Browsing by Author "Jeong, Jaehoon"

Now showing 1 - 9 of 9
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    APL: Autonomous Passive Localization for Wireless Sensors Deployed in Road Networks
    (2007-07-02) Jeong, Jaehoon; Guo, Shuo; He, Tian; DuHung-Chang, David
    In road networks, sensor nodes are deployed sparsely (hundreds of meters apart) to save costs. This makes the existing localization solutions based on the ranging ineffective. To address this issue, this paper introduces an autonomous passive localization scheme, called APL. Our work is inspired by the fact that vehicles move along routes with a known map. Using vehicle-detection timestamps, we can obtain distance estimates between any pair of sensors on roadways to construct a virtual graph composed of sensor identifications (i.e., vertices) and distance estimates (i.e., edges). The virtual graph is then matched with the topology of road map, in order to identify where sensors are located in roadways. We evaluate our design outdoor in local roadways and show that our distance estimate method works well despite of traffic noises. In addition, we show that our localization scheme is effective in a road network with eighteen intersections, where we found no location matching error, even with a maximum sensor time synchronization error of 0.3[sec] and the vehicle speed deviation of 10[km/h].
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    Energy-Aware Scheduling with Quality of Surveillance Guarantee in Wireless Sensor Networks
    (2006-06-21) Jeong, Jaehoon; Sharafkandi, Sarah; DuHung-Chang, David
    We propose and evaluate an energy-efficient scheduling algorithm for detection of mobile targets in wireless sensor networks. We consider a setting where the sensors are deployed for both road surveillance and mobile target tracking. A typical example would be where some sensors are deployed along the entrance roads of a city to detect the vehicles entering the city and other sensors can wake up and track the vehicles after detection. We show that there exists a tradeoff between overall energy consumed by the sensors and the average detection time of a target, both of which are very critical aspects in our problem. To this end, we define the quality of surveillance (QoSv) as the reciprocal value of the average detection time for vehicles. We propose an optimal scheduling algorithm that guarantees the detection of every target with specified QoSv and at the same time minimizes the overall energy consumed by the sensor nodes. By minimizing the energy consumed, we maximize the lifetime of the sensor network and by the quality of surveillance guarantee we ensure that no target goes undetected. We theoretically derive the upper bound on the lifetime of the sensor network for a given QoSv guarantee and prove that our method can always achieve this upper bound. Our simulation results validate the claims made on the algorithm optimality and QoSv guarantee.
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    MCTA: Target Tracking Algorithm based on Minimal Contour in Wireless SensorNetworks
    (2007-01-26) Jeong, Jaehoon; Hwang, TaeHyun; He, Tian; DuHung-Chang, David
    This paper proposes a minimal contour tracking algorithm (MCTA) that reduces energy consumption for tracking mobile targets in wireless sensor networks in terms of sensing and communication energy consumption. MCTA conserves energy by letting only a minimum number of sensor nodes participate in communication and perform sensing for target tracking. MCTA uses the minimal tracking area based on the vehicular kinematics. The modeling of target's kinematics allows for pruning out part of the tracking area that cannot be mechanically visited by the mobile target within scheduled time. So, MCTA sends the tracking area information to only the sensor nodes within minimal tracking area and wakes them up. Compared to the legacy scheme which uses circle-based tracking area, our proposed scheme uses less number of sensors for tracking in both communication and sensing without target missing. Through simulation, we show that MCTA outperforms the circle-based scheme with about 60% energy saving under certain ideal situations.
