Lawrence Wai-Choong Wong

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The emergence of personal mobile device with low cost sensors, such as accelerometer and digital compass, has made dead-reckoning (DR) an attractive choice for indoor pedestrian tracking. In this paper, we propose a robust DR pedestrian tracking system on top of such commercially accessible sensor sets capable of DR. The proposed method exploits the fact(More)
Energy awareness is a crucial component in the design of wireless sensor networks at all layers. This paper looks into efficient energy utilization of a target-tracking sensor network by predicting a target’s trajectory through experience. While this is not new, the chief novelty comes in conserving energy through both dynamic spatial and temporal(More)
This paper surveys recently proposed works on Intrusion Detection Systems (IDS) in WSNs, and presents a comprehensive classification of various IDS approaches according to their employed detection techniques. The three main categories explored in this paper are anomaly detection, misuse detection, and specification-based detection protocols. We give a(More)
In this paper, we consider the medium access control (MAC) protocol design for random access cognitive radio networks (CRNs). A two-level opportunistic spectrum access strategy is proposed to optimize system performance of the secondary network, and to adequately protect the operation of the primary network. At the first level, secondary users (SUs)(More)
In this paper, we propose an optimized content-aware authentication scheme for JPEG-2000 streams over lossy networks, where a received packet is consumed only when it is both decodable and authentic. In a JPEG-2000 codestream some packets are more important than others in terms of coding dependency and visual quality. This inspires us to allocate more(More)
In this paper, we consider the cooperative spectrum sensing problem for a cognitive radio (CR) mesh network, where secondary users (SUs) are allowed to share the spectrum band which is originally allocated to a primary users' (PUs) network. We propose two new cooperative spectrum sensing strategies, called amplify-and-relay (AR) and detect-and-relay (DR),(More)
Existing approaches to indoor tracking have various limitations. Location-fingerprinting approaches are labor intensive and vulnerable to environmental changes. Trilateration approaches require at least three line-of-sight beacons for coverage at any point in the service area, which results in heavy infrastructure cost. Dead reckoning (DR) approaches rely(More)
In this paper, we propose a fingerprint-based localization scheme that exploits the location dependency of the channel impulse response (CIR). We approximate the CIR by applying Inverse Fourier Transform to the receiver’s channel estimation. The amplitudes of the approximated CIR (ACIR) vector are further transformed into the logarithmic scale to ensure(More)