191 research outputs found

    TOA-based indoor localization and tracking with inaccurate floor plan map via MRMSC-PHD filter

    Get PDF
    This paper proposes a novel indoor localization scheme to jointly track a mobile device (MD) and update an inaccurate floor plan map using the time-of-arrival measured at multiple reference devices (RDs). By modeling the floor plan map as a collection of map features, the map and MD position can be jointly estimated via a multi-RD single-cluster probability hypothesis density (MSC-PHD) filter. Conventional MSC-PHD filters assume that each map feature generates at most one measurement for each RD. If single reflections of the detected signal are considered as measurements generated by map features, then higher-order reflections, which also carry information on the MD and map features, must be treated as clutter. The proposed scheme incorporates multiple reflections by treating them as virtual single reflections reflected from inaccurate map features and traces them to the corresponding virtual RDs (VRDs), referred to as a multi-reflection-incorporating MSC-PHD (MRMSC-PHD) filter. The complexity of using multiple reflection paths arises from the inaccuracy of the VRD location due to inaccuracy in the map features. Numerical results show that these multiple reflection paths can be modeled statistically as a Gaussian distribution. A computationally tractable implementation combining a new greedy partitioning scheme and a particle-Gaussian mixture filter is presented. A novel mapping error metric is then proposed to evaluate the estimated map's accuracy for plane surfaces. Simulation and experimental results show that our proposed MRMSC-PHD filter outperforms the existing MSC-PHD filters by up to 95% in terms of average localization and by up to 90% in terms of mapping accuracy

    An Indoor Localization and Tracking System Using Successive Weighted RSS Projection

    Get PDF
    This letter proposes a novel successive weighted received signal strength (RSS) indoor localization and tracking system that projects previous time instance estimated mobile device (MD) position to provide projected RSS values. Such RSS projection increases the number of available RSS from Nm to Nm + N AP , where N AP is the total number of access points and Nm is the number of RSS values measured by MD, ranging from 0 to N AP . Our proposed system thus resolves the issues associated with insufficient or no RSS values received by MD. Inertial navigation system (INS) is merged with RSS localization system to provide a weighted fusion of projected and measured RSS values. The weighting factors are derived based on the INS and RSS localization accuracy where the former is initially accurate but deteriorates with time and the latter is time-independent but environment-dependent. The proposed system was tested in indoor environments and outperformed other existing localization systems such as RSS and INS fusion using extended Kalman filter and non-line-of-sight (NLOS) selection scheme, especially in heavy multipath environment, by 42% and 75%, respectively

    Localization in GPS denied environment

    Get PDF
    No abstract available

    Liver Transplantation in an Adult with Citrullinaemia Type 2

    Get PDF
    Citrullinaemia is a urea cycle defect that results from a deficiency of the enzyme arginosuccinate synthetase. Type 1 disease is diagnosed in childhood, whereas Type 2 disease is adult onset. We report the outcome of a patient with citrullinemia Type 2 who received a liver transplant at our center and the implications of this diagnosis in liver transplantation

    First record of jellyfish Anomalorhiza shawi Light, 1921 (Cnidaria: Scyphozoa) and its associated organisms in Sabah, Malaysia

    Get PDF
    The present study describes a first record of the jellyfish Anomalorhiza shawi Light, 1921 from Malaysia. It belongs to the family Lychnorhizidae Haeckel, 1880, order Rhizostomeae Cuvier, 1799 (Cnidaria: Scyphozoa). The specimen was taken from Sepanggar Bay, Kota Kinabalu, off the Universiti Malaysia Sabah (UMS) Jetty by manual collection with a bucket. The size of the bell was 430 mm in diameter with oral arms measuring 290 mm in length including the brown terminal clubs, which differentiates A. shawi from other congeners of the family. Anomalorhiza shawi belongs to the monotypic genus Anomalorhiza, and was first reported from the Philippines, with later reports from Hawaii and Thailand. In addition, A. shawi was found associated with other organisms such as the silver shad, Alepes vari (Cuvier, 1833) (Carangidae), and the crab Charybdis feriata (Linnaeus, 1758) (Portunidae). The association between jellyfish and other organisms have been discussed here. A checklist is provided for the current species of scyphozoan jellyfish reported from Malaysia

    Masquerading Hypervascular Exophytic Liver Nodule

    Get PDF
    Patients with liver cirrhosis are at increased risk of developing hepatocellular carcinoma (HCC) and are placed on routine surveillance for HCC. Diagnosis algorithms are in place to guide clinicians in the evaluation of liver lesions detected during surveillance. Radiological assessments are critical with diagnostic criteria based on identification of typical hallmarks of HCCs on multiphasic computed tomography (CT) and dynamic contrast-enhanced magnetic resonance imaging (MRI). We report a patient with a hypervascular exophytic lesion indeterminate for HCC on CT imaging. While the detection of an exophytic arterially-enhancing lesion in an at-risk patient on CT imaging may prompt clinicians to treat the lesion as HCC without further evaluation, the patient underwent contrast-enhanced MRI with the lesion being eventually diagnosed as an exophytic haemangioma. Thus, no further action was necessary and the patient was continued on routine HCC surveillance

    Intelligent Massive MIMO Systems for Beyond 5G Networks: An Overview and Future Trends

    Get PDF
    Machine learning (ML) which is a subset of artificial intelligence is expected to unlock the potential of challenging large-scale problems in conventional massive multiple-input-multiple-output (CM-MIMO) systems. This introduces the concept of intelligent massive MIMO (I-mMIMO) systems. Due to the surge of application of different ML techniques in the enhancement of mMIMO systems for existing and emerging use cases beyond fifth-generation (B5G) networks, this article aims to provide an overview of the different aspects of the I-mMIMO systems. First, the characteristics and challenges of the CM-MIMO have been identified. Secondly, the most recent efforts aimed at applying ML to a different aspect of CM-MIMO systems are presented. Thirdly, the deployment of I-mMIMO and efforts towards standardization are discussed. Lastly, the future trends of I-mMIMO-enabled application systems are presented. The aim of this paper is to assist the readers to understand different ML approaches in CM-MIMO systems, explore some of the advantages and disadvantages, identify some of the open issues, and motivate the readers toward future trends

    5G-Wi-SUN for Building Management System

    Get PDF
    With higher data rates and lower latency, 5G constitutes a mobile alternative to both wired networks and less capable wireless solutions. However, the performance of 5G requires expensive hardware and high energy consumption, making it less suitable for energy-constrained edge devices. Combining the capabilities of 5G for Wide Area Network (WAN) access, with the benefits of other wireless networks purpose-built for low-power embedded systems, a Building Management System (BMS) based on 5G can be deployed anywhere in a building with 5G coverage extended with a suitable LPWAN connectivity for IoT devices of the BMS. In this paper, the LPWAN of choice is the Wireless Smart Utility Network (Wi-SUN), a low-power sub-GHz connectivity based on IEEE 802.15.4g, offering mesh and multi-hop features for improved reliability and range, alongside competitive data rates. The performance of a 5G-Wi-SUN hybrid network was evaluated with a fibre-broadband hybrid network, a 5G-only network and a Wi-SUN-only network to determine the feasibility of 5G-Wi-SUN network. Test results show a significant performance of our 5G-WiSUN network, with a round-trip times below half a second in most cases, and a trimean of 115ms, only 27ms more than the fibre broadband-WiSUN network in our experiment. Consequently, the results have demonstrated the ability of a 5G-Wi-SUN network to provide a versatile alternative to fibre broadband-WiSUN, while maintaining a comparable performance
    corecore