Zhiyi Fang

The Design and Implementation of a RSSI-Based Localization System

Existing localization algorithms in Wireless Sensor Network (WSN) can be divided into two categories: range-based and range-free. Most of the range-based localization algorithms proposed made use of the Received Signal Strength Indication (RSSI) to make an estimation of the distance between transmitter and receiver. Based on our experiments, there is no relationship between RSSI and distance in indoor situations. But the outdoor experiments show that RSSI is closely related with distance, direction of antenna, the height of nodes above the ground and obstructions. The Gaussian model by curve fitting the average RSSI value with distance resulted the formulation that can be used to compute the distance between unknown node and its neighboring nodes. Then, by applying Trilateration method, a localization system was implemented. This system are specially designed for outdoor without obstructions, tiny variance of physical conditions and all sensor nodes should be placed 2 meters higher than playground. Finally, some errors were analyzed in detail and corresponding proposals were given.

An Agent-Based Intelligent Transport System

The rapid development of modern transportation brings tremendous challenges to the intelligent transport system. Intelligent computer supported cooperative work (CSCW) and wireless communication technology are more and more used in intelligent transport systems. In this paper, we adopt wireless communication technology: ad hoc network, GPS, GIS, WIMAX, and WiFi, and design an intelligent transport system based on a multi-agent system, and implement the design in our experimental environment. The proposed system will help vehicle drivers make quick responses to the road emergency. Meanwhile it will also help vehicle drivers around the emergency area to make appropriate decisions.

A Framework of Agent-Based Collaborative Intelligent Transport System

Intelligent cooperative decision-making and wireless communication are more and more used in intelligent transport systems. In this paper, According to the thought of agent-oriented collaborative and use wireless communication, we construct an intelligent transport system framework based on the agent, and set up the experimental environment to realize this construction. It achieves the vehicles individual regarding the urgent region in event agile response, simultaneously can cause outside the urgent region the vehicles individual to make the corresponding decision-making.

A Personalized CAI Courseware System

The network-based CAI (Computer Assisted Instruction) courseware system,Compared with the traditional one, has its advantages and disadvantages. After give an introduction to the ongoing development of distance learning and E-learning. This paper combined a hierarchical Level-Generate algorithm with the Data Mining theory, to provide the students with a personalized courseware system by building a CAI courseware tree. With courseware tree, the system can recommend useful materials to each student based on the performance of individual student. If the system computes the personality of each student, the complexity is higher and hard to implement. Thus, mining on students is necessary. Using Hamming distance theory, students were clustered into different groups based on the courseware they accessed. Computer Assisted Instruction, abbreviated as CAI, is now widely used in all kinds of educational applications, especially the distant learning and network-based tutor systems, while the network technology is prevailed all over the world. However, the distance learning and most applications of the courseware are restricted to traditional classroom and only used locally. The Internet profoundly changed the way people communicate and becomes available everywhere. The traditional teaching system is now challenged by the Internet and many researchers exert great effort on developing the network based learning systems to assistant the traditional classroom teaching. The network based CAI courseware, with its vivid appearance, interchangeable ability and the breakthrough of time and space, declares an evaluation to the traditional teaching model. During the past several years, researchers provide the educators with some tools that auxiliary the traditional teaching systems. In (1), C. Romero and S. Ventura survey the application of data mining to traditional educational systems, especially web-based well-known learning content management systems, and adaptive and intelligent web-based educational systems. The author firstly compared the difference between e-commerce and e-learning. The authors also distinguished between three different types of web-based education systems: particular web-based courses, well-known learning content management systems, and adaptive and intelligent web-based educational systems. Then, four kinds of data mining techniques were presented: statistics and visualization; clustering, classification and outlier detection; association rule mining and pattern mining; and text mining.

A CA-Based Security e-Government System

The development of electronic government (e-Government) requires the high security of network. PKI/CA is an effective solution. This paper puts forward the safe solution of e-Government based on PKI/CA, and puts emphasis on how to set up the signing and issuance center of digital certificate and the registration authority center of digital certificate

DTDS: LAN Agent-Based Dynamic Transmit Direction Search Algorithm in P2P Network

We proposed the LAN Dynamic Transmit Direction Search Algorithm - DTDS algorithm. We expounded the basic thought and the design principle of DTDS algorithm, carried on the theoretical analysis to such as aspects of its accuracy and parameter values. At last we took the simulation experiment, carried on the quantification analysis with the experimental datum to the algorithm, drew up the graph through using experimental datum, and presented the network search process through the image. We make the complex question to be clearer and direct-viewing. The simulation experiment verifies DTDS algorithm greatly improves the search speed while doesnt reduce the network coverage.

An Improved MIEhD Backoff Algorithm in IEEE 802.11 MAC Layer

This paper first described the IEEE 802. 11 MAC layer access control mechanism DCF. Next, we analysis the basic and improved DCF back-off algorithm, and then we proposed exponential-half DCF back-off algorithm MIEhD. This algorithm is easy to implement and has excellent performance when there is small scale of nodes and avoiding the shortcomings of basic algorithm when there is large scale of nodes.

Research on Direction Search Algorithm Based on LAN Agent in P2P Network

In view of the problem of slow search speed conduced by failure Topology and limited retransmission nodes quantity in MDBS search algorithm; we proposed the LAN Agent-Based Direction Search algorithm-ABDS algorithm. We expounded the basic thought and design principle of ABDS algorithm and carried on the theoretical analysis to such as aspects of its accuracy and parameter values. The analysis results show that ABDS algorithm greatly improves the search speed while doesnt reduce the network coverage.

Security Analysis for SOA-SCA Based SDO and Solutions for 3 Capability Problems

As an open architecture, SOA (Service-Oriented Architecture) provides developers with more freedom. However, its security problem goes from bad to worse. By taken a bank transfer with proxy as an example, this paper analyzed the security issue of SDO (Service Data Object) data model and proposed an mechanism to make sure that the integrity, confidentiality and non-repudiation of SDO data model are preserved by applying encryption/decryption, digest, digital signature and so on. Finally, by applying WIN and WPS tools, this mechanism was developed and its performance was evaluated.

The Application of Personalized Distribution System in Distributed Teaching Resource

Chiefly aimed at the distributed resource search status in the present educational field, this paper brought the conception of individuation search based on the consumers interest. The relevant models of individuation analysis and individuation resource searching were designed in this paper. At the same time, self-study arithmetic, the method of information searching and information filtering, was also presented. The shortcomings of traditional information distribution, including low distribution rate and lack of intelligence, were deliberately considered. Finally, the intellectual management of the distributing center of educational resource was implemented.