Papers by Author: Quan Liu

Abstract: Brain computer interfaces (BCIs) have become a research hotspot in recent years because of great potentials to help disabled people communicate with the outside world. Among different paradigms, steady state visual evoked potential (SSVEP)-based BCIs are commonly implemented in real applications, because they provide higher signal to noise ratio (SNR) and greater information transfer rate (ITR) than other BCI techniques. Various algorithms have been employed for SSVEP signal processing, like fast Fourier transform (FFT), wavelet analysis and canonical correlation analysis (CCA). In this paper, a new method based on multiple signal classification (MUSIC) was proposed for SSVEP feature extraction. The experimental results proved that it could provide higher frequency resolution and the recognition accuracy was excellent via adjusting some parameters.

Abstract: In this paper, discusses the design and realization of large file asynchronous upload and Broken-point continuingly-transferring based on ASP.NET MVC. At the first, brief review the traditional upload method based on HTTP(Hypertext transfer protocol) protocol and ASP.NET(C#), point out the existed malpractices, while introduce the basic principles of asynchronous upload and broken-point continuingly-transferring, and in-depth analysis of the design and realization of the function of asynchronous upload and broken-point continuingly-transferring in ASP.NET MVC.

Abstract: Aero-engine pipeline is the cardiovascular of aero-engine, which directly affects the safety and reliability of planes. However, the pipeline has complex structure and is easily broken by the harsh operation environment. Therefore, the condition monitoring and fault diagnosis of aero-engine pipeline play one of the most important role to ensure the aero-engine safe and reliable. Fiber Bragg Grating Sensor (FBGS) owns several characteristics, such as anti-electromagnetic interference, corrosion resistance, small size, performance stability, long lifecycle, as well as easy to constitute distributed multi-point system. In this paper, a condition monitoring and fault diagnosis system for aero-engine pipeline, including online monitoring and offline diagnosis, is proposed. Moreover, online monitoring based on temperature and strain signals and offline fault diagnosis based on simulated vibration signals of aero-engine pipeline are explained in details. According to the experimental results, the proposed system is useful and effective.

Abstract: In this paper, discusses the design and realization of large file asynchronous upload and Broken-point continuingly-transferring based on ASP.NET MVC. At the first, brief review the traditional upload method based on HTTP(Hypertext transfer protocol) protocol and ASP.NET(C#), point out the existed malpractices, while introduce the basic principles of asynchronous upload and broken-point continuingly-transferring, and in-depth analysis of the design and realization of the function of asynchronous upload and broken-point continuingly-transferring in ASP.NET MVC.

Abstract: FBG (Fiber Bragg Grating) is especially suitable for the shafting operation condition monitoring of rotating machinery under the harsh working environment for a long time with its advantages of anti-electromagnetic interference, easy reuse, good stability, environmental adaptability and so on. The overall architecture of the shafting operation condition monitoring system based on FBG sensing network is proposed. In the system, FBG multi-channel distributed sensing network is used to fully apperceive the real-time operation condition information of the equipment. While the Windows Presentation Foundation (WPF) and 3-Dimensional Studio Max (3DMAX) technologies are used to realize the intuitive 3-Dimensional (3D) virtual display to monitor the equipment. Besides, the sensing information data stream is processed in real time to display the running state of the equipment. Also, mass sensing information is analyzed and stored by the real-time processing method. The stability and reliability of the proposed framework and key technology is verified by the system long-time implementation results.

Abstract: In this paper, an intelligent warehousing management system (IWMS) using Internet of Things is designed to facilitate the warehousing management. Firstly, the characteristics of IWMS are analyzed, together with some new advanced technologies and theories, such as RFID, Zigbee and heterogeneous network are introduced. Then, the architecture of IWMS is developed and the related management system is accomplished as well. Finally, through the implementation of a prototype system in practical working environment, the operation results show the IWMS can facilitate storekeeper to manage the warehouse and improve logistics capability efficiently.

Abstract: Cloud manufacturing is a new kind of advanced service-oriented network manufacturing paradigm. There are two kinds of nodes in this network manufacturing environment: manufacturing service nodes (service providers) encapsulated by manufacturing resources and task nodes (service customers). One of the bases of building up the collaborative relationships between customers and providers in cloud manufacturing environment is their reciprocal trust. However, vicious, mendacious, and inveracious information makes it quite difficult for customers to find reliable and high-quality providers to form virtual manufacturing systems for efficiently responding to market demands in cloud manufacturing environment, viz. service consumers often have insufficient information on service providers. The trustworthy network manufacturing environment is a prerequisite to implementation of cloud manufacturing. In this paper the notion of human trust is extended to the cloud manufacturing. A computational trust model which combines the direct computational reliability and the computational reputation is presented, and the simulating result confirms it valid.

Abstract: Blades are the one of significant component in aero-engine, 70% mechanical faults are caused by blades failure. In this paper, a spectrum analysis on straining signals of rotating blades has been done through fiber Bragg grating sensors (FBGs) and Hilbert transform (HT). In order to obtain the dynamic characteristics of rotating blades, dynamic strain was monitored by four FBGs located on one blade in aero-engine with rotating speed up to 840 rpm. According to the measured and analyzed results, the FGBs are effective to measure the dynamic strain of blade in operating aero-engine. Moreover, it is capable of providing the state of rotating blades based on the envelope analysis in HT.

Abstract: Being a kind of actual resources, manufacturing equipment resources (MERs) need to be virtualized and encapsulated into services. Our proposed works mainly focus on manufacturing capability of MERs that is consisted of two aspects: static functional capability and dynamic production capability, and relationship between related concepts so as to model MERs by ontology web language (OWL) that is based on semantic. In this paper, firstly, ontology based methodology within manufacture field is developed according to cloud manufacturing characters. Secondly, manufacturing capability is studied from functional attribute capability and production capability, then, the related concepts classes and relationship are analyzed, with the special properties defined to describe these classes based on semantic. Thirdly, the built in model is described by OWL (ontology web language) using protégé tool and an instance of MER is built based on the proposed model to express its manufacturing capability. Finally, this model is applied to Cloud MERs service platform, which is constructed for a given enterprise group, to provide MERs services. Moreover, Web Service is used in the platform to realize the sharing of the provided services.

Abstract: Soft-output complex list sphere decoding algorithm is a low-complexity MIMO detection algorithm and its BER performance approximates that of Maximum-Likelihood. However, it has a problem of not fixed complexity, and which make it very difficult to implement. To resolve this and try best to retain the advantages of the algorithm, a modified algorithmfixed complex list sphere decoding algorithm was proposed. Based on LTE TDD system, this paper studies the performance of the FCLSD algorithm. The simulation results show that: the BER performance of the FCLSD algorithm is close to that of the CLSD algorithm. However, when the number of antennas and modulation order increasing, the FCLSD algorithm is non-constrained of spherical radius and has fixed complexity. In addition, hardware implementation of the FCLSD algorithm could be carried out by parallel processing, thereby greatly reducing the algorithm complexity. So it is a high-performance algorithm of great potential.