Solutions to trajectory optimization problems are carried out by the direct and indirect methods. Under broad heading of these methods, numerous algorithms such as collocation, direct, indirect and multiple shooting methods have been developed and reported in the literature. Each of these algorithms has certain advantages and limitations. For example, direct shooting technique is not suitable when the number of nonlinear programming variables is large. Indirect shooting method requires analytical derivatives of the control and co-states function and a poorly guessed initial condition can result in numerical unstable values of the adjoint variable. Multiple shooting techniques can alleviate some of these difficulties by breaking down the trajectory into several segments that help in reducing the non-linearity effects of early control on later parts of the trajectory. However, multiple shooting methods then have to handle more number of variables and constraints to satisfy the defects at the segment joints. The sie of the nonlinear programming problem in the collocation method is also large and proper locations of grid points are necessary to satisfy all the path constraints. Stochastic methods such as Genetic algorithms, on the other hand, also require large number of function evaluations before convergence. To overcome some of the limitations of the conventional methods, improved solution techniques are developed. Three improved methods are proposed for the solution of trajectory optimization problems. They are • a genetic algorithm employing dominance and diploidy concept. • a collocation method using chebyshev polynomials , and • a hybrid method that combines collocation and direct shooting technique A conventional binary-coded genetic algorithm uses a haploid chromosome, where a single string contains all the variable information in the coded from. A diploid, as the name suggests, uses pair of chromosomes to store the same characteristic feature. The diploid genetic algorithm uses a dominant map for decoding genotype into a stable, consistent phenotype. In dominance, one allele takes precedence over another. Diploidy and dominance helps in retaining the previous best solution discovered and shields them from harmful selection in a changing environment. Hence, diploid and dominance affect a king of long-term memory in the genetic algorithm. They allow alternate solutions to co-exist. One solution is expressed and the other is held in abeyance. In the improved diploid genetic algorithm, dominant and recessive genes are defined based on the fitness evaluation of each string. The genotype of fittest string is declared as the dominant map. The dominant map is dynamic in nature as it is replaced with a better individual in future generations. The concept of diploidy and dominance in the improved method mimics closer to the principles used in human genetics as compared to any such algorithms reported in the literature. It is observed that the improved diploid genetic algorithm is able to locate the optima for a given trajectory optimization problem with 10% lower computational time as compared to the haploid genetic algorithm. A parameter optimization problem arising from an optimal control problem where states and control are approximated by piecewise Chebyshev polynomials is well known. These polynomials are more accurate than the interpolating segments involving equal spaced data. In the collocation method involving Chebyshev polynomials, derivatives of two neighboring polynomials are matched with the dynamics at the nodal points. This leads to a large number of equality constraints in the optimization problem. In the improved method, derivative of the polynomial is also matched with the dynamics at the center of segments. Though is appears the problem size is merely increased, the additional computations improve the accuracy of the polynomial for a larger segment. The implicit integration step size is enhanced and overall size of the problem is brought down to one-fourth of the problem size defined with a conventional collocation method using Chebyshev polynomials. Hybrid method uses both collocation and direct shooting techniques. Advantages of both the methods are combined to give more synergy. Collocation method is used in the starting phase of the hybrid method. The disadvantage of standalone collocation method is that tuning of grid points is required to satisfy the path constraints. Nevertheless, collocation method does give a good guess required for the terminal phase of the hybrid method, which uses a direct shooting approach. Results show nearly 30% reduction in computation time for the hybrid approach as compared to a method in which direct shooting alone is used, for the same initial guess of control. The solutions obtained from the three improved methods are compared with an indirect method. The indirect method requires derivations of the control and adjoint equations, which are difficult and problem specific. Due to sensitivity of the costate variables, it is often difficult to find a solution through the indirect method. Nevertheless, these methods do provide an accurate result, which defines a benchmark for comparing the solutions obtained through the improved methods. Trajectory design and optimization of a RLV(Reusable Launch Vehicle) Demonstrator mission is considered as a test problem for evaluating the performance of the improved methods. The optimization problem is difficult than a conventional launch vehicle trajectory optimization problem because of the following two reasons. • aerodynamic lift forces in the RLV add one more dimension to the already complex launch vehicle optimization problem. • as RLV performs a sub orbital flight, the ascent phase trajectory influences the re-entry trajectory. Both the ascent and re-entry optimization problem of the RLV mission is addressed. It is observed that the hybrid method gives accurate results with least computational effort, as compared with other improved techniques for the trajectory optimization problem of RLV during its ascent flight. Hybrid method is then successfully used during the re-entry phase and in designing the feasible optimal trajectories under the dispersion conditions. Analytical solutions obtained from literature are used to compare the optimized trajectory during the re-entry phase. Trajectory optimization studies are also carried out for the off-nominal performances. Being a thrusting phase, the ascent trajectory is subjected to significant deviations, mainly arising out of solid booster performance dispersions. The performance index during rhe ascent phase is modified in a novel way for handling dispersions. It minimizes the state errors in a least square sense, defined at the burnout conditions ensure possibilities of safe re-entry trajectories. The optimal trajectories under dispersion conditions serve as a benchmark for validating the closed-loop guidance algorithm that is developed for the ascent phase flight. Finally, an on-line trajectory command-reshaping algorithm is developed which meets the flight objectives under the dispersion conditions. The guidance algorithm uses a pre-computed trajectory database along with some real-time measured parameters in generating the optimal steering profiles. The flight objectives are met under the dispersion conditions and the guidance generated steering profiles matches closely with the optimal trajectories.

