System Design Perspective Research Articles

A Bulk versus Nanoscale Hydrogen Storage Paradox Revealed by Material‐System Co‐Design

AbstractMetal hydrides are serious contenders for materials‐based hydrogen storage to overcome constraints associated with compressed or liquefied H2. Their ultimate performance is usually evaluated using intrinsic material properties without considering a systems design perspective. An illustrative case with startling implications is (LiNH2+2LiH). Using models that simulate the storage system and associated fuel cell of a light‐duty vehicle (LDV), the performance of the bulk hydrides is compared with a nanoscaled version in porous carbon (PC), (LiNH2+2LiH)@(6‐nm PC). Using experimental material properties, the simulations show that (LiNH2+2LiH)@(6‐nm PC) counterintuitively has higher usable gravimetric and volumetric capacities than the bulk counterpart on a system basis despite having lower capacities on a materials‐only basis. Nanoscaling increases the thermal conductivity and lowers the desorption enthalpy, which consequently increases heat management efficiency. In a simulated drive cycle for fuel cell‐powered LDV, the fuel cell is inoperable using bulk (LiNH2+2LiH) as the storage material but completes the drive cycle using the nanoscale material. These results challenge the notion that nanoscaling incurs mass and volume penalties. Instead, the synergistic nanoporous host‐hydride interaction can favorably modulate chemical and heat transfer properties. Moreover, a co‐design approach considering application‐specific tradeoffs is essential to accurately assess a material's potential for real‐world hydrogen storage.

A System Design Perspective for Business Growth in a Crowdsourced Data Labeling Practice

A System Design Perspective for Business Growth in a Crowdsourced Data Labeling Practice

Characterization of Doppler shift in inter-satellite laser link between LEO, MEO, and GEO orbits

Over the past few decades, the development of optical wireless communications (OWC) has led to its application in a wide range of environments, including indoor, outdoor, and space. Optical carriers offer advantages such as high bandwidth, security, and directivity, making it a suitable technology for applications in radio astronomy, remote sensing, cellular networks, high-speed train communications, last-mile access, underwater/terrestrial communications, and satellite communications employing laser links. However, laser links between satellites experience Doppler shift due to their relative motion, and this effect should be taken into account from a system design perspective. This paper presents a study of the Doppler shift characterization in laser links for circular Keplerian orbits. An analytical derivation establishes the relationship between the Keplerian orbital elements and the Doppler shift in laser links. The derived equations provide a more comprehensive understanding of the impact of these orbital elements on the Doppler shift in laser links. Additionally, equations have been derived for the Doppler shift rate and the visibility window condition during satellite communication. Furthermore, we conducted a link failure analysis using simulations to evaluate the effects of the Doppler shift, also identifying the worst-case scenarios for orbits most significantly impacted by this shift. The results showed that among the six Keplerian orbital elements, the semi-major axis, inclination, and right ascension of ascending node contribute to the Doppler shift in circular orbits. While the Doppler shift impact is less significant for laser communication systems employing intensity modulation/direct detection, it can degrade the communication system performance for coherent detection. This work contributes to the effective estimation of Doppler shift from a system design perspective.

Experimental validation of the theoretical ejector model in a low-grade waste heat refrigeration system using R1233zdE as a working fluid

Rising electricity prices and environmental regulations make it increasingly economically justifiable to utilize low-temperature waste heat, generated as a by-product of many technological processes. One potential application is the conversion of heat into cooling capacity using an ejector refrigeration system, to replace conventional electric-consuming cooling systems. Such systems, despite numerous descriptions in the literature, have not found industrial applications up to date. This work presents experimental results on the first commercial prototype cooling system driven by 200 kW waste heat of ultra-low temperature between 60 °C and 70 °C coming from the oil system of air compressors operating under real industrial operating conditions. A refrigeration system configuration based on the use of heat recovery downstream of the ejector and splitting the waste heat recovery heat exchanger into two stages was applied. The low GWP and low-pressure HFO R1233zd(E) refrigerant was used as a working fluid. The high-temperature cooling parameters, equivalent to the glycol temperature of 16 °C/19 °C (outlet/inlet of the evaporator), were examined and the COP of 0,25 was obtained. To obtain such a promising COP value, the critical and subcritical parameters of the ejector were investigated. Based on the experimental results the validation of the ejector theoretical model was performed for low-pressure refrigerant. The ejector component characteristic efficiencies were optimized for the ejector calculation model, and ejector key performance parameters were estimated to a high accuracy. The average relative error in the estimation was 7.1%, 4.5%, and 13.7% for the mass entrainment ratio, pressure ratio and ejector total efficiency, respectively. The resulting accuracy is sufficient from the perspective of refrigeration system design.

