School of Advanced Technology

School of Advanced Technology
Xi'an Jiaotong-Liverpool University
111 Ren'ai Road Suzhou Dushu Lake Science and Education Innovation District , Suzhou Industrial Park
Suzhou,Jiangsu Province,P. R. China,215123
1. Special issue on computational intelligence for social media data mining and knowledge discovery

Author:Li, Y;Shyamasundar, RK;Wang, XH


2. Usable Authentication Mechanisms for Mobile Devices: An Exploration of 3D Graphical Passwords

Author:Yu, Z;Olade, I;Liang, HN;Fleming, C


Abstract:Current authentication systems in mobile devices such as smart phones have many shortcomings. Users tend to use simple textual passwords such as PINs, which are easily cracked by intruders. Meanwhile, graphical passwords suffer from shoulder surfing attack In this paper, a new authentication system using 3D graphical passwords, will be proposed and tested to offer more security for mobile devices. This authentication system allows users to interact with the 3D objects in a 3D virtual environment and these actions are tracked in the virtual environment and used to create unique passwords. Based on the previous studies of the 3D password scheme, this paper developed a simple testing program that enables users to create their own 3D password easily. At the end of the paper, some improvements of the program and this authentication system are discussed.
3. Minimize Reactive Power Losses of Dual Active Bridge Converters using Unified Dual Phase Shift Control

Author:Wen, HQ;Su, B


Abstract:This paper proposed an unified dual-phase-shift (UDPS) control for dual active bridge (DAB) converters in order to improve efficiency for a wide output power range. Different operating modes of UDPS are characterized with respect to the reactive current distribution. The proposed UDPS has the same output power capability with conventional phase-shift (CPS) method. Furthermore, its implementation is simple since only the change of the leading phase-shift direction is required for different operating power range. The proposed UDPS control can minimize both the inductor rms current and the circulating reactive current for various voltage conversion ratios and load conditions. The optimal phase-shift pairs for two bridges of DAB converter are derived with respect to the comprehensive reactive power loss model, including the reactive components delivered from the load and back to the source. Simulation and experimental results are illustrated and explained with details. The effectiveness of the proposed method is verified in terms of reactive power losses minimization and efficiency improvement.
4. Application of Hough Transform Feature Extraction to Reduce Angular Vibration in Images Captured from Moving Objects

Author:Afolabi, D;Man, KL;Liang, HN;Zhang, N;Lim, EG;Wan, KY


Abstract:This paper details an ongoing research aimed at developing computational approach to reducing/eliminating vibration and light glare in images captured by digital cameras especially when the scene contains moving objects or the camera is mounted on a moving vehicle / flying drone. The algorithms developed are focused at real-time image acquisition where the enhanced/corrected images are need almost immediately after they are captured. The results show that these methods of reducing the stated problems are effective and it can be further developed for various applications.
5. Impact of Parasitic Elements on RF Performance of Nanometre-Scale MOSFET Structures

Author:Lam, S


Abstract:A recently reported nanometre-scaled MOSFET structure with regrown source and drain is examined. The parasitic circuit elements are identified and quantitatively determined to estimate their impact on the transistor's RF performance. Due to the relatively large lateral parasitic capacitances from the gate electrode to the regrown source and drain regions, the current gain cut-off frequency f(T) of such a transistor is optimistically estimated to be 184 GHz which is not impressive for nanoelectronic devices with an effective gate length of 30 nm. However, with the significantly reduced parasitic series resistances due to the regrown source and drain structures together with the use of the metal gate, the maximum frequency of oscillation f(max) can attain to 820 GHz. This brings about an implication that device structure optimization to reduce the parasitic resistances has a dominant beneficial effect on the RF performance over the negative impact caused by the increased parasitic capacitances.
6. Three-Dimensional Local Energy-Based Shape Histogram (3D-LESH): A Novel Feature Extraction Technique

