Using Contraflow on a Road Segment to Improve Emergency Response Vehicle Speed in a Connected Vehicle Environment

Emergency response vehicles (ERVs) need to reach their destinations as fast as possible. Road congestion and unpredictable movement of non-emergency vehicles (non-ERVs) makes it challenging for the ERV to move quickly. By using the autonomous/connected vehicle environment, instructions can be disseminated to the non-ERVs in the vicinity of the ERV to facilitate its passage within a link. In this thesis, an extension to a previously developed mathematical program is proposed to enable the ERV to use a contraflow lane when considerable speed gains can be potentially achieved. An experimental analysis is conducted to evaluate the sensitivity of the model’s output to traffic congestion, downstream non-ERV positions, ERV starting position, road composition, road segment length, and the length of the feasible stopping range for every non-ERV. Results showed that usage of contraflow was provided the least travel times for the ERV when it started in the left-most lane of the normal direction. Also, when the normal direction of the road was heavily congested as compared to the contraflow segment, the usage of contraflow by the ERV provided it the least travel times. In addition, a comparative study is performed to compare the proposed formulation with previously developed non-contraflow strategies as well as the currently adopted strategy requiring vehicles to move to the nearest edge. Results showed that the use of contraflow by the ERV provides improved travel times and average ERV speeds in many situations when the contraflow segment volume was sparse whereas the normal direction was congested. However, the computation times for the newly developed contraflow strategy were greater than the previously developed non-contraflow strategies. So, a heuristic was developed to reduce computational effort by cutting off the solver at a specified point, which was decided by how far the current feasible solution found was from the possible optimal solution (optimality gap). This heuristic not only provided improved computation times, but also results which did not statistically differ from the optimal results. The paths provided by the heuristic were also similar with the only difference being the points at which the lane changes happened. Hence, the utilization of this approach can potentially save lives due to reduced emergency response times

Biomedical applications of three‐dimensional bioprinted craniofacial tissue engineering

Abstract Anatomical complications of the craniofacial regions often present considerable challenges to the surgical repair or replacement of the damaged tissues. Surgical repair has its own set of limitations, including scarcity of the donor tissues, immune rejection, use of immune suppressors followed by the surgery, and restriction in restoring the natural aesthetic appeal. Rapid advancement in the field of biomaterials, cell biology, and engineering has helped scientists to create cellularized skeletal muscle‐like structures. However, the existing method still has limitations in building large, highly vascular tissue with clinical application. With the advance in the three‐dimensional (3D) bioprinting technique, scientists and clinicians now can produce the functional implants of skeletal muscles and bones that are more patient‐specific with the perfect match to the architecture of their craniofacial defects. Craniofacial tissue regeneration using 3D bioprinting can manage and eliminate the restrictions of the surgical transplant from the donor site. The concept of creating the new functional tissue, exactly mimicking the anatomical and physiological function of the damaged tissue, looks highly attractive. This is crucial to reduce the donor site morbidity and retain the esthetics. 3D bioprinting can integrate all three essential components of tissue engineering, that is, rehabilitation, reconstruction, and regeneration of the lost craniofacial tissues. Such integration essentially helps to develop the patient‐specific treatment plans and damage site‐driven creation of the functional implants for the craniofacial defects. This article is the bird's eye view on the latest development and application of 3D bioprinting in the regeneration of the skeletal muscle tissues and their application in restoring the functional abilities of the damaged craniofacial tissue. We also discussed current challenges in craniofacial bone vascularization and gave our view on the future direction, including establishing the interactions between tissue‐engineered skeletal muscle and the peripheral nervous system

Biomedical applications of three-dimensional bioprinted craniofacial tissue engineering.

Anatomical complications of the craniofacial regions often present considerable challenges to the surgical repair or replacement of the damaged tissues. Surgical repair has its own set of limitations, including scarcity of the donor tissues, immune rejection, use of immune suppressors followed by the surgery, and restriction in restoring the natural aesthetic appeal. Rapid advancement in the field of biomaterials, cell biology, and engineering has helped scientists to create cellularized skeletal muscle-like structures. However, the existing method still has limitations in building large, highly vascular tissue with clinical application. With the advance in the three-dimensional (3D) bioprinting technique, scientists and clinicians now can produce the functional implants of skeletal muscles and bones that are more patient-specific with the perfect match to the architecture of their craniofacial defects. Craniofacial tissue regeneration using 3D bioprinting can manage and eliminate the restrictions of the surgical transplant from the donor site. The concept of creating the new functional tissue, exactly mimicking the anatomical and physiological function of the damaged tissue, looks highly attractive. This is crucial to reduce the donor site morbidity and retain the esthetics. 3D bioprinting can integrate all three essential components of tissue engineering, that is, rehabilitation, reconstruction, and regeneration of the lost craniofacial tissues. Such integration essentially helps to develop the patient-specific treatment plans and damage site-driven creation of the functional implants for the craniofacial defects. This article is the bird's eye view on the latest development and application of 3D bioprinting in the regeneration of the skeletal muscle tissues and their application in restoring the functional abilities of the damaged craniofacial tissue. We also discussed current challenges in craniofacial bone vascularization and gave our view on the future direction, including establishing the interactions between tissue-engineered skeletal muscle and the peripheral nervous system