Semiparallel Service Systems in CPSS: Theory and Application

In this article, we study the design and innovation of smarter service systems considering the deep integration of real service systems and virtual service elements. Specifically, we consider the perspective of life-cycle service system design and innovation that must consider the “social space” factors, such as stakeholders’ behaviors, which increases the complexity of service cyber–physical–social systems (CPSSs). We propose a new methodology framework, the semiparallel service system (SPSS) framework, following the CPSS architecture and artificial societies, computational experiments, and parallel execution (ACP) methodologies emerging in complex system modeling. We design two decomposition-then-aggregation loops to reduce the complexity of service systems innovation. In the first loop, we expand the Vee model of systems engineering to the N model to show how to develop an innovative service system step by step. In the second loop, the SPSS, in which the hybrid service system is parallel with the real service system, maintains the continuous innovations of the system. Following our framework, we can design prototypes, perform experiments, and run the hybrid service system. We use two cases, an Internet hospital platform design and a new service design in a customs bonded warehouse, to demonstrate the advantages and potential of our proposed methodology. Finally, we discuss the future research challenges and directions.

Review of Engineering Controls for Indoor Air Quality: A Systems Design Perspective

This paper aims to review the engineering controls for indoor air quality (IAQ) from a systems design perspective. As a result of the review, we classify the literature content into three categories: (1) indoor air treatments, (2) dissemination control strategies, and (3) information technology. Indoor air treatments can be generally interpreted as the “cleaning” aspect, which covers ventilation and contaminant removal techniques. Dissemination control focuses on how contaminants generated in an indoor space can be transmitted, where four types of dissemination are classified. The category of information technology discusses IAQ sensors for monitoring, as well as the applications of the Internet of Things and IAQ data. Then, we further analyze the reviewed engineering controls by performing systems and functional analysis. Along with a discussion of IAQ functions, we suggest some systems design techniques, such as functional decoupling and design for flexibility/resilience, which are expected to promote more systems thinking in designing IAQ solutions.

Exploring the User Acceptance of Online Interactive Mechanisms for Live-Streamed Teaching in Higher Education Institutions

With the advancement of technology and the development of society, live-streamed teaching, characterized by real-time interaction between teachers and students, has emerged as a new form of online education and has rapidly evolved in practice. However, in online live-streamed teaching, there are still various issues, such as insufficient teacher–student interaction and interactive functionalities, that fail to meet learners’ needs. These issues impact the efficiency and user experience of online live-streamed teaching. Currently, scholars mostly examine these issues from the perspective of online teaching system design, paying less attention to exploring the interactive mechanisms from the point of view of user perception. Within the context of Chinese education, based on the technology acceptance model, this study investigated student personality traits, interactive motivations, and platform interactive functionalities, and the aim of this study was to explore the influencing factors and mechanisms of online live-streamed teaching interactions. A total of 281 university students participated in the survey, and the results indicated that the platform’s interactive functionalities significantly and positively predicted perceived usability and perceived ease of use. Moreover, the students’ personality traits significantly and positively predicted interaction motivations and usage attitudes. Furthermore, usage attitudes significantly and positively predicted interactive behavior. A mediation analysis revealed that perceived usability and perceived ease of use mediated the relationship between the platform’s interactive functionalities and usage attitudes. Additionally, interaction motivations mediated the relationship between the students’ personality traits and interactive behavior. We discuss the potential implications and practical significance of the current research findings. The results of this study offer viable strategies for enhancing current online educational practices, aiding educational designers in order to better organize and promote online educational interactions to elevate student engagement and advance the sustainable development of digital education.

