scholarly journals A Hybrid Automata Approach for Monitoring the Patient in the Loop in Artificial Pancreas Systems

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7117
Author(s):  
Aleix Beneyto ◽  
Vicenç Puig ◽  
B. Wayne Bequette ◽  
Josep Vehi

The use of automated insulin delivery systems has become a reality for people with type 1 diabetes (T1D), with several hybrid systems already on the market. One of the particularities of this technology is that the patient is in the loop. People with T1D are the plant to control and also a plant operator, because they may have to provide information to the control loop. The most immediate information provided by patients that affects performance and safety are the announcement of meals and exercise. Therefore, to ensure safety and performance, the human factor impact needs to be addressed by designing fault monitoring strategies. In this paper, a monitoring system is developed to diagnose potential patient modes and faults. The monitoring system is based on the residual generation of a bank of observers. To that aim, a linear parameter varying (LPV) polytopic representation of the system is adopted and a bank of Kalman filters is designed using linear matrix inequalities (LMI). The system uncertainty is propagated using a zonotopic-set representation, which allows determining confidence bounds for each of the observer outputs and residuals. For the detection of modes, a hybrid automaton model is generated and diagnosis is performed by interpreting the events and transitions within the automaton. The developed system is tested in simulation, showing the potential benefits of using the proposed approach for artificial pancreas systems.

Nutrients ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 2322
Author(s):  
Kaitlyn M. Eck ◽  
Carol Byrd-Bredbenner

Limited research has examined athletes’ food and health beliefs and decisions and the congruence of these decisions with recommendations from nutrition professionals. This study aimed to improve understanding of athletes’ food-related beliefs and practices to enable nutrition professionals to more effectively enhance performance while protecting athletes’ health. Division I college athletes (n = 14, 64% female) from a variety of sports were recruited to participate in 20-min semi-structured phone interviews about food and nutrition-related behaviors and cognitions. Data were content analyzed to identify themes and trends. Prominent factors influencing athletes’ food choices were potential benefits to health and performance, availability of foods, and recommendations from sports dietitians. Foods commonly consumed by athletes, including fruits, vegetables, and lean protein, were generally healthy and aligned with sports nutrition recommendations. Athletes avoided energy-dense nutrient-poor foods, such as fast food and fried foods, with the goal of improving performance. Some athletes took supplements (i.e., multivitamin, iron, protein) on the premise that they would improve health and enhance performance or recovery. While athletes’ nutrition behaviors are generally congruent with current recommendations, findings highlighted misconceptions held by athletes related to the benefits of some supplements and the belief that packaged/processed foods were inherently less healthy than other options. Nutrition misconceptions held by athletes and incongruities between athletes’ nutrition knowledge and behaviors suggest that dietitians should aim to dispel misconceptions held by athletes and provide additional guidance and information to support athletes’ current healthful behaviors to ensure these behaviors extend beyond their college athletic career.


2020 ◽  
Vol 13 (6) ◽  
pp. 673-678
Author(s):  
Wynand Jacobus van der Merwe Steyn

AbstractThe world is becoming a hyper-connected environment where an abundance of data from sensor networks can provide continuous information on the behaviour and performance of infrastructure. The last part of the 3rd Industrial Revolution (IR) and the start of the 4th IR gave rise to a world where this overabundance of sensors, and availability of wireless networks enables connections between people and infrastructure that was not practically comprehensible during the 20th century. 4IR supports the datafication of life, data science, big data, transportation evolution, optimization of logistic and supply chains and automation of various aspects of life, including vehicles and road infrastructure. The hyper-connected 4IR environment allows integration between the physical world and digital and intelligent engineering, increasingly serving as the primary lifecycle management systems for engineering practitioners. With this background, the paper evaluates a few concepts of the hyper-connected pavement environment in a 4IR Digital Twin mode, with the emphasis on selected applications, implications, benefits and limitations. The hyper-connected world can and should be managed in the pavement realm to ensure that adequate and applicable data are collected regarding infrastructure, environment and users to enable a more efficient and effective transportation system. In this regard, and planning for future scenarios where the proliferation of data is a given, it is important that pavement engineers understand what is possible, evaluate the potential benefits, conduct cost/benefit evaluations, and implement appropriate solutions to ensure longevity and safety of pavement infrastructure.


Author(s):  
Lee-Huang Chen ◽  
Kyunam Kim ◽  
Ellande Tang ◽  
Kevin Li ◽  
Richard House ◽  
...  

This paper presents the design, analysis and testing of a fully actuated modular spherical tensegrity robot for co-robotic and space exploration applications. Robots built from tensegrity structures (composed of pure tensile and compression elements) have many potential benefits including high robustness through redundancy, many degrees of freedom in movement and flexible design. However to fully take advantage of these properties a significant fraction of the tensile elements should be active, leading to a potential increase in complexity, messy cable and power routing systems and increased design difficulty. Here we describe an elegant solution to a fully actuated tensegrity robot: The TT-3 (version 3) tensegrity robot, developed at UC Berkeley, in collaboration with NASA Ames, is a lightweight, low cost, modular, and rapidly prototyped spherical tensegrity robot. This robot is based on a ball-shaped six-bar tensegrity structure and features a unique modular rod-centered distributed actuation and control architecture. This paper presents the novel mechanism design, architecture and simulations of TT-3, the first untethered, fully actuated cable-driven six-bar tensegrity spherical robot ever built and tested for mobility. Furthermore, this paper discusses the controls and preliminary testing performed to observe the system’s behavior and performance.


