En astronautique, une question importante est de contrôler le mouvement d’un satellite soumis à la gravitation des corps célestes de telle sorte que certains indices de performance soient minimisés (ou maximisés). Dans cette thèse, nous nous intéressons à la minimisation de la norme L¹ du contrôle pour le problème circulaire restreint des trois corps. Les conditions nécessaires à l’optimalité sont obtenues en utilisant le principe du maximum de Pontryagin, révélant l’existence de contrôles bang-bang et singuliers. En s’appuyant sur les résultats de Marchal [1] et Zelikin et al. [2], la présence du phénomène de Fuller est mise en évidence par l’analyse des es extrêmales singulières. La contrôlabilité pour le problème à deux corps (un cas dégénéré du problème circulaire restreint des trois corps) avec un contrôle prenant des valeurs dans une boule euclidienne est caractérisée dans le chapitre 2. Le résultat de contrôlabilité est facilement étendu au problème des trois corps puisque le champ de vecteurs correspondant à la dérive est récurrent. En conséquence, si les trajectoires contrôlées admissibles restent dans un compact fixé, l’existence des solutions du problème de minimisation L¹ peut être obtenu par une combinaison du théorème de Filippov (voir [4, chapitre 10]) et une procédure appropriée de convexification (voir [5]). En dimension finie, le problème de minimisation L¹ est bien connu pour générer des solutions où le contrôle s’annule sur certains intervalles de temps. Bien que le principe du maximum de Pontryagin soit un outil puissant pour identifier les solutions candidates pour le problème de minimisation L¹, il ne peut pas garantir que ces candidats sont au moins localement optimaux sauf si certaines conditions d’optimalité suffisantes sont satisfaites. En effet, il est une condition préalable pour établir (et pour être capable de vérifier) les conditions d’optimalité nécessaires et suffisantes pour résoudre le problème de minimisation L¹. Dans cette thèse, l’idée cruciale pour obtenir de telles conditions est de construire une famille paramétrée d’extrémales telle que l’extrémale de référence peut être intégrée dans un champ d’extrémales. Deux conditions de non-pliage pour la projection canonique de la famille paramétrée d’extrémales sont proposées. En ce qui concerne le cas de points terminaux fixés, ces conditions de non-pliage sont suffisantes pour garantir que l’extrémale de référence est localement minimisante tant que chaque point de commutation est régulier (cf. chapitre 3). Si le point terminal n’est pas fixe mais varie sur une sous-variété lisse, une condition suffisante supplémentaire impliquant la géométrie de variété de cible est établie (cf. chapitre 4). Bien que diverses méthodes numériques, y compris celles considérées comme directes [6, 7], indirectes [5, 8], et hybrides [11], dans la littérature sont en mesure de calculer des solutions optimales, nous ne pouvons pas attendre d’un satellite piloté par le contrôle optimal précalculé (ou le contrôle nominal) de se déplacer sur la trajectoire optimale précalculée (ou trajectoire nominale) en raison de perturbations et des erreurs inévitables. Afin d’éviter de recalculer une nouvelle trajectoire optimale une fois que la déviation de la trajectoire nominale s’est produite, le contrôle de rétroaction optimale voisin, qui est probablement l’application pratique la plus importante de la théorie du contrôle optimal [12, Chapitre 5], est obtenu en paramétrant les extrémales voisines autour de la nominale (cf. chapitre 5). Étant donné que la fonction de contrôle optimal est bang-bang, le contrôle optimal voisin comprend non seulement la rétroaction sur la direction de poussée, mais aussi celle sur les instants de commutation. En outre, une analyse géométrique montre qu’il est impossible de construire un contrôle optimal voisin une fois que le point conjugué apparaisse ou bien entre ou bien à des instants de commutation. / In astronautics, an important issue is to control the motion of a satellite subject to the gravitation of celestial bodies in such a way that certain performance indices are minimized (or maximized). In the thesis, we are interested in minimizing the L¹-norm of control for the circular restricted three-body problem. The necessary conditions for optimality are derived by using the Pontryagin maximum principle, revealing the existence of bang-bang and singular controls. Singular extremals are analyzed, and the Fuller phenomenon shows up according to the theories developed by Marchal [1] and Zelikin et al. [2, 3]. The controllability for the controlled two-body problem (a degenerate case of the circular restricted three-body problem) with control taking values in a Euclidean ball is addressed first (cf. Chapter 2). The controllability result is readily extended to the three-body problem since the drift vector field of the three-body problem is recurrent. As a result, if the admissible controlled trajectories remain in a fixed compact set, the existence of the solutions of the L¹-minimizaion problem can be obtained by a combination of Filippov theorem (see [4, Chapter 10], e.g.) and a suitable convexification procedure (see, e.g., [5]). In finite dimensions, the L¹-minimization problem is well-known to generate solutions where the control vanishes on some time intervals. While the Pontryagin maximum principle is a powerful tool to identify candidate solutions for L1-minimization problem, it cannot guarantee that the these candidates are at least locally optimal unless sufficient optimality conditions are satisfied. Indeed, it is a prerequisite to establish (as well as to be able to verify) the necessary and sufficient optimality conditions in order to solve the L¹-minimization problem. In this thesis, the crucial idea for establishing such conditions is to construct a parameterized family of extremals such that the reference extremal can be embedded into a field of extremals. Two no-fold conditions for the canonical projection of the parameterized family of extremals are devised. For the scenario of fixed endpoints, these no-fold conditions are sufficient to guarantee that the reference extremal is locally minimizing provided that each switching point is regular (cf. Chapter 3). If the terminal point is not fixed but varies on a smooth submanifold, an extra sufficient condition involving the geometry of the target manifold is established (cf. Chapter 4). Although various numerical methods, including the ones categorized as direct [6, 7], in- direct [5, 8, 9], and hybrid [10], in the literature are able to compute optimal solutions, one cannot expect a satellite steered by the precomputed optimal control (or nominal control) to move on the precomputed optimal trajectory (or nominal trajectory) due to unavoidable perturbations and errors. In order to avoid recomputing a new optimal trajectory once a deviation from the nominal trajectory occurs, the neighboring optimal feedback control, which is probably the most important practical application of optimal control theory [11, Chapter 5], is derived by parameterizing the neighboring extremals around the nominal one (cf. Chapter 5). Since the optimal control function is bang-bang, the neighboring optimal control consists of not only the feedback on thrust direction but also that on switching times. Moreover, a geometric analysis shows that it is impossible to construct the neighboring optimal control once a conjugate point occurs either between or at switching times.

