Interdependent Subsystems Research Articles

Spatial and Temporal Dynamics of Homestays on Chongming Island: A Systemic Analysis in the Context of World-Class Eco-Island Development

As the development of world-class eco-islands progresses, the homestay sector on Chongming Island has burgeoned, emerging as a pivotal catalyst for rural tourism and economic prosperity. This study, leveraging Chongming Island as a case study, systematically analyzes the spatiotemporal distribution of homestays across island-wide, township, and village scales, employing methodologies such as the spatiotemporal evolutionary tree model. It delves into the intricate systemic framework underpinning homestay development, elucidating the dynamics of interaction mechanisms. Furthermore, it examines the evolving roles of diverse stakeholders throughout various developmental phases, grounded in stakeholder theory. The study reveals that (1) Chongming’s homestays on the island, townships, and village scales show very obvious agglomeration characteristics, mainly concentrated in the A-level scenic spots and in and out of the island traffic junction. (2) The growth of homestays in Chongming shows an increasing trend year by year, with the growth rate slowing down after 2020, and can be divided into four main phases, which are closely related to the construction phase of the eco-island. (3) The evolution of Chongming Island’s homestay is a multifaceted natural–human system intricately shaped by a confluence of five interdependent subsystems: natural ecology, social culture, multiple stakeholders, geographical location, and transport infrastructure. At different stages of development, under the synergistic effect of multiple stakeholders, the homestays on Chongming Island eventually formed a governance structure led by the government and co-managed by the development company, external entrepreneurs, and local villagers. These insights not only augment the scholarly discourse on stakeholder dynamics within the homestay industry but also offer pragmatic enlightenment for strategic planning and the advancement of holistic urban–rural integration in Chongming and the broader Shanghai region.

POSTURAL CONTROL IMPAIRED IN MYOARTHROKINETIC AND NEURO-SENSORY DISORDERS

Interdependent subsystems involved in dynamic posture and locomotion are represented by osteoarticular, neuromuscular, sensory systems. Postural control is maintained by somato-sensory, visual vestibular feedback, integrated at the level of the locomotor system and the central nervous system. Postural stability is disturbed in mio-arthro-kinetic disorders. In proprioceptive loss, the automatic postural responses are diminished in amplitude and delayed in time; stretch reflexes in soleus and medial gastrocnemius are severely diminished; balance-correcting responses in tibialis anterior are diminished and delayed; backward motion of the trunk is reduced; movement strategies and synergies are disturbed. In peripheral vestibular loss, there are increased trunk responses to disruptive stimuli, with hypermetric trunk muscle responses and hypometric knee responses, but unchanged synergies; pathological changes to the modulation depth are produced; the amplitude of balance correcting responses in ankle muscles is severely reduced. Visual input serves to decrease the stiffness of the musculoskeletal system; it can be accomplished by decreasing the level of muscular activity across the joints of the lower limbs (in eyes-open subjects) or by reducing the gains of the other postural feedback mechanisms, the proprioceptive or vestibular systems (in eyes-closed subjects). Keywords: postural control, proprioceptive insufficiency, vestibular impairment.

The Gompertz Law emerges naturally from the inter-dependencies between sub-components in complex organisms

Understanding and facilitating healthy aging has become a major goal in medical research and it is becoming increasingly acknowledged that there is a need for understanding the aging phenotype as a whole rather than focusing on individual factors. Here, we provide a universal explanation for the emergence of Gompertzian mortality patterns using a systems approach to describe aging in complex organisms that consist of many inter-dependent subsystems. Our model relates to the Sufficient-Component Cause Model, widely used within the field of epidemiology, and we show that including inter-dependencies between subsystems and modeling the temporal evolution of subsystem failure results in Gompertizan mortality on the population level. Our model also provides temporal trajectories of mortality-risk for the individual. These results may give insight into understanding how biological age evolves stochastically within the individual, and how this in turn leads to a natural heterogeneity of biological age in a population.

Transport, Interaction, and Connectivity

Abstract Transport research is a multidisciplinary field that extends beyond technical aspects. As such, it can provide significant insights into societies, economies, and cultures. In this study, we take a broader perspective that encompasses transport, interaction, and connectivity. These three terms are interconnected, with transport and interaction being interdependent sub-systems. Transport research encompasses means of transport, local, regional, and supra-regional networks, transport infrastructure, and the items transported. In turn, interaction research focusses on interaction networks, groups, and intensities. The concept of connectivity adds a layer of complexity, enabling a better understanding of the sub-systems and the system as a whole by considering the balance of opportunities and limitations. This article aims to demonstrate how the various approaches and concepts are related and to outline an integrated and systematic research approach.

