1,721,187 research outputs found
A Microservices Architecture for Machine Learning Assisted Decision Support in a Real-Time Field Sensors Environment
Full text linkAgent-based Modelling of Stem Cells
No full textThe multiagent systems approach has become recognized as a useful approach for mod-
elling and simulating biological complex systems. In this chapter we provide an example of such an approach, which concerns the modelling and simulation of the Hematopoietic Stem Cell (HSC) system in adults. We are specifically interested in how local cell interactions give rise to well understood properties of systems of stem cells, such as the ability to maintain their own population and to maintain a population of fully differentiated functional cells.
There is a need to establish key cell mechanisms that can produce self-regulating behaviour of HSC systems using different theoretical techniques. It is our belief that modelling the behaviour of HSCs in the adult human body as an agent-based system is the most appropriate way of understanding these mechanisms and the consequent process of self-organisation.
In recent years there has been a growing debate about how stem cells behave in the human body; whether the fate of stem cells is pre-determined or stochastic, and whether the fate of cells relies on their internal state, or on extra-cellular micro-environmental factors. However, current experimental limitations mean that stem cells cannot be tracked in the adult human body. There is no way of “observing” micro-level behaviour. Models and simulations have a crucial role therefore in explaining the relationship of micro-behaviour to macro-behaviour and it now seems that the importance of computational modelling and simulation for understanding stem cells is beginning to be realised in many wet-labs. There have been several attempts to build formal models of these theories, so that predictions can be made about how and why stem cells behave, both individually or collectively.
In this chapter we propose an agent based model which describes at the same time the intracellular behaviour of the cell (i.e., intra-cellular networks) and the cellular level where all the systemic interactions are developed. This enables us to build a multi-level model
Self-Adaptation for Cyber-Physical Systems: A Systematic Literature Review
No full text© 2016 ACM. Context: Cyber-physical systems (CPS) seamlessly integrate computational and physical components. Adaptability, realized through feedback loops, is a key requirement to deal with uncertain operating conditions in CPS. Objective: We aim at assessing state-of-art approaches to handle self-adaptation in CPS at the architectural level. Method: We conducted a systematic literature review by searching four major scientific data bases, resulting in 1103 candidate studies and eventually retaining 42 primary studies included for data collection after applying inclusion and exclusion criteria. Results: The primary concerns of adaptation in CPS are performance, flexibility, and reliability. 64% of the studies apply adaptation at the application layer and 24% at the middleware layer. MAPE (Monitor-Analyze-Plan-Execute) is the dominant adaptation mechanism (60%), followed by agents and self-organization (both 29%). Remarkably, 36% of the studies combine different mechanisms to realize adaptation; 17% combine MAPE with agents. The dominating application domain is energy (24%). Conclusions: Our findings show that adaptation in CPS is a cross-layer concern, where solutions combine different adaptation mechanisms within and across layers. This raises challenges for future research both in the field of CPS and self-adaptation, including: how to map concerns to layers and adaptation mechanisms, how to coordinate adaptation mechanisms within and across layers, and how to ensure system-wide consistency of adaptation.status: Publishe
Patterns of Delegate MAS
Full text linkDelegate MAS has been proposed and investigated as an integrated coordination technique for so-called self-organising coordination-and-control applications. Delegate MAS consist of three types of light weight, ant-like agents that assist domain agents in their coordination tasks - the types are exploration, intention and feasibility ants. The technique is especially suitable for distributed applications in large-scale, dynamic systems. Literature shows that, for various application domains, solution approaches based on self-organisation have been proposed that have several similarities to delegate MAS, yet are not identical. In this paper, we specify three reusable solution patterns for coordination in distributed, large-scale, dynamic systems. To motivate the patterns, we first visit several solution approaches from various domains that bear resemblance with respect to coordination. We then identify common application characteristics as well as common technical challenges that underlie the approaches. We describe recurring solution techniques, and consolidate these in three solution patterns. The patterns are 'smart messages', 'delegate MAS', and 'delegate ant MAS' which rely on stigmergic ant agents. Identifying the patterns fosters reuse of particularly useful coordination techniques, and can serve as a catalyst for new or altered approaches. © 2009 IEEE.sponsorship: This research is partially funded by the Interuniversity Attraction Poles Programme Belgian State, Belgian Science Policy, and by the Research Fund K.U.Leuven. Danny Weyns is a post-doctoral researchers of the FWO-Vlaanderen. (Interuniversity Attraction Poles Programme Belgian State, Belgian Science Policy, FWO-Vlaanderen)status: Publishe
Pulverization in Cyber-Physical Systems: Engineering the Self-Organizing Logic Separated from Deployment
Full text linkEmerging cyber-physical systems, such as robot swarms, crowds of augmented people, and smart cities, require well-crafted self-organizing behavior to properly deal with dynamic environments and pervasive disturbances. However, the infrastructures providing networking and computing services to support these systems are becoming increasingly complex, layered and heterogeneous—consider the case of the edge–fog–cloud interplay. This typically hinders the application of self-organizing mechanisms and patterns, which are often designed to work on flat networks. To promote reuse of behavior and flexibility in infrastructure exploitation, we argue that self-organizing logic should be largely independent of the specific application deployment.
We show that this separation of concerns can be achieved through a proposed “pulverization approach”: the global system behavior of application services gets broken into smaller computational pieces that are continuously executed across the available hosts. This model can then be instantiated in the aggregate computing framework, whereby self-organizing behavior is specified compositionally. We showcase how the proposed approach enables expressing the application logic of a self-organizing cyber-physical system in a deployment-independent fashion, and simulate its deployment on multiple heterogeneous infrastructures that include cloud, edge, and LoRaWAN network elements
UNDERSEA:An Exemplar for Engineering Self-Adaptive Unmanned Underwater Vehicles
Full text linkRecent advances in embedded systems and underwater communications raised the autonomy levels in unmanned underwater vehicles (UUVs) from human-driven and scripted to adaptive and self-managing. UUVs can execute longer and more challenging missions, and include functionality that enables adaptation to unexpected oceanic or vehicle changes. As such, the simulated UUV exemplar UNDERSEA introduced in our paper facilitates the development, evaluation and comparison of self-adaptation solutions in a new and important application domain. UNDERSEA comes with predefined oceanic surveillance UUV missions, adaptation scenarios, and a reference controller implementation, all of which can easily be extended or replaced
Big data from the cloud to the edge: the aggregate computing solution
Full text linkWe advocate a novel concept of dependable intelligent edge systems (DIES) i.e., the edge systems ensuring a high degree of dependability (e.g., security, safety, and robustness) and autonomy because of their applications in critical domains. Building DIES entail a paradigm shift in architectures for acquiring, storing, and processing potentially large amounts of complex data: data management is placed at the edge between the data sources and local processing entities, with loose coupling to storage and processing services located in the cloud. As such, the literal definition of edge and intelligence is adopted, i.e., the ability to acquire and apply knowledge and skills is shifted towards the edge of the network, outside the cloud infrastructure. This paradigm shift offers flexibility, auto configuration, and auto diagnosis, but also introduces novel challenges. © 2019 ACM.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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