Partner Organizations:

Other collaborators:

We have established a collaboration with IBM T.J. Watson
Research (Dr. Xiaohui Gu and Dr. Dimitrios Pendarakis).
We have also established a collaboration with 
Nokia Research in Palo Alto, CA (Dr. Mielikainen and
Dr. Tuulos).
Through these collaborations we expect to have impact on 
real-life applications of the techniques we propose.

Activities and findings:

Research and Education Activities: 

The purpose of this research is to develop novel techniques to provide
in-network storage capabilities for sensor network architectures.
At the hardware level, our goal is to provide support, in the current
sensor architectures, for flash card memory. 
At the software level, our goal is to implement software components
that allows us to access and index the data stored in the flash. 
These components have to address the special characteristics 
and constraints of the flash memories. Individual sensors, 
equipped with external memory (such as flash memory), provide 
local storage and also contribute to building distributed storage
across the sensor system. Our goal is to build a large-scale storage
capability in the sensor network by combining the storage capabilities
of the flash cards of the individual sensors.
The broader impact of this work will be storage systems that
are efficient and easy to manage. The outcome of the proposed
work is expected to have significant impact on several disciplines
including, industry manufacturing, environment monitoring,
seismic and structural monitoring.
The educational component of the project seeks to promote early
student involvement in research and teaching, to develop a strong
curriculum, and to increase education awareness in sensor networks.

Findings:

We have developed new external memory index structures for the
efficient storage and retrieval of records stored on the local flash
memory of flash-based sensor network devices (TOS 2006), techniques
for compressing historical multidimensional sensor data (IJSN 2006)
and distributed techniques for reliable coverage restoration 
of sensor fields (IPDPS 2007). We have also presented new 
real-time traffic management techniques to support real-time 
flows in sensor networks (RTSS 2006), techniques for distributed
real-time detection and tracking of homogeneous regions (RTSS 2006)
and dynamic rate allocation techniques for distributed stream
processing systems to enable stream processing on data generated 
by sensors or other data sources (IPDPS 2007).
We have also developed techniques for internet-scale content search
and retrieval (TPDS 2007), improving the execution of large-scale
programs (IS, to appear) and approximate query processing in
peer-to-peer networks (TKDE 2007).

We have developed techniques for reliable real-time data collection
in sensor networks (GIS 2008). We have developed a distributed
cluster-based framework for congestion control and for supporting
multiple classes of traffic in sensor networks (TOSN 2008).
We have also presented new techniques for facilitating
congestion avoidance in sensor networks under the presence
of a mobile sink (RTSS 2007).
We have presented new techniques for predicting and alleviating
hot-spots in distributed stream processing systems (DSN 2008)
and for migrating components to different nodes in response
to overloads (DBISP2P 2008). We have also developed techniques
for dependable and QoS-aware distributed stream processing (ISORC 2008)
and replica placement techniques to provide high availability
to distributed stream processing applications (DEBS 2008).
We have also developed resource management mechanisms using
a multiple feedback loop structure in soft real-time distributed
object systems (JSS 2008).