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    TBD: Trajectory-Based Data Forwarding for Light-Traffic Vehicular Networks
    (2008-11-24) Jeong, Jaehoon; Guo, Shuo; Gu, Yu; He, Tian; Hung-Chang Du, David
    This paper proposes a Trajectory-Based Data Forwarding (TBD) scheme, tailored for the data forwarding in light-traffic vehicular ad-hoc networks. We consider the scenarios in which Internet access points are sparsely deployed to receive the roadside reports of time-critical information such as driving accident or hazard. Since the Internet access points have limited communication coverage, a vehicular ad-hoc network is needed to forward data packets to the access points. State-of-the-art schemes have demonstrated the effectiveness of their data forwarding strategies by exploiting known vehicular traffic statistics (e.g., densities and speeds) in such a network. These results are encouraging, however, further improvements can be made by taking advantage of the growing popularity of GPS-based navigation systems. This paper presents the first attempt to investigate how to effectively utilize vehicles' trajectory information in a privacy-preserving manner. In our design, the trajectory information is combined with the traffic statistics to improve the performance of data forwarding in road networks. Through theoretical analysis and extensive simulation, it is shown that our design outperforms the existing scheme in terms of both the data delivery delay and packet delivery ratio, specially under light-traffic situations.
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    TMA: Trajectory-based Multi-Anycast for Multicast Data Delivery in Vehicular Networks
    (2011-07-26) Jeong, Jaehoon; He, Tian; DuHung-Chang, David
    This paper describes Trajectory-based Multi-Anycast (TMA) Forwarding, tailored and optimized for the multicast data delivery in vehicular networks. To our knowledge, this is the first attempt to investigate the efficient multicast data delivery in vehicle networks based on the trajectories of vehicles in the multicast group. Due to the privacy concern, we assume only a central server knows the trajectory of each vehicle and the estimated current location of the vehicle. Therefore, after receiving a request of multicast data delivery from a source vehicle, the central server has to figure out how the data has to be delivered to the vehicles in the multicast group. For a given target vehicle in the multicast group, multiple packet-andvehicle rendezvous points are computed as a set of relay nodes to temporarily hold the data along the vehicle's trajectory. This set of rendezvous points can be considered an Anycast set for the target vehicle. We have formulated the multicast data delivery as the data delivery to the anycast sets of the multicast group vehicles. Through theoretical analysis and extensive simulation, it is shown that our design provides an efficient multicast for moving vehicles under a variety of vehicular traffic conditions.
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    Travel Prediction-based Data Forwarding for Sparse Vehicular Networks
    (2011-07-28) Xu, Fulong; Guo, Shuo; Jeong, Jaehoon; Gu, Yu; Cao, Qing; Liu, Ming; He, Tian
    Vehicular Ad Hoc Networks (VANETs) represent promising technologies of cyber-physical systems for improving driving safety and communication mobility. Due to the highly dynamic driving patterns of vehicles, effective packet forwarding, especially for time sensitive data, has been a challenging research problem. Previous works forward data packets mostly utilizing statistical information about road network traffic, which becomes much less accurate when vehicles travel in sparse network as highly dynamic traffic introduces large variance for these statistics.With the popularity of on-board GPS navigation systems, individual vehicle trajectories become available and can be utilized for removing the uncertainty in road traffic statistics and improve the performance of the data forwarding in VANETs. In this paper, we propose Travel Prediction based Data-forwarding (TPD), in which vehicles share their trajectory information to achieve the low delay and high reliability of data delivery in multi-hop carry-and-forward environments. The driven idea is to construct a vehicle encounter graph based on pair-wise encounter probabilities, derived from shared trajectory information. With the encounter graph available, TPD optimizes delivery delay under a specific delivery ratio threshold, and the data forwarding rule is that a vehicle carrying packets always selects the next packet-carrier that can provide the best forwarding performance within the communication range. Through extensive simulations we demonstrate that TPD significantly outperforms existing schemes of TBD and VADD with more than 5% more packets delivery while reducing more than 40% delivery delay.
