39 research outputs found

    Hierarchical Quantification of Utilization Rate and Related Indicators of Mixed-Use High-Rise Buildings

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    Mixed-use high-rise buildings are vertical superpositions of various business types in the category of mixed-use development. It has become a highly intensive organizational form in the urban high-density environment. Under China’s “height limit” policy, the simple superposition of business types does not meet the government requirements for planning, construction, and management, and does not fully utilize the advantages of the mixed development mode. The single utilization rate index used in the past could not accurately describe such buildings’ usage value and spatial variation characteristics. In this study, a quantitative analysis of data from eight construction projects was carried out, and a utilization rate index system was established at three levels, namely, the typical floor utilization rate k1, business utilization rate k2, and building utilization rate k3. In terms of k1, the emphasis was placed on the design elements of the mixed-use development and the variation of relative indicators. In k2 and k3, it was found that the business type, floor area, and utilization rate were negatively correlated. In conclusion, by establishing a hierarchical utilization rate calculation method, the efficiency values and design characteristics of mixed-use high-rise (MUHR) buildings were explored, which provide references for the future design of such building

    Optimal Hybrid Beamforming Design for Millimeter-Wave Massive Multi-User MIMO Relay Systems

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    As a promising technology in the next generation mobile network, millimeter-wave (mmWave) communication can mitigate the spectrum crunch of improving the network capacity by exploiting the large underutilized spectrum bands of the mmWave frequencies. The hybrid (analog/digital) beamforming of multi-data streams are widely used to further the spectrum efficiency of mmWave relay system when faced with the complex environment or long distance communication. This paper investigates the hybrid beamforming scheme for the decode-and-forward (DF) mmWave massive multiple-input multiple-output (MIMO) relay system with mixed structure and full-connected structure. We optimize hybrid beamforming of relay system by maximizing the sum rate of the overall system as an objective function. To reduce the computational complexity, we reformulate the original problem as two single-hop mmWave MIMO sum-rate maximization subproblems. Then, the piecewise successive approximation method is proposed based on the criterion which jointly designs the analog and digital beamforming stages by trying to avoid the loss of information at each stage. The hybrid beamforming of the two subproblems can be solved by the proposed scheme united with the idea of successive interference cancelation (SIC), the baseband block diagonalization (BD) scheme, and waterfilling power allocation method. Finally, simulation results confirm that the proposed optimal method can achieve good performance in hybrid beamforming design of relay system with both mixed and full-connected structures

    Semi-blind joint channel estimation and symbol detection for RIS-empowered multiuser mmWave Systems

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    In this letter, we propose a semi-blind joint channel estimation and symbol detection scheme for reconfigurable intelligent surface (RIS)-empowered multiuser millimeter wave (mmWave) systems. Combined with the coding scheme at user equipments (UEs) and RIS reflection coefficient design, we prove that the received signals at the base station (BS) follow a PARATUCK2 tensor model, and then a two-stage fitting algorithm is derived by exploiting the low-rank structure of mmWave channel. Without a dedicated training stage, the proposed scheme can jointly detect information symbols of all UEs and estimate the channels of the UEs-RIS and RIS-BS links. In comparison to the existing methods, the proposed system can increase spectrum efficiency and obtain better channel estimation and symbol detection performance. Numerical results are presented to verify the effectiveness of the proposed scheme

    Near-Optimal Design for Hybrid Beamforming in mmWave Massive Multi-User MIMO Systems

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    Millimeter wave (mmWave) massive multiple-input multiple-output (MIMO) systems can obtain sufficient beamforming gains to combat severe path loss in signal propagation. The hybrid (analog/digital) beamforming with multiple data streams can be utilized to further improve mmWave spectral efficiency. In this paper, we focus on the hybrid beamforming design of a downlink mmWave massive multi-user MIMO (MU-MIMO) system based on full-connected structure, and aim to maximize the sum rate of the overall system as an objective function. In the analog beamforming stage, a piecewise successive iterative approximation (PSIA) algorithm is proposed to design the analog beamformer and combiner. This algorithm not only has a linear property, but also can obtain closed-form solutions. In the digital beamforming stage, the piecewise successive approximation method is utilized to design the digital beamforming based on the criterion to avoid the loss of information, which can help reduce the computational complexity and is also implemented simply. The results show that the proposed scheme achieves good sum-rate performance in the mmWave massive MU-MIMO system, and outperforms the state-of-the art MIMO hybrid beamforming design schemes, even when the number of base station antennas is not very large

    Hybrid beamforming with sub-connected structure for MmWave massive multi-user MIMO relay systems

