落地抱杆提升方式安全性分析的探讨

本文结合输变电工程所用抱杆组立方式要求,对□700、□750及□800三种规格抱杆的提升方式进行了分析,明确了下支座、回转支承、上支座及回转节等参数,对比分析了摇臂端部结构、摇臂中部结构等,并对抱杆的中心位置与铁塔中心位置的偏移值进行了量化对比分析。研究表明,在施工过程中应控制抱杆的中心位置与铁塔中心位置不发生偏移,□750落地抱杆的参数效果最佳。

CAUSALITY DIAGRAM BASED SAFETY ANALYSIS OF MICRO TURBOJET ENGINE

An improved safety analysis based on the causality diagram for the complex system of micro aero-engines is presented.The study is examined by using the causality diagram in analytical failure cases due to rupture or pentration in the receiver of micro turbojet engine casing,and the comparisons are also made with the results from the traditional fault tree analysis.Experimental results show two main advantages：（1）Quantitative analysis which is more reliable for the failure analysis in jet engines can be produced by the causality diagram analysis;（2）Graphical representation of causality diagram is easier to apply in real test cases and more effective for the safety assessment.

Security Model for Analyzing Data Privacy in Multipath Transport

In order to investigate the enhancement of data privacy by distributing data packets via multiple paths, this paper fommlates a security model and analyzes the privacy problem in mul- tipath scenarios leveraging inforrmtion theoretic concept. Based on proposed model, a privacy function related to the path number is discussed. We heuristically recommend the optin^al path num- ber and analyze the tradeoff among the perform- ance, resource consumption and privacy. For re- ducing the inforlmtion leakage, the data schedule algorithms are also proposed. The analytical model can provide guidelines for the multipath protocol design.

Security analysis of access control model in hybrid cloud based on security entropy

To resolve the problem of quantitative analysis in hybrid cloud,a quantitative analysis method,which is based on the security entropy,is proposed.Firstly,according to the information theory,the security entropy is put forward to calculate the uncertainty of the system' s determinations on the irregular access behaviors.Secondly,based on the security entropy,security theorems of hybrid cloud are defined.Finally,typical access control models are analyzed by the method,the method's practicability is validated,and security and applicability of these models are compared.Simulation results prove that the proposed method is suitable for the security quantitative analysis of the access control model and evaluation to access control capability in hybrid cloud.

Laparoscopic distal pancreatectomy is as safe and feasible as open procedure:A meta-analysis

AIM:To evaluate the feasibility and safety of laparoscopic distal pancreatectomy(LDP) compared with open distal pancreatectomy(ODP).METHODS:Meta-analysis was performed using the databases,including PubMed,the Cochrane Central Register of Controlled Trials,Web of Science and BIOSIS Previews.Articles should contain quantitative data of the comparison of LDP and ODP.Each article was reviewed by two authors.Indices of operative time,spleen-preserving rate,time to fluid intake,ratio of malignant tumors,postoperative hospital stay,incidence rate of pancreatic fistula and overall morbidity rate were analyzed.RESULTS:Nine articles with 1341 patients who underwent pancreatectomy met the inclusion criteria.LDP was performed in 501(37.4%) patients,while ODP was performed in 840(62.6%) patients.There were significant differences in the operative time,time to fluid intake,postoperative hospital stay and spleen-preserving rate between LDP and ODP.There was no difference between the two groups in pancreatic fistula rate [random effects model,risk ratio(RR) 0.996(0.663,1.494),P = 0.983,I2 = 28.4%] and overall morbidity rate [random effects model,RR 0.81(0.596,1.101),P = 0.178,I2 = 55.6%].CONCLUSION:LDP has the advantages of shorter hospital stay and operative time,more rapid recovery and higher spleen-preserving rate as compared with ODP.

