Current status and prospects of research on safety situation awareness of high speed railway operation environment

Purpose–The safety of high-speed rail operation environments is an important guarantee for the safe operation of high-speed rail.The operating environment of the high-speed rail is complex,and the main factors affecting the safety of high-speed rail operating environment include meteorological disasters,perimeter intrusion and external environmental hazards.The purpose of the paper is to elaborate on the current research status and team research progress on the perception of safety situation in high-speed rail operation environment and to propose directions for further research in the future.Design/methodology/approach–In terms of the mechanism and spatio-temporal evolution law of the main influencing factors on the safety of high-speed rail operation environments,the research status is elaborated,and the latest research progress and achievements of the team are introduced.This paper elaborates on the research status and introduces the latest research progress and achievements of the team in terms of meteorological,perimeter and external environmental situation perception methods for high-speed rail operation.Findings–Based on the technical route of“situational awareness evaluation warning active control,”a technical system for monitoring the safety of high-speed train operation environments has been formed.Relevant theoretical and technical research and application have been carried out around the impact of meteorological disasters,perimeter intrusion and the external environment on high-speed rail safety.These works strongly support the improvement of China’s railway environmental safety guarantee technology.Originality/value–With the operation of CR450 high-speed trains with a speed of 400 kmper hour and the application of high-speed train autonomous driving technology in the future,new and higher requirements have been put forward for the safety of high-speed rail operation environments.The following five aspects of work are urgently needed:(1)Research the single factor disaster mechanism of wind,rain,snow,lightning,etc.for high-speed railways with a speed of 400 kms per hour,and based on this,study the evolution characteristics of multiple safety factors and the correlation between the high-speed driving safety environment,revealing the coupling disastermechanism ofmultiple influencing factors;(2)Research covers multi-source data fusion methods and associated features such as disaster monitoring data,meteorological information,route characteristics and terrain and landforms,studying the spatio-temporal evolution laws of meteorological disasters,perimeter intrusions and external environmental hazards;(3)In terms of meteorological disaster situation awareness,research high-precision prediction methods for meteorological information time series along high-speed rail lines and study the realization of small-scale real-time dynamic and accurate prediction of meteorological disasters along high-speed rail lines;(4)In terms of perimeter intrusion,research amulti-modal fusion perception method for typical scenarios of high-speed rail operation in all time,all weather and all coverage and combine artificial intelligence technology to achieve comprehensive and accurate perception of perimeter security risks along the high-speed rail line and(5)In terms of external environment,based on the existing general network framework for change detection,we will carry out research on change detection and algorithms in the surrounding environment of highspeed rail.

The Management of Environment Cost Caused by Ballast Water

According to classical economic theory,external cost is the indirect,and uncompensated,social or environmental cost caused to an uninvolved third party that arises as an effect of another party’s activity.In light of this,the environmental cost caused by ballast water is considered as a negative externality.This paper aims to contribute by proposing that the environmental cost caused by ballast water can be determined through questionnaires,and that the imposition of a Pigouvian retributive tax is required to compensate for the environmental damage caused.The paper proceeds as follows.Firstly,ballast water management is discussed.Second,the environmental cost is discussed and it is asserted that it is important to have clear regulations and to update them frequently to prevent or minimize ballast water’s negative impact on the environment.Finally,it is suggested that the environmental cost caused by ballast water can be determined by questionnaires and,more specifically,by the WTP(Willingness to Pay)method,and that a special Pigouvian corrective taxation which can internalize this cost should be imposed.

Strengthened Monitoring of H5 Avian Influenza Viruses in External Environment in Hubei, 2018

The contamination status of H5 avian influenza viruses and distribution of subtypes of H5N1 and H5N6 in poultry-related environment of Hubei areas were investigated.Urban and rural live poultry markets,poultry farms,intensive livestock farms and other monitoring types of 103 counties in 17 cities were selected in Hubei.Wiping samples from cage surface,wiping samples from chopping board,fecal specimens and other environmental samples were collected and tested by real-time RT-PCR using primers and probes of influenza A,avian influenza of H5,N1 and N6 from December 2017 to March 2018.The avian influenza virus positive rate was compared among different monitoring sites,samples,time and regions.Totally,7132 environmental samples were collected in 1634 monitoring points with a positive rate of 2.24%.The positive rate of H5 avian influenza virus was the highest in urban and rural live poultry markets(3.44%,x^2=61.329,P<0.05)in 6 monitoring sites and wiping samples from chopping board(5.46%,x^2=67.072,P<0.05)in 6 sample types.H5N6 avian influenza viruses were detected more in eastern than western Hubei,and H5N6 avian influenza viruses were detected only in Xiangyang city of western Hubei.There were important high-risk places of human infection with H5 avian influenza virus in urban and rural live poultry markets and the poultry slaughtering plants.H5N6 has been the predominant subtype of H5 avian influenza viruses in the eastern and western Hubei and H5N6 avian influenza viruses were still present in a few areas of Hubei.Outbreaks of human H5N1 and H5N6 avian influenza remain at risk in Hubei province.