Author:Wajid, SK;Hussain, A;Huang, KZ


Abstract:In this paper, we present a novel feature extraction technique, termed Three-Dimensional Local Energy-Based Shape Histogram (3D-LESH), and exploit it to detect breast cancer in volumetric medical images. The technique is incorporated as part of an intelligent expert system that can aid medical practitioners making diagnostic decisions. Analysis of volumetric images, slice by slice, is cumbersome and inefficient. Hence, 3D-LESH is designed to compute a histogram-based feature set from a local energy map, calculated using a phase congruency (PC) measure of volumetric Magnetic Resonance Imaging (MRI) scans in 3D space. 3D-LESH features are invariant to contrast intensity variations within different slices of the MRI scan and are thus suitable for medical image analysis. The contribution of this article is manifold. First, we formulate a novel 3D-LESH feature extraction technique for 3D medical images to analyse volumetric images. Further, the proposed 3D-LESH algorithmic, for the first time, applied to medical MRI images. The final contribution is the design of an intelligent clinical decision support system (CDSS) as a multi-stage approach, combining novel 3D-LESH feature extraction with machine learning classifiers, to detect cancer from breast MRI scans. The proposed system applies contrast-limited adaptive histogram equalisation (CLAHE) to the MRI images before extracting 3D-LESH features. Furthermore, a selected subset of these features is fed into a machine-learning classifier, namely, a support vector machine (SVM), an extreme learning machine (ELM) or an echo state network (ESN) classifier, to detect abnormalities and distinguish between different stages of abnormality. We demonstrate the performance of the proposed technique by its application to benchmark breast cancer MRI images. The results indicate high-performance accuracy of the proposed system (98%%+/- 0.0050, with an area under a receiver operating charactertistic curve value of 0.9900 +/- 0.0050) with multiple classifiers. When compared with the state-of-the-art wavelet-based feature extraction technique, statistical analysis provides conclusive evidence of the significance of our proposed 3D-LESH algorithm. (C) 2017 The Authors. Published by Elsevier Ltd.
7. Robust Localisation of Pedestrians with Cast Shadows Using Homology in A Monocular View

Author:Xu, M;Jia, TY;Lu, L;Smith, JS


Abstract:In this paper an object detection algorithm is proposed, which is robust in the presence of cast shadows and is based on geometric projections. The novelty of the work lies in the use of homology mapping of the foreground regions between different parallel planes within a monocular view, unlike some existing algorithms which depend on the use of multiple cameras. The results on an open video dataset are provided.

Author:Stankovic, N


Abstract:We report on our experience with two pedagogies over a two year period, using one approach in each academic year, but the learning outcome remained the same. The first approach, in the first year, was backed up by Ian Sommerville's textbook, and the second by Bruegge and Dutoit's. The students came from three different curricula, and the class size in the second year was three times that in the first year. The difference in the outcome and in the meeting of the learning outcome has been strongly in favour of the second pedagogy. In this paper we compare the outcomes, provide a number of examples that explain the issues that the students had to deal with, and how the change in the pedagogy has improved the quality of the laboratory work without changing the project framework itself.
9. Operation of 8-wavelength-radius 2-layer lenses

Author:Gray, D;Nikolic, N;Thornton, J


Abstract:Two competing 8-wavelength-radius 2-layer lens designs were identified in the literature. Both were analyzed by ray tracing and full wave simulation, as an initial step toward production by additive manufacturing for use at mm-wave frequencies. The conclusion of this initial study is that the relative permittivity 1.68 - 1.6 design appears to be best suited to production by laser sintering.
10. Moving shadow detection via binocular vision and colour clustering

Author:Lu, L;Xu, M;Smith, JS;Yan, YY

Source:IET COMPUTER VISION,2020,Vol.14

Abstract:A pedestrian segmentation algorithm in the presence of cast shadows is presented in this study. The novelty of this algorithm lies in the fusion of multi-view and multi-plane homographic projections of foregrounds and the use of the fused data to guide colour clustering. This brings about an advantage over the existing binocular algorithms in that it can remove cast shadows while keeping pedestrians' body parts, which occlude shadows. Phantom detection, which is inherent with the binocular method, is also investigated. Experimental results with real-world videos have demonstrated the efficiency of this algorithm.
11. An Improved Brain Storm Optimization with Differential Evolution Strategy for Applications of ANNs

Author:Cao, ZJ;Hei, XH;Wang, L;Shi, YH;Rong, XF


Abstract:Brain Storm Optimization (BSO) algorithm is a swarm intelligence algorithm inspired by human being's behavior of brainstorming. The performance of BSO is maintained by the creating process of ideas, but when it cannot find a better solution for some successive iterations, the result will be so inefficient that the population might be trapped into local optima. In this paper, we propose an improved BSO algorithm with differential evolution strategy and new step size method. Firstly, differential evolution strategy is incorporated into the creating operator of ideas to allow BSO jump out of stagnation, owing to its strong searching ability. Secondly, we introduce a new step size control method that can better balance exploration and exploitation at different searching generations. Finally, the proposed algorithm is first tested on 14 benchmark functions of CEC 2005 and then is applied to train artificial neural networks. Comparative experimental results illustrate that the proposed algorithm performs significantly better than the original BSO.
12. Computation of macro-fiber composite integrated thin-walled smart structures

