City In Southern China Research Articles

Detection of short-term urban land use changes by combining SAR time series images and spectral angle mapping

Rapid urban sprawl and re-construction of old towns have been leading to great changes of land use in cities of China. To witness short-term urban land use changes, rapid or real time remote sensing images and effective detection methods are required. With the availability of short repeat cycle, relatively high spatial resolution, and weather-independent Synthetic Aperture Radar (SAR) remotely sensed data, detection of short-term urban land use changes becomes possible. This paper adopts newly released Sentinel-1 SAR data for urban change detection in Tianhe District of Guangzhou City in Southern China, where dramatic urban redevelopment practices have been taking place in past years. An integrative method that combines the SAR time series data and a spectral angle mapping (SAM) was developed and applied to detect the short-term land use changes. Linear trend transformations of the SAR time series data were first conducted to reveal patterns of substantial changes. Spectral mixture analysis was then conducted to extract temporal endmembers to reflect the land development patterns based on the SAR backscattering intensities over time. Moreover, SAM was applied to extract the information of significant increase and decrease patterns. The results of validation and method comparison showed a significant capability of both the proposed method and the SAR time series images for detecting the short-term urban land use changes. The method received an overall accuracy of 78%, being more accurate than that using a bi-temporal image change detection method. The results revealed land use conversions due to the removal of old buildings and their replacement by new construction. This implies that SAR time series data reflects the spatiotemporal evolution of urban constructed areas within a short time period and this study provided the potential for detecting changes that requires continuously short-term capability, and could be potential in other landscapes.

Effects of urban form on air quality in China: An analysis based on the spatial autoregressive model

Understanding how urban air quality depends on urban form can have important implications for improving urban air quality by optimizing urban planning and management policies. This study employed the spatial autoregressive model to explore the effect of urban form on urban air quality in 288 prefecture-level cities in China. Information on the air quality (AQI) and six criteria pollutants (PM2.5, PM10, CO, SO2, NO2, O3) were obtained from the hourly observation data of 1333 in-situ air monitoring stations throughout 2015. Urban form is characterized by five metrics, including urban size, shape, sprawl, fragmentation and traffic accessibility, and it is calculated based on land cover data. Results show that urban shape complexity and population density have a significant negative impact on urban air quality. Large city size is strongly related to comparatively poor air quality for cities in Southern China and only shows a slight association with emissions in Northern China. In general, lower-sized, scattered, polycentric cities provide better air quality in China. It is suggested that higher air quality and fewer pollutant emissions can be achieved through urban form planning and management policies, which aim to restrict the blind expansion of urban land and encourage moderately scattered, polycentric urban development.

Diagnosis of sewer pipe defects on image recognition of multi-features and support vector machine in a southern Chinese city

Closed circuit television (CCTV) systems are widely used to inspect sewer pipe conditions. During the diagnosis process, the manual diagnosis of defects is time consuming, labor intensive and error prone. To assist inspectors in diagnosing sewer pipe defects on CCTV inspection images, this paper presents an image recognition algorithm that applies features extraction and machine learning approaches. An algorithm of image recognition techniques, including Hu invariant moment, texture features, lateral Fourier transform and Daubechies (DBn) wavelet transform, was used to describe the features of defects, and support vector machines were used to classify sewer pipe defects. According to the inspection results, seven defects were defined; the diagnostic system was applied to a sewer pipe system in a southern city of China, and 28,760 m of sewer pipes were inspected. The results revealed that the classification accuracies of the different defects ranged from 51.6% to 99.3%. The overall accuracy reached 84.1%. The diagnosing accuracy depended on the number of the training samples, and four fitting curves were applied to fit the data. According to this paper, the logarithmic fitting curve presents the highest coefficient of determination of 0.882, and more than 200 images need to be used for training samples to guarantee the accuracy higher than 85%.

