A spatial impedance controller for robotic manipulation

Mechanical impedance is the dynamic generalization of stiffness, and determines interactive behavior by definition. Although the argument for explicitly controlling impedance is strong, impedance control has had only a modest impact on robotic manipulator control practice. This is due in part to the fact that it is difficult to select suitable impedances given tasks. A spatial impedance controller is presented that simplifies impedance selection. Impedance is characterized using ¿spatially affine¿ families of compliance and damping, which are characterized by nonspatial and spatial parameters. Nonspatial parameters are selected independently of configuration of the object with which the robot must interact. Spatial parameters depend on object configurations, but transform in an intuitive, well-defined way. Control laws corresponding to these compliance and damping families are derived assuming a commonly used robot model. While the compliance control law was implemented in simulation and on a real robot, this paper emphasizes the underlying theor

Sliding mode control of spatial mechanical systems decoupling translation and rotation

This paper looks at the robust trajectory control of spatial mechanical systems using sliding mode techniques. Two distinctions of the proposed method from reported methods are: (1) The measure of attitudinal error used is intrinsically defined, Euclidean-geometric, and intuitive. From Euler's theorem it follows that given a desired and actual attitude of a rigid body there exists an axis and angle of rotation relating the two attitudes. This defines a relative rotation vector, which is used as an intrinsically defined, intuitive measure of error. Reported methods use algebraic differences of entities such as generalized coordinates representing attitude. While functionally correlated to attitudinal error, these measures are not intrinsically defined. (2) A novel, dynamically nonlinear sliding function is used that results in a simple control law. The parameters of this function are dynamically and geometrically intuitive. Simulation results are given for a spacecraft tracking a complex desired trajectory

A Systematic Review of Rural Veteran Homelessness

This study is a systematic review to examine homeless veterans identified to be most at risk of unsuccessfully completing the VA’s housing program (HUD-VASH), which promotes the use of Housing First (HF) as it’s model for treating homelessness. The literature review identified those who were rural and experiencing comorbid substance use disorders (SUD) and mental health issues to likely be those who were most at risk. There were multiple reasons why this subgroup was most vulnerable including limited access to resources, higher levels of substance use and more serious mental health diagnoses, and chronic health needs. Both the literature review and systematic review in this study indicate a lack of evidence supporting Housing First especially its long-term effectiveness in the HUD-VASH program. The lack of evidence is due in part to the question of whether or not the programs examined in the literature are true HF models, which utilize all the core principles of HF. Further, the literature regarding HF predominantly measures the length of time to acquire permanent housing with little to no regard to harm reduction or rehabilitation of SUD and mental health needs. Further research is also needed to examine HUD-VASH effectiveness in treating rural veterans with comorbid SUD and mental health illnesses

The importance of interaction for academic success in online courses with hearing, deaf, and hard-of-hearing students

This paper reports the findings of three studies within a program of research designed to better understand the factors contributing to the academic achievement of students in online courses and the contributions of interaction to online learning. The first study compared the academic achievement of students in the online and face-to-face (F2F) sections of multiple courses. In the second study, an online survey was used to obtain student perceptions of course satisfaction, learning, and communication. These factors were then related, using binary logistic regression analysis, to the amount of interaction that occurred in the students’ respective online courses; information from the myCourses course management system was used to quantify the amount of interaction that occurred in online courses. In the final study, both datasets were used to examine the academic achievement of students in online courses based upon the amount of interaction that had actually occurred. Whenever possible, a subgroup of deaf and hard-of-hearing students was included in the study to increase our understanding of the role that communication plays in the teaching-learning process. Our findings indicate that students enrolled in online courses, especially those designed with high levels of online interaction, receive higher grades and report greater learning than students in comparable F2F courses. In addition, online courses appear to provide deaf and hard-of-hearing students with special benefits in terms of academic achievement through online discussion. Overall, the studies illuminate how the quantity of interaction in online discussions relates to important success factors. Students in online courses with more interaction outperformed students in online courses with less interaction

Perceptions of, and attitudes towards, English teaching and learning in Cameroon’s technical education