Model predictive temperature control of a closed-loop spray cooling system

A dynamic model of a closed-loop spray cooling system was proposed, and a model predictive temperature control algorithm was presented. The presented algorithm could quantitively estimate sudden changes in heat load, and then plan an optimized control path along which the temperature trajectory was numerically predicted to be the most stable. Then, the presented algorithm was integrated into a closed-loop spray cooling system, and its control performance was numerically studied. The results showed that, following a 20 W downward step change in heat load, the temperature was re-stabilized in 4 s, with its oscillation less than 0.14 K. Under identical conditions, the presented algorithm outperformed PID in terms of temperature stability, with its peak time shorter by 25–55%, settling time shorter by 38–51%, and average temperature offset smaller by 50–60%. This advantage was mainly because the presented algorithm compensated for hydraulic and thermal lags, two sources of control nonlinearity, by excessive regulation in advance. Unexpectedly, temperature overshoots of the presented algorithm and PID did not differ significantly, seemingly due to the algorithm-inherent estimation lag. From a system design perspective, the length of pump pipeline should be as short as possible, which proved to help reduce overshoot and settling time. Similarly, addition in heat load’s mass also helped reduce overshoot, but would result in an unfavorable long settling time, and vice versa. The simulation results were validated by experimental data, with error less than 10%.

Diagnosis-based domain-adaptive design using designable data augmentation and Bayesian transfer learning: Target design estimation and validation

Research on prognosis and health management (PHM) technology is actively being conducted. Existing diagnostic technologies focus on qualitative results, i.e., anomaly detection and classification for maintenance. Therefore, quantified diagnostic solutions are required to allow users to take clear actions in advance. In this paper, we propose a diagnostic design solution methodology from a system design perspective, considering the degradation and uncertainty of the system via combined data-driven and model-based approaches using domain adaptation and designable data augmentation. When designing a new target system similar to an existing developed source system, the uncertainty of the diagnostic knowledge of the existing source system is quantified to adapt the domain knowledge to the new target system through Bayesian transfer learning. Additionally, with small amount of target data, a deep-learning-based design algorithm is used to estimate the system design solutions. To validate the proposed method, a case study was conducted using mathematical and Modelica-based physical system models. We verified that the system response obtained from the estimated design solution is more likely to belong to the normal class than to the initial design.

Human-in-the-loop for computer vision assurance: A survey

Human-in-the-loop (HITL), a key branch of Human–Computer Interaction (HCI), is increasingly proposed in the research literature as a key assurance method for automated analyses and predictive application designs. As the need increases to improve methods in Artificial Intelligence (AI) model training, optimize systems performance, provide AI explainability, and monitor AI system operations, the concept of HITL is gaining traction due to its value in solving these challenges. This survey of existing works on HITL from a computer vision system design perspective focuses on the following AI assurance principles: (1) improved data assurance, such as data preparation or automated data labeling; (2) algorithmic assurance, such as managing uncertainty and AI trustworthiness; and (3) critical limitations and capabilities introduced by HITL into a system’s operational efficiency. We survey prior work within these foci, including technical strengths and weaknesses of novel approaches and ongoing research. This review of the state of the art in HITL computer vision research supports an informed discussion of considerations and future opportunities in this critical space.

COVID-19 pandemic: ethical issues and recommendations for emergency triage.

The current epidemic of Coronavirus Disease 2019 (COVID-19) has become a public health event worldwide. Through ethical analysis of a series of epidemic prevention phenomena and epidemic prevention measures taken by the Chinese (and other countries) government and medical institutions during the COVID-19 pandemic, this paper discusses a series of ethical difficulties in hospital emergency triage caused by the COVID-19, including the autonomy limitation of patients and waste of epidemic prevention resources due to over-triage, the safety problem of patients because of inaccurate feedback information from intelligent epidemic prevention technology, and conflicts between individual interests of patients and public interests due to the "strict" implementation of the pandemic prevention and control system. In addition, we also discuss the solution path and strategy of these ethical issues from the perspective of system design and implementation based on the Care Ethics theory.

