Monday, October 28, 2013

ACM MobiCom and MiSeNet 2013

On first week of October, I attended ACM MobiCom 2013 and one of its joint workshops, MiSeNet2013.  Prof. Olariu and I presented two papers at the MiSeNet workshop:  A Framework for Assessing the Quality of Event Detection in Sensor Networks and Toward Aggregating Time-Discounted Information. The later one won the best paper award of the workshop. In this paper, we mainly investigates the aggregation of information, where latency in aggregation leads to Value of Information (VoI) loss. The paper defines the algebra for the time-discounted aggregation of information. Based on this model, guidelines are developed for the design of aggregation mechanisms.

Prof. Olariu and Shahram are receiving the best paper award. From Left to right: Prof. Thomas F. La Porta, Prof. Stephan Olariu, Shahram Mohrehkesh, Dr. Habib M. Ammari
MobiCom, itself, had several interesting sessions and papers. I, personally, liked the Matt Welsh presentation, Why Mobile Performance is Hard. He mentioned about the need for understanding the interaction between applications and the network. One of the simple problem in this category is: Why does a video playback still stall even over a fast LTE network? The most interesting paper, probably, was Whole-Home Gesture Recognition Using Wireless Signals. The paper exploits the properties of wireless Doppler effect to identify gestures. Beside the novelty of model, it has the advantage that no additional sensing is required to be attached to human body. The method has 94% successful detection of gestures. Although there are several limitations ( users, and the need to repeat some gestures), it looks as a promising approach for further investigation.

This year MobiCom also featured a mobile application development contest for the first time. Since this was a new experience for participants and organizers, the quality of applications were not very outstanding. However, not only does this contest gave a new vibe to the conference, but also it introduced some creativity as well as research challenges.

In the poster section of conference, Mostafa Uddin and Dr. Nadeem presented SpyLoc: A Light Weight Localization System for Smartphones. The basic idea of the SpyLoc is to leverage the benefits of both the dead-reckoning and the ranging scheme to build a practical localization system. Given the high errors of the inertial sensors, SpyLoc uses a novel ranging scheme based on both the acoustic and WiFi interfaces to mitigate this error in order to improve the localization accuracy. Unlike the ranging-based or RF-based localization schemes that require multiple reference points (e.g., achor points), using the dead reckoning in SpyLoc reduces the required number of reference points to only one reference to locate and track users accurately.  In small scale experiment, SpyLoc has error less then 90cm for 90% of the times for different speed. These results proofs the feasibility and the efficiency of SpyLoc system under different mobility condition of the user.

Thursday, July 11, 2013

ALERT in Emergency Management Magazine

An article on our NSF-funded ALERT project will be included in the September 2013 issue of Emergency Management magazine.  Author Margaret Steen interviewed project PIs Michele Weigle, Stephan Olariu, and Jason Hallstrom (Clemson) for the article, titled "Researchers Retask Sensor Networks to Detect New Hazards".  An online version of the article is available now at

Thursday, June 6, 2013

First Green Communication and Networking Summer School

Last week, I attended the first summer school on Green Communication and Networking (GreenCommNet), May 28-31st, Boston, MA. It was organized by the PIs of the Genius (Green sEnsor Networks for aIr qUality Support) project. The focus of the school was to provide a background on research in green communication and networking as well as collaborative environment between faculty and students to discuss about future research.

The four-day summer school featured several talks from prominent experts in various areas of wireless communication, mobile computing and smart grid. Talks could roughly be divided in three categories: (I) state of art in energy harvesting devices and methods, (II) sensors and mobile application, and (III) smart grids.

Energy harvesting related talks started on first day with talk of Dr. Gil Zussman about his group's research on Energy- Harvesting Active Networked Tags (EnHANTs). The goal of EnHANTs project is to provide low consumption tags to be attached to several objects (books, toys, etc.) for localization applications. They have encountered several challenges during their work. First, they needed to know which of the energy sources could be useful for them. They measured energy harvesting that could be achieved by light, motion, etc. Based on their applications, they mainly focus on using indoor light to power up their tags. They also use Ultra Wide Band (UWB) as the communication mechanism among nodes. They also develop some methods to adapt the rate of transmission based on the rate of harvested energy. A brief description about their work could be found in this video clip.