This study examined the current practices, difficulties and impacts of English as second official language (ESOL) teaching and learning in secondary schools in Cameroon. It investigated the perceptions and attitudes of students, teachers and parents towards the teaching and learning of ESOL, including prevailing teaching and learning practices. This study stemmed from the observation that the exit profile of most students in technical secondary schools does not correspond to the official exit profile set out by the Ministry of Secondary Education (MINESEC). It was therefore necessary to survey students, parents, and teachers with the goal of identifying areas of concern and proposing remedial solutions. Responses of these key stakeholders selected in four education institutions (including two technical high schools and two general high schools) to questionnaires have provided data for the study. Such responses offered insights into the current situation in Cameroon’s ESOL, as well as into the possible utility of, and desire for, the development of ESOL courses aimed at students learning in technical schools. The inclusion and development of English for specific purposes (ESP) in Cameroon’s ESOL teaching and learning could help bring education stakeholders and policymakers closer to what they want to see from the country’s ESOL program

“It’s a silver lining”: A template analysis of satisfaction and quality of life following post-mastectomy breast reconstruction

The file attached to this record is the author's final peer reviewed version.Objective: In the United Kingdom, the number of women electing to undergo post-mastectomy breast reconstruction is increasing. As a consequence exploring patient-reported outcomes in breast surgery has become increasingly important. This study aims to explore satisfaction and quality of life following post-mastectomy breast reconstruction. Design: Qualitative research design. Methods: In-depth, semi-structured telephone interviews were conducted with 25 women, (Age, M= 53.08, SD=8.41) following breast reconstruction in the United Kingdom. Data were analysed using template analysis which produced three first-level, 13 second-level and 19 third-level themes. Results: Following reconstruction women reported improved emotional functioning, although this was often accompanied with deterioration in physical, sexual and/or social functioning. Women positively appraised their breast appearance, although some reported a decline in satisfaction over time and attributed this decline to their chosen reconstructive technique. Many women accepted the inevitability of scarring and most perceived their scars as a representation of their journey, signifying survival. Generally women were satisfied with the outcome of their reconstruction, although on reflection some would not have opted for reconstruction. Following breast reconstruction women were increasingly likely to experience the fear of recurrence, attributed to no longer being able to have a mammogram on the affected breast(s). Conclusions: This study provides new insights into post-mastectomy breast reconstruction and is a novel application of the qualitative data analysis method, template analysis. Template analysis demonstrates only slight variation in some categories of experience among women, despite a heterogeneous sample. The findings allow researchers and clinicians to focus on specific dimensions of satisfaction and quality of life to positively support the needs of women following reconstructio

Probe! – Praxislabors für kreative Lernwege. Ein Konzept für offene Lernprozesse in heterogenen Lerngruppen

Der vorliegende Artikel stellt das Format von „PROBE! – Praxislabors für kreative Lernwege“ vor, das ausgehend von Projekten im vielsprachigen Subsahara-Afrika entwickelt wurde. Beispielhaft wird eines dieser Projekte beschrieben. Erfahrene Pädagogen bilden die „PROBE!“-Teams und führen in Workshops – den Praxislabors – Theater- und Spracharbeit zusammen. In heterogenen Lerngruppen nutzen die „Probe!“-Teams die Kreativität von Kindern und Jugendlichen in künstlerischen Arbeitsprozessen. Theatrale Verfahren werden dabei verbunden mit Ansätzen aus der Mehrsprachigkeitsdidaktik, mit Körperarbeit und Kommunikationstraining. Den Teilnehmer/innen wird so die Gelegenheit gegeben, ihre sprachliche und kulturelle Identität zu erforschen, sie wechselseitig anzuerkennen und eigene sprachliche, soziale und arbeitstechnische Kompetenzen weiter auszubilden. Alle Workshops schließen mit einer Präsentation ab, die jedoch nicht das alleinige Ziel ist: vielmehr intensivieren die Teilnehmer/innen im Arbeitsprozess ihre Fähigkeit des präzisen Beobachtens, sie entwickeln eigene Notationssysteme und können so ihre Sicht auf Arbeitsverfahren und Ergebnis formulieren. Auf der Grundlage des jeweils eigenen Zugangs werden Inhalte aus Spracharbeit, Literatur und individuellen Lebensgeschichten der Teilnehmenden aus einer neuen Perspektive sichtbar und erfolgreich bearbeitet