Effect of meteorological factors on scarlet fever incidence in Guangzhou City, Southern China, 2006–2017

ObjectiveTo explore the relationship between meteorological factors and scarlet fever incidence from 2006 to 2017 in Guangzhou, the largest subtropical city of Southern China, and assist public health prevention and control measures. MethodsData for weekly scarlet fever incidence and meteorological variables from 2006 to 2017 in Guangzhou were collected from the National Notifiable Disease Report System (NNDRS) and the Guangzhou Meteorological Bureau (GZMB). Distributed lag nonlinear models (DLNMs) were conducted to estimate the effect of meteorological factors on weekly scarlet fever incidence in Guangzhou. ResultsWe observed nonlinear effects of temperature, relative humidity, and wind velocity. The risk was the highest when the weekly mean temperature was 31 °C during lag week 14, yielding a relative risk (RR) of 1.48 (95% CI: 1.01–2.17). When relative humidity was 43.5% during lag week 0, the RR was 1.49 (95% CI: 1.04–2.12); the highest RR (1.55, 95% CI: 1.20–1.99) was reached when relative humidity was 93.5% during lag week 20. When wind velocity was 4.4 m/s during lag week 13, the RR was highest at 3.41 (95% CI: 1.57–7.44). Positive correlations were observed among weekly temperature ranges and atmospheric pressure with scarlet fever incidence, while a negative correlation was detected with aggregate rainfall. The cumulative extreme effect of meteorological variables on scarlet fever incidence was statistically significant, except for the high effect of wind velocity. ConclusionWeekly mean temperature, relative humidity, and wind velocity had double-trough effects on scarlet fever incidence; high weekly temperature range, high atmospheric pressure, and low aggregate rainfall were risk factors for scarlet fever morbidity. Our findings provided preliminary, but fundamental, information that may be useful for a better understanding of epidemic trends of scarlet fever and for developing an early warning system. Laboratory surveillance for scarlet fever should be strengthened in the future.

Traffic control approach based on multi‐source data fusion

A multi-source data-driven traffic control approach is developed to alleviate traffic overload at bottleneck road segments. In the proposed approach, the high-penetration feature of mobile-phone signalling data and the real-time feature of taxi global-positioning-system data are combined to simulate traffic flows in the road network of Shenzhen, a major city of southern China. The road intersections for implementing traffic control schemes are selected by locating the major vehicle sources of the bottleneck road segments, and a genetic algorithm was used to solve the dynamic traffic control schemes. Two important bottleneck road segments in Shenzhen were used as case studies to test the effectiveness of the proposed approach. The authors also propose a method to calibrate the simulated traffic flows when traffic count data are available in the future.

The Research on the Outpatient Cost Adjustment Framework of the Urban Workers in a Southern China City During 2013 to 2015.

Based on a large amount of data, the study aimed to analyze all expenses of outpatients in a southern China city from 2013 to 2015. It draws a conclusion that the total cost of outpatient has increased in the past 3 years, and various cost indexes either increased or decreased in different ways. Drug costs and treatment fees are the main influencing factors for the change in total outpatient cost. The structural change from 2013 to 2015 was 70.15%. Drug costs, laboratory fees, and inspection fees are the main indexes that account for the increasing total outpatient costs. This study puts emphasis on the cost of human resources, which eliminates the phenomenon of “Yi Yao Yang Yi” (support medical cost with medicine) and “Yi Xie Yang Yi” (support medical cost with medical device). This study also focuses on the balance of outpatient cost, as well as the compensation function of medical insurance, which encourages multiple participation and coordinated adjustment.

Hong Kong in 2018: Relative Calm and Getting Down to Work

Hong Kong has been relatively calm under the watch of Chief Executive Carrie Lam. Connectivity in terms infrastructure between Hong Kong and China has been strengthened with a US$10 billion railway linking the most dynamic cities in southern China. Media freedom continues to be a flashpoint between foreign journalists and Beijing but in local elections, pro-government candidates like Chan Hoi-yan easily defeated experienced pan-democracy candidates in the Kowloon West by-election.