An Ostensive Information Architecture to Enhance Semantic Interoperability for Healthcare Information Systems

Semantic interoperability establishes intercommunications and enables data sharing across disparate systems. In this study, we propose an ostensive information architecture for healthcare information systems to decrease ambiguity caused by using signs in different contexts for different purposes. The ostensive information architecture adopts a consensus-based approach initiated from the perspective of information systems re-design and can be applied to other domains where information exchange is required between heterogeneous systems. Driven by the issues in FHIR (Fast Health Interoperability Resources) implementation, an ostensive approach that supplements the current lexical approach in semantic exchange is proposed. A Semantic Engine with an FHIR knowledge graph as the core is constructed using Neo4j to provide semantic interpretation and examples. The MIMIC III (Medical Information Mart for Intensive Care) datasets and diabetes datasets have been employed to demonstrate the effectiveness of the proposed information architecture. We further discuss the benefits of the separation of semantic interpretation and data storage from the perspective of information system design, and the semantic reasoning towards patient-centric care underpinned by the Semantic Engine.

Design Specifications of Augmentative and Alternative Communication Apps for Individuals with Autism Spectrum Disorder

The literature has emphasized the positive impact of mobile technologies with augmentative and alternative communication (AAC) apps for enhancing the functional communication skills of individuals with autism spectrum disorders (ASD). Although various AAC apps are available, the system design of such apps presents assorted challenges, particularly for those with ASD in different cultures. Designing useful and engaging apps by considering the affordances of mobile technologies and the characteristics of individuals with ASD may contribute to the success of interventions. In this regard, the purpose of this study is to examine the design specifications of AAC apps based on the considerations of subject-matter experts from an instructional system design (ISD) perspective. The current research employed a design-based research framework, including different methods. An AAC app named as EBA was developed by following design specifications as suggested by the field experts to answer the research questions. The results of the study revealed several enhancements in usability, flexibility, and feasibility issues of AAC apps, and highlighted the importance of (a) personalized apps, (b) simple user-interface, (c) hierarchical representation of visuals, (d) responsive apps, (e) help and documentation, and (f) parent control service. Directions for future research are proposed.

A Comparative Study on Poverty Reduction Models of Rural Collective Economic Organizations from the Perspective of Relative Poverty

Rural collective economic organization is an important guarantee to develop rural collective economy and increase farmers' income. In order to further explore its future development ideas and improve the development mechanism, this paper conducts a comparative study on the two poverty reduction models of Toupu Town and Liyuan Village. From the overall perspective, they reflect the realistic requirements of returning public services to the rural grass-roots level in the perspective of relative poverty, as well as the positive efforts made by local Party committees and governments to achieve rural revitalization. From the perspective of system design, Toupu Town and Liyuan Village show different development ideas and specific designs. The "political economic integration" route of Liyuan Village is reasonable and effective, while the "political economic separation" route of Toupu Town presents a crisis of trust. We put forward specific ideas on how to improve and amend the poverty reduction model of Liyuan and Toupu.

Quantitative Analysis of Extracellular Vesicle Uptake and Fusion with Recipient Cells.

In precision medicine, extracellular vesicles (EVs) are promising intracellular drug delivery vehicles. The development of a quantitative analysis approach will provide valuable information from the perspective of cell biology and system design for drug delivery. Previous studies have reported quantitative methods to analyze the relative uptake or fusion of EVs to recipient cells. However, relatively few methods have enabled the simultaneous evaluation of the "number" of EVs taken up by recipient cells and those that fuse with cellular membranes. In this study, we report a simple quantitative method based on the NanoBiT system to quantify the uptake and fusion of small and large EVs (sEVs and lEVs, respectively). We assessed the abundance of these two subtypes of EVs and determined that lEVs may be more effective vehicles for transporting cargo to recipient cells. The results also indicated that both sEVs and lEVs have very low fusogenic activity, which can be improved in the presence of a fusogenic protein.

Compensating for part arrival uncertainties in two-processing-machine, one-buffer flow lines: Inventory flexibility design based on the system transient performances

• A structured Markov process model for the proposed flow lines;. • Transition equation derivation for the flow lines;. • The algorithms for factoring a class of states to derive closed-form expressions;. • System transient performance analysis of the flow lines system;. • Discrete event dynamic system simulation and verification. In one-of-a-kind production (OKP), a flow line with two distinct deterministic processing time machines and one “flexible” storage buffer is studied from the perspective of manufacturing system design and transient behaviour analysis. This manufacturing process is disrupted by part arrival uncertainties and is considered a discrete dynamic stochastic system. The dynamic behaviour of the flow line is structured as a transfer line with multi-state machines and finite-storage buffers by a discrete-time, discrete-state Markov chain for the transient performance analysis, optimal design and efficient production operation. To assess the dynamic disruptions and further limit the cascading effects on the flow line, in the presented analytical model, the studies quantify the evolution of a basic serial production process over time; and meanwhile, we evaluate and optimize the manufacturing system transient performance to determine the optimal design of inventory flexibility as a function of the time and states. By factoring out a class of appropriate transient states associated with an initial state at a certain time slot and deriving closed-form expressions using the transition equations, we sought to determine the transient probabilities of the manufacturing system states to establish relationships between the variable system parameters and the performance measures. By embedding these practical results with quantitative precision in an optimal design process of inventory flexibility, we consider setting the storage buffer level between two processing machines for refined production optimization and control when the part arrival uncertainties and lack of synchronization constantly occur in this serial manufacturing system.

