Genetic Algorithm-Based Trajectory Optimization for Digital Twin Robots

Mobile robots have an important role in material handling in manufacturing and can be used for a variety of automated tasks. The accuracy of the robot’s moving trajectory has become a key issue affecting its work efficiency. This paper presents a method for optimizing the trajectory of the mobile robot based on the digital twin of the robot. The digital twin of the mobile robot is created by Unity, and the trajectory of the mobile robot is trained in the virtual environment and applied to the physical space. The simulation training in the virtual environment provides schemes for the actual movement of the robot. Based on the actual movement data returned by the physical robot, the preset trajectory of the virtual robot is dynamically adjusted, which in turn enables the correction of the movement trajectory of the physical robot. The contribution of this work is the use of genetic algorithms for path planning of robots, which enables trajectory optimization of mobile robots by reducing the error in the movement trajectory of physical robots through the interaction of virtual and real data. It provides a method to map learning in the virtual domain to the physical robot.

Motor Imagination of Lower Limb Movements at Different Frequencies

Motor imagination (MI) is the mental process of only imagining an action without an actual movement. Research on MI has made significant progress in feature information detection and machine learning decoding algorithms, but there are still problems, such as a low overall recognition rate and large differences in individual execution effects, which make the development of MI run into a bottleneck. Aiming at solving this bottleneck problem, the current study optimized the quality of the MI original signal by “enhancing the difficulty of imagination tasks,” conducted the qualitative and quantitative analyses of EEG rhythm characteristics, and used quantitative indicators, such as ERD mean value and recognition rate. Research on the comparative analysis of the lower limb MI of different tasks, namely, high-frequency motor imagination (HFMI) and low-frequency motor imagination (LFMI), was conducted. The results validate the following: the average ERD of HFMI (−1.827) is less than that of LFMI (−1.3487) in the alpha band, so did (−3.4756 < −2.2891) in the beta band. In the alpha and beta characteristic frequency bands, the average ERD of HFMI is smaller than that of LFMI, and the ERD values of the two are significantly different ( p = 0.0074 < 0.01 ; r = 0.945). The ERD intensity STD values of HFMI are less than those of LFMI. which suggests that the ERD intensity individual difference among the subjects is smaller in the HFMI mode than in the LFMI mode. The average recognition rate of HFMI is higher than that of LFMI (87.84% > 76.46%), and the recognition rate of the two modes is significantly different ( p = 0.0034 < 0.01 ; r = 0.429). In summary, this research optimizes the quality of MI brain signal sources by enhancing the difficulty of imagination tasks, achieving the purpose of improving the overall recognition rate of the lower limb MI of the participants and reducing the differences of individual execution effects and signal quality among the subjects.

Neutralization of Transport Documents in Road Transport

In 1956 there was a significant step in international road freight transport – conclusion of Convention on the contract of carriage in international road freight transport (CMR Convention), the basic purpose of which was to unify the rules in the international transport of goods and thus promote the development of international trade. From a practical point of view, this was very important for both carriers and transporters. The Convention describes the most important document in the carriage of goods – the CMR consignment note.Recently, the term «neutralization» has been used in connection with the CMR consignment note, which is considered as an interference with the system of functioning of transport documents, which aims to obscure the actual movement of the consignment during transport. At the same time, neutralization of the consignment note is not so much contrary to legal norms as it can lead to undesirable consequences for carriers. For this reason, the question of whether it is possible to neutralize the CMR consignment note in accordance with the current rules and whether the neutralization of the CMR consignment note does not violate the functionality of the existing system is relevant. Therefore, the objective of this work is to study the reasons and methods for neutralizing CMR consignment notes, as well as options for handling neutralized consignment notes.Considering that neutralization of the consignment note has become a relatively common practice and means the exchange of original consignment notes or transport documents with other consignment notes or transport documents, canceling the actions of the first consignment note, in the article the authors, based on their own research, identified the possibilities of using the neutralization of the CMR consignment note in practice for certain types of goods, routes of the most frequent use, as well as the risks of these procedures in road transport.