Progresses on the intelligent construction and operation maintenance of urban under-lake tunnels

China is currently at an important stage of urbanization. In recent years, the number and scale of under-lake tunnels in southern cities of China are growing consistently, which brings opportunities and challenges in intelligent construction and operation maintenance. Due to the long length of the under-lake tunnel, the large volume of concrete to be cast, the complex environment of the buried section and the underground environment of the lake bottom, the hydration heat and stress crack have been the main challenges of the under-lake tunnel engineering in crack control and waterproofing aspect. Simultaneously, with the development of big data, intelligent construction, information technology, and other techniques, these techniques are gradually applied to the whole life cycle of tunnel engineering including survey, design, construction, operation, and maintenance. The construction of the lake tunnel project is setting off a new round of technological innovation. This paper systematically summarizes the technical breakthroughs and application of technologies such as intelligent construction and information technology in the construction of under-lake tunnels in China, and puts forward reasonable suggestions on the key technologies of intelligent construction and operation maintenance for urban under-lake tunnel engineering.

Quitting Smoking in Mainland China: A New Role for Hospital-Based Nurses.

China has more than 300 million cigarette smokers and 1 million deaths every year attributed to smoking. Despite its huge economic implications, the lack of smoking and associated lifestyle-related data on China's outpatients makes it difficult for health care professionals to provide individualized assessments and targeted interventions. This study aimed to identify factors to inform nurse-led smoking behavioral assessments and cessation interventions. Clinical data from new patients attending the family medicine outpatient department from a large tertiary hospital in a major Southern China city were collected between March and December 2015. Data including basic demographics, medical history, vaccination history, current medication, and information on lifestyle risk factors were collected by frontline nurses during nursing assessment on their initial visit. Chi-square and Student's t tests were used as univariate analysis and post hoc regression analysis to explore which factors contributed toward smoking cessation. Of 7913 eligible visits, smokers and ex-smokers accounted for 13.5% and 2.4% of new patients, respectively, with a majority of them being young and male (gender ratio of 8:1) smokers. Multiple behavioral risks and comorbidities such as hypertension and diabetes mellitus in smokers were common; for example, 17.9% of smokers were also current drinkers, making alcohol users 8.5 to 16.7 times more likely to have smoked. Ex-smokers were more likely to be divorced, to be ex-drinkers, or to have higher diastolic blood pressure and concurrent hypertension. Smoking and associated lifestyle risk assessments run by registered nurses should be incorporated into current outpatient health histories and in targeted smoking cessation intervention programs.

How Medic–Patient Communication and Relationship Influence Chinese Patients’ Treatment Adherence

The deterioration of medic–patient relation in China raises the question about its impact on patients’ adherence to medical instructions. This study focuses on how the quantity and quality of medic–patient communication influences their relationship, and how the perceived relationship at individual level, institution level, and society level influences patients’ treatment adherence, through a survey conducted in a city of Southern China (N = 597, Response rate = 66%). The results of path analysis show that consulting time is positively associated with patients’ relationship with individual doctors and the whole medical system, as well as their satisfaction with hospital. Unpleasant experience of having disputes with medical workers is negatively associated with the medic–patient relationship at all of the three levels and causes conditional nonadherence. The more positive medic–patient relationship perceived by the patients, the more likely they will display unconditional adherence.

The synergetic control of NO2 and O3 concentrations in a manufacturing city of southern China

This study explored effective methods to control NO2 and O3 concentrations in a manufacturing city, Foshan, in the Pearl River Delta (PRD) region. A “double high” pollution episode (i.e., both NO2 and O3 concentrations exceeding the ambient air quality standards of China) was selected as a typical case to identify a collaborative control method for NO2 and O3 by using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) and the Empirical Kinetic Modeling Approach (EKMA). Considering the nonlinear relationship between O3 and its precursors; we scaled down the volatile organic carbons (VOC) and NOx emission inventories to investigate O3 responses. The results showed that Foshan is VOC-sensitive and that the VOC-NOx reduction ratio more than 1:1 not only helped to steadily reduce O3 concentrations but also to avoid an increase in NO2 concentrations. On-road and Non-road mobile sources and ports were found to be the dominant sources of NO2, while O3 was mostly affected by organic solvents in Foshan. Controls on ports and the organic solvents are key to achieving a synergetic control of NO2 and O3 pollution in Foshan. About 2.5% and 2.0% reduction in NO2 and O3 concentrations, respectively, were found to require only a 3.6% reduction in NOx emissions from ports and a 10.6% reduction in VOC emission from organic solvents. In addition to the “double high” episode, this control scheme has been extended to verify the effects of NO2 and O3 pollution controls under various synoptic weather conditions.