Playing it safe: A literature review and research agenda on motivational technologies in transportation safety

While motivation affects safety-related decision-making and human reliability, technologies to promote it are scarcely used. We have only recently witnessed how motivational technologies, including serious games, gamification, and persuasive technologies have emerged on the palette of methods for enhancing transportation safety. However, the research on these technologies for transportation safety is fragmented, preventing future studies and practical efforts. This paper describes the state-of-the-art through a systematic review to address this issue. Analyzing 62 studies, we perceive that motivational technologies focus on reducing the accident likelihood and mitigating their consequences. While these technologies can induce positive psychological change and improve learning, the evidence of behavioral change is mainly limited to simulation settings, lacking examination of the long-term benefits and potential adverse effects. Our results highlight the importance of aligning motivational design with the cognitive demand of the transportation task and the means for improving safety. Future research should explore how motivational technologies can enhance safety from the system design perspective, cover a broader scope of transportation modes, compare their effects to conventional approaches while considering social aspects in their design and evaluation. Beside providing an overview of the area and future directions, this paper also introduces design recommendations to guide practitioners.

Effect of Progressive Integration of On-Board Systems Design Discipline in an MDA Framework for Aircraft Design with Different Level of Systems Electrification

The on-board design discipline is sometimes ignored during the first aircraft design iterations. It might be understandable when a single on-board system architecture is considered, especially when a conventional architecture is selected. However, seeing the trend towards systems electrification, multiple architectures can be defined and each one should be evaluated during the first tradeoff studies. In this way, the systems design discipline should be integrated from the first design iterations. This paper deals with a progressive integration of the discipline to examine the partial or total effect of the systems design inside an MDA workflow. The study is carried out from a systems design perspective, analyzing the effect of electrification on aircraft design, with different MDA workflow arrangements. Starting from a non-iterative systems design, other disciplines such as aircraft performance, engine design, and aircraft synthesis are gradually added, increasing the sensibility of the aircraft design to the different systems architectures. The results show an error of 40% in on-board systems assessment when the discipline is not fully integrated. Finally, using the workflow which allows for greater integration, interesting differences can be noted when comparing systems with different levels of electrification. A possible mass saving of 2.6% of aircraft MTOM can be reached by properly selecting the systems technologies used.

A method for identifying marine targets based on mining of multi-characteristic movement patterns

Currently, marine ship targets are often identified directly through sensing targets. As a result, the potential value of massive spatiotemporal data has not been fully utilized. Because relevant maritime authorities have new requirements for understanding the situation of naval traffic flows and target identity behavior, obtaining necessary information about maritime targets at the data level and further understanding the ship movement patterns at the characteristic level are the focus of the current study. From the perspective of system design, this study proposes a method for obtaining a number of feature sets by mining the ship trajectory data and then identifying unknown targets. In the process of constructing the multi-characteristic sets, this study focuses on the importance of the distribution characteristics of ship channels for target identification. This study proposes an improved similarity measure—a trajectory rasterization model method. Experimental verification based on the measured data set shows that the system design can successfully fulfill the requirements for the identification of unknown targets and has a certain universality.

Analyzing and Visualizing Learning Data: A System Designer's Perspective

In this work, we consider learning analytics for primary and secondary schools from the perspective of the designer of a learning system. We provide an overview of practically useful analytics techniques with descriptions of their applications and specific illustrations. We highlight data biases and caveats that complicate the analysis and its interpretation. Although we intentionally focus on techniques for internal use by designers, many of these techniques may inspire the development of dashboards for teachers or students. We also identify the consequences and challenges for research.