TOWARDS SPATIAL LINKAGE PATTERNS OF INDUSTRIAL ORGANIZATIONS IN CHINA

The paper attempts to examine the relationships botween industrial organizations and their environments from an essentially spatial perspective and organizational theory, and inteqrate the generalizations derived from organizational theory and industrial geography o identify spatial linkage pattems created by the enterprises, both in the aggregate and individually These issues are organized around three elements. From the many organizational and environmental factors which might influence the spatial linkage patterns, six have been selected for analysis. These factors were highly correlated with value or volume of spatial linkages. Changes of spatial linkage pattems over time were analyzed based on a representative sample of the Nanjing Automotive Industrial Corporation, and findings with case studies were illustrated.

Hallmark of a Resilient City: Adoption of Green Infrastructure in African Cities

Dynamic urbanization of African cities has created development trajectories that face systemic challenges in the provision of sustainable and ecologically resilient urban environments. The specific challenges include extensive unregulated growth with informal settlements reflecting poor service levels and high poverty indices, inadequacy in provision of basic services in health, water, housing, transport and communication infrastructure, high reliance on biomass fuels, exposure to environmental stress and implausible climate change coping and mitigation mechanisms among others. Review of extensive literature and synthesis of existing bodies of knowledge on the ecological and management perspectives of urban environments revealed many gaps and understanding of urban transformation processes. The purpose of this review was to contextualize credible pathways for optimization of both ecosystem goods and services from green urban landscapes (Green infrastructure) and non-green infrastructure to ensure sustainable and ecologically resilient urban environments. Attempts were made to rationalize and validate through discussions the benefits of managed urban ecosystems for African cities. On the basis of the evidence from the literature, it is concluded that urban development trajectories that do not embrace multifaceted approaches that deliberately retain and maintain green infrastructure in the urban environment may not be cost-effective. It is recommended that systematic integration of urban forestry concepts in urban planning that involves communities, local and national governments, business entrepreneurs and public and private research institutions provides tenable frameworks for addressing current and future challenges of urbanization in Africa.

DYNAMIC MODEL OF CROP GROWTH SYSTEM AND NUMERICAL SIMULATION OF CROP GROWTH PROCESS UNDER THE MULTI-ENVIRONMENT EXTERNAL FORCE ACTION

According to the biomechanic theory and method, the dynamic mechanism of crop growth under the external force action of multi_environment factors (light, temperature,soil and nutrients etc.) was comprehensively explored.Continuous_time Markov(CTM) approach was adopted to build the dynamic model of the crop growth system and the simulated numerical method. The growth rate responses to the variation of the external force and the change of biomass saturation value were studied. The crop grew in the semiarid area was taken as an example to carry out the numerical simulation analysis, therefore the results provide the quantity basis for the field management. Comparing the dynamic model with the other plant growth model, the superiority of the former is that it displays multi_dimension of resource utilization by means of combining macroscopic with microcosmic and reveals the process of resource transition. The simulation method of crop growth system is advanced and manipulated. A real simulation result is well identical with field observational results.

Perspective of World Economy and China's External Economic Environment

Owing to a series of impacts of the "9·11 terrorist attack," the accounting scandals of big companies, Iraq War and the SARS crisis in the past two years, the world economy that might have rebounded forcefully has been on a wavering process of slow recovery.

China's External Economic Environment in the Early New Century

Four Changes in World EconomyFirst,a new round of global economic growth is under way.In 2000,oil pricerose rapidly,stoek markets and exchange rates remained volatile and interestrates went up.All these disadvantages did not undermine the foundations of worldeconomy,and the average growth rate of global gross domestic product(GDP)

Mid-short-term risk assessment of power systems considering impact of external environment

Ice flashover,lightning flashover and bird damage are the main reasons that cause transmission facility failure.The impact of these environmental factors on the operational risk levels of power systems should be taken into account in power system maintenance scheduling and operation planning.This paper studies the midshort-term risk assessment methodology considering the impact of the external environment.The relationship model between natural disasters and transmission lines is presented.The conditional outage rate model and the sampling technique are then proposed considering the correlated outage of multiple transmission lines when a disaster happens.The framework of the mid-short-term risk assessment model is outlined.A test case of Jiangxi provincial power grid validates the proposed model.The results show that the model can quantify the impact of disasters on the forced outage rate of transmission component and their outage correlation,and thus effectively revealing the mid-short-term risk of power systems.The model can facilitate a more strategic decision-making on maintenance scheduling and operation planning of power systems.

城市绿地如何吸引老年人--外部环境特征与使用频率的关系初探

A high-grade green space environment will provide necessary environmental support to the outdoor activities of disadvantaged groups including the elderly and is thus helpful for promoting their physical activity level and life quality.This paper takes the urban area of Dalian City as an example and divides the external environmental characteristics of a green space into three aspects including the diversity degree of facilities,the richness level of street functions,and the mixing degree of land use.Based on the data of a survey on activities by elderly in green space,the paper conducts an in-depth study on the statistical correlation between the external environmental characteristics of green space and the frequency of use by the elderly.The study shows that diversified facility types around a green space are conducive to a rise in the frequency of use of this space by the elderly,out of which the effect of functional facilities such as school and food market is the most significant.In addition,being adjacent to streets full of daily life or being mixed with residential land use will increase the frequency of use of the green space by the elderly.This paper puts forward certain environmental upgrading strategies for green space from the perspective of external environmental characteristics in order to help build up green space that is use-friendly to the elderly.