Regular Specifications of Resource Requirements for Embedded Control Software

For embedded control systems, a schedule for the allocation of resources to a software component can be described by an infinite word whose ith symbol models the resources used at the ith sampling interval. Dependency of performance on schedules can be formally modeled by an automaton (w-regular language) which captures all the schedules that keep the system within performance requirements. We show how such an automaton is constructed for linear control designs and exponential stability or settling time performance requirements. Then, we explore the use of the automaton for online scheduling and for schedulability analysis. As a case study, we examine how this approach can be applied for the LQG control design. We demonstrate, by examples, that online schedulers can be used to guarantee performance in worst-case condition together with good performance in normal conditions. We also provide examples of schedulability analysis

Robust Stability of Multi-Hop Networks

We propose formal models for analyzing robustness of multi-hop control networks, where data from sensors to controllers and from controllers to actuators is sent through a multi-hop communication network subject to disruptions. When communication disruptions are long, compared to the speed of the control system, we propose to model them as permanent link failures. We show that the complexity of analyzing such failures is NP-hard, and discuss a way to overcome this limitation for practical cases using compositional analysis. For typical packet transmission errors (errors with short time span), we propose a transient error model where links fail for one time slot independently of the past and of other links. We provide sufficient conditions for almost sure stability (stability with probability one) in presence of transient link failures, and give efficient decision procedures. The last part of the paper deals with errors that have random time span. We show that, under some conditions, the permanent failure model can be used as a reliable abstraction

Full immunization coverage and its determinants among children aged 12-23 months in Wogera district, Northwest Ethiopia

AbstractBackground: Immunization is considered one of the most affordable health initiatives for children. Though there is good progress in Ethiopia, the amount of fully vaccinated children, is still below the target. Possible challenges include women having home visits and men’s’ involvement in vaccination uptake. Therefore, this study aimed to determine full immunization coverage and its determinants among children aged 12- 23 months in Wogera districts, Northwest Ethiopia.Aim: This study aimed to determine the full immunization coverage and its determinants among children aged 12-23 months, and to assess the level of immunization coverage and its determinants in Wogera districts, Northwest Ethiopia.Methods: A community-based cross-sectional study was conducted in Wogera district from May 28-June 25/2020. Cluster sampling method was used to recruit 598 study participants. Interviewer administered questionnaire was used to collect data. A bivariable and multivariable logistic regression analysis was done to identify factors associated with full immunization. Odds ratios with 95% Confidence intervals were used to determine significant variables.Results: A total of 584 mothers who had children aged 12-23 months participated in this study. The full immunization coverage was 76.5% (95%CI 73.2-79.8). Mother age >40 years (AOR=7.37, 95% CI: 1.65, 32); mothers who initiate vaccine uptake(woman empowerment) (AOR=1.57, 95% CI: 1.13-2.39); mothers who had 1-3 ANC visit (AOR=2.51, 95% CI:1.14, 5.52), and 4+ ANC follow up (AOR=2.73,95% CI: 1.26, 5.91); r health extension worker's home visit during the first weeks of postpartum period (AOR=1.76,95% CI:1.10, 2.84), and males involved in child immunization (AOR=3.27, 95% CI:1.84, 5.81) was positively associated with being fully vaccinated , however, birth order of 6 and above (AOR=0.35, 95% CI: 0.14, 0.86) was negatively associated with being fully vaccinated.Conclusion: In this study, the full immunization coverage is found to be suboptimal, and it is far from the expected national target coverage. Maternal health care uptake; women empowerment; home visits by HEW during the first week of the postpartum period and male involvement in child immunization were found to be predictors of being fully vaccinated. [Ethiop. J. Health Dev. 2021; 35(SI-3):16-27]Keywords: Full immunization, Children12-23 months, Northwest Ethiopia, Male involvemen

Strategies to revitalize immunization service provision in urban settings of Ethiopia

AbstractBackground: Improving routine immunization in the urban population is an essential element to address immunization coverage and equity. In rural areas, deliberate efforts are made to reach the populations using adapted strategies such as outreaches while specificities of urban populations are generally not considered in immunization programs of Ethiopia.Aim: To explore the barriers and alternative strategies for immunization service provision in urban settings of Ethiopia.Methods: A qualitative study with a phenomenological study design was conducted in selected cities of Addis Ababa, Dire Dawa and Mekele from June to August 2020. Data was collected at different levels of the health system and the community by using a piloted interview guide. Thirty-five key informants and nine in-depth interviews were conducted. Audio-records of interviews were transcribed verbatim, coded and thematic analysis was performed using Open code version 4.02. software.Results: Our finding revealed that the routine immunization service provision strategy in Addis Ababa, Dire Dawa and Mekele cities was a static approach. Service inaccessibility, poor defaulter tracking mechanisms, substandard service in private facilities, shortage of supplies, and lack of training were the main barriers. We explored alternative strategies to revitalize the Expanded Program on Immunization (EPI) including, expanding services to marginalized populations, outreach/home to home service provision, expanding services to private health facilities, and inter-facility linkage through digitalization.Conclusions: The existing immunization service provision strategies in urban settings are not adequate to reach all children. Immunization service inaccessibility and substandard services were the main barriers hindering service provision. Program managers should expand routine service access to marginalized populations through outreach services, by strengthening the public-private partnership, and integrating technological innovations (like digitalization of the EPI program and application of mHealth reminders) to facilitate inter-facility linkage. [Ethiop. J. Health Dev. 2021; 35(SI-3):98-110]Keywords: Immunization, Vaccination, Urban, Revitalize, Private Facility, Ethiopi

