39 research outputs found

    A wireless system for crack monitoring in concrete structures

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    The formation of cracks in concrete is a normal phenomenon. However, effective control and prevention of the formation of cracks is the key for successful life of concrete structures. Specifically, cracks represent a path of least resistance for moisture and corrosive ionic agents from de-icing salts to reach embedded steel in concrete. Commercial wireless sensor networks utilizing crack gauge sensors can be applied for crack monitoring in the common concrete structure. The crack sensors circuits\u27 boards, which are used to stimulate the cracks, are currently unavailable for the SG-Link module platform. The SG-Link module is an ultra-low-power module for use in sensor networks, monitoring applications and rapid application prototyping. Therefore, a crack sensor circuit board for the SG-Link module platform has been developed. The development of a smart wireless sensor network for the crack monitoring system is divided into four parts: a crack gauge sensor, signal conditioning, the SG-Link module, and a base station unit. The signal conditioning module consists of a crack gauge sensor, a wheatstone bridge, an amplifier, and a filter. The SG-Link module consists of an analog to digital converter (ADC), a microcontroller unit (MCC), and a transmitter with an antenna. The base station unit includes an antenna and a receiver module connected to the base station or computer. In this study, cracks are monitored based on the change of the electrical resistance between the sensor\u27s two terminals that are taken from the simulation model of the crack sensor board consisting of a crack gauge sensor and signal conditioning. This thesis looked at the effectiveness of a wireless system for crack monitoring in concrete structures. Tests were conducted in a laboratory to monitor the cracks in the structures and explore the validity and reliability of the monitoring mechanism and data transmission

    PACKET ERROR RATE PREDICTIVE MODEL FOR SENSOR RADIOS ON FAST ROTATING STRUCTURES

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    Wireless sensing technologies have raised widespread interests in the applications for monitoring fast rotating or moving machinery structures in manufacturing environments. Over the past five years, a few wireless sensor systems have been implemented and proven to feasibly work under fast rotation conditions. However, few of these studies evaluated data transmission performance of the wireless communication systems. Although the manufacturing environments are known to be harsh for wireless communication, in many cases, an excellent data throughput is critical for such systems. Conventional statistical methods for studying wireless communication channels are not sufficient in this specific field. This dissertation presents systematic experiments to understand and characterize the behavior of a 2.4 GHz band wireless channel between a fast rotating transmitter and a stationary data receiver. The experiments prove, in manufacturing machines, multipath propagation induced by metallic objects causes high power attenuation of radio signals during transmitter motion, and the consequence, low received signal power, is recognized as the major cause of transmission errors. The dissertation proposes a deterministic packet error rate (PER) predictive model for rotating wireless measuring systems using IEEE 802.15.4 sensor radios. The model consists of three sub-models that predict power attenuation, bit error rate (BER), and PER in three stages for given specifications regarding environment, radio transmission, and rotation. The dissertation provides experimental validation of the sub-models and discusses their limitations and prediction errors. By either experiments or simulations, two data transmission protocols, automatic retransmission request (ARQ) method and online error avoidance algorithm, are proved efficient for a reliable wireless communication of such sensor radios. As the first effort to characterize and model such radio channels, the dissertation provides in-depth understandings of the channels\u27 fast varying behavior, achieves prediction guidance for the channels\u27 communication performance, and introduces prospective transmission protocols for performance enhancement

    DESIGN OF RELIABLE AND SUSTAINABLE WIRELESS SENSOR NETWORKS: CHALLENGES, PROTOCOLS AND CASE STUDIES

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    Integrated with the function of sensing, processing, and wireless communication, wireless sensors are attracting strong interest for a variety of monitoring and control applications. Wireless sensor networks (WSNs) have been deployed for industrial and remote monitoring purposes. As energy shortage is a worldwide problem, more attention has been placed on incorporating energy harvesting devices in WSNs. The main objective of this research is to systematically study the design principles and technical approaches to address three key challenges in designing reliable and sustainable WSNs; namely, communication reliability, operation with extremely low and dynamic power sources, and multi-tier network architecture. Mathematical throughput models, sustainable WSN communication strategies, and multi-tier network architecture are studied in this research to address these challenges, leading to protocols for reliable communication, energy-efficient operation, and network planning for specific application requirements. To account for realistic operating conditions, the study has implemented three distinct WSN testbeds: a WSN attached to the high-speed rotating spindle of a turning lathe, a WSN powered by a microbial fuel cell based energy harvesting system, and a WSN with a multi-tier network architecture. With each testbed, models and protocols are extracted, verified and analyzed. Extensive research has studied low power WSNs and energy harvesting capabilities. Despite these efforts, some important questions have not been well understood. This dissertation addresses the following three dimensions of the challenge. First, for reliable communication protocol design, mathematical throughput or energy efficiency estimation models are essential, yet have not been investigated accounting for specific application environment characteristics and requirements. Second, for WSNs with energy harvesting power sources, most current networking protocols do not work efficiently with the systems considered in this dissertation, such as those powered by extremely low and dynamic energy sources. Third, for multi-tier wireless network system design, routing protocols that are adaptive to real-world network conditions have not been studied. This dissertation focuses on these questions and explores experimentally derived mathematical models for designing protocols to meet specific application requirements. The main contributions of this research are 1) for industrial wireless sensor systems with fast-changing but repetitive mobile conditions, understand the performance and optimal choice of reliable wireless sensor data transmission methods, 2) for ultra-low energy harvesting wireless sensor devices, design an energy neutral communication protocol, and 3) for distributed rural wireless sensor systems, understand the efficiency of realistic routing in a multi-tier wireless network. Altogether, knowledge derived from study of the systems, models, and protocols in this work fuels the establishment of a useful framework for designing future WSNs

