Mobility modeling and management for next generation wireless networks

Mobility modeling and management in wireless networks are the set of tasks performed in order to model motion patterns, predict trajectories, get information on mobiles\u27 whereabouts and to make use of this information in handoff, routing, location management, resource allocation and other functions. In the literature, the speed of mobile is often and misleadingly referred to as the level of mobility, such as high or low mobility. This dissertation presents an information theoretic approach to mobility modeling and management, in which mobility is considered as a measure of uncertainty in mobile\u27s trajectory, that is, the mobility is low if the trajectory of a mobile is highly predictable even if the mobile is moving with high speed. On the other hand, the mobility is high if the trajectory of the mobile is highly erratic. Based on this mobility modeling concept, we classify mobiles into predictable and non-predictable mobility classes and optimize network operations for each mobility class. The dynamic mobility classification technique is applied to various mobility related issues of the next generation wireless networks such as location management, location-based services, and energy efficient routing in multihop cellular networks

Cost Optimization Modeling for Airport Capacity Expansion Problems in Metropolitan Areas

The purpose of this research was to develop a cost optimization model to identify an optimal solution to expand airport capacity in metropolitan areas in consideration of demand uncertainties. The study first analyzed four airport capacity expansion cases from different regions of the world to identify possible solutions to expand airport capacity and key cost functions which are highly related to airport capacity problems. Using mixedinteger nonlinear programming (MINLP), a deterministic optimization model was developed with the inclusion of six cost functions: capital cost, operation cost, delay cost, noise cost, operation readiness, and airport transfer (ORAT) cost, and passenger access cost. These six cost functions can be used to consider a possible trade-off between airport capacity and congestion and address multiple stakeholders’ cost concerns. This deterministic model was validated using an example case of the Sydney metropolitan area in Australia, which presented an optimal solution of a dual airport system along with scalable outcomes for a 50-year timeline. The study also tested alternative input values to the discount rate, operation cost, and passenger access costs to review the reliability of the deterministic model. Six additional experimental models were tested, and all models successfully yielded optimal solutions. The moderating effects of financial discount rate, airport operation cost, and passenger access costs on the optimal solution were quantitatively the same in presence of a deterministic demand profile. This deterministic model was then transformed into a stochastic optimization model to address concerns with the uncertainty of future traffic demand, which was further reviewed with three what-if demand scenarios of the Sydney Model: random and positive growth of traffic demand, normal distribution of traffic demand changes based on the historical traffic record of the Sydney region, and reflection of the current COVID- 19 pandemic situation. This study used a Monte Carlo simulation to address the uncertainty of future traffic demand as an uncontrollable input. The Sydney Model and three What-if Models successfully presented objective model outcomes and identified the optimal solutions to expand airport capacity while minimizing overall costs. The results of this work indicated that the moderating effect of traffic uncertainties can make a difference with an optimal solution. Therefore, airport decision-makers and airport planners should carefully consider the uncertainty factors that would influence the airport capacity expansion solution. This research demonstrated the effectiveness of combining MINLP and the Monte Carlo simulation to support a long-term strategic decision for airport capacity problems in metropolitan areas at the early stages of the planning process while addressing future traffic demand uncertainty. Other uncertainty factors, such as political events, new technologies, alternative modes of transport, financial crisis, technological innovation, and demographic changes might also be treated as uncontrollable variables to augment this optimization model

Observation of Topologically Stable 2D Skyrmions in an Antiferromagnetic Spinor Bose-Einstein Condensate

We present the creation and time evolution of two-dimensional Skyrmion excitations in an antiferromagnetic spinor Bose-Einstein condensate. Using a spin rotation method, the Skyrmion spin textures were imprinted on a sodium condensate in a polar phase, where the two-dimensional Skyrmion is topologically protected. The Skyrmion was observed to be stable on a short time scale of a few tens of ms but to have dynamical instability to deform its shape and eventually decay to a uniform spin texture. The deformed spin textures reveal that the decay dynamics involves breaking the polar phase inside the condensate without having topological charge density flow through the boundary of the finite-sized sample. We discuss the possible formation of half-quantum vortices in the deformation process.Comment: 5 pages, 5 figure

Preclinical Efficacy Examination on Healing Practices and Experiences of Users for Pillows and Mattresses of Loess Ball Bio-products

