Design Criteria For Systems Research Articles

Enhancing shipboard waste heat management with advanced technologies

The complexity of the energy systems onboard ships, combined with the different operating/weather conditions and the availability of cutting-edge technologies, makes analyses for improving the energy and environmental performances of ships time consuming and challenging. From this point of view, this article provides new criteria for the sustainable design and management of energy systems of existing or new ships. In particular, the impact of the adoption of organic Rankine cycle units, wet steam volumetric expanders, and single or double effect absorption chillers is here investigated. Two types of ships are examined as suitable case studies, evaluating the impact of each technology and their combinations by varying the shipping cruises. By using a dynamic simulation approach, potential savings and optimal solutions are assessed for different energy system layouts by also comparing their economic, energy and environmental impact performance. Results are reported in specific performance matrices for helping stakeholders in preliminary energy efficiency analyses.In particular, outcomes show that high cooling demands of ships in the Caribbean Sea enable primary energy savings close to 4.5 %, compared to 3.5 % in the Mediterranean Sea and 3 % in the North Sea. In the latter case, cooling needs can be almost fully balanced through the examined energy recovery technologies. Screw expanders integrate best in all operating conditions with short paybacks, whilst organic Rankine cycles (with electrical efficiency above 8%) are advantageous especially in cold climate routes. Benefits on environmental impact are significant, with avoided CO2 emissions around 6 kt/y, depending on the selected ship cruise.

Navigators’ Perspective on Information Requirements for Supervisory Control of Autonomous Ships

This study explores the application of agent transparency in the context of autonomous ships. Four levels of transparency were developed depicting decisions, planned actions, reasoning, and input parameters of a collision and grounding avoidance system in a realistic navigational context. Thirty-four licensed navigators were provided with Human Machine Interface concepts depicting four levels of transparency. Qualitative feedback was obtained through semi-structured interviews about which information they felt is needed to supervise autonomous ships safely and effectively. In addition, the participants’ ranked the HMIs according to their preferences. The results indicate the need for depicting the outcomes of the system’s collision risk analysis for supervisory control. Furthermore, the results illustrate the variations in supervisory strategies and the resulting dilemma for the amount and type of information required to support supervisors. Finally, this study highlights the importance of expert knowledge in the design of safety critical systems.

Spatial analysis for water supply in seismic emergencies: the Lima-Callao metropolitan area

Introduction: In urban areas exposed to high-magnitude earthquakes, the drinking water supply would be severely damaged, and domestic services would be disrupted for a large part of the population in the event of an earthquake. The Lima-Callao metropolitan area in Peru, South America, is expected to experience an 8.8 Mw earthquake, and it is estimated that approximately 90% of the population would not have immediate access to emergency water in the case of such an event. The main objective of this paper is to define criteria for a spatial analysis method to guide the design criteria for an Emergency Water Supply System (EWaSS).Methods: This paper combines territorial, urban resilience and participatory approaches and presents the results of an interdisciplinary research with social impact. Thus, it examines the urban territory at macro-, meso- and micro scales; physical-spatial variables indicating risk levels and possible public spaces to implement the system; and socio-spatial variables regarding the population, risk perception and participation in management to strengthen urban resilience. Normative tools and the Geographic Information System are used to spatialize and systematize quantitative and qualitative information.Results and discussion: The EWaSS is an alternative for safe water supply in a post-disaster situation that would provide immediate and autonomous operation during the first 72 h of the emergency. The results show the physical-spatial and social viability of urbanized areas and the system design criteria that guide local actors in making decisions at the three levels of emergency management.

Design of novel differential power processing scheme for small-scale PV array application operating under partial shading conditions: modelling and experimental validation

