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ABSTRACTPrevious studies generally used land use and travel flow to investigate the efficiency of the railway system in Transit-Oriented Development (TOD) cities. Furthermore, to study the association of land use and jobs–housing distribution of commuters, we can find out the potential development of rail commuting. In this research, four railway lines in Wuhan, China, were selected to explore the land use in promoting practical commuting population according to the smart-card data obtained. For land use issues, except the road density and building density, a Normalized Location-Weighted Landscape Index (NLWLI) based on the source – sink theory in landscape ecology was established to assess the jobs–housing land use around rail transit stations. Meanwhile, employment and housing details of commuters around rail transit stations were identified using smart-card data. We found that the generation of commuting flow was affected by building density and the land use of employment in the immediate vicinity of rail transit stations. The distribution of building density and commuters in a mature rail line was roughly a normal distribution. However, due to the inconsistency of land use and jobs – housing distribution around stations, the requirement of the balance of land use and jobs – housing distribution should be reduced at the scale of rail stations in the TOD planning systems. This study is the application of massive smart-card data in the field of urban research. It identifies land use issues that affect rail transit commuting flow, and can help urban planners improve the efficiency of rail transit through planning and design.

Estimation of impervious surface area is important to the study of urban environments and social development, but surface characteristics, as well as the temporal, spectral, and spatial resolutions of remote sensing images, influence the estimation accuracy. To investigate the effects of regional environmental characteristics on the estimation of impervious surface area, we divided China into seven sub-regions based on climate, soil type, feature complexity, and vegetation phenology: arid and semi-arid areas, Huang-Huai-Hai winter wheat production areas, typical temperate regions, the Pearl River Delta, the middle and lower reaches of the Yangtze River, typical tropical and subtropical regions, and the Qinghai Tibet Plateau. Impervious surface area was estimated from Landsat 8 images of five typical cities, including Yinchuan, Shijiazhuang, Shenyang, Ningbo, and Kunming. Using the linear spectral unmixing method, impervious and permeable surface areas were determined at the pixel-scale based on end-member proportions. We calculated the producer’s accuracy, user’s accuracy, and overall accuracy to assess the estimation accuracy, and compared the accuracies among images acquired from different seasons and locations. In tropical and subtropical regions, vegetation canopies can confound the identification of impervious surfaces and, thus, images acquired in winter, early spring, and autumn are most suitable; estimations in the Pearl River Delta, the middle and lower reaches of the Yangtze River are influenced by soil, vegetation phenology, vegetation canopy, and water, and images acquired in spring, summer, and autumn provide the best results; in typical temperate areas, images acquired from spring to autumn are most effective for estimations; in winter wheat-growing areas, images acquired throughout the year are suitable; and in arid and semi-arid areas, summer and early autumn, during which vegetation is abundant, are the optimal seasons for estimations. Knowledge of optimal time frames, multi-source data, and intelligent algorithms should be integrated to reduce spectral confusion and improve the estimation of impervious surface area from Landsat 8 OLI imagery.

Physically unclonable functions (PUFs) are hardware security primitives that utilize non-reproducible manufacturing variations to provide device-specific challenge-response pairs (CRPs). Such primitives are desirable for applications such as communication and intellectual property protection. PUFs have been gaining considerable interest from both the academic and industrial communities because of their simplicity and stability. However, many recent studies have exposed PUFs to machine-learning (ML) modeling attacks. To improve the resilience of a system to general ML attacks instead of a specific ML technique, a common solution is to improve the complexity of the system. Structures, such as XOR-PUFs, can significantly increase the nonlinearity of PUFs to provide resilience against ML attacks. However, an increase in complexity often results in an increase in area and/or a decrease in reliability. This study proposes a lightweight ring oscillator (RO)-based PUFs using an additional modulus process to improve ML resiliency. The idea was to increase the complexity of the RO-PUF without significant hardware overhead by applying a modulus process to the outcomes from the RO frequency counter. We also present a thorough investigation of the design space to balance ML resiliency and other performance metrics such as reliability, uniqueness, and uniformity.

Physical unclonable functions (PUFs) are a strong and secure root source for identification and authentication applications. PUFs are especially valuable in FPGA-based systems because FPGA designs are vulnerable to intellectual property (IP) thefts and cloning, which PUFs protect against by generating random but device-specific bitstrings. Theoretically, the randomness of PUFs originates from variations in the manufacturing process. PUFs should be free of deterministic variation owing to the systematic bias among all chips of the same model. Correspondingly, one of the major challenges for FPGA-based PUFs is the difficulty of avoiding systematic bias between nominally matched delays in competing paths. In this paper, a deep investigation into the LUT structure on a Xilinx FPGA was conducted. Based on the investigation findings, a compact PUF design based on programmable look-up table paths is proposed. The proposed intertwined structure and the novel 2-phase, 2-pass scheme significantly reduced the impact of systematic biases in the Xilinx FPGA LUT. The proposed PUFs exploit random variations in LUTs, thus exhibiting very good uniformity and uniqueness among the generated bitstrings.

