Study on the Rough-set-based Clustering Algorithm for Sensor Networks

The traditional clustering algorithm is a very typical level routing algorithm in wireless sensor networks (WSN). On the basis of the classical LEACH (Low Energy Adaptive Clustering Hierarchy) algorithm, this paper proposes an energy efficient clustering algorithm in WSN. Through the introduction of rough set, the new algorithm mainly introduces how to confirm an optimized strategy to choose the cluster head effectively by the simplified decision table. That is to say, by discrete normalized data preprocessing of attribute value, getting discretization decision table. Finally, the results from simulated experiments show that the clustering algorithm based on rough set theory can optimize the clustering algorithm in network data. That is to say, the rough-set-based clustering algorithm can effectively choose the cluster head, balance the energy of the nodes in the cluster and prolong the lifetime of sensor networks

Environmental Protection and Economic Growth: An Optimal Pollution Controlling Model

Environmental protection against pollution has become a common issue faced by the whole world. In the case of the international cooperation on controlling the environmental pollution, the developing and developed countries have different understanding on the principle of “common but differentiated responsibilities”. This paper has set up an optimal pollution controlling model for the developing and developed countries to incorporate environmental protection and economic growth. Based on a dynamic differential game, we find that the increasing environmental expenditure of developed countries in the initial stage of the economic growth path of the developing country can stimulate more international cooperation on pollution controlling. The developing and developed countries can control the environment pollution without significant loss of social welfare

Environmental Protection and Economic Growth: An Optimal Pollution Controlling Model

Environmental protection against pollution has become a common issue faced by the whole world. In the case of the international cooperation on controlling the environmental pollution, the developing and developed countries have different understanding on the principle of “common but differentiated responsibilities”. This paper has set up an optimal pollution controlling model for the developing and developed countries to incorporate environmental protection and economic growth. Based on a dynamic differential game, we find that the increasing environmental expenditure of developed countries in the initial stage of the economic growth path of the developing country can stimulate more international cooperation on pollution controlling. The developing and developed countries can control the environment pollution without significant loss of social welfare

Effect of counter-rotating fan’s speed matching on stall inception and characteristics of tip clearance flow

In order to study the effect of speed matching on behavior of tip clearance flow and its possible link to stall inception in counter-rotating fan, the Reynolds-averaged Navier-Stokes equations are solved by the numerical method in conjunction with a SST turbulence model, the effect of speed matching on performance and stability margin are investigated, so are the difference of the tip clearance flow in different speed matching. Furthermore, the effect of speed matching on behavior of tip clearance flow and its possible link to stall inception are investigated. Research results show that: when the rotational speed of Rotor 2 is less than that of Rotor 1, with the decrease of rotational speed of Rotor 2 has no notable effect on tip clearance flow fields of the two rotors, therefore offset of stalling boundary is minor and strong blockage effect is observed in Rotor 1; when the rotational speed of Rotor 1 is less than that of Rotor 2, decrease of rotational speed of Rotor 1 show significant effect on the two rotors, which leads to major offset of stalling boundary, tip leakage flow performance of Rotor 1 improved, while that of Rotor 2 weakened and large blockage area occurs. By comparison, speed variation of Rotor 1 has more effect on stalling boundary of counter-rotating fan

Numerical study on aerodynamic noise performances of axial spacing in a contra-rotating axial fan

In order to study the effect of axial spacing on behaviors of aerodynamic performance and aerodynamic noises in a contra-rotating fan, the steady/unsteady Reynolds-averaged Navier-Stokes equations are solved by the numerical method in conjunction with a SST turbulence model, and the effects of axial spacing on performance and aerodynamic characteristics are investigated. Furthermore, BEM is adopted to compute the radiation noise of the contra-rotating fan caused by unsteady pressure fluctuations. The results show that axial spacing is an important factor which can affect the aerodynamic performance of contra-rotating fan. As a whole, the effect of axial spacing on the blade loading of Rotor 2 is significantly greater than that of Rotor 1. For Rotor 2, the smaller axial spacing leads to the large secondary flow loss, and the larger axial spacing leads to the strong mixing loss. With the increase of axial spacing, the radiation noise at the characteristic frequency decreases, but showed different changing degrees. With consideration of the aerodynamic performance and aerodynamic noises of the contra-rotating fan, the optimal comprehensive performance appears at the axial spacing of 0.5 chord

Using hyperhomocysteinemia and body composition to predict the risk of non-alcoholic fatty liver disease in healthcare workers

PurposeThis study investigated associations between serum homocysteine levels, body composition, and the probability of having nonalcoholic fatty liver disease (NAFLD) in Chinese healthcare workers.Patients and MethodsA total of 4028 healthcare workers were enrolled in this study, and all underwent a physical examination. Body composition was measured using multifrequency bioelectrical impedance analysis.ResultsThere were 1507 NAFLD patients (72.26% male, 27.74% female) and 2521 controls (39.83% male, 60.17% female). Body mass index (BMI), waistline, neck-circumference (NC), abdominal visceral fat area (AVFA), total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), glucose (Glu), homocysteinemia (hcy) were higher in the NAFLD group than controls. Additionally, the skeletal-muscle was associated with a lower risk of NAFLD, whereas BMI, waistline, NC, hyperhomocysteinemia (HHcy) were associated with a higher risk of NAFLD. The best NC cut-off point for NAFLD was 34.45 cm (sensitivity 83.3% and specificity 83.9%) in women with HHcy, and the best skeletal-muscle content cut-off point for NAFLD was 41.335% (sensitivity 74.2% and specificity 65.6%) in men with HHcy.ConclusionInteractions between skeletal-muscle content, NC, and HHcy may affect the incidence of NAFLD in healthcare workers. This may provide a novel approach for diagnosing NAFLD