Application of a Multi-Satellite Dynamic Mission Scheduling Model Based on Mission Priority in Emergency Response.

Emergency observations are missions executed by Earth observation satellites to support urgent ground operations. Emergency observations become more important for meeting the requirements of highly dynamic and highly time-sensitive observation missions, such as disaster monitoring and early warning. Considering the complex scheduling problem of Earth observation satellites under emergency conditions, a multi-satellite dynamic mission scheduling model based on mission priority is proposed in this paper. A calculation model of mission priority is designed for emergency missions based on seven impact factors. In the satellite mission scheduling, the resource constraints of scheduling are analyzed in detail, and the optimization objective function is built to maximize the observation mission priority and mission revenues, and minimize the waiting time for missions that require urgency for execution time. Then, the hybrid genetic tabu search algorithm is used to obtain the initial satellite scheduling plan. In case of the dynamic arrival of new emergency missions before scheduling plan releases, a dynamic scheduling algorithm based on mission priority is proposed to solve the scheduling problem caused by newly arrived missions and to obtain the scheduling plan of newly arrived missions. A simulation experiment was conducted for different numbers of initial missions and newly arrived missions, and the scheduling results were evaluated with a model performance evaluation function. The results show that the execution probability of high-priority missions increased because the mission priority was taken into account in the model. In the case of more satellite resources, when new missions dynamically arrived, the satellite resources can be reasonably allocated to these missions based on the mission priority. Overall, this approach reduces the complexity of the dynamic adjustment and maintains the stability of the initial scheduling plan.

A Study for Texture Feature Extraction of High-Resolution Satellite Images Based on a Direction Measure and Gray Level Co-Occurrence Matrix Fusion Algorithm.

To address the problem of image texture feature extraction, a direction measure statistic that is based on the directionality of image texture is constructed, and a new method of texture feature extraction, which is based on the direction measure and a gray level co-occurrence matrix (GLCM) fusion algorithm, is proposed in this paper. This method applies the GLCM to extract the texture feature value of an image and integrates the weight factor that is introduced by the direction measure to obtain the final texture feature of an image. A set of classification experiments for the high-resolution remote sensing images were performed by using support vector machine (SVM) classifier with the direction measure and gray level co-occurrence matrix fusion algorithm. Both qualitative and quantitative approaches were applied to assess the classification results. The experimental results demonstrated that texture feature extraction based on the fusion algorithm achieved a better image recognition, and the accuracy of classification based on this method has been significantly improved.

[Research on the Tomato Metacaspase Protein Interactions with Ca2+ by Spectroscopy and Molecular Probe].

Metacaspases are cysteine-dependent proteases found in protozoa, fungi and plants and are distantly related to metazoan caspases. Most of MCPs activation are the calcium dependent, but the mechanisms are still unknown. Based on the techniques of CD spectroscopy, fluorescence spectroscopy, and Terbium Stains-all probe, we selected three purified recombinant proteins from key residues mutated in tomato metacaspase (LeMCA1), including conserved catalytic site (C139A) mutant, N-sequenced cleaved site (K223G) mutant and the predicted Ca2+ binding sites (D116A/D117A) mutant, to explore the interaction mechanism of LeMCA1 and Ca2+. CD spectroscopy and Stains-all probe results suggested that the intense binding does not exist between LeMCA1 and Ca2+ as well as Ca2+ has little effect on the secondary structure of LeMCA1. However, fluorescence spectroscopy and Tb3+ probe results showed that Ca(2+)-induced the changes occur in the tertiary structure of LeMCA1, which contributes to the activation of zymogen. In addition, predicted Ca2+ binding residues, Asp-116 and Asp117, are the key sites resporisible for the Ca2+ interaction with LeMCA1, and the loss of these two residues resulted in decreased interaction. Our data firstly provided insight on the mechanism of the interaction between Ca2+ and recombinant purified Solanaceae type II metacaspase by spectroscopy and molecular probe techniques. Combined the results we got before from sequence-alignment and sites-mutation, the key residues Asp-116 and Asp117 affect the Ca(2+)-induced the changes of LeMCA1 tertiary structure. Our data provided information for the further biochemical and crystal assays of LeMCA1.