Constituent Systems Research Articles

Liquidus projection of Co-Sb-Yb ternary system

Co-Sb-Yb alloys at the Sb-rich corner were prepared. Their primary solidification phases were determined. Co-Sb-Yb liquidus projection is proposed based on the experimental results at the Sb-rich corner and the phase diagrams of its three constituent binary systems. There is no ternary phase in the Co-Sb-Yb system. The primary solidification phases along the Co-Sb, Sb-Yb and Yb-Co binary sides are Co, CoSb, CoSb2, CoSb3, Sb, YbSb2, YbSb, Yb11Sb10, Yb4Sb3, α-Yb5Sb3, β-Yb5Sb3, Yb, Yb2Co17, YbCo3 and YbCo2, respectively.

Liquidus Projections of Bi-Se-Ga and Bi-Se-Te Ternary Systems

This study determines the liquidus projections of both Bi-Se-Ga and Bi-Se-Te ternary systems which are constituent ternary systems of promising Bi-Se-Te-Ga thermoelectric materials. Ternary Bi-Se-Ga and Bi-Se-Te alloys are prepared. Their primary solidification phases are experimentally determined, and thermal analysis experiments are carried out. The liquidus projections are determined based on the ternary experimental results and phase diagrams of constituent binary systems. The Bi-Se-Ga system includes seven primary solidification phases, Bi, Ga, GaSe, Ga2Se3, Se, Bi2Se3, and (Bi2)n(Bi2Se3)m. In the Bi-Se-Te system, there are five primary solidification phases, Bi, (Bi2)n(Bi2Te3)m, Bi2(Se,Te)3, (Se,Te), and (Bi2)n(Bi2Se3)m. Both the (Bi2)n(Bi2Te3)m and (Bi2)n(Bi2Se3)m phases are not a single phase, but a collection of series undetermined phases. Large miscibility gaps are observed in the Bi-Se-Ga system. The temperatures of the invariant reactions, Liquid + Bi + GaSe = Ga and Liquid + Ga2Se3 = Bi + GaSe, are at 495 K (222 °C) and 533 K (260 °C), respectively.

Preliminary design of safety and interlock system for indian test facility of diagnostic neutral beam

Indian Test Facility (INTF) is being built in Institute For Plasma Research to characterize Diagnostic Neutral Beam in co-operation with ITER Organization. INTF is a complex system which consists of several plant systems like beam source, gas feed, vacuum, cryogenics, high voltage power supplies, high power RF generators, mechanical systems and diagnostics systems. Out of these, several INTF components are ITER deliverable, that is, beam source, beam line components and power supplies. To ensure successful operation of INTF involving integrated operation of all the constituent plant systems a matured Data Acquisition and Control System (DACS) is required. The INTF DACS is based on CODAC platform following on PCDH (Plant Control Design Handbook) guidelines.The experimental phases involve application of HV power supplies (100KV) and High RF power (∼800KW) which will produce energetic beam of maximum power 6MW within the facility for longer durations. Hence the entire facility will be exposed tohigh heat fluxes and RF radiations.To ensure investment protection and to provide occupational safety for working personnel a matured Safety and Interlock system is required for INTF. The Safety and Interlock systems are high-reliability I&C systems devoted completely to the specific functions. These systems will be separate from the conventional DACS of INTF which will handle the conventional control and acquisition functions. Both, the Safety and Interlock systems are based on IEC 61511 and IEC 61508 standards as prescribed by the ITER PCDH guidelines.

自動運転車を取り巻くSystem of Systemsのシステムモデル構築

In this paper, system models for system of systems (SoS) involving automated vehicles are derived based on analysis of the context where the constituent systems, such as the automated driving system, the ego vehicle driver, surrounding mobility, pedestrians, information communication technologies, transport infrastructure systems, physical environment, and natural environment, interact. The safety requirements are defined through refinements of the system models utilizing system safety relationship among hazards, hazard contexts and harm. From the safety requirements for constituent systems, those functional architectures are defined including the behavior and the structure of each constituent system.

