Greedy Heuristics for Distributed Job Shop Problems

AbstractThis paper studies the problem of scheduling distributed job shops where the classical single-facility job shop is extended to the multi-facility one. The problem is mathematically formulated by a mixed integer linear programming model. The small sized problems are optimally solved using commercial software of CPLEX. Three greedy heuristics, as well as adapting three well-known heuristics, are developed to solve large sized problems. The idea of the proposed heuristics is to iteratively insert operations (one at each iteration) into a sequence to build up a complete permutation of operations. The performance of the model and the six heuristics are comprehensive evaluated by numerical experiments. The results show the model and greedy heuristics are effective for the problem

Extreme bendability of DNA double helix due to bending asymmetry

Experimental data of the DNA cyclization (J-factor) at short length scales, as a way to study the elastic behavior of tightly bent DNA, exceed the theoretical expectation based on the wormlike chain (WLC) model by several orders of magnitude. Here, we propose that asymmetric bending rigidity of the double helix in the groove direction can be responsible for extreme bendability of DNA at short length scales and it also facilitates DNA loop formation at these lengths. To account for the bending asymmetry, we consider the asymmetric elastic rod (AER) model which has been introduced and parametrized in an earlier study (B. Eslami-Mossallam and M. Ejtehadi, Phys. Rev. E 80, 011919 (2009)). Exploiting a coarse grained representation of DNA molecule at base pair (bp) level, and using the Monte Carlo simulation method in combination with the umbrella sampling technique, we calculate the loop formation probability of DNA in the AER model. We show that, for DNA molecule has a larger J-factor compared to the WLC model which is in excellent agreement with recent experimental data.Comment: 8 pages, 9 figure

Effects of a 12-Week Global Corrective Exercise Intervention on Sway Back Posture in Young Adults: A Randomized Controlled Trial

Background: Sway back posture (SBP) is a common postural deviation of sagittal alignment and is the most common postural deviation in 18 to 28-year-old individuals, but there is no standard exercise protocol for treating SBP. Our objective was to assess the effectiveness of the global corrective exercise intervention (GCEI) on spinal posture of healthy individuals 18-25 years of age with SBP. Methods: This study was a randomized controlled design with a parallel group, two-arm trial with 1:1 allocation ratio. Seventy participants (mean age 20.9±2.1 years) with SBP (⩾ 10°) were enrolled in the study for 12 weeks. The participants were randomly assigned to an exercise (n=35) or control group (n=35). The targeted global spine strengthening and stretching exercise intervention included core and postural training, delivered by a corrective exercise specialist in 2 groups of 20 and 15 participants 3 times a week for 12 weeks. Forward head angle and sway angle were measured using a digitized side-view photograph. Kyphosis index and llordosis index were measured using a flex curve ruler. Results: The 12-week intervention program resulted in significant within group differences in forward head, kyphosis, lordosis and postural sway angle (p<0.001). There was also a significant between group difference in the changes of all postural variables (p<0.001). Conclusions: The GCEI resulted in improved sway back posture in our sample of 18-25-year-old participants. This study supports the theoretical basis for clinical rehabilitation of postural deviations. Further studies are required to generalize these findings to other age and population groups. Key words: posture, sway back, corrective exercise, spinal alignmen

Effects of a 12-Week Global Corrective Exercise Intervention on Sway Back Posture in Young Adults: A Randomized Controlled Trial

Background: Sway back posture (SBP) is a common postural deviation of sagittal alignment and is the most common postural deviation in 18 to 28-year-old individuals, but there is no standard exercise protocol for treating SBP. Our objective was to assess the effectiveness of the global corrective exercise intervention (GCEI) on spinal posture of healthy individuals 18-25 years of age with SBP. Methods: This study was a randomized controlled design with a parallel group, two-arm trial with 1:1 allocation ratio. Seventy participants (mean age 20.9±2.1 years) with SBP (⩾ 10°) were enrolled in the study for 12 weeks. The participants were randomly assigned to an exercise (n=35) or control group (n=35). The targeted global spine strengthening and stretching exercise intervention included core and postural training, delivered by a corrective exercise specialist in 2 groups of 20 and 15 participants 3 times a week for 12 weeks. Forward head angle and sway angle were measured using a digitized side-view photograph. Kyphosis index and llordosis index were measured using a flex curve ruler. Results: The 12-week intervention program resulted in significant within group differences in forward head, kyphosis, lordosis and postural sway angle (p<0.001). There was also a significant between group difference in the changes of all postural variables (p<0.001). Conclusions: The GCEI resulted in improved sway back posture in our sample of 18-25-year-old participants. This study supports the theoretical basis for clinical rehabilitation of postural deviations. Further studies are required to generalize these findings to other age and population groups. Key words: posture, sway back, corrective exercise, spinal alignmen

