- Next Generation Network Measurement Infrastructures (NG-NMIs)
- Project Description
- People
- Chang-Gun Lee and Prasad Calyam
- Publications
- P. Calyam and C.-G. Lee, Characterizing Voice and Video Traffic Behavior over the Internet, Submitted to Computer Communications Journal, 2004
- P. Calyam, C.-G. Lee, D. Xuan, and D. Lee, Effects of Human, End-Point, and Network Factors on Interactive Multimedia Internet Traffic, Submitted to SIGMETRICS 2005
- Outside Website
- System-wide resource management for complex real-time systems
- Project Description
- People
- Chang-Gun Lee and Sang Gook Han
- Publications
- D. Thomas, S. Gopalakrishnan, M. Caccamo, and C.-G. Lee, Spare CASH: Reclaiming Holes to Minimize Aperiodic Response Times in a Firm Real-Time Environment, Submitted to EUROMICRO Real-Time Systems 2005
- C.-G. Lee, A Novel Framework for QoS-aware Resource Management in Phased Array Radar Systems, to appear RTAS 2005
- S. Gopalakrishnan, M Caccamo, C.-S. Shih, C.-G. Lee, and L. Sha, Finite-Horizon Scheduling of Radar Dwells with Online Template Construction, Proceedings of RTSS 2004, (Best Student Paper Award)
- C.-G. Lee, P.-S. Kang, C.-S. Shih, M. Caccamo, and L. Sha, Schedulability Envelope for Real-Time Radar Dwell Scheduling and Its Application to Multi-Ship Multi-Radar Systems, Proceedings of Radar 2004 International Conference, Toulouse, France, Oct. 2004
- C.-S. Shih, M. Caccamo, L. Sha, and C.-G. Lee, Radar Dwell Scheduling with Temporal Distance and Energy Constraints, Proceedings of Radar 2004 International Conference, Toulouse, France, Oct. 2004
- P.-S. Kang and C.-G. Lee, Coordinated Search and Track by Multiple Phased Array Radars, IEEE Real-Time and Embedded Technology and Applications Symposium 2004, Toronto, Canada, May 2004
- C.-G. Lee, P.-S. Kang, C.-S. Shih, and L. Sha, Radar Dwell Scheduling Considering Physical Characteristics of Phased Array Antenna, IEEE Real-Time Systems Symposium 2003 (nominated for the best paper award), Cancun, Mexico, December 2003
- C.-G. Lee, Lui Sha, and A. Peddi, Enhanced Utilization Bounds for QoS Management, IEEE Transactions on Computers, Feb. 2004
- C.-G. Lee, Chi-Sheng Shih, and Lui Sha, Online QoS Optimization Using Service Classes in Surveillance Radar Systems, Journal of Real-Time Systems, 28, pp5-37, 2004
- K. Kim, J.L. Diaz, L.L. Bello, J.M. Lopez, C.-G. Lee, D.F. Garcia, S.L. Min, and O. Mirabella, An Exact Stochastic Analysis of Priority-Driven Periodic Real-Time Systems and Its Approximations, Submitted to IEEE Transactions on Software Engineering 2004
- P.-S. Kang and C.-G. Lee, Search and Track Coordination in Multi-Ship Multi-Radar Systems Using Schedulability Envelope, Submitted to Journal of Real-Time Systems, July 2004
- C.-G. Lee, P.-S. Kang, C.-S. Shih, and L. Sha, Schedulability Envelope for Real-Time Radar Dwell Scheduling, Submitted to IEEE Transactions on Computers, March 2004
- Outside Website
- QoS-driven protocol suites for wireless sensor networks
- Project Description
- People
- Eylem Ekici, Chang-Gun Lee, Emad Felemban, and Ryan Boder
- Publications
- Y. Gu, D. Bozdag, E. Ekici, F. Ozguner, and C.-G. Lee, Partitioning-Based Mobile Element Scheduling in Wireless Sensor Networks, Submitted to DCOSS 2005
- E. Felemban, C.-G. Lee, E. Ekici, R. Boder, and S. Vural, Probabilistic QoS Guarantee in Reliability and Timeliness Domains in Wireless Sensor Networks, to apear in INFOCOM 2005
- Outside Website
- Intersection Collision Warning System
- Project Description
- People
- Dr. Umit Ozguner, Dr. Eylem Ekici, Dr. Fusun Ozguner, Dr. Oscar Takeshita, Dr. Keith Redmill, Alberto Avila, Gokhan Korkmaz, Yiting Liu, and Heelim Teh
- Publications
- A. Dogan, G. Korkmaz, Y. Liu, F. Ozguner, U. Ozguner, K. Redmill, O. Takeshita, and K. Tokuda, "Evaluation of intersection collision warning system using inter-vehicle communication simulator," in Intelligent Transportation Systems, 2004. Proceedings, Washington, D.C., USA, Oct 2004, pp. 11031108.
