scholarly journals Research on Multibeam Pattern Synthesis of Time Modulated Array Based on Convex Optimization

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Jiawen Hu ◽  
Xikuan Dong ◽  
Jing Tan ◽  
Yachao Jiang ◽  
Hailin Li
Keyword(s):  
Convex Optimization ◽  
Dynamic Range ◽  
Linear Array ◽  
Synthesis Method ◽  
Optimization Method ◽  
Center Frequency ◽  
Pattern Synthesis ◽  
Beam Radiation ◽  
Second Stage ◽  
Two Stages

An efficient multibeam pattern synthesis method for time modulated array (TMA) is proposed in this paper. The aim of this method is to generate a beam pattern on the specified sideband of TMA. The pattern synthesis problem is divided into two stages. In the first stage, the sequential convex optimization method is used to suppress the sidelobe of the center frequency and reduce the amplitude dynamic range ratios (DRR). In the second stage, the iterative convex optimization method is used to realize the multibeam pattern synthesis in the sideband. Owing to the introduction of convex optimization, the proposed method could be more efficient than approaches using a global optimization algorithm. The proposed method is capable of realizing pattern synthesis under different DRR constraints and different beam radiation directions. Numerical examples of two beams and four beams patterns of 1000-element time modulated linear array verify the effectiveness of the proposed method.

scholarly journals Research on Pattern Synthesis of Time Modulated Sparse Array Based on Discrete Variable Convex Optimization

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Jing Tan ◽  
Jiawen Hu ◽  
Xikuan Dong ◽  
Hailin Li ◽  
Jianjiang Zhou
Keyword(s):  
Convex Optimization ◽  
Discrete Variable ◽  
Central Frequency ◽  
Pattern Synthesis ◽  
Time Modulation ◽  
Second Stage ◽  
Excitation Time ◽  
Simulation Results ◽  
Two Stages ◽  
Full Utilization

Effective resource utilization is an important problem in the application of array, especially for the new time modulated array. Considering the problem of full utilization of array elements in time modulated array, a sparse optimization algorithm based on discrete variable convex optimization is proposed in this paper. The pattern optimization of equal excitation time modulation array is realized in two stages: In the first stage, the number of working array elements is as low as possible under the condition of suppressing the sidelobe of the central frequency. In the second stage, the sideband is suppressed by iterative convex optimization. The numerical simulation results are compared with other methods to verify the effectiveness of the proposed method in pattern optimization of equal excitation time modulation array. Finally, the optimization performance of the algorithm with different array parameters is verified.

scholarly journals Synthesis of Steered Flat-top Beam Pattern Using Evolutionary Algorithm

2016 ◽  
Vol 5 (3) ◽  
pp. 86 ◽  
Author(s):  
D. Mandal ◽  
K. S. Kola ◽  
J. Tewary ◽  
V. P. Roy ◽  
A. K. Bhattacharjee
Keyword(s):  
Evolutionary Algorithm ◽  
Dynamic Range ◽  
Synthesis Method ◽  
Elevation Angle ◽  
Differential Evolution Algorithm ◽  
Beam Pattern ◽  
Main Beam ◽  
Pattern Synthesis ◽  
Feed Networks ◽  
Flat Top Beam

In this paper a pattern synthesis method based on Evolutionary Algorithm is presented. A Flat-top beam pattern has been generated from a concentric ring array of isotropic elements by finding out the optimum set of elements amplitudes and phases using Differential Evolution algorithm. The said pattern is generated in three predefined azimuth planes instate of a single phi plane and also verified for a range of azimuth plane for the same optimum excitations. The main beam is steered to an elevation angle of 30 degree with lower peak SLL and ripple. Dynamic range ratio (DRR) is also being improved by eliminating the weakly excited array elements, which simplify the design complexity of feed networks.

Synthesis of the Missile Homing System Taking into Account the Dynamic Characteristic of the Measurement Elements

2019 ◽  
Vol 20 (4) ◽  
pp. 251-256 ◽  
Author(s):  
. Do Quang Thong
Keyword(s):  
Dynamic Characteristic ◽  
Dynamic Characteristics ◽  
Dynamic Properties ◽  
Optimization Method ◽  
Frequency Noise ◽  
Negative Effects ◽  
Second Stage ◽  
Basic Functions ◽  
Two Stages

