Research on the Development Efficiency of Family Farm based on DEA Model : A Case Study

Ningbo Cui,HeXiang Sang,Xingye Yu 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.5

In this paper, through the actual investigation of the production and operation in the main grain producing areas, the authors collected data from 89 farms in Northeast China. This paper first describes the individual characteristics of the family farm operators, the size of the land and the circulation of the farm, the situation of the farm to obtain funds and information services. Then we estimate the development efficiency based on the DEA model, by using the survey data. The results show that family farm business process is lack of new agricultural technologies; family farmers’ management ability is weak, the factors of production inputs such as unreasonable causes share of the family farm in Northeast DEA efficiency is low. In order to develop the efficiency of the family farm, government should put forward and optimize the land circulation system, pay attention to the quality of the family farmers, and improve the agricultural technology extension system, optimize the allocation of production factors.

Synthesis of large diameter plat-like Ca3Co4O9 particle by molten salt method

Ningbo Feng,Yingrong Jin,Sujun Guan,Yi He,Liang Hao,Yun Lu 한양대학교 세라믹연구소 2016 Journal of Ceramic Processing Research Vol.17 No.10

The Ca3Co4O9 was synthesized by molten salt method using CoO, CaCO3 and CaCl2 as stating materials. The thermal behaviorwas investigated by directly measuring and comparing the temperatures of the mixture and reference material simultaneously. The obtained compounds were characterized by XRD, SEM and EDS. The results showed that CaCO3 and CaCl2 form amolten salt solution at about 628 oC. The highly c axis oriented plat-like Ca3Co4O9 particles were obtained at 800 oC for 4 hrsand the Ca3Co4O9 particles reaches about 300 µm in diameter and 20 µm in thickness. The template formation processdominates the nucleation of Ca3Co4O9 and the shape transformation to plat-like shape has happened in the growth ofCa3Co4O9 nuclei.

A numerical study on ice failure process and ice-ship interactions by Smoothed Particle Hydrodynamics

Ningbo Zhang,Xing Zheng,Qingwei Ma,Zhenhong Hu 대한조선학회 2019 International Journal of Naval Architecture and Oc Vol.11 No.2

In this paper, a Smoothed Particle Hydrodynamics (SPH) method is extended to simulate the ice failure process and ice-ship interactions. The softening elastoplastic model integrating Drucker-Prager yield criterion is embedded into the SPH method to simulate the failure progress of ice. To verify the accuracy of the proposed SPH method, two benchmarks are presented, which include the elastic vibration of a cantilever beam and three-point bending failure of the ice beam. The good agreement between the obtained numerical results and experimental data indicates that the presented SPH method can give the reliable and accurate results for simulating the ice failure progress. On this basis, the extended SPH method is employed to simulate level ice interacting with sloping structure and three-dimensional iceship interaction in level ice, and the numerical data is validated through comparing with experimental results of a 1:20 scaled Araon icebreaker model. It is shown the proposed SPH model can satisfactorily predict the ice breaking process and ice breaking resistance on ships in ice-ship interaction.

Depoling of porous Pb0.99(Zr0.95Ti0.05)0.98Nb0.02O3 ferroelectric ceramics under shock wave load

Ningbo Feng,Hengchang Nie,Xuefeng Chen,Genshui Wang,Xianlin Dong,Hongliang He 한국물리학회 2010 Current Applied Physics Vol.10 No.6

Poled Pb0.99(Zr0.95Ti0.05)0.98Nb0.02O3 ferroelectric ceramics in different porosity depoled under shock wave load. Porosity and material dielectric characteristic effects on the depoling current evolution were discussed. The results showed that under open circuit condition, the dielectric constant of all samples exhibited obvious increase, but as the porosity increased, the dielectric constant decreased. As a result of lower dielectric constant of porous samples during depoling process, the charge-releasing rate is faster than that of dense sample.

A numerical study on ice failure process and ice-ship interactions by Smoothed Particle Hydrodynamics

Zhang, Ningbo,Zheng, Xing,Ma, Qingwei,Hu, Zhenhong The Society of Naval Architects of Korea 2019 International Journal of Naval Architecture and Oc Vol.11 No.2

In this paper, a Smoothed Particle Hydrodynamics (SPH) method is extended to simulate the ice failure process and ice-ship interactions. The softening elastoplastic model integrating Drucker-Prager yield criterion is embedded into the SPH method to simulate the failure progress of ice. To verify the accuracy of the proposed SPH method, two benchmarks are presented, which include the elastic vibration of a cantilever beam and three-point bending failure of the ice beam. The good agreement between the obtained numerical results and experimental data indicates that the presented SPH method can give the reliable and accurate results for simulating the ice failure progress. On this basis, the extended SPH method is employed to simulate level ice interacting with sloping structure and three-dimensional ice-ship interaction in level ice, and the numerical data is validated through comparing with experimental results of a 1:20 scaled Araon icebreaker model. It is shown the proposed SPH model can satisfactorily predict the ice breaking process and ice breaking resistance on ships in ice-ship interaction.