L’augmentation rapide de l’interdépendance mondiale, provoquée par le développement de la mondialisation, exige une redéfinition de la notion traditionnelle de l’éducation supérieure. Au Canada, comme dans le reste du monde, plusieurs universitaires, fonctionnaires du gouvernement et étudiants insistent maintenant sur l’intégration de l’internationalisation dans l’éducation supérieure à travers des échanges interculturels et des études à l’étranger, dans l’espoir que les générations canadiennes à venir développent une perspective globale et deviennent des « citoyens du monde » (Comité consultatif sur la stratégie du Canada en matière d’éducation internationale, 2012). Pourtant, pour garantir que l’étudiant qui participe à un échange profite le plus de son expérience internationale, nous devrons comprendre comment une telle expérience l’influence tant à court terme qu’à long terme. Bien que d’autres études se soient concentrées sur le court terme (le séjour à l’étranger et ses impacts immédiats), peu ont examiné le retour de l’étudiant, sa réintégration dans sa société d’origine et les effets subséquents à long terme, tels que les développements personnels qui pourraient suivre le rapatriement. Cette étude qualitative examine les témoignages de huit étudiants au premier cycle de l’Université de Montréal sur la façon dont ils ont vécu leur rapatriement à Montréal après un échange pédagogique à l’étranger. Quoique certains chercheurs présentent la notion de rapatriement comme une série d’événements déconnectés, notre analyse fait ressortir une tendance similaire dans tous nos témoignages qui nous permet dorénavant de considérer ce rapatriement comme un processus en trois étapes interconnectées. En empruntant à la théorie Intercultural Personhood de Kim (2008), nous sommes désormais en mesure de qualifier ces trois étapes comme étant le stress, l’adaptation et l’évolution. Non seulement cette interprétation nous aide à mieux comprendre les difficultés rencontrées par l’étudiant à l’occasion de son retour, mais elle facilite également l’identification des transformations identitaires qui apparaissent à ce moment-là et la manière dont ces transformations influencent le processus de rapatriement. / The rapidly increasing interconnectedness of the world brought on by the expansion of globalization calls for a redefinition of the traditional notion of higher education. As such, many Canadian educators, government officials, and students alike are insisting on the importance of internationalizing higher education through intercultural exchanges and studying abroad, in the hopes that current and future generations of Canadians will acquire a global perspective and become citizens of the world (Advisory Panel on Canada’s International Education Strategy, 2012). Yet in order to ensure that students are gaining the most from their international experience, it is important to understand the impact that studying abroad can have, both in the short and long term. While many past studies have focused on the short-term, or the actual time spent abroad and subsequent impacts, few have examined the exchange student’s re-entry into their society of origin and subsequent long-term effects, such as personal developments that surface during repatriation. In this qualitative study, eight undergraduate students from the University of Montreal were interviewed regarding how they lived their reintegration into Montreal society after returning home post studying abroad. While academics that have broached the subject in the past tended to view repatriation as a static series of events, our data analysis showed a similar pattern that surfaced in all respondents’ testimonials allowing us to henceforth recognize this repatriation as an interconnected three-step process. By borrowing from Kim’s theory of Intercultural Personhood (2008), we are now able to define these three distinct phases as stress, adaptation, and growth; all of which not only help to better understand the difficulties students face during their process of reintegration but also facilitate the identification of possible identity transformations that surface upon re-entry and how these transformations impact the repatriation process.

