Consensus Computation in Unreliable Networks: A System Theoretic Approach

This work addresses the problem of ensuring trustworthy computation in a linear consensus network. A solution to this problem is relevant for several tasks in multi-agent systems including motion coordination, clock synchronization, and cooperative estimation. In a linear consensus network, we allow for the presence of misbehaving agents, whose behavior deviate from the nominal consensus evolution. We model misbehaviors as unknown and unmeasurable inputs affecting the network, and we cast the misbehavior detection and identification problem into an unknown-input system theoretic framework. We consider two extreme cases of misbehaving agents, namely faulty (non-colluding) and malicious (Byzantine) agents. First, we characterize the set of inputs that allow misbehaving agents to affect the consensus network while remaining undetected and/or unidentified from certain observing agents. Second, we provide worst-case bounds for the number of concurrent faulty or malicious agents that can be detected and identified. Precisely, the consensus network needs to be 2k+1 (resp. k+1) connected for k malicious (resp. faulty) agents to be generically detectable and identifiable by every well behaving agent. Third, we quantify the effect of undetectable inputs on the final consensus value. Fourth, we design three algorithms to detect and identify misbehaving agents. The first and the second algorithm apply fault detection techniques, and affords complete detection and identification if global knowledge of the network is available to each agent, at a high computational cost. The third algorithm is designed to exploit the presence in the network of weakly interconnected subparts, and provides local detection and identification of misbehaving agents whose behavior deviates more than a threshold, which is quantified in terms of the interconnection structure

Products of Generalized Stochastic Sarymsakov Matrices

In the set of stochastic, indecomposable, aperiodic (SIA) matrices, the class of stochastic Sarymsakov matrices is the largest known subset (i) that is closed under matrix multiplication and (ii) the infinitely long left-product of the elements from a compact subset converges to a rank-one matrix. In this paper, we show that a larger subset with these two properties can be derived by generalizing the standard definition for Sarymsakov matrices. The generalization is achieved either by introducing an "SIA index", whose value is one for Sarymsakov matrices, and then looking at those stochastic matrices with larger SIA indices, or by considering matrices that are not even SIA. Besides constructing a larger set, we give sufficient conditions for generalized Sarymsakov matrices so that their products converge to rank-one matrices. The new insight gained through studying generalized Sarymsakov matrices and their products has led to a new understanding of the existing results on consensus algorithms and will be helpful for the design of network coordination algorithms

PENERAPAN PROTOKOL PUBLISH / SUBSCRIBE MESSAGING SYSTEM PADA SISTEM WIRELESS BUILDING NETWORK BERBASIS NRF24L01

Wireless sensor network is a common method used in the design of shared resource interconnection infrastructure at a location point to provide optimal performance. The main factor in the design of a wireless sensor network (WSN) communication protocol in the form of coordination optimization efforts between nodes, one of the effective methods that can be made to achieve such conditions is the provision of nodes using the publish / subscribe messaging system protocol. This research discusses the implementation of publish / subscribe messaging system protocol on wireless building network system based on NRF2L01. Discussions include simulation, design, implementation, application testing and system performance both on a work-to-work and performance-by-node performance. The results showed the system was able to monitor all information and control equipment from a building through a web interface making it easier for officers to maintain and supervise a building, then to test the performance of nodes with a fixed data packet size of 32 bytes, the delay value for each node is less than 1 second, then for the minimum throughput 250 kbps data rate obtained at 5.9 Kbps and the maximum throughput obtained at 72 Kbps and for packet loss of at least 0.59% while the maximum packet loss of 13.23% and the standard deviation value of delay, throughput and packet loss are smaller than the average value, the data is not very varied (stable)

Interplant coordination, supply chain integration, and operational performance of a plant in a manufacturing network: a mediation analysis

Purpose The purpose of this paper is to investigate the relationships at the level of plant in a manufacturing network, labelled as networked plant in the paper, between inter-plant coordination and operational performance, supply chain integration (SCI) and operational performance and inter-plant coordination and SCI. Design/methodology/approach This paper is developed based on the data obtained from the sixth version of International Manufacturing Strategy Survey (IMSS VI). Specifically, this paper uses a subset of the IMSS VI data set from the 606 plants that identified themselves as one of the plants in a manufacturing network. Findings This paper finds that external integration is significantly related to operational performance of networked plant, whereas internal integration is not. As an enabler for external integration, the influence of internal integration on operational performance of networked plant is mediated by external integration. This paper also provides evidence to the purported positive impact of internal integration on inter-plant coordination, as well as the positive impact of inter-plant coordination on external integration. It further suggests that inter-plant coordination can influence operational performance of networked plant through external integration and also mediate the relationship from internal integration to performance through external integration. Originality/value This paper contributes to the SCI literature and extends the understanding of the impact of SCI on the operational performance by selecting networked plant as a unit of analysis. Besides, this paper distinguishes inter-plant coordination from SCI and investigates the relationship between inter-plant coordination, SCI, and operational performance for the first time