We have developed a suite of index structures and algorithms on 
flash-equipped sensor devices which permit us to efficiently 
support real-time querying of historical data. Our techniques 
are designed to consider the unique read, write and wear 
constraints of the flash memories and the very limited data memory 
on the sensor devices; this allows us to efficiently retrieve 
historical data in real-time which has been considered in the past 
to be prohibitively expensive (RTSS 2008).
We have presented an online algorithm that attacks the problem of
placing relay nodes in a network of wireless sensor devices,
in regions where high localized congestion is detected.
Our algorithm can be efficiently utilized in situations where
immediate action is required, such as emergency response scenarios
where a high rate of packets are generated and data losses must
be minimized (SAINT 2008, Best Paper Award).
We have proposed techniques to address the problem of bursty
data streams in distributed stream processing systems
(IPDPS 2009, Best Paper Award).
Our approach consists of (i) an offline phase during which the
system proactively generates a number of possible rate allocation
assignments and (ii) an online phase where the system monitors the
resource usage and application behavior, and upon the onset of 
a burst, it uses the pre-calculated rate allocation plans to modify 
the input rates of individual components to accommodate the bursts
in a timely manner.
We have also studied the problems of data dissemination and query 
routing in a network that supports mobile devices (book chapter at 
Mobile Peer-to-Peer Computing for Next Generation Distributed 
Environments: Advancing Conceptual and Algorithmic Applications,
IGI Global, to appear) and proposed adaptive content-driven routing
and data dissemination algorithms for intelligently routing search
queries in a network with mobile users (STFSSD 2009).
We have proposed adaptive component composition and load balancing
mechanisms that satisfy the QoS of the applications and dynamically
adapt to changes in resource utilization availability and QoS
demands (PPNA, to appear) and sharing-aware component composition
techniques that allow us to discover and evaluate the reusability
of existing result streams, project the impact of instantiating
new stream applications on the execution times of the existing
streams to ensure that component reuse does not cause QoS violations
in existing stream applications (TPDS 2009).
We have also developed techniques for finding the K highest-ranked
answers in a distributed network (COMNET 2009) and a budget-based
self-optimized incentive search protocol that restricts selfish
user behaviors, lowers the search overhead while keeping high hit
rate (INFOCOM 2009).

Training and Development:

The project supports 5 graduate students. Song Lin earned his PhD
degree in 2007 and has joined Yahoo. Kyriakos Karenos earned 
his PhD degree in 2008 and has joined IBM T.J. Watson Research. 
Thomas Repantis completed his PhD degree in September 2008
and has joined Akamai Technologies.
Yannis Drougas earned his PhD in December 2008 and has joined ESRI.
Adam Dou is currently a PhD student. He is expected to complete
his PhD in the 2009-2010 academic year. 
The PI in the previous years has advised four undergraduate students,
Bilson Campana, Ricardo Perez, Mike Ballou and Roberto Rivas
who have worked on different aspects of the project. Currently,
the PI is advising one undergraduate student, David Slinger,
who is working on a data gathering component for the project.

Outreach Activities:

The PI was invited as a keynote speaker at the Databases, Information
Systems and Peer-to-Peer Computing Workshop (DBISP2P) in September 2006.

The PI received the Best Paper Award at the SAINT 2008 conference
(in Turku, Finland, July 2008), for her paper 'Dynamic relay node
placement in wireless sensor networks'.

The PI received a Best Paper Award at the 23rd IEEE IPDPS 2009 conference
(in Rome, Italy, May 2009), for her paper 
'Accommodating Bursts in Distributed Stream Processing Systems'.
IPDPS is one of the top conferences in distributed systems.

Journal Publications:

D. Zeinalipour-Yazti, V. Kalogeraki, D. Gunopulos, "pFusion: A P2P Architecture for Internet-Scale Content-Based Search and Retrieval", IEEE Transactions on Parallel and Distributed Systems (IEEE TPDS), vol. 18, (2007), p. 804., " " Published

Benjamin Arai, Gautam Das, Dimitrios Gunopulos, Vana Kalogeraki, "Efficient Approximate Query Processing in Peer-to-Peer Networks", IEEE Transactions on Knowledge and Data Engineering (IEEE TKDE), vol. 17, (2007), p. 919., " " Published

Sharmila Subramaniam, Vana Kalogeraki, Dimitrios Gunopulos, Fabio Casati, Umeshwar Dayal, Mehmet Sayal, Malu Castellanos, "Improving Business Process Models by Discovering Decision Points", Information Systems Journal, vol. 32, (2007), p. ., " " Published

Song Lin, Demetris Zeinalipour-Yazti, Vana Kalogeraki, Dimitrios Gunopulos, Walid Najjar, "Efficient Indexing Data Structures for Flash-Based Sensor Devices", ACM Transactions on Storage (ACM TOS), vol. 2, (2006), p. 468., " " Published

