Coordination Requirements Research Articles

Mechanical Property of Thermoplastic Polyurethane Vascular Stents Fabricated by Fused Filament Fabrication

Vascular stents have many applications in treating arterial stenosis and other vascular-related diseases. The ideal vascular stent for clinical application should have radial support and axial bending mechanical properties that meet the requirements of vascular deformation coordination. The materials used for vascular stents implanted in the human body should have corresponding biocompatibility to ensure that the stents do not cause coagulation, hemolysis, and other reactions in the blood. This study fabricated four types of vascular stents, including inner hexagon, arrowhead, quadrilateral, and outer hexagonal, using fused filament fabrication technology and thermoplastic polyurethane (TPU) as materials. By evaluating the effects of edge width and wall thickness on the radial support and axial bending performance, it was found that the inner hexagonal stent exhibited the best radial support and axial bending performance under the same conditions. The design and fabrication of vascular stents based on 3D printing technology have promising application prospects in personalized customized vascular repair therapy.

Bridging the reality gap in drone swarm development through mixed reality

AbstractSwarm algorithms promise to solve certain problems in large multi-robot systems. The evaluation of large swarms is however challenging as simulations alone often lack some properties of real systems whereas real-world experiments are costly and complex. We present a mixed reality (MR) system that connects simulated and physical robots though a 5G network, facilitating MR experiments to evaluate communication-based swarm algorithms. The effectiveness of the system is demonstrated through extensive experiments with unmanned aerial vehicles. Measurements show that the communication requirements of swarm coordination are well met by 5G but the computing power of the simulation server can be a bottleneck. However, even when the simulation slows down, communication and coordination take place in real time. In conclusion, 5G-enabled MR experiments are a feasible tool for bridging the reality gap in the development and evaluation of robot swarms.

Levels of Unrelated Diversification and Firm Performance: A Conceptual Description of an S-Shaped Hypothesis

This study reconceptualizes the so far inconclusive relationship between unrelated diversification and financial performance by explaining how coordination costs can shape the amount of free cash flow and related agency problems at different levels of unrelated diversification. The study builds upon the notion that coordination requirements and associated coordination costs will vary at levels of unrelated diversification to regulate the amount of free cash flow managers will have at their disposal at each level of unrelated diversification. Based on the agency costs associated with free cash flow, we conceptualize that at different stages of unrelated diversification, the degree of managerial misuse of free cash flow can create different performance implications of the unrelated diversified firm to explain a proposed S-shaped relationship.

Fetal endocrine axes mRNA expression levels are related to sex and intrauterine position

BackgroundThe hypothalamic–pituitary–adrenal (HPA) and -gonadal (HPG) axes are two major pathways that connect the neural and endocrine systems in vertebrates. Factors such as prenatal stress and maternal exposure to exogenous steroids have been shown to affect these pathways during fetal development. Another less studied factor is the transfer of hormones across fetuses in multifetal pregnancies. This form of transfer has been shown to influence the morphology, anatomy, physiology, and behavior of the offspring in litter-bearing mammals, an influence termed the intrauterine position (IUP) effect. In this study, we sought to delineate how the IUP effects HPA and HPG brain receptors, peptides, and enzymes (hereafter components) in utero and how these influences may differ between males and females.MethodsWe utilized the unconventional model of culled free-ranging nutria (Myocastor coypus), with its large natural variation. We collected brain tissues from nutria fetuses and quantified the expression of key HPA and HPG components in three brain regions: prefrontal cortex, hypothalamus, and striatum.ResultsWe found an interaction between sex and IUP in the mineralocorticoid receptor (MR), gonadotropin-releasing hormone receptor (GNRHR), androgen receptor (AR), and estrogen receptor alpha (ESR1). IUP was significant in both gonadotropin-releasing hormone (GnRH) and its receptor GNRHR, but in different ways. In the hypothalamus, fetuses adjacent to same-sex neighbors had higher expression of GnRH than fetuses neighboring the opposite sex. Conversely, in the cortex, GNRHR exhibited the inverse pattern, and fetuses that were neighboring the opposite sex had higher expression levels than those neighboring the same sex. Regardless of IUP, in most components that showed significant sex differences, female fetuses had higher mRNA expression levels than male fetuses. We also found that HPA and HPG components were highly related in the early stages of gestation, and that there was an interaction between sex and developmental stage. In the early stages of pregnancy, female component expression levels were more correlated than males’, but in the last trimester of pregnancy, male components were more related to each other than female’s.ConclusionsThis study suggests that there are sexually different mechanisms to regulate the HPA and HPG axes during fetal development. Higher mRNA expression levels of endocrine axes components may be a mechanism to help females cope with prolonged androgen exposure over a long gestational period. Additionally, these findings suggest different coordination requirements of male and female endocrine axes during stages of fetal development.