In this study, an innovative approach known as Series and Parallel Differential Power Processing (SP-DPP) converters has been introduced and applied to a small-scale 2 × 2 PV array configuration. Unlike conventional methods, this approach employs Bidirectional Ćuk DC-DC Converters (BCC) in lieu of bypass diodes within serially connected PV modules, facilitating precise adjustment of module currents. Additionally, the Differential Power Processing (DPP) mechanism, utilising an Inverted-Buck Converter (IBC) topology, replaces traditional blocking diodes across parallel string connections. The paper develops mathematical models for these converters based on their transfer functions in the Continuous Conduction Mode (CCM), establishing new design criteria for SP-DPP systems. This approach ensures a well-behaved transient response and mitigates non-minimum phase response effects. Empirical testing demonstrates the efficacy of the proposed system under various static and dynamic partial shading conditions (PSCs). Furthermore, a model-based control strategy employing P + I controllers are formulated and experimentally validated to optimise the operating conditions of PV modules, enabling them to operate at their Maximum Power Points (MPPs) in varying lighting conditions. Through simulation and experimental results, the study affirms a substantial increase in the total output power of the SP-DPP system (approximately 37–41 %) compared to conventional Tied-Crossties (TCT) array configuration relying solely on bypass and blocking diodes under various static shading conditions, such as Short-Narrow (SN), Short-Wide (SW), Long-Narrow (LN) and Long-Wide (LW). Ultimately, this research highlights the novelty of the proposed SP-DPP scheme over other existing DPP schemes in the literature, in terms of maximum power extraction, cost and complexity under various lighting conditions. This research extends to explore the potential economic viability and global implications of large-scale DPP system implementation.

Stress grading system design criteria in aerospace electrical systems

Stress grading system design criteria in aerospace electrical systems

Systematic hierarchical analysis of requirements for critical systems

AbstractSafety and security are key considerations in the design of critical systems. Requirements analysis methods rely on the expertise and experience of human intervention to make critical judgements. While human judgement is essential to an analysis method, it is also important to ensure a degree of formality so that we reason about safety and security at early stages of analysis and design, rather than detect problems later. In this paper, we present a hierarchical and incremental analysis process that aims to justify the design and flow-down of derived critical requirements arising from safety hazards and security vulnerabilities identified at the system level. The safety and security analysis at each level uses STPA-style action analysis to identify hazards and vulnerabilities. At each level, we verify that the design achieves the safety or security requirements by backing the analysis with formal modelling and proof using Event-B refinement. The formal model helps to identify hazards/vulnerabilities arising from the design and how they relate to the safety accidents/security losses being considered at this level. We then re-apply the same process to each component of the design in a hierarchical manner. Thus, we use hazard and vulnerability analysis, together with refinement-based formal modelling and verification, to drive the design, replacing the system level requirements with component requirements. In doing so, we decompose critical system-level requirements down to component-level requirements, transforming them from abstract system level requirements, towards concrete solutions that we can implement correctly so that the hazards/vulnerabilities are mitigated.

Power System Design Criteria for the Service Continuity of Road Tunnels

Power System Design Criteria for the Service Continuity of Road Tunnels

Low carbon integrated vehicles and buildings

This paper defines vehicles and buildings as main sources of United Kingdom (UK) carbon dioxide (CO2) and seeks to cut such emissions using green hydrogen made from combined wind and solar energy. Combustion vehicles powered by fossil petroleum emit near half of UK climate-warming CO2 while buildings heated by natural gas provide a third. First, current UK grid problems are defined: Electricity, gas and petroleum grids. Refueling green vehicles has been a particular problem. Then experiments on the private wire community of Keele University show how green hydrogen could integrate both green vehicles and buildings. Next, the model supply chain is planned and tested. Finally, experiments and calculations are outlined, analyzing the optimum system design criteria proposed. We conclude that economic green hydrogen can displace petroleum in vehicles, while powering buildings instead of natural gas. Also, the prospect in 2024 is that profits can be made all along the green hydrogen supply chain, such that new businesses involved in local private clean communities can cost less than the National Grid monopoly and other dominant fossil energy companies.

Study of optimization design criteria for stand-alone hybrid renewable power systems

Hybrid renewable power systems integrate two or more sources of energy, one of which is renewable, optionally a storage system and typically work in stand-alone mode. They are being considered more and more and we should increment their usage taking advantage of their positive benefits: free of charge resource availability, CO2 emissions reductions and subsidies. Dealing with their inconveniences: variability of renewable resources availability and cost acquisition, through the optimization of the design and the control of the system. The optimal design of hybrid renewable power systems is usually defined by economic criteria. But there are also technical and environmental criteria to be taken into account to improve decision-making. In this paper a discussion on different criteria will introduce the non-economical perspectives in addition to the economic criteria. A case study of a PV-Wind-Diesel-Battery system for a Telecommunication station in Catalonia is discussed. Availability of renewable energy sources is obtained with RETScreen and PVSyst. Analysis and simulations of various hybrid power systems have been done in HOMER resulting on a comparison of different scenarios. Optimal scenario taking into account the best results of all three types of criteria: economic, technical and environmental, is a trade-off of the economic optimum.