Structural modeling and analysis of fuel cell: a graph-theoretic approach.

A fuel cell, an energy conversion system, needs analysis for its performance at the design and off-design point conditions during its real-time operation. System performance evaluation with logical methodology is helpful in decision-making while considering efficiency and cross-correlated parameters in fuel cells. This work presents an overview and categorization of different fuel cells, leading to the developing of a method combining graph theory and matrix method for analyzing fuel cell system structure to make more informed decisions. The fuel cell system is divided into four interdependent sub-systems. The methodology developed in this work consists of a series of steps comprised of digraph representation, matrix representation, and permanent function representation. A mathematical model is evaluated quantitatively to produce a performance index numerical value. With the aid of case studies, the proposed methodology is explained, and the advantages of the proposed method are corroborated.

Coalition cascades: The politics of tipping points in clean energy transitions

AbstractPolicy change often involves multiple policy subsystems, as in the case of clean energy transitions. We argue that trans‐subsystem policy feedback is a central dynamic in policy change across subsystems. Policy in one subsystem creates benefits/costs and/or learning effects that mobilize actors for policy change in another subsystem, resulting in “coalition cascades” across interdependent subsystems. If coalition cascades lead to the resolution of coordination problems across subsystems, the system reaches a tipping point in policy change. Coalition cascades are thus the transmission belts of trans‐subsystem policy feedback. We illustrate our argument in the case of California's clean energy transition. We show how early renewable energy policy spilled over into the subsystems on grid policy—leading to energy storage policy—and on transport policy—resulting in electric vehicle charging policy. The article advances our understanding of the mechanisms underpinning trans‐subsystem policy change, offering a model of the politics of tipping points.

Perceptions of the academic community on the performance of sustainable development initiatives in higher education

AbstractSince the UN Conference on the Human Environment was held in Stockholm in 1972, higher education institutions (HEIs) have been adapting to assume their social role in supporting societies in promoting sustainable lifestyles. However, HEIs are complex institutions composed of several interdependent subsystems. Sustainable improvement requires holistic assessment measures to comply with established goals. To date, few studies have focused on comparing the different perceptions of sustainability in HEIs and considering the views of the academic community in shaping the efforts and better disseminating sustainable development initiatives. To fill this gap, this work aimed to implement a methodology that compares the perceptions of sustainability and the implemented actions among members of HEIs to show the discrepancies between perceptions and facts. Many studies report either the perception of members of the academic community or the technical assessment of the sustainable performance of the institution in isolation. The novelty of this work lies in developing a tool that allows the use of a similar scale to compare the perception of users of academic services with the valuation attributed by technicians responsible for implementing sustainable development initiatives at HEIs. Analysing of these results enables the identification of dimensions with discrepancies, guiding managers as they carry out actions to promote greater community engagement in implementing sustainability initiatives that boost the consolidation of these values in the institutional culture. Additionally, it is highlighted that the proposed methodology could be adapted for use in other types of institutions, maintaining the same benefits described here.

The role of human factors in aviation ground operation-related accidents/incidents: A human error analysis approach

Aviation is a complex socio-technical system with interconnected and interdependent subsystems, such as flight operations, air traffic control, aircraft maintenance and ground operations. However, safety and risk research has not paid, thus far, adequate attention to all subsystems, resulting in possibly undetected or underestimated risks. This study focuses on Ground Operations (GO) as a subsystem and analyses the role of human factors in ground operations related accidents and incidents. 87 accident and incident reports (from 2000 to 2020) were analysed in three stages, using the Human Factors Dirty Dozen (HF DD) Model and the Human Factors Analysis and Classification Scheme (HFACS) as a basis for the third stage, a systematic thematic analysis. The findings indicate that lack of situational awareness and failure to follow prescribed procedures are the main causal and contributing factors in GO-related accidents and incidents. Three operational actions were identified as most critical: aircraft pushback/towing, aircraft arrival and departure, and aircraft weight and balance. An agenda for future research and recommendations for industry corrective action are proposed.