15-40% of non-small cell lung cancer (NSCLC) patients harbor epidermal growth factor receptor (EGFR)-sensitizing mutations. Tyrosine kinase inhibitors (TKIs) provide significant clinical benefit in this population, yet all patients will ultimately progress. Liquid biopsy can reliably identify somatic tumor-associated EGFR mutations in plasma. This study aimed to assess the feasibility and value of the quantitative assessment of EGFR driver mutations in plasma in EGFR-mutated NSCLC patients treated with EGFR-TKIs as a tool to evaluate therapeutic response to TKIs and monitor for disease progression. The study included 136 patients with tissue biopsy-confirmed EGFR-sensitizing, mutation-positive lung adenocarcinoma with plasma collected prior to TKI treatment and at least two post-initiation TKI treatment/follow-up blood samples. Plasma samples were tested with the cobas® EGFR Mutation Test v2 (cobas EGFR Test), and semi-quantitative index (SQI) values for each identified mutation were reported by the assay software. The most common baseline EGFR mutations detected in tissue were L858R (53.7%) and exon 19 deletion (39.7%). Plasma cell-free DNA analysis detected EGFR mutations in 74% of the baseline samples. Objective response rate by RECIST 1.1 was achieved in 72% of patients, while 93% had a molecular response (defined as disappearance of the EGFR mutation from plasma). 83% of patients had molecular progression (MP; 1.5X SQI increase or new T790M mutation), and 82% who had a clinical response had clinical progression. On average, MP occurred 42 days prior to clinical progression. Patients who progressed while on first-line TKI showed MP of the original EGFR-sensitizing mutations prior to the emergence of a T790M mutation, which was detected in 27% of the EGFR plasma-positive patients. Longitudinal monitoring of EGFR mutational load in plasma is feasible and can predict both response and clinical progression in EGFR-mutated NSCLC patients treated with EGFR-TKIs, as well as detect treatment-emergent EGFR mutations.

Prestress anchor beams are an important reinforcement method for underground engineering and rock slopes, and they are crucial for maintaining the stability of civil engineering structures. In this study, the computational formula of superimposed stress of soil underlying an anchor beam was proposed in this paper, based on the assumption that the anchor beam is completely rigid and the prestress of the anchor cable is acting on soil in the form of a strip uniform load. By considering the anisotropy and strength nonhomogeneity of the saturated soft clay, the failure envelopes of the soil and the maximum effective depth underlying the anchor beam were obtained by the D-P yield criterion suitable for soft clay analysis. Furthermore, the experimental comparisons with the previous findings were used to validate the proposed approach. The proposed method was valid to assess the maximum effective depth. Considering the influence of the factors on the failure envelopes of soil, a parametric study was carried out to optimize the design of the prestressed anchor cable. The findings of this study provide a theoretical basis for designing prestressed anchor cables; these can also be used to predict the response of prestressed anchor cables as well as to optimize the design of the cables, such as the anchorage length of cable and grouting radius.

Abstract We construct gray soliton configurations, which move at constant speeds, in holographic superfluids for the first time. Since there should be no dissipation for a moving soliton to exist, we use the simplest holographic superfluid model at zero temperature, considering both the standard and alternative quantizations. For comparison purpose, we first investigate black solitons in the zero temperature holographic superfluids, which are static configurations. Then we focus on the numerical construction of gray solitons under both quantizations, which interpolate between the (static) black solitons and sound waves (moving at the speed of sound). Interestingly, under the standard quantization, a peculiar oscillation of the soliton configurations is observed, very much resembling the Friedel oscillation in fermionic superfluids at the BCS regime. Some implications and other aspects of the soliton configurations are also discussed.

Molecular dynamics (MD), grand canonical Monte Carlo (GCMC) and ideal adsorbed solution theory (IAST) were used to study the structures and gas adsorption properties of MIL-53(M)[M=Cr, Fe, Sc, Al] metal organic framework (MOF) materials. The results show that the volumes of those MOF materials increase significantly at high temperature. By analyzing the adsorption isotherms, we found that the temperature had a paramount effect on the gas adsorption behaviors of these MOF materials. For MIL-53(Cr), the orders of the quantities of adsorbed gases were CH4>N2>CO2>H2S, CH4>H2S>CO2>N2 and CH4>CO2>H2S>N2 at 100K, 293K and 623K, respectively. We also calculated the adsorption of several combinations of two gases by MIL-53(Cr) at 293K, the results indicate that the material had selective adsorption of CH4 over CO2, H2S and N2. Our calculations provide microscopic insights into the gas adsorption performances of these MOFs and may further guide the practice of gas separation.