The Outcome of Refractory or Relapsed but Not Refractory Diffuse Large B-Cell Lymphoma in China: Results from the Real-TREND Study

BACKGROUND. The definition and outcome of relapsed or refractory diffuse large B-cell lymphoma (DLBCL) have been ambiguous due to small sample sizes and varied definitions in previous studies[1]. The recent SCHOLAR-1 study[2] was the first large-scale analysis focusing on patients with refractory DLBCL. Patients with relapsed but not refractory DLBCL were not included in this study.OBJECTIVE. The primary objective is to further validate the outcome of SCHOLAR-1 study, including overall survival (OS) and response rate (RR) to salvage therapy, of patients with refractory DLBCL in a different geographical location. The secondary objective is to analyze the outcome (OS) of patients with relapsed but not refractory DLBCL.PATIENTS AND METHODS. Electronic health records of patients diagnosed with DLBCL and admitted to one of the 7 hospitals in 5 cities in southern China (Shanghai, Hangzhou, Chongqing, Wuhan, and Fuzhou) from 2010 to 2015 were reviewed. Structured data was manually collected according to a pre-defined data collection plan. Patients' survival statuses were regularly followed through telephone interviews. In this study, refractory DLBCL was defined as progressive or stable disease as the best response to any line of chemotherapy, and relapsed but not refractory DLBCL was define as a relapsed disease occurred without being refractory after disease remission. For patients with refractory DLBCL, OS was estimated from the time when the refractory status was determined. Among patients with relapsed but not refractory DLBCL, OS was estimated from the time of response evaluation in the last line of chemotherapy. RR to salvage therapy was only evaluated in patients with refractory DLBCL.RESULTS. Among 2,711 patients with DLBCL admitted to the 7 hospitals, 461 patients were refractory and 144 were relapsed but not refractory. For all 605 patients, the median OS was 16.8 (95% CI: 14.4-21.4) months and 2-year survival rate was 43.7% (95% CI: 39.7%-48.1%). Among patients with refractory DLBCL, the median OS was 12.3 (95% CI: 10.5, 14.4) months and 2-year survival rate was 33.8% (95% CI: 29.5%-38.8%). Among patients with relapsed but not refractory DLBCL, median OS was 82.6 (95% CI: 48.5-NA) months and 2-year survival rate was 73.9% (95% CI: 66.8%, 81.8%). Patients with refractory DLBCL had significantly inferior overall survival compared patients with relapsed but not refractory DLBCL (hazard ratio [HR] 2.92, 95% CI: 2.20-3.89, p value <0.001). Among patients with refractory DLBCL, the estimated RR was 28.56% (95% CI: 20.28%-36.84%) to the next line of therapy and the estimated complete response rate (CRR) was 7.90% (95% CI: 3.02%-12.79%). RR to salvage therapy was consistently poor among subgroups in patients with refractory DLBCL.CONCLUSION. The REAL-TREND study demonstrates poor survival and response to salvage therapy for patients with refractory DLBCL, which is consistent with the results of the SCHOLAR-1 study. But patients with relapsed but not refractory DLBCL have significantly greater chance of long-term survival.REFERENCE.Colosia A, Njue A, Trask PC, Olivares R, Khan S, Abbe A, et al. Clinical efficacy and safety in relapsed/refractory diffuse large B-cell lymphoma: a systematic literature review. Clinical lymphoma, myeloma & leukemia. 2014;14(5):343-55.e6. Epub 2014/04/29. doi: 10.1016/j.clml.2014.02.012. PubMed PMID: 24768510.Crump M, Neelapu SS, Farooq U, Van Den Neste E, Kuruvilla J, Westin J, et al. Outcomes in refractory diffuse large B-cell lymphoma: results from the international SCHOLAR-1 study. Blood. 2017;130(16):1800-8. Epub 2017/08/05. doi: 10.1182/blood-2017-03-769620. PubMed PMID: 28774879; PubMed Central PMCID: PMCPMC5649550. DisclosuresNo relevant conflicts of interest to declare.

