Canfeng Chen

Mobile E-commerce model based on social network analysis

Abstract With the development of Internet technology and the increasing popularity of mobile terminals, mobile E-commerce has become a convenient tool in our daily life. In a mobile E-commerce system, how to effectively establish and evaluate trust between seller and buyer is a hotspot. Whether a buyer knows and trusts a seller often strongly influences purchasing decisions, especially in customer-to-customer (C2C) E-commerce or second-hand exchange market. This paper proposes a social network model on the mobile E-commerce system, which can give recommendation values between buyers and sellers in terms of their social relationship, actual geographical distances and historic deal records etc. Experiment results show that the proposed model can effectively help users to make the decision whether and with whom to make a deal by using the recommendation values. In addition, the proposed model also has better security feature than the normal E-commerce system.

A Novel Compatible Hardware Expansion Method Based on General Memory Interface

A new hardware expansion method based on memory card slot has been proposed in this paper, which can make the extended equipment more compatible with hosts that are running on different platforms. The main idea of our method is based on the fact that the logic interface between client devices and the higher level is memory card, and memory host controllers and drivers are all compatible with expansion memory cards; therefore, the driver of the extended equipment can communicate with the equipment smoothly through files in the operating system instead of employing API at the lower level. In this way, the host that supports memory cards will support the extended equipment, which brings much advantage in cross-platform compatibility and transportability. As an example to verify the proposed method, the hardware design framework for Zigbee transceiver based on SD slot is introduced.

Decomposition and compression for ECG and EEG signals with sequence index coding method based on matching pursuit

Abstract An efficient compression method is proposed by encoding the sequence index of atoms based on matching pursuit (MP) algorithm with over-complete Gabor dictionary, which has the merit to adjust the compression ratio (CR) according to the practical request with low distortion. It is also combined with genetic algorithm (GA) to reduce the computation complexity. Then, the validity of this method is verified by applying it in the compression of electrocardiography (ECG) and Electroencephalography (EEG) signals. The simulation results show that the CR can be achieved at 18:1 with only 1.06% and 2.15% reconstruction errors on ECG and EEG signals respectively. It has higher CR and less reconstruction errors compared to that of the traditional methods, and noise suppression effect is also presented.

uSD Card: a plug&play solution for mobile device to access wireless sensor networks

The rapid development of wireless sensor network applications and mobile devices has brought the need for a universal plug & play solution to access wireless sensors and sensor network on the go. By reusing the legacy SD memory card slot built in mobile devices, we have developed a platform-independent method to extend low power short range connectivity for mobile devices, namely, universal Sensor Data (uSD) card. The paper gives a comprehensive description to hardware and software design for uSD card, and provides some examples on implementing mobile sink function on mobile devices.

A parameter estimation method for FH signal based on SPWVD

Abstract A parameter estimation method for frequency hopping (FH) signal in low signal-to-noise ratio (SNR) circumstance is proposed by using the derivation of the time-frequency backbone, overlapped multiple windows and iteration-based adaptive-threshold based on smoothed pseudo wigner-ville distribution (SPWVD). Through the derivation process of the time-frequency backbone, the mutation pulses are presented at the hopping times, so that the hopping features are magnified. With the help of iteration-based adaptive-threshold method, the false hopping points are removed, and the hop duration can be calculated with the mutation pulses. The simulation result shows that better estimation performance could be achieved at low SNR, which is improved about 8 dB compared with the traditional method.

The blind demodulation scheme based on MP algorithm in chirp-BOK UWB system

Abstract In this paper, a blind demodulation scheme for chirp-binary orthogonal keying (BOK)-ultra wide band (UWB) system was proposed based on matching pursuit (MP) algorithm. The scheme was validated in additive white Gaussion noise (AWGN) and indoor multi-path channels that suggested by the IEEE P802.15 criterion. From the simulation results, it shows that the performance of the proposed MP method is consistent well with that of the traditional coherent method in communication circumstance with high quality requirement, and the performance difference of MP method and coherent method is less than 0.8 dB when the bit error rate (BER) is set as 0.001. As the requested BER getting small, the MP method has a comparable performance with the coherent method. It also presented an efficient way for spectrum sharing with other communication systems.

Design and implementation of context composition framework for end-user programming

Rich context available creates varied applications on mobile device and makes end-user possible to customize personalized context-aware application. Meanwhile, problems arise that how to realize the service composition and present the service easy for end-user programming. In this paper, we refer to the notion of service component, design and implement a Context-Source Service Composition Prototype Framework on Maemo platform on mobile device and deploy a serial of context-source services to inspect and verify our system.

A Service Composition Method for Mobile Environment

A service composition method for mobile environment is put forward to build new application system based on existing mobile services and service composition technologies. This method accomplishes semi-automatic service composition based on service composition template. Service component technology is used to manage heterogeneous services in mobile environment. By integrating distributed, dynamic service discovery mechanism, and service management/replacement mechanism based on QoS, this method will efficiently support service composition process in mobile environment.