Jian-Wei Lin

A Novel Query Tree Protocol with Bit Tracking in RFID Tag Identification

Tag anticollision has long been an important issue in RFID systems. To accelerate tag identification, some researchers have recently adopted bit tracking technology that allows the reader to detect the locations of collided bits in a collision slot. However, these methods still encounter the problem of too many collisions occurring at the beginning of identification. This paper proposes an optimal query tracking tree protocol (OQTT) that tries to separate all of the tags into smaller sets to reduce collisions at the beginning of identification. Using bit tracking technology, OQTT mainly adopts three proposed approaches, bit estimation, optimal partition, and query tracking tree. Bit estimation first estimates the number of tags based on the locations of collided bits. Optimal partition then determines the optimal number of the initial sets based on this estimation. Query tracking tree splits a set of collided tags into two subsets using the first collided bit in the tag IDs. This paper analyzes the efficiency of OQTT, which represents how many tags can be identified in a slot. Results show that its efficiency is close to 0.614, the highest efficiency published to date. The simulation results further show that OQTT outperforms other existing algorithms.

Enhanced Mechanisms for Navigation and Tracking Services in Smart Phones

Combining Global Positioning System (GPS) and Short Message Service (SMS), this paper develops a realistic system, called Mobile Navigation and Tracking System (MNTS), to provide navigation and target tracking services. MNTS is an Android based mobile application which integrated many enhanced mechanisms for navigation and target tracking services. MNTS not only provides users with the GPS navigation capability, but also supports Quick Response (QR) code decoding, nearby scenic spot searching, friend positioning and target tracking. In target tracking, MNTS utilizing SMS mainly adopts two proposed novel approaches: location prediction and dynamic threshold to reduce the number of short message transmissions while maintaining location accuracy within an acceptable range. Location prediction utilizes the current target’s location, moving speed, bearing to predict its next location. When the distance between the predicted location and the actual location exceeds a threshold, the target sends a short message to the tracker to update the actual location. Based on the movement speed of the target, the threshold is dynamically adjusted to balance the location accuracy and the number of short messages. Furthermore, as MNTS is free and open-source software, service providers or developers can easily extend their own services based on this system.

A tracking system using location prediction and dynamic threshold for minimizing SMS delivery

In this paper, a novel method called location-based delivery (LBD), which combines the short message service (SMS) and global position system (GPS), is proposed, and further, a realistic system for tracking a targets movement is developed. LBD reduces the number of short message transmissions while maintaining the location tracking accuracy within the acceptable range. The proposed approach, LBD, consists of three primary features: Short message format, location prediction, and dynamic threshold. The defined short message format is proprietary. Location prediction is performed by using the current location, moving speed, and bearing of the target to predict its next location. When the distance between the predicted location and the actual location exceeds a certain threshold, the target transmits a short message to the tracker to update its current location. The threshold is dynamically adjusted to maintain the location tracking accuracy and the number of short messages on the basisof the moving speed of the target. The experimental results show that LBD, indeed, outperforms other methods because it satisfactorily maintains the location tracking accuracy with relatively fewer messages.

A Manageable Web-based Video Streaming System for On-Line Monitoring of Remote Laboratory Experiment

The proposed video streaming system, which is capable of handling multiple concurrent stream processes, enables clients to view live video of their interested instruments. Particularly, a system administrator can centralizedly control and manage the live video services via an administrative Web page. Some evaluation concerning CPU utilization and bandwidth consumption of this system have been presented also.

Efficient development of a web-based environmental testing system using a novel two-layer software architecture

This work proposes a two‐layer software architecture and design considerations for the efficient development of a Web‐based environmental testing system. The efficiency of developing such a system can be significantly improved since the upper layer, called the Web application, can immediately employ the uniform interface and follow the call flow provided in the lower layer, called the COM component. The COM component particularly addresses the integration of various instrument control mechanisms and the concurrency issue, while the Web application addresses database, security, modularity, and graphic user interface (GUI) issues. Moreover, based on the proposed software architecture and design considerations, a Web‐based environmental testing system, called the Web‐based Automatic Measurement System (Web AMS), is developed to validate the efficiency of this architecture and address the above issues. The proposed synchronization mechanism, not only enables many experiments to share one Digital Multi‐Meter (DMM) simultaneously, but also allows many remote clients to monitor the status of operating devices in a progressing experiment concurrently.