Summary This study deals with Jesus and the outsiders in John 4, with particular focus on John 4:1-42. Methodologically, the study focuses on social identity theory, and asks the question of how Jesus gets the Samaritan woman, who is a member of the outside group, into the insider group. The focus of the study is thus what the behaviour and attitude of the historical and non-conventional Jesus, in the strongly hierarchical social structure of his day, was toward outsiders. John 4:1-42 is often used in works that focus on missional tendencies in the church. This research attempts to place the missionary responsibility of the church on the table in a new light, resulting from the research results. Firstly, the inter-relational connection between identity, ethos and ethics with regard to Jesus’ attitude toward the outsiders in John 4:1-42 is researched. Secondly, the interpretation history of John is described, whereafter the social-scientific approach and the way in which social identity theory can be applied to John 4:1-42, is described. The purpose of the study is to suggest a new missional approach for the church, based on the research results of the study. In John 4:1-42 Jesus did not only repair the relationship between Him as a Jew and the Samaritan woman, but also the broken relationship between the Samaritans and the Jews - two previously conflicting ethnic groups who are now born into the new family of God (John 1:12). In the narrative, the Samaritan woman becomes a μαρτυρούσης (John 4:39). The result of the Samaritan woman’s testimony (John 4:39) becomes a personal testimony that eventually convinces the others of Jesus’ true identity (John 4:39). The woman’s testimony provided the initial impetus for them to come to Jesus, but now they have heard for themselves and have drawn their own conclusion. Many had believed in Jesus on account of the Samaritan woman’s testimony. Many more believed on account of Jesus’ word. Jesus’ harvest among the Samaritans therefore signals the return of a part of the unbelieving world to God as a first sign of the universal scope of Jesus’ saving mission. / Thesis (PhD)-- University of Pretoria 2017. / New Testament Studies / PhD / Unrestricted