How to optimize Immunization Supply Management at different levels of the health system in Oromia Region? An implementation science research

AbstractBackground: In programs like immunization having strong supply management is important to benefit all the necessary inputs of the health system. In Ethiopia, it has been found, that vaccine availability at service delivery points is low. Moreover, the implementation barriers related to Immunization Supply Management are vague at each level of the health system.Aim: This study aimed to explore the practice, barriers and alternative strategies related to immunization supply management in the Oromia region, west Ethiopia.Methods: A phenomenological qualitative approach was used. The data was collected using interview guides among 27 key informants from health posts, health centers, woreda health office, regional hub and Ethiopian Pharmaceutical supply Agency from June 15 to July 10, 2020. All the audio data were independently transcribed verbatim from Amharic and Afaan Oromo languages after repeatedly listening to the records and then translated into the English. The translated transcription documents were imported into Open Code software 4.02 for the purpose of coding. The coding was performed by three experts independently. Thematic analysis was utilized for the analysis of the data.Results: The immunization supply management practices were categorized into three themes: Vaccine forecast, vaccine request & delivery and stock management of vaccines. Organizational (lack of reviewing processes, lack of transportation, lack of refrigerators, interrupted power supply, absence of vaccine forecasting team, unavailability of performance evaluation reports and lack of electricity), technical (lack of standard leger book and lack of vaccine requisition form) and behavioral (lack of accountability, skill gaps and negligence) barriers were the main determinants that affect vaccine availability. The alternative strategies to optimize the ISM include local data-based forecasting, direct delivery of the vaccine to health facilities, transforming the ISM through digitalization and to establish accountability.Conclusion: This study showed that the existing immunization supply management practice is not optimal. Organizational, technical, and behavioral barriers were the identified determinants for low availability. Therefore, program managers and policymakers should emphasize addressing the identified barriers and tailoring the alternative strategies to ensure the availability of vaccines at the point of service delivery. [Ethiop. J. Health Dev. 2021; 35(SI-3):65-74]Keywords: Immunization, Implementation research, Supply Management, Health system, Ethiopi

Automata based interfaces for control and scheduling

Abstract. We propose the use of formal languages of infinite words over the alphabet of task identifiers as an interface between control designs and software implementations. We argue that this approach is more flexible than the classical real-time scheduling framework based on periodic tasks, and allows composition of interfaces by language-theoretic operations. We show that finite automata over infinite words offer analyzable representation and can capture many interesting interface specifications such as exponential stability of switched linear systems.

RTComposer: A Framework for Real-Time Components with Scheduling Interfaces

We present a framework for component-based design and scheduling of real-time embedded software. Each component has a clearly specified interface that includes the methods used for sensing, computation, and actuation, along with a requirement given as a regular set of macro-schedules. Each macro-schedule is an infinite sequence that specifies, for every time slot, the set of component methods invoked in that slot. The macro-scheduler composes the specifications of all the components, along with the platform specification that constrains which methods can be executed within a single slot, to generate a feasible macro-schedule. Within a slot, we use logical execution time semantics, and this microscheduling is implemented on top of a native priority-based scheduler. With this approach, each component can be specified and analyzed in a platform-independent way, and at the same time, the performance can vary with changing load and changing processing speed. We describe an implementation using Real-Time Java. Scheduling specifications can be given as periodic tasks, or using temporal logic, or as omega-automata. Components can be added dynamically, and non-real-time components are allowed. We demonstrate the benefits of the approach using case studies

RTComposer: A framework for real-time components with scheduling interfaces

ABSTRACT We present a framework for component-based design and scheduling of real-time embedded software. Each component has a clearly specified interface that includes the methods used for sensing, computation, and actuation, along with a requirement given as a regular set of macro-schedules. Each macro-schedule is an infinite sequence that specifies, for every time slot, the set of component methods invoked in that slot. The macro-scheduler composes the specifications of all the components, along with the platform specification that constrains which methods can be executed within a single slot, to generate a feasible macro-schedule. Within a slot, we use logical execution time semantics, and this microscheduling is implemented on top of a native priority-based scheduler. With this approach, each component can be specified and analyzed in a platform-independent way, and at the same time, the performance can vary with changing load and changing processing speed. We describe an implementation using Real-Time Java. Scheduling specifications can be given as periodic tasks, or using temporal logic, or as omega-automata. Components can be added dynamically, and non-real-time components are allowed. We demonstrate the benefits of the approach using case studies

Ranking automata and games for prioritized requirements

Abstract. Requirements of reactive systems are usually specified by classifying system executions as desirable and undesirable. To specify prioritized requirements, we propose to associate a rank with each execution. This leads to optimization analogs of verification and synthesis problems in which we compute the “best ” requirement that can be satisfied or enforced from a given state. The classical definitions of acceptance criteria for automata can be generalized to ranking conditions. In particular, given a mapping of states to colors, the Büchi ranking condition maps an execution to the highest color visited infinitely often by the execution, and the cyclic ranking condition with cycle k maps an execution to the modulo-k value of the highest color repeating infinitely often. The well-studied parity acceptance condition is a special case of cyclic ranking with cycle 2, and we show that the cyclic ranking condition can specify all ω-regular ranking functions. We show that the classical characterizations of acceptance conditions by fixpoints over sets generalize to characterizations of ranking conditions by fixpoints over an appropriately chosen lattice of coloring functions. This immediately leads to symbolic algorithms for solving verification and synthesis problems. Furthermore, the precise complexity of a decision problem for ranking conditions is no more than the corresponding acceptance version, and in particular, we show how to solve Büchi ranking games in quadratic time.