6,156 research outputs found
Yield Performance of Locally Selected Cocoa Clones in North Luwu
Participatory selection in North Luwu District selected some locally cocoa clones, of which MCC 01 and MCC 02 the most promising to be developed as clonal material. This research has objectives to observe the stability performance of yield of these clones that enable be characterized of the potency as the basis for recommendation. Observation were carried out in 35 selected-farms be differentiated according to clone\u27s type, namely MCC 01, MCC 02 and Sulawesi 01 (control) and the year of planting (age). These farms were establised at the main area of cocoa in North Luwu. The assessed variables were the number of pod, yield components, the resistance to cocoa pod borer (CPB), vascular-streak dieback (VSD) and phytophthora pod rot (PPR). Data were recorded through 20 sampled-trees per farm in the period of April 2013 to April 2014 with monthly basis assessment. Data were analyzed refer to Eberhart & Russel method to perform stability parameters of the yield. The results indicate that these clones stable performing yield potency among plant age. MCC 01 and MCC 02 performed yield potency in amount of 3,682 kg/ha and 3,132 kg/ha respectively higher than Sulawesi 01 of 2,772 kg/ha. Evaluation of the resistance, MCC 01 having moderate resistance to CPB and VSD and resistance to PPR, however MCC 02 having resistance to CPB, VSD and PPR. Referring to the potency thus MCC 01 and MCC 02 were legally recommended as clonal material for farmers, restricted at the agroclimatic area similar to the condition in North Luwu
Breathing Modes in Rotating Bose-Condensed Gas: An Exact Diagonalization Study
We present an exact diagonalization study of the breathing mode collective
excitations for a rotating Bose-Einstein condensate of spinless bosons
interacting via repulsive finite-range Gaussian potential and harmonically
confined in quasi-two-dimension. The yrast state and the low-lying excited
states are variationally obtained in given subspaces of the quantized total
angular momentum employing the beyond lowest Landau level approximation in
slowly rotating regime with . For a given , the low-energy
eigenspectra (bands) are obtained in weakly to moderately interacting regime.
Further, for a given interaction, the split in low-lying eigenenergies with
increasing is the precursor to spontaneous symmetry breaking of the
axisymmetry associated with the entry of the first vortex. With increase in
repulsive interaction, the value of the first breathing mode increases for
stable total angular momentum states L=0~\mbox{and}~N, but decreases for
intermediate metastable states. The position of the observed first
breathing modes in the eigenspectrum remains unchanged as the interaction is
varied over several orders of magnitude.Comment: 5 pages, 3 figures, RevTex two colum
Uplink capacity of a variable density cellular system with multicell processing
In this work we investigate the information theoretic capacity of the uplink of a cellular system. Assuming centralised processing for all base stations, we consider a power-law path loss model along with variable cell size (variable density of Base Stations) and we formulate an average path-loss approximation. Considering a realistic Rician flat fading environment, the analytical result for the per-cell capacity is derived for a large number of users distributed over each cell. We extend this general approach to model the uplink of sectorized cellular system. To this end, we assume that the user terminals are served by perfectly directional receiver antennas, dividing the cell coverage area into perfectly non-interfering sectors. We show how the capacity is increased (due to degrees of freedom gain) in comparison to the single receiving antenna system and we investigate the asymptotic behaviour when the number of sectors grows large. We further extend the analysis to find the capacity when the multiple antennas used for each Base Station are omnidirectional and uncorrelated (power gain on top of degrees of freedom gain). We validate the numerical solutions with Monte Carlo simulations for random fading realizations and we interpret the results for the real-world systems
Fairness Evaluation in Cooperative Hybrid Cellular Systems
Many method has been applied previously to improve the fairness of a wireless communication system. In this paper, we propose using hybrid schemes, where more than one transmission scheme are used in one system, to achieve this objective. These schemes consist of cooperative transmission schemes, maximal ratio transmission and interference alignment, and non-cooperative schemes, orthogonal and non-orthogonal schemes used alongside and in combinations in the same system to improve the fairness. We provide different weight calculation methods to vary the output of the fairness problem. We show the solution of the radio resource allocation problem for the transmission schemes used. Finally, simulation results is provided to show fairness achieved, in terms of Jain's fairness index, by applying the hybrid schemes proposed and the different weight calculation methods at different inter-site distances
A User Scheduling Scheme for Reducing Electromagnetic (EM) Emission in the Uplink of Mobile Communication Systems
The ubiquity and convergence of wireless communication services have contributed to an unprecedented popularity of mobile communications. Given that wireless communication systems operate on radiofrequency waves, the electromagnetic (EM) radiation exposure they generate is also unprecedented and, hence, this could have adverse health effects on both humans and animals according to the World Health Organization. In this paper, we propose a user scheduling/power allocation scheme to minimize the EM exposure of users subject to transmitting a target number of bits. Our user scheduling method is based on assigning priority levels to each user and the user with the lowest priority level is scheduled for transmission. Power allocation, on the other hand, is based on the water-filling approach over time by using the past channel gains of a user to compute its water level. Simulation results show that our proposed scheme performs much better than a spectral efficiency based scheme but has a higher EM emission in comparison with a non-practical ideal scheme
Delay-Optimal Relay Selection in Device-to-Device Communications for Smart Grid
The smart grid communication network adopts a hierarchical structure which consists of three kinds of networks which are Home Area Networks (HANs), Neighborhood Area Networks (NANs), and Wide Area Networks (WANs). The smart grid NANs comprise of the communication infrastructure used to manage the electricity distribution to the end users. Cellular technology with LTE-based standards is a widely-used and forward-looking technology hence becomes a promising technology that can meet the requirements of different applications in NANs. However, the LTE has a limitation to cope with the data traffic characteristics of smart grid applications, thus require for enhancements. Device-to-Device (D2D) communications enable direct data transmissions between devices by exploiting the cellular resources, which could guarantee the improvement of LTE performances. Delay is one of the important communication requirements for the real-time smart grid applications. In this paper, the application of D2D communications for the smart grid NANs is investigated to improve the average end-to-end delay of the system. A relay selection algorithm that considers both the queue state and the channel state of nodes is proposed. The optimization problem is formulated as a constrained Markov decision process (CMDP) and a linear programming method is used to find the optimal policy for the CMDP problem. Simulation results are presented to prove the effectiveness of the proposed scheme
Average energy efficiency contours with multiple decoding policies
This letter addresses energy-efficient design in multi-user, single-carrier uplink channels by employing multiple decoding policies. The comparison metric used in this study is based on average energy efficiency contours, where an optimal rate vector is obtained based on four system targets: Maximum energy efficiency, a trade-off between maximum energy efficiency and rate fairness, achieving energy efficiency target with maximum sum-rate and achieving energy efficiency target with fairness. The transmit power function is approximated using Taylor series expansion, with simulation results demonstrating the achievability of the optimal rate vector, and negligible performance difference in employing this approximation
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