couple of minutes. Consequently, if the patient equipped with the device does not visit a medical office to retrieve the measurements in a timely manner, older recordings are overwritten.The provision of mobile health (mHealth) services, like patient monitoring in hospitals [6], remote medical support, or monitoring during sport activities, requires for these ECG devices to allow greater patient mobility than the Holter monitor [7-9] and additionally provide wireless transmission of the data from the device to a nearby personal terminal (smartphone, tablet) connected to the Internet [10]. Motivated by these challenges, we have envisioned to design a monitoring system for synchronous measurement of vital bio-signs [11,12]. Our ultimate goal was to combine minimal number of body sensors with different functions into in a single one, i.e., to develop a multi-functional body sensor. Namely, our long-term experience with MECG devices has shown us that a significant amount of information about vital functions, including ECG, can be...

Systems with reduced numbers of leads that can synthesize the 12-lead electrocardiogram (ECG) with an insignificant or a small loss of diagnostic information have been proposed. The advantage over standard 12-lead ECG systems is the smaller number of measurement sites (i.e., electrodes) and, consequently, fewer wires. In this paper, we review all the important systems with reduced numbers of leads together with the methodology for synthesizing the leads. The fundamental theoretical background necessary to understand the most important concepts related to the synthesis is included. The presented theoretical and experimental justifications for the synthesis show that it is not necessary to measure a large number of leads directly, because the standard 12-lead ECG and arbitrary additional leads can be synthesized. Various approaches to evaluating the synthesized 12-lead ECG are defined and explained, and a number of systems that synthesize 12-lead ECG are presented as they were introduced in the literature. We cover the developments and improvements from the 1940s to the present day. The systems are classified on the basis of the synthesis method used, the approach to the evaluation of the synthesized ECG (depending on the measurement sites used), and on the number and types of leads employed. Based on a detailed assessment of state-of-the-art systems, open problems and challenges are highlighted, while further developments of electrocardiographic systems are envisaged.

We prove a function-field version of Chebotarev's density theorem in the framework of difference algebraic geometry by developing the notion of Galois coverings of generalized difference schemes, and using Hrushovski's twisted Lang-Weil estimate.We consider our approach to generalized difference algebra a major advance in its own right, and it should be of intrinsic interest in the difference algebra community. In view of the fact that the work of Wibmer [22] can be rewritten and possibly slightly sharpened using generalized difference algebra, as well as the elaborate study of generalized difference extensions along the lines of [20], we envisage applications in Galois theory of difference equations.Moreover, there are other naturally occurring contexts where it may be advantageous to study objects with several endomorphisms. In particular, as Tom Scanlon pointed out, a key step in most approaches to Manin-Mumford conjecture ([11], for example) is to find a difference polynomial equation that captures all the relevant torsion points, which is very hard to achieve with a single endomorphism. On the other hand, it is much easier to capture all of the torsion if one uses two endomorphisms.Apart from number theory and algebraic geometry, our results (especially Theorem 4.27) should be of interest in model-theory and logic since, in conjunction with the description of definable sets in terms of Galois stratifications from [20], they reduce the problem of counting points on definable sets over fields with powers of Frobenius to a calculation of (twisted) character sums. Thus, the present paper can be viewed as a conceptualization of ideas of [3,17] for fields with Frobenii. As already mentioned, Theorem 4.27 and its consequence Corollary 4.28 are used in our subsequent work on Galois stratifications in [20]. Generalized difference schemesIn this section, we wish to broaden the class of difference schemes in order to allow certain Galois actions. We shall henceforth refer to difference schemes with a single endomorphism as discussed in [12,13] as strict, or ordinary difference schemes, and we shall expand the term 'difference scheme' to include objects with multiple endomorphisms. Following a suggestion by the referee, we removed a number of highly technical verifications to make this section more readable. We direct the interested reader to the details [19].2.