Adaptive virtual team planning and coordination: a mathematical programming approach

Purpose The rise of remote work increasingly requires organizations to coordinate a single large, consolidated talent pool into ad-hoc, short-term project teams on demand. This problem involves many simultaneous considerations including project revenues and rejection costs, conflicting projects and roles, worker assignment costs, worker utilization preferences and limits, worker reassignment costs, and arbitrary role start and end times. Moreover, plans must be continuously updated in response to changing circumstances. This paper addresses the problem of dynamic virtual team planning and coordination. Design/methodology/approach We show this problem is NP-hard and provide a dynamic mixed integer linear programming (MILP) formulation for both optimal initial plan generation as well as continuous plan adjustment and re-optimization. We utilized a factorial experiment design to generate benchmark problems spanning a wide range of characteristics and conducted extensive computational experimentation using a common MILP solver. Findings Exactly optimal solutions to large, realistically sized problems were consistently obtained in short amounts of time. All observed solution times were sufficient to support the operational decision-making requirements of real-world virtual team coordination, demonstrating the viability of this approach. Practical implications The approach developed in this research can enable organizations to optimally coordinate virtual teams on a large scale and continually adjust plans in response to changing circumstances, all in an automated manner. Originality/value This paper addresses a new and complex problem of increasing importance to organizations due to the rise in remote work. We provide a problem formulation and exact approach for optimally solving both the planning and re-planning aspects of this problem.

Motor coordination induces social identity-A novel paradigm for the investigation of the group performance-identity link.

Joint action theorizing implies that any coordinated behaviour that induces co-representation with a partner should increase social identification, especially when the associated actions require a high degree of coordination and are experienced as being performed effectively. The current research provides a first test of this new theoretical prediction for complementary (rather than synchronous) joint actions. In each of two pre-registered experiments establishing a novel paradigm, participants performed a digital joystick task with a joint performance goal with three different partners. The task varied in coordination requirements across partners. In Experiment 1, results showed that when task segments were discrete between partners, they identified less as a group than when they had to coordinate their behaviour. Surprisingly, although constant coordination increased co-representation relative to intermittent coordination, it did not correspondingly increase social identification. However, performance correlated positively with identification; as performance was worse when participants had to coordinate, this may explain the results. Experiment 2 showed that performance is causally linked to identification when coordination is necessary. Taken together, our results suggest that experiencing effective coordination leads to greater social identification. In general, paradigms capable of examining the perceptual and motor aspects of collective behaviour may offer a new perspective on social identification in general and the performance-identification link in particular.

Mononuclear binding and catalytic activity of europium(III) and gadolinium(III) at the active site of the model metalloenzyme phosphotriesterase.

Lanthanide ions have ideal chemical properties for catalysis, such as hard Lewis acidity, fast ligand-exchange kinetics, high coordination-number preferences and low geometric requirements for coordination. As a result, many small-molecule lanthanide catalysts have been described in the literature. Yet, despite the ability of enzymes to catalyse highly stereoselective reactions under gentle conditions, very few lanthanoenzymes have been investigated. In this work, the mononuclear binding of europium(III) and gadolinium(III) to the active site of a mutant of the model enzyme phosphotriesterase are described using X-ray crystallography at 1.78 and 1.61 Å resolution, respectively. It is also shown that despite coordinating a single non-natural metal cation, the PTE-R18 mutant is still able to maintain esterase activity.

