Po-Yu Chen

Bio: Po-Yu Chen is an academic researcher from National Tsing Hua University. The author has contributed to research in topics: Wireless sensor network & Key distribution in wireless sensor networks. The author has an hindex of 13, co-authored 24 publications receiving 583 citations. Previous affiliations of Po-Yu Chen include Academia Sinica & National Chiao Tung University.

Design and Implementation of a Real Time Video Surveillance System with Wireless Sensor Networks

Abstract: One important goal of surveillance systems is to collect information about the behavior and position of interested targets in the sensing environment. These systems can be applied to many applications, such as fire emergency, surveillance system, and smart home. Recently, surveillance systems combining wireless sensor networks with video cameras have become more and more popular. In traditional video surveillance systems, the system performance and cost is proportional to the number of deployed video camera. In this paper, we propose a real time video surveillance system consisting of many low cost sensors and a few wireless video cameras. The system allows a group of cooperating sensor devices to detect and track mobile objects and to report their positions to the sink node in the wireless sensor network. Then, the sink node uses the IP cameras deployed in the sensing area to record these events and display the present situations. We also propose a camera control scheme to initialize the coverage distribution of cameras and support the inter-task handoff operations between cameras. We have implemented the proposed system with 16 sensor nodes and two IP cameras, and evaluated the system performance. The result shows that our surveillance system is adaptable to variant environments and provides real time information of the monitored environment.

An Efficient Downlink Radio Resource Allocation with Carrier Aggregation in LTE-Advanced Networks

Abstract: In long term evolution-advanced (LTE-A) networks, the carrier aggregation technique is incorporated for user equipments (UEs) to simultaneously aggregate multiple component carriers (CCs) for achieving higher transmission rate. Many research works for LTE-A systems with carrier aggregation configuration have concentrated on the radio resource management problem for downlink transmission, including mainly CC assignment and packet scheduling. Most previous studies have not considered that the assigned CCs in each UE can be changed. Furthermore, they also have not considered the modulation and coding scheme constraint, as specified in LTE-A standards. Therefore, their proposed schemes may limit the radio resource usage and are not compatible with LTE-A systems. In this paper, we assume that the scheduler can reassign CCs to each UE at each transmission time interval and formulate the downlink radio resource scheduling problem under the modulation and coding scheme constraint, which is proved to be NP-hard. Then, a novel greedy-based scheme is proposed to maximize the system throughput while maintaining proportional fairness of radio resource allocation among all UEs. We show that this scheme can guarantee at least half of the performance of the optimal solution. Simulation results show that our proposed scheme outperforms the schemes in previous studies.

A Fuel-Saving and Pollution-Reducing Dynamic Taxi-Sharing Protocol in VANETs

Abstract: Traffic congestion is a serious problem in urban areas of many countries due to the increasing amount of vehicles on surface streets and accompanies fuel-wasting and air-pollution. This problem can be alleviated by adopting a ride-sharing service. The main idea of ride-sharing service is to collect travelers whose travel destinations are nearby into one vehicle. In doing so, we can reduce the amount of vehicles on surface streets and meantime save fuel. In this paper, we focus on the taxi-sharing service and propose a dynamic taxi-sharing system based on Intelligent Transportation Systems (ITS) technology. In the proposed system, we can immediately serve each irregular ride-sharing request and find a fuel-saving taxi for it. The simulation results show that our solution can exactly select a fuel-saving taxi for each ride-sharing request and outperform in responding time, the number of compared taxis, and fuel-saving while comparing with existing solutions.

Dynamic Taxi-Sharing System and Sharing Method Thereof

Abstract: A dynamic taxi-sharing system and a sharing method thereof. A ride-sharing service provider carries at least one passenger from the first current location to the first travel destination through a route in an area and sends registration information to a service server. A plurality of ride-sharing requests is sent to the service server, and each of the ride-sharing requests comprises the second current location and the second travel destination. The service server divides the area into n by n blocks. A ride-matching module of the service server chooses a destination area in which the first travel destination is a center point and divides the destination area into k by k blocks. According to the registration information and the ride-sharing requests, the ride-matching module matches at least one ride-sharing traveler to the ride-sharing service provider to achieve a goal of fuel-saving and pollution-reducing.