Experience of designing and implementing integrated system of technological preparation of productionfor manufacturing new aircraft engines

The technological preparation of production (TPV) is one of the key stages of the product life cycle (LPL) when designing and developing new aircraft engines. The TPV system foresees the use of the following instruments: CAD/CAM/CAE systems to ensure the implementation of the following operations: automated design, production and engineering calculations; Product Data Management systems (PDM) to ensure product data management; Enterprise resource planning (ERP) systems for the corporate resource planning. Note that the instruments above are combined into PLM-systems to provide information support for the TPV system. The paper reviews the experience of designing and implementing the integrated TPV system at Motor Sich JSC for the purpose of manufacturing new aircraft engines. The author presents a structural diagram of the implemented integrated system containing a complex of interdependent subsystems along with a description of the system of automated design of process documents, which provides for the on-line design of production processes. The paper gives a description of subsystem of automated preparation of programs for CNC machine tools, which is designed to calculate the trajectory of the cutting tool when machining geometrically complex parts of aircraft engines. The paper specifies the subsystem of automated design of technological equipment, which is in compliance with requirements for modern tool production. The author underlines that the system of automated design of production equipment saw the following design subsystems reaching the highest level of development: subsystems for designing cutting and gear machining tools; subsystems for designing machine tools; subsystems for designing the monitoring and metering instrument; subsystems for designing foundry and stamping equipment; subsystems for designing control of gear cutting tools as per electronic standards. It is noted that the automated subsystems of analyzing production processes allow for performing the following analyses: analyzing metal casting processes; analyzing stamping processes; analyzing cutting processes; analyzing gear-cutting processes. The author provides the following results of implementing the integrated system of technological preparation of production at Motor Sich JSC: i) The TPV period was increased by 1.2–1.5 times, and ii) The efficiency of design and construction works was raised by 3–3.5 times.

Организационно-экономический механизм тарифного регулирования естественных монополий

The sphere of natural monopolies affects the interests of the economy, both global and national scale. In Russia, this is a large system governed by a single law, which requires significant public costs for its existence and functioning. The peculiarity of such systems is the combination of interrelated and interdependent subsystems united by common goals. Taking into account the fact that the current regulatory organization does not allow forming a single management chain for planning, decision-making and stimulating efficiency for all types of natural monopolies, an organizational and economic mechanism of tariff regulation has been developed, in which it is proposed to use the advantages of digital information processing in the form of a navigator for regulating natural monopolies to obtain reliable information about the regulated entity and reducing the costs for its processing The interaction of key factors and the interaction of their elements is presented. The goal is to improve the quality of regulation and control of the activities of natural monopolies and, as a result, to reduce the public costs of regulation.

Role of the personnel practitioner in the identification and handling of communication problems in organisations

The scope of the personnel practitioners' role has, over the past decade, grown from the traditional activities of inter alia, manpower recruitment, selection and training to include organisational diagnoses and maintaining and improving organisational effectiveness and the quality of work life of employees. The complex organisation in which the practitioner has to fulfil these roles, consists of differentiated but interdependent sub-systems linked by resource and information flows. Information can be described as the bloodstream of an organisation and communication channels as the arterial system. To fulfil his role the personnel practitioner has to have means and instruments to gather information on all relevant aspects of organisation and its sub-systems. In this paper the important role of information in organisational functioning and behaviour is described, as well as ways to gather information systematically and how the personnel practioner can use ] this information to maintain and improve organisational effectiveness and the quality of work life of employees

Cybersafety: A System-Theoretic Approach to Identify Cyber-Vulnerabilities & Mitigation Requirements in Industrial Control Systems

Recent cyber-physical attacks, such as <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Stuxnet, Triton</i> etc., have invoked an ominous realization about the vulnerability of critical infrastructure, including water, power and gas distribution systems. Traditional IT security-biased protection methods that focus on improving <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">cyber hygiene</i> are largely impotent in the face of targeted attacks by advanced cyber-adversaries. Thus, there is an urgent need to analyze the safety and security of critical infrastructure in a holistic fashion, leveraging the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">physics</i> of the cyber-physical system. System-Theoretic Accident Model & Processes (STAMP) offers a powerful framework to analyze complex systems; hitherto, STAMP has been used extensively to perform safety analyses but an integrated safety and cybersecurity analysis of industrial control systems (ICS) has not been published. This paper uses the electrical generation and distribution system of an archetypal industrial facility to demonstrate the application of a STAMP-based method – called <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Cybersafety</i> – to identify and mitigate cyber-vulnerabilities in ICS. The key contribution of this work is to differentiate the additional steps required to perform a holistic cybersecurity analysis for an ICS of significant size and complexity and to present the analysis in a structured format that can be emulated for larger systems with many interdependent subsystems.