A Study of Scheduling Problems with Sequence Dependent Restrictions and Preferences

In some applications like fabric dying, semiconductor wafer processing, and flexible manufacturing, the machines being used to process jobs must be set up and serviced frequently. These setup processes and associated setup times between jobs often depend on the jobs and the sequence in which jobs are placed onto machines. That is, the scheduling of jobs on machines must account for the sequence-dependent setup times as well. These setup times can be a major factor in operational costs. In fabric dyeing processes, the sequence in which jobs are processed is also important for quality, i.e., there is a strong preference to run a certain type of job after another. There are also preferences associated with scheduling jobs on specific machines. Along with these preferences, there are also sequence-dependent restrictions, i.e., certain jobs are not allowed to immediately follow certain others on the same machine. In this dissertation, a mixed-integer linear programming (MILP) formulation is first developed to schedule jobs onto the machines while accounting for the setup times and the sequence-dependent restrictions. The newly introduced preferences have been modeled as two new objectives along with traditionally used objectives such as makespan, lateness, and total setup times. This MILP is found to be inadequate in solving some of the objectives. So, improvements are made to this formulation in the form of the addition of valid inequalities and solving some underlying separation problems to obtain tighter bounds. The different versions of the MILPs are compared for computational times and optimality gaps obtained on the multiple objectives. The improved MILPs perform significantly better on all objectives and hence are more usable as well. But, they also are found to be useful only for a certain level of problem sizes, beyond which their ability to obtain optimal solutions is severely hampered by the curse of dimensionality. To tackle larger problems, multiple construction heuristics have been developed/ adapted from literature. Some of these heuristics are basic job-placement rules like SPT (Shortest processing time) or EDD (earliest due date) which have been modified to handle the sequence-based restrictions and machine eligibility rules. Other construction heuristics have been developed to incorporate the newly introduced preferences. Next, a problem size breakdown method has been developed. This heuristic method incorporates a MILP to remove the fewest possible edges in the machine eligibility graph so that a larger problem can be broken down into independently solvable smaller problems solved to optimality. These heuristic methods are compared against the optimal solutions for small problems for solution quality on all five objectives. They are also compared against each other for larger problems. The MILP-based heuristic is also tested for computational performance. From the comparison results, it was seen that the methods developed so far are unable to tackle all the objectives simultaneously, and produce multiple solutions so that the user can evaluate trade-offs among the objectives. So, two popular multi-objective meta-heuristic frameworks have been adapted to tackle the new objectives as well as provide multiple Pareto-optimal solutions. Within each of the two methods, the job placement has been performed by two approaches: a construction heuristic approach and a semi-optimal approach. The two methods along with the two job placement approaches have been compared for computation times and quality of results. The best meta-heuristic methods are found to perform better than the construction heuristics on almost all objectives consistently, at the expense of more computational effort

A Pilot Study of Electrocardiographic Features in Patients with Obesity from a Tertiary Care Centre in Southern India (Electron)

Background: Obesity is associated with increased all-cause mortality and cardiovascular disease (CVD). An electrocardiogram (ECG) may be used to screen for subtle signs of CVD or altered cardiac morphology in the obese. Methodology: This observational cross-sectional analysed ECG changes in patients with obesity at a tertiary care centre in southern India. Results: One hundred and fifty adult patients with a mean (SD) BMI of 39.9 (6.7) kg/m2 were recruited in the study after excluding those with comorbidities (diabetes mellitus, systemic hypertension) or on chronic medications (ACE inhibitors). The cohort showed a female predominance (69.3%), with a mean (SD) age of 45.4 (11.2) years. Most patients exhibited a sinus rhythm (78%), with one patient showing features of first-degree conduction block. Sinus tachycardia was seen in 32 (21.3%) patients. We observed left and right ventricular hypertrophy in five (3.3%) and three (2%) patients, respectively. Observed ECG patterns included a prolonged QTc in 16 (10.7%) patients, inverted T-waves (mostly in the inferior leads) in 39 (26%) patients and ST-segment depression (predominantly in the lateral leads) in 14 (9.3%) patients. A greater prevalence was noted for morbid obesity. No deaths were reported in our cohort. Conclusions: The predominant ECG variations in this cohort included tachycardia, atrial enlargement, ventricular hypertrophy, conduction defects, LAD, features of ischemia or old infarction and repolarization abnormalities, with a greater prevalence in morbid obesity. Further studies are needed to assess the impact of weight reducing measures on reversibility of these changes and determine the association with outcomes in obese patients