Dynamics of nitrogen, phosphorus, and organic pollutant losses from a small watershed in the drinking-water source protection area in Guiyang City of Southern China.

Nutrients in runoff degrade water quality. The development of schemes to mitigate such degradation requires a characterization of the underlying dynamic processes of nutrient loss. The drinking-water source protection area in the Lake Hongfeng watershed of Guiyang City, the capital of Guizhou Province, China, has been delimited for effective conservation. However, no systematic observations have provided data on nutrient losses from these areas that could support optimal management. We selected one typical watershed in the area. Automatic gauges were installed to record the water levels and calculate runoff rates during 2010 and 2011. A total of 1523 runoff samples were collected at an interval of 3h during a day; total nitrogen (TN), total phosphorus (TP), and chemical oxygen demand (COD) were tested. The results indicated that surface runoff rates were primarily less than 15L/s but rapidly increased 1-30 times 15L/s when it rained. TN, TP, and COD concentrations primarily fluctuated between 0.06 and 18.79mg/L, between 0.01 and 1.57mg/L, and between 0.01 and 160mg/L, respectively. TN and COD concentrations in 98.98% and 52.04% of the runoff samples, respectively, exceeded the upper limit required by the Environmental Quality Standards for Surface Water (EQSSW) in China. Conversely, 94.29% of the runoff samples had lower concentrations than the upper limit of TP concentration. Surface runoff has been seriously polluted by nitrogen and organic pollutants. The occurrence frequency of different runoff rates and TP and COD concentrations showed different distributions, but TN concentrations had a normal distribution. There was a significant relationship between runoff rates and TP concentration and TN, TP, or COD loss. TN, TP, and COD loss primarily occurred on vegetable lands, rice fields, and residential sites. Effectively controlling nitrogen fertilizer that is applied on vegetable lands and paddy fields and managing wastewater and solid waste are urgent. The results reported here will also provide references for many other regions facing similar problems.

Effects of heat on first-ever strokes and the effect modification of atmospheric pressure: A time-series study in Shenzhen, China

BackgroundStroke is a leading cause of death globally. Extreme temperatures may induce stroke, but evidence on the effects of heat on first-ever strokes is not clear. Low air pressure can lead to depression and an increase in blood pressure, and it may exacerbate the health impact of heat. In this study, we aimed to evaluate the effects of heat on first-ever strokes, the possible sensitive populations, and the effect of modification of atmospheric pressure. MethodsWe collected data on 142,569 first-ever strokes during 2005–2016 in Shenzhen, a coastal city in southern China, with subtropical oceanic monsoon climate. We fitted a time-series Poisson model in our study, estimating the association between daily mean temperature and first-ever strokes in hot months, with a distributed lag non-linear model with 7 days of lag. We calculated strokes attributable to heat in various gender, age groups, household register types, stroke subtypes, and atmospheric pressure levels. ResultsHeat had a significant cumulative association with first-ever strokes, and the risk of strokes increased with the rise in temperature after it was higher than 30 °C (the 85th percentile). In total, 1.95% (95% empirical CI 0.63–3.20%) of first-ever strokes were attributable to high temperature. The attributable fraction and attributable number of heat were statistically significant in male, female, middle-aged and old patients, immigrant patients, and CBI patients. The fraction attributable to heat was 3.33% in the low atmospheric pressure group, and the number of estimated daily attributable strokes at low atmospheric pressure levels was higher than that of medium and high atmospheric pressure levels (p < 0.01). ConclusionsHigh temperatures in hot months may trigger first-ever strokes, and low atmospheric pressure may exacerbate the effect. We mainly found associations between heat and first-ever strokes for intracerebral hemorrhage, middle-aged and old patients, as well as immigrant patients.