The next talk about energy harvesting was about RF- based energy harvesting by Dr. Joshua Smith. There were two important results from their research. First, RF can be a significant source of energy, while most of previous research showed that energy harvesting from RF is not very efficient. However, they have built devices with about 40% harvesting reception efficiency. Second, most of their developed devices, which are based on their Wireless Identification and Sensing Platform (WiSP), only use capacitors for storing of harvested energy. For example, they develop accelerators and gyroscope device that only harvest UHF power and operate with no batteries.  One of the other projects among others that Dr. Smith talked about was Wireless Ambient Radio Power (WARP), which provides wireless energy for wireless devices over a long distance, e.g. 4 km. The amount of energy is not significant, but it can be useful for low power devices, such as sensor motes. The last talk about energy harvesting was by  Dr. Deepak Ganesan, titled passive communication for wireless sensors. The idea is to evaluate the scenario of communication thorough backscatter. However, since the amount of energy is limited, they are trying to develop schemes that could use this limited energy. They propose the idea of bit-bit communication, which tries to send several bits and after a period of sleep where it harvests energy, it will send some more bits. In this way, there are several challenges since the packets need to be assembled from disjoint bits. They name this mechanism as QuarkOS, which can enable communication with energy harvested from RFID communication. Though it is in its early stage, it has the potential to provide a communication with the minimum available energy.

There were three lectures related to application of sensor network and generally mobile computing. Prof. Sajal Das' talk was a review of his research over the last three decades. One of the most important part of his talk, among others, was cyber physical systems. He described the existence of two worlds that are now connected together. A network of devices that are human made such as PCs, laptops, cell phones, etc. On the other hand, through networks such as sensor networks and RFIDs,  many objects (traffic lights, books, parcels, etc) and other living beings (e.g. plant, animals) are now connected. Beside those networks, social networks, biological networks, etc. create an environment, which is composed of several networks in collaboration with each other. The idea of smart environment now is emerging with presence of this paradigm. In his opinion, future research would be an interdisciplinary one that will include psychology,  AI, machine learning, sociology, biology experts with networking experts in realizing an smart environment, that should have the minimum interference on human life.  Dr. Tommaso Melodia talked about their group research in the area of multimedia transfer over the wireless sensor networks. For a video surveillance application that camera sensor are responsible for transferring video to a central base stations, they try to minimize the energy for transmission of image as well as computation for encoding. They also encode the images in a new way 
 rather than regular encoding methods, such as MPEG or H.264 to increase the probability of image recoveries at decoder. The PIs of the Genius Project, Professors Wendi Heinzelman, Kaushik Chowdhury, Stefano Basagni, Swades De, and Soumya Jana talked about their air pollution monitoring application. After introducing the project by Dr. Kaushik Chowdhury, Prof. Wendi Heinzelman introduced their methods for saving energy of sensor motes through radio wake-up, in which nodes wake up from sleep mode through a radio signal. They extend the range of wake up with designing a low consumption wake-up circuit. Through this method, they increase the wake-up range up to 45 ft. The Genius presentation continued with the work of their Indian partners. Dr. Swades De presented his efforts for the goal of providing multi-hop wireless charging. The effort is to extend the range of wireless charging of sensor nodes through several layers. In spite of typical wireless charging, where a transmitter charges some node, in their method these nodes will charge nodes farther from the main charger. Finally Dr. Soumya presented their ideas about creating the pollution map and health risk map from collected sensor data.  

Third category of talks belonged to smart grid, which included three talks. Mr. Ashish Shah, from Analog Devices company talked about  smart grid the state-of-art . The role of ICT sector in collaboration with government and utility companies for realization of smart grid has created a complex paradigm. The lack of specific allocated spectrum makes the challenges of creating the smart meter devices as the first step of smart grid development more difficult. A low cost, low power and reliable communication mechanism is required for smart meters as well as other elements in a smart grid. Economic aspects for consumers as well as companies increase the already complex situation of billion node smart grid more challenging.  He presented some of methodologies that their company used to cope these challenges in designing  RF chips for smart grid. As the last talk, Prof. Jim Kurose talked about the possible areas that networking experts can help at the development of smart grid. Specifically, he mentioned about experiences in areas such routing of flows and congestion problem that could be used to solve the similar problems in smart grid.  

In summary, I found this summer school a unique experience, which provided me with a rich background in several topics of green communication and networking. I would like to thank the organizers of the Genius project, especially Professors Wendi HeinzelmanKaushik Chowdhury and Stefano Basagni for hosting this event. 

Wednesday, April 24, 2013

Congratulations, Dr. Mohammad Almalag!

Mohammad successfully defended his PhD dissertation, "TDMA Slot Reservation in Cluster-Based VANETs", under the supervision of Dr. Michele C. Weigle on April 3, 2013.

