The influences of the just-in-time social cloud on real world decisions

Thesis (Ph. D.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 209-224).People have intertemporal biases towards choices that result in immediate gratification versus delayed rewards. The social context can accentuate or downplay preferences towards virtues or vices when making choices in the moment. Especially in our modern world where social networks are virtually accessible at anytime, from anywhere, how our day-today decisions are affected by the "always-on" connection to our social networks via mobile devices is an open question. By understanding the dimensions of these social forces, we can utilize the just-in-time social cloud to nudge people towards decisions that have long term benefits for health and finances, while counterbalancing the forces of the marketers that trigger our impulses towards immediate temptations that we may regret later. This work presents an empirical inquiry into the effect of just-in-time social influences in human decision-making. In order to understand these effects and discover their parameters, I design and deploy real-world experiments with the just-in-time social cloud using mobile phones as platforms for just-in-time social influence. The Open Transaction Network forms the basis of generating just-in-time social networks based on the transactions shared by people in the context of commerce. The Open Transaction Network is extended to several systems to conduct real-world experiments involving real choices. By augmenting mobile commerce applications with just-in-time social networks, I design a mobile commerce environment that can socially influence our just-in-time choices. The Open Credit Card Application Framework augments existing methods of payment by using transactions as triggers to enable mobile applications that facilitate just-in-time decisions or reflections. Friends within communities show significant similarity in their hourly transaction behaviors. Varying manifestations of the just-in-time social cloud (individual friends, groups of friends and popularity information) can be used to nudge people's choices in the dimensions of taste, price and time as they decide.by Kwan Hong Lee.Ph.D

Electromagnet Weight Reduction in a Magnetic Levitation System for Contactless Delivery Applications

This paper presents an optimum design of a lightweight vehicle levitation electromagnet, which also provides a passive guide force in a magnetic levitation system for contactless delivery applications. The split alignment of C-shaped electromagnets about C-shaped rails has a bad effect on the lateral deviation force, therefore, no-split positioning of electromagnets is better for lateral performance. This is verified by simulations and experiments. This paper presents a statistically optimized design with a high number of the design variables to reduce the weight of the electromagnet under the constraint of normal force using response surface methodology (RSM) and the kriging interpolation method. 2D and 3D magnetostatic analysis of the electromagnet are performed using ANSYS. The most effective design variables are extracted by a Pareto chart. The most desirable set is determined and the influence of each design variable on the objective function can be obtained. The generalized reduced gradient (GRG) algorithm is adopted in the kriging model. This paper’s procedure is validated by a comparison between experimental and calculation results, which shows that the predicted performance of the electromagnet designed by RSM is in good agreement with the simulation results

Nonlinear oscillations of a sessile drop on a hydrophobic surface induced by ac electrowetting

We examine the nature of ac electrowetting (EW)-driven axisymmetric oscillations of a sessile water drop on a dielectric substrate. In ac EW, small-amplitude oscillations of a drop differ from the Rayleigh linear modes of freely oscillating drops. In this paper, we demonstrate that changes in the time-averaged contact angle of the sessile drop attributed to the presence of an electric field and a solid substrate mainly caused this discrepancy. We combine the domain perturbation method with the Lindsted-Poincare method to derive an asymptotic formula for resonant frequency. Theoretical analysis shows that the resonant frequency is a function of the time-averaged contact angle. Each mode of the resonance frequency is a linear function of epsilon(1), which is the magnitude of the cosine of the time-averaged contact angle. The most dominant mode in this study, that is, the fundamental mode n = 2, decreases linearly with epsilon(1). The results of the theoretical model are compared with those of both the experiments and numerical simulations. The average resonant frequency deviation between the perturbation solutions and numerical simulations is 4.3%, whereas that between the perturbation solutions and the experiments is 1.8%.X1121sciescopu

Insulin and glucagon secretions, and morphological change of pancreatic islets in OLETF rats, a model of type 2 diabetes mellitus.

This study was performed to observe the changes of glucose-related hormones and the morphological change including ultrastructure of the pancreatic islets in the male Otsuka Long-Evans Tokushima Fatty rat. Area under the curve (AUC) of glucose at the 30th (709 plus minus 73 mg.h/dL) and at the 40th week (746 plus minus 87 mg.h/ dL) of age were significantly higher than that at the 10th week (360 plus minus 25 mg.h/ dL). AUC of insulin of the 10th week was 2.4 plus minus 0.9 ng.h/mL, increased gradually to 10.8 plus minus 8.3 ng.h/mL at the 30th week, and decreased to 1.8 plus minus 1.2 ng.h/mL at the 40th week. The size of islet was increased at 20th week of age and the distribution of peripheral alpha cells and central beta cells at the 10th and 20th weeks was changed to a mixed pattern at the 40th week. On electron microscopic examination, beta cells at the 20th week showed many immature secretory granules, increased mitochondria, and hypertrophied Golgi complex and endoplasmic reticulum. At the 40th week, beta cell contained scanty intracellular organelles and secretory granules and apoptosis of acinar cell was observed. In conclusion, as diabetes progressed, increased secretion of insulin was accompanied by increases in size of islets and number of beta-cells in male OLETF rats showing obese type 2 diabetes. However, these compensatory changes could not overcome the requirement of insulin according to the continuous hyperglycemia after development of diabetes