Introducing an Age-Varying Fitness Estimation Function

2013 ◽  
pp. 59-71 ◽  
Author(s):  
Babak Hodjat ◽  
Hormoz Shahrzad
Keyword(s):  
Estimation Function

A Novel Header Bits Estimation Scheme for H.264/AVC Standard

2013 ◽  
Vol 333-335 ◽  
pp. 787-790
Author(s):  
Shu Qian He ◽  
Zheng Jie Deng ◽  
Chun Shi
Keyword(s):  
Rate Control ◽  
Rate Distortion ◽  
Accurate Estimation ◽  
Rate Estimation ◽  
Proposed Model ◽  
Estimation Function ◽  
Estimation Scheme ◽  
Block Based ◽  
Coding Bits ◽  
Distortion Rate

Rate estimation is useful for many H.264/AVC applications including rate-distortion optimization (RDO) for fast mode decision and precise rate control. In this paper, we propose a new header rate prediction model and an adaptive algorithm to provide more accurate estimation of the number of total coding bits for rate control compared to previously proposed methods. The header bit rate estimation is modeled by a linear combination of the number of mode block, and the sum of absolute values of all motion vectors for each block. Based on the proposed model, a header rate estimation function is also proposed to give a more accurate rate-distortion rate control. The proposed schemes can achieve better results in rate-distortion and rate control to previously proposed approaches.

Optimal path planning with modified A-Star algorithm for stealth unmanned aerial vehicles in 3D network radar environment

2021 ◽  
pp. 095441002110073
Author(s):  
Zhe Zhang ◽  
Jian Wu ◽  
Jiyang Dai ◽  
Cheng He
Keyword(s):  
Path Planning ◽  
Unmanned Aerial Vehicles ◽  
Optimal Path ◽  
Radar System ◽  
Planning Method ◽  
Optimal Path Planning ◽  
Aerial Vehicles ◽  
3D Network ◽  
Planning Scheme ◽  
Estimation Function

For stealth unmanned aerial vehicles (UAVs), path security and search efficiency of penetration paths are the two most important factors in performing missions. This article investigates an optimal penetration path planning method that simultaneously considers the principles of kinematics, the dynamic radar cross-section of stealth UAVs, and the network radar system. By introducing the radar threat estimation function and a 3D bidirectional sector multilayer variable step search strategy into the conventional A-Star algorithm, a modified A-Star algorithm was proposed which aims to satisfy waypoint accuracy and the algorithm searching efficiency. Next, using the proposed penetration path planning method, new waypoints were selected simultaneously which satisfy the attitude angle constraints and rank-K fusion criterion of the radar system. Furthermore, for comparative analysis of different algorithms, the conventional A-Star algorithm, bidirectional multilayer A-Star algorithm, and modified A-Star algorithm were utilized to settle the penetration path problem that UAVs experience under various threat scenarios. Finally, the simulation results indicate that the paths obtained by employing the modified algorithm have optimal path costs and higher safety in a 3D complex network radar environment, which show the effectiveness of the proposed path planning scheme.

scholarly journals Estimating primary energy of cosmic rays by calculating secondary particles density in optimum distance from shower core

2018 ◽  
Vol 27 (02) ◽  
pp. 1750190
Author(s):  
G. Rastegarzadeh ◽  
L. Rafezi
Keyword(s):  
Primary Particle ◽  
Primary Energy ◽  
Energy Estimation ◽  
Array Configuration ◽  
Secondary Particles ◽  
Shower Core ◽  
Optimum Distance ◽  
Array Detectors ◽  
Estimation Function ◽  
Minimum Uncertainty

Optimum distance (R[Formula: see text]) is a distance from the shower core in which the density calculated by lateral distribution function, has its minimum uncertainty. In this paper, using CORSIKA code, proton, carbon and iron primary in the energy range between 10[Formula: see text]–[Formula: see text][Formula: see text]eV are simulated to find R[Formula: see text] for Alborz-I array located at an altitude of 1200[Formula: see text]m above sea level. It is shown that R[Formula: see text] is approximately independent of characteristics of primary particle and it is only dependent to array configuration. Dependency of R[Formula: see text] on layout and detector spacing for 20 Alborz-I array detectors, are studied. It is shown that the Alborz-I array layout and its detector spacing result into the best (minimum uncertainty) R[Formula: see text] for its number of detectors. In this work, R[Formula: see text] for Alborz-I array is obtained about [Formula: see text][Formula: see text]m (from NKG function) and [Formula: see text][Formula: see text]m (from NKG type function). In addition, it is shown that, by finding dependency of primary energy to density in optimum distance, energy of primary particle can be estimated well. An energy estimation function is suggested and the function is examined by another set of simulated showers.

scholarly journals An Adaptive Wake-Up-Interval to Enhance Receiver-Based Ps-Mac Protocol for Wireless Sensor Networks

Sensors ◽  
2019 ◽  
Vol 19 (17) ◽  
pp. 3732 ◽  
Author(s):  
Mohammed Sani Adam ◽  
Lip Yee Por ◽  
Mohammad Rashid Hussain ◽  
Nawsher Khan ◽  
Tan Fong Ang ◽  
...  
Keyword(s):  
Mac Protocol ◽  
Wireless Sensor ◽  
Delivery Ratio ◽  
Adaptive Function ◽  
Medium Access ◽  
Essential Information ◽  
Initial Control ◽  
Estimation Function ◽  
Reduce Energy Consumption ◽  
Traffic Estimation