AbstractIn Korea, loess has been known as a healthy material traditionally, and in everyday life it has been used in various fields. Korean loess ball has unique electrical and magnetic properties indispensable to survival of human being such as living-light of far-infrared radiation which has been applied to various bio-products. However, the medical investigation of its efficacy for such bio-products has remained insufficient. The purpose of this paper is to check not only chemico-physical data but also medical data on the medical efficacy for the various healing practices and effects shown in users of these products. The Korean loess ball was manufactured by several powder processes at low temperature such as aging, mild grinding, separation, granulation, and drying. The healing effects for the bio-products of the loess ball were confirmed based on the statistical analysis of user's experience for healing practices evaluated by Somatoscope microscope observations of the movement of red blood cells in living blood, the infrared thermography diagnostic equipment, the comparison of Digital Infrared Thermal Imaging, DITI photos, the survey of literature review on the loess healing including the Donguibogam edited by Jun Heo. In conclusion, when slept on loess ball bio-products such as pillows or mattresses, the congestion of red cells in the blood of the human body is relieved and the blood circulation in blood vessel is smoothly improved. The wave resonance actions of far-infrared rays radiated from the loess ball bio-products enforce the receptor and intracellular enzymes to act the interaction of a variety of pain and stress and to bring a healthy condition. Further study for clarifying medical healing mechanisms of bio-products through the clinical test in both the oriental and western hospital is requested and the upgrade of present bio-products becomes obvious

Who Are These Sneakerheads?

Despite an increasing social significance within the sneakerhead culture (i.e., consumption misbehaviors), an understanding of sneakerheads in terms of their perceptions, motivations and decision-making processes is virtually non-existent. In order to fill a gap in the literature, the current study incorporates a Grounded Theory (Glaser & Strauss, 2009) approach and aims to address 3 research questions; 1) Why do these sneakerheads buy, collect, and wear sneakers with such a high level of enthusiasm?, 2) How do these sneakerheads go about buying, collecting, and wearing sneakers?, and 3) What perceptions do these sneakerheads have regarding inequity and violent incidents related to the limited release of highly anticipated sneakers

The Double-edge Sword of Limited Edition Fashion Marketing

The primary purpose of this study was to investigate the underlying psychological process by which limited edition marketing of fashion goods impacts consumers\u27 attitudes and behavioral intentions. An online experiment was conducted using Amazon Mechanical Turk. Fictitious scenarios reflecting two different levels of perceived competition (high and low) were carefully developed from pretest. Also, two different fashion products (sneakers and fast-fashion brand jackets designed by high-fashion designers) that are known to use limited-edition strategy frequently were used in the scenario. To test the hypotheses, t-test, simple regression and hierarchical regression analyses were conducted. While the perceived competition increased the perceived popularity (β=.710, p\u3c.05), the perceived competition had no influence on the perceived inequity (β=.103, p=.25). As predicted, the perceived popularity positively influenced the attitude (β=.469, p\u3c.05), while the perceived inequity negatively influenced the attitude (β=.-439, p\u3c.05). The attitude positively influenced the behavioral intentions (β=.706, p\u3c.05)

Relaxation of superfluid turbulence in highly oblate Bose-Einstein condensates

We investigate thermal relaxation of superfluid turbulence in a highly oblate Bose-Einstein condensate. We generate turbulent flow in the condensate by sweeping the center region of the condensate with a repulsive optical potential. The turbulent condensate shows a spatially disordered distribution of quantized vortices and the vortex number of the condensate exhibits nonexponential decay behavior which we attribute to the vortex pair annihilation. The vortex-antivortex collisions in the condensate are identified with crescent-shaped, coalesced vortex cores. We observe that the nonexponential decay of the vortex number is quantitatively well described by a rate equation consisting of one-body and two-body decay terms. In our measurement, we find that the local two-body decay rate is closely proportional to $T^2/\mu$, where $T$ is the temperature and $\mu$ is the chemical potential.Comment: 7 pages, 9 figure

Observation of a Geometric Hall Effect in a Spinor Bose-Einstein Condensate with a Skyrmion Spin Texture

For a spin-carrying particle moving in a spatially varying magnetic field, effective electromagnetic forces can arise due to the geometric phase associated with adiabatic spin rotation of the particle. We report the observation of a geometric Hall effect in a spinor Bose-Einstein condensate with a skyrmion spin texture. Under translational oscillations of the spin texture, the condensate resonantly develops a circular motion in a harmonic trap, demonstrating the existence of an effective Lorentz force. When the condensate circulates, quantized vortices are nucleated in the boundary region of the condensate and the vortex number increases over 100 without significant heating. We attribute the vortex nucleation to the shearing effect of the effective Lorentz force from the inhomogeneous effective magnetic field.Comment: 9 pages, 11 figure