Explaining Rising Returns to Education in Urban China in the 1990s

Although theory predicts that international trade will decrease the relative demand for skilled workers in relatively skill-deficit countries, in recent decades many developing countries have experienced rising wage premiums for skilled workers. We examines this puzzle by quantifying the relative importance of different supply and demand factors in explaining the rapid increase in the returns to education experienced by China during the 1990s. Analyzing Chinese urban household survey and census data for six provinces, we find that although changes in the structure of demand did reduce the demand for skilled workers, consistent with trade theory, the magnitude of the effect was modest and more than offset by institutional reforms and technological changes that increased the relative demand for skill.education, earnings, inequality, China

Investigation on Performance of a Converted Remote Sensing System for Diesel Tailpope Emissions Monitoring

Roadside remote sensing (RS) has been adopted by the environmental protection department of Hong Kong as a tool for controlling urban air quality issues induced by on-road vehicles. The technology provides the unique advantage of being able to scan a large number of vehicles without interfering the traffic. The horizontal or cross-road RS (HRS) devices in used today are mostly tailored for single-lane applications. where the path of the RS light beam is parallel to the road surface, and emission scanning are limited to some segments of the roadway network. Vertical remote sensing (VRS) that scans an exhaust plume with a light beam perpendicular to the road surface has been proposed for multiple-lane applications but published results are scarce. VRS offers the advantage of being able to distinguish the plumes of different vehicles [1] but comes with some snags associated with installation, protection, and maintenance of the ground unit. A diagonal remote sensing (DRS) system is a modified version of the conventional RS with the light source and the detector unit (the main unit) lifted and tilted to scan the exhaust plume of a passing car diagonally and the ground unit titled to deflect the light back to the main unit. Such setup could prevent the ground unit being drove over and, therefore, reduce the needs to protect and maintain the ground unit. Plume dispersion models of box trailer trucks revealed that an area of recirculation appear at the close vicinity of the back of the trucks [2, 3]. The tilt angle of the DRS could be adjusted to scan the recirculation pockets of different types of vehicle. This study aims at evaluating the performance of a DRS prototype system that was converted from conventional RS devices in detecting exhaust emissions from a diesel truck, comparing the performance of DRS to those of HRS and VRS, and determining the feasibility of deploying DRS in single-lane applications. The RS systems measured the tailpipe emissions from a designated diesel vehicle equipped with portable emission measurement systems (PEMS) under a range of loading and driving conditions (i.e., 0 — 50% load and 10 — 30 km/h). The average NOx to CO2 ratio recorded by the HRS, VRS, and DRS systems were 44% (+ 6%), 32% (+ 4.5%), and 36% (+ 5.7%) of the PEMS equivalent measurements, respectively. The linear regression analyses of the HRS-PEMS pair, VRS-PEMS pair, and DRS-PEMS pair in terms of NOx/CO2 revealed that the correlation between HRS-PEMS is the most significant followed by VRS and DRS. The average NOx signal magnitude of the HRS, VRS, and DRS systems were 0.52, 0.61, and 0.21, respectively. It is concluded that the performance of the proposed DRS system is comparable to the performances of the HRS and VRS systems and DRS could be an opportunity to expand the role of RS in urban air quality control. ‘The work described in this study was fully supported by a grant from the Research Grants Council of the Hong Kong Special Administrative Region, China (Project No. UGC/IDS(c)25/E02/19)

Learn More for Food Recognition via Progressive Self-Distillation

Food recognition has a wide range of applications, such as health-aware recommendation and self-service restaurants. Most previous methods of food recognition firstly locate informative regions in some weakly-supervised manners and then aggregate their features. However, location errors of informative regions limit the effectiveness of these methods to some extent. Instead of locating multiple regions, we propose a Progressive Self-Distillation (PSD) method, which progressively enhances the ability of network to mine more details for food recognition. The training of PSD simultaneously contains multiple self-distillations, in which a teacher network and a student network share the same embedding network. Since the student network receives a modified image from its teacher network by masking some informative regions, the teacher network outputs stronger semantic representations than the student network. Guided by such teacher network with stronger semantics, the student network is encouraged to mine more useful regions from the modified image by enhancing its own ability. The ability of the teacher network is also enhanced with the shared embedding network. By using progressive training, the teacher network incrementally improves its ability to mine more discriminative regions. In inference phase, only the teacher network is used without the help of the student network. Extensive experiments on three datasets demonstrate the effectiveness of our proposed method and state-of-the-art performance.Comment: Accepted by AAAI 202

THE EFFECT OF TRUST ON INFORMATION DIFFUSION IN ONLINE SOCIAL NETWORKS

online social networks have a explosive growth in recent years and they provide a perfect platform for information diffusion. Many models have been given to explore the information diffusion procedure and its dynamics. But the trust relationship and memory effect are ignored. Based on the complex network theory, The information diffusion model is proposed and the network users, considered as agents, are classified into susceptible, infected and recovered individuals. The users’ behaviour rule and diffusion process are designed. The proposed agent-based model is tested by simulation experiments in four different complex networks: regular network, small world network, random network and scale-free network. Moreover, the effect of four immunization strategies are explored. The research results show that the influence of users’ trust relationship on different networks is varied, and the vertex weight priority immunization strategy is the best one in all four networks