Many receiver-based Preamble Sampling Medium Access Control (PS-MAC) protocols have been proposed to provide better performance for variable traffic in a wireless sensor network (WSN). However, most of these protocols cannot prevent the occurrence of incorrect traffic convergence that causes the receiver node to wake-up more frequently than the transmitter node. In this research, a new protocol is proposed to prevent the problem mentioned above. The proposed mechanism has four components, and they are Initial control frame message, traffic estimation function, control frame message, and adaptive function. The initial control frame message is used to initiate the message transmission by the receiver node. The traffic estimation function is proposed to reduce the wake-up frequency of the receiver node by using the proposed traffic status register (TSR), idle listening times (ILTn, ILTk), and “number of wake-up without receiving beacon message” (NWwbm). The control frame message aims to supply the essential information to the receiver node to get the next wake-up-interval (WUI) time for the transmitter node using the proposed adaptive function. The proposed adaptive function is used by the receiver node to calculate the next WUI time of each of the transmitter nodes. Several simulations are conducted based on the benchmark protocols. The outcome of the simulation indicates that the proposed mechanism can prevent the incorrect traffic convergence problem that causes frequent wake-up of the receiver node compared to the transmitter node. Moreover, the simulation results also indicate that the proposed mechanism could reduce energy consumption, produce minor latency, improve the throughput, and produce higher packet delivery ratio compared to other related works.

scholarly journals Earth-to-Earth Microwave Rain Attenuation Measurements: A Survey On the Recent Literature

Symmetry ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1440
Author(s):  
Vasilis Christofilakis ◽  
Giorgos Tatsis ◽  
Spyridon K. Chronopoulos ◽  
Alexandros Sakkas ◽  
Anastasios G. Skrivanos ◽  
...  
Keyword(s):  
Rainfall Intensity ◽  
Recent Literature ◽  
Theoretical Models ◽  
Rain Attenuation ◽  
Research Topic ◽  
Literature Survey ◽  
Future Trends ◽  
Signal Attenuation ◽  
Innovative Idea ◽  
Estimation Function

Many works have been conducted relevant to rainfall measurements, while the first relevant ones were based on the power loss estimation function from wireless links located back to the early 1940s. It is notable, though, that this innovative idea conduced to many theoretical models correlating the signal attenuation to the rainfall intensity. This type of parameter strongly contributes to the mechanism of frequency attenuation above 10 GHz. Consequently, in the last twenty years, there has been a significant boost to this research topic. Researchers all around the world have worked thoroughly on the issue of estimating rain with the use of earth-to-earth microwave signal attenuation. Nevertheless, the issue remains intriguing and challenging. This paper presents a literature survey, of the last decade, on this challenging issue focusing on measurements from backhaul cellular microwave links and experimental setups. Research challenges and future trends are also presented.

scholarly journals A Fast Method for Estimating the Number of Clusters Based on Score and the Minimum Distance of the Center Point

Information ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 16
Author(s):  
Zhenzhen He ◽  
Zongpu Jia ◽  
Xiaohong Zhang
Keyword(s):  
Minimum Distance ◽  
Learning Algorithm ◽  
Kernel Density ◽  
Gaussian Kernel ◽  
Data Sets ◽  
Fast Method ◽  
Number Of Clusters ◽  
Center Point ◽  
Estimation Function ◽  
Candidate Set

Clustering is widely used as an unsupervised learning algorithm. However, it is often necessary to manually enter the number of clusters, and the number of clusters has a great impact on the clustering effect. At present, researchers propose some algorithms to determine the number of clusters, but the results are not very good for determining the number of clusters of data sets with complex and scattered shapes. To solve these problems, this paper proposes using the Gaussian Kernel density estimation function to determine the maximum number of clusters, use the change of center point score to get the candidate set of center points, and further use the change of the minimum distance between center points to get the number of clusters. The experiment shows the validity and practicability of the proposed algorithm.

scholarly journals Calibration of MEMS Triaxial Accelerometers Based on the Maximum Likelihood Estimation Method

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Yifan Sun ◽  
Xiang Xu
Keyword(s):  
Maximum Likelihood ◽  
Maximum Likelihood Estimation ◽  
Random Noise ◽  
Estimation Method ◽  
Likelihood Estimation ◽  
Least Square ◽  
Triaxial Accelerometer ◽  
Zero Bias ◽  
Estimation Function ◽  
Maximum Likelihood Estimation Method

As a widely used inertial device, a MEMS triaxial accelerometer has zero-bias error, nonorthogonal error, and scale-factor error due to technical defects. Raw readings without calibration might seriously affect the accuracy of inertial navigation system. Therefore, it is necessary to conduct calibration processing before using a MEMS triaxial accelerometer. This paper presents a MEMS triaxial accelerometer calibration method based on the maximum likelihood estimation method. The error of the MEMS triaxial accelerometer comes into question, and the optimal estimation function is established. The calibration parameters are obtained by the Newton iteration method, which is more efficient and accurate. Compared with the least square method, which estimates the parameters of the suboptimal estimation function established under the condition of assuming that the mean of the random noise is zero, the parameters calibrated by the maximum likelihood estimation method are more accurate and stable. Moreover, the proposed method has low computation, which is more functional. Simulation and experimental results using the consumer low-cost MEMS triaxial accelerometer are presented to support the abovementioned superiorities of the maximum likelihood estimation method. The proposed method has the potential to be applied to other triaxial inertial sensors.

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