Design and Analysis of Electrical Power and Communication Systems for 3U SeaLion CubeSat Mission

Old Dominion University (ODU) Space Systems students in conjunction with the United States Coast Guard Academy (USCGA) are designing and developing a 3U Very Low Earth Orbit (VLEO) CubeSat mission aptly named SeaLion. This work specifically details the design of the Electrical Power System (EPS) and Communication System of the satellite. Electrical power in orbit is a precious commodity and must be carefully regulated and distributed to ensure the satellite’s operational health. Commonly, CubeSat electrical power is retained in orbit via outward facing solar cells and stored in onboard rechargeable batteries. This thesis proposes using non-rechargeable primary battery cells and custom hardware to maximize operational time with strict Very Low orbital lifetime constraints. Primary battery cell choice and the encompassing battery power supply design with reliability features are provided. Major functions of the EPS including voltage and current regulation and circuit protection and monitoring are also designed and analyzed for performance and reliability. The communication system consists of two half-duplex radios centered in the UHF and S-Band frequency bands to communicate with the Virginia CubeSat Constellation (VCC) and Mobile CubeSat Command and Communications (MC3) ground station networks, respectively. The design and analysis provided show the viability and cost efficiency of using primary cells and custom and readily available hardware for Very Low Earth Orbit CubeSat missions

A Follow-up Study of Technology Education Graduates of Old Dominion University 1986-1996

Through the follow-up study, data was collected toward fulfilling the following objectives: 1) to determine if graduates of Old Dominion University\u27s Technology Education Undergraduate Program were adequately prepared to assume teaching positions; 2) to determine whether the goals established in the college\u27s conceptual framework were being attained; 3) to determine if these graduates are teaching traditional vocational programs or technology education; 4) to determine what improvements can be made to the undergraduate curriculum at Old Dominion University based upon graduate\u27s feedback

On the subalgebra lattice of a Leibniz algebra

In this paper, we begin to study the subalgebra lattice of a Leibniz algebra. In particular, we deal with Leibniz algebras whose subalgebra lattice is modular, upper semi-modular, lower semi-modular, distributive, or dually atomistic. The fact that a non-Lie Leibniz algebra has fewer one-dimensional subalgebras in general results in a number of lattice conditions being weaker than in the Lie case

NETWORKS AND PERFORMANCE IN PUBLIC ORGANIZATIONS: THEORY, MODELS, AND MEASUREMENT

This study explores the antecedents of intra-organizational networks and the consequences of network structure on the attitudes and performance of public school teachers in twenty-one schools. On the antecedent side, the relationships among teacher social networks, teacher attributes, and interpersonal perceptions were assessed. The results, based on a meta-analysis of each school's statistical model, indicate that teacher interpersonal perceptions along eleven salient personality traits were important predictors of network formation. The results point toward the significance of psychological and cognitive factors in network formation that are often overlooked in structural analysis. Network autocorrelation models were used to assess how the attitudes and beliefs of a teacher's peers in the advice and friendship networks influence the teacher's own attitudes and beliefs. While the total quantity of network activity was shown to have little effect on measures of self-efficacy and organizational commitment, the quality of one's social connections was strongly predictive. For student engagement efficacy, classroom management efficacy, instructional strategy efficacy, and organizational commitment, teachers were positively influenced by the efficacy and commitment beliefs of their peers in the advice network. Therefore, it was not simply the number of connections a teacher formed in a network that was important but rather the attitudes and beliefs held by those social connections. Analysis revealed that friendship ties, which are capable of transmitting negative dialogue and sentiment, can potentially have a detrimental influence on efficacy and commitment when those ties do not coexist with advice ties. Value-added measures of teacher performance were built to measure the gain in student test scores that could be attributed to a particular teacher. Statistical models showed that two variables were significant and positive predictors of both math and reading value-added: the amount of reflective dialogue in the school and the organizational commitment of a teacher's peers. The latter variable suggests that teacher performance is driven by social connections to strongly committed coworkers rather than one's own sense of organizational commitment. Overall, the study provides strong evidence of the importance of social connections within schools and suggests that current policy aimed at creating greater levels of competition among teachers in schools may be counterproductive as competition can hinder collaboration

Structural distinctions of Fe2O3-In2O3 composites obtained by various sol-gel procedures, and their gas-sensing features

New and various approaches to the sol–gel synthesis of advanced gas-sensing materials based on nanosized Fe2O3–In2O3 (9:1 mol) mixed oxides, which differ in phase composition and grain size, have been considered in this paper. The correlation between the structural features of the composites and their gas-sensing behavior has been established. It was found that multi-phase Fe2O3–In2O3 composites containing metastable -Fe2O3 structure are characterized by the greatest sensitivity to both reducing (C2H5OH) and oxidizing (NO2) gases tested in this paper. The influence of synthesis conditions on the structural peculiarities of the Fe2O3–In2O3 composites was studied in detail and the possibility to adjust fine structure of the materials was demonstrated

A General Framework for Hierarchical Redundancy Resolution Under Arbitrary Constraints

The increasing interest in autonomous robots with a high number of degrees of freedom for industrial applications and service robotics demands control algorithms to handle multiple tasks as well as hard constraints efficiently. This paper presents a general framework in which both kinematic (velocity- or acceleration-based) and dynamic (torque-based) control of redundant robots are handled in a unified fashion. The framework allows for the specification of redundancy resolution problems featuring a hierarchy of arbitrary (equality and inequality) constraints, arbitrary weighting of the control effort in the cost function and an additional input used to optimize possibly remaining redundancy. To solve such problems, a generalization of the Saturation in the Null Space (SNS) algorithm is introduced, which extends the original method according to the features required by our general control framework. Variants of the developed algorithm are presented, which ensure both efficient computation and optimality of the solution. Experiments on a KUKA LBRiiwa robotic arm, as well as simulations with a highly redundant mobile manipulator are reported.Comment: 19 pages, 19 figures, submitted to the IEE