    Employing RFID for an Equipment Management System via Wireless Sensor Network

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    This paper is mainly in combination with RFID to construct a set of power system equipment remote control, used first on the reader tags received after the use of Visual Basic in order to determine the signal and then transmits the signal via the RS232 cable to control circuit 8051 to control the instrument power switch. The topic is written in the Visual Basic RFID and uses features, such as personnel control systems, and access control systems, which are derived from the time of access control systems, several instrument control systems, and uses records stored in the form of functions, where the other circuit transmits signals to Visual Basic 8051, and then, by 8051, controls the instrument power switch

    Phase Space Dissimilarity Measures for Structural Health Monitoring

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    Protocols for alternative sexuality and sensibility

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    Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2006.Includes bibliographical references (p. 95-97).It is often said that we live in a network society. Increased familiarity with technical networks has brought the concept to the forefront of public imagination making the network a dominant trope. Whether inherent or ascribed, topologies seem to appear in social theories, transportation systems, technological structures and biological systems to name only a few examples. Often descriptions of networks combine semantics reflecting both conceptual and physical meaning. Regardless of content, be it conceptualization of power, information between computers, relationships between people or neurons; networks rely on topologies and protocols that locate nodes in relation to one another. In the field of technology certain networks are apparent - the internet and the world wide web constitute easily identifiable examples. In the social sciences, descriptions of relationships between people and even of self identity lend nicely to nodes, edges, curves and vertices. In the blurring of boundaries between disciplines the language of the network also becomes a node of interconnection. Technology, sociology, and various branches of theory reference each other in a search for deeper meaning within disciplines.(cont.) Protocols for Alternative Sexuality and Sensibility or PASS is a wireless networked system designed to function with a multidisciplinary description of a network in mind, incorporating conceptual implications and technical implementation of networking. PASS is a system which visibly tracks connections in public space based on the embodiment of protocols associated with sexual identity. These user configured devices exchange information with other devices in order to uncover the often hidden interconnections created by the internalization of sexual identity. Sexual identity is represented by several alternative paradigms in addition to the culturally predicated homosexual/heterosexual binary. The resulting connections are made visible via independent graphical displays that indicate the various paradigms and connections at play. PASS shows how dominant cultural networks necessitate counter spaces which exist simultaneously in time and space with the hegemonic structures. It is in the revealing of these alternative spaces that I seek a technology of resistance; by connecting people in these counter spaces we create dynamic modes for understanding the influence of normativity and the experience of otherness. The physical representation of these theories reveal the hegemonic protocol structures of interconnection which we internalize as social norms.by Gemma Shusterman.S.M

    Real Time Gas Monitoring System Using Wireless Sensor Network

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    Miner’s safety is the main issue in the present era. Miner’s health is affected by many means which includes unstable and cumbersome underground activities and awkward loads, heavy tools and equipment, exposure to toxic dust and chemicals, gas or dust explosions, improper use of explosives, gas intoxications, collapsing of mine structures, electrical burn, fires, flooding, rock falls from roofs and side walls workers stumbling/slipping/falling, or errors from malfunctioning or improperly used mining equipment. In earlier days for detection of gases canary and small animals are used but they didn’t provide the exact condition of the mines so safety in the mine in not guaranteed. Hence, there is a need of monitoring system which utilised the ZigBee wireless sensor network technology. There are two units of the monitoring system Sensor unit and Monitoring unit. Sensor unit will be placed in the underground section and Monitoring unit will be placed in the above the mines from where monitoring is done. Firstly, the Sensor unit is placed in the underground section of the mine. Where input is taken from the sensors in terms of Methane (CH4) i.e. MQ-2 sensor, Hydrogen Sulphide (H2S) i.e. MQ-136 sensor, and Natural Gases i.e. MQ-5 sensor. Then they are compared with their threshold value by the Microcontroller Module and if the value is above the threshold value, the Buzzer starts ringing meanwhile data is displayed in the Display module and sent to the Wireless Communication Module of the Monitor unit i.e. ends device or coordinator through the Wireless Communication Module of the Sensor unit i.e. router. In this way, the study can help the miners get relief from any casualty and ultimately save their lives. The device encompasses a large range of networking. The data can also be stored for future investigation. The device is also durable and costs effective with a price of approx. Rs. 6,500 to 7,000/-

    Routing algorithms for wireless sensor : networks based on the duty cycle of its components