Evaluating Transient Drawdown and Slope Stabilization from Horizontal Drain Installation

Elevated groundwater levels drive slope instability through decreased effective stresses and frictional strength. Consequently, landslide mitigation often relies on a variety of stabilizing techniques, often including dewatering and drainage as a primary control on stability. One of the most effective dewatering techniques for landslides are horizontal drain systems, which consist of arrays of perforated pipes drilled into hillslopes for gravity-driven removal of groundwater. One of the few economical solutions for large-magnitude, groundwater-driven landslides, horizontal drain arrays facilitate groundwater drawdown through gravity-driven flow, consequently increasing effective stress and slope stability within its domain of influence. However, design of horizontal drain systems remain largely observational and there is limited insight towards the transient performance of these drainage systems. This study aims to explore relevant theoretical design criteria for horizontal drain systems and their relative importance as related to drawdown mechanism and magnitude, as well as slope stability.

Internet of things and cloud based smart parking system design criteria

In urban areas, traffic density is seen due to the congested residential areas and the high number of vehicles. The problem of drivers searching for parking spaces in central areas creates traffic. The Internet of Things (IoT) technology offers important solutions with its networking feature to solve problems such as traffic congestion, road safety and inefficient use of parking areas, which are waiting for solutions within the scope of Intelligent Transportation Systems. In this study, the technological infrastructures used by IoT-based smart parking systems are examined and integrated building models are proposed for system designs where parking lots are managed. For smart park design, devices, networks and cloud architecture used in IoT-based systems were examined and requirements were determined. The criteria of an application based on design central management are given. The criteria of an application based on design center management are given. Thanks to the smart parking system to be created in the light of these criteria, the closest parking area will be determined. These designed IoT-based systems will contribute to the reduction of traffic congestion, loss of time in full parking areas, air pollution caused by stop and start vehicles, and fuel savings in the economic field.

An improved solution methodology for the urban transit routing problem

An improved solution methodology is proposed in this paper for the urban transit routing problem (UTRP). This methodology includes a procedure for the generation of improved initial solutions as well as improved metaheuristic search approaches, involving the use of hyperheuristics to manage search operators in both trajectory-based and population-based metaheuristics. The UTRP variant considered in this paper is that of deciding upon efficient bus transit routes. The design criteria embedded in our UTRP model are the simultaneous minimisation of the expected average passenger travel time and minimisation of the system operator’s cost (measuring the latter as the sum total of all route lengths in the system). The model takes as input an origin–destination demand matrix for a pre-specified set of bus stops, along with an underlying road network structure, and returns as output a set of bus route trade-off solutions. The decision maker can then select one of these route sets subjectively, based on the desired degree of trade-off between the aforementioned transit system design criteria. This bi-objective minimisation problem is solved approximately in three distinct stages — a solution initialisation stage, an intermediate analysis stage, and an iterative metaheuristic search stage during which high-quality trade-off solutions are sought. A novel procedure is introduced for the solution initialisation stage, aimed at effectively generating high-quality initial feasible solutions. Two metaheuristics are implemented to solve instances of the problem, namely a dominance-based multi-objective simulated annealing algorithm and an improved non-dominated sorting genetic algorithm, each equipped with a hyperheuristic capable of managing the perturbation operators employed. Various novel operators are proposed for these metaheuristics, of which the most noteworthy take into account the demand of passengers.

ADEPT 2022 workshop: a summary of strengths and weaknesses of the AADL ecosystem

The Architecture Analysis and Design Language (AADL) is a SAE Standard for the modeling of both the hardware and the software of embedded systems. The AADL standard is now mature and is today employed by numerous stakeholders in the domain of critical embedded real-time systems to address a large set of concerns: performances (latency, schedulability), safety, or security, ... The ADEPT workshop aims to present and report on current projects in the field of design, implementation, and verification of critical systems where AADL is a first-citizen technology. This article is a summary of the ADEPT 2022 workshop.

Intelligent nanomaterials for cancer therapy: recent progresses and future possibilities.