Use of System of Systems and Decentralized Optimization Concepts for Integrated Traffic Control via Dynamic Signalization and Embedded Speed Recommendation

In the frame of the European research project Local4Global, urban traffic control is one of the demonstrative use cases of a developed decentralized control method based on the Technical System of Systems (TSoS) concept and using machine learning capabilities. TSoS concept consists of dividing the system to semiautonomous elementary systems, called constituent systems, which shall enjoy to a major extent a local decision possibility. A remaining part of the decision shall be made after exchanging information between all participating systems to learn from each other and improve the overall performance.In the traffic context, two basic classes of constituent systems are suggested: dynamically signalized traffic junctions and connected vehicles with speed control capabilities. Both traffic signals and vehicle speed controls receive a correction from the L4GCAO global optimizer in a bigger and common control cycle, namely each day.This paper describes the methodology and the results of a VISSIM microscopic traffic simulation of a road section situated near Munich. For the strategy evaluation, the results in terms of the performance index, waiting time per link, coordination proportion, mean network speed and travel time are compared to a baseline. This is during off peak demand a currently running fixed green wave signalization and during rush hour demand on the evening time of day signalization, having additional both demands combined with a speed recommendation with corrections. First results show that during rush hour the overall performance is improved compared to the initial scenario, nevertheless in low demands opposite situation is observed.A general advantage of such method is that it is easily scalable and transposable to other portions of the network. Since machine learning capabilities are introduced, algorithms are self-adaptive to yearly and seasonally varying demand and no important human involvement is needed. An outlook is given, how to transfer the strategy to the real road and test it in a field test.

自動運転車を取り巻くSystem of Systemsの構成システムに対する安全性要求の明確化

In this paper, the safety requirements for constituent systems in system of systems (SoS) involving automated vehicles are defined based on the system models. Safety information related to the constituent systems is derived from the behaviour model of SoS to describe the safety requirements using SafeML (Safety modelling language), which is designed for modelling the safety-related concerns of a system using concepts of hazard, harm context, harm and defence. Safety functions for the constituent systems are derived from the defences to mitigate occurring harms, which are described by SafeML and also used in design of the automated driving system. It is shown from the description by SafeML that safety can be considered early in the design stage managing its complexity for the automated driving system.

Multiphysics Computational Modeling in $\boldsymbol{\mathcal{C}}\mathbf{Heart}$

From basic science to translation, modern biomedical research demands computational models which integrate several interacting physical systems. This paper describes the infrastructural framework for generic multiphysics integration implemented in the software $\boldsymbol{\mathcal{C}}\mathbf{Heart}$, a finite-element code for biomedical research. To generalize the coupling of physics systems, we introduce a framework in which the geometric and operator relationships between the constituent systems are rigorously defined. We then introduce the notion of topological interfaces and define specific operators encompassing many common model coupling requirements. These interfaces enable the evaluation of weak form integrals between mesh subregions of arbitrary finite-element bases' orders, types, and spatial dimensions. Equation maps are introduced which provide abstract representations of the individual physics systems that can be automatically combined to permit a monolithic matrix assembly. Flexible solution strategies for the resulting coupled systems are implemented, permitting fine-tuning of solution updates during fixed point iterations, and subgrouping where several problems are being solved together. Partitioning of coupled mesh domains for optimal load balancing is also supported, taking into account the per-processor cost of the entire coupled problem within the graph problem. The demonstration of the performance is illustrated through important real-world multiphysics problems relevant to cardiac physiology.

Calculation of NaCl, KCl and LiCl Salts Activity Coefficients in Polyethylene Glycol (PEG4000)–Water System Using Modified PHSC Equation of State, Extended Debye–Hückel Model and Pitzer Model

AbstractFor biomolecules and cell particles purification and separation in biological engineering, besides the chromatography as mostly applied process, aqueous two-phase systems (ATPS) are of the most favorable separation processes that are worth to be investigated in thermodynamic theoretically. In recent years, thermodynamic calculation of ATPS properties has attracted much attention due to their great applications in chemical industries such as separation processes. These phase calculations of ATPS have inherent complexity due to the presence of ions and polymers in aqueous solution. In this work, for target ternary systems of polyethylene glycol (PEG4000)–salt–water, thermodynamic investigation for constituent systems with three salts (NaCl, KCl and LiCl) has been carried out as PEG is the most favorable polymer in ATPS. The modified perturbed hard sphere chain (PHSC) equation of state (EOS), extended Debye–Hückel and Pitzer models were employed for calculation of activity coefficients for the considered systems. Four additional statistical parameters were considered to ensure the consistency of correlations and introduced as objective functions in the particle swarm optimization algorithm. The results showed desirable agreement to the available experimental data, and the order of recommendation of studied models is PHSC EOS > extended Debye–Hückel > Pitzer. The concluding remark is that the all the employed models are reliable in such calculations and can be used for thermodynamic correlation/predictions; however, by using an ion-based parameter calculation method, the PHSC EOS reveals both reliability and universality of applications.