Several various missile homing systems (MHS) have been developed in recent years. However, to the best of our knowledge, these systems do not take into account the dynamic characteristics of the measurement elements (ME). Such existing systems can only work well when the MEs have a small inertia and large damping. Thus in general case, it is necessary to consider the dynamic characteristics of the MEs with the big inertia. In addition, using the MEs with the big inertia, the MHSs is able to remove the high-frequency noise. However, taking into account the dynamic properties of the MEs causes difficulties in determining the transfer function (PF) of the normal acceleration stability system and the synthesis of MHSs. Therefore, in this paper, we propose an effective mathematical model of the missile homing system, which takes into consideration the dynamic characteristics of the MEs. In addition, this model allows synthesizing the high accuracy MHSs, and utilizing the MEs with the inertia equivalent to the inertia of the rudder actuator. To accomplish that, the proposed system is composed of two stages. In the first stage, the MHSs, which do not incorporate the dynamic characteristics of the MEs, is presented in detail. Then, we analyze and estimate the effect of the dynamic characteristics of the MEs on the performance of the MHSs. In the second stage, we propose a novel MHS, which takes into account the dynamic characteristics of the MEs. The proposed system is implemented based on the basic functions in the Control system toolbox in MATLAB, and designed by the parametric optimization method. The simulation results indicate that, our proposed system outperforms the conventional MHSs in term of reducing the negative effects of the dynamic characteristic of the MEs on the quality of the MHS.

scholarly journals Pattern Synthesis of Time-Modulated Sparse Array by an OPM-CVX Algorithm

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Lei Liang ◽  
Yachao Jiang ◽  
Jialing Liu ◽  
Hailin Li ◽  
Jianjiang Zhou
Keyword(s):  
Convex Optimization ◽  
Perturbation Method ◽  
Dynamic Range ◽  
Radiation Power ◽  
Side Lobe ◽  
Switching Function ◽  
Side Lobe Level ◽  
Pattern Synthesis ◽  
Sparse Arrays ◽  
Minimum Number

This paper addresses the constrained multiobjective optimization problem of time-modulated sparse arrays. The synthesis objective is to find an optimal element arrangement and associated excitation strategy of sparse arrays, which realize the balance of radiation power and sideband suppression performance with minimum number of elements, and suppress side lobe level simultaneously. A novel hybrid algorithm based on orthogonal perturbation method and convex optimization (OPM-CVX) for the synthesis of time-modulated sparse antenna array is presented in this paper. In order to satisfy the main lobe beamforming and side lobe suppression of sparse arrays, the proposed method optimizes element positions with minimum array numbers by orthogonal perturbation method and optimizes excitations of array element with dynamic range ratio constraint by convex optimization. Furthermore, a trapezoidal pulse time-modulated switching function is proposed to find the balance of radiation power and sideband suppression performance. The numerical results indicate that the proposed algorithm can be an effective approach for synthesis problems of time-modulated sparse arrays.

Altered Fine Structure of B Lymphocytes Correlated with Defective Terminal Differentiation

1973 ◽  
Vol 31 ◽  
pp. 386-387
Author(s):  
Dale E. Bockman ◽  
L. Y. Frank Wu ◽  
Alexander R. Lawton ◽  
Max D. Cooper
Keyword(s):  
Immune Deficiency ◽  
B Lymphocytes ◽  
Plasma Cells ◽  
Present Report ◽  
Specific Antigen ◽  
Terminal Differentiation ◽  
Second Stage ◽  
Two Stages ◽  
Deficiency Diseases ◽  
Cell Line Generation

B-lymphocytes normally synthesize small amounts of immunoglobulin, some of which is incorporated into the cell membrane where it serves as receptor of antigen. These cells, on contact with specific antigen, proliferate and differentiate to plasma cells which synthesize and secrete large quantities of immunoglobulin. The two stages of differentiation of this cell line (generation of B-lymphocytes and antigen-driven maturation to plasma cells) are clearly separable during ontogeny and in some immune deficiency diseases. The present report describes morphologic aberrations of B-lymphocytes in two diseases in which second stage differentiation is defective.

Distributed Entropy Energy-Efficient Clustering algorithm for cluster head selection (DEEEC)

2020 ◽  
Vol 39 (6) ◽  
pp. 8139-8147
Author(s):  
Ranganathan Arun ◽  
Rangaswamy Balamurugan
Keyword(s):  
Energy Efficient ◽  
Clustering Algorithm ◽  
Cluster Head ◽  
Residual Energy ◽  
Energy Utilization ◽  
Sensor Nodes ◽  
Second Stage ◽  
Energy Efficient Clustering ◽  
Two Stages ◽  
Ch Selection

