Search

Based on the analysis of the existing methods for estimating the surface flattening error, they can be roughly classified into two types of estimation methods: the relative area error analysis method and the relative length error analysis method. The advantages and disadvantages of these methods are summarized in the paper. Combining the general surface flattening methods and sheet metal stamping forming process, a more reasonable, scientific and comprehensive evaluation system for the accuracy of surface flattening is proposed. In line with the unfolding characteristics of the grid surface, the relative average area error of triangles is used instead of the traditional area error estimation method. The accumulated length error is replaced by the relative length error of each triangle in the estimation method, and the value of the change in the orientation (direction, position) relationship between the triangles is increased to assess the deformation error of the surface flattening method. The mass attributes of the patch are introduced. The minimum displacement energy method is used to supplement the evaluation of surface flattening accuracy. Finally, a comprehensive evaluation system is established and proposed, which takes into account the accuracy of local and global surface flattening.

LED is an extremely important energy-saving lighting products, which has greatly facilitated human life. Meanwhile, it also makes a positive contribution to global carbon neutrality and carbon peaking. Defect detection is a vital part of the production process to control the quality of LED chips. The traditional methods use a microscope for manual visual inspection, which is time-consuming and has inconsistent testing standards, low efficiency, and other deficiencies. To solve these problems, a hybrid algorithm based on geometric computation and a convolutional neural network is proposed for LED chip defect detection. The method takes advantage of the dimensionality reduction of geometric computation to perform coarse detection of defects on preprocessed chip lithography graphs in the form of grid segmentation, which realizes fast coarse screening of large-scale chip samples and reduces postcomputational costs. The convolutional neural network model is used for the secondary fine detection of "suspected defective" chips after geometric coarse screening, and the SPP (spatial pyramid pooling) network model is improved by directly introducing the original feature map into the SPP pooling layer for summation to enhance the global and local feature information of the output feature map. Furthermore, we construct an LED chip image acquisition platform using a high-frequency multimagnification zoom lens, collect training samples of defective chips, and increase the number of samples through image processing techniques. The research introduces the R-CNN, SDD, and YOLO methods to evaluate the superiority of our method in a number of experiments. The experimental results show that our algorithm proposed in this paper has an average precision (AP) of 96.7% for large-scale chip detection with a low defect rate. Compared with other methods, the testing mean average precision (mAP) is 10.39% higher than traditional YOLO v2. The testing mIoU is also 3.63% higher than traditional YOLO v5, the detection speed is also significantly improved, and it has good robustness. [ABSTRACT FROM AUTHOR]

In recent years, more and more attention has been paid to international education in schools in the USA. Education professionals, business leaders, and politicians realize that schools and school leaders must identify multiple opportunities for students to interact with and experience a global society. Nationally, there has been a considerable investment of funds by several key foundations and much political talk about the need to push American education towards a model of schooling that expressly responds to the need for internationally competent citizens. Using mixed methodology design, this study is fueled by a desire to better understand several overarching elements in international education. In short, the authors of this paper posit that no further research, policy formation, or program development within the realm of international education for public schools can be undertaken until an understanding of the current state of international education and the capacity for internationalization is empirically explored. (Contains 1 table and 2 notes.)

There have been ongoing discussions about the most recent curriculum reform in China. The new curriculum aims at a more quality-oriented ("suzhi") education and producing more well-rounded citizens to meet the challenges of global competition. However, it is questioned how "suzhi" education is possible with entrance examination still being the sole sorting mechanism. A semester-long ethnography in a rural middle school in northwest China reveals how rural students face many challenges with the new curriculum. Based on interviews, analyses of textbooks, and observations of classroom teaching, the study examines how rural students question the relevance of their curriculum and further the meaning of formal schooling. In addition to the dichotomy between an exam-oriented and quality-oriented curriculum, students are also troubled by the dichotomy between general/academic education and relevant/practical education. The study raises concerns about the urban-centered curriculum and how the rural community's absence in the picture has led to rural students' increasing disengagement in schooling and even dropout. It also reveals how the substance of "suzhi" education and the new curriculum have further reduced rural students' chance to move upward socially. The article concludes by pushing for discussions on how formal schooling can better serve rural children and youth. (Contains 3 notes.)

