A linearly controlled direct-current power source for high-current inductive loads in a magnetic suspension wind tunnel

The NASA Langley 6 inch magnetic suspension and balance system (MSBS) requires an independently controlled bidirectional DC power source for each of six positioning electromagnets. These electromagnets provide five-degree-of-freedom control over a suspended aerodynamic test model. Existing power equipment, which employs resistance coupled thyratron controlled rectifiers as well as AC to DC motor generator converters, is obsolete, inefficient, and unreliable. A replacement six phase bidirectional controlled bridge rectifier is proposed, which employs power MOSFET switches sequenced by hybrid analog/digital circuits. Full load efficiency is 80 percent compared to 25 percent for the resistance coupled thyratron system. Current feedback provides high control linearity, adjustable current limiting, and current overload protection. A quenching circuit suppresses inductive voltage impulses. It is shown that 20 kHz interference from positioning magnet power into MSBS electromagnetic model position sensors results predominantly from capacitively coupled electric fields. Hence, proper shielding and grounding techniques are necessary. Inductively coupled magnetic interference is negligible

Transformational Focus in Strategic IT Vision: An Industry-Level Conceptual Model

It has recently been argued that the IT literature has neglected to sufficiently focus on the importance of the influence that industry factors have on a firm’s IT strategy and IT management practices, in short – industry matters. (Chiasson & Davidson, 2005) Strategic IT Vision (SIV) has been studied at the firm level for many years. The categories Automate, Informate & Transform have been used to categorize the Strategic IT Vision of firms for more than 20 years. At the same time, some have suggested that SIV can be observed at the industry level in that, at a given time, the firms within an industry exhibit a certain amount of homogeneity of IT strategy and vision. What industry factors might lead to the adoption of a particular SIV by its firms? This paper develops a conceptual framework of industry factors that can be theorized to lead to a greater transformative nature of the SIV of a particular industry

Comparative Metabolism of Several Calcareous Minerals in Poultry Feeding

In part one of this study it was found that chickens when given oyster shells, in addition to their regular diet, produced a greater number of eggs and eggs of greater shell strength than did the chickens that were given the other calcareous materials used in this experiment. Oyster shell was followed in the order of their effectiveness by clam shells, Black Hills limestone, Nenno chalk stone, and Wisconsin dolomitie limestone

The Effect of Turnover Intention on Tie Formation in Online Organization Networks

Turnover is costly for organizations. While existing research identifies the antecedents and effects of turnover, little research exists on how to identify individuals intending to leave an organization. We hypothesize that individuals with high turnover intention will participate in fewer communication relationships than average, and that individuals prefer communicating with others of similar levels of turnover intention. We use exponential random graph modeling (ERGM) to test our hypotheses on the email and advice networks of a technology company. ERGM allows us to simultaneously examine the effect of individual and dyadic level attributes on network formation. The results support our hypotheses in the email network, but not in the advice network. Our findings imply that organizations should examine their email networks to identify individuals with high turnover intention, and intervene with incentives if they wish to retain the employees

Partners in Prevention: Community-Wide Homelessness Prevention in Massachusetts and the United States

Examines six community initiatives to prevent homelessness involving cross-organizational resource-sharing, policies, and interventions. Looks at each program's strategy, organization, interventions, and approaches to partnerships, outcomes, and funding

The Social Structure of the Information Systems Collaboration Network: Centers of Influence and Antecedents of Tie Formation

In this study, we examine the historical information systems research collaboration network. We build the network using coauthorship information in the Senior Scholars’ basket of eight journals from the publication of MISQ’s first issue in April, 1977, to November, 2015. The different journals vary widely in their network configurations. We examine the influence of gender homophily, geographic homophily, and field tenure heterophily on coauthorship in the network. From using exponential random graph modeling (ERGM) on a randomly selected subset of the network, we present preliminary evidence that suggests that ties in the IS collaboration network exhibit homophily according to gender and geography. Conversely, coauthorship seems to exhibit heterophily along the temporal dimension: short-tenured researchers in the field prefer to collaborate with long-tenured researchers. ERGM enables one to make statistical inferences concerning the influence of node attributes and structural variables on network formation, which is hard to do with logistical regression because network relationships violate the independence of observations assumption. We also reveal the current center of the IS collaboration network. Based on this center, we propose a metric to measure a researcher’s connectedness in the network

Introduction to Agile and Lean Discovery and Development Minitrack

N/

A Quantitative and Qualitative Study of Facebook Privacy using the Antecedent-Privacy Concern-Outcome Macro Model

Information privacy is a complex and important phenomenon to understand. Because of this, several recent review articles have integrated findings across various studies and contexts. In this study we investigate information privacy in the online social networking context using the Antecedent-Privacy Concern-Outcome (APCO) Macro Model as the theoretical lens. We use both quantitative and qualitative data collected in a survey of Facebook users. Online social networking provides a rich window into privacy concerns and the resulting behavioral reactions. By analyzing both types of data, we are able to show additional support and insights for our hypotheses tests. These results provide future research opportunities that include modifying the APCO model and refining its constructs to be more context and risk-specific