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    In this paper, we investigate the hybrid beamforming design with sub-connected structure for millimeter-wave (mmWave) massive multi-user multiple-input multiple-output (MU-MIMO) amplify-and-forward (AF) relay systems. Considering the constant-modulus and block-diagonal constraints, an iterative algorithm is proposed to sequentially design the analog beamforming of the base station, relay, and users. Next, the relay baseband combiner is designed by transforming the highly complicated non-convex mutual information maximization problem into an easily tractable weighted minimum mean squared error one. To mitigate the inter-user interference, a successive serial interference cancellation based and a piecewise successive approximation based methods are developed for the uniform sparse distribution and dense distribution scenarios, respectively. Simulation results demonstrate that the two proposed hybrid beamforming schemes can achieve good performance in terms of sum-rate and energy efficiency, and outperform benchmarks significantly. In addition, the two proposed schemes are shown to be robust to imperfect channel state information (CSI), even though they are studied based on perfect CSI

    Analysis of Interrelated Network Improvement Alternatives

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    69A43551747123This project developed methods for optimizing the long-term development of road networks by developing algorithms for selecting, sequencing and scheduling interrelated improvements, which change flows through the networks. It also compared how network performance can be evaluated as a network\u2019s configuration evolves, using either a fast traffic assignment algorithm or the slower but more realistically precise microscopic simulation model INTEGRATION. The results indicate when and to what extent the traffic assignment algorithm can approximate the simulation results. They demonstrate the potential value of hybrid methods in combining initial search with traffic assignment and refined search with microscopic simulation

    Maximizing the potential of aggressive mouse tumor models in preclinical drug testing.

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    Atypical teratoid rhabdoid tumor (ATRT) is an aggressive embryonal brain tumor among infants and young children. Two challenges exist for preclinical testing in ATRT. First, genetically quiet, ATRT is a difficult tumor to target molecularly. Tumor cells need to divide to propagate tumor growth-intercepting the common crossroads in cell cycle progression is a feasible strategy. KIF11 is needed for bipolar spindle formation in metaphase. We identified KIF11 as a universal target of all ATRT-molecular-subtypes. Ispinesib, a KIF11-inhibitor, effectively inhibited tumor proliferation in all seven cell lines. A second challenge-a major challenge in preclinical drug testing in-vivo among aggressive tumor models, is the narrow therapeutic window to administer drugs within the limited murine lifespan. Our most aggressive ATRT tumor model was lethal in all mice within ~ 1 month of tumor implantation. Such short-surviving mouse models are difficult to employ for preclinical drug testing due to the narrow time window to administer drugs. To overcome this time restriction, we developed a clinical staging system which allowed physically-fit mice to continue treatment, in contrast to the conventional method of fixed drug-dose-duration regimen in preclinical testing which will not be feasible in such short-surviving mouse models. We validated this approach in a second embryonal brain tumor, medulloblastoma. This is a clinically relevant, cost-efficient approach in preclinical testing for cancer and non-cancer disease phenotypes. Widely used preclinical mouse models are not the most accurate and lack the aggressive tumor spectrum found within a single tumor type. Mice bearing the most aggressive tumor spectrum progress rapidly in the limited murine life-span, resulting in a narrow therapeutic window to administer drugs, and are thus difficult to employ in preclinical testing. Our approach overcomes this challenge. We discovered ispinesib is efficacious against two embryonal brain tumor types

    Fare Free Public Transportation: A Full-Scale Real-World Experiment in Alexandria (VA)

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    69A43551747123The Fare Free Public Transportation (FFPT) concept is a common part of the agenda among transit agencies and state and federal policy makers. The subject is particularly important in the post-pandemic period, as transit use is slowly recovering but has not yet reached pre-pandemic ridership and market share. FFPT has been implemented in Europe and to a certain degree in the USA; however, there are very few studies that have effectively collected data and evaluated the consequences with respect to its implementation. This study monitored a full-scale, real-world FFPT plan implemented in Alexandria, VA in the Fall of 2021, separating respondents into treatment and control groups. Descriptive statistics indicated minimal disparity between the treatment and control groups across most socio-demographic variables. Notably, residents of Alexandria exhibit a higher propensity to use buses compared to the control group, both prior to and post-policy implementation. Regarding awareness of the policy, a majority of respondents were uninformed, while the policy's impact is more pronounced among those who were aware. Around 32% of respondents increased their bus usage following FFPT implementation, with approximately 80% of this subset utilizing buses more frequently than before. This policy evaluation is relevant not only to Alexandria, but to many stakeholders across the country that are considering similar policies in other cities
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