- F. Ozguner, U. Ozguner, O. Takeshita, K. Redmill, Y. Liu, G. Korkmaz, A. Dogan, K. Tokuda, S. Nakabayashi, and T.Shimizu, "A simulation study of an intersection collision warning system," in International workshop on ITS Telecommunications Proceedings, Singapore, June 2004.
- Gokhan Korkmaz, Eylem Ekici, Fusun Ozguner, and Umit Ozguner, "Urban Multi-Hop Broadcast Protocols for Inter-Vehicle Communication Systems," in Proceedings of First ACM Workshop on Vehicular Ad Hoc Networks (VANET 2004), October 2004, pp. 76-85
- Outside Website
- Analysis of Hop-Distance Relationship in Spatially Random Sensor Networks
- Project Description
- People
- Dr. Eylem Ekici, and Serdar Vural
- Publications
- Emad Felemban, Chang-Gun Lee, Eylem Ekici, Ryan Boder, and Serdar Vural, "Probabilistic QoS Guarantee in Reliability and Timeliness Domains in Wireless Sensor Networks", to appear in the Proceedings of IEEE INFOCOM 2005
- Outside Website
- Wave Addressing for Dense Sensor Networks (WADS)
- Project Description
- People
- Dr. Eylem Ekici, and Serdar Vural
- Publications
- S. Vural, and E. Ekici, "Wave Addressing for Dense Sensor Networks," Proceedings of Second International Workshop on Sensor and Actor Network Protocols and Applications (SANPA 2004), pp. 56-66, August 2004.
- Outside Website
In order to satisfy and maintain Service Level Agreements (SLAs) which demand high network availability and good network health, Internet Service Providers (ISPs) have been instrumenting their networks with Network Measurement Infrastructures (NMIs). Traditionally simple tools such as Ping and Traceroute were integrated into NMIs to isolate problems relating to network connectivity and network topology. Today’s advances in popular Internet applications relying on complex, time-constrained, and bandwidth-intensive protocols, combined with the growing demand for sophisticated network measurements from researchers, ISPs and end-users, has led to the need for “Next-Generation Network Measurement Infrastructures” (NG-NMIs). We have developed a sophisticated network measurement toolkit called “ActiveMon” that is hosted on measurement beacons to perform application-specific measurements in NG-NMIs. In addition to ActiveMon, for orchestrating and regulating the network-wide application-specific measurements in NG-NMIs, we are developing a scalable and automated scheduling framework called “OnTimeMeasure”. The framework uses advanced principles of real-time scheduling- (a) to prevent network measurement resource conflicts and (b) to regulate the amount of measurement traffic injected into the network being measured.
The new millennium heralds the integration of computing, communication, and sensing for automated monitor and control of physical environments in many areas such as smart home/office, military, countering-terrorism, rescue, bio-sensing, and space research. For their success, it is critical to provide real-time guarantee along the end-to-end chain of computing, communication, and sensing. Although the research community has formed a sound real-time theory for computing and communication resources, less attention has been paid for newly emerging multi-functional smart sensing devices. This project aims at developing novel real-time scheduling algorithms and schedulability analysis for complex sensing devices including phased array radar, infrared thermal camera, and UAVs(unmanned aerial vehicles)/MAV (micro air vehicles). to fill the technology gap for eventually building the system-wide resource management framework that ensures end-to-end real-time interactions with the physical environments.