Author:Zhang, SQ;Zhang, SY;Chen, M;Bai, J;Li, J


Abstract:Due to high flexibility, reliability, and strong actuation forces, piezo fiber based composite smart material, macro-fiber composite (MFC), is increasingly applied in various fields for vibration suppression, shape control, and health monitoring. The complexity arrangement of MFC materials makes them difficult in numerical simulations. This paper develops a linear electro-mechanically coupled finite element (FE) model for composite laminated thin-walled smart structures bonded with MFC patches considering arbitrary piezo fiber orientation. Two types of MFCs are considered, namely, MFC-d31 in which the d(31) effect dominates the actuation forces, and MFC-d33 which mainly uses the d(33) effect. The proposed FE model is validated by static analysis of an MFC bonded smart plate.
13. Automatic Building and Floor Classification using Two Consecutive Multi-layer Perceptron

Author:Cha, J;Lee, S;Kim, KS


Abstract:Key issues of indoor localization is taking full advantages and overcoming its disadvantages. indoor localization based on Wi-Fi fingerprinting attracts researchers' attentions since it does not require new infrastructure and devices. Many devices such as smart phones and laptops, which have a function to capture Wi-Fi signals, can be used for Wi-Fi fingerprinting. However, due to unreliable Wi-Fi signals, there are still difficulty to achieve high positioning accuracy. The unreliable signal disturbs devices to find their locations. As a result, getting localization with devices sometimes makes a wrong decision in building classification. It is useless for people to find a destination floor if they are in different building. In this paper, we propose two consecutive multi-layer perceptrons to get more precise localization. With sumple structure, we get better performance and show precise decision results in building classification, which is critical in Wi-Fi fingerprinting. We use UJIndoorLoc dataset which is open dataset.
14. MidSens'09 - International Workshop on Middleware Tools, Services and Run-Time Support for Sensor Networks, Co-located with the 10th ACM/IFIP/USENIX International Middleware Conference Preface

Author:Michiels, Sam ; Hughes, Danny

Source:MidSens'09 - International Workshop on Middleware Tools, Services and Run-Time Support for Sensor Networks, Co-located with the 10th ACM/IFIP/USENIX International Middleware Conference,2009,Vol.

15. Cascode GaN Power Device and Its Application in Wireless Power Transmission System

Author:Qian Hongtu;Zhu Yongsheng;Deng Guangmin;Liu Wen;Chen Dunjun;Pei Yi

Source:Journal of Power Supply,2019,Vol.17

Abstract:To achieve a higher power conversion efficiency, a cascode structure based on 650 V gallium nitride high electron mobility transistor(GaN HEMT) was introduced, together with its applications in wireless power transmission. From the aspect of GaN HEMT design, the effects of field plate design on capacitance and electric field were discussed through simulations. The fabricated cascode device had a leakage current of 2 muA at drain-source voltage of 650 V. At 400 V, the input capacitance C_(iss), the output capacitance C_(oss) and the reverse transfer capacitance Crss were 1 500 pF, 32 pF and 12 pF, respectively, and the dynamic on-resistance increased by about 16%%. Based on the design of this cascode device, a wireless charging prototype with operation frequency of 240~320 kHz and full-load power of 1 kW was designed and presented. Compared with the equivalent Si device, its efficiency was obviously higher within the load range of 200~1 000 W, with the peak efficiency higher than 95%%.
16. A Method for Rapid Measurement of Intracellular Lipid Accumulation