2009 ◽  
Vol 2009 ◽  
pp. 1-7 ◽  
Author(s):  
Selma Ben Attia ◽  
Salah Salhi ◽  
Mekki Ksouri

This paper concerns static output feedback design of discrete-time linear switched system using switched Lyapunov functions (SLFs). A new characterization of stability for the switched system under arbitrary switching is first given together with -performance evaluation. The various conditions are given through a family of LMIs (Linear Matrix Inequalities) parameterized by a scalar variable which offers an additional degree of freedom, enabling, at the expense of a relatively small degree of complexity in the numerical treatment (one line search), to provide better results compared to previous one. The control is defined as a switched static output feedback which guarantees stability and -performance for the closed-loop system. A numerical example is presented to illustrate the effectiveness of the proposed conditions.


2005 ◽  
Vol 51 (9) ◽  
pp. 31-37 ◽  
Author(s):  
B. Shutes ◽  
J.B. Ellis ◽  
D.M. Revitt ◽  
L.N.L. Scholes

This paper presents the outcome of an inventory of planted wetland systems in the UK which are classified according to land use type and are all examples of sustainable drainage systems. The introduction of constructed wetlands to treat surface runoff essentially followed a 1997 Environment Agency for England and Wales report advocating the use of “soft engineered” facilities including wetlands in the context of sustainable development and Agenda 21. Subsequently published reports by the UK Construction Industry Research and Information Association (CIRIA) have promoted the potential benefits to both developer and the community of adopting constructed wetlands and other vegetated systems as a sustainable drainage approach. In addition, the UK Environment Agency and Highways Agency (HA) have recently published their own design criteria and requirements for vegetative control and treatment of road runoff. A case study of the design and performance of a constructed wetland system for the treatment of road runoff is discussed. The performance of these systems will be assessed in terms of their design criteria, runoff loadings as well as vegetation and structure maintenance procedures. The differing design approaches in guidance documents published in the UK by the Environment Agency, CIRIA and HA will also be evaluated.


2015 ◽  
Vol 12 (2) ◽  
pp. 655-681 ◽  
Author(s):  
Tomas Cerny ◽  
Miroslav Macik ◽  
Michael Donahoo ◽  
Jan Janousek

Increasing demands on user interface (UI) usability, adaptability, and dynamic behavior drives ever-growing development and maintenance complexity. Traditional UI design techniques result in complex descriptions for data presentations with significant information restatement. In addition, multiple concerns in UI development leads to descriptions that exhibit concern tangling, which results in high fragment replication. Concern-separating approaches address these issues; however, they fail to maintain the separation of concerns for execution tasks like rendering or UI delivery to clients. During the rendering process at the server side, the separation collapses into entangled concerns that are provided to clients. Such client-side entanglement may seem inconsequential since the clients are simply displaying what is sent to them; however, such entanglement compromises client performance as it results in problems such as replication, fragment granularity ill-suited for effective caching, etc. This paper considers advantages brought by concern-separation from both perspectives. It proposes extension to the aspect-oriented UI design with distributed concern delivery (DCD) for client-server applications. Such an extension lessens the serverside involvement in UI assembly and reduces the fragment replication in provided UI descriptions. The server provides clients with individual UI concerns, and they become partially responsible for the UI assembly. This change increases client-side concern reuse and extends caching opportunities, reducing the volume of transmitted information between client and server to improve UI responsiveness and performance. The underlying aspect-oriented UI design automates the server-side derivation of concerns related to data presentations adapted to runtime context, security, conditions, etc. Evaluation of the approach is considered in a case study applying DCD to an existing, production web application. Our results demonstrate decreased volumes of UI descriptions assembled by the server-side and extended client-side caching abilities, reducing required data/fragment transmission, which improves UI responsiveness. Furthermore, we evaluate the potential benefits of DCD integration implications in selected UI frameworks.


Author(s):  
Nola Hewitt-Dundas ◽  
Stephen Roper

There is now considerable empirical evidence demonstrating the innovation and performance benefits that accrue to firms engaging in open innovation (OI). Here, we use novel data on micro-businesses to show that the average level of engagement in OI falls well below the optimal level, a finding that reflects that of other empirical studies. We identify and examine three market failures which may help to explain this result. These relate to a lack of understanding of the potential benefits of OI by firms, a lack of information about the capabilities of potential partners and a lack of information about the trustworthiness of potential partners. Our findings provide evidence that policy initiatives designed to offset these information failures are likely to increase the range of partners with which firms engage with significant benefits for innovation.


2021 ◽  
Vol 39 (2A) ◽  
pp. 268-279
Author(s):  
Safa F. Fadhel ◽  
Safanah M. Raafat

The Bergman model is one of the most commonly used models applied to the representation of the artificial pancreas (AP). It is important to study the effects of the insulin infusion on blood glucose concentration. This work includes a case study for the design of a robust controller for an AP. Robustness is a structured control that improves a system's ability to keep its stability and performance under various conditions. The proposed H∞ loop shaping HLS method will fulfill the design requirements of robust control and performance. The results of the simulation prove the superiority of the intended approach in terms of simple structure, robust performance, and stability with the least control effort


2013 ◽  
Vol 23 (2) ◽  
pp. 169-186 ◽  
Author(s):  
Anna Filasová ◽  
Daniel Gontkovič ◽  
Dušan Krokavec

The paper is engaged with the framework of designing adaptive fault estimation for linear continuous-time systems with distributed time delay. The Lyapunov-Krasovskii functional principle is enforced by imposing the integral partitioning method and a new equivalent delaydependent design condition for observer-based assessment of faults are established in terms of linear matrix inequalities. Asymptotic stability conditions are derived and regarded with respect to the incidence of structured matrix variables in the linear matrix inequality formulation. Simulation results illustrate the design approach, and demonstrates power and performance of the actuator fault assessment.


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