In Wireless Sensor Networks (WSN) the energy of Sensor nodes is not certainly sufficient. In order to optimize the endurance of WSN, it is essential to minimize the utilization of energy. Head of group or Cluster Head (CH) is an eminent method to develop the endurance of WSN that aggregates the WSN with higher energy. CH for intra-cluster and inter-cluster communication becomes dependent. For complete, in WSN, the Energy level of CH extends its life of cluster. While evolving cluster algorithms, the complicated job is to identify the energy utilization amount of heterogeneous WSNs. Based on Chaotic Firefly Algorithm CH (CFACH) selection, the formulated work is named “Novel Distributed Entropy Energy-Efficient Clustering Algorithm”, in short, DEEEC for HWSNs. The formulated DEEEC Algorithm, which is a CH, has two main stages. In the first stage, the identification of temporary CHs along with its entropy value is found using the correlative measure of residual and original energy. Along with this, in the clustering algorithm, the rotating epoch and its entropy value must be predicted automatically by its sensor nodes. In the second stage, if any member in the cluster having larger residual energy, shall modify the temporary CHs in the direction of the deciding set. The target of the nodes with large energy has the probability to be CHs which is determined by the above two stages meant for CH selection. The MATLAB is required to simulate the DEEEC Algorithm. The simulated results of the formulated DEEEC Algorithm produce good results with respect to the energy and increased lifetime when it is correlated with the current traditional clustering protocols being used in the Heterogeneous WSNs.

Analisis Kebutuhan Petunjuk Praktikum Berbasis Keterampilan Proses Sains untuk Mencapai Kemampuan Merancang Eksperimen

2019 ◽  
Vol 2 (2) ◽  
Author(s):  
Fitriah Khoirunnisa ◽  
Friska Septiani Silitonga ◽  
Veri Firmansyah
Keyword(s):  
Core Competence ◽  
Process Skills ◽  
Learning Materials ◽  
Science Process Skills ◽  
Second Stage ◽  
The Core ◽  
The Core Competence ◽  
Two Stages ◽  
Practical Instruction ◽  
Design Experiments

Penelitian ini bertujuan menganalisis kebutuhan petunjuk praktikum berbasis Keterampilan Proses Sains (KPS) untuk mencapai kemampuan merancang eksperimen pada materi kalor reaksi kalorimetri. Penelitian dilakukan terhadap peserta didik kelas XI SMA Negeri 2 Kota Tanjungpinang. Variabel penelitian mencakup analisis kebutuhan bahan ajar dan analisis kesesuaian Kompetensi Inti (KI) dan Kompetensi Dasar (KD). Jenis penelitian yang dilakukan adalah penelitian deskriptif kualitatif. Tahapan pertama dalam penelitian ini adalah menganalisis kebutuhan bahan ajar dengan cara membandingkan dua petunjuk praktikum yang selama ini telah digunakan di sekolah tersebut, ditinjau dari aspek struktur format penulisan, aspek kreativitas, dan aspek keterampilan proses sains yang terdapat dalam petunjuk praktikum. Sehingga didapatkan kesimpulan bahwa petunjuk praktikum yang selama ini digunakan tidak memberikan kesempatan kepada peserta didiknya untuk merancang eksperimen yang telah ditentukan. Tahapan kedua yaitu menganalisis kesesuaian kompetensi inti dan kompetensi dasar, yang bertujuan untuk menentukan indikator pencapaian kompetensi (IPK) yang akan menjadi acuan dalam mengembangkan petunjuk praktikum berbasis keterampilan proses sains. Dari kedua tahapan yang telah dilakukan maka dapat disimpulkan bahwa peserta didik memerlukan petunjuk praktikum yang mampu mengonstruksi pikiran dan mengaktifkan kinerja mereka, sehingga pendekatan Keterampilan Proses Sains menjadi pilihan dalam mengembangkan petunjuk praktikum yang sesuai dengan karakteristik kurikulum 2013.   This research aims to analyze the needs of Science Process Skills based Practical Instruction to achieve the ability to design experiments on the calor of reaction. This research was done to the students of class XI SMA Negeri 2 Tanjungpinang City. Research Variable includes the analysis of the needs of the learning materials and analysis of the suitability of the Core Competence (KI) and Basic Competence (KD). The type of research conducted is descriptive qualitative research. The first stages in this research is to analyze the needs of learning materials by comparing two practical instructions that had been implementing in the school, from the aspects of the structure of writing format, creativity, and science process skills embedded in practical instructions. The conclusion of this research that current practical instructions does not give an opportunity to the participants to design determined experiments. The second stage, namely analyzing the suitability of core competence and basic competence, which aims to determine the indicators of achievement of the competencies (GPA) which will be a reference in developing process skills-based teaching instructions science. Of the two stages that has been done then it can be concluded that learners need practical instructions to construct  thinking and and their performance, so the Science Process Skills approach is an option in developing practical instruction suitable for the characteristics of the curriculum of 2013.

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