Balancing a U-Shaped Assembly Line with a Heuristic Algorithm Based on a Comprehensive Rank Value

An aim of sustainable development of the manufacturing industry is to reduce the idle time in the product-assembly process and improve the balance efficiency of the assembly line. A priority relationship diagram is obtained on an existing assembly line in the laboratory by measuring the task time of the chassis model, analyzing the product structure, and designing the assembly process. The type-E balance model of the U-shaped assembly line is established and solved by a heuristic algorithm based on the comprehensive rank value. The type-E balance problem of the U-shaped assembly-line plan of the chassis model is obtained, and the production line layout is planned. Combining instances to compare the results of the heuristic algorithm, genetic algorithm, and simulated annealing, comparison of the results shows that the degree of load balancing is slightly higher than genetic algorithm and simulated annealing. The balance efficiencies obtained by the heuristic algorithm are smaller than the genetic algorithm and simulated annealing. The calculation time is significantly less than the genetic algorithm and simulated annealing, and the scale of instances has little effect on the calculation time. The results verify that the model and the algorithm are effective. This study provides a reference for the entire process of the U-shaped assembly-line, type-E balance and the assembly products in laboratories.

Rapid Dual-Task Decrements After a Brief Period of Manual Tracking in Simulated Weightlessness by Water Submersion

Objective Investigating dual-task (DT) performance during simulated weightlessness by water submersion, using a manual tracking and a choice reaction task. In contrast to previous work, we focus on performance changes over time. Background Previous research showed motor tracking and choice reaction impairments under DT and single-task (ST) conditions in shallow water submersion. Recent research analyzed performance as average across task time, neglecting potential time-related changes or fluctuations of task-performance. Method An unstable tracking and a choice reaction task was performed for one minute under ST and DT conditions in 5 m water submersion and on dry land in 43 participants. Tracking and choice reaction time performance for both tasks were analyzed in blocks of 10 seconds. Results Tracking performance deteriorated underwater compared to dry land conditions during the second half while performing one minute in DT conditions. Choice reaction time increased underwater as well, but independent of task time and type. Conclusion Tracking error increased over time when performing unstable tracking and choice reaction together. Potentially, physiological and psychological alterations under shallow submersion further strain the human system during DT operations, exceeding available recourse capacities such that DT performance deteriorated over time. Application Humans operating in simulated weightlessness underwater should be aware of substantial performance declines that can occur within a short amount of time during DT situations that include continuous tracking.

Motor Skill Training Effect on Real-Time Prefrontal Cortex Activation During Walking

We aimed to test the effects of motor skill training (MST) on gait automaticity measured by changes in prefrontal cortex (PFC) activation during actual walking. We used data from a 12-week trial of older adults (mean age=75.5, 60.5% women) randomized to standard physical therapy and standard+MST in a 1:1 ratio. Functional near infrared spectroscopy (fNIRS) measured PFC activation during simple and dual task walking. We will apply linear mixed models to assess effects of task, time, and MST on PFC activation. We will compare the PFC activation 1) during dual task walking compared to simple walking; 2) across visits after intervention; and 3) between participants receiving MST compared to standard physical therapy. These results will demonstrate whether gait automaticity, as evidenced by PFC activation during walking, is affected by MST.

Assessing usability of QIAreach QuantiFERON® platform in a high Tuberculosis prevalence low-resource setting