Parents’ self-concept clarity, marital satisfaction and parent-child relationship quality: Actor-partner interdependence analyses

The family can be viewed as an integrated system consisting of interdependent subsystems, among which marital and parent–child subsystems are critical for family functioning. Given the dominance of parents in the family, it is important to investigate the associations between parents’ characteristics and these two subsystems. In addition, researchers have found a unidirectional effect of parents’ self-concept clarity on their children’s self-concept clarity. Exploring whether and how parents’ self-concept clarity is related to family relationships may provide insight into this intergenerational transmission since the family plays an important role in the development of children’s self-concept. Taken together, the main aim of this study was to examine the links across parents’ self-concept clarity and marital and parent–child relationships. A total of 363 Chinese parental dyads of primary and secondary students completed the self-concept clarity, relationship assessment, and child–parent relationship scales, and the data were analyzed by adopting the actor–partner interdependence model (APIM) and the actor–partner interdependence mediation model (APIMeM). The APIM results indicated significant positive associations between parents’ self-concept clarity and parent–child relationship quality perceived by the parents (actor effects) and their partners (partner effects). The APIMeM results showed that fathers’ marital satisfaction partially mediated the actor effects from parents’ self-concept clarity to parent–child relationship quality. Moreover, after controlling for covariates (e.g., family income), parents’ self-concept clarity had significant indirect partner effects on parent–child relationship quality mediated completely via fathers’ marital satisfaction. These findings contribute to a deeper understanding of family system processes and the intergenerational transmission of self-concept clarity and have implications for family interventions.

Dynamic modeling and intelligent hybrid control of pressurized water reactor NPP power transient operation

The pressurized water reactor (PWR) is a combined system of several interdependent subsystems that face uncertainties and consist of critical parameters that initiate potential accidents. Therefore, a PWR needs to be controlled continuously for safe operation over its lifetime. To this end, a particle swarm optimization algorithm (PSO) optimized radial basis function neural network (RBF) proportional integral derivative (PID) control approach (PSO-RBF-PID) is proposed to regulate the PWR power at the desired level. The controller computes the control rod speed to optimize the output power to track the reference value. The performance, sensitivity, and stability of the controller are evaluated. The simulation results verified that the control strategy monitors the PWR power successfully and smoothly under different power levels as compared to the PSO-PID method. This study gives the benefit to apply the PSO-RBF-PID control technique for control applications in other nuclear engineering fields.

Machine Learning Enabled Design Automation and Multi-Objective Optimization for Electric Transportation Power Systems

This article presents an automated design and optimization framework for electric transportation power systems (ETPS) enabled by machine learning (ML). The use of physical models, simulations, and optimization methods can greatly aid the engineering design process. However, when considering the optimal co-design of multiple interdependent subsystems that span multiple physical domains, such model-based simulations can be computationally expensive, and traditional metaheuristic optimization methods can be unreliable. Bayesian optimization (BO), an ML framework, paves one feasible pathway to realize an efficient design process practically. However, current state-of-the-art BO algorithms are non-compatible or perform poorly when applied to system-level ETPS design with multiple objectives and constraints. This article proposes a novel BO algorithm referred to as max-value entropy search for multiobjective optimization with constraints (MESMOC) to solve multiobjective optimization (MOO) problems with black-box constraints that can only be evaluated through design simulations. After a full presentation of the algorithm, MESMOC is applied to a realistic ETPS design case using a heavy-duty electric vertical-takeoff-landing (eVTOL) urban aerial vehicle (UAV) power system. Two MOO experimental trials show a drastic reduction in the number of design simulations to discover a high-quality Pareto front. In Trial 1, MESMOC uncovered the entire Pareto front while only requiring to explore ~4% of the design space. With expanded design parameters and larger design space in Trial 2, a near complete but high-quality Pareto front was uncovered. Both trials compared MESMOC to the popular genetic algorithm NSGA-II and another BO algorithm predictive entropy search for multi-objective Bayesian optimization with constraints (PESMOC), showing superior performance.

Stress-Testing Framework for Urban Water Systems: A Source to Tap Approach for Stochastic Resilience Assessment

Optimizing the design and operation of an Urban Water System (UWS) faces significant challenges over its lifespan to account for the uncertainties of important stressors that arise from population growth rates, climate change factors, or shifting demand patterns. The analysis of a UWS’s performance across interdependent subsystems benefits from a multi-model approach where different designs are tested against a variety of metrics and in different times scales for each subsystem. In this work, we present a stress-testing framework for UWSs that assesses the system’s resilience, i.e., the degree to which a UWS continues to perform under progressively increasing disturbance (deviation from normal operating conditions). The framework is underpinned by a modeling chain that covers the entire water cycle, in a source-to-tap manner, coupling a water resources management model, a hydraulic water distribution model, and a water demand generation model. An additional stochastic simulation module enables the representation and modeling of uncertainty throughout the water cycle. We demonstrate the framework by “stress-testing” a synthetic UWS case study with an ensemble of scenarios whose parameters are stochastically changing within the UWS simulation timeframe and quantify the uncertainty in the estimation of the system’s resilience.