Dynamic co‐ordination networks in carboxylated nitrile rubber and development of self‐healing and recyclable rubber composites

AbstractMetal–ligand coordinated cross‐linked polymeric composites that can alter the network topology via a dynamic bond‐exchange mechanism have been recognized as very promising candidates to address the shortcomings of conventional cross‐linked composites, such as poor recyclability and self‐healing ability. This has led to much interest in the cross‐linking of elastomers via non‐covalent interactions with suitable metal ions. In this report, we present a simple but efficient approach to ferric ions (Fe3+) assisted crosslinking of carboxylated nitrile rubber (XNBR) in the presence of an aliphatic amine (Et3N). The dynamic coordination reaction via carboxylate functional group of nitrile rubber (XNBR) is employed to fulfill the coordination requirements of the central Fe3+ metal ion. This is confirmed by x‐ray photoelectron spectroscopy and Fourier‐transform infrared spectroscopy. The crucial role of Et3N in partially hindering and regulating the extent of crosslinking is investigated and mechanistically interpreted by swelling, differential scanning calorimetry, and rheological study. The tensile strength of ferric crosslinked XNBR could be enhanced up to four times than that of pure XNBR. Furthermore, the dynamic coordination‐driven network of XNBR offers excellent self‐healing (90% efficiency) and recyclability features (80% efficiency) for a composite of appropriate formulations.

Human–machine Teaming with Small Unmanned Aerial Systems in a MAPE-K Environment

The Human Machine Teaming (HMT) paradigm focuses on supporting partnerships between humans and autonomous machines. HMT describes requirements for transparency, augmented cognition, and coordination that enable far richer partnerships than those found in typical human-on-the-loop and human-in-the-loop systems. Autonomous, self-adaptive systems in domains such as autonomous driving, robotics, and Cyber-Physical Systems, are often implemented using the MAPE-K feedback loop as the primary reference model. However, while MAPE-K enables fully autonomous behavior, it does not explicitly address the interactions that occur between humans and autonomous machines as intended by HMT. In this article, we, therefore, present the MAPE-K HMT framework, which utilizes runtime models to augment the monitoring, analysis, planning, and execution phases of the MAPE-K loop to support HMT despite the different operational cadences of humans and machines. We draw on examples from our own emergency response system of interactive, autonomous, small unmanned aerial systems to illustrate the application of MAPE-K HMT in both a simulated and physical environment, and we discuss how the various HMT models are connected and can be integrated into a MAPE-K solution.

Modular Model and Simulation for Process Optimisation in Advanced Material Recovery Facilities (MRFs)

At a time when the supply of critical materials is threatened, waste recycling and reuse is an essential solution for human development. The role of Material Recovery Facilities (MRFs) to deliver efficiently high-purity material fractions as feedstock cannot be underestimated. However, MRF sorting processes need to remain adaptive with evolving smart technologies and systems that further enhance their effectiveness. For example, a re-designed MRF with AI-based robotics can improve the performance of waste recycling, leading to significant economic and environmental benefits. This study assesses the performance of potential optimisation methods for future proofing MRFs using modular simulation methods. The authors set out to review current robotics sorting technology and pointed out the challenge of efficiency analysis with multiple variables. The study develops a new conceptual model of efficiency analysis considering the identification and sorting limitations of robots, as well as the coordination requirements between robots and conveyor belts. A computational model is designed and developed by modularity program codes to help practitioners gain insight into the MRF performance by modifying the variables (composition of input waste, separation coefficients and configurations) and analysing the resulting assessment factors (purity and recovery). In the end, this study demonstrates the performance of the optimisation methods of MRF (two target materials for one robot and recirculation loops) through simulation.

Operating characteristics analysis and capacity configuration optimization of wind-solar-hydrogen hybrid multi-energy complementary system

Wind and solar energy are the important renewable energy sources, while their inherent natures of random and intermittent also exert negative effect on the electrical grid connection. As one of multiple energy complementary route by adopting the electrolysis technology, the wind-solar-hydrogen hybrid system contributes to improving green power utilization and reducing its fluctuation. Therefore, the moving average method and the hybrid energy storage module are proposed, which can smooth the wind-solar power generation and enhance the system energy management. Moreover, the optimization of system capacity configuration and the sensitive analysis are implemented by the MATLAB program platform. The results indicate that the 10-min grid-connected volatility is reduced by 38.7% based on the smoothing strategy, and the internal investment return rate can reach 13.67% when the electricity price is 0.04 $/kWh. In addition, the annual coordinated power and cycle proportion of the hybrid energy storage module are 80.5% and 90%, respectively. The developed hybrid energy storage module can well meet the annual coordination requirements, and has lower levelized cost of electricity. This method provides reasonable reference for designing and optimizing the wind-solar-hydrogen complementary system.

