The Alpha of Indulgent Consensus

This paper presents a simple framework unifying a family of consensus algorithms that can tolerate process crash failures and asynchronous periods of the network, also called indulgent consensus algorithms. Key to the framework is a new abstraction we introduce here, called Alpha, and which precisely captures consensus safety. Implementations of Alpha in shared memory, storage area network, message passing and active disk systems are presented, leading to directly derived consensus algorithms suited to these communication media. The paper also considers the case where the number of processes is unknown and can be arbitrarily larg

Generating Fast Indulgent Algorithms

Synchronous distributed algorithms are easier to design and prove correct than algorithms that tolerate asynchrony. Yet, in the real world, networks experience asynchrony and other timing anomalies. In this paper, we address the question of how to efficiently transform an algorithm that relies on synchronous timing into an algorithm that tolerates asynchronous executions. We introduce a transformation technique from synchronous algorithms to indulgent algorithms (Guerraoui, in PODC, pp. 289-297, 2000), which induces only a constant overhead in terms of time complexity in well-behaved executions. Our technique is based on a new abstraction we call an asynchrony detector, which the participating processes implement collectively. The resulting transformation works for the class of colorless distributed tasks, including consensus and set agreement. Interestingly, we also show that our technique is relevant for colored tasks, by applying it to the renaming problem, to obtain the first indulgent renaming algorith

You Only Live Multiple Times: A Blackbox Solution for Reusing Crash-Stop Algorithms In Realistic Crash-Recovery Settings

Distributed agreement-based algorithms are often specified in a crash-stop asynchronous model augmented by Chandra and Toueg\u27s unreliable failure detectors. In such models, correct nodes stay up forever, incorrect nodes eventually crash and remain down forever, and failure detectors behave correctly forever eventually, However, in reality, nodes as well as communication links both crash and recover without deterministic guarantees to remain in some state forever. In this paper, we capture this realistic temporary and probabilitic behaviour in a simple new system model. Moreover, we identify a large algorithm class for which we devise a property-preserving transformation. Using this transformation, many algorithms written for the asynchronous crash-stop model run correctly and unchanged in real systems

Community Issues and the Bioeconomy Transition: Moving Independence from Imported Oil and Climate Change Up the Local Policy Agenda

Many issues and some myths are drivers of change in the emerging transition to a bioeconomy.�� This working paper focuses on two of the key drivers in much of the discussion and they are not likely to disappear from the agenda anytime soon. First is the broad based national priority for reducing domestic dependence on imported oil.� Second is the emergence of the global concern over climate change and mitigation of greenhouse gas emissions.� A framework for local policy decisions is developed for each issue using the alternatives and consequences approach. �

Business ethics in TQM : the qualities and spectrum zones of a case illustration

Purpose - The objective of this research is to introduce and describe a conceptual framework of business ethics in TQM.Design/methodology/approach - In order to highlight the concepts proffered, a case study in the Swedish retail industry was conducted. The data that underpin the case illustration have been collected as part of a larger research project in the Swedish retail industry. Draws on and reports the findings from one case of the larger research project that has been used in this instance to inform the role of business ethics in TQM. The case illustration is based on a qualitative approach. The data were collected through interviews with leading executives in the corporation,Findings - Both time and context become crucial parameters to manage the quality and spectrum zones of core values in the marketplace. In fact, the necessary quality management of business operations has to be performed without delay, minimising the damage. Therefore, the importance of business ethics becomes evident in TQM. In the long run, TQM will not succeed in business operations unless business ethics is considered in the core values to support the techniques and tools applied.Research limitations/implications - The model has only been tested by relating it to one case in the Swedish retail industry.Practical implications - TQM is dependent on the contextual and evolutionary issues in the marketplace. Therefore, TQM should be interpreted as a continuous process. The importance of continuously monitoring the spectrum zones and qualities of core values in TQM should not be under-estimated. Therefore, business ethics should always be present in TQM. Further research would benefit from other case studies of how business ethics benefits TQM. Therefore, the dynamics of business ethics in TQM should be further explored.Originality/value - Business ethics needs to be an essential consideration of any TQM process. Examines how an organization can incorporate this task.<br /

