753 research outputs found

    Evaluation of human thermal response and building resilience to extreme heat events

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    Under the current and potential impact of climate change, there is a growing concern about extreme heat events and their challenges to human health and building resilience. The indoor heat-stress situation relates to the interaction of outdoor extreme heat events, building characteristics, and occupantsā€™ vulnerability. The high heat-related mortality rate of older people (aged 65+) and the trend of the population aging worldwide indicate the significant importance of evaluating and predicting heat-stress conditions for older people. Building thermal resilience determines the ability to tolerate extreme heat events and maintain or recover indoor comfort. Models of the relation between outdoor extreme weather data, indoor environment parameters, and human physiological responses are still needed to predict the consequences of global warming. Therefore, this research aims to evaluate building occupantsā€™ thermal response and quantify building thermal resilience against extreme heat events. The Bioheat models applicable to calculating young and older adultsā€™ physiological responses under hot exposure were developed. The validation study shows that the simulation results of the proposed models agree well with the published experimental data. The heat-stress index Standard Effective Temperature (SET) can be calculated based on the proposed Bioheat models and used in the selection of extreme hot years (EHY) and quantification of building thermal resilience. The EHY was selected by quantifying the degree of synchronization between outdoor heatwave events and building indoor overheating conditions based on the concept of POS (Percentage of Synchronization). It has been proved that in building overheating-centric studies, the EHYs should be selected according to the severity and intensity of heatwaves defined by SET. A new quantification framework for building thermal resilience against extreme heat events was developed. The framework includes the conceptual resilience trapezoid curve, Thermal Resilience Index (TRI), and resilience labelling system for zone level and building level resilience. The proposed framework has been implemented in a calibrated building model to quantify the building thermal resilience with different retrofit strategies. With this method, the effect of retrofit strategies and their combinations on the building and zonal thermal resilience can be quantified, labelled, and compared, thereby, a detailed design of resilience enhancement strategies to be achieved. The contributions of the thesis include validated new models and methods to quantify human thermal responses and building resilience to extreme heat events. These new methods and models contribute potentially significant impacts to the research under different climate zones and future climates covering from a single building to large scales to quantify community or city scale resilience to heat

    Distributed State Estimation for Linear Systems

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    This paper studies a distributed state estimation problem for both continuous- and discrete-time linear systems. A simply structured distributed estimator is first described for estimating the state of a continuous-time, jointly observable, input free, multi-channel linear system whose sensed outputs are distributed across a fixed multi-agent network. The estimator is then extended to non-stationary networks whose graphs switch according to a switching signal with a fixed dwell time or a variable but with fixed average dwell time, or switch arbitrarily under appropriate assumptions. The estimator is guaranteed to solve the problem, provided a network-widely shared gain is sufficiently large. As an alternative to sharing a common gain across the network, a fully distributed version of the estimator is thus studied in which each agent adaptively adjusts a local gain though the practicality of this approach is subject to a robustness issue common to adaptive control. A discrete-time version of the distributed state estimation problem is also studied, and a corresponding estimator is proposed for time-varying networks. For each scenario, it is explained how to construct the estimator so that its state estimation errors all converge to zero exponentially fast at a fixed but arbitrarily chosen rate, provided the network's graph is strongly connected for all time. This is accomplished by appealing to the ``split-spectrum'' approach and exploiting several well-known properties of invariant subspace. The proposed estimators are inherently resilient to abrupt changes in the number of agents and communication links in the inter-agent communication graph upon which the algorithms depend, provided the network is redundantly strongly connected and redundantly jointly observable.Comment: 17 pages, 8 figures. arXiv admin note: substantial text overlap with arXiv:1903.0548

    A Retrospective Paired Study: Efficacy and Safety of Nimotuzumab Combined with Radiochemotherapy in Locoregionally Advanced Nasopharyngeal Carcinoma

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    Objective: To evaluate the efficacy and safety of nimotuzumab in combination with radiochemotherapy as the primary treatment in patients with locoregionally advanced nasopharyngeal carcinoma (NPC). Methods: We retrospectively reviewed patients with locoregionally advanced nasopharyngeal carcinoma from September 2012 to December 2016. 188 newly diagnosed patients with stage IIIā€“IVB nasopharyngeal carcinoma were treated with at least 1-2 cycles of chemotherapy concurrently with planned IMRT. 88 patients received nimotuzumab 200 mg/week. Acute and late radiation-related toxicities were graded according to the Acute and Late Radiation Morbidity Scoring Criteria of Radiation Therapy Oncology Group. Results: After 3 months of treatment, the complete response rates of nasopharyngeal tumors in the study group and the control group were 78.4% and 65.5%, respectively (?2=4.070, P=0.044). The total complete response rates of cervical lymph nodes in the study group and the control group were 80.7% and 67.6% respectively (?2=4.022, P=0.045).The median cycle for nimotuzumab addition was 6.3 weeks. With a median follow-up of 36.3 months (range, 12ā€“72 months), the estimated 3-year progression failure-free survival and overall survival rates for the study group and the control group were 85.24% vs 81.97% and 96.67% vs 90.0%, respectively. The 3-year local recurrence-free survival rates for the study group and the control group were 96.67% vs 83.60%, respectively (P=0.047). Grade 3 radiation-induced mucositis accounted for 36.4% of treated patients. No skin rash and infusion reaction were observed, distinctly from what is reported in control patients. Conclusion: Nimotuzumab plus chemoradiotherapy in the treatment of locoregionally advanced nasopharyngeal carcinoma showed promising outcomes in terms of locoregional control, without increasing the incidence of radiation-related toxicities for patients

    Radiative absorption enhancement of dust mixed with anthropogenic pollution over East Asia

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    The particle mixing state plays a significant yet poorly quantified role in aerosol radiative forcing, especially for the mixing of dust (mineral absorbing) and anthropogenic pollution (black carbon absorbing) over East Asia. We have investigated the absorption enhancement of mixed-type aerosols over East Asia by using the Aerosol Robotic Network observations and radiative transfer model calculations. The mixed-type aerosols exhibit significantly enhanced absorbing ability than the corresponding unmixed dust and anthropogenic aerosols, as revealed in the spectral behavior of absorbing aerosol optical depth, single scattering albedo, and imaginary refractive index. The aerosol radiative efficiencies for the dust, mixed-type, and anthropogenic aerosols are āˆ’101.0, āˆ’112.9, and āˆ’98.3ā€‰Wmā»Ā²Ļ„ā»Ā¹ at the bottom of the atmosphere (BOA); āˆ’42.3, āˆ’22.5, and āˆ’39.8ā€‰Wmā»Ā²Ļ„ā»Ā¹ at the top of the atmosphere (TOA); and 58.7, 90.3, and 58.5ā€‰Wmā»Ā²Ļ„ā»Ā¹ in the atmosphere (ATM), respectively. The BOA cooling and ATM heating efficiencies of the mixed-type aerosols are significantly higher than those of the unmixed aerosol types over the East Asia region, resulting in atmospheric stabilization. In addition, the mixed-type aerosols correspond to a lower TOA cooling efficiency, indicating that the cooling effect by the corresponding individual aerosol components is partially counteracted. We conclude that the interaction between dust and anthropogenic pollution not only represents a viable aerosol formation pathway but also results in unfavorable dispersion conditions, both exacerbating the regional air pollution in East Asia. Our results highlight the necessity to accurately account for the mixing state of aerosols in atmospheric models over East Asia in order to better understand the formation mechanism for regional air pollution and to assess its impacts on human health, weather, and climate
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