A Novel Emergency Vehicle Dispatching System

Abstract: When accidents or disasters happen, emergency response time is always crucial. Most procedures in the existing emergency vehicle dispatching systems rely heavily on manual assignments. In this paper, we propose a novel emergency vehicle dispatching system to reduce emergency response time, which includes automatic emergency resource assignment and driving path planning to reduce unnecessary time delay caused by human misjudgment or the delay caused by traffic jam. As the traffic condition varies from time to time, the traffic information employed in the proposed method needs to trace back to several weeks prior to the dispatching time. Furthermore, we also propose a lane reservation scheme for emergency vehicles to minimize the crash risks. Before an emergency vehicle arrives at each road segment, Road Side Units start to disseminate the warning message at suitable time, so that other drivers could have enough time to take proper actions such as speed acceleration or switching lanes. Simulation results show that the proposed approach can largely reduce the traveling time of emergency vehicles comparing to the shortest path approach with sirens and lights to alert other drivers. With the traveling time as well as emergency resource assignment time being reduced, the emergency rescue teams would gain edges in rescuing lives and property.

Predicting Taxi–Passenger Demand Using Streaming Data

Abstract: Informed driving is increasingly becoming a key feature for increasing the sustainability of taxi companies. The sensors that are installed in each vehicle are providing new opportunities for automatically discovering knowledge, which, in return, delivers information for real-time decision making. Intelligent transportation systems for taxi dispatching and for finding time-saving routes are already exploring these sensing data. This paper introduces a novel methodology for predicting the spatial distribution of taxi-passengers for a short-term time horizon using streaming data. First, the information was aggregated into a histogram time series. Then, three time-series forecasting techniques were combined to originate a prediction. Experimental tests were conducted using the online data that are transmitted by 441 vehicles of a fleet running in the city of Porto, Portugal. The results demonstrated that the proposed framework can provide effective insight into the spatiotemporal distribution of taxi-passenger demand for a 30-min horizon.

Smart Cities: A Survey on Data Management, Security, and Enabling Technologies

Abstract: Integrating the various embedded devices and systems in our environment enables an Internet of Things (IoT) for a smart city. The IoT will generate tremendous amount of data that can be leveraged for safety, efficiency, and infotainment applications and services for city residents. The management of this voluminous data through its lifecycle is fundamental to the realization of smart cities. Therefore, in contrast to existing surveys on smart cities we provide a data-centric perspective, describing the fundamental data management techniques employed to ensure consistency, interoperability, granularity, and reusability of the data generated by the underlying IoT for smart cities. Essentially, the data lifecycle in a smart city is dependent on tightly coupled data management with cross-cutting layers of data security and privacy, and supporting infrastructure. Therefore, we further identify techniques employed for data security and privacy, and discuss the networking and computing technologies that enable smart cities. We highlight the achievements in realizing various aspects of smart cities, present the lessons learned, and identify limitations and research challenges.

Data communication in VANETs

Abstract: VANETs have emerged as an exciting research and application area. Increasingly vehicles are being equipped with embedded sensors, processing and wireless communication capabilities. This has opened a myriad of possibilities for powerful and potential life-changing applications on safety, efficiency, comfort, public collaboration and participation, while they are on the road. Although, considered as a special case of a Mobile Ad Hoc Network, the high but constrained mobility of vehicles bring new challenges to data communication and application design in VANETs. This is due to their highly dynamic and intermittent connected topology and different application's QoS requirements. In this work, we survey VANETs focusing on their communication and application challenges. In particular, we discuss the protocol stack of this type of network, and provide a qualitative comparison between most common protocols in the literature. We then present a detailed discussion of different categories of VANET applications. Finally, we discuss open research problems to encourage the design of new VANET solutions.