Performance Analysis of Energy-Efficient Secure Transmission for Wireless Powered Cooperative Networks with Imperfect CSI

Yajun Zhang,Jun Wu,Bing Wang,Hongkai Wang,Xiaohui Shang 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.9

The paper focuses on investigating secure transmission in wireless powered communication networks (WPCN) that involve multiple energy-constrained relays and one energy-constrained source. The energy is harvested from a power beacon (PB) while operating in the presence of a passive eavesdropper. The study primarily aims to achieve energy-efficient secure communications by examining the impact of channel estimation on the secrecy performance of WPCN under both perfect and imperfect CSI scenarios. To obtain practical insights on improving security and energy efficiency, we propose closed-form expressions for secrecy outage probability (SOP) under the linear energy harvesting (LEH) model of WPCN. Furthermore, we suggest a search method to optimize the secure energy efficiency (SEE) with limited power from PB. The research emphasizes the significance of channel estimation in maintaining the desired performance levels in WPCN in real-world applications. The theoretical results are validated through simulations to ensure their accuracy and reliability.

A novel story on rock slope reliability, by an initiative model that incorporated the harmony of damage, probability and fuzziness

Wang, Yajun Techno-Press 2017 Geomechanics & engineering Vol.12 No.2

This study aimed to realize the creation of fuzzy stochastic damage to describe reliability more essentially with the analysis of harmony of damage conception, probability and fuzzy degree of membership in interval [0,1]. Two kinds of fuzzy behaviors of damage development were deduced. Fuzzy stochastic damage models were established based on the fuzzy memberships functional and equivalent normalization theory. Fuzzy stochastic damage finite element method was developed as the approach to reliability simulation. The three-dimensional fuzzy stochastic damage mechanical behaviors of Jianshan mine slope were analyzed and examined based on this approach. The comprehensive results, including the displacement, stress, damage and their stochastic characteristics, indicate consistently that the failure foci of Jianshan mine slope are the slope-cutting areas where, with the maximal failure probability 40%, the hazardous Domino effects will motivate the neighboring rock bodies' sliding activities.

Distributed Power and Rate Control for Cognitive Radio Networks

Wang, Wei,Wang, Wenbo,Zhu, Yajun,Peng, Tao The Korea Institute of Information and Commucation 2009 Journal of communications and networks Vol.11 No.2

In this paper, a distributed power and end-to-end rate control algorithm is proposed in the presence of licensed users. By Lagrangian duality theory, the optimal power and rate control solution is given for the unlicensed users while satisfying the interference temperature limits to licensed users. It is obtained that transmitting with either 0 or the maximum node power is the optimal scheme. The synchronous and asynchronous distributed algorithms are proposed to be implemented at the nodes and links. The convergence of the proposed algorithms are proved. Finally, further discussion on the utility-based fairness is provided for the proposed algorithms. Numerical results show that the proposed algorithm can limit the interference to licensed user under a predefined threshold.

Distributed Power and Rate Control for Cognitive Radio Networks

Wei Wang,Wenbo Wang,Tao Peng,Yajun Zhu 한국통신학회 2009 Journal of communications and networks Vol.11 No.2

In this paper, a distributed power and end-to-end rate control algorithm is proposed in the presence of licensed users. By Lagrangian duality theory, the optimal power and rate control solution is given for the unlicensed users while satisfying the interference temperature limits to licensed users. It is obtained that transmitting with either 0 or the maximum node power is the optimal scheme. The synchronous and asynchronous distributed algorithms are proposed to be implemented at the nodes and links. The convergence of the proposed algorithms are proved. Finally, further discussion on the utility-based fairness is provided for the proposed algorithms. Numerical results show that the proposed algorithm can limit the interference to licensed user under a predefined threshold.

Ontology-Based Exchange of Product Data Semantics between CAD and CAE

Qinyi Ma,Yajun Wang,Yan Lv,Xin Jin,Maojun Zhou 보안공학연구지원센터 2014 International Journal of Multimedia and Ubiquitous Vol.9 No.12

The interoperation of various applications will need a representation that goes beyond the traditional geometry-based one, which is inadequate for capturing semantic information. This paper proposes an approach to annotate the CAD models based on ontology with the aim of making the design intent understood by computer and applied in engineering analysis, such as FEA. The paper presents the design domain ontology and FEA domain ontology, and applies feature technologies and the semantic Web to complete annotation. Semantic markup can embed the engineering semantic information such as product function, and design principle into the CAD geometry data through annotating, it makes the analyzers reuse design ideas quickly and conveniently to increase efficiency. The semantic file is proposed to support an exchange of product data semantics between CAD and CAE. The main idea of the approach is presented and key technologies are elaborated, including the creation of the FEA solution template, and the matching algorithm between semantic markup file and FEA template file. Finally, the feasibility and effectiveness of the approach is empirically validated by a case study.

