control designs
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Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 449
Author(s):  
Daniel Lang ◽  
Donald W. Radford

This study proposes a novel methodology to combine topology optimization and ply draping simulation to partition composite structures, improve structural performance, select materials, and enable more accurate representations of cost- and weight-efficient manufacturable designs. The proposed methodology is applied to a structure as a case study to verify that the methodology is effective. One design concept is created by subjecting the structure to a kinematic ply draping simulation to inform the partitioning of the structure, improve drapability and performance, and reduce structural defects. A second design concept is created that assumes that plies are draped over the entire structural geometry, forming an integral design. The two design concepts’ topologies are subsequently optimized to specify ideal material and ply geometries to minimize mass and reduce costs. The results indicate that the partitioned structure has a 19% lower mass and 15% lower material costs than the integral design. The two designs produced with the new methodology are also compared against two control designs created to emulate previously published methodologies that have not incorporated ply draping simulations. This demonstrates that neglecting the effects of ply draping produces topology optimization solutions that under-predict the mass of a structure by 26% and costs by 38%.


2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Bas B. L. Penning de Vries ◽  
Rolf H. H. Groenwold

Abstract Background Case-control designs are an important yet commonly misunderstood tool in the epidemiologist’s arsenal for causal inference. We reconsider classical concepts, assumptions and principles and explore when the results of case-control studies can be endowed a causal interpretation. Results We establish how, and under which conditions, various causal estimands relating to intention-to-treat or per-protocol effects can be identified based on the data that are collected under popular sampling schemes (case-base, survivor, and risk-set sampling, with or without matching). We present a concise summary of our identification results that link the estimands to the (distribution of the) available data and articulate under which conditions these links hold. Conclusion The modern epidemiologist’s arsenal for causal inference is well-suited to make transparent for case-control designs what assumptions are necessary or sufficient to endow the respective study results with a causal interpretation and, in turn, help resolve or prevent misunderstanding. Our approach may inform future research on different estimands, other variations of the case-control design or settings with additional complexities.


2021 ◽  
Author(s):  
Silvana Mareva ◽  
Danyal Akarca ◽  
Joni Holmes ◽  

Behavioural and language difficulties co-occur in multiple neurodevelopmental conditions. Our understanding of these problems has arguably been slowed by an overreliance on case-control designs, which limit the conclusions we can draw because they fail to capture the overlap across different neurodevelopmental disorders and the heterogeneity within them. In this study, we recruited a large transdiagnostic cohort of children with complex diagnosed and undiagnosed needs (N = 805) to identify distinct subgroups of children with common profiles of behavioural and language strengths and difficulties. We then investigated whether and how these data-driven groupings could be distinguished from a comparison sample (N = 158) on academic, socio-emotional, and neural white matter characteristics. We identified three distinct subgroups of children, each with different levels of difficulties in structural language, pragmatic communication, and hot and cool executive functions. All three subgroups struggled with academic and socio-emotional skills relative to the comparison sample, potentially representing three alternative but related developmental pathways to difficulties in these areas. The children with the weakest language skills had the most widespread difficulties with learning, whereas those with more pronounced difficulties with hot executive skills experienced the most severe difficulties within the socio-emotional domain. Each data-driven subgroup could be distinguished from the comparison sample based on both shared and subgroup-unique patterns of neural white matter organisation. These findings advance our understanding of commonly co-morbid behavioural and language problems and their relationship to behavioural outcomes and neurobiological substrates.


Machines ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 319
Author(s):  
Yi-Liang Yeh ◽  
Po-Kai Yang

This paper presents innovative reinforcement learning methods for automatically tuning the parameters of a proportional integral derivative controller. Conventionally, the high dimension of the Q-table is a primary drawback when implementing a reinforcement learning algorithm. To overcome the obstacle, the idea underlying the n-armed bandit problem is used in this paper. Moreover, gain-scheduled actions are presented to tune the algorithms to improve the overall system behavior; therefore, the proposed controllers fulfill the multiple performance requirements. An experiment was conducted for the piezo-actuated stage to illustrate the effectiveness of the proposed control designs relative to competing algorithms.


