MIT Space Engineering Research Center

The Space Engineering Research Center (SERC) at MIT, started in Jul. 1988, has completed two years of research. The Center is approaching the operational phase of its first testbed, is midway through the construction of a second testbed, and is in the design phase of a third. We presently have seven participating faculty, four participating staff members, ten graduate students, and numerous undergraduates. This report reviews the testbed programs, individual graduate research, other SERC activities not funded by the Center, interaction with non-MIT organizations, and SERC milestones. Published papers made possible by SERC funding are included at the end of the report

The Self Organised Learning Environment (SOLE) School Support Pack.

This document is designed to support the implementation of Sugata Mitra’s Self Organised Learning Environment (SOLE) into multiple school contexts. It contains ‘whole school’ related information for Head Teachers and senior staff in addition to teaching and learning support for teachers and support staff. A kindle version of Sugata Mitra's "Beyond the Hole in the Wall: Discover the Power of Self-Organized Learning" is available here http://goo.gl/iaL4B

Male mice emit distinct ultrasonic vocalizations when the female leaves the social interaction arena.

Adult male mice emit large number of complex ultrasonic vocalizations (USVs) when interacting with adult females. Call numbers and call categories differ greatly among inbred mouse strains. Little is known about USV emissions when the social partner departs. To investigate whether call repertoires and call rates are different when the male is interacting with a female and after the removal of the female, we designed a novel male-female social interaction test in which vocalizations were recorded across three phases. During phase 1, the male subject freely interacts with an unfamiliar estrus female mouse in a clean cage for 5 min. During phase 2, the female is removed while the male remains in the cage for 3 min. During phase 3, the same female is returned to the cage to rejoin the male subject mouse for 3 min. C57BL/6J (B6), FVB.129P2-Pde6b(+) Tyr(c-ch)/Ant (FVB), and BTBR T+ tf/J (BTBR) male subject mice were tested in this paradigm. All three strains emitted USVs during their initial interaction with the female partner. When the female was reintroduced in phase 3, numbers of USVs were similar to the initial introductory phase 1. Strain comparisons indicated fewer calls in pairs of BTBR males and stimulus females than in pairs of B6 males and stimulus females and pairs of FVB males and stimulus females. In the absence of the female, all FVB males vocalized, while only one third of B6 males and one third of BTBR males vocalized. In all three strains, changes in call category repertoires were detected after the female was removed. Call categories reverted to the phase 1 pattern when the female was returned in phase 3. Present findings indicate that males of commonly used inbred strains emit USVs when a partner female leaves the testing arena, suggesting that removing a salient social stimulus may be a unique approach to elicit USVs from mice. Our three-phase paradigm may also be useful for studying attention to social cues, and qualitative differences in vocalizations when a social partner is present vs. suddenly absent

Middeck Active Control Experiment (MACE), phase A

A rationale to determine which structural experiments are sufficient to verify the design of structures employing Controlled Structures Technology was derived. A survey of proposed NASA missions was undertaken to identify candidate test articles for use in the Middeck Active Control Experiment (MACE). The survey revealed that potential test articles could be classified into one of three roles: development, demonstration, and qualification, depending on the maturity of the technology and the mission the structure must fulfill. A set of criteria was derived that allowed determination of which role a potential test article must fulfill. A review of the capabilities and limitations of the STS middeck was conducted. A reference design for the MACE test article was presented. Computing requirements for running typical closed-loop controllers was determined, and various computer configurations were studied. The various components required to manufacture the structure were identified. A management plan was established for the remainder of the program experiment development, flight and ground systems development, and integration to the carrier. Procedures for configuration control, fiscal control, and safety, reliabilty, and quality assurance were developed

Stories of Resistance to Religious Authority: A Discursive Analysis

Abuses of power within certain religious communities have become a matter of public concern in recent decades. Less well known are the stories of people within local Christian communities who experience practices of religious authority which do not make headlines, but which nonetheless diminish the possibilities of their lives. Feminist analyses have highlighted the historical, cultural, and theological roots of the oppression of women in Christian communities, but work remains to be done on understanding how other subjugating practices, which oppress women and men, and resistance to such practices, are produced in religious contexts. This study asks (1) how it is that regimes of power and knowledge can subvert the call to freedom and justice which is pervasive in longstanding streams of Christian tradition, and (2) what has enabled some people to resist the practices of religious authority constructed by such regimes. In responding to these questions this thesis adopts a poststructuralist conceptual framework, drawing particularly on Foucault’s theorisation of knowledge, power, and subjectivity. In addition to Foucauldian ideas, poststructuralist feminist discussions of human agency, and Sampson’s (1993) notion of monologic and dialogic power relations, strongly influence the theoretical and ethical stance of this study. Semi-structured interviews were conducted with nine people, from a variety of Christian communities within New Zealand, who at some time had found it necessary to resist everyday practices of religious authority within their contexts. The interviews focused on their accounts of the subjugating practices they had encountered, the effects of those practices on their lives, and their acts of resistance. A discursive approach to narrative analysis was developed and applied to transcriptions of these interviews. This analysis identified a range of discursive technologies which had contributed to the subjugation of the participants and protected the hegemony of discourses which supported subjugating practices. This study concludes that (1) monologic power relations within religious communities are a primary indicator of problematic discourses and practices of authority; (2) the “Man of God” discourse and its variants inevitably subvert freedom and justice; (3) sexual abuse by religious leaders belongs to a spectrum of discursively produced entitlement practices; (4) the embodied effects of subjugation bear witness to ethical hopes and intentions, and are instrumental in producing resistance; and (5) repeated exposure to a range of religious texts and rituals both supports and subverts people’s subjectification within the dominant discourses of a religious community