Im Zeichen des "Tankdrachen"

Gegenstand der vorliegenden Dissertationsschrift ist das zumeist als Revolution of Military Affairs wahrgenommene Auftreten der ersten Panzer. Diese „Tanks“ der Jahre 1916-1918 mit den ihnen innewohnenden Möglichkeiten, das blutige Patt des Stellungskrieges an der Westfront aufzuheben, beeinflußten der Legende nach das Kriegsende 1918 erheblich. Die Alliierten erkannten das Potential der neuen Waffe, ließen sich von frühen Rückschlägen nicht entmutigen und besaßen gegen Ende des Krieges eine gepanzerte Speerspitze ihrer nun modern auf Feuer und Bewegung ausgelegten Offensiven, denen man deutscherseits angeblich nichts entgegenzusetzen hatte. Die deutsche Führung, anscheinend geprägt durch technikfeindliche und geradezu blauäugig agierende Köpfe, verpaßte bis zuletzt ignorant jede Chance, ihrerseits auf diese die Landkriegführung bis heute prägende Waffe zu setzen und selbst Tanks in Massen zu produzieren. Im Sommer 1918 kollabierten die deutschen Linien, als britische, französische und amerikanische Tankgeschwader unaufhaltsam auf sie und ihre technisch und taktisch plötzlich hoffnungslos unterlegenen Verteidiger einstürmten. Inwieweit diese plausibel erscheinende Darstellung den Realitäten in höchsten Führungskreisen beider Seiten und auf den Gefechtsfeldern entsprach, ist eine grundsätzliche Frage innerhalb der vorliegenden Dissertation. Anhand der operationsgeschichtlichen Untersuchung der namhaftesten Tankeinsätze zwischen dem ersten Auftreten der neuen Waffe im September 1916 und ihrem Siegeslauf im Sommer 1918 wird geklärt, welcher Anteil am alliierten Sieg den frühen Panzern zuzubilligen ist und inwiefern sich die deutsche Führung tatsächlich eines letztlich katastrophalen „Versagens“ schuldig machte.The central theme of this thesis is the appearance on the battlefield of the first armoured vehicles, an event generally held to have been a revolution in military affairs. The exploits of these so-called ‘tanks’ of 1916 -1918, which had the inherent capability of breaking the bloody deadlock of trench warfare, contributed greatly during the interwar period to the promotion of a myth, which went roughly as follows: The Allies had recognised the potential of this new weapon; did not allow themselves to be deflected by early setbacks and so, towards the end of the war, their modern offensives, founded on the joint principles of fire and manoeuvre, possessed an armoured spearhead, against which the Germans had no answer. The German High Command, seemingly technophobic and blundering, ignored right to the bitter end, the chance to throw their weight behind the development and mass production of weapons, which to this day play a key role in land warfare. In the summer of 1918 the German lines simply folded in the face of British, French and American tank squadrons which rolled forward unstoppably to assault a defence which was suddenly and hopelessly tactically and technically inferior. The fundamental question of this thesis is to what extent this apparently plausible representation of the facts actually corresponds to the reality, both in the High Commands of both sides and on the battlefield. On the basis of historical-operational analysis of the most notable tank actions between the first appearance of the new weapon in September 1916 and its advance to victory during the summer of 1918, the thesis explores how much credit for the Allied victory is due to these early armoured vehicles and to what extent the German High Command itself was actually responsible for this final, catastrophic failure

Effects of different fertilizers on methane emission from paddy field of Zhejiang, China

No Abstract

Non-traditional students: Recruitment strategies and their effectiveness

In recent years, there has been considerable change in the student population in postsecondary education. At one time, a college campus consisted primarily of students who were 18 to 22 years of age. A decline in this population has been occurring for several years and is predicted to continue. There will simply be fewer youngsters coming through grade school and high school in the 1990\u27s. They have already been born (Hruby, 1984, p.4). At the same time, the number of older, non-traditional students has been increasing on college campuses. According to Brodzinski (1980), the number of students who were at least 35 years old increased-more than 66% between 1972 and 1978. Haponski (1983)·noted that (a)dults constituted 37.5%of the total college enrollment in 1978 and are expected to constitute 47% by 1990 (p. 1)