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"Design criteria"
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Automatic Design of Robot Swarms under Concurrent Design Criteria: A Study Based on Iterated F‐Race
Automatic design is an appealing approach to realizing robot swarms. In this approach, a designer specifies a mission that the swarm must perform, and an optimization algorithm searches for the control software that enables the robots to perform the given mission. Traditionally, research in automatic design has focused on missions specified by a single design criterion, adopting methods based on single‐objective optimization algorithms. In this study, we investigate whether existing methods can be adapted to address missions specified by concurrent design criteria. We focus on the bi‐criteria case. We conduct experiments with a swarm of e‐puck robots that must perform sequences of two missions: each mission in the sequence is an independent design criterion that the automatic method must handle during the optimization process. We consider modular and neuroevolutionary methods that aggregate concurrent criteria via the weighted sum, hypervolume, or l2 $l^{2} $ ‐norm. We compare their performance with that of Mandarina, an original automatic modular design method. Mandarina integrates Iterated F‐race as an optimization algorithm to conduct the design process without aggregating the design criteria. Results from realistic simulations and demonstrations with physical robots show that the best results are obtained with modular methods and when the design criteria are not aggregated. The study explores a novel approach to the automatic design of robot swarms using a bi‐criteria optimization method called Mandarina. It compares Mandarina with other methods, focusing on performance across sequential tasks. The results highlight Mandarina's effectiveness in generating robot behavior that balances multiple design criteria without needing human intervention, showcasing its potential for complex missions.
Journal Article
Biochar imparted constructed wetlands (CWs) for enhanced biodegradation of organic and inorganic pollutants along with its limitation
The remediation of polluted soil and water stands as a paramount task in safeguarding environmental sustainability and ensuring a dependable water source. Biochar, celebrated for its capacity to enhance soil quality, stimulate plant growth, and adsorb a wide spectrum of contaminants, including organic and inorganic pollutants, within constructed wetlands, emerges as a promising solution. This review article is dedicated to examining the effects of biochar amendments on the efficiency of wastewater purification within constructed wetlands. This comprehensive review entails an extensive investigation of biochar’s feedstock selection, production processes, characterization methods, and its application within constructed wetlands. It also encompasses an exploration of the design criteria necessary for the integration of biochar into constructed wetland systems. Moreover, a comprehensive analysis of recent research findings pertains to the role of biochar-based wetlands in the removal of both organic and inorganic pollutants. The principal objectives of this review are to provide novel and thorough perspectives on the conceptualization and implementation of biochar-based constructed wetlands for the treatment of organic and inorganic pollutants. Additionally, it seeks to identify potential directions for future research and application while addressing prevailing gaps in knowledge and limitations. Furthermore, the study delves into the potential limitations and risks associated with employing biochar in environmental remediation. Nevertheless, it is crucial to highlight that there is a significant paucity of data regarding the influence of biochar on the efficiency of wastewater treatment in constructed wetlands, with particular regard to its impact on the removal of both organic and inorganic pollutants.
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Journal Article
Multi-Objective Optimal Design of Detention Tanks in the Urban Stormwater Drainage System: Framework Development and Case Study
Detention tank plays an important role in the flooding control in the downstream areas of the urban stormwater drainage system (USDS) during the wet weather seasons. For complex watersheds with specific local flooding control policies, the conventional optimization and design methods are found to be not sufficient for effectively and optimally locating and sizing appropriate detention tanks any more. This paper investigates the optimal design of detention tanks under the constraints of local flooding control criteria, with the aim to develop an efficient and robust method and framework for the design of detention tank network. Coupled with the SWMM-based hydraulic simulation, a modified particle swarm optimizer is adopted to find out non-dominated solutions to minimize both the engineering cost and flooding risks by taking the local design criteria into consideration for the more realistic local engineering application. To validate the proposed method, a real-life case in SA city in China is taken for example to obtain optimal layout and sizes of the detention tank network under different construction factors and design conditions. Different rainfall return periods are also tested to guarantee the robustness of the optimal solutions. The results of this study confirm the feasibility and validity of the proposed methodological framework for multi-objective optimal design of detention tanks in the USDS.
Journal Article
Smoke Control Strategy and Design Criterion in Tunnel Fire Hazards Using Point Extraction Ventilation: Experimental Analysis and Theoretical Modeling
The hot and toxic smoke is a major reason for deaths and injuries in tunnel fire hazards, therefore, it is of vital importance for safe evacuation to effectively control the smoke. This paper proposed a smoke control strategy, i.e., completing smoke extraction, and developed the design criterion of exhaust rate based on small-scale experiments and theoretical analysis. The heat release rate (HRR), damper length, and interval were considered. Experimental results showed the critical exhaust rate for completing smoke extraction rose with the increase in HRR and declined with a growing damper interval. Besides, it first rapidly decreased and then turned to be smooth with rising damper length. Subsequently, the ratio of the suction force, Fd to the force, Fs was adopted to determine the completing smoke extraction using force analysis. The results illustrated that the HRR and damper interval barely affect the relative magnitude between the suction force, Fd, and the force, Fs. It was linearly dependent on the dimensionless damper length and then exponentially grew. The critical length of the damper was 0.1 m. Finally, a prediction model was established, and the evaluated results deviated from the experimental data within 15%.