A sensor network is a valuable tool for gathering information and controlling/monitoring hostile environments. Most of sensor network applications require real-time packet delivery with certain reliability. They also have other QoS requirements like data fidelity and security. Thus, supporting those multi-domain QoS requirements is essential in designing a protocol suite for wireless sensor networks. However, it is a very challenging problem due to dynamic and unreliable natures of wireless sensor networks. In this project, we are aiming at developing a protocol suite for wireless sensor networks that can support diverse QoS requirements by optimal allocation of multi-dimensional resources like wireless channel, energy, and processing power. As a preliminary research, we developed MMSPEED (Multi-path Multi-layer SPEED) protocol that can provide probabilistic QoS guarantee in timeliness domain and reliability domain in a localized way. Since it relies on only local decisions of individual nodes without global network information, it preserves nice properties such as scalability, self-healing, and adaptability while continuously guaranteeing real-time and reliability requirements of packets. Extending this protocol suite, we will build a more rigorous framework that can handle multiple QoS domains such as timeliness, reliability, data fidelity, and security and multi-dimensional resources like wireless channel, energy, and processing power.
The evolution and general availability of inexpensive WLAN equipment and worldwide progress towards the acceptance of a DSRC standard fuelled the design and implementation efforts for Inter-vehicle Communication (IVC) systems in Intelligent Transportation Systems (ITS) applications. Intersection collision warning systems are one type of ITS applications which can prevent collisions or at least decrease the severity of them. By exchanging necessary information such as position, velocity, and acceleration, warning systems in vehicles can compute the possibility of a collision and warn drivers. This project is a multi-year study with OKI Electric Industry Co. dedicated to investigate protocol, radio unit performance and viability of an Intersection Collision System based on Inter-vehicle Communications through a combination of lab simulations and field tests. The simulator architecture of the Intersection Warning System developed at OSU is capable of evaluating different warning systems and communication protocols. In this simulator, the network layer, the physical layer, the driver behavior, and the vehicle traffic are modeled and simulated in detail. The simulation results show that IWS can significantly reduce both the vehicle collision percentage and the vehicle collision speed.
This study involves a stochastic study on the locations of sensors in spatially random sensor networks. Probabilistic bounds on the Euclidean distance that can be covered for a given hop distance from a designated source node is aimed to be found. The study involves one and two dimensional sensor networks. Results on one dimensional networks are obtained. Currently, the proposal for two dimensional networks is ready to be implemented. The results of this project can be applied to approximate localization of sensors without location information, one dimensional networks, e.g. vehicular networks, and studies involved with the relationship between hop distances and sensor field coverage. Recently, a paper is submitted using the work on one dimensional networks.
In this project, sensor locations with respect to hop distances from two designated sensor nodes are inspected using simulations. According to the hop distances from the source nodes, sensors are associated with ID numbers. IDs are disseminated through the network after sources broadcast packets. Groups of sensors are formed according to the ID pairs sensors have. A group's location is inspected by finding the expected position of the center of gravity using the Euclidean distances of sensors belonging to that group from the sources. The standard deviation of distances is determined to obtain the uncertainty in the center locations. The standard deviation of sensor positions with respect to center of gravity is found and designates the uncertainty in the separation of sensors from the group center. These values are obtained for every group and a coordinate system, called "Wave Mapping Coordinate" (WMC), based on the groups defined in such a way is established. This system is easy to implement and provides approximate localization of sensors. Currently the routing performance of this system is studied and compared with the case when location information of sensors is available and routing is performed over known positions. The WMC System is explained in the paper titled "Wave Addressing for Dense Sensor Networks" published in SANPA proceedings [1].