System-of-systems Research Articles

A novel hierarchical distributed framework for optimal reactive power dispatch based on a system of systems structure

Optimal reactive power dispatch is one of the major issues in operation of power systems which aims to minimize losses, voltage stability, voltage deviation, etc. through an optimal adjustment of control variables. Recently, some alterations have been involved in control procedures, management and scheduling of these systems due to the power systems restructure, electricity markets and smart grids. These changes are notable in methods used for optimal dispatch of reactive power as well. According to the hierarchical structure of the power grids, this paper presents a hierarchical distributed framework based on a System of Systems (SoS) concept. In this structure, every section of the grid is controlled by a smart agent. Agents are interconnected and exchange the required data via a telecommunication network. In this paper, the amounts of active and reactive power exchanged between agents are considered as boundary and common parameters. Our proposed method is implemented on the IEEE 118-bus network connected to 7 active power distribution networks. The results are compared to the ones obtained from a distributed method based on an Incident Command System (ICS) and a centralized control method. It turns out that the proposed method outperforms the other two competing methods.

System Importance Measures: Definitions and Application to System-of-Systems Analysis

Resilience is the ability to withstand and recover rapidly from disruptions. While this attribute has been the focus of research in several fields, in the case of system-of-systems (SoS), addressing resilience is particularly interesting and challenging. In this research, we present a new set of importance measures to aid in the design and analysis of resilient systems. Our system importance measures (SIMs) are inspired by the component importance measures in reliability engineering but are designed to address the distinguishing features of resilience, in particular, its non-binary nature. The SIMs facilitate rapid identification of vulnerable areas within the SoS. The SIM-based resilience design process allows designers to (1) determine the relative importance of different systems based on their impacts on overall resilience, and (2) improve overall resilience by drawing from design options that leverage system-specific characteristics. We demonstrate the calculation and use of the SIMs using a naval warfare SoS.

A novel two-stage distributed structure for reactive power control

In this paper, a new two-stage approach has been presented for the reactive power control of power systems. In the first stage, the transmission network is divided into several parts using a partitioning approach based on graph concept. In the second stage, a hierarchical distributed framework based on a System of Systems (SoS) concept has been proposed for optimal reactive power dispatch. In this structure, every section of the grid is controlled by a smart agent. Agents are interconnected and exchange the required data via a telecommunication network. In this paper, the amounts of active and reactive power exchanged between agents are considered as boundary and common parameters. Our proposed method is implemented on the IEEE 118-bus network connected to 7 active power distribution networks. The results are compared to the ones obtained from a distributed method based on an Incident Command System (ICS) and a centralized control method. It turns out that the proposed method outperforms the other two competing methods.

Towards an Uncertainty Framework for Product Service Systems of Systems

AbstractProduct Service Systems (PSS) are increasingly complex and collaborative. For instance, manufacturing companies, service providers, and other companies collaborate and jointly develop and operate a PSS (ex: smart grid), where its constituent elements are managed and operated independently. Managerial independence and operational independence are commonly considered key characteristics of a System of Systems (SoS). Hence, a collaborative PSS exhibits System of Systems (SoSs) characteristics. These systems have previously been introduced as Product Service Systems of Systems (PSSoSs). In this paper, we propose to identify relevant uncertainties in the PSSoS design process. For this purpose, we go beyond the PSSoS concept definition and propose a comprehensive framework for PSS and PSSoS characterization. Moreover, based on both a literature review and an industrial diagnosis, we identify PSSoSs-specific design uncertainties.

Simulating Systems-of-Systems Dynamic Architectures

Systems-of-Systems (SoS) combine heterogeneous, independent systems to offer complex functionalities for highly dynamic smart applications. Due to their critical nature, SoS should be reliable and work without interruption that could cause serious losses. SoS architectural design can facilitate the prediction of the impact of failures due to SoS behavior. However, existing approaches do not support such evaluation. The main contribution of this paper is to present Dynamic-SoS, an approach to predict, at design time, the SoS architectural behavior at runtime to evaluate whether the SoS can sustain their operation. Results of our multiple case studies reveal Dynamic-SoS is a promising approach that could contribute to the quality of SoS by reliably enabling prior assessment of their dynamic architecture.

