http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Non-obstructive particle damping using principles of gas-solid flows
Xiaofei Lei,Chengjun Wu 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.3
Non-obstructive particle damping is a type of nonlinear damping related to the velocity amplitude of a vibrating structure. Many scholars have spent considerable time researching the damping and energy dissipation mechanism due to interparticle collision and friction, and they achieved corresponding results by using the principles of gas-solid flows and discrete element method. However, the damping mechanism due to kinetic dissipation between particles and gas has been entirely ignored. In this paper, a mathematical evaluation of the damping mechanisms due to kinetic dissipation is performed by using the principles of gas-solid flows. For systematic research into the application of non-obstructive particle damping technology in engineering practice, the improved model is perfectly embedded into finite element software by using co-simulation technology, in which MATLAB invokes a COMSOL file and controls the calculation process. A frequency analysis of the experiment verifies that the prediction accuracy of the improved model is obviously increased. Moreover, energy dissipation was explored by using the principles of gas-solid flows. Results indicate that particle damping technology can effectively control the structure vibration at a higher-order frequency. However, the energy dissipation mechanism takes effect at a lowerorder frequency.
( Xiaofei Di ),( Ke Xiong ),( Yu Zhang ),( Zhengding Qiu ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.1
This paper investigates the simultaneous wireless information and power transfer (SWIPT) for two-hop orthogonal frequency division multiplexing (OFDM) decode-and-forward (DF) relay network, where a relay harvests energy from radio frequency signals transmitted by a source and then uses the harvested energy to assist information transmission from the source to its destination. The power splitting receiver is considered at the relay. To explore the performance limit of such a SWIPT-enabled system, a resource allocation (RA) optimization problem is formulated to maximize the achievable information rate of the system, where the power allocation, the subcarrier pairing and the power splitting factor are jointly optimized. As the problem is non-convex and there is no known solution method, we first decompose it into two separate subproblems and then design an efficient RA algorithm. Simulation results demonstrate that our proposed algorithm can achieve the maximum achievable rate of the system and also show that to achieve a better system performance, the relay node should be deployed near the source in the SWIPT-enabled two-hop OFDM DF relay system, which is very different from that in conventional non-SWIPT system where the relay should be deployed at the midpoint of the line between the source and the destination.
Kano Model Analysis Required in APP Interactive Design based on Mobile User Experience
Xiaofei Li,Yue You 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.11
The user experience in APP interactive designdraws more and more attention in the APP market where the user population expands continuously and the competition becomes increasingly intense, butcurrent studies mostly focus on the user website experience. This paper is intended to classify and study user needs in APP interactive design based on Kano model and Better-Worse coefficient, and gain Kano two-dimensional attribute classification of user needsin the design. In addition, it carries out analysis on these needs based on the better-worse coefficient.
Xiaofei Sun,Kangning Wang,Lu Lin 한국통계학회 2018 Journal of the Korean Statistical Society Vol.47 No.1
Partial linear varying coefficient models are often used in real data analysis for a good balance between flexibility and parsimony. In this paper, we propose a robust adaptive model selection method based on the rank regression, which can do simultaneous coefficient estimation and three types of selections, i.e., varying and constant effects selection, relevant variable selection. The new method has superiority in robustness and efficiency by inheriting the advantage of the rank regression approach. Furthermore, consistency in the three types of selections and oracle property in estimation are established as well. Simulation studies also confirm our method.
A Simple and Fast Action Recognition Method Based on AdaBoost Algorithm
Xiaofei Ji,Lu Zhou,Ningli Qin,Yibo Li 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.8
A novel feature representation method based on AdaBoost algorithm is put forward for action recognition in this paper. The method can not only adequately describe action in complex scenarios, but also select the most discriminative sample subset from a large amount of raw features of training data. So it can realize a double result, that is, reduce the recognition computational complexity and achieve a good recognition accuracy. The pyramid histogram of oriented gradient feature (PHOG) descriptor is utilized to represent raw feature data. In order to select most discriminative samples subset, AdaBoost algorithm is used to extract the raw feature data. The nearest neighbor classifier algorithm is utilized to test the proposed method on the UCF Sports database. Experiment results show that the method not only achieve the better recognition rate but also greatly improve the speed of recognition.
Xiaofei Wang,Shaobin Hu,Enyuan Wang 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.4
The novel dry ice powder static blasting rock breaking lacked working standards, especially for the vibration safety assessment of the construction site for the protection of the building structure, in comparison with the traditional drill and blast method which had a proven operational process and safety specifications. The Sadovsky vibration velocity prediction formula could only predict the vibration velocity and was project specific. Oscillation parameters that needed to be considered in the vibration safety assessment, such as the dominant frequency of vibration, could not be obtained through empirical formulas. Using the five parameters of hole depth, blast center distance, dry ice powder mass and rock classification as the main influencing factors, BP and RBF neural network models were constructed by Matlab software to predict the peak vibration velocity, main frequency and maximum displacement of dry ice powder blasting. Projection results revealed that it is structurally simpler than the BP neural network and that the RBF was more accurate in predicting the target than the BP network. The results of the study had significant implications for the safe application of the new technology, and more samples of field data need to be obtained in the future, along with the use of more advanced predictive modelling.
Xiaofei Zhou,Jiawei Wan,Yefeng Liu,Di Liu,Hong Wang,Xiaoyong Lai,Yanzhao Zou,Guo Lin,Jian Chen 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.9
A cooperative assembly route has been developed, by which silver nanoparticles with controlled sizes are incorporated into the channels of ordered cubic mesoporous silica (KIT-6) with different pore sizes (4.3–6.4 nm). The samples were characterized by XRD, TEM, FT-IR, UV-Vis and N2 physisorption. The pore wall of mesoporous silica can efficiently confine the growth of silver nanoparticles within the channels and their average sizes decreased with the pore size reduction of KIT-6. Catalytic activities of the resultant Ag/KIT-6-x (x stands for hydrothermal temperature) composite for reducing harmful organic dye Rhodamine B (Rh B) by sodium borohydride (NaBH4) were investigated. All the Ag/KIT-6 composite samples show great catalytic activities, among which Ag/KIT-6-80 with higher loading and smaller size of Ag nanoparticles exhibits higher catalytic activity than those of Ag/KIT-6-60 and Ag/KIT-6-100.
Research on Electromagnetic Effect of Irradiation on Silicon via Interconnects
Xiaofei Xu,Denghua Li 한국전기전자재료학회 2020 Transactions on Electrical and Electronic Material Vol.21 No.3
The paper was studied the damage effect mechanism of proton radiation on metallic interconnect, where the metal electron migration was caused by space ion irradiation. A physical transfer model of via was constructed, where the equivalent distribution parameters circuit structure was extracted. The parameters of the electromagnetic eff ect of copper via interconnects were calculated under diff erent irradiation dose rates. The study showed the result of the influence on via length of the eff ective transmission signal, the infl uence of radiation on the characteristic impedance, and the effect of radiation on the failure of via, which could provide a theoretical instruction to enhance the anti-TID ability.