Description: IJGI, Vol. 7, Pages 273: Using High-Performance Computing to Address the Challenge of Land Use/Land Cover Change Analysis on Spatial Big Data ISPRS International Journal of Geo-Information doi: 10.3390/ijgi7070273 Authors: Xiaochen Kang Jiping Liu Chun Dong Shenghua Xu Land use/land cover change (LUCC) analysis is a fundamental issue in regional and global geography that can accurately reflect the diversity of landscapes and detect the differences or changes on the earth’s surface. However, a very heavy computational load is often unavoidable, especially when processing multi-temporal land cover data with fine spatial resolution using more complicated procedures, which often takes a long time when performing the LUCC analysis over large areas. This paper employs a graph-based spatial decomposition that represents the computational loads as graph vertices and edges and then uses a balanced graph partitioning to decompose the LUCC analysis on spatial big data. For the decomposing tasks, a stream scheduling method is developed to exploit the parallelism in data moving, clipping, overlay analysis, area calculation and transition matrix building. Finally, a change analysis is performed on the land cover data from 2015 to 2016 in China, with each piece of temporal data containing approximately 260 million complex polygons. It took less than 6 h in a cluster with 15 workstations, which was an indispensable task that may surpass two weeks without any optimization.

Description: Energies, Vol. 11, Pages 679: Thermal Performance of Microencapsulated Phase Change Material (mPCM) in Roof Modules during Daily Operation Energies doi: 10.3390/en11030679 Authors: Qi Zhou Pin-Feng Liu Chun-Ta Tzeng Chi-Ming Lai This study combines microencapsulated phase change materials (mPCMs) (core material: paraffin; melting points: 37 and 43 °C) and aluminum honeycomb boards (8 mm core cell) to form mPCM roof modules and investigates their heat absorption and release performances, as well as their impact on indoor heat gain by conducting experiments over a 24-h period, subject to representative weather. The outdoor boundary conditions of the module are hourly sunlight and nighttime natural cooling; on the indoor side of the module, the conditions are daytime air conditioning and nighttime natural cooling. The results indicate that compared to a roof module with a 43 °C melting point mPCM, the roof module with a 37 °C melting point mPCM had improved peak load-shifting capacity, but had a slightly increased indoor heat gain. The mPCMs in both roof modules were successfully cooled during the night, returning to their initial state, to begin a new thermal cycle the next day.

Description: Sensors, Vol. 18, Pages 3: Implementation of Wi-Fi Signal Sampling on an Android Smartphone for Indoor Positioning Systems Sensors doi: 10.3390/s18010003 Authors: Hung-Huan Liu Chun Liu Collecting and maintaining radio fingerprint for wireless indoor positioning systems involves considerable time and labor. We have proposed the quick radio fingerprint collection (QRFC) algorithm which employed the built-in accelerometer of Android smartphones to implement step detection in order to assist in collecting radio fingerprints. In the present study, we divided the algorithm into moving sampling (MS) and stepped MS (SMS), and describe the implementation of both algorithms and their comparison. Technical details and common errors concerning the use of Android smartphones to collect Wi-Fi radio beacons were surveyed and discussed. The results of signal sampling experiments performed in a hallway measuring 54 m in length showed that in terms of the amount of time required to complete collection of access point (AP) signals, static sampling (SS; a traditional procedure for collecting Wi-Fi signals) took at least 2 h, whereas MS and SMS took approximately 150 and 300 s, respectively. Notably, AP signals obtained through MS and SMS were comparable to those obtained through SS in terms of the distribution of received signal strength indicator (RSSI) and positioning accuracy. Therefore, MS and SMS are recommended instead of SS as signal sampling procedures for indoor positioning algorithms.