BackgroundWe aimed to assess the usability of QIAreach QuantiFERON® platform in a high Tuberculosis prevalence low-resource setting. Assay usability was assessed across 6 laboratories in Zambia.MethodsUsability of QIAreach QuantiFERON and training needs for assay implementation were assessed across three domains: effectiveness, efficiency, and user satisfaction. Nine laboratory workers participated in the study. For each task, metrics on success (pass, fail, pass with hints), total task time, and ease of use rating (five-point Likert scale) were collected.ResultsOverall tasks completion rate was from 89–100%. 1/9 participants, could not understand software instructions. Average time from set up to results ranged from 22 to 40 min. Users with experience performing the QFT-plus assay completed the test faster than users without experience, 26 min versus 35 min. Two participants had difficulty loading the sample on QIAreach eStick. Two participants could not adjust the pipette to the required volume of 150 µL. Two participants did not mix the test sample properly. One participant transferred the sample buffer twice and added insufficient plasma to the sample processing tube. Two participants added the test sample to eStick sample port many times. One participant added wrong information in the software. User satisfaction ranged from 2 to 5.ConclusionThe QIAreach QFT assay is suitable to be implemented in remote areas with limited infrastructure. Further studies are needed to establish assay's performances as well as the feasibility of introducing this new assay at larger scale to improve TB control in regions with limited infrastructure.

Organization of Students and Total Task Time: External and Internal Load Recorded during Motor Activity

The organization of the students and the time taken to execute the learning tasks determine the physical (external load) and physiological (internal load) demands the students support during physical education classes. The aim of this study was to determine which organizational and pedagogical elements used to design different learning tasks for soccer provoke greater external (Player Load (PL)) and internal (Heart Rate (HR)) load and thus help the students to fulfil the adequate physical activity recommendations (moderate to vigorous physical activity for ≥50% of class time). The organizational elements studied were (1) the participation type and (2) total task time, and the pedagogical element of (3) the game situation. A total of 40 students from the fifth year of primary education participated in the study distributed into two class groups. The basic analysis units were the data on physical activity recorded in each of the tasks carried out by the students during the practical sessions (1500 records), and they were recorded using WIMU ProTM inertial movement devices. A descriptive and inferential analysis was performed with the Mann–Whitney U and Kruskal–Wallis H statistical tests. The results recommend the following types of tasks with simultaneous participation: individual games, numerical inequality SSG, numerical equality SSG lasting less than 6 min, numerical equality SSG, and full games lasting between 6 and 10 min. This type of learning task makes the students move more (medium Player Load between 0.80 and 1.20) and at greater intensities (Heart Rate zone 4, between 161 and 181 bpm). Therefore, physical education teachers must take into account the pedagogical and organizational elements studied to make the sessions more intense and associated with health benefits.

Construct Validity of Simulation Model for Training the Ultrasound-Guided Nerve Block and Catheter Placement

Background: Continuous ultrasound-guided peripheral nerve block is a widely practiced technique that can be a challenge for young anesthesiologists. We developed a new simulation model for learning perineural catheter placement. This study aims to test the validity of the model and investigate the learning process of residents on this model. Methods: The simulation model was constructed with partial animal tissue and physical materials. Ultrasound-guided simulation of perineural catheter placement was then performed. Twenty-eight anesthesiologists representing novices, intermediates and experts were required to perform 30 trials within one single day. Practice trials were video-recorded to extract data of task time and performance errors. Construct validity were assessed. Results: Practicing on the simulation model, experts were able to achieve superior task performance, i.e., shorter task time (P < 0.001) and fewer performance errors (P < 0.001), than intermediates and novices. Learning curve recorded from young residents suggested that they were not able to reach the proficiency level as experts within one training day. Conclusions: This hybrid simulation model was capable of training the skills required for continuous ultrasound-guided peripheral nerve block. Future studies under this model need to concern extending the duration of the training phase for residents.

Assessment of Technical Means Quality Indicators for Smart Transport Systems

The purpose of this article is to show that it is necessary to assess the quality indicators for the technical means of smart transport systems. The quality of technical means, including smart transport systems, is associated with the selection of rational information processing technologies. Data in information systems is processed in different sections. The authors suggest an assessment technology for the operational quality of technical means of automated transport information systems. They identify the key quality indicators for the operation of technical means of information systems. The authors demonstrate that the operation of technical means can be characterized by the system task time, output data accuracy, and system implementability. They present the calculation of technical means quality indicators for smart transport systems