Complexity and fragility in system of systems

SoS are an ensemble of complex systems, which have the potential for an extraordinary amount of structural complexity, even temporarily, as a result of interconnections and couplings that can vary in strength. Because of this, SoS can be vulnerable to sudden catastrophic collapse as a result of small and insignificant partial functionality losses in one of the constituent systems. This paper provides an analysis of the response SoS to uncertainties in the form of partial failures, which is complemented by the presentation of a measure of structural complexity for SoS. Experiments with the development of random graphs to simulate SoS show that a partial failure initiated in one system has a high possibility of leading to a collapse of another system of SoS, sometimes even before leading to total failure in the originating system. After pinpointing the effect of the complexity of today's system of systems (SoS), we present a first-step understanding of why unanticipated failures find more potential and more pathways to their occurrence when interventions in SoS operations, standards or processes are conducted without enough insight and without consideration of the fundamental nature of complexity. We then demonstrate a condition where the incremental changes actually lead to failure of the SoS to meet its performance parameters.

Modeling Resilience in System of Systems Architecture

System of Systems (SoS) can be represented by the SoS architecture which defines the constituent systems and their interfaces. SoS delivers capabilities beyond what the systems working independently can provide. Resiliency of the SoS is becoming increasingly more important and necessary for mission success. Resiliency can be defined as the ability of the SoS architecture to defend against emerging threats. This defense means adapting the SoS architecture to handle the new threat. As a new threat is uncovered, the SoS architecture evolves to a new SoS architecture resilient to the new threat. This paper presents a novel approach to modeling SoS resilience using the SoS architecture as represented in Department of Defense Architecture Framework (DoDAF) views. DoDAF views are required for US DoD programs and are a way of common communication among stakeholders. This modeling approach uses an executable agent-based model of the SoS that includes the SoS architecture and possible threats. The initial SoS architecture is taken from the appropriate DoDAF views. The modeling approach introduces a threat and then adapts the SoS architecture to handle the threat. In this way, resiliency is increased. Finally, the DoDAF views are updated to reflect the newly adapted SoS architecture.

Driver's Functions Definition in System of Systems Surrounding Automated Vehicles

Graduate School of System Design and Management, Keio Universit yAbstract : This paper addresses the definition of the driver ’s functions for an automated vehicle of level 3, as defined by the Society of Automotive Engineers. By combining th e constituent systems surrounding the automated vehicles in specific use cases, their interactions co uld be refined in a stepwise approach. This approach enables traceability of interactions betw een drivers, automated driving systems, and other constituent systems.Key Words : System of Systems; Systems Engineering; Automated Vehicle; S ystem Modeling Language* 교신저자 : Satoko Kinoshita, s.kinoshita@keio.jp* This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License(http://creativecommons.org/licenses/by-nc/3.0) which pe rmits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

On the formal interpretation and behavioural consistency checking of SysML blocks

The Systems Modeling Language (SysML) is a semi-formal, graphical modelling language used in the specification and design of systems. We describe how Communicating Sequential Processes (CSP) and its associated refinement checker, FDR3, may be used to underpin an approach that facilitates the refinement checking of the behavioural consistency of SysML diagrams. We achieve this by utilising CSP as a semantic domain for reasoning about SysML behavioural aspects: activities and state machines are given a formal, process-algebraic semantics. These behaviours execute within the context of the structural diagrams to which they relate, and this is reflected in the CSP descriptions that depict their characteristic patterns of interaction. We describe how CSP and FDR3 can be used in conjunction with SysML in a formal, top-down approach to systems engineering. Moreover, the compositionality afforded by CSP alleviates the state space explosion problem frequently encountered with complex formal models and complements the top-down approach of SysML. Typically, a system is composed from constituent systems using the concept of blocks. SysML permits two alternative interpretations with regard to the behaviour of the resulting composition. We argue that the use of a process-algebraic formalism enables us to explore the relationships between these interpretations in a more rigorous fashion than would otherwise be the case.

