A New Method to Determine Central Wavelength and Optimal Bandwidth for Predicting Plant Nitrogen Uptake in Winter Wheat

Plant nitrogen （N） uptake is a good indicator of crop N status. In this study, a new method was designed to determine the central wavelength, optimal bandwidth and vegetation indices for predicting plant N uptake （g N m-2） in winter wheat （Triticum aestivum L.）. The data were collected from the ground-based hyperspectral reflectance measurements in eight field experiments on winter wheat of different years, eco-sites, varieties, N rates, sowing dates, and densities. The plant N uptake index （PNUI） based on NDVI of 807 nm combined with 736 nm was selected as the optimal vegetation index, and a linear model was developed with R2 of 0.870 and RMSE of 1.546 g N m-2 for calibration, and R2 of 0.834, RMSE of 1.316 g N m-2, slope of 0.934, and intercept of 0.001 for validation. Then, the effect of the bandwidth of central wavelengths on model performance was determined based on the interaction between central wavelength and bandwidth expansion. The results indicated that the optimal bandwidth varies with the changes of the central wavelength and with the interaction between the two bands in one vegetation index. These findings are important for prediction and diagnosis of plant N uptake more precise and accurate in crop management.

Energy and Bandwidth Based Link Stability Routing Algorithm for IoT

Internet of Things(IoT)is becoming popular nowadays for collecting and sharing the data from the nodes and among the nodes using internet links.Particularly,some of the nodes in IoT are mobile and dynamic in nature.Hence maintaining the link among the nodes,efficient bandwidth of the links among the mobile nodes with increased life time is a big challenge in IoT as it integrates mobile nodes with static nodes for data processing.In such networks,many routing-problems arise due to difficulties in energy and bandwidth based quality of service.Due to the mobility and finite nature of the nodes,transmission links between intermediary nodes may fail frequently,thus affecting the routing-performance of the network and the accessibility of the nodes.The existing protocols do not focus on the transmission links and energy,bandwidth and link stability of the nodes,but node links are significant factors for enhancing the quality of the routing.Link stability helps us to define whether the node is within or out of a coverage range.This paper proposed an Optimal Energy and bandwidth based Link Stability Routing(OEBLS)algorithm,to improve the link stable route with minimized error rate and throughput.In this paper,the optimal route from the source to the sink is determined based on the energy and bandwidth,link stability value.Among the existing routes,the sink node will choose the optimal route which is having less link stability value.Highly stable link is determined by evaluating link stability value using distance and velocity.Residual-energy of the node is estimated using the current energy and the consumed energy.Consumed energy is estimated using transmitted power and the received power.Available bandwidth in the link is estimated using the idle time and channel capacity with the consideration of probability of collision.

An Adaptive Bandwidth Allocation for Energy Efficient Wireless Communication Systems

In this paper, an energy efficient bandwidth allocation scheme is proposed for wireless communication systems. An optimal bandwidth expansion（OBE） scheme is proposed to assign the available system bandwidth for users. When the system bandwidth does not reach the full load, the remaining bandwidth can be energy-efficiently assigned to the other users. Simulation results show that the energy efficiency of the proposed OBE scheme outperforms the traditional same bandwidth expansion（SBE） scheme. Thus, the proposed OBE can effectively assign the system bandwidth and improve energy efficiency.

Cross-layer resource allocation based on equivalent bandwidth in OFDMA systems

A quality of service（QoS） guaranteed cross-layer resource allocation algorithm with physical layer, medium access control（MAC） layer and call admission control（CAC） considered simultaneously is proposed for the full IP orthogonal frequency division multiple access（OFDMA） communication system, which can ensure the quality of multimedia services in full IP networks.The algorithm converts the physical layer resources such as subcarriers, transmission power, and the QoS metrics into equivalent bandwidth which can be distributed by the base station in all three layers. By this means, the QoS requirements in terms of bit error rate（BER）, transmission delay and dropping probability can be guaranteed by the cross-layer optimal equivalent bandwidth allocation. The numerical results show that the proposed algorithm has higher spectrum efficiency compared to the existing systems.

Neural Network Optimization of Multivariate KDE Bandwidth for Buoy Spatial Information

It is one of the responsibilities of the navigation support department to ensure the correct layout position of the light buoy and provide as accurate position information as possible for ship navigation and positioning.If the position deviation of the light buoy is too large to be detected in time,sending wrong navigation assistance information to the ship will directly affect the navigation safety of the ship and increase the pressure on the management department.Therefore,mastering the offset characteristics of light buoy is of great significance for the maintenance of light buoy and improving the navigation aid efficiency of light buoy.Kernel density estimation can intuitively express the spatial and temporal distribution characteristics of buoy position,and indicates the intensive areas of buoy position in the channel.In this paper,in order to speed up deciding the optimal variable width of kernel density estimator,an improved adaptive variable width kernel density estimator is proposed,which reduces the risk of too smooth probability density estimation phenomenon and improves the estimation accuracy of probability density.A fractional recurrent neural network is designed to search the optimal bandwidth of kernel density estimator.It not only achieves faster training speed,but also improves the estimation accuracy of probability density.

A low-noise PLL design achieved by optimizing the loop bandwidth

This paper describes a low-noise phase-locked loop （PLL） design method to achieve minimum jitter. Based on the phase noise properties extracted from the transistor, and the low-pass or high-pass transfer characteristics of different noise sources to the output, an optimal loop bandwidth design method, derived from a continuous-time PLL model, further improves the jitter characteristics of the PLL. The described method not only finds the optimal loop-bandwidth to minimize the overall PLL jitter, but also achieves optimal loop-bandwidth by changing the value of the resistor or charge pump current. In addition, a phase-domain behavioral model in ADS is presented for accurately predicting improved jitter performance of a PLL at system level. A prototype PLL designed in a 0.18 μm CMOS technology is used to investigate the accuracy of the theoretical predictions. The simulation shows significant performance improvement by using the proposed method. The simulated RMS and peak-to-peak jitter of the PLL at the optimal loop-bandwidth are 10.262 ps and 46.851 ps, respectively.

Designing broadband fiber optic parametric amplifier based on near-zero single ZDW PCF with ultra-flat nature

We propose a broadband fiber optic parametric amplifier（FOPA） based on a near-zero ultra-flat dispersion profile with a single zero-dispersion wavelength（ZDW） by using a selective liquid infiltration technique.The amplifier gain and bandwidth is investigated for a variety of fiber lengths, pump power, and operating wavelengths. It is observed that sufficient peak gains and broader bandwidths can be achieved with a small negative anomalous dispersion（β2≤ 0） and a positive value of the 4th-order dispersion parameter（t β4）around the pump. We can optimize an FOPA with a bandwidth of more than 220 nm around the communications wavelength.