Dog bite and injury awareness and prevention in migrant and left-behind children in China

Dog-incurred injury is a serious public health concern worldwide, especially for children, responsible for numerous infectious diseases, such as rabies. Our study aims to investigate the current status of dog-incurred injury and its prevention among special groups of children. A cross-sectional study was conducted among migrant children (MC) and non-MC, “left-behind” children (LBC) and non-LBC in two cities in southern China. A questionnaire was used to collect socio-demographic data and experience with dog-incurred injury, to assess knowledge of dog behaviour and rabies prevention and attitudes in risk identification and practice in risk behaviour. A total of 9,380 children aged 6–19 years old participated in this study. The self-reported prevalence of overall lifetime dog-incurred injuries in MC was 19.4% (vs. 11.2% in non-MC, χ2 = 175.8) and LBC was 20.6% (vs. 13.5% in non-LBC, χ2 = 114.1). MC were more likely to provoke a dog before the injury happened (12.7% vs 11.0%), while LBC (13.3% vs. 10.7%) and non-MC (13.1% vs. 12.2%) did not manage their wounds (all P < 0.001). 45.6% of victims were alone when the attack happened. MC from other provinces who live in rural areas and LBC with their mother absent had the lowest levels of knowledge among the groups. Taken together, MC and LBC are at greater risk for dog-incurred injury. They had lower knowledge of and attitudes towards prevention and more high-risk behaviour. Therefore, an appropriate public health education intervention is needed for schoolchildren regarding the prevention and management of dog-incurred injury and disease.

Differential patterns of nitrogen and δ15N in soil and foliar along two urbanized rivers in a subtropical coastal city of southern China

Urbanization usually pollutes the environment leading to alterations in key biogeochemical cycles. Therefore, understanding its effects on forest nitrogen (N) saturation is becoming increasingly important for addressing N pollution challenges in urban ecosystems. In this study, we compared soil (N availability, net N mineralization, net nitrification, and δ15N) and foliar (N concentrations and δ15N) variables in upstream, midstream and downstream forest stands of Bailongjiang River (BJR; more urbanized) and Wulongjiang River (WJR; less urbanized), the two branches of the Minjiang River Estuary. Total soil N, ammonium, nitrate, net N mineralization and nitrification rates, as well as soil δ15N were significantly higher in BJR compared with WJR forest stands. While no substantial difference in foliar N concentrations was noted between rivers, foliar δ15N was on average more than 2.5 times higher in BJR than WJR forest stands. Across the study area, foliar δ15N was positively related to soil δ15N, which also had positive linear relationships with soil nitrate concentrations, net N mineralization and net nitrification rates. Moreover, all variables except foliar δ15N and ammonium concentrations showed decreasing patterns in the order: upstream > midstream > downstream along the BJR forest stands. Soil ammonium and foliar values (N concentrations and δ15N) revealed clear patterns along the WJR, with the former increasing and the latter decreasing from the upstream to downstream forest stands. Our findings indicate an increase in urbanization-induced N inputs from the WJR to BJR and that forest stands along the BJR especially at the upstream have higher N availability and are shifting rapidly towards N saturation state. These results emphasize the need for effective N pollution control in urban environments through sustainable urban planning.

Association Between Environmental Factors and Oral Epstein-Barr Virus DNA Loads: A Multicenter Cross-sectional Study in China.