Intelligent nanomedicine is currently one of themost active frontiers in cancer therapy development. Empowered by the recent progresses of nanobiotechnology, a new generation of multifunctional nanotherapeutics and imaging platforms has remarkably improved our capability to cope with the highly heterogeneous and complicated nature of cancer. With rationally designed multifunctionality and programmable assembly of functional subunits, the invivo behaviors of intelligent nanosystems have become increasingly tunable, making them more efficient in performing sophisticated actions in physiological and pathological microenvironments. In recent years, intelligent nanomaterial-based theranostic platforms have showed great potential in tumor-targeted delivery, biological barrier circumvention, multi-responsive tumor sensing and drug release, as well as convergence with precise medication approaches such as personalized tumor vaccines. On the other hand, the increasing system complexity of anti-cancer nanomedicines also pose significant challenges in characterization, monitoring and clinical use, requesting a more comprehensive and dynamic understanding of nano-bio interactions. This review aims to briefly summarize the recent progresses achieved by intelligent nanomaterials in tumor-targeted drug delivery, tumor immunotherapy and temporospatially specific tumor imaging, as well as important advances of our knowledge on their interaction with biological systems. In the perspective of clinical translation, we have further discussed the major possibilities provided by disease-oriented development of anti-cancer nanomaterials, highlighting the critical importance clinically-oriented system design.

Exploring Performance and Cost Trade-Offs in Electrochemical CO2 Separation Processes

Increasing global energy demand coupled with a continued reliance on carbon-intensive fuels has contributed to the rise in anthropogenic greenhouse gas emissions that are adversely impacting the global climate.1,2 While the expansion of low-cost renewable electricity (often coupled with energy storage) offsets fossil-fuel-based generation, complete mitigation of carbon emissions will likely require the capture, utilization, and/or storage of carbon dioxide (CO2) at scale. Today’s state-of-the-art separation technologies rely on thermochemical processes to extract CO2 from industrial waste streams, post-combustion flue gases, or directly from the atmosphere. Such approaches are energetically intensive and typically rely on fossil-fuel-derived heat to release CO2 and regenerate the sorbent, ultimately limiting process effectiveness.3 Electrochemical approaches to CO2 capture and concentration are increasingly seen as a viable pathway to reducing carbon emissions, as these processes enable several advantages including direct integration with renewables, modular deployment, operation near ambient conditions, and high energetic efficiencies.4 Despite this promise, these concepts are at an early-stage and the relationships between cost and performance are not well-understood at the molecular-, cell-, or system-level.In this presentation, we will discuss how techno-economic modeling can be used to inform design criteria for cost-competitive electrochemical CO2 separation systems. We will specifically focus on a 4-stage system with soluble redox-active species for direct binding / debinding with CO2. First, we describe and integrate all process units (i.e., electrochemical reactor, absorber, desorber) via thermodynamic, chemical, and electrochemical relationships and then estimate capital, fixed, and variable costs via a levelized cost of capture model. Second, we investigate key scaling correlations and cost sensitivities for the 4-stage system, including the role of resistive losses in the electrochemical reactor and binding affinity in the absorption column. Third and finally, we connect system-level performance and cost targets to molecular / system properties and operating envelopes. While our focus is on a particular system, the framework is generalizable and can be extended to different electrochemical and thermochemical approaches to CO2 separation, potentially enabling technology comparisons on a common basis. Acknowledgements This work was supported by the Alfred P. Sloan Foundation. K.M.R. gratefully acknowledges the support of the National Defense Science and Engineering Graduate (NDSEG) Fellowship. References Ritchie, H., Roser, M. & Rosado, P. CO2 and Greenhouse Gas Emissions. Our World in Data (2020). Annual Energy Outlook 2021. U.S. Energy Information Administration (2021).Khan, F. M., Krishnamoorthi, V. & Mahmud, T. Modelling reactive absorption of CO2 in packed columns for post-combustion carbon capture applications. Chemical Engineering Research and Design 89, 9, 1600–1608 (2011).Renfrew, S. E., Starr, D. E. & Strasser, P. Electrochemical Approaches toward CO2 Capture and Concentration. ACS Catal. 10, 21, 13058–13074 (2020).

