Search

Aiming at the problem of how to select high risk key defense area under the condition of limited urban defense force, to maximize the utility of limited force and minimize the urban risk, this paper proposes a method of selecting key defense area based on regional comprehensive risk assessment. Firstly, a reasonable risk assessment index system is constructed from the perspective of the intruder and the defender. Secondly, based on the idea of equivalent energy, the weight product normalization method is proposed to determine the combined weight of the target risk index, and then calculate the target risk value. Then, according to the centroid theory, the weighted centroid calculation model of target distribution is constructed, and the dispersion matrix is established to calculate the dispersion of regional target distribution. Finally, the regional comprehensive risk assessment function is constructed according to the area of risk radar map, and the comprehensive risk of each region is quantitatively assessed according to the target situation of districts I to VI of a city. The results show that compared with the target risk coupling method, the proposed method can realize the regional comprehensive risk assessment more accurately, and provide decision-making basis for the selection of key urban defense areas and the efficient deployment of limited forces.

Aiming at the problem of uncertainty and complexity of battlefield situation, which leads to the poor accuracy of risk prediction in the process of research and judgment, it is proposed to build a situation-risk model and construct the risk possibility distribution in order to realize the accurate prediction of risk. Firstly, the risk prediction index system is established from the enemy situation, our situation and the battlefield environment situation research and judgment content; secondly, the role of situation information on the risk is analyzed, and the risk model such as exponential, Z-type, tangent and so on is constructed and the risk value interval is calculated; then, based on the fuzzy function constructing method in the possibility theory, and relying on the weighting difference and uncertainty measurement, the risk possibility distribution is constructed within the risk value interval. Finally, an example of a defense mission is used to verify the feasibility and reasonableness of the proposed method by combining the expert system and cloud modeling methods in an experiment. The results show that the proposed method can fully take into account the uncertainty of situational information in risk prediction, which provides an important basis for subsequent planning decision-making.

In this study, we divide the region covering Shandong Province into inland and peninsula area. By using the surface meteorological observation and sounding data from the MICAPS, we have conducted a classification to the thunderstorm gale events occurred between April and September from 2009 to 2016 in Shandong Province primarily based on the 500 hPa synoptic systems. In addition, based on the mesoscale weather systems in the 850 hPa and at the surface, the different patterns of thunderstorm gale events are classified. Then the physical diagnose of each pattern of thunderstorm gale event is statistically analyzed by using the percentile method, and the critical values of these physical diagnoses are given. The results show that (1) based on the configuration of the 500 hPa weather influence systems, the thunderstorm gales in Shandong can be divided into pre-trough pattern, post-trough pattern and around subtropical high pattern. Additionally, according to the relation between the falling area of thunderstorm strong wind and the 850 hPa weather systems, they can also be divided into three types, i.e. shear line convergence, southerly airflow convergence and northerly airflow convergence. Furthermore, according to the position relationship between the weather system and the thunderstorm gale in the sea-level pressure field, the surface weather systems that generate thunderstorms high winds can be mainly divided six types. (2) The suitable physical diagnoses of thunderstorm gales between April and June in the inland area of Shandong are temperature difference (ΔT850-500) between 850 hPa and 500 hPa, velocity difference (ΔV500-850) between 500 hPa and 850 hPa, Storm Strength Index (SSI) and Wind Index (WI), while in the peninsula area of Shandong, the physical diagnoses SSI and WI, which can represent the comprehensive characteristics of atmospheric thermodynamics and dynamics, show a good indication to thunderstorm gales in this area. (3) The physical diagnoses Convective Available Potential Energy (CAPE), K index, Lift Index (LI), pseudo-equivalent potential temperature difference (Δθse700-850) between 700 hPa and 850 hPa and severe weather threat index (SWEAT), representing atmospheric thermal instability, have good indicative signification to the thunderstorm gales between July and August in Shandong province. (4) Δθse700-850, SSI, SWEAT and ΔV500-850 have good indication to the thunderstorm gales occurred in the peninsula area of Shandong in September.

For understanding the abnormal water level of Delingha Gahai well in Qinghai Province in 2018, the relevant information about the well is reviewed. The two water level instruments of the well are stable and consistent in operation. The anomalies in this period are not related to rainfall and air pressure, and the apparent stress value in vicinity of the well hole is high, which indicates that the crustal stress level in this area is further enhanced. The correlation analysis on amplitude variance of water level and first-order difference shows that the abnormal reliability is high, which reflects the regional tectonic activity information. This is a common precursor of two moderate earthquakes in its surrounding area, and belong to short-term and medium-term anomalies.