Song Lin, Vana Kalogeraki, Dimitrios Gunopulos, Stefano Lonardi, "Efficient Information Compression in Sensor Networks", International Journal of Sensor Networks, special issue on Wireless Ad Hoc and Sensor Networks, vol. 1, (2006), p. 229., " " Published

Yannis Drougas and Vana Kalogeraki, "RASC: Dynamic Rate Allocation for Distributed Stream Processing Applications", IEEE International Parallel & Distributed Processing Symposium (IPDPS 2007), vol. , (2007), p. 109., " " Published

Yannis Drougas and Vana Kalogeraki, "Distributed, Reliable Restoration Techniques using Wireless Sensor Devices", IEEE International Parallel & Distributed Processing Symposium (IPDPS 2007), vol. , (2007), p. 72., " " Published

Kyriakos Karenos and Vana Kalogeraki, "Real-time Traffic Management in Sensor Networks", 27th IEEE Real-Time Systems Symposium (RTSS 2006), vol. , (2006), p. 422., " " Published

Sharmila Subramaniam, Vana Kalogeraki and Themis Palpanas, "Distributed Real-Time Detection and Tracking of Homogeneous Regions in Sensor Networks", 27th IEEE Real-Time Systems Symposium (RTSS 2006), vol. , (2006), p. 401., " " Published

K. Karenos, V. Kalogeraki, S. Krishnamurthy, "Cluster-based Congestion Control for Sensor Networks", ACM Transactions on Sensor Networks (TOSN), vol. 4, (2008), p. ., " " Published

V. Kalogeraki, P. M. Melliar-Smith, L. E. Moser, Y. Drougas, "Resource Management Using Multiple Feedback Loops in Soft Real-Time Distributed Object Systems", Journal of Systems and Software, vol. 81, (2008), p. ., " " Published

V. Kalogeraki, A. Soheili, "Realiable Real-Time Data Collection", Encyclopedia of Geographical Information Science, vol. , (2008), p. 204., " " Published

Thomas Repantis and Vana Kalogeraki, "Alleviating Hot-Spots in Peer-to-Peer Stream Processing Environments", Fifth International Workshop on Databases, Information Systems and Peer-to-Peer Computing (DBISP2P 2007), Vienna, Austria, September 2007, vol. , (2007), p. ., " " Published

Kyriakos Karenos and Vana Kalogeraki, "Facilitating Congestion Avoidance in Sensor Networks with a Mobile Sink", 28th IEEE Real-Time Systems Symposium (RTSS 2007), Tucson, Arizona, December 2007, vol. , (2007), p. 3., " " Published

Vana Kalogeraki, Dimitrios Gunopulos, Ravi Sandu, Bhavani Thuraisingham, "QoS Aware Dependable Distributed Stream Processing", 11th IEEE International Symposium on Object- and Component-Oriented Real-Time Distributed Computing (ISORC 2008), Orlando, FL, May 2008, vol. , (2008), p. 69., " " Published

Jorge Mena and Vana Kalogeraki, "Dynamic Relay Node Placement in Wireless Sensor Networks", The 2008 International Symposium on Applications and the Internet (SAINT 2008) Turku, FINLAND, July - Aug 2008, vol. , (2008), p. ., " " Published

Thomas Repantis and Vana Kalogeraki, "Hot-Spot Prediction and Alleviation in Distributed Stream Processing Applications", The 38th Annual IEEE/IFIP International Conference on Dependable Systems and Networks (DSN 2008), Anchorage, Alaska, June 2008, vol. , (2008), p. ., " " Published

Thomas Repantis and Vana Kalogeraki, "Replica Placement for High Availability in Distributed Stream Processing Systems", The 2nd International Conference on Distributed Event-based Systems (DEBS 2008), Rome, Italy, July 2008, vol. , (2008), p. ., " " Published