Feature-Suppressed Contrast for Self-Supervised Food Pre-training

Most previous approaches for analyzing food images have relied on extensively annotated datasets, resulting in significant human labeling expenses due to the varied and intricate nature of such images. Inspired by the effectiveness of contrastive self-supervised methods in utilizing unlabelled data, weiqing explore leveraging these techniques on unlabelled food images. In contrastive self-supervised methods, two views are randomly generated from an image by data augmentations. However, regarding food images, the two views tend to contain similar informative contents, causing large mutual information, which impedes the efficacy of contrastive self-supervised learning. To address this problem, we propose Feature Suppressed Contrast (FeaSC) to reduce mutual information between views. As the similar contents of the two views are salient or highly responsive in the feature map, the proposed FeaSC uses a response-aware scheme to localize salient features in an unsupervised manner. By suppressing some salient features in one view while leaving another contrast view unchanged, the mutual information between the two views is reduced, thereby enhancing the effectiveness of contrast learning for self-supervised food pre-training. As a plug-and-play module, the proposed method consistently improves BYOL and SimSiam by 1.70\% $\sim$ 6.69\% classification accuracy on four publicly available food recognition datasets. Superior results have also been achieved on downstream segmentation tasks, demonstrating the effectiveness of the proposed method.Comment: Accepted by ACM MM 202

Compreendendo mudanças no comportamento de risco moral médico em resposta a reforma governamental de cuidados à saúde

Doctor moral hazard has a significant effect on the doctor-patient relationship, increases the cost of healthcare, and introduces medical risks. It is a global concern. Doctor moral hazard behaviour is evolving in response to China’s healthcare reform program which was inaugurated in 2009.A scientific understanding of doctor behaviour would facilitate the prevention and control of doctor moral hazard behaviour. This study used the principles and methodology of Glaser and Strauss’s grounded theory. Theoretical and snowball samplings were used to identify 60 subjects. Semi-structured in-depth interviews were conducted with each subject. Themes were identified through substantial (open) coding and theoretical coding. Six types of doctor moral hazard behaviour were extracted from the data. A behavioural model was described and diagrammed to provide a conceptual framework of current doctor moral hazard behaviour. The conceptual model of doctor moral hazard behaviour can be used in several ways to correct or prevent undesirable actions. Rules governing hospital procedures can be strengthened and enforced by supervision and punishment; the asymmetry of information between doctor and patient can be reduced; patient participation in treatment decisions can be increased; the effectiveness of medical ethics education can be improved.Para un médico, el riesgo moral tiene un efecto significativo en la relación médico-paciente, incrementa el costo de la atención de salud e introduce riesgos en la salud. Se trata de una preocupación global. El riesgo moral del comportamiento médico ha evolucionado en respuesta al programa de reforma de atención de salud del gobierno de China, inaugurado en 2009. Un entendimiento científico del comportamiento de los médicos facilitaría la prevención y el control del riesgo moral. El presente estudio usa los principios y metodología de la teoría fundamentada de Glaser y Strauss. Se usaron muestras teóricas y multiplicativas para identificar 60 sujetos y realizar entrevistas semiestructuradas en profundidad. Los temas se identificaron mediante codificación sustancial abierta y teórica. De los datos se extrajeron seis tipos de riesgo moral del comportamiento médico. Se describió y diagramó un modelo de comportamiento para proporcionar una estructura conceptual del riesgo moral del comportamiento médico actual. El modelo conceptual de riesgo moral del comportamiento médico puede usarse de varias maneras para corregir o prevenir acciones no deseadas. Las normas procedimentales de los hospitales pueden fortalecerse y exigirse mediante supervisión y castigo; se puede reducir la asimetría de la información que se da entre el médico y el paciente, incrementar la participación del pacieRisco moral médico tem um efeito significativo na relação médico-paciente, aumenta o custo dos cuidados à saúde e introduz riscos médicos. É uma preocupação global. Comportamento de risco moral médico vem se desenvolvendo em resposta ao programa de reforma de cuidados à saúde da China, que se iniciou em 2009. Uma compreensão científica do comportamento médico facilitaria a prevenção e controle do comportamento de risco moral médico. Este estudo utilizou os princípios da metodologia da Teoria Fundamentada de Glaser e Strauss. Amostragem teóricas e por bola de neve foram utilizadas para identificar 60 participantes. Entrevistas detalhadas semi-estruturadas foram realizadas com cada participante. Temas foram identificados através de codificação (aberta) substancial e codificação teórica. Seis tipos de comportamento de risco moral médico foram obtidos dos dados. Um modelo comportamental foi descrito e diagramado de forma a fornecer um enquadre conceitual do comportamento de risco moral médico. O modelo conceitual de comportamento de risco moral médico pode ser utilizado de diversas formas para corrigir ou prevenir ações indesejáveis. Regras que governam procedimentos em hospitais podem ser fortalecidas e reforçadas por supervisão e punição; a assimetria de informações entre médicos e pacientes pode ser reduzida; a participação dos pacientes nas decisões sobre tratamento pode ser aumentada; e a efetividade da educação ética médica pode ser melhorada

Air permeability of thermally modified hemlock wood

Western hemlock (Tsuga heterophylla) is a prevalent coastal species in British Columbia (BC). Its wood has a high potential for thermal modification, a process that can affect numerous physical properties, including air permeability. The current study investigates the longitudinal air permeability of hemlock wood modified at three temperature levels, 170 °C, 212 °C, and 230 °C, and a two-hour treatment length. Permeability values obtained using Darcy’s law and the water-falling volume displacement method were positively correlated with treatment temperature up to 212 °C, after which the permeability decreased slightly. ANOVA followed by the Duncan test revealed that thermal treatment at 212 °C and 230 °C significantly increased air permeability, whereas it was insignificant at 170 °C