Semi-analytical dynamic modeling and fluid-structure interaction analysis of L-shaped pipeline

The traditional semi-analytic modeling is mainly aimed at the straight pipeline with simple boundary conditions. In contrast, the actual aero-engine pipeline needs to consider the effects of complex configuration, boundary and multiple clamps, so proposing an improved semi-analytic method to model an arbitrary fluid-conveying L-shaped pipeline is challenging. Based on the Hamiltonian principle, the differential equations of the L-shaped pipeline are derived. Then, the modal shape functions are determined under the conditions that the elastic support points and the joints of the straight pipeline and the curved pipeline meet the deformation coordination requirements. The proposed semi-analytical model is verified by comparing the natural frequencies and mode shapes obtained from the finite element method using ANSYS and experiment; the error of each order natural frequency is less than 5 %. In addition, the model is verified under various working conditions: different center angle and boundary conditions (clamp position and pipeline end constraints). The effects of the fluid velocity and pressure on the natural characteristics of the L-shaped pipeline are also analyzed. The results show that under the critical pressure of 60.51 MPa and the critical velocity of 247 m/s, the natural frequency decreases with the increase of fluid velocity and pressure. The proposed method can provide theoretical support for efficient and accurate modeling of complex spatial pipeline systems.

Integrating Function Allocation and Operational Event Sequence Diagrams to Support Human-Robot Coordination: Case Study of a Robotic Date Thinning System

State-of-the-art robots show promise in supporting but not completely replacing human work in most precision agriculture applications. For many potential agricultural robot applications, there are no comparable systems nor readily available information on the human operator activities to guide the systems engineering process. Such is the situation for Medjool date thinning, a tedious and hazardous manual operation for which technological assistance has yet to be developed. Here we describe using cognitive system engineering methods to develop operational concepts and human-robot coordination requirements for a pioneer system, a Robotic Medjool Date Thinning System (RDTS). We leveraged the abstraction hierarchy to characterize the RDTS’s envisioned goals and functionality. We developed alternative functional allocations to explore the design space based on the availability of different enabling technologies. After downselecting to the function allocation, including the technologies expected to be developed, we created operational event sequence diagrams to visualize the operation flow and to identify requirements related to the human operator and the joint human-robot system. Applying these methods in the early design stages helped to refine the human-robot coordination requirements and to identify gaps in the operational concept—they show great potential to support the introduction of agricultural robots and bring them to fruition.

Assisted teleoperation control of robotic endoscope with visual feedback for nasotracheal intubation

Endoscopic operation is one of the most difficult parts of nasotracheal intubation (NTI), a surgical procedure used to secure the airway of a patient. Due to the requirement of eye–hand coordination, manual operation of a flexible endoscope is challenging, even for an experienced surgeon. To enhance intubation efficiency, this paper developed a master–slave robotic nasotracheal intubation system (RNIS) for endoscopic operation. Movements in three degrees of freedom of the endoscope are controlled by the RNIS. An assisted teleoperation control strategy is designed to assist the operator in remotely controlling the pose, i.e., position and orientation, of the endoscope tip via a joystick. To ensure the efficiency of intubation, visual feedback assistance is hereby proposed, which fine-tunes the orientation of the endoscope tip as needed. The proposed system and methods are experimentally validated on a motion simulator and a phantom. The results demonstrated that the master–slave RNIS can successfully insert the flexible endoscope into the trachea of a phantom through the nasal cavity.

