228 research outputs found

    Experiments Validating the Effectiveness of Multi-point Wireless Energy Transmission with Carrier Shift Diversity

    Full text link
    This paper presents a method to seamlessly extend the coverage of energy supply field for wireless sensor networks in order to free sensors from wires and batteries, where the multi-point scheme is employed to overcome path-loss attenuation, while the carrier shift diversity is introduced to mitigate the effect of interference between multiple wave sources. As we focus on the energy transmission part, sensor or communication schemes are out of scope of this paper. To verify the effectiveness of the proposed wireless energy transmission, this paper conducts indoor experiments in which we compare the power distribution and the coverage performance of different energy transmission schemes including conventional single-point, simple multi-point and our proposed multi-point scheme. To easily observe the effect of the standing-wave caused by multipath and interference between multiple wave sources, 3D measurements are performed in an empty room. The results of our experiments together with those of a simulation that assumes a similar antenna setting in free space environment show that the coverage of single-point and multi-point wireless energy transmission without carrier shift diversity are limited by path-loss, standing-wave created by multipath and interference between multiple wave sources. On the other hand, the proposed scheme can overcome power attenuation due to the path-loss as well as the effect of standing-wave created by multipath and interference between multiple wave sources.Comment: This paper is submitted to IEICE IEICE Transactions on Communications.

    CHARACTERIZATION OF CARBONATED STEELMAKING SLAG AND ITS POTENTIAL APPLICATION IN CONSTRUCTION

    Get PDF
    In the current context of Vietnam, the solid waste of steel slag occupy ground for dumping and lead to severe environmental issue due to their high content of heavy metal and fine dust. For the purpose of large-scale recycling steel slag, up to now one of the most relevant solutions is to use as aggregate for asphaltic and/or cement concrete. In this paper, we aim to analyze the influence of the accelerated carbonation condition in the laboratory on the physio-chemical properties of carbonated steel slag. Materials composition were characterized by using different analysis techniques of XRD, SEM, TG and others measurement of the physio-properties (density, L.O.I..) were also realized with regards to the requirement of the national standard for concrete aggregate. In conclusion, we will discuss the effect of reaction condition and on the feasibility of implementing this specific treatment method on a larger scale.Keywords: steelmaking slag, solid waste, CO2 sequestration, accelerated carbonation, concrete aggregate

    ViHOS: Hate Speech Spans Detection for Vietnamese

    Full text link
    The rise in hateful and offensive language directed at other users is one of the adverse side effects of the increased use of social networking platforms. This could make it difficult for human moderators to review tagged comments filtered by classification systems. To help address this issue, we present the ViHOS (Vietnamese Hate and Offensive Spans) dataset, the first human-annotated corpus containing 26k spans on 11k comments. We also provide definitions of hateful and offensive spans in Vietnamese comments as well as detailed annotation guidelines. Besides, we conduct experiments with various state-of-the-art models. Specifically, XLM-RLarge_{Large} achieved the best F1-scores in Single span detection and All spans detection, while PhoBERTLarge_{Large} obtained the highest in Multiple spans detection. Finally, our error analysis demonstrates the difficulties in detecting specific types of spans in our data for future research. Disclaimer: This paper contains real comments that could be considered profane, offensive, or abusive.Comment: EACL 202

    Millimeter-wave Evolution for 5G Cellular Networks

    Full text link
    Triggered by the explosion of mobile traffic, 5G (5th Generation) cellular network requires evolution to increase the system rate 1000 times higher than the current systems in 10 years. Motivated by this common problem, there are several studies to integrate mm-wave access into current cellular networks as multi-band heterogeneous networks to exploit the ultra-wideband aspect of the mm-wave band. The authors of this paper have proposed comprehensive architecture of cellular networks with mm-wave access, where mm-wave small cell basestations and a conventional macro basestation are connected to Centralized-RAN (C-RAN) to effectively operate the system by enabling power efficient seamless handover as well as centralized resource control including dynamic cell structuring to match the limited coverage of mm-wave access with high traffic user locations via user-plane/control-plane splitting. In this paper, to prove the effectiveness of the proposed 5G cellular networks with mm-wave access, system level simulation is conducted by introducing an expected future traffic model, a measurement based mm-wave propagation model, and a centralized cell association algorithm by exploiting the C-RAN architecture. The numerical results show the effectiveness of the proposed network to realize 1000 times higher system rate than the current network in 10 years which is not achieved by the small cells using commonly considered 3.5 GHz band. Furthermore, the paper also gives latest status of mm-wave devices and regulations to show the feasibility of using mm-wave in the 5G systems.Comment: 17 pages, 12 figures, accepted to be published in IEICE Transactions on Communications. (Mar. 2015

    Impact of sand mining on sediment transport and morphological change of Hai Phong coastal area

    Get PDF
    The paper presents the results of simulating the impact of sand mining on sediment transport and morphological change in Hai Phong coastal area based on Delft3D model. Scenario groups are established: Present scenarios without sand mining and simulated scenarios of the present sand mining (assuming 30% sand compared to plan). The scenario groups are calculated in the dry and rainy seasons for main wind directions (NE, SE, SW) in the case of moderate wind and strong wind. The results show that sand mining reduces sediment flow alongshore (2–81%) and seawards (5–83%). Besides, the increase in depth causes morphological change in this area: Rising the deposition rate (5–10 mm/month) at the sand mining locations; decreasing accretion rate and increasing the erosion rate in the neighboring areas of sand mining location

    ANTI-SWAY TRACKING CONTROL OF OVERHEAD CRANE SYSTEM BASED ON PID AND FUZZY SLIDING MODE CONTROL

    Get PDF
    The paper presents a PID – Fuzzy Sliding Mode control (PID-FSMC) algorithm for overhead crane system to guarantee anti-sway trajectory tracking of the nominal plant. The proposed PID-FSMC law guarantees the closed-loop asymptotical stability as well as improveS the transient response of the load sway dynamics when the trolley is moving. The simulation results confirm the propriety of the proposed controller and show great promise of the controller application in practice
    • …
    corecore