Estimation of the Belonging Metric in a Hypothetical System-of-Systems

This paper presents application of an analytical technique that permits assessment of the strength and character of the belonging attribute in systems-of-systems (SoS). We further explore the quantification of this metric using a target system consisting of a migrating waterfowl flock. We used an agent-based model to simulate the formation and evolution of the SoS over time, and we assessed the aerodynamic benefit transferred among flock members in order to compute the belonging value. Results from model runs show that an evaluation of the overall SoS goal emerges organically from the transfer of drag reduction benefits among flock members; that benefits accrue to each individual member system as well as to the collective; and that the degree to which belonging benefits the whole varies depending on initial choices made regarding the architecture of the SoS. As an exploration of the underlying system characteristics, we propose that these results can inform the design of engineered systems.

A System Dynamics and Scenarios Framework for Architecting Product Design Goals for Changeability

The design of changeable product architecture requires modeling the dynamic interaction between products and the sociotechnical sphere, in order to understand where changeability is needed. For example, a government approval of airport expansions will impact airline operations, and the design priorities of new airliners. The purpose of this paper is to develop an approach to determine design goals for a new product architecture in system of systems (SoS). These goals become dynamic, once linked to their underlying societal changes. The characteristic of the approach is to integrate system dynamics (SD) and scenario planning; thus, SD captures quantitative aspects of societal and product function dynamics, while scenarios provide a narrative explicating parameter choices, assumptions, and implications. In this paper, SD models include business and societal aspects to evaluate long-term profitability. Goal prioritization for a new product is obtained in the form of importance weights via global sensitivity analysis; these weights are highly dependent on external functions and risk attitude, and vary in time. A toy case study deals with modeling the household freezer's past evolution in an SoS to find evolving design priorities. The result is a positive evaluation of the method, using a recent Design for Changeability framework.

Research on Construction of Intelligent Operational Simulation Test Environment

With the development of simulation technologies, simulation test has become an important means of weapon equipment demonstration, finalization and operational test and evaluation, but the simulation test system built for the performance evaluation cannot meet the requirements of system of systems (SoS) operational test and evaluation. This paper analyzes the requirements of the operational simulation test for the intelligent simulation test system and puts forward an intelligent simulation framework of the complex simulation test system and its main elements, which realizes the simulation of the operational activities with uncertain confrontation process and can support the demonstration, construction and evaluation of the weapon equipment system. The research results have been applied to the construction of a certain simulation system and provided support for the test and evaluation of equipment SoS tests.

A Context-Aware Augmentative and Alternative Communication System for School Children With Intellectual Disabilities

Children with intellectual disabilities (ID), especially those who fail to communicate with normal speech, suffer from various limitations in their social functioning. They often rely on alternate methods to supplement or replace verbal communication. There is a rapidly growing number of augmentative and alternative communication (AAC) mobile applications available over recent years. However, the operation of these applications remains a challenge for users with ID since they may not have the sufficient cognitive proficiency to cope with the application interface. In this paper, we present the design, implementation, and evaluation of a Bluetooth low energy (BLE) based context-aware AAC system. Our system facilitates daily communication for nonverbal school children with moderate ID in order to address their learning and communication needs. We have piloted and evaluated our system at a special education school in Hong Kong. Our technical contribution is twofold. First, we introduce BLE technology to the AAC field and show its effectiveness on users with ID. Second, by converting conventionally standalone AAC software into a service system and empowering it with Internet of Things functionality, we open up many new opportunities brought by the system-of-systems (SoS) paradigm for the intellectually disabled population.

