Optimized routing of unmanned aerial systems to address informational gaps in counterinsurgency

Thesis (S.M. in Transportation)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 129-132).Recent military conflicts reveal that the ability to assess and improve the health of a society contributes more to a successful counterinsurgency (COIN) than direct military engagement. In COIN, a military commander requires maximum situational awareness not only with regard to the enemy but also to the status of logistical support concerning civil security operations, governance, essential services, economic development, and the host nation's security forces. Although current Brigade level Unmanned Aerial Systems (UAS) can provide critical unadulterated views of progress with respect to these Logistical Lines of Operation (LLO), the majority of units continue to employ UASs for strictly conventional combat support missions. By incorporating these LLO targets into the mission planning cycle with a collective UAS effort, commanders can gain a decisive advantage in COIN. Based on the type of LLO, some of these targets might require more than a single observation to provide the maximum benefit. This thesis explores an integer programming and metaheuristic approach to solve the Collective UAS Planning Problem (CUPP). The solution to this problem provides optimal plans for multiple sortie routes for heterogeneous UAS assets that collectively visit these diverse secondary LLO targets while in transition to or from primary mission targets. By exploiting the modularity of the Raven UAS asset, we observe clear advantages, with respect to the total number of targets observed and the total mission time, from an exchange of Raven UASs and from collective sharing of targets between adjacent units. Comparing with the status quo of decentralized operations, we show that the results of this new concept demonstrate significant improvements in target coverage. Furthermore, the use of metaheuristics with a Repeated Local Search algorithm facilitates the fast generation of solutions, each within 1.72% of optimality for problems with up to 5 UASs and 25 nodes. By adopting this new paradigm of collective Raven UAS operations and LLO integration, Brigade level commanders can maximize the use of organic UAS assets to address the complex information requirements characteristic of COIN. Future work for the CUPP to reflect a more realistic model could include the effects of random service times and high priority pop-up targets during mission execution.by Andrew C. Lee.S.M.in Transportatio

Rheological techniques for determining degradation of polylactic acid in bioresorbable medical polymer systems

© 2015 AIP Publishing LLC. A method developed in the 1980s for the conversion of linear rheological data to molar mab distribution is revisited in the context of degradable polymers. The method is first applied using linear rheology for a linear polystyrene, for which all conversion parameters are known. A proof of principle is then carried out on four polycarbonate grades. Finally, preliminary results are shown on degradable polylactides. The application of this method to degrading polymer systems, and to systems containing nanofillers, is also discubed. This work forms part of a wider study of bioresorbable nanocomposites using polylactides, novel hydroxyapatite nanoparticles and tailored dispersants for medical applications

Heparanase and autoimmune diabetes

Heparanase (Hpse) is the only known mammalian endo-β-d-glucuronidase that degrades the glycosaminoglycan heparan sulfate (HS), found attached to the core proteins of heparan sulfate proteoglycans (HSPGs). Hpse plays a homeostatic role in regulating the turnover of cell-associated HS and also degrades extracellular HS in basement membranes (BMs) and the extracellular matrix (ECM), where HSPGs function as a barrier to cell migration. Secreted Hpse is harnessed by leukocytes to facilitate their migration from the blood to sites of inflammation. In the non-obese diabetic (NOD) model of autoimmune Type 1 diabetes (T1D), Hpse is also used by insulitis leukocytes to solubilize the islet BM to enable intra-islet entry of leukocytes and to degrade intracellular HS, an essential component for the survival of insulin-producing islet beta cells. Treatment of pre-diabetic adult NOD mice with the Hpse inhibitor PI-88 significantly reduced the incidence of T1D by ~50% and preserved islet HS. Hpse therefore acts as a novel immune effector mechanism in T1D. Our studies have identified T1D as a Hpse-dependent disease and Hpse inhibitors as novel therapeutics for preventing T1D progression and possibly the development of T1D vascular complications.This work was supported by a National Health and Medical Research Council of Australia (NHMRC)/Juvenile Diabetes Research Foundation (JDRF) Special Program Grant in Type 1 Diabetes (#418138), a NHMRC Project Grant (#1043284), and a research grant from the Roche Organ Transplantation Research Foundation (ROTRF)/JDRF (#477554991)