Description: IJERPH, Vol. 15, Pages 1082: Location of Femoral Fractures in Patients with Different Weight Classes in Fall and Motorcycle Accidents: A Retrospective Cross-Sectional Analysis International Journal of Environmental Research and Public Health doi: 10.3390/ijerph15061082 Authors: Meng-Wei Chang Hang-Tsung Liu Chun-Ying Huang Peng-Chen Chien Hsiao-Yun Hsieh Ching-Hua Hsieh Background: This study aimed to determine the incidence of femoral fracture location in trauma patients with different weight classes in fall and motorcycle accidents. Methods: A total of 2647 hospitalized adult patients with 2760 femoral fractures from 1 January 2009 to 31 December 2014 were included in this study. Femoral fracture sites were categorized based on their location: proximal femur (type A, trochanteric; type B, neck; and type C, head), femoral shaft, and distal femur. The patients were further classified as obese (body mass index [BMI] of ≥30 kg/m2), overweight (BMI of <30 but ≥25 kg/m2), normal weight (BMI of <25 but ≥18.5 kg/m2), and underweight (BMI of <18.5 kg/m2). Odds ratios and 95% confidence intervals of the incidences of femoral fracture location were calculated in patients with different weight classes in fall or motorcycle accidents, and they were then compared with those in patients with normal weight. p values of <0.05 were considered statistically significant. Results: Most of the fractures sustained in fall accidents presented in the proximal type A (41.8%) and type B (45.3%) femur, whereas those sustained in motorcycle accidents involved the femoral shaft (37.1%), followed by the distal femur (22.4%) and proximal type A femur (21.2%). In fall accidents, compared with normal-weight patients, obese and overweight patients sustained lower odds of risk for proximal type B fractures but higher odds of risk for femoral shaft and distal femoral fractures. In motorcycle accidents, compared with normal-weight patients, obese patients sustained lower odds of risk for proximal type B fractures but no difference in odds of risk for femoral shaft and distal femoral fractures. Overweight and underweight patients who sustained fractures in a motorcycle accident did not have different fracture location patterns compared with normal-weight patients. Conclusions: This study revealed that femoral fracture locations differ between fall and motorcycle accidents. Moreover, greater soft tissue padding may reduce impact forces to the greater trochanteric region in obese patients during fall accidents, and during motorcycle accidents, the energy transmitted and the point of impact may dominantly determine the location of femoral fractures.

Description: Sustainability, Vol. 10, Pages 733: A Novel Integrated Approach for Green Supplier Selection with Interval-Valued Intuitionistic Uncertain Linguistic Information: A Case Study in the Agri-Food Industry Sustainability doi: 10.3390/su10030733 Authors: Hua Shi Mei-Yun Quan Hu-Chen Liu Chun-Yan Duan With strengthening global consciousness of environmental protection, green supply chain management plays an increasingly important role in modern enterprise production operation management. A critical means to implement green supply chain management is incorporating environmental requirements into the supplier selection practices. In this paper, we put forward a novel integrated approach by using interval-valued intuitionistic uncertain linguistic sets (IVIULSs) and grey relational analysis (GRA)-technique for order preference by similarity to ideal solution (TOPSIS) method for the evaluation and selection of green suppliers. First, various qualitative assessments of alternatives provided by decision makers are described by the IVIULSs. Then, the GRA-TOPSIS method is extended and employed to prioritize the alternative suppliers. The proposed model can handle the uncertainty and fuzziness of decision makers’ subjective evaluations more easily and get a more realistic and accurate ranking of green suppliers. Finally, an illustrative example in the agri-food industry is presented to verify the proposed green supplier selection model and demonstrate its practicality and effectiveness.

Description: A global optimization algorithm for solving generalized geometric programming (GGP) problem is developed based on a new linearization technique. Furthermore, in order to improve the convergence speed of this algorithm, a new pruning technique is proposed, which can be used to cut away a large part of the current investigated region in which the global optimal solution does not exist. Convergence of this algorithm is proved, and some experiments are reported to show the feasibility of the proposed algorithm.

Description: A global optimization algorithm for solving generalized geometric programming (GGP) problem is developed based on a new linearization technique. Furthermore, in order to improve the convergence speed of this algorithm, a new pruning technique is proposed, which can be used to cut away a large part of the current investigated region in which the global optimal solution does not exist. Convergence of this algorithm is proved, and some experiments are reported to show the feasibility of the proposed algorithm.

Description: This paper investigates the performance of a fault-tolerant four-switch three-phase (FSTP) grid-side converter (GSC) in a doubly-fed induction generator-based wind turbine (DFIG-WT). The space vector pulse width modulation (SVPWM) technique is simplified and unified duty ratios are used for controlling the FSTP GSC. Steady DC-bus voltage, sinusoidal three-phase grid currents and unity power factor are obtained. In addition, the balance of capacitor voltages is accomplished based on the analysis of current flows at the midpoint of DC bus in different operational modes. Besides, external disturbances such as fluctuating wind speed and grid voltage sag are considered to test its fault-tolerant ability. Furthermore, the effects of fluctuating wind speed on the performance of DFIG-WT system are explained according to an approximate expression of the turbine torque. The performance of the proposed FSTP GSC is simulated in Matlab/Simulink 2016a based on a detailed 1.5 MW DFIG-WT Simulink model. Experiments are carried out on a 2 kW platform by using a discrete signal processor (DSP) TMS320F28335 controller to validate the reliability of DFIG-WT for the cases with step change of the stator active power and grid voltage sag, respectively.