DEVELOPMENT OF UAV SOS FLIGHT COMBAT RECONNAISSANCE MISSION PROGRAM

System of systems (SoS) conception for dynamic objects group have been become a very important direction in various areas on science and industry, including military. SoS is consisted of components which solve one task and on the whole jointing own properties and possibilities these components creat the complex system with new qualities. SoS is such system which during various operations combines and joints itself a synergetics of comands, control functions, network and feedback information change. In given paper, development of the combat task program of Unmanned Aerial Vehicles System of Systems offered version has been presented. Usually, the land control center manage UAVs by using of radio wireless. But it has shortcomings: 1) a radio wireless can be destroy, and in the best case UAV does not emplement task and self returns base; 2) an enemy taps the radio wireless and carry out UAVs control. The creation of SoS on the basis of UAVs eliminates these flaws. In accordance with written in memory software program, UAVs SoS is self-controlled by infra-red (IR) wireless using “feedback” principle and it implement combat task independently. If some of UAVs loss IR-wireless then it (or they) return land control center independently. If some of UAVs is destroyed under enemy fire then other UAVs continue to implement a combat task. The Hamilton equations of motion of the given system has been obtained. The IR wireless between UAVs, radio wireless between UAVs and land control post, and UAVs flight control conditions have been offered. It is shown that Unmanned Aerial Vehicle System-of-System complex can implement in various military reconnaissance tasks.

Model and Data-Driven System Portfolio Selection Based on Value and Risk

System portfolio selection is a kind of tradeoff analysis and decision-making on multiple systems as a whole to fulfill the overall performance on the perspective of System of Systems (SoS). To avoid the subjectivity of traditional expert experience-dependent models, a model and data-driven approach is proposed to make an advance on the system portfolio selection. Two criteria of value and risk are used to indicate the quality of system portfolios. A capability gap model is employed to determine the value of system portfolios, with the weight information determined by correlation analysis. Then, the risk is represented by the remaining useful life (RUL), which is predicted by analyzing time series of system operational data. Next, based on the value and risk, an optimization model is proposed. Finally, a case with 100 candidate systems is studied under the scenario of anti-missile. By utilizing the Non-dominated Sorting Differential Evolution (NSDE) algorithm, a Pareto set with 200 individuals is obtained. Some characters of the Pareto set are analyzed by discussing the frequency of being selected and the association rules. Through the conclusion of the whole procedures, it can be proved that the proposed model and data-driven approach is feasible and effective for system portfolio selection.

Towards a knowledge base to support global change policy goals

ABSTRACTIn 2015, it was adopted the 2030 Agenda for Sustainable Development to end poverty, protect the planet and ensure that all people enjoy peace and prosperity. The year after, 17 Sustainable Development Goals (SDGs) officially came into force. In 2015, GEO (Group on Earth Observation) declared to support the implementation of SDGs. The GEO Global Earth Observation System of Systems (GEOSS) required a change of paradigm, moving from a data-centric approach to a more knowledge-driven one. To this end, the GEO System-of-Systems (SoS) framework may refer to the well-known Data-Information-Knowledge-Wisdom (DIKW) paradigm. In the context of an Earth Observation (EO) SoS, a set of main elements are recognized as connecting links for generating knowledge from EO and non-EO data – e.g. social and economic datasets. These elements are: Essential Variables (EVs), Indicators and Indexes, Goals and Targets. Their generation and use requires the development of a SoS KB whose management process has evolved the GEOSS Software Ecosystem into a GEOSS Social Ecosystem. This includes: collect, formalize, publish, access, use, and update knowledge. ConnectinGEO project analysed the knowledge necessary to recognize, formalize, access, and use EVs. The analysis recognized GEOSS gaps providing recommendations on supporting global decision-making within and across different domains.