As virtual reality and interaction possibilities in game technology evolve and become more user-friendly, accessible and cheaper, this technology suddenly gets useful in occupational areas that traditionally have not used them, one being urban planning. By using a game engine and a virtual neighborhood that utilizes procedural generation the user has the option of having a cost-effective, replicable environment with great control from the user.  According to the Broken Windows Theory small differences in appearance can have a big impact on how an urban neighborhood will be perceived. Therefore it would be interesting to investigate how the perception of street scenes is affected by the different aesthetic properties of dirt, graffiti, broken windows, building height and greenery (trees and bushes). By implementing a virtual neighborhood that utilizes procedural generation the basic structure of the neighborhood can stay the same, while separately adjusting the specific properties that are being evaluated. Through surveys and interviews the results show that every one of the chosen properties are very significant except for building height. Generally the more trees that were present, the more safe the neighborhood felt, and the order of significance of dirt, graffiti and broken windows differed between the two evaluation methods. / Då virtual reality och interaktionsmöjligheterna inom spelteknologi utvecklas och blir mer användarvänliga, mer tillgängliga och billigare, blir denna teknik plötsligt användbar inom yrkesområden som traditionellt sett inte har använt dem, där ett exempel är stadsplanering. Genom att använda en spelmotor och en virtuell stadsdel som utnyttjar procedural generation får användaren en kostnadseffektiv, replikerbar miljö med stor kontroll från användaren. Enligt Broken Windows Theory så kan små skillnader i utseende ha en stor inverkan på hur en stadsdel kommer att uppfattas. Därför vore det intressant att undersöka hur synen på virtuella gatscener påverkas av olika estetiska egenskaper som smuts, graffiti, trasiga fönster, bygghöjd, och grönska (träd och buskar). Genom att implementera en virtuell stadsdel som utnyttjar procedural generation kan grundstrukturen vara densamma, medan man separat justerar de specifika egenskaperna som ska utvärderas. Genom enkäter och intervjuer visar resultaten att var och en av de valda egenskaperna är mycket betydande, med undantaget för byggnadshöjd. Generellt så kändes stadsdelen mer säker desto mer träd som fanns, och ordningen av signifikansen för smuts, graffiti, och trasiga fönster skiljde sig mellan enkäterna och intervjuerna.

Context:Broken heart syndrome or Takotsubo cardiomyopathy (TC) is a disorder characterized by transient left ventricular apical ballooning that almost invariably precedes emotional or physical stress. Although the patients with chronic kidney disease on hemodialysis have shown to exhibit sustained activity of sympathetic nervous system, the presentation of TC in these patients is a rare entity with few case reports in the literature. Case Report: A 75-year-old female with past medical history of end-stage renal disease presented with chest pressure and heaviness that started during her maintenance hemodialysis session. Electrocardiogram showed ST elevation and T wave inversion in V3-V6 leads. Emergent left heart catheterization was done that showed normal coronaries and akinesis of apical left ventricle wall consistent with TC. She was started on maximal medical management and underwent hemodialysis the next day without recurrence of the symptoms. Conclusion: TC may an underdiagnosed entity in patients on hemodialysis. However, it should be considered in the differential diagnosis in hemodialysis patients, particularly who presents with chest pain and/or symptoms.

No description available.

Law enforcement agencies believe that traffic enforcement, in addition to reducing fatalities associated with automobile collisions, may also reduce the incidence of public order crimes. The academic literature, though, has largely failed to address this phenomenon. The purpose of this correlational study was to use Kelling and Wilson's broken windows theory to evaluate whether a statistically significant relationship exists between traffic enforcement rates and public order crimes in South Carolina. Secondary data from 5 counties were acquired from the South Carolina Department of Public Safety and the South Carolina Law Enforcement Division for the time period 2008 through 2012. Statistically significant Spearman's Rho correlations were found for 4 of the 5 counties (p < .05). Though statistically significant, the correlations were weak. The findings suggest that Wilson and Kelling's theory is somewhat predictive of the relationship between the visibility of law enforcement officers and reductions in public order crimes, but may not fully explain this relationship. Even so, there is some evidence that the presence of traffic enforcement officers may reduce certain types of crime, thereby improving the quality of life for residents. Based on the findings, one important recommendation of this study is for law enforcement agencies in South Carolina to consider enhancing or expanding the use of traffic enforcement teams because of their potential value in reducing public order crimes, including a plan to conduct a follow-up evaluation of the efficacy of such a program.

De senaste 25 åren har regeringen presenterat två nationella brottsförebyggande program som i stora delar delegerar ansvaret för det brottspreventiva arbetet till landets kommuner, ett ansvar som dock inte är lagstadgat. Denna uppsats undersöker Härryda kommuns brottsförebyggande arbete ur ett situationellt perspektiv. Undersökningens syfte är att öka kunskapen om hur en kommun lokalt implementerar de nationella riktlinjerna om förebyggande åtgärder som förordas i de brottsföre- byggande programmen Allas vårt ansvar (1996) och Tillsammans mot brott (2017). Med utgångs- punkt från kriminologiska teorier och tidigare forskning om situationell brottsprevention, bland annat rutinaktivitetsteorin, broken windows, och antaganden om begreppet governance, besvarar uppsatsen frågeställningarna ”vilka situationella brottsförebyggande åtgärder prioriterar Härryda kommun, och varför?”, ”hur utvärderas de brottsförebyggande insatserna, och vilka möjligheter eller begränsningar ser centrala brottsförebyggande aktörer i kommunens situationella brottsföre- byggande arbete?” samt ”hur förstås och konstrueras begreppen trygghet och otrygghet i relation till situationell brottsprevention av centrala brottsförebyggande aktörer i Härryda kommun?”. För att besvara frågeställningarna genomfördes en kvalitativ tematisk analys på det empiriska materialet. Undersökningens empiri består av semi-strukturerade intervjuer med två representanter för Härryda kommuns brottsförebyggande råd, samt offentliga dokument om eller med relevans för kommunens brottsförebyggande verksamhet. Resultaten visar att Härryda kommuns brottsförebyggande råd beslutat att prioritera problemområdena ”narkotika” och ”otrygghet i den fysiska miljön”. Dessa problemområden är föremål för sekundära och tertiära situationellt brottsförebyggande insatser. Det brottsförebyggande rådet samverkar i viss mån med medborgarna; platser som upplevs som otrygga prioriteras för formella och informella åtgärder. De trygghetsökande insatserna utvärderas dock inte, till skillnad från insatser riktade mot narkotikahanteringen. Härryda kommun följer de teoretiska brottspreventiva riktlinjerna, enligt rutinaktivitetsteorin och broken windows, som förordas i regeringens nationella brottsförebyggande program. Detta gäller främst att öka närvaron av kapabla väktare, bland annat genom det medborgerliga engagemanget och kameraövervakning. Det sist- nämnda är dock svårt för kommunen att implementera på grund av begränsningar i lagstiftningen. Vidare forskning om kommuners brottsförebyggande arbete förordas eftersom det råder en kunskapslucka hur kommuner implementerar de nationella brottsförebyggande programmen. Förslagsvis kan denna undersökningen fungera som underlag för jämförelsestudier med andra kommuners situationellt brottsförebyggande arbete.