The influence of IIoT on manufacturing network coordination

Purpose: The coordination of a manufacturing network is a challenging task and may be contingent upon the manufacturing environment. The purpose of this paper is to analyse how industrial Internet of Things (IIoT) and manufacturing network coordination relate. Design/methodology/approach: Based on a single case study, the paper at hand provides insights on IIoT enablers and the relationship to manufacturing coordination mechanism. The data sample is based on 15 group interviews with overall eight employees from headquarters and business units. Findings: The derived results show that the IIoT enablers (digital technologies, connectivity, data, capabilities and management) are highly related to the manufacturing network coordination mechanism. The results indicate that IIoT initiatives and manufacturing network coordination should be designed to support each other. Originality/value: The implementation if IIoT initiatives is often analysed in isolation without considering the manufacturing network and more specifically the manufacturing network coordination mechanism. The results highlight how the implementation of IIoT initiatives may act as trigger to adapt formal manufacturing network coordination mechanism

Social network analysis in operations and supply chain management: A review and revised research agenda

Purpose Social network analysis (SNA) seeks to manage the connections between entities through investigating and understanding behaviours and relationships. This study demonstrates the increasing relevance of social network approaches to solving contemporary and looming operations management (OM) and supply chain management (SCM) problems; including the coordination operations challenges raised by increased connectivity. Design/methodology/approach The systematic literature review approach adopted here examines 63 papers in OM and SCM published between 2000 and 2019. To-date OM reviews on SNA have focussed on discussing archetypal supply chains, what differentiates this study is the focus on how value was created in other forms of chains and operations. Findings This study reveals that current SNA adoption in OM is dominated by a manufacturing style focus on linear, sequential value creation, with a resulting focus only on sequential interdependence. SNA studies on reciprocally co-ordinated value creation (e.g. many service and network operations) are shown to have been neglected and are linked to a new agenda on contemporary management issues. Research limitations/implications Beyond encouraging the use of SNA, this study seeks to re-orient SNA approaches towards how contemporary services and networks create value. Originality/value Through adopting a unique combination of approaches and frameworks, this study challenges extant work to offer a substantially revised agenda for SNA use in Operations and Supply Chain Management

Coordinating service composition

The fundamental paradigm shift from traditional value chains to agile service value networks implies new economic and organizational challenges. As coordination mechanisms, auctions have proven to perform quite well in situations where intangible and heterogeneous goods are traded. Nevertheless traditional approaches in the area of multiattribute combinatorial auctions are not quite suitable to enable the trade of composite services. A flawless service execution and therefore the requester\u27s valuation highly depends on the accurate sequence of the functional parts of the composition, meaning that in contrary to service bundles, composite services only generate value through a valid order of their components. We present an abstract model as a formalization of a service value network. The model comprehends a graph-based mechanism design to allocate multiattribute service offers within the network, to impose penalties for non-performance and to determine prices for complex services. The mechanism and the bidding language support various types of QoS attributes and their (semantic) aggregation. We analytically show that this variant is incentive compatible with respect to all dimensions of the service offer (quality and price)

Dissonance and diplomacy: coordination of conflicting values in urban co-design

This article seeks to contribute to the ongoing discussion on values in co-design processes, by introducing concepts from the emerging field of valuation studies. Using the work of David Stark and Ignacio Far\uedas as an entry point to this perspective, it shows how co-design can be understood as a collective process of finding negotiated settlements among conflicting accounts of value, through practices of coordination. This idea is illustrated by a case in which co-design is mobilised as a tool for developing and governing ‘active frontages’ in a regenerating district in Gothenburg, Sweden. The article shows how the valuation studies perspective relates to, and in part differs from, other approaches to collaborative and participatory design. While sharing some of the intuitions of both agonism- and actor-network theory-informed approaches, its front-staging of practices and principles of valuation does nevertheless provide an alternative perspective on co-design. The valuation approach depicts co-design processes as a negotiation-based search for settlements, which suspends rather than solves value conflicts. Thus, co-design may be construed as a form of diplomacy, which operates within certain political limits of designerly peacemaking