Impulse voltage distribution and frequency response of intershield windings

Impulse voltage distributions in continuous disk windings are nonlinear, due to the small series capacitance of the winding. Consequently, transformer manufacturers often design large power transformers with interleaved windings to increase series capacitance, but in doing so reduce the value of the initial impulse voltage distribution coefficient α given by α = √(Cg/Cs), (1) where Cg is the shunt capacitance and Cs is the series capacitance of the winding. Sometimes fully interleaved windings are employed because they are more reliable, ensuring that the transformer will operate properly under lightning strike

Operating Room Scheduling Optimization Based on a Fuzzy Uncertainty Approach and Metaheuristic Algorithms

Today, planning and scheduling problems are the most significant issues in the world and make a great impact on improving organizational productivity and serving systems such as medical and healthcare providers. Since operating room planning is a major problem in healthcare organizations, the optimization of medical staff and equipment plays an essential role. Thus, this study presents a multi-objective mathematical model with a new categorization (preoperative, intraoperative, and postoperative) to minimize operating room scheduling and the risk of using equipment. Time constraints in healthcare systems and medical equipment limited capacity are the most significant considered limitation in the present study. In this regard, since the duration of patient preparation and implementation of treatment processes occur in three states of optimistic, pessimistic, and normal, the introduced parameters are examined relying on a fuzzy uncertainty analysis of the problem. Hence, the model is measured in a real numerical solution sample in a medical center to evaluate and confirm the proposed mathematical model. Then, two meta-heuristic algorithms (NRGA and NSGAII) are implemented on the mathematical model to analyze the proposed model. Finally, the research results indicate that the NSGA-II is more efficient in the operating room scheduling problem

Influence of gravitational field on quantum-nondemolition measurement of atomic momentum in the dispersive Jaynes-Cummings model

We present a theoretical scheme based on su(2) algebra to investigate the influence of homogeneous gravitational field on the quantum nondemolition measurement of atomic momentum in dispersive Jaynes-Cummings model. In the dispersive Jaynes-Cummings model, when detuning is large and the atomic motion is in a propagating light wave, we consider a two-level atom with quantized cavity-field in the presence of a homogeneous gravitational field. We derive an effective Hamiltonian describing the dispersive atom-field interaction in the presence of gravitational field. We can see gravitational influence both on the momentum filter and momentum distribution. Moreover, gravitational field decreases both tooth spacing of momentum and the width of teeth of momentum.Comment: 21 pages, 8 figure

On the Control of Microgrids Against Cyber-Attacks: A Review of Methods and Applications

Nowadays, the use of renewable generations, energy storage systems (ESSs) and microgrids (MGs) has been developed due to better controllability of distributed energy resources (DERs) as well as their cost-effective and emission-aware operation. The development of MGs as well as the use of hierarchical control has led to data transmission in the communication platform. As a result, the expansion of communication infrastructure has made MGs as cyber-physical systems (CPSs) vulnerable to cyber-attacks (CAs). Accordingly, prevention, detection and isolation of CAs during proper control of MGs is essential. In this paper, a comprehensive review on the control strategies of microgrids against CAs and its defense mechanisms has been done. The general structure of the paper is as follows: firstly, MGs operational conditions, i.e., the secure or insecure mode of the physical and cyber layers are investigated and the appropriate control to return to a safer mode are presented. Then, the common MGs communication system is described which is generally used for multi-agent systems (MASs). Also, classification of CAs in MGs has been reviewed. Afterwards, a comprehensive survey of available researches in the field of prevention, detection and isolation of CA and MG control against CA are summarized. Finally, future trends in this context are clarified

First record of Rhinogobius similis, Gill 1895 In Iran

This is the first record of Rhinogobius similis (Gobiidae), an exotic fish species in Iran. The results of this study show that a limited number of this species live in Harir-rud on Iran, Torkman Border. The morphometric and morphological characters of this species in Iran are similar to these from Japan and Korea