An investigation into unusual access sites for arterial endovascular interventions

The endovascular revolution has transformed clinical practice with significant benefits to patients, in particular, as minimally invasive treatment options for those who would have previously been deemed inoperable by conventional ‘open’ surgical techniques. However, it is impossible to perform arterial endovascular interventions without accessing the arterial system first. Despite close to 100 years of technological and procedural improvement, the femoral artery remains the gold standard arterial access site. In those patients where femoral arterial access is contraindicated, alternative access sites have been described. The majority of these access sites are standard alternatives and are already used in routine clinical practice. However, other arterial access sites are more unusual, and their use is potentially more harmful to patients than standard access. As a vascular, endovascular and aortic surgeon, I have a varied practice that ranges from traditional open surgery to arterial endovascular interventions, creating alternative vascular access for other specialties who may require it and also repairing the complications arising from vascular access as well. I remain keen to maximise the benefits of endovascular surgery for all my patients, even if femoral arterial access is contraindicated. This led me to investigate unusual arterial access sites for arterial endovascular interventions. Some of the early descriptions in the literature of unusual access sites for arterial endovascular interventions were not just radical but potentially significantly harmful to patients. A lack of pooled contemporary evidence was sorely lacking, and I embarked on this body of work to fill that evidence gap. My ultimate aim was to educate myself and my colleagues who may also require unusual access sites in their clinical practice, whilst keeping patient safety at the forefront and of paramount importance

Peripheral primitive neuroectodermal tumour - A rare cause of a popliteal fossa mass: A case report and review of the literature

A literature review of peripheral primitive neuroectodermal tumours, illustrated with an index case report describing an 80-year-old woman who presented with a mass in the left popliteal fossa, is reported. An excision biopsy was performed, revealing a possible peripheral primitive neuroectodermal tumour as the primary pathology. Normally confined to the chest wall and axial soft tissues of children and young adults, reports of this tumour existing in other areas and in the elderly population are scarce

Compounding and rheometry of PLA nanocomposites with coated and uncoated hydroxyapatite nanoplatelets

Polylactic acid and novel nanoplatelets of hydroxyapatite (HANP) were compounded in a laboratory scale twin-screw extruder and injection moulded to shape. The effect of HANP loading content, between 1 wt% and 10 wt%, and of HANP surface coating with tailored molecular dispersants, on the processability and rheological behaviour were investigated. Dispersion of HANP within the matrix system was determined qualitatively using transmission electron micrographs. Surface coating of HANP with dispersants was observed to change the state of HANP dispersion in the nanocomposites. This was also reflected in the changes of the nanocomposites’ rheological response with the moduli of coated HANP systems increasing at lower frequencies

Long-term Periodicities of Cataclysmic Variables with Synoptic Surveys

A systematic study on the long-term periodicities of known Galactic cataclysmic variables (CVs) was conducted. Among 1580 known CVs, 344 sources were matched and extracted from the Palomar Transient Factory (PTF) data repository. The PTF light curves were combined with the Catalina Real-Time Transient Survey (CRTS) light curves and analyzed. Ten targets were found to exhibit long-term periodic variability, which is not frequently observed in the CV systems. These long-term variations are possibly caused by various mechanisms, such as the precession of the accretion disk, hierarchical triple star system, magnetic field change of the companion star, and other possible mechanisms. We discuss the possible mechanisms in this study. If the long-term period is less than several tens of days, the disk precession period scenario is favored. However, the hierarchical triple star system or the variations in magnetic field strengths are most likely the predominant mechanisms for longer periods.Comment: 33 pages, 9 figures (manuscript form), Accepted for publication in PAS