Adaptive Fault-tolerant Control for Trajectory Tracking and Rectification of Directional Drilling

Chi Zhang,Wei Zou,Ningbo Cheng,Junshan Gao 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.1

Motivated by the increasing demands on complex borehole trajectories in oil and gas directional drilling, an adaptive fault-tolerant control (AFTC) method for drilling trajectory tracking and rectification of rotary steerable system (RSS) is proposed by adopting actor-critic reinforcement learning (RL) and integral sliding mode control (ISMC) in the presence of system uncertainties and fault signals. Considering a discrete delay differential equation (DDE) with distance delays, uncertainties and fault signals, first we design an online learning framework via actor-critic RL and radial basis function neural network (RBFNN) in order to make drill bit can track pre-designed trajectory accurately and smoothly. Then in order to handle the fault signals problem, we utilize ISMC to eliminate it as weak as possible and rectify drilling trajectory which may derivate original direction caused by it. The system stability and convergence have been analyzed to ensure uniformly ultimately boundedness of tracking errors and fault-tolerant control signals. The proposed method would have wide application potentials in realizing the trajectory tracking and rectification with automatic operations of directional drilling. The effectiveness and accuracy of it are validated by simulation results with ramp and sine input signals.

Cooperative and Competitive Effect in Heterogeneous Networks of Healthcare System

( Xiaoshuang Liu ),( Guixia Kang ),( Ningbo Zhang ),( Yanyan Guo ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.11

Different network provides different service. To maximize the profit, heterogeneous networks form a whole, which may either compete or cooperate with each other. In this paper, the healthcare monitor network architecture is introduced to build the competitive and cooperative mechanisms of heterogeneous networks which contain three networks, namely, cellular network, WLAN and WMAN. This paper considers the natural growth rate of the network with competitive and cooperative effects. Then, the stability of the proposed model and its equilibrium points are analyzed by the ordinary differential principle. Finally, simulation results show that the natural growth rate cannot increase the profit of the network, but effective cooperative among heterogeneous networks can increase the profit of each network, and competitive may decrease the profit of each network.

Percolation Theory-Based Exposure-Path Prevention for 3D-Wireless Sensor Networks Coverage

( Xiaoshuang Liu ),( Guixia Kang ),( Ningbo Zhang ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.1

Different from the existing works on coverage problems in wireless sensor networks (WSNs), this paper considers the exposure-path prevention problem by using the percolation theory in three dimensional (3D) WSNs, which can be implemented in intruder detecting applications. In this paper, to avoid the loose bounds of critical density, a bond percolation-based scheme is proposed to put the exposure-path problem into a 3D uniform lattice. Within this scheme, the tighter bonds of critical density for omnidirectional and directional sensor networks under random sensor deployment―a 3D Poisson process are derived. Extensive simulation results show that our scheme generates tighter bounds of critical density with no exposure path in 3D WSNs.

Performance Analysis of Three-Phase Phase-Locked Loops for Distorted and Unbalanced Grids

Li, Kai,Bo, An,Zheng, Hong,Sun, Ningbo The Korean Institute of Power Electronics 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.1

This paper studies the performances of five typical Phase-locked Loops (PLLs) for distorted and unbalanced grid, which are the Decoupled Double Synchronous Reference Frame PLL (DDSRF-PLL), Double Second-Order Generalized Integrator PLL (DSOGI-PLL), Double Second-Order Generalized Integrator Frequency-Lock Loop (DSOGI-FLL), Double Inverse Park Transformation PLL (DIPT-PLL) and Complex Coefficient Filter based PLL (CCF-PLL). Firstly, the principles of each method are meticulously analyzed and their unified small-signal models are proposed to reveal their interior relations and design control parameters. Then the performances are compared by simulations and experiments to investigate their dynamic and steady-state performances under the conditions of a grid voltage with a negative sequence component, a voltage drop and a frequency step. Finally, the merits and drawbacks of each PLL are given. The compared results provide a guide for the application of current control, low voltage ride through (LVRT), and unintentional islanding detection.

Performance Analysis of Three-Phase Phase-Locked Loops for Distorted and Unbalanced Grids

Kai Li,An Bo,Hong Zheng,Ningbo Sun 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.1

This paper studies the performances of five typical Phase-locked Loops (PLLs) for distorted and unbalanced grid, which are the Decoupled Double Synchronous Reference Frame PLL (DDSRF-PLL), Double Second-Order Generalized Integrator PLL (DSOGI-PLL), Double Second-Order Generalized Integrator Frequency-Lock Loop (DSOGI-FLL), Double Inverse Park Transformation PLL (DIPT-PLL) and Complex Coefficient Filter based PLL (CCF-PLL). Firstly, the principles of each method are meticulously analyzed and their unified small-signal models are proposed to reveal their interior relations and design control parameters. Then the performances are compared by simulations and experiments to investigate their dynamic and steady-state performances under the conditions of a grid voltage with a negative sequence component, a voltage drop and a frequency step. Finally, the merits and drawbacks of each PLL are given. The compared results provide a guide for the application of current control, low voltage ride through (LVRT), and unintentional islanding detection.