http://www.eecs.ucf.edu/~dcm/Teaching/COT4810-Spring2011/Literature/SensorNetworksSurvey.pdf

Wireless sensor networks: a survey

http://www.csun.edu/~andrzej/COMP529-S05/papers/Mesh%20Networks%20Survey.pdf

Wireless mesh networks: a survey

In the last years, wireless sensor networks (WSNs) have gained increasing attention from both the research community and actual users. As sensor nodes are generally battery-powered devices, the critical aspects to face concern how to reduce the energy consumption of nodes, so that the network lifetime can be extended to reasonable times. In this paper we first break down the energy consumption for the components of a typical sensor node, and discuss the main directions to energy conservation in WSNs. Then, we present a systematic and comprehensive taxonomy of the energy conservation schemes, which are subsequently discussed in depth. Special attention has been devoted to promising solutions which have not yet obtained a wide attention in the literature, such as techniques for energy efficient data acquisition. Finally we conclude the paper with insights for research directions about energy conservation in WSNs.

/pdf/energy-conservation-in-wireless-sensor-networks-a-survey-1bl7d2obnm.pdf

Energy conservation in wireless sensor networks: A survey

The objective of this paper is to give a comprehensive introduction to applied cryptography with an engineer or computer scientist in mind. The emphasis is on the knowledge needed to create practical systems which supports integrity, confidentiality, or authenticity. Topics covered includes an introduction to the concepts in cryptography, attacks against cryptographic systems, key use and handling, random bit generation, encryption modes, and message authentication codes. Recommendations on algorithms and further reading is given in the end of the paper. This paper should make the reader able to build, understand and evaluate system descriptions and designs based on the cryptographic components described in the paper.

[서평]「Applied Cryptography」

Energy harvesting generators are attractive as inexhaustible replacements for batteries in low-power wireless electronic devices and have received increasing research interest in recent years. Ambient motion is one of the main sources of energy for harvesting, and a wide range of motion-powered energy harvesters have been proposed or demonstrated, particularly at the microscale. This paper reviews the principles and state-of-art in motion-driven miniature energy harvesters and discusses trends, suitable applications, and possible future developments.

/pdf/energy-harvesting-from-human-and-machine-motion-for-wireless-3lsf4oudvo.pdf

Energy Harvesting From Human and Machine Motion for Wireless Electronic Devices

To address the demands for more capacity and higher data rates, the fifth generation network (5G) technology is being developed and gradually rolled out by major cellular carriers. Millimeter wave (mmWave) systems and unmanned aerial vehicles (UAVs) are two critical enablers of 5G. To ease the integration of 5G into existing networks, it is essential to study how base stations (BSs) can be used to serve both ground and aerial users simultaneously in a mmWave network. In this work, we consider BSs equipped with two antennas- one tilted down to serve ground users and another tilted up to serve aerial users. Using ray tracing simulations, we investigate the ideal tilt of these two antennas. Our results indicate that reusing the spectrum effectively in urban environments requires an understanding of the interplay between the effects of shadowing due to buildings, ground reflections, beam orientation, BS separation, interference between the two beams, and UAV heights. Specifically, to simultaneously serve UAVs at a height of 200 m and ground users, it is desirable to use a BS equipped with one antenna tilted up at 30 degrees and another tilted down at of 10 degrees. This achieves the best compromise between the above effects for the simulation configuration considered in this paper. Further, it was observed that the aerial and ground users are, in some scenarios, actually better served by the antenna not meant for them.

Spectrum Reuse among Aerial and Ground Users in mmWave Cellular Networks in Urban Settings

This document describes the development of a structural health monitoring system using wireless sensor nodes equipped with strain gauges and its validation. Each node consists of a sensor (strain gauge), a signal conditioning circuit and a mote. Several such nodes can be monitored and controlled by a base station. The system measures strain in the structural element, converts it to an analog voltage signal, amplifies and filters the analog signal, converts it to a digital signal, processes and, finally, transmits it using wireless links. Each of the building blocks of the system, its functions, design considerations and specifications are described in this report.

Wireless structural health monitoring system design, implementation and validation

The subject of controlling an integrator via a communication network finds many applications in modern control systems. Stability conditions in closed form are derived for the arising feedback system, which consists of a controller, an integrator and time-variant links between integrator and controller. It will be shown, that these derived stability conditions are not conservative and easily applicable, even for systems with long delays. In order to draw from a recent result on time-variant discrete system stability, FIR controllers are assumed.

Controlling an integrator through data networks: stability in the presence of unknown time-variant delays

Multihop relaying in WiMAX networks is considered a cost effective way to extend the coverage of the base stations, increase cell capacity, or both. In this paper, we consider deploying non-transparent relay stations for coverage extension and study the issue of fairness schemes in such networks. Since there are access and relay zones in both downlink and uplink frames and simultaneous transmissions are possible in the access zone, it is challenging to schedule resources optimally for serving subscriber stations in a fair manner. We evaluate the performance of well known fairness schemes such as max-min and proportional fairness in such networks. We also propose a new scheduling scheme, named subsection fairness that can achieve better throughput than traditional fairness schemes by maximizing bandwidth utilization. Our numerical results evaluate the performance of each scheduling scheme in terms of cell throughput and fairness.

Fairness Schemes in 802.16j Mobile Multihop Relay Networks

A new, more realistic model for the ABR traffic class in ATM network congestion control is introduced and analyzed. The new discrete time model takes into account the effect of time-variant buffer occupancy levels of ATM switches, thus treating the case of time-variant delays between a single congested node and the connected sources. For highly dynamic situations, such a model is crucial for a valid analysis of the resulting feedback system. The new model also handles the effects of the mismatch between the RM cell rates and the variable bit rate controller sampling rate as well as buffer and rate nonlinearities. A stability study is presented, that shows an equilibrium in the buffer occupancy level is not possible if time-variant delays are present in the forward path. Stability conditions for the case of time-variant delays in the return path axe derived. Finally, illustrating examples are provided.

Mihail L. Sichitiu

Papers

Spectrum Reuse among Aerial and Ground Users in mmWave Cellular Networks in Urban Settings

Wireless structural health monitoring system design, implementation and validation

Controlling an integrator through data networks: stability in the presence of unknown time-variant delays

Fairness Schemes in 802.16j Mobile Multihop Relay Networks

The effect of uncertain time variant delays in ATM networks with explicit rate feedback