Net Shape Extrusion of Titanium Bars through Coupled two Part Preform Manufacturing Process: System of Systems Approach—Part II

The first part of this paper explored the identification of various methodological challenges which have to be addressed when designing complex multi-system integration associated with titanium metalworking and manufacture, while in this second part of the paper, we explore the evolution of System of Systems (SoS) design and development of complex multi-system integration. Theory of Inventive Problem Solving (TRIZ) is employed to address identified system incongruity. The utilization of the SoS design approach coupled with the TRIZ innovation technique proved effective at addressing the system constraints for the titanium manufacturing supply chain. The utilization of the two-part process prescribed by the SoS design approach proved effective at addressing requirements and broadly stated industry needs. Through this unique system, design net-shaped structural beam from common aerospace grade titanium (Ti-6Al-4V) was successfully manufactured.

Architecting federations of systems: A framework for capturing synergy

AbstractThis paper defines Federations of Systems, introduces a tailored architecting framework, and demonstrates it in a satellite design case study. While certainly not being new concepts in the literature, federations are a class of Systems of Systems (SoS) that have not been extensively explored due to the scarcity of applied examples and still few practitioners facing their specific design challenges. This is expected to change with the advent of the Internet of Things, Machine to Machine applications, collaborative consumption, and Federated Satellite Systems. It has become henceforth necessary to develop approaches in design and architecting capable of addressing such interconnected sets of systems.Federations are SoS characterized by the absence of global goals and stakeholders, and cooperation enabled only on an opportunistic basis. Systems engage in federations when the perceived benefit exceeds the costs of the necessary interfaces. The proposed framework quantifies the upper limits to the net benefits of cooperation between systems through the concept of synergy. Using synergy as a heuristic to navigate federated design spaces, the framework predicts the appearance and evolution of federations.The demonstration of the framework in a six‐satellite federation shows that advantages of federating emerge with the collaboration between just two systems. Interface costs, architectural cost preferences, and network topology drive the achievable benefits. Specifically, when considering communication architectures under 80 MUSD for satellite systems, federating is advantageous when the interface lifecycle costs are below 15 MUSD. This demonstration case exemplifies how federating can assist systems in achieving design points that dominate the solutions of their local tradespace.

System of Systems Approach for Maintaining Wastewater System

AbstractThis study demonstrates that modeling a wastewater system as a system of systems (SoS) rather than a monolithic system constitutes a useful methodological approach to dealing with the compl...

A Model-Based Engineering Methodology and Architecture for Resilience in Systems-of-Systems: A Case of Water Supply Resilience to Flooding

There is a clear and evident requirement for a conscious effort to be made towards a resilient water system-of-systems (SoS) within the UK, in terms of both supply and flooding. The impact of flooding goes beyond the immediately obvious socio-aspects of disruption, cascading and affecting a wide range of connected systems. The issues caused by flooding need to be treated in a fashion which adopts an SoS approach to evaluate the risks associated with interconnected systems and to assess resilience against flooding from various perspectives. Changes in climate result in deviations in frequency and intensity of precipitation; variations in annual patterns make planning and management for resilience more challenging. This article presents a verified model-based system engineering methodology for decision-makers in the water sector to holistically, and systematically implement resilience within the water context, specifically focusing on effects of flooding on water supply. A novel resilience viewpoint has been created which is solely focused on the resilience aspects of architecture that is presented within this paper. Systems architecture modelling forms the basis of the methodology and includes an innovative resilience viewpoint to help evaluate current SoS resilience, and to design for future resilient states. Architecting for resilience, and subsequently simulating designs, is seen as the solution to successfully ensuring system performance does not suffer, and systems continue to function at the desired levels of operability. The case study presented within this paper demonstrates the application of the SoS resilience methodology on water supply networks in times of flooding, highlighting how such a methodology can be used for approaching resilience in the water sector from an SoS perspective. The methodology highlights where resilience improvements are necessary and also provides a process where architecture solutions can be proposed and tested.

