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Mine environmental geological assessment usually uses the expert subjective assignment to determine the weights of affecting factors, but the mine environmental geological problems are the result of many factors. Each factor is complex on the suitability of the influence factors, and the factors interrelate and restrict each other, so the human factor is of great impact. Take the geological quality evaluation of the mine environment of Shanxi, Shaanxi and Inner Mongolia mining area as an example, this article discusses in detail the process of determining the weights of evaluation factors by using the analytic hierarchy process (AHP), which increases the scientific nature of the assignment and reduces the subjectivity, which achieves satisfactory results.

We should construct a spatial database system for mineral resource reserve in Hebei province based on the database with the application of GIS spatial database technology based on the MapGIS software platform. Combined with the construction process of the database, this paper summarizes the problems and the solutions encountered in the construction of large database, and analyzes some techniques the departments of land and resources often use in basic geographic data to discuss with colleagues to further improve the quality and efficiency of database construction.

Aiming at the problem that the stability of clustering recognition algorithm without any prior information is not enough and the network cluster extraction quality needs to be improved and so on, the original algorithm is improved from the following aspects: The choice of the destination vertex function is added in the random walk; use automatic step number detection method to cancel the original algorithm of random walk steps parameter; add weight of evaluation inter-cluster connection on the original based on cluster extraction conditions; realize the controllable particle size of cluster extraction by introducing the threshold parameter. The test results show that the improved algorithm in terms of anti-jamming in the stability and the clustering quality are higher than the original algorithm.

Cluster network structure is one of the most common topological properties of complex networks and the most important topological attribute, and has the characteristics of the same cluster nodes connected to each other, and the sparse characteristics of the dense clusters interconnected with nodes. To reveal the complex network clustering method of network cluster structure has a very important theoretical significance for the analysis of complex network topology structure, to understand its function, discovering the behavior of the hidden patterns, prediction, and is widely used in social networks, biological networks and the world wide web. This article reviews the research background of the complex network clustering method, research significance, research status at home and abroad as well as the major problems currently facing this new research direction in an attempt to draw a comprehensive and clear outline, to provide a useful reference for researchers of the complex network, data mining, intelligent Web, Bioinformatics and other related fields.

n order to accurately predict the future trend of the stock index, a stock index prediction model (SIPM) is provided. SIPM composed by the following modules: data acquisition module, data preprocessing module, learning modules and forecasting modules. The core of SIPM is the last module which adopts ANN as its predicting model. Based on the historical data of a past period, SIPM can forecast next M days trends. The experiments on daily, weekly and monthly data show that the model is feasible. The key conclusion is that SIPM has good prediction results on low-level time granularity.

Fractured reservoir development process are often faced with the angle wells flooded serious and side wells don’t get the effect of water injection. In order to increase the water flooding sweep efficiency. Profile control plugging is a measure that is frequently used. Traditional plugging program design does not take into account the fluid loss, Program design of the blocking agent dosage is always small, the result is not satisfactory. In this paper, the classic percolation theory is used, seepage equation of the fracture system and matrix system is established, the blocking agent Filtrate analytical solution that considers the different reservoir properties and different blocking agent performance is obtained, that can be used to guide the design of profile control water plugging program and can calculate the best blocking agent dosage. Through the actual implementation of the effect, the proposed method can be more substantial increase in the effect of plugging.

Different overseas oil field development and production projects, have different tax provisions. The contract requires different models for different development strategies. In this paper, the X oilfield abroad, for example, studied the oilfield development to adjust the initial well production line, and the adjustment of the oil field development well later provided the basis for the deployment.

A hierarchical model of survival situational awareness is proposed based on multi-feature fusion, which includes three layers: feature fusion layer, situation assessment layer and comprehensive perception layer. In the feature fusion layer, light-computation features and efficient fusion mechanisms are employed to improve degree of differentiation. Situation assessment layer adopted fusion technology of variable fuzzy set theory to improve the accuracy and objectivity of evaluation. Furthermore, time series of services are introduced to judge the safety states and predict the trends in comprehensive perception layer. Experiments indicate that proposed model is more scientific and more accurate, which is valuable for generalizations and applications.

Major domestic oil fields have entered the period of high water now, however, choosing timing of profile control and water shutoff is always delay, Mostly have to wait until after the adoption of dynamic degradation. This article introduced the concept of early warning that is widely used in military and economic fields to profile control and water shut-off decision-making in high water-cut stage. Combination of actual situation of water shut-off decision-making, Presented a strong adaptive set of Warning signs of indicators, on the basis of the analysis of variation in the warning sighs of indicators, this paper proposed early warning model and processes of profile control and water shut-off. The model not only can give the current degree of a single well, but also can forecast the future degree of change in a period of time, so this modle could provide an effective basis for water shutoff and profile controle decision-makers.