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    TSF: Trajectory-based Statistical Forwarding for Infrastructure-to-Vehicle Data Delivery in Vehicular Networks
    (2010-03-12) Jeong, Jaehoon; Guo, Shuo; Gu, Yu; He, Tian; Hung-Chang Du, David
    We consider the scenarios where Internet access points are sparsely deployed in road networks to provide individual vehicles with customized road condition information for the driving safety, such as holes and bumps along their trajectories. Due to the limited communication coverage, vehicular ad-hoc networks are used to support the multi-hop data forwarding. State-of-the-art schemes have demonstrated their effectiveness in the data forwarding from vehicles to stationary points (e.g., Internet access points). However, they are not designed for the reverse data forwarding from Internet access points to vehicles, a much more challenging problem because of the mobility of the packet destination. This paper proposes a data forwarding scheme called Trajectory-based Statistical Forwarding (TSF), tailored for the infrastructure-to-vehicle data delivery in vehicular networks. TSF forwards packets over multi-hop to a selected target point where the vehicle is expected to pass by. Such a target point is selected optimally to minimize the packet delivery delay while satisfying the required packet delivery probability. The optimality is achieved analytically by utilizing the packet's delivery delay distribution and the destination vehicle's travel delay distribution. To our knowledge, this paper presents the first attempt to investigate how to effectively utilize the destination vehicle's trajectory to compute such an optimal target point. Through theoretical analysis and extensive simulation, it is shown that our design provides an efficient data forwarding under a variety of vehicular traffic conditions.
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    VISA: Virtual Scanning Algorithm for Dynamic Protection of Road Networks
    (2008-08-22) Jeong, Jaehoon; Gu, Yu; He, Tian; DuHung-Chang, David
    This paper proposes a Virtual Scanning Algorithm (VISA), tailored and optimized for road network surveillance. Our design uniquely leverages upon the facts that (i) the movement of targets (e.g., vehicles) is confined within roadways and (ii) the road network maps are normally known. We guarantee the detection of moving targets before they reach designated protection points (such as temporary base camps), while maximizing the lifetime of the sensor network. The main idea of this work is virtual scan - waves of sensing activities scheduled for road network protection. We provide design-space analysis on the performance of virtual scan in terms of lifetime and average detection delay. Importantly, to our knowledge, this is the first work to study how to guarantee target detection while sensor network deteriorates, using a novel hole handling technique. Through theoretical analysis and extensive simulation, it is shown that a surveillance system, using our design, sustains orders-of-magnitude longer lifetime than full coverage algorithms, and as much as ten times longer than legacy duty cycling algorithms.
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    Wireless sensor networking for intelligent transportation systems.
    (2009-11) Jeong, Jaehoon
    This dissertation studies the Wireless Sensor Networking for Intelligent Transportation Systems, tailored and optimized for road networks. For military scenarios, since the road networks are used for main maneuver of military troops in cities or urban areas, they need to be protected for military operations. For civil engineering scenarios, the Intelligent Transportation Systems have been developed and been evolving to support the driving safety and transportation efficiency through the information computing and communications among transportation infrastructures and vehicles. Roadways are mainly used for the transportation of people and goods and also are nowadays equipped with intelligent devices, such as electronic tollgates and variable message signs for driving. In addition to this, vehicles are equipped with GPS-based navigation systems and emergency notification systems for the driving efficiency and safety. With this trend, Wireless Sensor Networks have been considered new parts for the Intelligent Transportation Systems and are being deployed into road networks in order to enhance further the driving safety and security. This dissertation studies the key technologies in the wireless sensor networking for the security and communications in the road networks as follows: (i) Localization for sensor location, (ii) Road Surveillance for vehicle monitoring, (iii) Data Forwarding for road sensing data delivery and (iv) Reverse Data Forwarding for road condition information sharing. In order to design the technologies to be tailored for road networks, this dissertation investigates the characteristics of road networks and takes advantage of the characteristics for the wireless networking. The first characteristic is the predictable vehicle mobility within the roadways. The second is the abstract representation of the layouts of the road networks into road maps. The third is the vehicular traffic statistics representing the vehicle density on the roadways and intersections. The fourth is the vehicle trajectory representing the future vehicle mobility along the roadways, guided by the GPS navigation systems. These four characteristics open a door of new research on wireless sensor networks. Therefore, using these road network characteristics, this dissertation designs and evaluates the wireless sensor networking technologies for road networks.