Mohammad was a top-ranked student in the field of computer science at the Computer and Information Systems College. He received his Bachelor’s Degree in Computer Science from King Saud University in 2000. In Spring 2001, he joined the Department of Computer Science and Information System at Imam University as a teacher. In Fall 2002, Mohammad joined the master’s program in the Department of Computer Science at Ball State University. He received his Master’s Degree in Computer Science in Fall 2004.

Mohammad joined the PhD program in the Department of Computer Science at Old Dominion University in Fall 2005. In 2008, he started his research under the supervision of Dr. Michele C. Weigle. Mohammad had been active in the areas of wireless networks, sensor networks, vehicular networks, MAC layer protocols, and networks simulation. With interest in MAC layer protocols and vehicular networks, Mohammad’s PhD focus, including his dissertation, was on developing a new MAC protocol for vehicular ad-hoc networks. Specifically, his focus was on improving the non-safety application share of the bandwidth.

Mohammad's defense slides are below:

Wednesday, December 5, 2012

NSF BioCom2 Workshop

On November 8-9, 2012, I attended the NSF Workshop on Biological Computations and Communications (BioCom2) in Boston.  The workshop was focused on bringing in researchers from different areas (computer science, bioengineering, physics) to discuss recent work and issues in computation and communication in the bio-nano world. There were several great talks, mostly focusing on communications issues in biological networks.

(I was nervous about traveling to Boston in November, and sure enough, it snowed.)

I presented work that PhD student Shahram Mohrehkesh and I are investigating on nanosensor networks (slides are below).  We are just beginning our study, so much of the talk covers previous work done by Georgia Tech in their GRANET project (Jornet and Akyildiz).

Communications and Energy-Harvesting in Nanosensor Networks from Michele Weigle

Here's a snippet of the write-up we submitted to the workshop:

Nanosensor Networks: The development of nanoscale sensor networks, or nanosensor networks, has been inspired by biological nanoscale networks. These nanosensor networks could be used detect chemical compounds in concentrations as low as one part per billion or the presence of different infectious agents such as viruses or harmful bacteria. These networks are composed of thousands of nanoscale nodes. Communication among these nodes and with the external world is an exciting new topic in networking. So far, two methods of communication have been proposed for these nanosensors: molecular communication and electromagnetic communication. Because of the limitations in molecular communication, mainly its low speed, our focus is on electromagnetic communication.

Communications and Energy-Harvesting: Pulse-based communications in the Terahertz band has been proposed as the communications method for these nanosensors [1]. Because of this, new medium access protocols must be developed as existing ones for carrier-sensing based systems are not applicable. One advantage to using short pulses for communication in a high bandwidth channel is that the probability of collision of the pulses is very small.

One challenging issue is that these nodes will have relatively small power supplies (and computation engines) due to their nanoscale. It has been estimated that the maximum capacity of a nano battery would be on the order of 800 pJ and that the transmission of a single short pulse will expend 1 pJ of energy [2]. If we map a pulse to a single bit, then a nanosensor can send at most an 800-bit packet before needing to harvest energy. Using vibration for energy-harvesting, this could take on the order of seconds (50 sec from vibrations from an A/C vent) to minutes (42 min from human heartbeat) [2].

Because of the long duration of energy-harvesting, multi-hop communication becomes an issue. For a nanosensor to successfully deliver a packet to a data sink, at least some neighboring nodes must be awake and have sufficient power to receive the message and forward it. If there are no awake neighbors, then the packet may need to be retransmitted later, wasting precious energy and reducing the quality of service in terms of delay and throughput. So, energy harvesting-aware protocols for communication among nanosensors are required. In addition, the stochastic behavior of the energy-harvesting sources should be taken into account, as some sources such as thermoelectric or RF may not be available all the time.

We are interested in developing intelligent, energy-harvesting aware scheduling strategies for communications between nanosensors. To do this, we are modeling the energy usage of communicating nanosensors. We are also building upon previous research to develop efficient pulse-based encoding schemes that can use silence as well as pulses for communication, thus saving energy. On top of this, we will develop a medium access protocol using repetition and retransmission for data delivery with an acceptable rate of reliability.

[1] I. Akyildiz, J. M. Jornet, Electromagnetic wireless nanosensor networks, Nano Communications Networks, vol. 1, no. 1, pp. 3-19, March 2010.
[2] J. M. Jornet and I. Akyildiz. Joint Energy Harvesting and Communication Analysis for Perpetual Wireless NanoSensor Networks in the Terahertz Band, IEEE Trans. Nanotechnol., vol. 11, pp. 570-580, May 2012.