Co-In-Sb Ternary System (I): Isothermal Sections and Liquidus Projection

The Co-In-Sb ternary system has thermoelectric application interests. Co-In-Sb ternary alloys are prepared in this study. Their equilibrium phases at 1123.15 K and 923.15 K (850 °C and 650 °C) as well as their primary solidification phases and univariant reaction temperatures are determined. The isothermal sections at 1123.15 K and 923.15 K (850 °C and 650 °C) and the liquidus projection of the Co-In-Sb ternary system are determined based on the ternary experimental results, the phase diagrams of its three constituent binary systems, and the limited phase equilibria literature. No ternary compounds are found. The phase relationships at both 1123.15 K and 923.15 K (850 °C and 650 °C) are the same. There are five phases, seven two-phase regions, and three tie-triangles which are Co-CoSb-liquid, CoSb-CoSb2-liquid, and CoSb2-CoSb3-liquid. In the liquidus projection, there are nine primary solidification phase regions, Co, CoSb, CoSb2, CoSb3, Sb, InSb, In, CoIn2, and CoIn3. There are seven invariant reactions which are two Class I, four Class II, and one Class III.

Advances in novel carrier systems of chemical constituents from spice volatile oils

Recent years, chemical constituents from spice volatile oils have gained worldwide concern owing to its multiple pharmacological effects and safety for using as the natural antibacterial agents. However, their poor dissolution, strong volatility, serious irritation, weak stability, easy oxidation and low bioavailability characteristics are the major obstacle in the preparation of effective oral formulation and practical application. Therefore, there is an urgent need to select a novel carrier system that can delivery the chemical constituents from spice volatile oils more efficiently with improving their stability as well as alleviating the irritation, and develop the functional food, health products and even medicine for exerting their pharmacological effects, which also is the focus and nodus of the research on their application. This review presents recent systematic studies on their novel carrier systems, including cyclodextrin inclusion complex, liposomes, nanoemulsions, nanoparticles, solid dispersion and so on, and summarizes the characteristics, application range and problems of each novel carrier systems, in order to provide some beneficial thoughts in further developing new products of chemical constituents from spice volatile oils.

Stability of stochastic nonlinear systems in cascade with not necessarily unbounded decay rates

This paper develops tools to verify stability and robustness of cascaded nonlinear stochastic systems based on Lyapunov functions. Constituent systems are formulated in terms of integral input-to-state stability (iISS) and input-to-state stability (ISS) which are popular notions for both stochastic and deterministic systems. This paper highlights differences between the stochastic and the deterministic cases. In contrast to deterministic systems, it is demonstrated that assuming ISS systems having unbounded decay rates in dissipation inequalities is restrictive. Taking this fact into account, stability criteria are formulated without assuming unboundedness of decay rates, so that ISS systems with bounded decay rates and iISS systems which are not ISS are covered in a unified manner. Stability criteria for stochastic cascades involve the growth rate conditions at connecting channels. This paper clarifies how noise diffusion fields affect the growth rate conditions and the influence depends on definition of stochastic robustness.

Multicomponent phase behavior predictions using QSPR-generalized NRTL and UNIQUAC models

Multiphase, multicomponent equilibrium systems are encountered commonly in the chemical industry. The non-random two-liquid (NRTL) and universal quasi-chemical (UNIQUAC) models are applied widely to correlate activity coefficients in phase equilibria calculations. We demonstrated previously the predictive capability of a quantitative structure–property relationship (QSPR)-generalized NRTL model (NRTL-QSPR) for vapor–liquid equilibrium (VLE) property predictions of diverse binary systems. In this study, we further evaluate the prediction quality of the NRTL and UNIQUAC models as they apply to multicomponent systems. Specifically, we evaluate both the representation and prediction of vapor–liquid equilibrium properties of multicomponent systems using regressed and QSPR-generalized parameters of the constituent binaries.To complete this evaluation, a database comprised of 57 ternary VLE systems and their 75 constituent binary systems was assembled. In addition, 29 ternary systems were employed to examine the efficacy of the models when at least one constituent binary is missing.For ternary systems where all three constituent binary systems were available, the NRTL-QSPR model provided overall percent absolute average deviations (%AADs) of 3.7, 0.3, 9.0, and 8.7 for pressure (P), temperature (T), mole fraction (y1), and K-values, respectively. In comparison, the generalized UNIQUAC-QSPR model exhibited errors of 3.5, 0.3, 8.2, and 7.9, respectively. Thus, for the systems considered, both models exhibit comparable accuracy. Further, for these systems the group-contribution method Modified UNIFAC (mUNIFAC) produced slightly better results.For systems where at least one constituent binary is missing in our database, errors for the NRTL-QSPR are 6.3, 0.5, 11.2, and 11.4 %AADs for P, T, y1, and K-values, respectively. The comparable errors for the UNIQUAC-QSPR for this case are 8.4, 0.7, 12.9, and 12.5, respectively. For the same set of ternary systems, the mUNIFAC model produced %AADs of 20.7, 2.1, 25.7, and 26.7 for P, T, y1, and K-values, respectively. As such, the mUNIFAC model results in three times higher errors than our generalized models. Although additional evaluation using a comprehensive database is required, the results presented in this study demonstrate the efficacy of the QSPR binary parameter generalizations, as applied to the NRTL and UNIQAC models, for VLE multicomponent property predictions.