Oral Epstein-Barr virus (EBV) status reflects host EBV activity and potentially links to EBV-associated diseases, however, factors influencing oral EBV loads or reactivation, such as environmental exposures or host factors, are not fully understood. A 2-stage, multicenter, cross-sectional study of 6558 subjects from 21 administrative cities of southern China and 3 populations from representative geographical areas in China (referred to as the south, north, and northeastern populations) was performed. The relationships between demographical factors and environmental exposures to EBV loads were analyzed by logistic regression models. Current smoking, with a dose-response effect, was found to be strongly associated with higher oral EBV loads in the pooled data, with an odds ratio of 1.58 (95% confidence interval, 1.39-1.79), as well as in each of the separate populations. The odds ratio increased to 3.06 when current smokers in southern China were compared to never smokers in northern China. Additionally, higher oral EBV loads tended to be detected in older participants, male participants, and participants in southern China. This study provided evidence linking the effect of host-environmental factors, particularly smoking, to oral EBV activity. It could strengthen our understanding of the possible causal roles of EBV-related diseases, which may help to prevent or mitigate EBV-associated diseases.

Trend in the nutritional status of children aged 2-7 years in Luoding city, China: A panel study from 2004 to 2013.

To examine trends in the prevalence of wasting, stunting, overweight, and obesity among children in Luoding, a lower-middle-income city in southern China, we collected height, weight and other information on 65,908 pre-school children aged 2 to 7 years from 23 kindergartens, in which health examinations were conducted annually between 2004 and 2013. We used the growth standards of the World Health Organization (WHO) to calculate Z-scores for height and body mass index (BMI), and used the cut-offs recommended by WHO to define wasting, stunting, overweight, and obesity for each child. From 2004 to 2013, the prevalence of overweight increased from 3.70% to 7.27% and of obesity increased from 1.04% to 2.08%. Meanwhile, the prevalence of wasting decreased from 0.91% to 0.72% and of stunting decreased from 9.29% to 5.22%. These trends suggest there was still a double burden of nutritional status there. The nutritional interventions focusing on pre-school children should be comprehensively elaborated in lower-middle-income areas such as Luoding.

Everyday knowledge on the move: dynamic process and micro politics of the transfer of Guangchang wu

ABSTRACTThis article explores mobilities of everyday knowledge by analyzing the diffusion of northern aerobics, a particular form of Guangchang wu (plaza dance), from the Chinese mainland to Sanya, a coastal city in southern China. It understands mobile everyday knowledge as an ongoing process, and examines its dynamism by scrutinizing its complex and unstable routes, shaped by multiple agents and power relations. The transfer of northern aerobics undergoes continuous changes in its trajectories and is influenced by the discourse of professionalism, everyday leisure practices of Houniao, mainland migrants and local residents, and unequal interactions between the three groups of recreationists. The Houniao are mostly retirees from northern provinces, who undertake seasonal travel and pass winter in Sanya. Their regular and exclusive mobilities have greatly shaped the process of the transmission of leisure knowledge to Sanya and granted them privileged status in aerobic exercise. Nonetheless, mainland migrants, who have relocated in Sanya, begin to take on an increasing important role by changing the trajectories of knowledge diffusion. Through daily participation, local residents are also involved in reproducing the mobile leisure knowledge and negotiate a host identity. This article offers further insight into the dynamism and politics of knowledge diffusion in everyday life.

Interference identification in smart grid communications

The TD-LTE wireless private network for electric power systems is an important component of smart grids, and coverage analysis and interference identification are essential in operating and optimizing of power wireless private networks. This paper presents an approach to analyzing indoor and outdoor coverage scopes of cell radio signals and recognizing locations and sources of intra-network interference in the network deployed in a dense urban environment. This approach takes scenario modeling to represent terrain and on-ground objects given by digital maps, utilizes ray tracing to track the signal propagation trajectories, and calculates strength attenuation of radio signals due to signal propagation such as direct transmission, reflection, diffraction and refraction. The uniform grid is employed as the acceleration structure to speed up tracing signal propagation paths, and drive-testing measurement data and scenario-oriented propagation model calibration are used to improve analysis accuracy. Weak coverage spots and interference defect spots are defined and used to identify interference types and sources. We applied the approach to a tentative TD-LTE power wireless private network in a southern city in China, proving that the ray-tracing-based scheme is able to make precise analysis on coverage and interference in practical networks.