The current context of offender health in England and Wales indicates that offenders re-enter their communities with limited pre-release preparation for the continuity of access to healthcare and an increased risk of release with a health condition and very little support to cope in the community. This study was aimed at mapping the ex-offender health pathway towards identifying ‘touch points’ in the community for the delivery of a nurse led intervention. The study was a qualitative case study underpinned by ‘The Silences Framework’ which enabled it to gain theoretically by situating power with offenders, thus, aiding their ‘Silences’ to be heard, explored and brought to light. Participants meeting the study inclusion criteria were quantitatively ranked on the basis of poor health with those scoring the lowest and confirming their ranking through a confirmation of a health condition selected as cases and interviewed over the course of six months. These interview narratives were confirmed by interviewing individuals in the professional networks of offenders. The study identified the site of post-release supervision as the ‘touch point’ where a nurse led intervention could be delivered. With regards to the delivery of the health intervention, the study indicated that the nurse led intervention be provided as an advisory and signposting service structured on a drop-in and appointment basis. Furthermore, the study indicated that pre-release, offenders were not prepared in prison for the continuity in access to healthcare in the community on release. On-release, offenders’ on-release preparation did not enquire as a matter of procedure on whether offenders were registered with a GP or had the agency to register self with a GP practice in the community. Post release, the study uncovered a disparity between services which address the physical health needs of offenders and those which address their mental and substance misuse health needs.

Urodele amphibians have the remarkable ability to re-grow lost body parts. This regenerative response after injury in urodeles involves dedifferentiation of fully differentiated cells into proliferative cells. One well-studied example of this is the dedifferentiation of multinucleated muscle cells into mononucleate cells resembling their precursors, the myoblasts. To form these mononucleate cells the differentiated myotubes in vivo must re-enter and complete the cell cycle; they again proliferate and produce progeny. A key question is what factors induce the myotubes to re-enter the cell cycle and proliferate. Early events of cell cycle re-entry can be studied in the A1 cell line, a myogenic cell line isolated from the Notophthalmus viridescens hindlimb, which traverses cell cycle until G2 in response to serum. In particular, it was found that thrombin cleavage induces a factor in serum of all animals tested so far to promote S phase re-entry in A1 myotubes. We have used this S phase re-entry of the A1 cell line to purify the serum activity and developed a 5-step purification protocol that enriches the activity almost 2 000 fold over the starting material, or 40 000 fold over serum. To conveniently produce and test potential candidates for their ability to induce S phase re-entry in A1 myotubes, we also developed an overexpression- and purification system for emerging candidates. Candidates were then tested for this activity with or without prior incubation with thrombin. We identified Bmp proteins as the first pure molecules that were found in fractions across the purification of the activity and that could also induce cell cycle re-entry in a dose-dependent manner when recombinantly added to the A1 myotubes. Furthermore, this response could be blocked in a dose-dependent manner by the known bmp-inhibitor noggin. Finally, we showed that inhibition of Bmp signaling in vivo causes defects in axolotl tail regeneration.

Peer-to-peer (P2P) reputation systems, such as those used by eBay and Amazon, servean important role on the web, especially in E-commerce, as online reputation serves asa primary guiding factor for consumers in making informed decisions. The importanceof these systems, and also the increasing popularity of P2P and distributed systems, theissue of how to prevent and resist sybil and re-entry attacks becomes an important area ofresearch as they can impinge the integrity of those systems. To address this issue, in thisthesis, we propose an approach that encompasses a software architecture and processeswhich serves as a proof-of-concept of how to mitigate sybil and re-entry attacks on review based P2P distributed reputation systems. The architecture uses novel technologiessuch as blockchain, smart contracts, and non-fungible tokens (NFT) in conjunction withSwedish E-id provider BankID to build a sybil and re-entry attack resistant reputationsystem. To validate the feasibility of our approach, we developed a prototype and used itto run experiments to evaluate the functional correctness of the architecture as a mitigation solution

