Comparison of Different Antenna Arrays for the Channel Capacity

[[abstract]]Three types of antenna arrays such as uniform linear, uniform rectangular arrays and uniform cube arrays are used in the transmitter and their corresponding channel capacity on several paths in the indoor environment are calculated. Numerical results show that uniform linear arrays is better than that for uniform rectangular arrays and uniform cube arrays system with and without interference.[[notice]]補正完

A Novel DS-UWB Pulses Design Using Genetic Algorithm

[[abstract]]This paper proposes a new pulse design method to improve spectrum utilization rate and reduce the outage probability in ultra wide band (UWB) system. Several third derivative Gaussian waveforms are employed to generate the pulse based on the bandwidth constraint set by the US Federal Communications Commission (FCC) mask. The genetic algorithm (GA) is used to find the optimal pulse parameter. This method is an easy way to achieve in practical circuit implementation compared to one pulse generator, since COMS circuit is hard to produce one pulse with short duration and complex pulse shape. Comparisons with the traditional Gaussian pulse, the synthesis pulse by GA not only satisfy the FCC emission mask but also have high spectrum utilization rate. Simulation results show that the performances in indoor UWB system using the synthesis pulse by GA is better than that using traditional Gaussian pulse. Numerical results show that the synthesis pulse by GA is higher 30 percent of spectrum utilization rate and lower 65 percent of outage probability for the same transmission power, as well as lower 21 percent of outage probability for fixed signal-to-noise ratio (SNR)at the receiver comparing with traditional Gaussian pulse. This proposed method not only use in indoor UWB system but also can extend to different communication system just changing the system object function.[[conferencetype]]國際[[conferencedate]]20090403~20090405[[iscallforpapers]]Y[[conferencelocation]]Kuala Lumpar, Malaysi

Channel Capacities of Indoor MIMO-UWB Transmission for Different Material Partitions

[[abstract]]In this paper, channel capacities of indoor MIMO-UWB (multiple input multiple output-Ultra wideband) transmission for different material partitions are described. A ray-tracing technique is applied to compute the frequency responses for an environment with different material partitions. All the material parameters of our simulation environments such as dielectric constant and conductivity are both dependent on operating frequency in our calculations for UWB transmission. In other words, these material parameters are frequency selective for our calculation. By frequency responses of our simulation environment, channel capacities of MIMO-UWB transmission are calculated. Furthermore, outage probability is also computed for analyzing statistical property. Based on the calculations, the effects by different material partitions on 2X2 MIMO-UWB transmission are compared for different signal power to noise power ratio (SNR). In addition, the effects by different material partitions for different antenna array are investigated and compared to SISO (single input single output). Numerical results show that the Styrofoam partition has largest transmission rate, and the plywood partition has smallest one. Finally, it is worth noting that in these cases the present work provided not only comparative information but also quantitative information.[[notice]]補正完畢[[incitationindex]]E

Path Loss Reduction for Multiusers by Different Antenna Arrays

[[abstract]]In this paper, we use the shooting and bouncing ray/image (SBR/Image)[1]-[5] method to compute the path loss for different outdoor environments. Three types of antenna arrays such as L shape, Y shape, and Circular shape arrays are used in the base station and their corresponding path loss on several routes in the outdoor environment are calculated[6]-[8]. Moreover, the genetic algorithm (GA) and Dynamic Differential Evolution (DDE) are employed to optimize the excitation voltages and phases for antenna arrays to form proper antenna patterns[9], [10]. The particle swarm optimization algorithm has better optimization result than genetic algorithm in NLOS case. For antenna arrays Y shape has better optimization result in NLOS case.[[conferencetype]]國際[[conferencedate]]20140714~20140718[[conferencelocation]]Arusha, Tanzani

Hunting for Heavy Majorana Neutrinos with Lepton Number Violating Signatures at LHC

The neutrinophilic two-Higgs-doublet model ($\nu$2HDM) provides a natural way to generate tiny neutrino mass from interactions with the new doublet scalar $\Phi_\nu$ ($H^\pm,~H,~A$) and singlet neutrinos $N_R$ of TeV scale. In this paper, we perform detailed simulations for the lepton number violating (LNV) signatures at LHC arising from cascade decays of the new scalars and neutrinos with the mass order $m_{N_R}<m_{\Phi_\nu}$. Under constraints from lepton flavor violating processes and direct collider searches, their decay properties are explored and lead to three types of LNV signatures: $2\ell^\pm 4j+\cancel{E}_T$, $3\ell^\pm 4j+\cancel{E}_T$, and $3\ell^\pm\ell^\mp 4j$. We find that the same-sign trilepton signature $3\ell^\pm4j+\cancel{E}_T$ is quite unique and is the most promising discovery channel at the high-luminosity LHC. Our analysis also yields the $95\%$ C.L. exclusion limits in the plane of the $\Phi_\nu$ and $N_R$ masses at 13 (14) TeV LHC with an integrated luminosity of 100~(3000)/fb.Comment: 31 pages, 17 figures, 6 tables; v2: added a few refs and updated one ref, without other change