Pedagoški okvir za dizajn imerzivnog nastavnog okruženja

Virtual reality technology has a growing potential to empower and support the development of immersive teaching environments where students would have a completely different learning experience. The aim of the research is to determine the design constructs of the teaching environment with virtual reality technology, and to create a prospective pedagogical framework (system) for creating an immersive teaching environment. Using qualitative and comparative content analysis, the paper reinterpreted the existing studies dealing with various pedagogical frameworks of VR technology integration in the teaching process and then the modeling method was applied. The methodical function of the proposed pedagogical framework (system) is of an assistive character because it can be useful to practitioners in the process of contemplating about possible ways of designing immersive teaching environments within interdependent subsystems (theoretical, action, technical and subject subsystems), guided by the basic constructive elements and proposed guidelines for the design.

THE RESEARCH OF LEVELS OF DESCRIPTION OF MODERN CRITICAL APPLICATION SYSTEMS

At the current stage of economic and technical development, one of the most important problems is maintaining the reliability and fault tolerance of critical application systems used in the management of nuclear power plants, air, rail and road transport, technological units in metallurgy, the oil and gas industry, etc. The general trend of the development of critical application systems is characterized by the following factors: an increase in the degree of complexity of control objects, an expansion of the composition and level of complexity of solved functional tasks, a reduction in decision-making time, an increase in the cost of errors and the probability of large-scale emergency situations. The main reasons for the escalation of dangerous situations are failures in critical application systems. The publication examines the concept of a critical application system, examines the question of levels of description of critical application systems, examines the issue of interdependent subsystems based on the concept of potential and information technologies supporting the reliability and fault tolerance of critical application systems. For such systems (power supply and energy supply systems, water supply and drainage, etc.), an urgent problem is to ensure the objectivity, reliability and adequacy of forecasting and prevention of dangerous and possible cascading effects that can lead to man-made accidents and catastrophes. This can significantly affect the functioning, stability and survivability of systems of critical application, the ecological and technogenic safety of the surrounding territories, and the safety of life of the population of Ukraine. In the event of damage to the system of critical application, which can be sudden and intense, it will lead to an emergency situation of a man-made nature.

Gradient descent-particle swarm optimization based deep neural network predictive control of pressurized water reactor power

A pressurized water reactor (PWR) is an integrated system of various interdependent subsystems that show highly nonlinear behavior, and each component is prone to uncertainties and malfunctions that initiate potential accidents. In contrast, PWR needs to be continuously monitored for stable and safe operation over a service time. In this study, a gradient descent-particle swarm optimization hybrid algorithm-based deep neural network (GD-PSO-based DNN) approach is proposed to monitor the PWR core power and outlet temperature. The Gaussian noise is introduced to the input signal, and the PWR core stability conditions are examined by using Lyapunov analysis. The simulation results verified under different conditions, in which the proposed control approach tracks the reference inputs successfully and enhances the stability as compared with the sliding mode control, linear quadratic regulator, and proportional-integral-derivative methods. The controller is validated by using the data from RELAP5 system codes, and the performance is examined using the mean square error, integral square error, integral absolute error, integral time square error, and integral time absolute error criterion functions. This study gives the benefit to apply the GD-PSO-based DNN control method for other nuclear engineering fields for system identification, prediction, and control.

Optimal Cybersecurity Investments in Large Networks Using SIS Model: Algorithm Design

We study the problem of minimizing the (time) average security costs in large networks/systems comprising many interdependent subsystems, where the state evolution is captured by a susceptible-infected-susceptible (SIS) model. The security costs reflect security investments, economic losses and recovery costs from infections and failures following successful attacks. We show that the resulting optimization problem is nonconvex and propose a suite of algorithms – two based on convex relaxations, and the other two for finding a local minimizer, based on a reduced gradient method and sequential convex programming. Also, we provide a sufficient condition under which the convex relaxations are exact and, hence, an optimal solution of the original problem can be recovered. Numerical results are provided to validate our analytical results and to demonstrate the effectiveness of the proposed algorithms.