Constituent Systems Research Articles

Resilience in emerging complex intelligent systems: A case study of search and rescue

AbstractAs artificial intelligence (AI) is becoming part of complex systems and critical infrastructures, perspectives on resilience may need to be revisited. This paper focuses on the challenges and approaches in engineering design for achieving resilience in complex and increasingly intelligent systems (CoIS). Building on a case study of a system situated in the context of search and rescue (SAR) operations at sea as well as scenarios of SAR operations supported by AI solutions, it outlines challenges for organisational and engineering design in contexts where flexibility, adaptability, and high reliability are important. The findings point at resilience as a system property, made up of the constituent systems, their interaction and coordination in a system‐of‐systems framework. AI and autonomy in CoIS represent potentially a double‐edged sword; while AI and autonomy contribute to system capabilities and resilience, they can also introduce limitations in terms of, for instance, confined operational envelopes. Achieving resilience in CoIS thus requires a holistic approach that considers constituent systems as well as their interplay, organisational factors, and the judicious balance of AI and human‐based solutions.

Enthalpies of Mixing in Al−Ce−Co Liquid Alloys

AbstractThe enthalpies of mixing in liquid alloys of the ternary Al−Ce−Co system were determined along four sections (with a constant mole fraction ratio xCe/xCo=0.77/0.23 and xCe/xCo=0.35/0.65 up to xAl=0.2 at 1700 K; with xAl/xCo=0.76/0.24 up to xCe=0.3 and xAl/xCe=0.30/0.70 up to xCo=0.23 at 1823 K) via isoperibolic calorimetry. The enthalpies of mixing in the liquid Al−Ce−Co alloys are large exothermic values. A comparison of the experimentally obtained results for the enthalpies of mixing of liquid alloys and those calculated by the regular Redlich‐Kister‐Muggianu model, taking into account only the data for binary constituent systems, indicates the specific exothermic ‘ternary’ contribution to the energy of formation of Al−Ce−Co ternary alloys. Data on the partial enthalpy of mixing of cobalt at infinite dilution indicate the involvement of cerium 4 f‐electron in the process of alloy formation.

Thin-film flexible zinc hybrid electrochemical device integrating three chemical pathways

Combining the strengths of supercapacitors and batteries onto a single device is a holy grail which would enable many applications to be covered by the same device. Here, we firstly develop a hybrid electrochemical device integrating chemical pathways of a zinc hybrid supercapacitor, an electrolytic MnO2-zinc battery and a zinc-iodide battery. The integrated hybrid devices demonstrate a capacity of 453.1 mAh/g (corresponding to an energy of 400.4 Wh/kg, based on weight of activated carbon) and a capacitance of 720.7 F/g at output power of 220.3 W/kg. The three different chemical pathways symbiotically work together, achieving improved cycling performance, shelf-life and Coulombic Efficiencies compared to any of its constituent systems individually.

Hyundai's Modular MBSE Approach to ‘Purpose Built Vehicle’ Architecture Development

AbstractThis paper discusses an ongoing effort at Hyundai to develop a model‐based systems engineering (MBSE) methodology for cross‐domain vehicle architecture development that is practical at the enterprise level. Our approach follows a modular modeling process that complements MBSE. In the age of smart mobility, automobile systems are indeed interdependent elements of a system of systems (SoS). Connectedness favors numerous mobility features that emerge due to the interfaces among these constituent systems. Managing emergent product line variations, changing consumer demands coupled with faster market response require manufacturers to modularize their architecture development processes. This can help scale MBSE across vehicle programs. This study proposes a modular system architecture approach for developing Hyundai's purpose‐built vehicle (PBV) concept that maintains a link to the legacy vehicle breakdown structures already in use. Using the Arcadia method, the ‘to‐be’ developed electric vehicle is expressed as a hierarchical functional partitioning of the subsystem modules. A physical architecture is defined as a solution to the functional partitioning based on an existing vehicle breakdown in a combined ‘top‐down/bottom‐up’ workflow thus capturing a realistic system decomposition. In the SoS hierarchy, the PBV is at the top level and is partitioned into multiple levels of nested subsystem architectures owned and developed by designated module teams in a distributed modeling environment. Results of the preliminary architecture modularization effort indicate significant potential for benefits over classical architecture modeling such as iterative knowledge capture, enhanced reusability across projects, products and programs, and distributed vehicle performance development across the extended MBSE enterprise, which includes the tier 1/2 suppliers.

