ALBERT

Description: Urban areas play a very important role in global climate change. There is increasing need to understand global urban areas with sufficient spatial details for global climate change mitigation. Remote sensing imagery, such as medium resolution Landsat daytime multispectral imagery and coarse resolution Defense Meteorological Satellite Program/Operational Linescan System (DMSP/OLS) nighttime light imagery, has provided a powerful tool for characterizing and mapping cities, with advantages and disadvantages. Here we propose a framework to merge cloud and cloud shadow-free Landsat Normalized Difference Vegetation Index (NDVI) composite and DMSP/OLS Night Time Light (NTL) to characterize global urban areas at a 30 m resolution, through a Normalized Difference Urban Index (NDUI) to make full use of them while minimizing their limitations. We modify the maximum NDVI value multi-date image compositing method to generate the cloud and cloud shadow-free Landsat NDVI composite, which is critical for generating a global NDUI. Evaluation results show the NDUI can effectively increase the separability between urban areas and bare lands as well as farmland, capturing large scale urban extents and, at the same time, providing sufficient spatial details inside urban areas. With advanced cloud computing facilities and the open Landsat data archives available, NDUI has the potential for global studies at the 30 m scale.

Description: Winter soil respiration (Rs) is becoming a significant component of annual carbon budgets with more warming in winter than summer. However, little is known about the controlling mechanisms of winter Rs in dryland. We made continuous measurements of Rs in four microsites (non-crust (BS), lichen (LC), moss (MC), and a mixture of moss and lichen (ML)) in a desert shrub-land ecosystem northern China, to investigate the causes of Rs dynamics in winter. The mean winter Rs ranged from 0.10 to 0.17 µmol CO2 m−2·s−1 across microsites, with the highest value in BS. Winter Q10 (known as the increase in respiration rate per 10 °C increase in temperature) values (2.8–19) were much higher than those from the growing season (1.5). Rs and Q10 were greatly enhanced in freeze-thaw cycles compared to frozen days. Diurnal patterns of Rs between freeze-thaw and frozen days differed. Although the freeze-thaw period was relatively short, its cumulative Rs contributed significantly to winter Rs. The presence of biocrust might induce lower temperature, thus having fewer freeze-thaw cycles relative to bare soil, leading to the lower Rs for microsites with biocrusts. In conclusion, winter Rs in drylands was sensitive to soil temperature (Ts) and Ts-induced freeze-thaw cycles. The temperature impact on Rs varied among soil cover types. Winter Rs in drylands may become more important as the climate is continuously getting warmer.

Description: Illegal logging, with its related trade of illegally harvested timber, is one of the main environmental and economic problems worldwide. Eliminating illegal timber consumption and production are two practical means to reduce illegal logging. However, the problem of determining which of the two means is more economical remains to be analyzed. In this study, an input–output analysis was conducted to evaluate the consumption and production of illegal timber in different countries. The Global Forest Products Model (GFPM) was employed to analyze the effects of eliminating illegal timber consumption and production on the added value of the forest sector at global and national levels. Results indicated that eliminating illegal timber production is more economical than eliminating consumption at the global level. The former is estimated to decrease the added value of the global forest sector only by 3.37% compared to 7.31% by the latter in 2030. Eliminating the production of illegal timber will result in uneven distribution of social wealth in the forest sector, and will pass the cost of reducing illegal logging onto developing countries. Developed countries would gain more added value and market scale than the global average, whereas developing countries would suffer a loss if illegal timber production is eliminated. Hence, developed countries are encouraged to provide financial support to help developing countries reduce illegal logging.

Description: Many intelligent transportation system applications require accurate, reliable, and continuous vehicle positioning. How to achieve such positioning performance in extended GPS-denied environments such as tunnels is the main challenge for land vehicles. This paper proposes a hybrid multi-sensor fusion strategy for vehicle positioning in tunnels. First, the preliminary positioning algorithm is developed. The Radio Frequency Identification (RFID) technology is introduced to achieve preliminary positioning in the tunnel. The received signal strength (RSS) is used as an indicator to calculate the distances between the RFID tags and reader, and then a Least Mean Square (LMS) federated filter is designed to provide the preliminary position information for subsequent global fusion. Further, to improve the positioning performance in the tunnel, an interactive multiple model (IMM)-based global fusion algorithm is developed to fuse the data from preliminary positioning results and low-cost in-vehicle sensors, such as electronic compasses and wheel speed sensors. In the actual implementation of IMM, the strong tracking extended Kalman filter (STEKF) algorithm is designed to replace the conventional extended Kalman filter (EKF) to achieve model individual filtering. Finally, the proposed strategy is evaluated through experiments. The results validate the feasibility and effectiveness of the proposed strategy.