Author:Xiong Yiwei;Zhang Junlong;Yang Tian;Zhang Bailing;Jiang Lin


Abstract:Objective: To propose a fast and reliable method for the determination of intracellular lipid accumulation. Method: Lipid accumulation in HepG2 cells were induced by oleic acid. Lipid droplets were stained with BODIPY 493/503 and measured with fluorescent image processing using Matlab or ImageJ. The images results were compared to those of Adipophilin,a widely served marker for lipid accumulation,which were determined from protein and mRNA levels by Western blotting and qPCR. Result: By processing fluorescent images using BODIPY 493/503 staining for lipid droplets and comparing data outputs with Matlab and ImageJ, a method using Matlab as image processing platform was established for the determination of intracellular lipid accumulation ; a 1. 41 - fold increase in oleic acid - induced lipid accumulation was detected by fluorescent image processing, which were in accordance with the markedly enhancement in Adipophilin protein levels (2. 07 - fold) and mRNA levels (1. 53 - fold). Conclusion: The method combining fluorescent staining and image processing shall help analyze the intracellular lipid accumulation both rapidly and accurately.
17. AlGaN/GaN Metal-Insulator-Semiconductor (MIS)-HFETs Based DC-DC Boost Converters with Integrated Gate Drivers

Author:Cui, M;Bu, QL;Cai, YT;Sun, RZ;Liu, W;Wen, HQ;Lam, S;Liang, YC;Mitrovic, IZ;Taylor, S;Chalker, PR;Zhao, CZ


Abstract:This study proposed a 100 kHz, 5V/11V boost converter with an integrated gate driver for a power switching device using recessed E-mode MIS-HFETs. The integrated gate driver consisting of multi-stages DCFL (Direct-Coupled FET Logic) inverters and a buffer stage, has large input swing (up to 10 V) and wide noise margin with gate dielectric, which benefits applications requiring large gate swing without any additional drivers or level shifters. The impact of transistor size on rise times and fall times have been studied. Either buffer stage or larger width of DCFL inverter can reduce rise times from 2.4 mu s to less than 0.5 mu s at 100 kHz, so the output voltage of boost converter is increased by 10 %% at a duty cycle of 0.7. However, large buffer width can result in high gate overshoot and oscillation, indicating careful design to balance switching speed and oscillation.
18. The design and simulation of p-type Si/SiGe Terahertz quantum cascade lasers

Author:Chen, QY;Wu, JJ;Fang, Z;Zhao, CZ


Abstract:To prolong upper state lifetime in p-type Si/Si1-xGex Terahertz quantum cascade lasers, a new active region is designed in this work. Using 6 x 6 k . p theory, the eigenvalues and wavefunctions of heavy holes and light holes are firstly calculated in a single SiGe quantum well. The design in the active region of this THz Si/Si1-xGex quantum cascade lasers is then investigated. This work presents a SiGe quantum cascade laser with about 6.84 THz emission in the diagonal transition. The calculations show that about 32 ps of the upper state lifetime and about 9 cm(-1) of optical gain are obtained, which are enhanced when compared to previous designs. (C) 2013 Elsevier Ltd. All rights reserved.
19. Modeling and Verification of NCL Circuits Using PAT

Author:Ma, JM;Man, KL;Lim, EG;Zhang, N;Lei, CU;Guan, SU;Jeong, TT;Seon, JK

Source:CEIS 2011,2011,Vol.15

Abstract:NULL Conventional Logic (NCL) is a Delay-Insensitive (DI) clockless paradigm and is suitable for implementing asynchronous circuits. Efficient methods of analysis are required to specify and verify such DI systems. Based on Delay Insensitive sequential Process (DISP) specification, this paper demonstrates the application of formal methods by applying Process Analysis Toolkit (PAT) to model and verify the behavior of NCL circuits. A few useful constructs are successfully modeled and verified by using PAT. The flexibility and simplicity of the coding, simulation and verification shows that PAT is effective and applicable for NCL circuit design and verification. (C) 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of [CEIS 2011]
20. FMCW Rail-mounted SAR: porting spotlight SAR imaging from MATLAB to FPGA

Author:Melnikov, A;Le Kernec, J;Gray, D


Abstract:In this work, a low-cost laptop-based radar platform derived from the MIT open courseware has been implemented. It can perform ranging, Doppler measurement and SAR imaging using MATLAB as the processor. In this work, porting the signal processing algorithms onto a FPGA platform will be addressed as well as differences between results obtained using MAT LAB and those obtained using the FPGA platform. The target FPGA platforms were a Virtex6 DSP kit and Spartan3A starter kit, the latter was also low-cost to further reduce the cost for students to access radar technology.
Total 1,976 results found
Copyright 2006-2020 © Xi'an Jiaotong-Liverpool University 苏ICP备07016150号-1 京公网安备 11010102002019号