Modeling swarm mission with COTS characterization: a series of return on experience

AbstractSystem design in defense systems is a competitive field, in which economical viability relies on a sequence of architectural decisions, aiming at quality, resource and time (Q,R,T) compromises. We observe that low‐cost unmanned ground vehicles (UGV) and drones appear as new threats on current battlefield. To face these new threats, Direction Générale de l'Armement (DGA) have organized challenges around robotization of battlefield, to design future employment doctrines and help technologies to reach maturity in a reasonable time. This article exposes a NATO Architecture Framework (NAF) 3.1‐based workflow that includes return of experience form the field over yearly iterations of such challenges. The capabilities depicted are requirements to match, constituent systems are based on Components‐Off‐The‐Shelf (COTS) answering to both edition of the challenge. This article details how manually re‐injecting feedback from field back to the system model failed to ensure the next iterations of the challenge. Our works propose conclusions on formulation of the “engineering leakage problem” and how resolution of this problem is NP‐Hard and should be addressed using optimization.

Evaluating the Scalability and Combinatorial Effectiveness of Design‐for‐Resilience Heuristics

AbstractThis study investigates the scalability of biologically inspired design‐for‐resilience heuristics in System of Systems (SoS) of varying sizes, simulating SoS with ten, twenty, and thirty constituent systems. We build upon previous research that identified thirteen design heuristics for SoS resilience based on Ecological Network Analysis (a subset of graph theory). We both extend their application to larger network sizes and combine them to enhance efficiency. Our analysis validates the application of design heuristics for random networks to evaluate the effectiveness of individual and combined design heuristics in network resilience compared to random network modifications. The outcomes provide insights into the scalability and efficiency of these heuristics, revealing the potential for systematic SoS design and resilience improvement. Key contributions of this research include the validation of the scalability of bio‐inspired resilience metrics and the testing of nine new combined design heuristics for SoS. These contributions provide a tool for decision‐makers seeking to select resilient SoS architectures. The findings also pave the way for future research into broader applications beyond ecological networks and further exploration of the relationship between ecological robustness and resilience.

Coupling Independent Solid Mechanics-Based Systems in a System-of-Systems Modeling Framework

Modularity is essential for ensuring the efficient execution of system-of-systems (SoS) frameworks, demanding the managerial and operational independence of constituent systems. This study explores the feasibility of enforcing displacement compatibility between two interconnected, independent solid mechanics finite element models with a contact interface within an SoS. This work developed an approach that ensures operational independence by delaying displacement compatibility in one of the systems. The lagged system provides a trial displacement input to the leading system, which determines the displacement discrepancy between both systems. This error is used to calculate an equivalent pressure that enforces displacement compatibility between the models. The method was verified by modeling two specimens with a frictionless contact interface and comparing the results against a continuous model assuming a perfect bond between the specimens. Lastly, the method was implemented within an SoS for space habitats and proved effective in ensuring matching displacements at the contact surface between two interacting structural layers. The proposed approach preserves the modularity of coupled systems, avoiding complex iterative procedures and transferring mass and stiffness information between systems. Moreover, it allows the coupled models to be developed in independent coordinate systems, as they only pass scalar, coordinate-independent parameters through the input–output ports.

A New Horizon for Healthcare Delivery: A System of Systems Perspective and Governing Proposition

AbstractThe healthcare system is grappling with inherent challenges, functioning akin to a fragmented cottage‐like industry, leading to significant cost implications and compromised care quality. This paper employs a systematic approach to scrutinize the Healthcare Delivery System (HDS) comprehensively, categorizing it as a Collaborative System of Systems (SoS), where multiple independent systems operate collectively, maintaining individual autonomy. Through a detailed examination, we identify the Collaborative SoS nature of the current healthcare system as the primary cause of its fragmentation. We address a gap in the current literature on the characteristics of SoS, focusing on the often‐overlooked aspect of dependence and exploring why constituent systems collaborate to achieve common objectives. Then, we propose a hybrid SoS model where an external governing entity at the national level assumes the authority to determine objectives and drivers for the healthcare SoS. We contend that effective SoS governance is indispensable for addressing systemic issues, providing necessary coordination, allocating resources, establishing policies, fostering sustainable change, and ensuring a well‐organized and efficient healthcare system.