Integrating an Upgraded Constituent System in a System of Systems: A SysML Case Study

AbstractA system of systems (SoS) relies on each constituent system contributing towards achieving some global emergent behavior. Integrating constituent systems can be particularly challenging for SoS engineering, partly because of the independence of the constituents and the difficulty of producing a realistic, scalable test environment before changes are deployed to the live environment. For this reason modeling and simulation can be important tools for regression testing within an integration scenario. We provide a worked example of an SoS integration scenario using a traffic management system as demonstrator, employing a structured, model‐based framework (the COMPASS Integration Framework) designed for integrating CSs in a variety of SoS integration scenarios. The Framework is designed to be used with architectural modelling views (we use SysML for our case study). Finally, we provide some pointers for future work and next steps.

Model‐based Engineering of Emergence in a Collaborative SoS: Exploiting SysML & Formalism

AbstractA collaborative SoS is a system composed of constituent systems (CSs), which are independent and voluntarily cooperate without an agreed SoS director. Engineering emergent behaviour is just one of the key engineering challenges for which support is needed. In this paper we illustrate for the first time an integrated collection of model‐based techniques for verifying behaviours and properties, with the aim of assisting the engineering of collaborative systems of systems (SoSs). We provide an illustration of an approach that flows from requirements and architectural modelling to the use of formal techniques, integrating methods drawn from software and systems engineering fields to tackle engineering challenges in SoS. The approach incorporates architectural modelling (implemented in SysML) before transitioning to a formal modelling notation which has been developed specifically for SoSs. This formal modelling approach supports a wide range of analysis and verification techniques, such as: design space exploration; requirements verification; and consistency checks. We also discuss how our approach can be incorporated into a standard systems engineering approach.

Designing Resilient Systems‐of‐Systems: A Survey of Metrics, Methods, and Challenges

ABSTRACTResilience is the ability of a system to react to and recover from disturbances with minimal effect on its dynamic stability. While resilience has been the focus of research in several fields, in the case of systems‐of‐systems (SoSs), addressing resilience is particularly interesting and challenging. As infrastructure SoSs, such as power, transportation, and communication networks, grow in complexity and interconnectivity, measuring and improving the resilience of these critical SoSs is vital in terms of safety and providing uninterrupted services. While the resilience of SoSs depends on the reliability of their constituent systems, traditional reliability and risk assessment approaches cannot adequately quantify their resilience. In this paper, we provide an evaluation of the various methods available and challenges associated with designing resilient SoSs by (1) indicating important differences between resilience and various related system attributes, (2) providing a critical assessment of the current reliability and risk techniques in addressing SoS resilience, and (3) discussing the application of recent multidisciplinary research that can guide the design of resilient SoS. Finally, we highlight key challenges in this design process and propose a series of research themes that can shape future research in this field.

Systems of Systems Engineering

The term “System of Systems” (SoS) has been used since the 1950s to describe systems that are composed of independent constituent systems, which act jointly towards a common goal through the synergism between them. Examples of SoS arise in areas such as power grid technology, transport, production, and military enterprises. SoS engineering is challenged by the independence, heterogeneity, evolution, and emergence properties found in SoS. This article focuses on the role of model-based techniques within the SoS engineering field. A review of existing attempts to define and classify SoS is used to identify several dimensions that characterise SoS applications. The SoS field is exemplified by a series of representative systems selected from the literature on SoS applications. Within the area of model-based techniques the survey specifically reviews the state of the art for SoS modelling, architectural description, simulation, verification, and testing. Finally, the identified dimensions of SoS characteristics are used to identify research challenges and future research areas of model-based SoS engineering.