Segmented regression is a type of nonlinear regression that allows differing functional forms to be fit over different ranges of the explanatory variable. This paper considers the simple segmented regression case of two linear segments that are constrained to meet, often called the linear-linear model. Parameter estimation in the case where the joinpoint between the regimes is unknown can be tricky. Using a simulation study, four estimators for the parameters of the linear-linear model are evaluated. The bias and mean squared error of the estimators are considered under differing parameter combinations and sample sizes. Parameters estimated in the model are the location of the change-point, the slope and intercept of the first segment, the change in slope from the first segment to the second, and the variance over both segments.

The broken ray transform (BRT) is an integral of a function along a union of two rays with a common vertex. Consider an X-ray beam scanning an object of interest. The ray undergoes attenuation and scatters in all directions inside the object. This phenomena may happen repeatedly until the photons either exit the object or are completely absorbed. In our work we assume the single scattering approximation when the intensity of the rays scattered more than once is negligibly small. Among all paths that the scattered rays travel inside the object we pick the one that is a union of two segments with one common scattering point. The intensity of the ray which traveled this path and exited the object can be measured by a collimated detector. The collimated detector is able to measure the intensity of X-rays from the selected direction. The logarithm of such a measurement is the broken ray transform of the attenuation coefficient plus the logarithm of the scattering coefficient at the scattering point (vertex) and a known function of the scattering angle. In this work we consider the reconstruction of X-ray attenuation coefficient distribution in a plane from the measurements on two or three collimated detector arrays. We derive an exact local reconstruction formula for three flat collimated detectors or three curved or pin-hole collimated detectors. We obtain a range condition for the case of three curved or pin-hole detectors and provide a special case of the range condition for three flat detectors. We generalize the reconstruction formula to four and more detectors and find an optimal set of parameters that minimize noise in the reconstruction. We introduce a more accurate scattering model which takes into account energy shifts due to the Compton effect, derive an exact reconstruction formula and develop an iterative reconstruction method for the energy-dependent case. To solve the problem we assume that the radiation source is monoenergetic and the dependence of the attenuation coefficient on energy is linear on an energy interval from the minimal to the maximal scattered energy. %initial radiation energy. We find the parameters of the linear dependence of the attenuation on energy as a function of a point in the reconstruction plane.

Abstrakt: Studien har genom semi-strukturerade intervjuer undersökt nyckelaktörers beskrivningar av problembilder och åtgärder i dagens Seved samt skillnader mellan beskrivningarna. Intervjudeltagarnas svar d v s resultat av uppsatsens metod har analyserats utifrån social desorganisation-teorin samt broken windows-teorin. Studiens resultat visar: att det finns stöd för flertalet av de beskrivna problembilderna/åtgärderna i dagens Seved att kopplas till social desorganisations-teorin samt dess utveckling i form av kollektiv styrka-teorin. En del av broken windows-teorins problembild kan kopplas samman till nyckelaktörers beskrivningar medan åtgärderna till största del inte överensstämmer med broken windows. Mellan nyckelaktörer finns skillnader vilka kan förklaras genom att fler nyckelaktörer i större grad grundar sina problembilder utifrån social desorganisation och färre i broken windows-teorin. Mellan vissa nyckelaktörer finns motstridiga skillnaderna vilka kan resultera i att vissa verksamheters åtgärder motverkar andra verksamheters åtgärder.