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    [eng] Wireless sensor network is one of the most important topics in the current data transferring. In fact regarding to data gathering and transformation, cost effective is the top topic and optimum point, which every vendors and sector are focusing on it. In the field of petrochemical regarding sensitive processes could not stay out of this scope and start to monitor the gas pipes and processes over the wireless fashion. Therefore some items should have been taking into considerations such as: instant monitoring, nonstop characteristic, long term investing and energy consuming. According to those aforesaid items, we have planned to do an investigation and find the feasibly of how we can to create and distribute a network to have accuracy to measurement , sending data reliability, having long term network life cycle and having minimum energy consuming. Therefore the only technology could help us was IEEE 802.15.4 with mixed of microcontrollers and transceivers, able to manipulate to reach out our objects in maximizing lifetime and minimizing latency in wsn, as an unique routing algorithm in Mobile ad Hoc Network. WSN in fact is a relatively new section of networking technology and nowadays is more popular. The reason of these advantages instead of others is low-power microcontroller and inexpensive sensor usage for any communications and also simple sensor designing. Regarding to network layers, Physical layer for WSN based on IEEE802.15.4 is fundamental of frames and packets transactions. So two main devices which are involving in this project: transceivers such as CC2520 and CC3200 ZigBee/IEEE 802.15.4 RF, managed by microcontrollers. Common controller for those transceivers such as MSP430F1611 16-bit MSP430 family for Texas instrument in the nodes and coordinators ideas were selected. One step more close to the idea, was other layer so called Link layer or in other hand MAC layer. Another advantage of WSN is ability to manipulate MAC layer, because modifications in lower layer always has low Energy consuming than other layers. Therefore according to these circumstances, MAC protocols are able to energy efficiency, also reduce and achieve to zero based of unused time in WSN. So any WSN, energy wasting could be control in MAC sub layer and even though MAC protocols. Other layer in WSN is declared as a Network layer, the logical way which those packets could be find the best way and shortest path in minimum time as possible and reachability to the main point based on node and coordinator. Nodes are programmed in upper layer and have been matched with MAC layer, now it's time to join and stick the frames in a packet and involving to each other. Meanwhile we decided to create a middle layer through MAC and Network layer to play as a bridge, mainly called VRT (Variable Response Time) and FRT (Fixed Response Time) to control the energy consumption in the process of routing in network layer. This algorithm is cooperating with MAC layer in sleep and wake up modes, in fact with VRT, nodes just received their needs and captured the vital packet in wake up mode, sends back the answer, now the task is finished and both sided transaction is done. After that, it's not need to have more listening and capturing packets from the remote nodes as a coordinator therefore, left the transmission process to save more energy for further wireless communication stream in sleep mode. Also FRT is another algorithm in MAC layer, to decrease the energy consumption. This algorithm is switch based energy control, as a same concept in VRT in sleeping and wakeup mode. Finally we have design this algorithm in Simulator and real world. The results correlate quite well results showing as a good agreement between two worlds, also we have obtained better results in battery consumption over network life cycle to other business algorithms.[spa] En este trabajo nos focalizaremos en la minimización del consumo a partir de la minimización del número de transmisiones. Buscamos por tanto aquel algoritmo que nos permita aumentar la probabilidad de aciertos. Esta idea, diseñará el algoritmo de enrutamiento que mejor se ajusta a la red MANET. Una vez simulada la red se diseñará un "testbed" en donde una parte de la red se implementará de forma real, mediante la introducción de sensores inalámbricos y la otra parte se hará de forma simulada, a través de una interfaz que interconecta el mundo real con la simulación de Spyder. Se pretende ver que ambos mundos progresan de forma similar. Con respecto a la capa de OSI en WSN, sería prioritaria la capa física o capa de hardware, por este motivo nuestra proyecto también se centra en el tipo determinado de hardware que debe aplicarse para obtener resultados satisfactorios. Entonces tratamos las características de los dos hardwares, el transceiver y el microcontroller. También se trata en este apartado su concepto lógico de acuerdo con la ficha técnica oficial IEEE802.15.4. La segunda prioridad de la capa OSI se centra en el Medium Access Control (MAC) de la capa. En esta capa nuestro objetivo se logrará mediante la manipulación de las addresses MAC. Los protocolos MAC deben estar orientados a la reducción del consumo de energía y también a la reducción del tiempo no utilizado en WSN, para ello aplicamos algunas políticas para controlar los comportamientos del tráfico en esta capa para cambiar el consumo de energía, la vida útil de la red y evitar el gasto innecesario de recursos, en realidad concentramos a nuestro algoritmo VRT y FRT. Respecto de la idea principal, de controlar los sensores para aumentar la vida útil de la red y disminuir el consumo de energía. En realidad se explica cómo controlar la capa MAC y forzar el hardware para lograr el objetivo principal de este proyecto. De hecho podemos decir que mejoramos el reenvío de paquetes entre los sensores intermedios, buscando el promedio de distancia HOP más corta desde el origen al destino, así como la disminución del consumo de energía en cada sensor
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