2021 ◽  
pp. 1-10
Author(s):  
Kenneth S. Kendler ◽  
Henrik Ohlsson ◽  
Jan Sundquist ◽  
Kristina Sundquist

Abstract Background – Comorbidity between psychiatric disorders is extensive but, from a genetic perspective, still poorly understood. Modern molecular genetic approaches to this problem are limited by a reliance on case–control designs. Methods – In 5 828 760 individuals born in Sweden from 1932–1995 with a mean (s.d.) age at follow-up of 54.4 (18.1), we examined family genetic risk score (FGRS) profiles including internalizing, psychotic, substance use and developmental disorders in 10 pairs of psychiatric and substance use disorders diagnosed from population registries. We examined these profiles in three groups of patients: disorder A only, disorder B only and comorbid cases with both disorders. Results – The most common pattern of findings, seen in five pairings, was simple and quantitative. Comorbid cases had higher FGRS than both non-comorbid cases for all (or nearly all) disorders. However, the pattern was more complex in the remaining five pairings and included qualitative changes where the comorbid cases showed no increases in FGRS for certain disorders and in a few cases significant decreases. Several comparisons showed an asymmetric pattern of findings with increases, in comorbidity compared to single disorder cases, of the FGRS for only one of the two disorders. Conclusions – The examination of FGRS profiles in general population samples where all disorders are assessed in all subjects provides a fruitful line of inquiry to understand the origins of psychiatric comorbidity. Further work will be needed, with an expansion of analytic approaches, to gain deeper insights into the complex mechanisms likely involved.


2021 ◽  
Author(s):  
Junyan Dong ◽  
Zhibo Tang ◽  
Hanbao Chen

This paper gives a general overview of relevant studies about oil spill emergency control designs, analyzes and discusses the structure, function and main contents of these designs. Besides, the paper proposes an integrated and practical design of emergency response steps, with related process. Taking the port area of Ma’ao as a case, this paper comprehensively studies the relationship between the time of rescue vessels arriving at the oil spill location and the range of the port that can be covered by these vessels as well as the protection facilities required for the relevant shoreline.


2021 ◽  
Vol 15 ◽  
pp. 211-222
Author(s):  
Navya Thirumaleshwar Hegde ◽  
Aldrin Claytus Vaz ◽  
C. G. Nayak

Unmanned Aerial Vehicles (UAVs) guidance, control and navigation have directed the attention of many researchers in both aerospace engineering as well as control theory. Due to the unique rotor structure of Tiltrotor hybrid UAVs, they exhibit special application value. Quad Tiltrotor UAVs set up a distinctive platform that satisfies the needs of the varying mission requirements by combining the conventional features of high-speed cruise capabilities of an aircraft and hovering capabilities of a helicopter and by tilting its four rotors. The aim of this research article is to control the attitude and altitude of the UAV in the presence of uncertainty using two different control techniques. This paper addresses the comparative analysis of the robust H-infinity controller with classical PID control designs for the transition manoeuvre of a hybrid UAV: the VTOL Tiltrotor UAV. The proposed controllers achieve hover to cruise mode transition and vice-versa. The main idea behind the design of controller is to model and analyze the UAV’s position and attitude dynamics. The desired flight trajectory and the transition manoeuvre is achieved by controlling the tilt angle in 15° intervals from 90° to 0° and vice-versa. Performance index subjected to IAE is estimated and compared for both the controllers in the presence of noise, disturbances and uncertainties. The results of simulation illustrate that the robust H-infinity controller achieves better transition, good adaptability, robust performance and robust stability for the whole flight envelope when compared with the PID controller.


2021 ◽  
pp. 83-99
Author(s):  
Renuka Loka ◽  
Alivelu M. Parimi ◽  
P. Shambhu Prasad

2021 ◽  
Vol 2 (2) ◽  
pp. 28-36
Author(s):  
Liqma amir, Herdy Juniawan, Tika Sari Dewy

Background : Communication is a general term that refers to a more specific term, A group of individuals to communicate various ideas and information. Flashcard media is a media card with picture that are useful for increasing vocabulary and learning words every day by using flashcard games. He flashcard have benefits for children, including learning as early as possible, developing memory, practicing concentration skill and improving vocabulary. Purpose : The aim of this study is to analyze the influence of flashcard media (picture cards) on the ability communication for autistic children. Method : The study method was pre-experimental with one group pretest and posttest without control designs. The number of samples in this study were 12 autistic children. Result : The results of the study by using the Paired T-Test, the average increase value obtained with a P-Value of 0.000 <0.05. Conclution: The conclusion of this study, that there was an influence of flashcard media (picture cards) on the communication skills of autistic children. It was recommended for further researchers that this flashcard media (picture card) can be used as an alternative for health promotion media for children with special needs autism.


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