Reliability of start and stop control of hydraulic actuation for the insertion of electrode arrays

Atraumatic insertions of electrode arrays (EA) into the cochlea aim to preserve natural structures and residual hearing. However, there is a limit as to how smooth and slow a surgeon can insert an EA. As a potential solution, we recently presented a tool (cochlea hydro drive, CHD) that makes use of an infusion pump to prompt and control the desired, continuous and very slow (< 1 mm/s) forward movement for such insertions. The present work further describes the onset, delay and cessation of the hydraulic actuation in response to different start and stop mechanisms, to better understand the safety of its application for cochlear implant surgery. Methods: Our previously designed tool was used to perform insertions of an EA into an artificial scala tympani model. The prototype is designed to hold an EA, which is then actuated by a standard infusion pump programmed to operate at 0.4 mm/ and 0.1 mm/s. A tubing system between the CHD and the pump includes a three-way valve. Ten insertions were operated using the functions of the pump and ten using the valve. Results: From the programmed start to the actual movement, we observed a larger average delay using the pump’s start function (5 s at 0.4 mm/s; 17 s at 0.1 mm/s) vs. opening the valve (< 0.7 s for both velocities). Moreover, the average cessation of movement with the valve closure was almost immediate (0.7 s for both velocities; this corresponds to < 0.1 mm with the slower tested velocity), as opposed to 60- 80 s delay when using the pump’s stop function. Conclusion: The use of a 3-way valve facilitates motion cessation to the high accuracy level required for cochlear implant surgery. These promising findings support future clinical translation of our tool.

The Dynamic Boundaries of The Self: Serial Dependence In Embodied Sense of Agency

The feeling of control over one’s actions, termed the Sense of Agency (SoA), delineates one’s experience as an embodied self. Although, this embodied experience is typically perceived as stable over time, recent theoretical accounts highlight the experience-dependent and dynamic nature of the embodied self. In this study we examined how recent experiences modulate SoA (i.e., serial dependence), and disambiguated the unique contributions of previous stimuli and choices on subsequent SoA judgments. In addition, we examined whether these effects persist across different domains of perceptual alteration. We analyzed two independent datasets of the Virtual Hand (VH) task (N = 100 participants) in which a sensorimotor conflict is introduced between the presented visual feedback and the actual movement performed. In Dataset 1, which included only temporal alterations, we found that previous stimuli recalibrate current perception, increasing the likelihood of the current choice to be different than the previous choice. Whereas previous choices induce a repetition bias increasing the likelihood to repeat choices across trials. Thus, previous external stimuli and self-generated choices exert opposing influences on SoA. We replicated these findings in Dataset 2, in which the VH task was tested with alterations in both temporal and spatial domains. In addition, we discovered that previous stimuli from a different perceptual domain exert a recalibration effect similar to stimuli from the same domain. Thus, SoA is constantly shaped by our previous subjective choices and objective stimuli experienced even across different perceptual domains. This highlights how SoA may act as unifying construct organizing our experience of the self over time and across perceptual experiences.

Tracking Response Dynamics of Sequential Working Memory in Patients With Mild Parkinson’s Disease

The ability to sequence thoughts and actions is impaired in Parkinson’s disease (PD). In PD, a distinct error pattern has been found in the offline performance of sequential working memory. This study examined how PD’s performance of sequential working memory unfolds over time using mouse tracking techniques. Non-demented patients with mild PD (N = 40) and healthy controls (N = 40) completed a computerized digit ordering task with a computer mouse. We measured response dynamics in terms of the initiation time, ordering time, movement time, and area under the movement trajectory curve. This approach allowed us to distinguish between the cognitive processes related to sequence processing before the actual movement (initiation time and ordering time) and the execution processes of the actual movement (movement time and area under the curve). PD patients showed longer initiation times, longer movement times, and more constrained movement trajectories than healthy controls. The initiation time and ordering time negatively correlated with the daily exposure to levodopa and D2/3 receptor agonists, respectively. The movement time positively correlated with the severity of motor symptoms. We demonstrated an altered temporal profile of sequential working memory in PD. Stimulating D1 and D2/3 receptors might speed up the maintenance and manipulation of sequences, respectively.

