Indoor localization systems-tracking objects and personnel with sensors, wireless networks and RFID

Advances in ubiquitous mobile computing and rapid spread of information systems have fostered a growing interest in indoor location-aware or location-based technologies. In this paper we will introduce the primary technologies used in indoor localization systems by classifying them in three categories: Non-RF technologies, Active-RF technologies and Passive-RF technologies. Both commercialized products and research prototypes in all categories are involved in our discussion. The Passive-RF technologies are further divided into “Mobile tag” and “Mobile reader” systems. We expect such classification can cover most of the indoor localization systems. Features of these systems are briefly compared at the end of this paper

Multirate control in internet-based control systems

One of the major challenges in Internet-based control systems is how to overcome the Internet transmission delay. In this paper, we investigate the potential of using the multirate control scheme and the time-delay compensation to overcome the Internet transmission delay. A two-level hierarchy is used for the Internet-based control systems.At the lower level, a local controller is implemented to control the plant at a higher frequency. At the higher level, a remote controller is employed to remotely regulate the desirable set-point at a lower frequency for the local controller. A compensator located at the feedback channel is designed to overcome the time delay occurring in the transmission from the local site to a remote site. Another compensator in the feedforward channel is designed to compensate the time-delay occurring in the control action transmission. The simulation and experimental application results illustrate that the multirate control scheme with the time delay compensation offers a promising way to efficiently reduce the effect of Internet time delay on control performance

Reducing the transmission and reception powers in the AODV

The transmission power and the reception power are the main source of energy consumption in wireless sensor nodes. Therefore, reducing the amount of consumed power through the transmission and reception processes in the routing protocol will lead to an increase in the lifetime of the wireless sensor network and distribute the consumed power among the wireless sensor nodes. This paper proposes a mechanism to reduce the transmission and reception power for the frequently used nodes. This proposed techniques and a hybrid technique with the power consumption distribution technique in have been compared to the original Ad hoc On-Demand Distance Vector (AODV) routing protocol. Simulation results based on NS-2 showed that the hybrid technique and the proposed mechanism have better performance than the original AODV routing protocol. The new mechanism and the hybrid technique have increased the lifetime of the wireless sensor network by around 40%, and 70% respectively

RFID based automatic speed limit warning system

Speeding is one of the major causes of road accidents. As drivers usually claim they exceed the speed limit unintentionally, having an in-vehicle automatic speed limit warning system could help to prevent a significant number of speeding and accidents from happening. Existing systems cannot provide consistent and satisfactory performance. In this paper we investigated automatic speed limit transmission based on RFID technologies. We conclude that both passive and active RFID systems show potential in such scenario, but are suitable for different scales of applications. For both technologies, challenges are identified and addressed, with system prototypes proposed and demonstration systems developed to prove the feasibility of our design concept

A possible hardware architecture of wireless sensor nodes

The paper focuses on the hardware architectures of wireless sensor nodes based on the IEEE 802.15.4/ZigBee protocol. It reviews the solutions provided by some main commonly used chip manufacturers, lists some of typical components and part of their parameters related to power consumption. The paper discusses the architecture of a canonical node and its subsystems, and analyzes the special requirements of wireless sensor nodes for building fire safety. A possible hardware architecture, centering routine transactions, of wireless sensor node, is presented

Connectionless indoor inventory tracking in Zigbee RFID sensor network

Abstract: Zigbee is one of the most exciting wireless sensor network (WSN) technologies for monitoring and control. In our previous research, an integrated Zigbee RFID sensor network was designed as an ‘all-in-one’ system solution for Humanitarian Logistics Center (HLC) resource management. Various field trials, which have justified the feasibility and features of such a system structure, have also revealed the requirement for simple yet reliable mobile tracking architecture for Zigbee network. In this paper a connectionless tracking architecture based on Zigbee RFID sensor network is proposed for inventory management applications. Such architecture features a consistent network structure, low hardware energy consumption and no accumulated error for localization algorithms with the least additional cost and hardware required on top of the existing Zigbee RFID sensor network systems. A simple demo system is also developed to demonstrate the feasibility of our design

Formal development of remote interfaces for large- scale real-time systems

The design of web-based user interfaces is of primary importance for achieving successful operation of Internet-based monitoring and control systems. Operators need to be able IO act promptly on changing situations requiring remote actions to process plants. A formal development process is proposed to determine the minimum amount of information that needs to be presented at interfaces. The first stage of the process is a specifcation of states of components that require operator actions. The main stage of the process uses model checking to generate interfaces with a minimal amount of information sufticient for the operator to perform all required actions. As well as improving the efficiency of operators, simpler interfaces allow for greater concurrency in the implementation of the remote operation of the process plant

A survey: localization and tracking mobile targets through wireless sensors network

Wireless sensor network applications have been deployed widely. Sensor networks involve sensor nodes which are very small in size. They are low in cost, and have a low battery life. Sensor nodes are capable of solving a variety of collaborative problems, such as, monitoring and surveillance. One of the critical components in wireless sensor networks is the localizing tracking sensor or mobile node. In this paper we will discuss the various location system techniques and categorize these techniques based on the communication between nodes into centralized and decentralized localization techniques. The tracking techniques are categorized into four main types. Each type will be compared and discussed in detail. We will suggest ways of implementing the techniques and finally carry out an evaluation

Priority checking RED for improving QoS in IPv6

This paper presents a priority checking random early detection (PC-RED) gateway for ensuring the quality of service (QoS) of high priority dataflow in IPv6 networks. A bit in the IP header is used in PC-RED to label the packet with the current status of the QoS that the dataflow is being treated in. The status of the QoS is determined by the difference between the packet average-dropping rate and the fixed desired limit dropping rate of the dataflow. PC-RED would perform dissimilarly to every dataflow corresponding to the different QoS status throughout congestions. PC-RED has been modeled and the parameter setting has been studied. Simulations of a TCP/IP network are used to illustrate how PC-RED affects the transfer of dataflow. The result shows remarkable contrast between the high-priority and non-priority dataflow throughput under PC- RED mechanism

PC-RED for IPv6: algorithm and performance analysis

This paper presents a Priority Checking Random Early Detection (PC-RED) gateway for ensuring the Quality of Service (QoS) of high priority dataflow in IPv6 networks. A bit in the IP header is used in PC-RED to label the current status of the QoS that the dataflow is being treated in, which is determined by the difference between the packet average-dropping rate and the fixed desired limit dropping rate of the dataflow. PC-RED would perform dissimilarly to every dataflow corresponding to the different QoS status throughout congestions. PC-RED has been modeled and the parameter setting has been studied. Simulation result shows remarkable contrast between the High-Priority and Non-Priority dataflow throughput under PC-RED mechanism