A CORPUS-BASED STUDY OF SIMPLE PAST TENSE ERRORS IN MALAYSIAN LEARNERS’ ENGLISH WRITING

In mastering the English language, learners need to be able to comply with its grammatical rules. Most previous corpus-based studies about learners’ grammar errors have examined the non-Malaysian context. Therefore, the overarching aim of this study is to investigate simple past tense errors in Malaysian English as a Second Language (ESL) secondary school learners’ writing. Employing a corpus-based error analysis approach, it specifically intends to identify the types of simple past tense errors in Malaysian ESL secondary school learners’ writing and the frequency of simple past tense errors in Malaysian ESL secondary school learners’ writing. To this end, the English of Malaysian School Students (EMAS) corpus, in particular the sub-corpus of Malaysian learners’ narrative essays was analysed based on two main frameworks. The Error Analysis Framework was adapted for the error analysis procedure, while the Surface Strategy Taxonomy Framework was used for the classification of types of errors. Online corpus tools such as Part-Of-Speech (POS) the Constituent Likelihood Automatic Word-Tagging System (CLAWS) and Antconc version 3.5.8 were employed as the instruments of the study. The findings of the study showed that there are three types of simple past tense errors in the learners’ writing, namely Error of Omission, Error of Addition and Error of Misformation. Misformation is the most popular type of simple past tense error committed by the learners. The findings of the study would be useful for the Malaysian context of ESL learners’ curriculum design and pedagogy.

Interactions between natural resources and false democracy?

A substantial political economy literature argues that it does not support a positive relationship between natural resources and autocracy. This study introduces a theoretical model and empirically estimates the relationship between natural resource endowment, democratic electoral systems, and electoral fraud. Electoral fraud and the introduction of a democratic electoral system have opposite positive and negative implications for democratization. This study examines the possibility that the opposite conditions are going on at the same time. In previous studies, indicators of Polity, a variable of institutional quality, have been used to identify not only the relationship between natural resources and institutions but also the relationship between natural resources and democratization.Our work uses data from around the world since 1800 to examine whether the executive is autocratic but would introduce proportional representation, a more democratic electoral system than the constituency system, to gain international support. It also examines whether a false democracy is compatible with the separation of powers gained by the executive branch respecting the judiciary and the legislature. The results of the analysis show that natural resources can be used to finance the consolidation of dictatorships and promote false democracy. The higher the natural resource endowment, the more money that can be obtained from natural resources can be used by politicians for political funding. Politicians introduce democratic political institutions and acquire political power through electoral fraud. At first glance, this is not a dictatorship but essentially suggests that political authorities are not replaced, giving rise to a more robust dictatorship. These theoretical and empirical analyses show that the degree of respect of the executive branch for the judiciary and legislature, the existence of a system of unconstitutional review, and political regimes such as military regimes and authoritarianism affect electoral fraud and false democracy by analyzing by region, degree of inequality and by income.

Aggregate Boid behavior to aid in artificial autopoietic organization

Analyzing carbon-based life on earth can lead to biased inferences on the nature of life as might exist in elsewhere in the universe in alternative forms, therefore, scientists have looked into either abstracting life into constituent systems it is comprised of, or logics of life, or lists of essential criteria, or essential dynamic patterning that characterizes the living. A system-level characterization that is and referred to as a general pattern of minimal life is autopoiesis (Varela et al., 1974) including production, maintenance and replacement of required constituents for setting up and maintaining an internal environment with self/other separation that regulates and is constitutive of processes that produce the environment and components for processes that comprise this ongoing activity of self-production in ‘recursively’, i.e., in a manner that allows the organizational pattern to continually reconstitute the conditions, components and processes required for its own perpetuation. This seminal concept of an autopoiesis is instantiated in life as we know it, but might also be instantiated in different media and in unforeseen ways. Other researchers have argued life is more than autopoiesis and that it is a co-emergent property of autopoiesis and cognition. Life produces many emergent properties such as synchronization and patterns as seen in flocks and herds of different animal species. The mechanics of this synchrony displayed in flocks and herd animals has been extracted by Craig Reynolds into a generative model referred to as “Boids”. With these concepts in mind, we address the following research question: How can the synchronous maneuvers and aggregate behavior of Boids contribute to constitutive subsystems in realizing an autopoietic system? Can such a system exhibit minimal cognition? This work attempts to answer these questions with a bottom-up approach to constructing an artificial life system. We exhibit a computational model of autopoiesis and a minimal level of cognition in the sense of M. Bitbol and P. Luigi Luisi, whereby an autopoietic entity engages in active assimilation of external components as part of its activity of self-production.