Study of Continuous Simulation Supporting Multiple Design Criteria for Sustainable Drainage Systems

Study of Continuous Simulation Supporting Multiple Design Criteria for Sustainable Drainage Systems

New ventilation design criteria for energy sustainability and indoor air quality in a post Covid-19 scenario

The Covid-19 outbreak raised great attention to the importance of indoor air quality in buildings. Even if the Covid-19 epidemic is nearing an end, all stakeholders agree that increasing outside air flow rates is beneficial for decreasing the likelihood of contagion, lowering the risk of future pandemics, and enhancing the general safety of the interior environment. Indeed, diverse concerns raised about whether the ventilation standards in place are still adequate. In this context, this research intends to assess the suitability of current ventilation standards in addressing the current pandemic scenario and to offer novel criteria and guidelines for the design and operation of HVAC systems, as well as useful guidance for the creation of future ventilation standards in a post-Covid-19 scenario. To that end, a comprehensive analysis of the ANSI/ASHRAE 62.1 is carried out, with an emphasis on its effectiveness in reducing the risk of infection. Furthermore, the efficacy of various ventilation strategies in reducing the likelihood of contagion has been investigated. Finally, because building ventilation is inextricably linked to energy consumption, the energy and economic implications of the proposed enhancements have been assessed. To carry out the described analysis, a novel method was developed that combines Building Energy Modelling (BEM) and virus contagion risk assessment. The analyses conducted produced interesting insights and criteria for ventilation system design and operation, as well as recommendations for the development of future standards.

Individuals Utilization Behavior While Using Critical Healthcare Systems (Medical Ventilator)

Ergonomics and human factors play an important role in interaction design. Poor usabil-ity design of critical safety systems can easily lead to human error. While inspecting the critical systems, there are vital factors that have to be considered, such as demographic, organizational, interface design, and task factors. This study has inspected the influence of different demographic factors (age, gender, and education) on the medical ventilator system's usability. The primary purpose is to seek the difference in task completion time, reflection time, and the number of touches during the interaction, considering different demographic factors. As well as to seek the difference in perceived task workload in-dex. To test the study hypothesis, the Hamilton-c6 ventilator prototype was developed. The experiments were conducted on 54 participants, including physicians and nurses, in a controlled environment from different public-private sector hospitals in Pakistan. De-scriptive statistics and ANOVA were used to assess the study objectives. The results suggest significant differences between male vs. female and physician's vs. nurses groups while interacting with safety-critical systems. However, the difference between young and older adults was not significant. These findings have substantial implications for the effective user-centric design of safety-critical systems.

Stability assessment and development of design criteria for SCBF systems with in‐plane buckling braces

AbstractSpecial concentrically braced frames (SCBFs) with in‐plane buckling (IPB) braces are often designed using the provisions applicable for out‐of‐plane buckling (OOPB) brace systems. As a result, the IPB brace systems may fail in the undesirable modes as observed in past experimental studies. In this study, a novel simplified analytical formulation based on the rigid beam spring model (RBSM) has been proposed to prevent the out‐of‐plane buckling of IPB braces. A high‐fidelity finite element model (FEM) is generated and validated with the experimental studies incorporating the influence of the residual stress, imperfection, and strain hardening. The variability, sensitivity, and uncertainties involved in predicting the direction of buckling of braces are examined. A parametric study has been carried out to investigate the influence of thickness and clearance of the gusset and knife plates, geometric imperfections, slenderness ratios, compactness ratios, residual stresses, and frame actions considering the most destabilizing effect in the OOPB mode. The third mode of buckling, termed as the mixed‐mode of buckling, has been observed in this study. A design criterion is proposed to get the desired IPB mode of buckling of braces in SCBFs. Multivariate regression analysis is carried out to incorporate the impact of various parameters as well as uncertainties in the formulation of the design criteria. The validity of the proposed equation is verified by comparing the findings of past experimental studies for various loading scenarios. Finally, a resistance factor of 0.8 in the LRFD approach has been proposed for the IPB brace systems.

Formal domain-driven system development in Event-B: Application to interactive critical systems

The design of complex and/or critical systems requires handling the environment constraints in which these systems evolve. Formal methods allow system developers to design models of such systems. They provide constructs for modelling components and views of these systems. However, these formal methods do not include built-in constructs for modelling the environment, and more broadly, domain knowledge associated with system models. Although ontologies have demonstrated their efficiency in modelling domain-specific features, they are not available as built-in constructs in formal methods.This paper shows how formal ontologies can be used to model domain-specific knowledge, as well as how system models may refer to these ontologies through annotation. We rely on the Event-B refinement and proof state-based method, and the associated theories, to define a framework in which domain-specific knowledge ontologies are formalised as Event-B theories defining data types used to type Event-B system design models. Finally, this framework is deployed for the specific case of interactive critical systems. To illustrate the proposed approach, a case study of the Traffic Collision Avoidance System (TCAS) is developed.