Multirobot Task Allocation in e-Commerce Robotic Mobile Fulfillment Systems

Robotic Mobile Fulfillment System (RMFS) is a new type of parts-to-picker order picking system and has become the development trend of e-commerce logistics distribution centers. There are usually a large number of tasks need to be allocated to many robots and the picking time for e-commerce orders is usually very tight, which puts forward higher requirements for the efficiency of multirobot task allocation (MRTA) in e-commerce RMFS. Current researches on MRTA in RMFS seldom consider task correlation and the balance among picking stations. In this paper, a task time cost model considering task correlation is built according to the characteristics of the picking process. Then, a multirobot task allocation model minimizing the overall picking time is established considering both the picking time balance of picking stations and the load balance of robots. Finally, a four-stage balanced heuristic auction algorithm is designed to solve the task allocation model and the tasks with execution sequence for each robot are obtained. By comparing with the traditional task time cost model and the algorithm without considering the balance among picking stations, it is found that the proposed model and algorithm can significantly shorten the overall picking time.

Levels of Agreement for the Direction of Inter-Limb Asymmetry during Four Simple Change-of-Direction Tests in Young Male Handball Players: A Pilot Study

The purpose of this pilot study was to investigate the effects of change-of-direction (CoD) angle (90° vs. 180°) and the inclusion of acceleration approach on total task time, CoD deficit, and agreement regarding inter-limb asymmetry direction across CoD tasks. The sample included 13 young male handball players (age: 22.4 ± 3.2 years). The CoD tasks were performed over a 10 m distance with 90° and 180° turns. Both CoD tasks were performed under two conditions: (1) from the standing start and, (2) with a 10 m prior acceleration approach. Linear sprint times over a 10 m distance were also recorded for the purpose of determining the CoD deficit. The differences between the outcomes of different test variants were assessed with pairwise t-tests and associated Cohen’s d effect size. The agreement in terms of inter-limb asymmetry direction was assessed descriptively, using percentage of agreement. Results showed that the inclusion of the 10 m approach reduced the total task time (mean differences ranging between 0.26 and 0.35 s; d = 2.27–4.02; p < 0.002). The differences between 90° and 180° turn times were statistically significant under both conditions: (a) without approach (0.44–0.48 s; d = 4.72–4.84; all p < 0.001), and (b) with approach (0.50–0.54 s; d = 4.41–5.03; p < 0.001). The agreement regarding inter-limb asymmetry direction among the tasks was 30.7–61.5%. The differences between the tasks could be explained by the angle–velocity trade-off. The results of this study imply that the CoD tasks should not be used interchangeably when assessing inter-limb asymmetries.

Time and space multi-manned assembly line balancing problem using genetic algorithm

Purpose: Time and Space assembly line balancing problem (TSALBP) is the problem of balancing the line taking the area required by the task and to store the tools into consideration. This area is important to be considered to minimize unplanned traveling distance by the workers and consequently unplanned time waste. Although TSALBP is a realistic problem that express the real-life situation, and it became more practical to consider multi-manned assembly line to get better space utilization, few literatures addressed the problem of time and space in simple assembly line and only one in multi-manned assembly line. In this paper the problem of balancing bi-objective time and space multi-manned assembly line is proposedDesign/methodology/approach: Hybrid genetic algorithm under time and space constraints besides assembly line conventional constraints is used to model this problem. The initial population is generated based on conventional assembly line heuristic added to random generations. The objective of this model is to minimize number of workers and number of stations.Findings: The results showed the effectiveness of the proposed model in solving multi-manned time and space assembly line problem. The proposed method gets better results in solving real-life Nissan problem compared to the literature. It is also found that there is a relationship between the variability of task time, maximum task time and cycle time on the solution of the problem. In some problem features it is more appropriate to solve the problem as simple assembly line than multi-manned assembly line.Originality/value: It is the first article to solve the problem of balancing multi-manned assembly line under time and area constraint using genetic algorithm. A relationship between the problem features and the solution is found according to it, the solution method (one sided or multi-manned) is defined.