Playing with food: Maternal feeding style and perceptions of how preschoolers interact with toy foods in the home environment

Maternal feeding styles have been linked to dietary intake patterns in young children. Additionally, pretend play with toy foods provides a promising means of promoting development of healthy eating patterns in this age group and the potential of it to play a positive role in the home environment may, in part, be related to maternal interactions with the child during pretend play. The purpose of the present study was to explore maternal perceptions of pretend play with toy foods in the home environment relative to maternal feeding style. Specifically, our objectives were to employ a mixed-methods approach to 1) describe maternal observations of their preschool-aged children while engaged in pretend play with toy foods and related materials, 2) describe maternal perceptions as to how pretend play with toy foods relates to real life experiences of preschool-aged children, and 3) describe mothers’ observations and perceptions regarding pretend play with toy foods and relate these to maternal feeding style. Mothers of two to five-year-old children (n=25) were recruited via Facebook posts, online mother’s groups, recruitment flyers to childcare centers, and emails sent to a local database of mothers. Eligible mothers were invited to complete an online survey to collect sociodemographic data, classify the mothers as one of the four feeding styles, and gather their observations and perceptions regarding pretend play activities with toy food and related materials in the home via a series of open-ended questions. Patterns emerging from qualitative analysis of the mothers’ responses in combination with information on feeding style from the Caregiver’s Feeding Styles Questionnaire (CFSQ) suggest that mother’s interactions with their children and perceptions of the role of pretend play contrast by the dimensions of demandingness and responsiveness. Further exploration of the interplay between mothers and children in the pretend play environment will help to clarify how the role of pretend play with toy foods in promoting healthy eating may vary with maternal feeding styles

Gracefully Degrading Gathering in Dynamic Rings

Gracefully degrading algorithms [Biely \etal, TCS 2018] are designed to circumvent impossibility results in dynamic systems by adapting themselves to the dynamics. Indeed, such an algorithm solves a given problem under some dynamics and, moreover, guarantees that a weaker (but related) problem is solved under a higher dynamics under which the original problem is impossible to solve. The underlying intuition is to solve the problem whenever possible but to provide some kind of quality of service if the dynamics become (unpredictably) higher.In this paper, we apply for the first time this approach to robot networks. We focus on the fundamental problem of gathering a squad of autonomous robots on an unknown location of a dynamic ring. In this goal, we introduce a set of weaker variants of this problem. Motivated by a set of impossibility results related to the dynamics of the ring, we propose a gracefully degrading gathering algorithm

Distributed eventual leader election in the crash-recovery and general omission failure models.

102 p.Distributed applications are present in many aspects of everyday life. Banking, healthcare or transportation are examples of such applications. These applications are built on top of distributed systems. Roughly speaking, a distributed system is composed of a set of processes that collaborate among them to achieve a common goal. When building such systems, designers have to cope with several issues, such as different synchrony assumptions and failure occurrence. Distributed systems must ensure that the delivered service is trustworthy.Agreement problems compose a fundamental class of problems in distributed systems. All agreement problems follow the same pattern: all processes must agree on some common decision. Most of the agreement problems can be considered as a particular instance of the Consensus problem. Hence, they can be solved by reduction to consensus. However, a fundamental impossibility result, namely (FLP), states that in an asynchronous distributed system it is impossible to achieve consensus deterministically when at least one process may fail. A way to circumvent this obstacle is by using unreliable failure detectors. A failure detector allows to encapsulate synchrony assumptions of the system, providing (possibly incorrect) information about process failures. A particular failure detector, called Omega, has been shown to be the weakest failure detector for solving consensus with a majority of correct processes. Informally, Omega lies on providing an eventual leader election mechanism