Thursday, August 2, 2012

Congratulations, Dr. Samy El-Tawab!

Samy successfully defended his PhD dissertation, “FRIEND: A Cyber-Physical System for Traffic Flow Related Information Aggregation and Dissemination”, under the supervision of Dr. Stephan Olariu on July 27th, 2012.

Samy received his Bachelor’s Degree in Computer Science with honors from Faculty of Engineering, Alexandria University in 2002. In 2006, he received the Master Degree in Computer Science from Alexandria University. Samy Master’s thesis, “Redundant Traffic Encoding in VoIP Systems”, was focused on enhancing the quality of voice and solving the problems of delay, packet-loss or jitter.

Samy joined the PhD program in the Department of Computer Science at Old Dominion University in fall 2006. In spring 2009, Samy got a prize for excellence in scholarship at The College of William and Mary’s 8th annual graduate research symposium, Williamsburg, Virginia, USA. In 2010, he received the outstanding teaching assistant award given by College of Science for his excellent teaching and continuing good work in the spring 2010 semester.

Samy’s research interests include a wide variety of interesting vehicular networks related topics such as incident detection, efficient data dissemination, security, privacy, and cloud computing. His research work and ideas were well received by the VANET research community, with publications in various journals, conferences and workshops.

Samy’s defense slides are below:

Monday, July 2, 2012

The Thirteenth International Symposium on a World of Wireless, Mobile and Multimedia Networks (WoWMoM 2012)

On Sunday June 24th, 2012; Mohamed Almalag and I started our trip to the 13th IEEE International Symposium on a World of Wireless, Mobile and Multimedia Networks, WoWMoM 2012, which took place this year in San Francisco, California, USA. On Monday, June 25th, 2012, we presented our papers FRIEND: A Cyber-physical System for Traffic Flow Related Information aggrEgatioN and Dissemination” and “TDMA Cluster-based MAC for VANETs (TC-MAC) in the VTP workshop (VANETs from Theory to practice).

Samy El-Tawab presenting his paper : FRIEND: A Cyber-physical System for Traffic Flow Related Information aggrEgatioN and Dissemination

Mohammad Almalag presenting his paper: TDMA Cluster-based MAC for VANETs (TC-MAC)

The VTP workshop started with a keynote speaker Dr. Marco Fiore who gave a great presentation title “Back to basics: road traffic in vehicular networking”. Dr. Fiore talked about the importance of mobility in vehicular networking. Dr. Fiore gave a short history of how vehicular mobility is modeled going through three components: the road topology and infrastructure information, then vehicular mobility model and ending with traffic flow model.

Dr. Fiore discussed road topology from early work of regular grid (as known as Manhattan layout) and manually defined layout to increasing the layout realism. When talking about the second component which is the vehicular mobility model, he described the macroscopic model, the mesoscopic model and microscopic model. When talking about the microscopic model in vehicular mobility, he explained the different classifications: the traffic stream, the stochastic, car following and the flows-interactions giving some examples on each one of it. Dr. Fiore, then talked about the vehicular mobility simulation tools with each one features and problems.

When talking about the third component "traffic flow models", he mentioned that these aspects are neglected by the vast majority of the networking community and it is very important to study the impact of it. Dr. Fiore closed his talk with a look into the future of vehicular networking such as "a unified test dataset", " a realistic / dedicated RF signal propagation " and " an improved vehicular mobility representation ". After couple of questions asked by the audience, the presenters started.

At the end of the workshop, we took a picture with other presenters. For more info about the VTP 2012 workshop program please visit: VTP 2012 workshop website.
On the 26th to 28th of June, 2012; we attended the main WoWMoM conference sessions. It was a great experience, and we were introduced to high quality research through the presentations. On the 26 June, Professor Ruzena Bajcsy from University of California, Berkeley, Department of Electrical Engineering and Computer Sciences (EECS) gave a keynote titled "Monitoring and Coaching Elderly People to Exercise at Home" and on the 27 of June, Dr. Ravi Jain from Google, Inc gave a keynote title "Mobile Advertising, Data and Networks ". Dr. Jain who is the director for mobile search advertising at Google, Mountain View, California was asked couple of questions concerning the security and privacy of the mobile users. For more info about the WoWMoM 2012 conference technical program please visit : WoWMoM 2012 technical program website.