Toward an RSU-unavailable Lightweight Certificateless Key Agreement Scheme for VANETs

Vehicle ad-hoc networks have developed rapidly these years,whose security and privacy issues are always concerned widely.In spite of a remarkable research on their security solutions,but in which there still lacks considerations on how to secure vehicleto-vehicle communications,particularly when infrastructure is unavailable.In this paper,we propose a lightweight certificateless and oneround key agreement scheme without pairing,and further prove the security of the proposed scheme in the random oracle model.The proposed scheme is expected to not only resist known attacks with less computation cost,but also as an efficient way to relieve the workload of vehicle-to-vehicle authentication,especially in no available infrastructure circumstance.A comprehensive evaluation,including security analysis,efficiency analysis and simulation evaluation,is presented to confirm the security and feasibility of the proposed scheme.

Analysis on Key Technology of ＂Cloud Computing＂

This paper introduces the background of cloud computing, takes analysis of key technology, analysis of cloud computing and traditional competitive intelligence information model for comparative study, for the security of cloud computing, function and service of the following aspects to elaborate, to explore the influence of cloud computing on the information.

Analysis on the Security Enhancement Model of Communication System based on Chaotic Encryption and Analytic Hierarchy Process

In this paper, we conduct research on the security enhancement model of communication system based on the chaotic encryption and analytic hierarchy process. The communication of the information network is completed by the communication protocol. The communication protocol can be divided into application layer, transport layer, network layer, link layer and physical layer. By using the communication protocol, the security control of the network communication can meet the needs of the information network security communication. This paper integrates the chaos system to further implement the robust system architecture. The algorithm of this paper tries to make the maximum value of the above three parameters in each iteration step by step and the output feedback to dynamically change these parameters. Compared with other algorithms, our method can adopt more related theories to perform the better result.

Evaluating the Ecological Security of Land Resources based on Multi-source Data in the Altay Region of China

As a material carrier contributing to human survival and social sustainable development,the ecological environment is declining in its integrity and overall health.With the rapid development of society and economy,it is currently very necessary to carry out ecological security evaluation research to provide scientific guidance and suggestions for the construction of ecological civilization and the harmonious co-existence between man and nature.Taking Altay region as the research area,this paper collected and integrated regional geological,geographical,cultural,socio-economic,and statistical data,as well as previous research results.Combined with DPSIR and EES framework model,the evaluation index system of land resource ecological security in Altay region was constructed by using the analytic hierarchy process,entropy method and linear weighted summation function method.Using this index system,the evaluation research work was carried out to determine the current state of the security situation and the major threats which should be addressed.(1)The overall ecological security situation of Altay region was relatively safe,while the local ecological security situation was relatively fragile.Among them,the areas with safe and safer ecological environment accounted for 38.72%,while the areas with critically safe status accounted for 30.83%,and the areas with a less safe and unsafe environment accounted for 30.45%.In terms of spatial characteristics,the areas with unsafe ecological environment were mainly distributed in the west and east of the study area,while the areas with good ecological environment were distributed in the north of the study area.(2)Large-scale mining activities,frequent geological disasters,large-scale reclamation and long-term cultivation of arable land,and long-term large-scale grazing activities resulting in the destruction of grassland and vegetation were the main factors leading to the prominent ecological security problems of land resources in the Altay region.Therefore,in the process of the continuous development of the urban economy,we should pay more attention to the harmony between man and nature,and also actively and effectively advocate and implement certain policies and measures,such as returning farmland to forest,returning grazing land to grassland and integrating the mining of mineral resources.

Spatial Linear Combination Forecasting Model and Its Application

The accuracy of spatial forecasting is close relation to the selection of spatial forecasting model. Each model from special aspects using special spatial data has its own advantage or disadvantage. A more accurate spatial forecasting model can be obtained by a linear combination of some models. In this study, first-order spatial autoregressive （SAR（1）） model, Kriging algorithm interpolation （KAI） model and back-propagation neural network （BPNN） model are established by using cross-section data or time series data. A spatial linear combination forecasting （SLCF） model is obtained by the combination models mentioned above. An empirical research by these models is carried out with forecasting some areas＇ GDP per capita in Fujian, 2003. It is found that the best one is the SLCF model.