Description: Vehicle to Grid technology allows the batteries of electric vehicles to operate as energy storage elements for renewable energy power systems. The Z-Source inverter is a new and attractive topology for the power electronics interface. In this paper, the equivalent DC-link voltage ripple of a single-phase Z-Source inverter for Vehicle to Grid applications is analyzed in this paper before deriving a general design approach for the Z-Source network. These theoretical findings, and design rule for a Z-Source network have been confirmed by computer simulations and a laboratory-implemented prototype.

Description: Spinning reserve allocation is a critical problem for active power dispatch with large-scale wind power penetration. A risk-based reserve allocation method that accounts multiple control sub-area coordination is given in this paper. And a multi-objective optimization model is constructed to schedule the spinning generation reserve for online active power dispatch. A fuzzy optimization method is used to transform the multi-objective optimization problem into a single-objective optimization one. The relationship between loss of load expectation and spinning reserve is also derived. And a particle swarm optimization (PSO) method is employed to provide a numerical solution to the problem. Numerical tests on IEEE RTS system are also given to validate the proposed method.

Description: Vehicle to Grid technology allows the batteries of electric vehicles to operate as energy storage elements for renewable energy power systems. The Z-Source inverter is a new and attractive topology for the power electronics interface. In this paper, the equivalent DC-link voltage ripple of a single-phase Z-Source inverter for Vehicle to Grid applications is analyzed in this paper before deriving a general design approach for the Z-Source network. These theoretical findings, and design rule for a Z-Source network have been confirmed by computer simulations and a laboratory-implemented prototype.

Description: Ecological and environmental protection is the core content of ecotourism development. A quantitative evaluation of the effects of ecotourism environmental protection (hereinafter referred to as EEP) measures on protected areas is conducive to a deeper understanding of the key issues related to ecotourism development in China, thus providing the theoretical basis for formulating the relevant national policies of sustainable ecotourism development in China. This paper first discusses the evaluation index system and then establishes an index evaluation model of EEP measures and their effects on protected areas. Using surveys of more than 1110 protected areas in 27 provinces (autonomous regions or municipalities), we evaluated the EEP measures and their effects from a quantitative and spatial perspective. The completeness of EEP measures for Chinese protected areas was moderately effective, and the implementation status of the protection measures varied with the protection region. The effectiveness of EEP measures in different provinces and regions showed significant differences. The effectiveness decreased from east to west. The evaluation index values of the environmental protection measures displayed a high correlation with the effects of environmental protection on protected areas. The ecological protection measures should be further improved and strengthened according to their regional differences during ecotourism development.

Description: This paper reports a more complete description of the design process of the Center Support Quadruple Mass Gyroscope (CSQMG), a gyro expected to provide breakthrough performance for flat structures. The operation of the CSQMG is based on four lumped masses in a circumferential symmetric distribution, oscillating in anti-phase motion, and providing differential signal extraction. With its 4-fold symmetrical axes pattern, the CSQMG achieves a similar operation mode to Hemispherical Resonant Gyroscopes (HRGs). Compared to the conventional flat design, four Y-shaped coupling beams are used in this new pattern in order to adjust mode distribution and enhance the synchronization mechanism of operation modes. For the purpose of obtaining the optimal design of the CSQMG, a kind of applicative optimization flow is developed with a comprehensive derivation of the operation mode coordination, the pseudo mode inhibition, and the lumped mass twisting motion elimination. The experimental characterization of the CSQMG was performed at room temperature, and the center operation frequency is 6.8 kHz after tuning. Experiments show an Allan variance stability 0.12°/h (@100 s) and a white noise level about 0.72°/h/√Hz, which means that the CSQMG possesses great potential to achieve navigation grade performance.

Description: Sensors, Vol. 18, Pages 2603: Measurement and Isolation of Thermal Stress in Silicon-On-Glass MEMS Structures Sensors doi: 10.3390/s18082603 Authors: Zhiyong Chen Meifeng Guo Rong Zhang Bin Zhou Qi Wei The mechanical stress in silicon-on-glass MEMS structures and a stress isolation scheme were studied by analysis and experimentation. Double-ended tuning forks (DETFs) were used to measure the stress based on the stress-frequency conversion effect. Considering the coefficients of thermal expansion (CTEs) of silicon and glass and the temperature coefficient of the Young’s modulus of silicon, the sensitivity of the natural frequency to temperature change was analyzed. A stress isolation mechanism composed of annular isolators and a rigid frame is proposed to prevent the structure inside the frame from being subjected to thermal stresses. DETFs without and with one- or two-stage isolation frames with the orientations <110> and <100> were designed, the stress and natural frequency variations with temperature were simulated and measured. The experimental results show that in the temperature range of −50 °C to 85 °C, the stress varied from −18 MPa to 10 MPa in the orientation <110> and −11 MPa to 5 MPa in the orientation <100>. For the 1-stage isolated DETF of <110> orientation, the measured stress variation was only 0.082 MPa. The thermal stress can be mostly rejected by a stress isolation structure, which is applicable in the design of stress-sensitive MEMS sensors and actuators.