Improving time-efficiency in blocking expanding ring search for mobile ad hoc networks

We propose a new strategy for reducing the amount of latency and energy consumption in Blocking Expanding Ring Search (BERS) and enhanced Blocking Expanding Ring Search (BERS*) for mobile ad hoc networks (MANETs). BERS and BERS* are respectively energy and energy–time efficient route discovery protocols for MANETs as compared to conventional Expanding Ring Search (ERS). In this study, we identify unnecessary waiting time caused by a STOP/END instruction in BERS/BERS* and explore the potential of further improvement of their time efficiency. This leads to tBERS and tBERS*, the improved BERS and BERS* respectively. In tBERS/tBERS*, a route node may also issue the STOP/END instruction to terminate flooding. We implement this idea in algorithms, conduct analysis, and achieve further latency reduction in both tBERS and tBERS* as well as the energy saving in tBERS*.     

Viscous quark‐gluon plasma in the early universe

In the present work a study is given for the evolution of a flat, isotropic and homogeneous Universe, which is filled with a causal bulk viscous cosmological fluid. We describe the viscous properties by an ultra‐relativistic equation of state, and bulk viscosity coefficient obtained from recent lattice QCD calculations. The basic equation for the Hubble parameter is derived by using the energy equation obtained from the assumption of the covariant conservation of the energy‐momentum tensor of the matter in the Universe. By assuming a power law dependence of the bulk viscosity coefficient, temperature and relaxation time on the energy density, we derive the evolution equation for the Hubble function. By using the equations of state from recent lattice QCD simulations and heavy‐ion collisions we obtain an approximate solution of the field equations. In this treatment for the viscous cosmology, no evidence for singularity is observed. For example, both the Hubble parameter and the scale factor are finite at t = 0, where t is the comoving time. Furthermore, their time evolution essentially differs from the one associated with non‐viscous and ideal gas. Also it is noticed that the thermodynamic quantities, like temperature, energy density and bulk pressure remain finite. Particular solutions are also considered in order to prove that the free parameter in this model does qualitatively influence the final results.     

Gravitational field of a tachyon in a de Sitter universe

An exact solution of Einstein’s equations is interpreted as describing the gravitational field of a tachyon in a de Sitter universe. Switching off the cosmological constant yields the gravitational field of a tachyon in flat spacetime background.     

Radiating Kerr particle in Einstein universe

A generalized Kerr-NUT type metric is considered in connection with Einstein field equations corresponding to perfect fluid plus a pure radiation field. A general scheme for obtaining the exact solutions of these field equations is developed. Two physically meaningful particular cases are investigated in detail. One gives the field of a radiating Kerr particle embedded in the Einstein universe. The other solution may probably represent a deSitter-like universe pervaded by a pure radiation field.     

Relativistic Kinematic Honeycombs

In this paper, we study the honeycombs of the relativistic velocities space using the fact that this space has a hyperbolic space structure. For the three-dimensional case there are only four of these honeycombs with bounded cells and, since in this space there is a characteristic length, the cells have a fixed size. This fact, strongly limit the possible relative velocities between the vertices of the honeycombs. We consider as a possible application to cosmology the interpretation of these honeycombs as discrete large scale mass distribution.     

基于单片机的温度控制系统的设计

针对单片机温度控制系统采用传统控制方法容易出现响应速度慢、振荡剧烈、控制精度低等问题,对单片机温度控制系统的硬件电路、控制精度、控制算法等方面进行了设计研究。基于以AT89C51单片机为核心运用DS18B20温度传感器的温度控制系统,提出了变论域模糊PID控制算法,将变论域模糊控制和PID控制相结合,结合生猪猪舍温度控制系统对传统PID控制算法以及变论域模糊PID控制进行对比分析。实验结果表明,设计的温度控制系统采用了变论域模糊PID控制算法,提高了控制精度,加快了系统的响应速度,从而增强了温度控制系统的实用性,产生了重要的实际工程意义。     

宇宙核时钟不确定度的研究

基于经典快过程理论模型, 研究了原子核物理输入量的不确定性对Th/U, Th/Hf, Th/Eu, Th/Os, Th/Ir等核时钟估算宇宙年龄的影响. 其中利用蒙特卡罗模拟方法, 计算了不同质量模型下由单中子分离能引起的不确定性.结果表明, Th/U核时钟由原子核质量不确定性引起的误差大约为1.66 Ga, 比其他核时钟小2 Ga以上.对 Th/Eu, Th/Os和Th/Ir核时钟, 该误差分别为5.15, 3.93和3.95 Ga.由于Th/Hf核时钟受质量模型影响太大, 而Th/Os和Th/Ir的计算结果又明显偏大, 因此在年龄计算中都需谨慎使用.综合考虑原子核物理输入量和天文观测带来的误差, 利用Th/U核时钟估算的宇宙年龄为14.1± 3.8 Ga.     

One Electron Atom in Special Relativity with de Sitter Space-Time Symmetry (II)：—Higher Order Contributions

This is a follow of previous work entitled "One Electron Atom in Special Relativity with de Sitter Space-Time Symmetry" [Commun. Theor. Phys. 57 (2012) 930]. In this paper, we consider the higher order calculations and contributions in the previous framework to solve one electron atoms in de Sitter invariant relativistic quantum mechanics. The next-to-leading-order calculations in 1/R²-expansions show that the fine-structure constant α is variant with cosmologic time going by in the de Sitter invariant special relativistic quantum mechanics with standard FRW cosmologic model.     

A cyclic universe with colour fields

The topology of the universe is discussed in relation to the singularity problem. We explore the possibility that the initial state of the universe might have had a structure with 3-Klein bottle topology, which would lead to a model of a nonsingular oscillating (cyclic) universe with a well-defined boundary condition. The same topology is assumed to be intrinsic to the nature of the hypothetical primitive constituents of matter (usually called preons) giving rise to the observed variety of elementary particles. Some phenomenological implications of this approach are also discussed.