S. Lin, B. Arai, D. Gunopulos, "Reliable Hierarchical Data Storage in Sensor Networks", 19th Int. Conference on Scientific and Statistical Database Management (SSDBM 2007), Banff, Canada, July 2007, vol. , (2007), p. 26., " " Published

A. J. Dou, V. Kalogeraki, "RG-EDF: An I/O Scheduling Policy for Flash Equipped Sensor Devices", 6th IFIP Workshop on Software Technologies for Future Embedded & Ubiquitous Systems (SEUS 2008), Capri Island, Italy, Oct 2008, vol. , (2008), p. ., " " Accepted

A. J. Dou, S. Lin, V. Kalogeraki, "Real-Time Querying of Historical Data in Flash-equipped Sensor Devices", The 29th IEEE Real-Time Systems Symposium (RTSS 2008), Barcelona, Spain, Nov-Dec 2008, vol. , (2008), p. ., " " Published

Dung Vu and Thomas Repantis and Vana Kalogeraki, "Efficient Data Dissemination in Overlays", First International Workshop on Software Technologies for Future Dependable Distributed Systems (STFSSD 2009), Tokyo, Japan, March 2009, vol. , (2009), p. ., " " Published

Yi Hu and Min Feng and Laxmi Bhuyan and Vana Kalogeraki, "Budget-Based Self-Optimized Incentive Search in Unstructured P2P Networks", INFOCOM 2009, Rio de Janeiro, Brazil, April 2009, vol. , (2009), p. ., " " Published

Yannis Drougas and Vana Kalogeraki, "Accommodating Bursts in Distributed Stream Processing Systems", 23rd IEEE International Parallel and Distributed Processing Symposium (IPDPS 2009), Rome, Italy, May 2009, vol. , (2009), p. ., " " Published

Thomas Repantis and Vana Kalogeraki, "Data Dissemination and Query Routing in Mobile Peer-to-Peer Networks", Mobile Peer-to-Peer Computing for Next Generation Distributed Environments: Advancing Conceptual and Algorithmic Applications, IGI Global Publishing, vol. , (2008), p. ., " " Accepted

Thomas Repantis, Yannis Drougas and Vana Kalogeraki, "Adaptive Component Composition and Load Balancing for Distributed Stream Processing Applications", Peer-to-Peer Networking and Applications, Springer, accepted, vol. , (2008), p. ., " " Accepted

Demetrios Zeinalipour-Yazti, Zografoula Vagena, Dimitrios Gunopulos, Vana Kalogeraki, Vassilis Tsotras, Michail Vlachos, Nick Koudas, Divesh Srivastava, "Finding the K Highest-Ranked Answers in a Distributed Network", Computer Networks (COMNET), Elsevier, Vol. 53, Issue 9, June 2009, vol. 53, (2009), p. 1431., " " Published

Thomas Repantis, Xiaohui Gu and Vana Kalogeraki, "QoS-Aware Shared Component Composition for Distributed Stream Processing Systems", IEEE Transactions on Parallel and Distributed Systems (IEEE TPDS), accepted., vol. , (2009), p. ., " " Accepted

Book(s) of other one-time publications(s):

Other Specific Products:


Internet Dissemination:

http://www.cs.ucr.edu/~vana/sensors0627191.html

Publications and other information related to the project will be published
at the project's web page as they become available.

Contributions:

Contributions within Discipline:

 The objective of this proposal is to develop new storage techniques
that will enable efficient flash memory support in sensor 
network architectures for long-term storage. Individual sensors,
equipped the flash memories, will provide local storage and also
contribute to building distributed storage across the sensor system.
Our techniques will address the special characteristics and
constraints of the flash memories and the energy constraints 
of the nodes. We will develop new techniques and the required 
data structures for inserting, deleting and indexing data stored
locally on the flash. We will design algorithms for supporting
equality, spatial and multi-dimensional queries in the sensor 
network. We will combine the index structures locally at the 
nodes to implement distributed storage. This will result 
in many Gigabytes of storage distributed across the system.