Discussion on Integrated Modeling Technology of New Generation Centralized Control Station Equipment Monitoring System

At present, the substation SCD model mainly aims at the modeling of primary equipment and secondary equipment, and the description of auxiliary equipment and substation area model is missing. According to the characteristics of equipment monitoring of the new generation centralized control station, the description of auxiliary equipment model and area model needs to be added to the original IEC61850 standard. In the first mock exam station, the current business requirements of centralized control station are analyzed. A unified model structure of master station is designed. Based on the definition of IEC61850 standard, a method and example of extending auxiliary device model and regional model are given. The proposed auxiliary equipment and area modeling method based on IEC61850 standard can make up for the shortcomings of the original standard, support the equipment monitoring of the new generation centralized control station and realize rich application functions.

Micro-asperity Contact Area considering Strain Hardening for Metallic Materials

A novel micro-asperity contact area model, which considers influences of strain hardening, is proposed to describe contact area between a deformable sphere and a rigid flat for metallic materials. Firstly a generalized formula considering work-hardening behaviors (Pilling-up or Sinking-in) between contact area and interference is proposed for fully plastic regime based on the definition of plastic contact area index. Then a relationship to calculate the critical interference at the inception of fully plastic deformation is derived. In order to incorporate the transition from elastic regime to fully plastic regime, a quadratic rational form formula is proposed based volume conservation model for mixed elastoplastic regime. Therewith a modification is conducted to ensure continuity of contact area model at critical interference for fully plastic regime. Ultimately several representative models and experiment results are exhibited to analyze the availability of present model. It is noted considering work-hardening fully plastic contact area index is not a constant value of 2 for any metallic materials, which is a function of strain hardening exponent. Demonstration testifies that smoothness constraint is not necessary at the critical interferences. The prediction data of present model is consistent with experiment results contrasting that of other models. Current generalized contact area model considering influence of work-hardening results in a better understanding of the contact area between a deformable sphere and a rigid flat and indicates a probability to analyze contact characteristics of two mating rough surfaces accurately.

Measuring COVID-19 vaccination coverage: an enhanced age-adjusted two-step floating catchment area model

Background There are only limited studies on access to COVID-19 vaccines and identifying the most appropriate health centres for performing vaccination in metropolitan areas. This study aimed to measure potential spatial access to COVID-19 vaccination centres in Mashhad, the second-most populous city in Iran. Methods The 2021 age structure of the urban census tracts was integrated into the enhanced two-step floating catchment area model to improve accuracy. The model was developed based on three different access scenarios: only public hospitals, only public healthcare centres and both (either hospitals or healthcare centres) as potential vaccination facilities. The weighted decision-matrix and analytic hierarchy process, based on four criteria (i.e. service area, accessibility index, capacity of vaccination centres and distance to main roads), were used to choose potential vaccination centres looking for the highest suitability for residents. Global Moran’s index (GMI) was used to measure the spatial autocorrelation of the accessibility index in different scenarios and the proposed model. Results There were 26 public hospitals and 271 public healthcare centres in the study area. Although the exclusive use of public healthcare centres for vaccination can provide the highest accessibility in the eastern and north-eastern parts of the study area, our findings indicate that including both public hospitals and public healthcare centres provide high accessibility to vaccination in central urban part. Therefore, a combination of public hospitals and public healthcare centres is recommended for efficient vaccination coverage. The value of GMI for the proposed model (accessibility to selected vaccination centres) was calculated as 0.53 (Z = 162.42, P < 0.01). Both GMI and Z-score values decreased in the proposed model, suggesting an enhancement in accessibility to COVID-19 vaccination services. Conclusions The periphery and poor areas of the city had the least access to COVID-19 vaccination centres. Measuring spatial access to COVID-19 vaccination centres can provide valuable insights for urban public health decision-makers. Our model, coupled with geographical information systems, provides more efficient vaccination coverage by identifying the most suitable healthcare centres, which is of special importance when only few centres are available. Graphic abstract

Geospatial Analysis and Research on Social and Spatial Inequality of Compulsory Education: A Case Study of Hangzhou, China

Equal compulsory education is an important way to realize social and spatial equality, while the uneven allocation of educational resources in different regions and groups results in inequality of opportunity and solidification of social strata. Traditional research conducted on the basis of fixed search range ignores the special institutional background of Chinese school district system. In this paper, an improved Gaussian two-step floating catchment area model is developed taking into consideration the school district system, while the bivariate local spatial analysis method and geographically weighted regression model are employed to study the social and spatial differentiation of compulsory education accessibility and its capitalization effects in Hangzhou. Results show that (1) the improved Gaussian two-step floating catchment area model is more in line with the national condition of China’s “nearby schooling” policy; (2) the accessibility of compulsory schools in Hangzhou shows an obvious core-periphery typology, and the aggregation effect of primary school accessibility is more significant than that of secondary schools; (3) compared to groups with high socioeconomic status, vulnerable groups are highly disadvantaged in terms of access to educational services; (4) spatial heterogeneity exists in education capitalization, and the areas where education accessibility has the strongest impact on housing prices are in the central city with rich high-quality educational resources; (5) high-quality educational resources, high-priced communities, clusters of high socioeconomic status groups, and communities enjoying high-level education accessibility are highly consistent in all spaces, which is the spatial expression of educational inequality. The research on Hangzhou, a regional central city, provides a theoretical basis and technical support for the humanistic shift in the allocation of educational resources.