Accidental Peccei-Quinn Symmetry from Discrete Flavour Symmetry and Pati-Salam

We show how an accidental $U(1)$ Peccei-Quinn (PQ) symmetry can arise from a discrete $A_4$ family symmetry combined with a discrete flavour symmetry $\mathbb{Z}_3 \times \mathbb{Z}_5^2$, in a realistic Pati-Salam unified theory of flavour. Imposing only these discrete flavour symmetries, the axion solution to the strong $CP$ problem is protected from PQ-breaking operators to the required degree. A QCD axion arises from a linear combination of $A_4$ triplet flavons, which are also responsible for fermion flavour structures due to their vacuum alignments. We find that the requirement of an accidental PQ symmetry arising from a discrete flavour symmetry constrains the form of the Yukawa matrices, providing a link between flavour and the strong $CP$ problem. Our model predicts specific flavour-violating couplings of the flavourful axion and thus puts a strong limit on the axion scale from kaon decays.Comment: 14 pages, 2 figure

An Electric Assisted Turbo with Centrifugal Clutch and Axial Flux Motor

A traditional electric turbocharger (E-turbo) uses a radial flux motor coupled to the turbocharger to provide additional power to the drive the compressor at low speeds. This configuration is not compact and lacks satisfying transient response when motor is powered off because of high inertia of the wheel rotor system. This article proposes a novel E-turbo configuration that uses an axial flux motor and a centrifugal clutch so that the E-turbo is more compact with more flexible connection between motor and wheel rotor system

EXPLODED SHARING TO FACILITATE ANNOTATION

When individuals are collaborating in an online meeting, it is quite common for the presenter to share their application or desktop so that all of the meeting participants may collectively annotate on the presenter\u27s share. However, sometimes such a collective annotation may be difficult. To address such difficulties, techniques are presented herein that support an innovative method for facilitating online meeting annotation. Aspects of the presented techniques support exploding a meeting presenter\u27s share into editable elements. By applying aspects of the presented techniques, a share is no longer a bulk of a single static image but a collection of fine-grained editable elements. Through such editable elements a sharing-based annotation is easier to manipulate and more user-friendly than ever before

EXTENDED SCREENS FOR AN ONLINE MEETING BY GROUPING NEIGHBORS

An online meeting typically includes some number of participants or users. Techniques are presented herein that significantly enhance the user experience of users who join an online meeting from the same physical location and sit next to each other. Aspects of the presented techniques take the best advantage of neighboring screens in an extended screen manner, which can significantly improve user experience. For example, all of the duplicated local and remote video grids may be removed and all of the remote video grids may be shown in as large a fashion as possible. Broadly, aspects of the techniques presented herein include three steps – a local group initiator finding their neighbors, selecting some of the found neighbors for grouping, and setting the layout for the selected neighbors

Resilient Data Collection in Smart Grid

Sensors and measurement devices are widely deployed in Smart Grid (SG) to monitor the health of the system. However, these devices are subject to damage and attack so that they cannot deliver sensing data to the control center. In tree-based data collection schemes, a relay failure can further lead to unresponsiveness of all the devices in its sub-tree. In this paper, we study the resiliency issue in collecting data from SG measurement devices. We first design a protocol that guarantees successful data collection from all non-faulty devices in a backup-enabled tree structure. Then, we formulate the tree construction problem to optimize data collection time. Since the formulated problem is NP-hard, we propose a heuristic algorithm to solve it. We evaluate our algorithm using a real utility network topology. The experiment results show that our algorithm performs well in large scale networks.CREDCOpe

Secure Data Collection in Constrained Tree-Based Smart Grid Environments

To facilitate more efficient control, massive amounts of sensors or measurement devices will be deployed in the Smart Grid. Data collection then becomes non-trivial. In this paper, we study the scenario where a data collector is responsible for collecting data from multiple measurement devices, but only some of them can communicate with the data collector directly. Others have to rely on other devices to relay the data. We first develop a communication protocol so that the data reported by each device is protected again honest-but-curious data collector and devices. To reduce the time to collect data from all devices within a certain security level, we formulate our approach as an integer linear programming problem. As the problem is NP-hard, obtaining the optimal solution in a large network is not very feasible. We thus develop an approximation algorithm to solve the problem. We test the performance of our algorithm using real topologies. The results show that our algorithm successfully identifies good solutions within reasonable amount of time.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111643/1/Uludag_IEEE_SGC_14.pd

Water Vapor Independent Satellite Propulsion System (WISP) for Nanosatellite Orbit Maintenance

While nanosatellites have been widely implemented for scientific applications, power constraints, large free-space path losses, and system complexity prevent many researchers from fielding novel sensing hardware. Additionally, dead-on-arrival missions contribute to the growing volume of orbital debris. Access to lower orbits would decrease downlink losses, improve optical sensor performance, and ensure natural de-orbit for inoperable payloads. Conventional satellite propulsion technologies are capable of providing thrust required to maintain a low orbit, but increase system complexity and draw power away from the sensors. The United States Naval Academy has developed the Water Vapor Independent Satellite Propulsion system (WISP) to maintain orbits as low as 250km without drawing electrical power during steady state operation. This system utilizes an aqueous methyl alcohol propellant that passively evaporates across a phase separation boundary prior to exiting through a nozzle. Since this process occurs passively based on propellant evaporation properties and expansion chamber conditions, no electrical power is required during steady state operation. Theoretical calculations show that this system of 1U volume (10 x 10 x 10cm) is capable of providing sufficient thrust to maintain orbit for approximately 30 days