Resilience assessment as a foundation for systems-of-systems safety evaluation: Application to an economic infrastructure

In this paper, the authors propose two complementary approaches in an attempt to contribute to systems-of-systems (SoS) safety evaluation through resilience assessment. The first approach is a risk monitoring design, it is conceived to monitor, evaluate and analyze risks that represent destabilizations’ catalyzers. The second one is a structural analysis that begins with the estimation of criticality and frailty levels which leads to the calculation of failure impact and susceptibility measures of a component system on/to the SoS performance and process continuity. The combination of these approaches helps to assess SoS resilience through building a futurist, quantitative and anticipative perspective to evaluate the potential risks, their influences and impacts on SoS structure. Accordingly, this embraces a step towards safety forecast, evaluation and enhancement. A case study of a real-based economic infrastructure of a geographic area in France approached as a SoS model, is provided to experiment the proposition. The outcome of the presented approach’s application shows that: (1) the use of the risk’s monitoring dashboard helps to qualitatively illustrate risks striking the SoS or could possibly affect it in the future; (2) the structural analysis evaluates the impact of a component system’s failure on the overall performance and efficiency of the SoS embracing it and vice versa; (3) the proposed approach could be used for anticipative and preventive reasons.

A framework with revised rough-DEMATEL to capture and evaluate requirements for smart industrial product-service system of systems

Smart industrial product-service system of systems (SiP-S3) is a new extension of industrial PSS via smart technology and SoS (system of systems) engineering. A framework with revised rough-DEMATEL method is proposed to capture and evaluate requirements for SiP-S3. From the various interactions in value stream mapping of SiP-S3, business, functional and non-functional requirements can be captured and converged into SiP-S3 requirements. Due to the interrelation between requirements of SiP-S3 and uncertainty of expert judgments, rough-DEMATEL is adopted but is revised in two aspects. Generally, SiP-S3 requirement items are plentiful, a set of programming code for rough set approximation is firstly given to reduce manual calculation burden. Moreover, compared to multiple operators of modified-CFCS (converting fuzzy values into crisp scores) plus SVL (single vector-length), a feasible and simpler operator of AVL (average vector-length) on rough-prominence and rough-relation is firstly devised to prioritise requirements. As such, roughness can be remained till at the end of calculation procedure to avoid uncertain assessment information loss. Surface mount technology (SMT) is not trivial in electronic manufacturing service industry, an illustrative case study of SMTE-S3 (SMT equipment-service system of systems) is demonstrated to verify feasibility and potential of proposal methodological framework.

A motifs-based Maximum Entropy Markov Model for realtime reliability prediction in System of Systems

System of Systems (SoS) based on service composition is considered as an effective way to build large-scale complex software systems. It regards the system as a service and integrates multiple component systems into a new system. The performance of the component system may fluctuate at any time because of the complex and changeable running state and external environment of the component system, which will affect the running of the SoS. The online reliability prediction technology is used to predict the reliability of the component system of an SoS in the near future. It aims to find errors and correct them in time so as to ensure that the SoS can run continuously and smoothly. To tackle the reliability prediction problem of component system in a dynamic and uncertain environment, the paper integrates Maximum Entropy Markov Model (MEMM) with time series motifs to achieve a new prediction model (m_MEMM), which is referred to as motifs-based MEMM. Extensive experiments are conducted to demonstrate the effectiveness and accuracy of the proposed approach.

An Approach to Systems-of-Systems Structural Analysis through Interoperability Assessment: Application on Moroccan Case

In this paper, we propose an indicator to systems-of-systems (SoS) structural analysis through dependencies evaluation which is based on interoperability and exchange inefficiency assessments, with dependencies representing links between component systems within the SoS. Interoperability is a quality that can be viewed from various perspectives. Therefore, we propose an illustrative classification for interoperability that embraces: barriers, scopes and levels. Our study involves a set of metrics to assess each interdependency’s interoperability barriers within the SoS through interoperability levels. Two different case studies, from the Moroccan economic infrastructure, are presented to apply the proposed approach. Results are cross-compared and evaluated.