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With the continuous progress of military technology, unmanned aerial vehicles have been more and more widely used in military operation and play an increasingly important role. The collaborative operational mode of manned/unmanned aerial vehicles will surely become an important operational mode in the future. According to the application of unmanned aerial vehicles in the collaborative operational system, the manned/unmanned aerial vehicles collaborative operational architecture is constructed, and the passive centralized, semi-active distributed and resident distributed collaborative operational modes of manned/unmanned aerial vehicles are studied, and key technologies for supporting future manned/unmanned aerial vehicles collaborative operation are proposed. It is of great practical and theoretical significance to enhance the capability of collaborative operation.

A common azo dye, Reactive Red 195 (RR195), is widely used in the printing and dyeing industry. Due to the complicated composition of RR195, how to degrade it has aroused great interest from resear...

Hierarchically porous carbons (HPCs), with large specific surface area, abundant porous channels and adequate anchor points, act as one type of ideal carbon supports for the preparation of single-atom electrocatalysts. In this study, the blood plasma-derived HPC with an interconnected porous framework is constructed via a generated-template method, with the formation of ZnS nanoparticles from the abundant disulfide bonds (–S–S–) in serum albumin. After the thermal activation with heme-containing molecules (also from the bovine-blood biowaste), the HPC exhibits high-exposure and low-spin-state Fe(II)–N4 atomic active sites, and thereby presents a superior oxygen reduction reaction activity (the half wave potential of 0.87 V) and excellent stability (a 4 mV negative shift after 3000 potential cycles), even comparable with the benchmark Pt/C. This work delivers a new insight into the design and synthesis of porous carbons and carbon-based electrocatalysts to develop bio-derived materials in the field of clean energy conversion and storage.

Environmental changes induced by ongoing anthropogenic activities have caused severe lake degradation. Because of the lack of long-term records, few studies have investigated the change in Wuhan lakes, and the effect of human activities on regional lake changes prior to 1973 has not been systematically studied yet. Therefore, in this study, historical maps and Landsat images were combined to track these changes from the 1920s to 2015. Three phases could be identified over the nearly 100-year study period. The most dramatic lake reduction (−21.53 km2 yr−1) occurred during Phase II (1950s–1980s) rather than Phase III (after the 1980s), as indicated by previous studies; the decreased lake area in Phase II was almost double that in Phase III. This reduction could be attributed to major hydraulic engineering projects during Phase II based on the watershed-scale analysis. In addition, land-use conversion over the past 45 years was used to quantify the impact of human exploitation on lakes. The shrinkage of lakes was predominately driven by agricultural activities, such as reclamation (39.2%) and aquaculture development (29.0%), and urbanization was a secondary driving force (19.8%), despite the rapid economic development of Wuhan. This study therefore provides a practical guide for lake protection in other areas similar to Wuhan.

Fault or health condition prediction of the complex systems has attracted more attention in recent years. The complex systems often show complex dynamic behavior and uncertainty, which makes it difficult to establish a precise physical model. Therefore, the time series of complex system is used to implement prediction in practice. Aiming at time series online prediction, we propose a new method to improve the prediction accuracy in this paper, which is based on the grey system theory and incremental learning algorithm. In this method, the accumulated generating operation (AGO) with the raw time series is taken to improve the data quality and regularity firstly; then the prediction is conducted by a modified LS-SVR model, which simplifies the calculation process with incremental learning; finally, the inverse accumulated generating operation (IAGO) is performed to get the prediction results. The results of the prediction experiments indicate preliminarily that the proposed scheme is an effective prediction approach for its good prediction precision and less computing time. The method will be useful in actual application.

Using multi temporal satellite images of remote sensing,wetland information was extracted by decision tree classification method combined with field surveying and four Lake Dongting's wetland type distribution maps were drawn out.This paper mainly analyzes the dynamic characteristics of wetland vegetation,driving factors and their influence on the wetland ecosystem in this region.Results show that vegetation community distribution and proportion changed obviously.In the past 17 a,forest area increased by 367.88 km2 at a rate of 1127.51%.The forest area extended to main part of beaches and became the main vegetation type of Lake Dongting.Reed area decreased by 44.09 km2,while sedge land area increased by 2.99 km2,with change rate of-5.80% and 0.40%,respectively.This change resulted from both natural environment evolution and human activities.The destruction of natural wetland vegetation,especially planted reed and poplar,destroyed the structure and function of Lake Dongting wetland ecosystem.In order to protect the Lake Dongting wetland effectively,we must rationally exploit bottomland resource,protect natural wetland vegetation and make good management on shoal forestation.

