By Joon Ahn, Maheswaran Sathiamoorthy, Bhaskar Krishnamachari, Fan Bai, Lin Zhang
IEEE Transactions on Mobile Computing
2014
Disseminating shared information to many vehicles could
incur significant access fees if it relies only on unicast cellular communications. We consider the problem of efficient content dissemination over a vehicular network, in which vehicles are equipped with two kinds of radios: a high-cost low-bandwidth, long-range cellular radio, and a free high-bandwidth short-range radio. We formulate and solve an optimization problem to maximize content dissemination from the infrastructure to vehicles within a predetermined deadline while minimizing the cost associated with communicating over the cellular connection. We examine numerically the tradeoffs between cost, delay and system utility in the optimum regime. We find that, in the optimum regime,
(a) system utility is more sensitive to the cost budget when the allowed
delay for the dissemination is not large, (b) the system requires relatively
smaller cost budget as more vehicles participate and more delay is
allowed, (c) when the cost is very important, it is better not to spread
the content if it needs small delay. We also develop a polynomial-time
algorithm to obtain the optimal discrete solution needed in practice.
Finally, we verify our analysis using real GPS traces of 632 taxis in
Beijing, China.
By Azad M. Madni
IEEE Systems, Man and Cybernetics Magazine
2019
We are living in an era driven by exponentials and defined by hyperconnectivity, growing complexity, and increasing convergence among disciplines. In response to these trends, and at the urging of the research community, systems engineering (SE) is undergoing a timely transformation that includes developing formal underpinnings and reaching out to other disciplines to make connections and identify synergies. The impetus for this transformation stems, in part, from the National Academy of Engineering (NAE) Grand Challenges, which are mostly complex systems problems requiring contributions from multiple disciplines. Against this backdrop, this article defines various convergence types and the integrative discipline of transdisciplinary SE (TSE). TSE, enabled, in large part, by the growing convergence of engineering with other disciplines, has the potential to achieve unprecedented advances in both the thinking and the methods needed to address complex sociotechnical system problems. Using an NAE Grand Challenge problem as an example, this article illustrates the relevance of TSE and the opportunities available to the IEEE Systems, Man, and Cybernetics Society (SMCS) to contribute to this important area through collaboration between its technical committees and working groups from sister societies, such as the International Council on Systems Engineering (INCOSE).
By Shao-Hua Wu, Michelle L. Povinelli
We use a coupled thermal-optical approach to model the operating temperature rise in GaAs nanowire solar cells. We find that despite more highly concentrated light absorption and lower thermal conductivity, the overall temperature rise in a nanowire structure is no higher than in a planar structure. Moreover, coating the nanowires with a transparent polymer can increase the radiative cooling power by 2.2 times, lowering the operating temperature by nearly 7 K.
By Shon R. Hiatt, Jake B. Grandy, Brandon H. Lee
The Institute for Operations Research and the Management Sciences
2015
We explore how activists’ public and private politics elicit different organizational responses. Using data on U.S. petroleum companies from 1982 to 2010, we investigate how climate change activists serving as witnesses at congressional hearings and engaging in firm protests influenced firms’ internal and external responses. We find that public politics induced internally focused practice adoption, whereas private politics induced externally focused framing activities.We also find that private and public politics had an interaction effect: as firms faced more private political pressure, they were less likely to respond to public political pressures; similarly, as firms faced greater public political pressure, they were less likely to respond to private political pressures. The results suggest that activists can have a significant impact on firm behavior depending on the mix of private and public political tactics they engage in. We discuss the implications of our study for social movement research, organization theory, and nonmarket strategy.