Protein structures generally consist of favorable folding motifs formed by specific arrangements of secondary structure elements. Similar architectures can be adopted by different amino acids sequences, although the details of the structures vary. It has long been known that despite the sequence variability, there is a striking preferential conservation of the hydrophobic character of the amino acids at the buried positions of these folding motifs. Differences in the sizes of the side-chains are accommodated by movements of the secondary structure elements with respect to each other, leading to compact packing. Scanning protein-protein interfaces reveals that similar architectures are also observed at and around their interacting surfaces, with preservation of the hydrophobic character, although not to the same extent.The general forces that determine the origin of the native structures of proteins have been investigated intensively. The major non-bonded forces operating on a protein chain as it folds into a three-dimensional structure are likely to be packing, the hydrophobic effect, and electrostatic interactions. While the substantial hydrophobic forces lead to a compact conformation, they are also nonspecific and cannot serve as a guide to a conformationally unique structure. For the general folding problem, it thus appears that packing is a prime candidate for determining a particular fold. Specific hydrogen-bonding patterns and salt-bridges have also been proposed to play a role. Inspection of protein-protein interfaces reveals that the hallmarks governing single chain protein structures also determine their interactions, suggesting that similar principles underlie protein folding and protein-protein associations. This review focuses on some aspects of protein-protein interfaces, particularly on the architectures and their interactions. These are compared with those present in protein monomers. This task is facilitated by the recently compiled, non-redundant structural dataset of protein-protein interfaces derived from the crystallographic database. In particular, aldiough current view holds that protein-protein interfaces and interactions are similar to those found in the conformations of single-chain proteins, this review brings forth the differences as well. Not only is it logical that such differences would exist, it is these differences that further illuminate protein folding on the one hand and protein-protein recognition on the other. These are also particularly important in considering inhibitor (ligand) design.

The predicted active site of chorismate mutase of baker's yeast Saccharomyces cerevisiaehas been studied by continuum electrostatics, molecular surface/volume calculations, and molecular modeling. Our study shows that despite being subject to an allosteric transition, the enzyme's active‐site pocket neither decreased in volume nor deformed significantly in shape between the active R state and the inactive T state. We find that the polar atmosphere in the pocket is responsible for the enzyme's affinity. A single amino acid, Glu23, can adequately account for the atmospheric variation. This residue swings into the active‐site pocket from the R state to the T state. In the R state, Glu23 on helix H2 doubly pairs with Arg204 and Lys208 of H11, which is packed against H2. In the T state, a slide occurs between H11 and H2 such that Glu23 can no longer interact with Lys208 and competes with Asp24 for interacting with Arg204. Consequently, Glu23 is found in the T state to couple with Arg157, an active‐site residue critical to substrate binding. The tandem sliding of H11 in both monomers profoundly changes the interactions in the dimer interface. The loop between H11 and H12 demonstrates the largest conformational change. Hence, we establish a connection between the allosteric transition and the activity of the enzyme. The conformational change in the transition is suggested to propagate into the active‐site pocket via a series of polar interactions that result in polarity reversal in the active‐site pocket, which regulates the enzyme's activity. Proteins 31:445–452, 1998. © 1998 Wiley‐Liss, Inc.

The structure of the complex of the chorismate mutase from the yeast Saccharomyces cerevisiae with a transition state analog is constructed using a suite of docking tools. The construction finds the best location for the active site in the enzyme, and the best orientation of the analog compound in the active site. The resulting complex shows extensive salt links and hydrogen bonds between the enzyme and the compound, including those mediated by water molecules. A network of polar interactions between amino acid residues is found to solidify the active site of the enzyme. The enzymatic mechanism suggested for a bacterial chorismate mutase, that the active site is by design capable of selecting an active conformer of the substrate, and of stabilizing the transition state, is apparently intact in the yeast enzyme. No direct evidence is found to support an alternative mechanism which involves specific catalytic groups, although the possibility is not eliminated. This finding reinforces the notion of a function being evolutionarily conserved via a common mechanism, rather than via sequential or structural homology.