A Novel Method for the Seismic Resilience Assessment of Railway Stations Based on Quantitative Indices

ABSTRACT A novel method for assessing the seismic resilience of railway stations is introduced. With this method, a railway station is divided into five constituent systems. The structural components, nonstructural components, and especially professional equipment that affect the functions in each system are identified and analyzed. Significantly, a new calculation method for seismic resilience indices, encompassing repair cost, repair time, casualties, and resilience grade, is proposed. Additionally, the complete seismic resilience assessment process is outlined. Furthermore, a case study was conducted on a typical railway station in China to demonstrate the application of this new seismic resilience assessment method.

The Politics of Youth Representation at Climate Change Conferences: Who Speaks, Who Is Spoken of, and Who Listens?

Abstract In this article, we examine how young climate activists make use of the United Nations (UN) constituency system to give voice to children and youth in global climate governance. Our study is based on a mapping of accredited youth nongovernmental organizations (YOUNGO) as well as fieldwork at two UN Climate Change Conferences, where we conducted interviews, observed events, and analyzed plenary interventions. Informed by constructivist accounts of political representation, the article pays attention to the performative relationship between institutionalized means of youth representation and “the represented.” When analyzing our material, we asked who speaks for youth, how youth are spoken of, and how institutions shape representative speech. Our study identifies three subject positions that offer competing interpretations of who youth are as a political community and what they want. Rather than taking youth’s demands and interests as a starting point for representative politics, the article illustrates how the UN constituency system actively constructs youth and effectively molds young climate activists into professional insiders.

On the effective thermal conductivity of gallium-based liquid metal filled elastomers

Gallium based alloys are liquid at ambient temperature, combining both metal-like high thermal conductivity and fluidity characteristics, which contributes to their applications in thermal management, soft robotics, stretchable electronics and etc. A great number of experimental researches have been performed in preparing Ga-based liquid metal filled elastomers (LMFEs) with various constituent systems, processing techniques, droplet morphology and filler sizes in attempt to obtain the best thermal conductive efficiency. The thermal conductive mechanisms in these LMFEs are still lacking a comprehensive understanding up to date, and therefore the present work aimed to conduct a thorough analysis on this topic using both theoretical models and finite element method (FEM) simulations. The predictability of four classic micromechanics models was compared with the experiments and FEM simulations, and their relevant thermal conductive principles were identified from the simulated thermal flux evolution. Some deficiencies of these analytical models are identified and amended by reconsidering their special architectures. This work is favorable for establishing a general and quantitative relationship between the effective thermal conductivity and microstructures for most of the synthesized LMFEs available in the literatures.

The systematic review of variety of military, weapon, combat and warfare system-of-systems wuth their new classification and ontology depiction for further concept and design development for the Armed Forces of Ukraine

A system-of-systems is a special complex structure in which new capabilities arise from interacting independent pieces that are controlled by multiple operators. One special kind of similar structure are military, or weapon, system-of-systems. The architecture of weapon SoS consists of the constituent systems (pieces), of interfaces and IT, of communication and exchanges occurring between the systems. The architecture of the SoS is always in a state of flux, but in warfare thedemands to change the structure of weapon SoS are emphasized. To save lives and to win both in close battles and long war is the main mission of HQ, common combat forces and supporting efforts. In the article the architecture of created SoS in different countries (mainly in U. S., but also in NATO and P. R. C.) are presented – their schemes, components, purposes and key peculiarities. These features allow to get the ontology for typical variant of SoS – they all were divided into five classes. So, we suppose that SoS may by differed by their creation, or evolution, or transition, or combination, or due to attaching to non-SoS. In general, the development planning of the military or weapon SoS is a challenging strategic analysis work because it involves various aspects, such as mission tasks, capability requirements, weapon effectiveness, and economic benefits. But in demands of lifesaving in warfare the expectable replacing soldiers via an autonomous vehicle SoS are straightforward, so it is need to understand the concept and main features of SoS.

A framework for the design of fault-tolerant systems-of-systems

Context:Systems-of-Systems (SoS) increasingly permeate everyday life in various critical domains. Due to their dynamic nature, guaranteeing their fault tolerance is challenging. Fault-tolerant SoS must deal with behavioral changes in constituent systems, whether accidental or deliberate. Goal:This work proposes ReViTA, a framework to assist professionals in designing fault-tolerant SoS that can continue to provide their function even in the presence of disturbances, i.e., events that affect the ability of an SoS to fulfill its mission. Methods:By adopting ReViTA, fault tolerance can be achieved by reconfiguring an SoS architecture to meet the critical mission requirements. Results:We performed two studies to evaluate the ReViTA acceptance by professionals. In the former, we gathered perceptions and suggestions from 14 professionals through individual interviews. In the latter, we involved a group of four professionals who applied ReViTA to a real-world scenario. Conclusion:The results demonstrate that ReViTA can effectively support professionals in designing fault-tolerant SoS. Employing ReViTA also brings insights into costs and planning that are crucial for implementing fault-tolerance strategies. Using ReViTA facilitates a comprehensive understanding of conflicts and weaknesses in constituent systems and fosters collaboration between domain experts and decision-makers. Employing ReViTA also improves stakeholder communication and enhances resource utilization.