A Web-based Environmental Experiment System Using Microsoft .NET and COM

A Web-based environmental experiment system based on database, Microsoft .NET, and COM (component object model) technology is presented. The efficiency of developing such an application has promoted since the Web application can immediately refer the developed COM component, which integrates all connected device and different technologies of instrument control. Since the synchronization mechanism is also adopted for all devices in the developed COM component, the system guarantees not only two individual experiments can share one digital multimeter simultaneously, but also clients can monitor the status of devices while some experiment are already progressing

A Timeliness-Aware Retransmission Mechanism for Partially Reliable Transport Protocols to Enhance Performance of Multimedia Applications

The partially reliable transport protocol can enhance the quality of services (QoS) of multimedia applications because it reliably transmits some packets and unreliably transmits other packets. Nevertheless, determining which packets require reliable, i.e., these packets will be retransmitted if they were lost, significantly influences the performance of multimedia applications. For the determination, existing approaches adopt a fixed threshold or require information from other layers. This paper proposes a Timeliness-aware Retransmission Mechanism (TRM) that dynamically determines which lost packets should be retransmitted without any information provided from other layers. The receiver using TRM determines a threshold, which is the packet sequence number having timeliness, according to the packet consumed rate and the Round-Trip Time (RTT). Thus the sender retransmits lost packets that can timely arrive, namely, the packets have sequence numbers larger than this threshold. Simulation results shows that PR-DCCP, a partially reliable transport protocol, with TRM can efficiently increase the Decodable Frame Ratios (DFRs), which represents QoS, and decrease the Useless Data Received Ratios (UDRRs), which represents the bandwidth waste. In the simulations, TRM can achieve 8.6 ~ 10.6% DFR improvement and 15.1% ~ 17.6% UDRR improvement on average, compared with other retransmission methods.

Using sequence number compensation to design DCCP partial reliability extension

Datagram Congestion Control Protocol (DCCP), possessing congestion control and unreliable transmission, specially suits real-time multimedia applications. Nevertheless, losses of key packets will cause a substantial decline on quality of services (QoS) in some applications. This paper proposes a DCCP partial reliability extension (PR-DCCP) that can retransmit lost packets as needed. Since DCCP uses an incremental sequence number, the retransmitted packets cannot utilize their original sequence number. To solve this problem, PR-DCCP adopts sequence number compensation, which appends an offset to the retransmitted packet; thus the receiver can use the sequence number of this retransmitted packet and the attached offset so as to re-obtain the original sequence number. The simulation uses two performance metrics: Decodable Frame Ratio (DFR) representing QoS, and Useless Data Received Ratio (UDRR) representing the bandwidth waste. These are used to evaluate different transport protocols, namely, PR-DCCP, DCCP, SCTP, TCP, and UDP. Simulation results show that PR-DCCP has the better DFR and UDRR than other transport protocols in almost all cases. For various movies, a DFR of PR-DCCP is 1.2% – 12.4% higher than that of DCCP; while UDRR is lower by 73.2% – 85.1%. Furthermore, the reliability policies to determine which packets require reliability are investigated.

Manageable and Extensible Video Streaming Systems for On-Line Monitoring of Remote Laboratory Experiments

To enable clients to view real-time video of the involved instruments during a remote experiment, two real-time video streaming systems are devised. One is for the remote experiments which instruments locate in one geographic spot and the other is for those which instruments scatter over different places. By means of running concurrent streaming processes at a server, multiple instruments can be monitored simultaneously by different clients. The proposed systems possess excellent extensibility, that is, the systems can easily add new digital cameras for instruments without modifying any software. Also they are well-manageable, meaning that an administrator can conveniently adjust the quality of the real-time video depending on system load and visual requirements. Finally, some evaluation concerning CPU utilization and bandwidth consumption of the systems have been evaluated to verify the effectiveness of the proposed solutions.

A high-performance and well-manageable distributed measurement laboratory with an object-oriented approach

The distributed measurement laboratory (DML) can provide users with the capability of performing and practicing their experiments in a transparent manner on remote instruments located in different geographic areas and connected with a wide area network. In this article, we propose a high‐performance and well‐manageable DML, named HPWM, which is characterized by three main novel features: (1) using .NET Remoting to provide better network performance and having scalable and extendable architecture; (2) using Asynchronous JavaScript and XML (AJAX) to provide an efficient and lightweight Graphic User Interface (GUI) without browser plug‐ins; and (3) offering adequate management functionalities to well manage users and instruments and establishing their relationships. The software structure used for developing HPWM is also described. Finally, HPWM has been tested in the academic and industrial education and has shown its correctness and effectiveness.