Nodule Deformation of PVA Roller Brushes on a Rotating Plate: Optimum Cleaning for Nanosized Particles due to Liquid Absorption and Desorption of Sponge Deformation

It is very difficult to remove extremely small particles from the surface of the wafer. Here, we proposed a new cleaning strategy using brush scrubbing, namely, nodule deformation induced fluid flow. Liquid absorption and desorption due to brush deformation enhance the mixing of liquids containing small particles. In this study, we developed a setup that reproduced the actual movement of PVA roller brushes on a rotating wafer and observed the contact surface of the brush nodule. We modeled the brush nodule deformation for each rotating condition. As a result, three types of nodule deformation were observed. In most cases, the nodule side face, rather than the bottom face was mainly in contact with the wafer surface. Moreover, we compared two types of roller brushes, normal cylindrical nodules, and edge treated nodules and found that the deformation can be significantly changed by chamfering nodule edge.

Spatial constraints and cognitive fatigue affect motor imagery of walking in people with multiple sclerosis

Motor imagery (MI) is the mental simulation of an action without any overt motor execution. Interestingly, a temporal coupling between durations of real and imagined movements, i.e., the so-called isochrony principle, has been demonstrated in healthy adults. On the contrary, anisochrony has frequently been reported in elderly subjects or those with neurological disease such as Parkinson disease or multiple sclerosis (MS). Here, we tested whether people with MS (PwMS) may have impaired MI when they imagined themselves walking on paths with different widths. When required to mentally simulate a walking movement along a constrained pathway, PwMS tended to overestimate mental movement duration with respect to actual movement duration. Interestingly, in line with previous evidence, cognitive fatigue was found to play a role in the MI of PwMS. These results suggest that investigating the relationship between cognitive fatigue and MI performances could be key to shedding new light on the motor representation of PwMS and providing critical insights into effective and tailored rehabilitative treatments.

Analysis of Cargo Release Services with Process Mining

Process Mining (PM) uses event logs extracted from process-oriented IS in order to uncover, analyse, diagnose and improve processes. However, the number of studies demonstrating PM applicability is limited, particularly in the field of logistics. This paper presents a methodological framework for a multi-faceted analysis of real-life event logs based on PM and the usefulness of its techniques, combined with traditional IE&M methods, thus offering an innovative approach on multiple levels by combining the use of PM and more traditional methods; using PM to demonstrate the actual movement of goods and generate a physical map of movements inside the warehouse; and enabling continuous tracking. A case-study, implemented on the cargo release process of a large Israeli logistics company, demonstrates this approach. Results reflect a major gap between the actual and the described processes, as an automatic creation of the process from logs shows that 64% of the customers received their goods after 4.5 hours (instead of 90 minutes, as service standard requires). Practical implications include detailed steps and a recommendation for additional analyses. Research value analysis shows that PM techniques constitute an ideal means to tackle organizational challenges by reflecting real-time situations, suggesting process improvements and creating companywide process awareness.

Food sovereignty, Diné ontologies: spiritual and political ecology as tools for self-determination

This article focuses on the different actors involved in the food sovereignty movement in the Navajo Nation. By first looking at the historical roots of colonization and western dominance over Indigenous lands and their food systems, I try to give some perspective on the actual movement to end colonization and capitalism. Both are seen as linked and are considered obstacles for the self-determination of the Navajos and Indigenous Peoples in general. The different actors involved (farmers, grassroots activists, intellectuals and academics) put forth food sovereignty as a key tool for decolonization. This might include a structural change in their political and economical lives, with interpersonal conflicts and frictions with the tribal government and the federal one. The tensions between the extractive economy, environmentalists and food sovereignty are present in the Navajo nation and impact their communities and the quality of their lives.