Progress on the Properties of Ceramic Phase-Reinforced High-Entropy Alloy Composite Coatings Produced via Laser Cladding

The production of ceramic phase-reinforced high-entropy alloy composite coatings with excellent mechanical properties, high-temperature oxidation resistance, and corrosion resistance via laser cladding is a new hotspot in the field of surface engineering. However, as high-entropy alloys have a wide range of constituent systems and different kinds of ceramic particles are introduced in different ways that give the coatings unique microscopic organization, structure, and synthesized performance, it is necessary to review the methods of preparing ceramic phase-reinforced high-entropy alloys composite coatings via laser cladding. In this paper, the latest research progress on laser cladding technology in the preparation of ceramic phase-reinforced high-entropy alloy composite coatings is first reviewed. On this basis, the effects of ceramic particles, alloying elements, process parameters, and the microstructure and properties of the coatings are analyzed with the examples of the in situ generation method and the externally added method. Finally, research gaps and future trends are pointed out, serving as a reference for the subsequent research, application, and development of the preparation of ceramic phase-reinforced high-entropy alloy composite coatings.

Machine learning topological defects in confluent tissues

Active nematics is an emerging paradigm for characterizing biological systems. One aspect of particularly intense focus is the role active nematic defects play in these systems, as they have been found to mediate a growing number of biological processes. Accurately detecting and classifying these defects in biological systems is, therefore, of vital importance to improving our understanding of such processes. While robust methods for defect detection exist for systems of elongated constituents, other systems, such as epithelial layers, are not well suited to such methods. Here, we address this problem by developing a convolutional neural network to detect and classify nematic defects in confluent cell layers. Crucially, our method is readily implementable on experimental images of cell layers and is specifically designed to be suitable for cells that are not rod shaped, which we demonstrate by detecting defects on experimental data using the trained model. We show that our machine learning model outperforms current defect detection techniques and that this manifests itself in our method as requiring less data to accurately capture defect properties. This could drastically improve the accuracy of experimental data interpretation while also reducing costs, advancing the study of nematic defects in biological systems.

Thermodynamic Modeling of the Drowning-Out Crystallization Process for LiOH and CHLiO2

This study focuses on the thermodynamic modeling of the crystallization by the drowning process for two lithium salts: lithium hydroxide (LiOH) and lithium formate (CHLiO2). The modeling involves utilizing thermodynamic properties, such as the activity, osmotic, and solubility coefficients, within the ternary systems of LiOH + cosolvent + water and CHLiO2 + cosolvent + water, as well as their respective binary constituent systems. Ethanol is chosen as the cosolvent for both salts, facilitating a comparative analysis. Given the limited availability of thermodynamic data for lithium formate with different cosolvents, the study aims to address this gap. The modified Pitzer model was employed for the modeling process, where the parameters were successfully obtained for both systems, with a deviation of less than 1%. Additionally, the mass and energy balance for the drowning-out crystallization process of both salts was performed.

Enhanced Itinerant d0 Ferromagnetism and Tunable Topological Properties of a Ca2C/Ca2N Heterobilayer

AbstractRecent studies have shown that a rich variety of exotic physical phenomena can emerge from the presence of electronic flat bands. Using first‐principles calculations, here a monolayered Ca2C possesses a relatively flat band near the Fermi level, and across the whole Brillouin zone is predicted. Next, the weak d0 ferromagnetism in Ca2C is substantially enhanced by a proximity‐coupled electride monolayer of Ca2N is shown. The enhanced magnetism can be attributed to the straightening of the flat band caused by the charge transfer to the electride, while the flattening is tied to the magic ratio of three between the σ and π channels of the effective C─C coupling strength. More surprisingly, even though each of the constituent systems is topologically trivial, the Ca2C/Ca2N heterobilayer is empowered with nontrivial band topology, characterized by a high Chern number tunable by the magnetization orientation or lateral strain. These findings provide a new platform for realizing intriguing magnetic topological metals in 2D materials.