Optimal Relay Antenna Location in Indoor Environment Using Particle Swarm Optimizer and Genetic Algorithm

[[abstract]]An optimization procedure for the location of the relay transceiver in ultra-wideband wireless communication system is presented. The impulse responses of different transceiver locations are computed by shooting and bouncing ray/image (SBR/Image) techniques and inverse fast Fourier transform (IFFT). By using the impulse responses of these multi-path channels, the bit error rate (BER) performance for binary pulse amplitude modulation (BPAM) impulse radio UWB communication system are calculated. Based on the BER performance, the outage probability for any given relay location of the transceiver can be computed. The optimal relay antenna location for minimizing the outage probability is searched by genetic algorithm (GA) and particle swarm optimizer (PSO). The transmitter is in the center of the whole indoor environment and the receivers are uniform distributed with 1.5 meter intervals in the whole indoor environment. Two cases are considered as following: (I) Two relay transceivers with two different cases are employed. First, the whole space is divided into two areas and one relay transceiver is used in each area. The optimal relay antenna locations are searched in each area respectively. Second, the two optimal relay locations are searched in the whole space directly without any prior division. (II) Four relay transceivers with two different cases are employed. First, the whole space is divided into four areas and one relay transceiver is used in each area. The optimal relay antenna locations are searched in each area respectively. Second, the four optimal relay locations are searched in the whole space directly without any prior division. Numerical results have shown that our proposed method is effective for finding the optimal location for relay antenna to reduce BER and outage probability.[[notice]]補正完畢[[incitationindex]]SCI[[booktype]]紙

Location Optimization for Antennas by Asynchronous Particle Swarm Optimization

[[abstract]]A novel optimisation procedure for the location of the transmitter in 3 × 3 multiple input multiple output wireless local area network wireless communication systems is presented. The optimal antenna location for maximising the channel capacity is searched by particle swarm optimiser (PSO) and asynchronous particle swarm optimisation (APSO). There are two different receiver locations considered in the simulation. These two cases are: (i) the transmitter is mobile in the whole indoor environment and the receivers are located on the tables spaced in intervals uniformly distributed (ii) the transmitter is mobile and the receivers are space in uniformly distributed intervals in the whole indoor environment. Numerical results have shown that the proposed PSO and APSO methods are transmit antenna location is optimised to increase channel capacity. The APSO has better optimisation results compared with the PSO and numerical results also show that the APSO outperforms the PSO in convergence speed.[[notice]]補正完畢[[incitationindex]]SCI[[booktype]]紙本[[booktype]]電子

Comparison of Dynamic Differential Evolution and Genetic Algorithm for MIMO-WLAN Transmitter Antenna Location in Indoor Environment

[[abstract]]A novel optimization procedure for the location of the transmitter in 3×33×3 multiple input multiple output (MIMO) wireless local area network (WLAN) wireless communication systems is presented. The optimal antenna location for maximizing the channel capacity is searched by dynamic differential evolution (DDE) and genetic algorithm (GA). There are two different receiver locations considered in the simulation. The receivers are located with uniform intervals distribution either on the tables or in the whole indoor environment. Numerical results show that the performance for increasing channel capacity by DDE algorithm is better than that by GA.[[notice]]補正完畢[[incitationindex]]SCI[[incitationindex]]EI[[booktype]]電子版[[booktype]]紙

Water, rather than temperature, dominantly impacts how soil fauna affect dissolved carbon and nitrogen release from fresh litter during early litter decomposition

Longstanding observations suggest that dissolved materials are lost from fresh litter through leaching, but the role of soil fauna in controlling this process has been poorly documented. In this study, a litterbag experiment employing litterbags with different mesh sizes (3 mm to permit soil fauna access and 0.04 mm to exclude fauna access) was conducted in three habitats (arid valley, ecotone and subalpine forest) with changes in climate and vegetation types to evaluate the effects of soil fauna on the concentrations of dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) during the first year of decomposition. The results showed that the individual density and community abundance of soil fauna greatly varied among these habitats, but Prostigmata, Isotomidae and Oribatida were the dominant soil invertebrates. At the end of the experiment, the mass remaining of foliar litter ranged from 58% for shrub litter to 77% for birch litter, and the DOC and TDN concentrations decreased to 54%-85% and increased to 34%-269%, respectively, when soil fauna were not present. The effects of soil fauna on the concentrations of both DOC and TDN in foliar litter were greater in the subalpine forest (wetter but colder) during the winter and in the arid valley (warmer but drier) during the growing season, and this effect was positively correlated with water content. Moreover, the effects of fauna on DOC and TDN concentrations were greater for high-quality litter and were related to the C/N ratio. These results suggest that water, rather than temperature, dominates how fauna affect the release of dissolved substances from fresh litter