Report: Seminar on Governance and Media Reform in Sri Lanka and the Commonwealth

The trigger for this seminar had been the publication earlier in the year of the book ‘Embattled Media: Democracy, Governance and Reform in Sri Lanka’. One of the main aims of the book was to analyse issues of media practice and regulation - both abuses and the potential reform of those abuses – in the specific circumstances of Sri Lanka. The seminar had a broader aim to explore and compare thinking and practice affecting media and journalism in countries with other legal and constitutional foundations and cultural inheritances. We aim to go beyond the parameters of the book and hear from speakers with wide experience of the dilemmas facing policy makers in high income, middle income and low income countries. The three distinguished speakers in the seminar’s second session will reflect on best practice in Commonwealth countries regarding the promotion of media development and the safeguarding of media freedoms

Quantized multiplicative quiver varieties

Beginning with the data of a quiver Q, and its dimension vector d, we construct an algebra D_q=D_q(Mat_d(Q)), which is a flat q-deformation of the algebra of differential operators on the affine space Mat_d(Q). The algebra D_q is equivariant for an action by a product of quantum general linear groups, acting by conjugation at each vertex. We construct a quantum moment map for this action, and subsequently define the Hamiltonian reduction A^lambda_d(Q) of D_q with moment parameter \lambda. We show that A^\lambda_d(Q) is a flat formal deformation of Lusztig's quiver varieties, and their multiplicative counterparts, for all dimension vectors satisfying a flatness condition of Crawley-Boevey: indeed the product on A^\lambda_d(Q) yields a Fedosov quantization the of symplectic structure on multiplicative quiver varieties. As an application, we give a description of the category of representations of the spherical double affine Hecke algebra of type A_{n-1}, and its generalization constructed by Etingof, Oblomkov, and Rains, in terms of a quotient of the category of equivariant D_q-modules by a Serre sub-category of aspherical modules.Comment: Re-written introduction, improvements to expositio

The Middeck Active Control Experiment (MACE)

The Middeck Active Control Experiment (MACE) is a NASA In-Step and Control Structure Interaction (CSI) Office funded Shuttle middeck experiment. The objective is to investigate the extent to which closed-loop behavior of flexible spacecraft in zero-gravity (0-g) can be predicted. This prediction becomes particularly difficult when dynamic behavior during ground testing exhibits extensive suspension and direct gravity coupling. On-orbit system identification and control reconfiguration is investigated to improve performance which would otherwise be limited due to errors in prediction. The program is presently in its preliminary design phase with launch expected in the summer of 1994. The MACE test article consists of three attitude control torque wheels, a two axis gimballing payload, inertial sensors and a flexible support structure. With the acquisition of a second payload, this will represent a multiple payload platform with significant structural flexibility. This paper presents on-going work in the areas of modelling and control of the MACE test article in the zero and one-gravity environments. Finite element models, which include suspension and gravity effects, and measurement models, derived from experimental data, are used as the basis for Linear Quadratic Gaussian controller designs. Finite element based controllers are analytically used to study the differences in closed-loop performance as the test article transitions between the 0-g and 1-g environments. Measurement based controllers are experimentally applied to the MACE test article in the 1-g environment and achieve over an order of magnitude improvement in payload pointing accuracy when disturbed by a broadband torque disturbance. The various aspects of the flight portion of the experiment are also discussed

MIT Space Engineering Research Center testbed programs

The Space Engineering Research Center (SERC) at M.I.T., started in July 1988, has completed two and one-half years of research. This Semi-Annual Report presents annotated viewgraph material presented at the January 1991 Steering Committee and Technical Representative Review. The objective of the Space Engineering Research Center is to develop and disseminate a unified technology of controlled structures. There has been continued evolution of the concept of intelligent structures (including in this past year the first successful embedding of a microelectronic component into a structural element)