While there are a number of structurally non-redundant datasets of protein monomers, there is none of protein-protein interfaces. Yet, the availability of such a dataset is expected to provide an added insight into a number of investigations. First and foremost among these is analyzing the interfaces to obtain their prevailing architectures, the forces that account for the protein- protein associations and their packing considerations. Their comparisons with those of the monomers are likely to shed additional light on protein-protein recognition on the one hand and on the folding of the polypeptide chain on the other. Docking simulations are also expected to benefit from the existence of such a dataset. A major stumbling block to the generation of a dataset of interfaces has been that the interface is composed of at least two chains. Furthermore, in the interfaces, each of the chains might be represented by non-contiguous pieces. Their order in the interfaces being compared might be different as well. This discontinuity stems from the definition of an interface. An interface consists of interacting residues between the chains, and those that are in their vicinity in the supporting scaffold, within a certain distance threshold. This necessarily yields unordered fragments, as well as isolated residues. Our novel, efficient, sequence-order-independent structural comparison tech nique is ideally suited to handle the task of the generation of a library of structurally non-redundant protein-protein interfaces. As it is computer- vision based, it views atoms as collections of points in space, disregarding their chain connectivity. In this work, 351 interface-families are created. Comparisons of the interfaces, and separately, of the chains which contribute to them, yield some interesting cases. In one of the cases, while two interfaces are similar, the structure of only one of the two chains is similar between the two complexes. The structure of the second chain of the first complex differs from that of the second chain of the second complex. Here the structure of the cleft in the first chain dictates the specific binding interactions. In another case, while the interfaces in the two complexes are similar, both chains composing them differ between the complexes. Lastly, the chains composing the complexes are similar, but the interfaces are dissimilar, providing a set of data for investigations of the favorable orientations of protein-protein associations.

The predicted active site of chorismate mutase of baker's yeast Saccharomyces cerevisiae has been studied by continuum electrostatics, molecular surface/volume calculations, and molecular modeling. Our study shows that despite being subject to an allosteric transition, the enzyme's active-site pocket neither decreased in volume nor deformed significantly in shape between the active R state and the inactive T state. We find that the polar atmosphere in the pocket is responsible for the enzyme's affinity. A single amino acid, Glu23, can adequately account for the atmospheric variation. This residue swings into the active-site pocket from the R state to the T state. In the R state, Glu23 on helix H2 doubly pairs with Arg204 and Lys208 of H11, which is packed against H2. In the T state, a slide occurs between H11 and H2 such that Glu23 can no longer interact with Lys208 and competes with Asp24 for interacting with Arg204. Consequently, Glu23 is found in the T state to couple with Arg157, an active-site residue critical to substrate binding. The tandem sliding of H11 in both monomers profoundly changes the interactions in the dimer interface. The loop between H11 and H12 demonstrates the largest conformational change. Hence, we establish a connection between the allosteric transition and the activity of the enzyme. The conformational change in the transition is suggested to propagate into the active-site pocket via a series of polar interactions that result in polarity reversal in the active-site pocket, which regulates the enzyme's activity. Proteins 31:445–452, 1998. © 1998 Wiley-Liss, Inc.

We have developed a geometry-based suite of processes for molecular docking. The suite consists of a molecular surface representation, a docking algorithm, and a surface inter-penetration and contact filter. The surface representation is composed of a sparse set of critical points (with their associated normals) positioned at the face centers of the molecular surface, providing a concise yet representative set. The docking algorithm is based on the Geometric Hashing technique, which indexes the critical points with their normals in a transformation invariant fashion preserving the multi-element geometric constraints. The inter-penetration and surface contact filter features a three-layer scoring system, through which docked models with high contact area and low clashes are funneled. This suite of processes enables a pipelined operation of molecular docking with high efficacy. Accurate and fast docking has been achieved with a rich collection of complexes and unbound molecules, including protein-protein and protein-small molecule associations. An energy evaluation routine assesses the intermolecular interactions of the funneled models obtained from the docking of the bound molecules by pairwise van der Waals and Coulombic potentials. Applications of this routine demonstrate the goodness of the high scoring, geometrically docked conformations of the bound crystal complexes.

Four-helix bundles are identified and characterized in the subunit interfaces of protein multimers. We find that this motif occurs as often in the interfaces as in the protein monomers. Common and different characteristics demonstrated by the bundles in the two environments suggest the possible stabilization mechanisms of the bundlesviacooperative helical twist, dipole alignment and interhelical connections. Nucleation of parallel helix pairs may be a favourable pathway before the pairs couple into bundles during folding. Certain properties found chaotic in the interface four-helix bundles indicate that either the subunit association is far from the global minimum conformation, or that the footprints of the folding pathway are recorded in these properties.