A 2-40 Gb/s PAM4/NRZ Dual-mode Wireline Transmitter with 4:1 MUX in 65-nm CMOS

Fangxu Lv,Xuqiang Zheng,Feng Zhao,Jianye Wang,Ziqiang Wang,Shuai Yuan,Yajun He,Chun Zhang,Zhihua Wang 대한전자공학회 2018 Journal of semiconductor technology and science Vol.18 No.2

This paper presents a 2-40 Gb/s dual-mode wireline transmitter supporting the four-level pulse amplitude modulation (PAM4) and non-return-tozero (NRZ) modulation with a multiplexer (MUX)-based two-tap feed-forward equalizer (FFE). An edgeacceleration technique is proposed for the 4:1 MUX to increase the bandwidth. By utilizing a dedicated cascode current source, the output swing can achieve 900 mV with a level deviation of only 0.12% for PAM4. Fabricated in a 65-nm CMOS process, the transmitter consumes 117 mW and 89 mW at 40 Gb/s in PAM4 and NRZ at 1.2 V supply.

Effect of La2O3 on the microstructure and electrical properties of ZnO linear resistors

Yajun Fu,Jiajia Lu,Jin Wang,Liangfeng Li 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.4

ZnO-MgO-Al2O3-TiO2-Y2O3 linear resistors with different amount of La2O3 were successfully prepared by the conventionalsolid-state sintering method. The crystalline phase composition, microstructure, and electrical properties of La2O3 doped ZnOlinear resistors were investigated. The results show that La2O3 influences the lattice of ZnO and generates La-rich phase atthe grain boundaries, which improves the dense density of ZnO linear resistors. The addition of La2O3 further affect theelectrical properties of ZnO linear resistors, such as the temperature stability. The sample with 0.5 wt.% La2O3 show excellentelectrical performance with an resistance-temperature coefficient of 0.21×10-3/°C and an nonlinear coefficient of 1.05.

Deposition and evaluation of MoNx films deposited by magnetron sputtering

Yajun Ma,Shenghua Li,Yuansheng Jin,Guoshun Pan,Yucong Wang,Simon C. Tung 한국트라이볼로지학회 2002 한국트라이볼로지학회 학술대회 Vol.2002 No.10

Molybdenum Nitrided (MoNx) films were deposited by DC planar magnetron sputtering. Silicon wafers and real nitrided stainless steel piston rings are employed as substrates. 12 different combinations of nitrogen and argon partial pressure, from 1:7 to 7:1, were applied to deposit MoNx films. X-ray diffraction (XRD) was used to determine the phase structures of films. When nitrogen vs. argon partial pressure is 1:7, the film is mainly MO₂N phase. With increase of nitrogen partial pressure, MoN phase emerges, but MO₂N phase still exists. Composition analysis with atomic emission spectrometry (AES) also agreed with this. The films have very high nanohardness (max 2400Hv) and good adhesion to the substrates.

Optimization Strategy on Conformal Polishing of Precision Optics using Bonnet Tool

Ri Pan,Yajun Zhang,Jianbiao Ding,Changqing Huang,Zhenzhong Wang 한국정밀공학회 2016 International Journal of Precision Engineering and Vol.17 No.3

For the purpose of optimizing the polishing process of ultra-precision optics, the optimal motion for bonnet tool used in conformal polishing (CP) is investigated. Firstly, the removal mechanism in CP was studied and analyzed, based on which the conformal polishing conditions (CPC) and the conclusion that sub-steps precession (S-s-P) is the optimal motion were obtained; After that, corresponding simulations and experiments were conducted, and the results revealed that (1) the ability for CP of continuous precession (Con-P) was not stable, and only when the round distance S and the total polishing length are sufficiently tiny and large, meanwhile, S / vfx = 2*π/ωA is satisfied, the conformal polishing performance of Con-P is good. However, these requirements would limit its application in engineering; (2) Both the incline polishing (IP) and S-s-P models have good performance on CP, and their abilities for CP were not affected by the feeding speed. However, since the texture of the polished area of IP is not so good as S-s- P, the later is the most favourite model in CP. All the results have proven the correctness of the CPC and the theoretical conclusion, which is useful for the engineering application of S-s-P model of bonnet tool.

Optimization Strategy on Conformal Polishing of Precision Optics using Bonnet Tool

Ri Pan,Yajun Zhang,Jianbiao Ding,Changqing Huang,Zhenzhong Wang 한국정밀공학회 2016 International Journal of Precision Engineering and Vol.17 No.5

For the purpose of optimizing the polishing process of ultra-precision optics, the optimal motion for bonnet tool used in conformal polishing (CP) is investigated. Firstly, the removal mechanism in CP was studied and analyzed, based on which the conformal polishing conditions (CPC) and the conclusion that sub-steps precession (S-s-P) is the optimal motion were obtained; After that, corresponding simulations and experiments were conducted, and the results revealed that (1) the ability for CP of continuous precession (Con-P) was not stable, and only when the round distance S and the total polishing length are sufficiently tiny and large, meanwhile, S / vfx = 2*π/ωA is satisfied, the conformal polishing performance of Con-P is good. However, these requirements would limit its application in engineering; (2) Both the incline polishing (IP) and S-s-P models have good performance on CP, and their abilities for CP were not affected by the feeding speed. However, since the texture of the polished area of IP is not so good as S-s-P, the later is the most favourite model in CP. All the results have proven the correctness of the CPC and the theoretical conclusion, which is useful for the engineering application of S-s-P model of bonnet tool.