523 research outputs found
Computations of Floer Homology for certain Lagrangian Tori in closed 4-manifolds
We compute the Lagrangian Floer cohomology groups of certain tori in closed
simply connected symplectic 4-manifolds arising from Fintushel-Stern knot
surgery. These manifolds are usually not symplectically aspherical. As a result
of the computation we observe examples where and
and are smoothly isotopic but are not symplectically isotopic
and are distinguished by .Comment: changes based on reviewer's comment
A novel mobile communication system using Pulse Position based Chirp Spread Spectrum modulation
The paper presents a new mobile communication system based on Chirp Spread Spectrum (CSS) transmission. The downlink modulation scheme is extended with Pulse Position Modulation (PPM) to carry data for multiple mobile terminals simultaneously. The described novel mechanism ensures reliable and robust communication between the parties, especially for terminals moving with high speeds or at long range. Furthermore, the proposed system take care of the uplink communication as well, where Closed-Loop Power Control (CLPC) is applied to handle the near-far problem and improve the performance of the system. Based on the attributes of the proposed system the application area covers sensor networks, IoT applications and Industry 4.0 as general field of LPWAN, however, mobility of terminals also considered.Analytical investigations for downlink communication are described focusing on the instantaneous symbol-error rate and average SER in Rayleigh fading channel. The results show that the proposed Pulse Position based Chirp Spread Spectrum technique for Multiple Access (shortly PP-CSS-MA) allows higher data rates that is used for the multiple access feature. In addition, numerical results are presented as well, and they point out the benefits of the applied CLPC mechanism. Finally, considerations regarding to the implementation of the proposed communication system are described
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Pulmonary Kaposi Sarcoma without Mucocutaneous Involvement: The Role of Sequential Thallium and Gallium Scintigraphy.
Kaposi sarcoma (KS) is a vascular-related tumor that has been associated with human immunodeficiency virus (HIV). It commonly involves the skin and lymph nodes, and infrequently involves the lungs. In very rare instances, pulmonary KS can be found in the absence of endobronchial and mucocutaneous involvement. Utilization of sequential thallium and gallium scintigraphy can aid in the diagnosis of pulmonary KS in the absence of mucocutaneous and endobronchial involvement. In this report, we discuss a case of a patient with acquired immunodeficiency syndrome who presented with dyspnea and cough and was found to have subtle pulmonary parenchymal nodular airspace opacities. He underwent negative infectious evaluation, including bronchoscopy. Despite the absence of mucocutaneous findings, sequential positive thallium and negative gallium scintigraphy led to an early diagnosis of pulmonary KS. Pulmonary KS in the absence of mucocutaneous involvement is a rare finding that is exceedingly difficult to diagnose. However, pulmonary KS should be considered in patients with HIV who present with respiratory symptoms even if the typical mucocutaneous manifestations of KS are absent. In such circumstances, sequential thallium and gallium scintigraphy can help differentiate pulmonary KS from other processes such as infections and lymphoma, and assist in establishing an earlier diagnosis
A novel mobile communication system using Pulse Position based Chirp Spread Spectrum modulation
The paper presents a new mobile communication system based on Chirp Spread Spectrum (CSS) transmission. The downlink modulation scheme is extended with Pulse Position Modulation (PPM) to carry data for multiple mobile terminals simultaneously. The described novel mechanism ensures reliable and robust communication between the parties, especially for terminals moving with high speeds or at long range. Furthermore, the proposed system take care of the uplink communication as well, where Closed-Loop Power Control (CLPC) is applied to handle the near-far problem and improve the performance of the system. Based on the attributes of the proposed system the application area covers sensor networks, IoT applications and Industry 4.0 as general field of LPWAN, however, mobility of terminals also considered.Analytical investigations for downlink communication are described focusing on the instantaneous symbol-error rate and average SER in Rayleigh fading channel. The results show that the proposed Pulse Position based Chirp Spread Spectrum technique for Multiple Access (shortly PP-CSS-MA) allows higher data rates that is used for the multiple access feature. In addition, numerical results are presented as well, and they point out the benefits of the applied CLPC mechanism. Finally, considerations regarding to the implementation of the proposed communication system are described
A continuum path integral approach to the simulation of a unitary gas
This thesis presents an investigation by simulation of a unpolarized fermionic unitary gas system composed of two interacting fermionic species. While these species do not interact amongst themselves, they interact with each other using a pairwise zero-range delta function potential that has been tuned to unitarity i.e.the scattering length . A path integral Monte Carlo simulation of such a system is performed using an exact novel zero-range, delta function pair propagator which has been tuned to the unitary limit so that essentially all interactions amongst the interacting particles are comprised of s-wave interactions. This tuning in some sense yields the simplest imaginable interacting fermionic system which out to display features that would apply universally to interacting fermionic particles with particular interest within this field of study being in understanding the unitary BCS-BEC crossover. Numerical and ergodic challenges to sampling a divergent approximate path integral are discussed and solutions are proposed, implemented and explored. This thesis represents a step closer to this understanding by investigating this system with this novel propagator in a fixed-node path integral Monte Carlo framework and comparing to earlier work
Optimal control inputs for fuel economy and emissions of a series hybrid electric vehicle
Hybrid electric vehicles offer significant fuel economy benefits, because battery and fuel can be used as complementing energy sources. This paper presents the use of dynamic programming to find the optimal blend of power sources, leading to the lowest fuel consumption and the lowest level of harmful emissions. It is found that the optimal engine behavior differs substantially to an on-line adaptive control system previously designed for the Lotus Evora 414E. When analyzing the trade-off between emission and fuel consumption, CO and HC emissions show a traditional Pareto curve, whereas NOx emissions show a near linear relationship with a high penalty. These global optimization results are not directly applicable for online control, but they can guide the design of a more efficient hybrid control system
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