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UWB Bi-directional Bow-tie Antenna Loaded by Rings
Lin Peng,Kai Sun,Ji-yang Xie,Yu-jie Qiu,Xing Jiang 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.1
Performances of bow-tie antennae can be improved by loading a ring. Specially, the distorted radiation patterns of the reference bow-tie antenna (RBA) at high frequencies become less distorted when a ring is added. That is due to the disciplined current flows trained by the ring. Furthermore, when more rings are loaded, which act as reflectors, higher directivities are obtained and, patterns become bi-directional. Antennae with no ring (RBA), one ring, two rings (three cases), three rings, and four rings are investigated. Research find that loading more rings means better directivity. The directivity of the RBA varies from 2.29 dB to 3.66 dB for the frequency band from 2.5 to 7.5 GHz while the directivity for the four-ring-loaded case varies from 4.27 dB to 7.61 dB in that frequency band.
Linpeng Wang,Jin Zhu,Junhong Park 제어·로봇·시스템학회 2012 International Journal of Control, Automation, and Vol.10 No.5
This paper is concerned with the model following problem of Markovian jump linear systems (MJLSs), which suffer from stochastic uncertainties and actuator saturation. By applying a probabilistic approach based on particles, a sequence of control inputs is designed to guarantee that the model following error remains within a desired region in a certain probability, as well as the control cost is optimal. Motivated by this, the stochastic control problem is represented by chance constrained pro-gramming, and approximated as a determinate optimization one, which is solved by mixed integer li-near programming (MILP). Furthermore, an improved particle control approach is proposed to reduce the computation complexity. The effectiveness of this improved approach is demonstrated by an example along with complexity comparison.
Experimental Study on Load-Bearing Capacities of Frame-Type Scaff olds Used in Precast Construction
Jui-LinPeng,Pao-Li Wang,Siu-Lai Chan,Po-Kai Wu 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.2
In precast construction, because the precast beams are broader and the frame-type steel scaffolds need to bear more weight, such as that of the precast slabs and precast beams, the dimensions and load-bearing capacities of the frame-type steel scaffolds are different from those of traditional door-type steel scaffolds. The results of this study show that based on the load-bearing capacities of the five different combined setups of frame-type steel scaffolds used in this study, the horizontal members of the square-type and rectangle-type steel scaffolds are able to enhance the load-bearing capacities of the combined setups of the frame-type steel scaffolds. Therefore, when adopting combined setups of frame-type steel scaffolds, it is advisable to refrain from using only door-type steel scaffolds on construction sites. The ability of jack bases to enhance the load-bearing capacities of frame-type steel scaffolds is not significant. Under the condition of an eccentric load located at one-third of both the x-axis and y-axis, the load-bearing capacity of the frame-type steel scaffolds reduces to 60% of that when no eccentric load is involved. When a lateral force is applied, the critical load of frame-type steel scaffolds decreases with increasing lateral forces.
Black box-assisted fine-grained hierarchical access control scheme for epidemiological survey data
Xueyan Liu,Ruirui Sun,Linpeng Li,Wenjing Li,Tao Liu 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.9
Epidemiological survey is an important means for the prevention and control of infectious diseases. Due to the particularity of the epidemic survey, 1) epidemiological survey in epidemic prevention and control has a wide range of people involved, a large number of data collected, strong requirements for information disclosure and high timeliness of data processing; 2) the epidemiological survey data need to be disclosed at different institutions and the use of data has different permission requirements. As a result, it easily causes personal privacy disclosure. Therefore, traditional access control technologies are unsuitable for the privacy protection of epidemiological survey data. In view of these situations, we propose a black box-assisted fine-grained hierarchical access control scheme for epidemiological survey data. Firstly, a black box-assisted multi-attribute authority management mechanism without a trusted center is established to avoid authority deception. Meanwhile, the establishment of a master key-free system not only reduces the storage load but also prevents the risk of master key disclosure. Secondly, a sensitivity classification method is proposed according to the confidentiality degree of the institution to which the data belong and the importance of the data properties to set fine-grained access permission. Thirdly, a hierarchical authorization algorithm combined with data sensitivity and hierarchical attribute-based encryption (ABE) technology is proposed to achieve hierarchical access control of epidemiological survey data. Efficiency analysis and experiments show that the scheme meets the security requirements of privacy protection and key management in epidemiological survey.
Hu, Xuefeng,Zhang, Meng,Li, Yongchao,Li, Linpeng,Wu, Guiyang The Korean Institute of Power Electronics 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.3
This paper presents a ripple-free input current modified interleaved boost converter for high step-up applications. By integrating dual coupled inductors and voltage multiplier techniques, the proposed converter can reach a high step-up gain without an extremely high turn-ON period. In addition, a very small auxiliary inductor employed in series to the input dc source makes the input current ripple theoretically decreased to zero, which simplifies the design of the electromagnetic interference (EMI) filter. In addition, the voltage stresses on the semiconductor devices of the proposed converter are efficiently reduced, which makes high performance MOSFETs with low voltage rated and low resistance $r_{DS}$(ON) available to reduce the cost and conduction loss. The operating principles and steady-state analyses of the proposed converter are introduced in detail. Finally, a prototype circuit rated at 400W with a 42-50V input voltage and a 400V output voltage is built and tested to verify the effectiveness of theoretical analysis. Experimental results show that an efficiency of 95.3% can be achieved.
Xuefeng Hu,Meng Zhang,Yongchao Li,Linpeng Li,Guiyang Wu 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.3
This paper presents a ripple-free input current modified interleaved boost converter for high step-up applications. By integrating dual coupled inductors and voltage multiplier techniques, the proposed converter can reach a high step-up gain without an extremely high turn-ON period. In addition, a very small auxiliary inductor employed in series to the input dc source makes the input current ripple theoretically decreased to zero, which simplifies the design of the electromagnetic interference (EMI) filter. In addition, the voltage stresses on the semiconductor devices of the proposed converter are efficiently reduced, which makes high performance MOSFETs with low voltage rated and low resistance rDS(ON) available to reduce the cost and conduction loss. The operating principles and steady-state analyses of the proposed converter are introduced in detail. Finally, a prototype circuit rated at 400W with a 42-50V input voltage and a 400V output voltage is built and tested to verify the effectiveness of theoretical analysis. Experimental results show that an efficiency of 95.3% can be achieved.