Chinese expert consensus on standardized inhaler device application in stable chronic airway diseases (2023)

Chinese expert consensus on standardized inhaler device application in stable chronic airway diseases (2023)

Statistical switching method to establish the minimal requirements of insulation coordination in double-circuit transmission lines

Statistical switching method to establish the minimal requirements of insulation coordination in double-circuit transmission lines

Development and image-guided control of a robotic endoscope system for nasotracheal intubation

Nasotracheal intubation (NTI) is an advanced airway management technique, in which a flexible endoscope is inserted into the patient’s trachea from the nasal cavity. Due to the hand-eye coordination requirement, the operation of the flexible endoscope in a narrow workspace is a challenge, even for experienced surgeons. In this study, a novel robotic nasotracheal intubation system (RNIS) is proposed to automatically steer the endoscope along the upper respiratory tract. The configuration of the RNIS meets the motion requirement of the flexible endoscope. A lumen center detection method with Kalman filter is designed to determine the position of the lumen center in endoscopic images. Then, a fuzzy logic-based control strategy is developed to enable the RNIS to achieve automatic endoscope steering. Control parameters are updated online using a fuzzy logic algorithm to handle uncertainty. Movements in three degrees of freedom of the endoscope are controlled by the RNIS using visual feedback. Finally, experiments based on a motion simulator and a training mannequin are conducted. Results demonstrate that the proposed RNIS can successfully steer the flexible endoscope along the upper respiratory tract. Automated robotic endoscopes outperform manual operations in terms of operational accuracy.

Heterogeneous Underwater Swarm of Robotic Fish

Underwater robotics is prevalent today in the field of undersea surveys. The current single-agent approach struggles to cover surveys of large areas, especially when visual analyses are required. Applications of underwater multi-robots fleets need to manage the coordination of the agents, which in turn stresses the already limited capabilities of underwater localization and communication. We propose a concept for a multilayered control architecture, which leverages visual recognition and swarm behavior to negotiate the coordination requirements of the single agent while retaining a significant level of control over the fleet of vehicles as a whole. This is obtained by including multiple control layers, paired with a heterogeneous composition of vehicles.

Detailing the idea of the design process of hydraulic automation objects

The work is touched to the design methods of the complex technical objects. The reason of the objects complication is the requirement of the dynamical processes coordination because the planed characteristics are needed. The main design stages idea – circuit diagram – simulation – structure are considered. The means of the design stages information representing of traditional approach are the relatively commonly and not consistent. It leads to design time increasing. In this work to structure the design information, coordinate the means of the different stage information representation with each others and detail design process are proposed. To do it the common information space of knowledge of the subject aria are separated on the streams. The streams represent information about the content, uniting, activities and requirements. The design process is represented as the transactions chain. Each transaction is based on the named streams and successively forms the state of the resulting functional stream. These states reflect the readiness levels of the designed object. Due to this way of means representation and detailing of information the coordination between different stages was provided. There are the possibilities to check the stage correctness executing also. As result the iteration reducing and time consumption of the design process are reached. The design process is illustrated by the example.

X-ray and molecular dynamics study of the temperature-dependent structure of FLiNaK

The atomic structure of FLiNaK and its evolution with temperature are examined with x-ray scattering and molecular dynamics (MD) simulations in the temperature range 460–636 °C. In accord with previous studies, it’s observed that the average nearest-neighbor (NN) cation-anion coordination number increases with increasing cation size, going from ∼4 for Li-F to ∼6.4 for K-F. In addition, we find that there is a coupled change in local coordination geometry – going from tetrahedral for Li-F to octahedral for Na to very disordered quasi-cuboidal for K. The varying geometry and coordination distances for the cation-anion pairs cause a relatively constant F-F next-nearest neighbor (NNN) distance of approximately 3.1 Å. This relatively fixed distance allows the F anions to assume an overall correlated structure very similar to that of a hard-sphere liquid with an extended radius which is beyond the normal F ion size but reflects the cation-anion coordination requirements. Careful consideration of the evolution of the experimental atomic distribution functions with increasing temperature shows that the changes in correlation at each distance can be understood within the context of broadening asymmetric neighbor distributions. Within the temperature range studied, the evolution of F-F correlations with increasing temperature is consistent with changes expected in a hard-sphere liquid simply due to decreasing density.