The vascular flora in Lake Erhai wetland was investigated from May to December in 2009,and we found 145 species belonged to 108 genera in 47 families,including 15 trees and shrubs,75 hygrophytes,15 emergent macrophytes,26 submerged macrophytes,7 floating-leaved and floating plants,respectively.The wetland held 15 communities,such as Salix cavaleriei,Zizania latifolia,Trapa natans and Potamogeton maackianus comm.Aquatic vegetation covered about 8% of total water area of the lake,and the average species number and biomass were 9 and 12.5 kg(FW)/m2 in exploring sites,respectively.Richness index of Margalef species was 1.8706 in submerged macrophyte zone.Analysis with combinations of existing data indicated that plant diversity increased after enhancing management and lakeshore wetland restoration in the recent ten years and improved the situation of plant diversity decreasing in the northern lake.However,many problems still exist in the lakeshore wetland,such as narrow lakeshore areas,monotonous emergent macrophyte in the community,low coverage of aquatic vegetation,and the inherent flora ingredient to be restored.In order to improve functions of the lakeshore wetland,to increase water transparency and to advance the coverage of aquatic vegetation,we strongly suggest constructing the buffer areas.

Soil erosion by water is a serious problem all over the world. In China, about 1 790 000 km2 of land suffers from water erosion, which accounts for 18.3% of China’s total area. This study was conducted in the Liao (潦) watershed in Jiangxi (江西) Province to assess annual soil erosion and sediment yield using the Universal Soil Loss Equation (USLE). A geographic information system (GIS) was used to generate maps of the USLE factors, which include rainfall erosivity (R), soil erodibility (K), slope length and steepness (LS), cover (C), and conservation practice (P) factors. By integrating these factors in a GIS, a spatial distribution of soil erosion over the Liao watershed was obtained. The soil erosion was found to vary from nil for flat and well-covered areas to more than 500 t/ha/a in mountainous places with sparse vegetation. The average soil erosion is 18.2 t/ha/a with a standard deviation of 109.3 t/ha/a. The spatial distribution of erosion classes was estimated. About 39.5% of the watershed is under the tolerant erosion rate, and 60.5% of the study area experienced erosion to different extents. A spatially distributed sediment delivery ratio (SDR) module was developed to account for soil erosion and deposition. It was found that the SDR value at the outlet of the Liao watershed was 0.206, and the sediment yield was 1.32 million t/a, which was 20% higher than the measured sediment. The results can be used to identify the soil erosion hot spots and develop the best soil erosion management practices and help estimate the quantity of soil that was transported into the downstream Poyang (鄱阳) Lake.

Researching on chaos-based image encryption scheme is becoming increasingly popular; unfortunately, most of the algorithms proposed provide poor security because of their failure to resist attack. A new digital image encryption scheme based on variable parameters double logistic systems is presented. The subkey sequences are generated after optimizing and adjusting from the chaotic maps which have certain relation to the plaintext, which enhances the security of the cryptosystem. The analysis and the simulation results imply this encryption scheme possesses the features of large key spaces, sensitive key dependence, and good security. Especially this algorithm is able to effectively resist traditional attack.

Collaborative virtual environment (CVE) systems support many users to share a virtual world and to do collaborative work and multiple-server architectures are widely used in which multiple servers are deployed and each server handles a partition of the virtual world. One of the key issues in the design of scalable CVE systems based on the multiple-server architecture is partitioning problem. In this paper, a task-based clustering method is proposed for solving the partitioning problem in CVE systems. Because of the uncertainty of the number of users in the CVE system, using the task-based clustering method, the virtual world is divided into the collaborative task areas according to the current number of users in the CVE system and each collaborative task area is assigned to a server. Though several experiments, the effectiveness of our proposed method is shown.