Over 42% of students re-entering education in the United States are age 24 or older (NCES, 2002). Community colleges offer financial, academic, and geographic accessibility making them a viable option for adults seeking to re-enter education (Cohen & Brawer, 1996). The purpose of this study was to learn more about the life transitions that precipitate entry into a community college. The researcher also sought to bring insights about the experiences of being an adult student returning to education at a community college. Research participants included 24 adult re-entry students and recent graduates at Mountain Empire Community College in Big Stone Gap, Virginia. Through indepth interviews, the personal experiences of the life transitions that prompted college entrance and the experience of being enrolled in college were explored. Qualitative research techniques were used in this study. Interviews were tape recorded and transcribed. The findings derived from the data analysis were presented thematically as they addressed the research questions. The findings revealed that participants returned to education because of job-related concerns (typically a layoff or company's closing) or an issue of timing (a feeling that it was "time" to return). Re-entry students faced barriers that were both institutional and personal as they navigated the educational process. Participants reported that financial, geographic, and academic accessibility of the college made it a resource in itself. Finally, participants suggested implementing a specialized, adult, student-focused orientation course, on-site daycare services, and campus activities supportive of needs of students returning to the academic world. Recommendations included a quantitative study involving a survey with a larger sample of adult re-entry students. The data could provide a richer examination of the similarities and differences among the re-entry college population. Recommendations for practice included an orientation class specifically designed to attract and meet the needs of adult re-entry students at the community college level; the establishment of a comprehensive, developmentally-based childcare service located on the college campus; and initial and follow-up contacts by a counselor designated as an adult, re-entry student contact and resource person in the student services division.

Purpose: To evaluate the use of the GoBack-catheter (Upstream Peripheral Technologies) in complex revascularizations in lower limb arteries. Materials and Methods: In this retrospective single-center study, the results of the first 100 consecutive patients including 101 limb-revascularizations, performed between May 2018 and July 2020 with the study device, were analyzed. In all cases, guidewire-crossing failed, and all lesions were chronic total occlusions (CTO), either de novo, reocclusions, or in-stent reocclusions. Successful crossing was defined as passing the CTO using the study device. Patency at discharge and after 30 days was defined as less than 50% restenosis on duplex sonography, without target lesion revascularization. Results: Median lesion length was 24 cm and 38 patients (37.6%) had a calcium grading according to the peripheral arterial calcium scoring system (PACSS) of 4 or 5. In 20.8% of patients, an occluded stent was treated. CTOs involved the femoropopliteal segment in 91.1%, iliac arteries in 5.9%, and tibial arteries in 7.9%. The GoBackcatheter was employed for entering into or crossing through parts or the full length of a CTO or an occluded stent as well as for re-entering into the true lumen after subintimal crossing. The device was used via contralateral and ipsilateral antegrade as well as retrograde access with an overall technical success rate of 92.1%. In 3 patients minor bleeding occurred at the crossing or re-entry site, which were managed conservatively. Thirty-day adverse limb events comprised minor amputations in 4 patients (4.0%), 1 major amputation (1.0%), and reocclusions in 7 limbs (6.9%). Conclusion: The new GoBack-catheter offers versatile endovascular applicability for complex CTO recanalization in a broad range of peripheral vascular interventions with a high technical success and low complication rate.

Thesis (LLM.) -- University of Limpopo, 2022 / The study will analyse the legal position of the right to strike and the consequences of participating in an unlawful strike. The study will provide a brief practical implication of employees dismissed for participation in an unlawful and/or unprotected strike and the employer’s right to reemploy any employee dismissed for a misconduct relating to unlawful and/or unprotected strike. The study will further make a brief comparison with the labour law position relating to strikes in the United Kingdom (“UK”). At the end provide recommendations on how the law on participation on unlawful and/or unprotected strikes and reemployed of employees dismissed on misconduct relating to participation in an unprotected strike can be developed and improved.

No description available.

No description available.