Journal Article
A Systematic Approach towards the Integration of Initial Airworthiness Regulatory Requirements in Remotely Piloted Aircraft System Conceptual Design Methodologies
The regulatory framework of Remotely Piloted Aircraft Systems (RPASs) has recently experienced an extraordinary evolution. This article seeks to improve the integration of certification considerations in RPAS conceptual design approaches so as to enhance the safety, certifiability and competitiveness of their resulting designs. The first part of the research conducts a two-stage analysis of contemporary regulations related to an RPAS’s initial airworthiness. In the first stage, the broad international regulation paradigm is evaluated attending to a set of criteria that are tightly related to both airworthiness and design considerations. The second stage keeps the most promising documents from a design–integration standpoint, which are assessed according to their applicability considering both design and operational aspects. The results of this analysis provide insights regarding the main issues in airworthiness design criteria extraction and integration in design methodologies. To aid the designer in surmounting these challenges, a flexible procedure named DECEX is developed. Considering the documents and findings from the survey, and attending to the scope of the design methodology being developed, it aids in establishing a complete regulatory document corpus and in comparing and extracting the applicable airworthiness design criteria. Two case studies for different RPAS types are conducted to demonstrate its application.
Journal Article
Fault estimation for nonlinear systems: an observer structure design criterion technique
This paper mainly focuses on the observers design and fault estimation for nonlinear systems with faults. The considered nonlinear system is assumed to be represented by T-S fuzzy models or from a LPV system, where the coefficient matrix of measured output is time-varying. A lower triangle matrix (LTM)-based observer structure design criterion (OSDC) for the given nonlinear system is proposed. Under the proposed LTM-based OSDC, an estimation observer with generality and relaxed constraints is designed, by which the fault occurring in the system can be well estimated online. Linear matrix inequality (LMI)-based stability conditions for the estimation error dynamics are given. Simulation examples test the proposed OSDC technique.
Journal Article
Nonspherical photonic scatterers and design criterion for efficient passive daytime radiative cooling
Passive daytime radiative cooling (PDRC) exhibits efficient cooling performance to reduce global fossil energy consumption and has attracted enormous interest. An efficient PDRC technology for achieving daytime subambient cooling is supposed to exhibit ultra-high solar reflectivity and infrared emissivity within atmospheric windows, among which ultra-high solar reflectivity is the principal property. In most PDRC technologies, spherical particles are selected as scatterers to achieve high solar reflectivity because the Mie scattering effect of spherical scatterers can provide a high scattering efficiency. However, the weak backward scattering of spherical scatterers remains a drawback. In this study, several nonspherical scatterers with strong backward scattering are introduced and researched systematically. The numerical analysis results indicate that pyramidal scatterers provide the strongest backward scattering and square/circular scatterers exhibit the highest scattering efficiency. Besides, by considering scattering efficiency and asymmetry factor comprehensively, a dimensionless evaluation parameter is proposed, which can be employed as a quantitative design criterion to achieve the optimal-object-oriented designing of superior scatterers. This work can provide an innovative strategy for designing efficient passive daytime radiative cooling materials.
Journal Article
Optimal Design Criteria of Tandem Configuration for High-Load Compressor Cascades
Axial overlap (AO) and percent pitch (PP) are considered as key position configuration parameters that affect the tandem cascade performance. The objective of the current study is to investigate the optimal design criteria for these two parameters in tandem cascades of subsonic highly-loaded two-dimensional compressors. Before that, the influence mechanisms of AO and PP are explored separately. Research results show that higher PP is beneficial for decreasing rear blade (RB) load, but an invalidity of gap flow occurs when it approaches 1. The change in AO has an influence on the adverse pressure gradient of the front blade (FB), and it also affects the gap flow strength and FB wake development. Then, the optimal design criteria for AO and PP are obtained in a large design space, which clarifies the matching relationship of the two parameters at different operating conditions. The best global range of AO is about −0.05 to 0.05 while PP is between 0.85 to 0.92, and PP should be smaller to avoid performance degradation as AO increases. According to the fault tolerance in practical applications, PP should be closer to the lower bound to ensure that the deterioration boundary is wide enough.
Journal Article
Energy efficiency characteristic analysis of tri-coil PT symmetric MC-WPT systems
The parity-time (PT) symmetric magnetic coupling wireless power transfer (MC-WPT) system has received a great deal of attention since it was proposed. Its transmission efficiency has been greatly improved when compared with previous research. The operational amplifier (OA) is a typical construction method for PT symmetric MC-WPT systems. On this basis, to achieve a higher transmission efficiency and a longer effective power transmission distance at the same time, this paper constructs an OA-based tri-coil PT symmetric MC-WPT system. The analytical expressions of its singularity, PT symmetric state, and PT symmetric broken state are obtained. Then a complete set of parameter design criteria for the tri-coil PT symmetric system is derived. The transmission efficiency and resonant frequency of two-coil and tri-coil system are simulated on MATLAB software, and the simulation results are consistent with the theoretical analysis results. Finally, an experimental device is constructed to further verify the correctness of the theory. This paper demonstrates that the effective power transmission distance of the tri-coil PT symmetric MC-WPT system is more than twice that of the two-coil PT symmetric MC-WPT system, which can achieve a good balance between transmission efficiency and transmission distance.
Journal Article