Based on an ethnographic study in a rural middle school in Northwest China, the author explores how the transition of the rural countryside, specifically townization, has challenged the urban-rural dichotomy being reproduced in and by formal schooling. Rural students express criticism of the chaos, pollution, and corruption they have experienced during townization, which also penetrate the school walls and become part of their daily schooling experience. Students' resistance to townization corresponds to their resistance to schooling. The author analyzes three groups of rural youth (conformists, reformers, and rebels), and how their resistance is limiting and even self-defeating, yet also has potential for being liberating.

Objective. This study focused on mood regulations and their association with sociodemographic status, exercise pattern, and physical conditions of adults and older adults in China who did not undergo interventions. Method. Data were based on the 2016 to 2018 Guangdong National Physique Monitoring data, in which 5242 participants aged 20-69 years were recruited. Multiple statistical analysis methods, such as descriptive and logistic regression analyses, were used to study each exercise motivation and its association with influencing factors, including sociodemographic characteristics, exercise measurements, and physical conditions. An exercise index for mental health was also used to investigate the number and types of people who were more likely to meet the index. Results. We observed that 44.9% (2355/5242) of participants did not engage in physical exercise in this study. Only older participants (40 to 69 years old) and those with an average level of education (high school/technical secondary school) showed a significant association with exercising for mood regulation. Few people met the index that is good for mental health (16.64% [872/5242] met index 1, and 2.84% (149/5242) met index 2), and higher education showed a significant association with a reduction in the mental health burden and the prevention of depression. Conclusion. This study found that motivating people to be more active and educating them on the potential mental health benefits of exercise could help them to exercise more. [ABSTRACT FROM AUTHOR]

Based on the analysis of the advantages and disadvantages of existing surface flattening algorithms, this paper proposes a free‐form surface flattening algorithm that minimizes geometric deformation by combining the advantages of the geometric flattening method and the mechanical energy flattening method to address the problems of many iterations, large changes in convergence, and weak visualization of deformation. The point cloud surface is meshed using the triangular slice search method, and the 3D surface mesh is wrapped around the surface using geometric mapping relationships. The initial correction and deformation analysis of the ring flatten graphic are carried out according to the average flattening error, and a global geometric deformation energy model is established to obtain the energy‐minimizing unfolding conditions and optimize the initial flattening graph by iterative optimization. The verification of the algorithm shows that the algorithm is general, has good robustness, high flattening accuracy, and visualizes the flattening deformation. The method is suitable for some design occasions of machining, such as the flattening calculation of automobile outer cladding parts and sheet metal parts. It is especially suitable for the flattening calculation of ring‐like parts, and is a good guide for the design calculation and stamping process of sheet‐metal‐like parts. [ABSTRACT FROM AUTHOR]

In order to improve the detection function of wearable intelligent devices in the Internet of things and facilitate people to control a variety of information such as heart rate, exercise state, blood oxygen saturation, and so on, the scientific detection of human physical health based on wearable devices based on Internet of things technology is proposed. Through the combination of software- and hardware-related functional modules, the real-time detection of human physical health information can be effectively realized. Firstly, the detection principle of optical capacitance product pulse wave signal and the waveform characteristics of pulse wave are introduced, and then the application scenarios and advantages of wearable devices are further introduced; then, the convolutional neural network for pulse wave signal denoising and the basic principle of self-encoder are introduced; finally, the regression prediction method and support vector machine method for pulse wave signal feature extraction are introduced in detail. The pulse wave based on optical capacitance product is removed to improve the waveform quality of pulse wave signal. Firstly, the system software development environment is briefly described. Then, the software design of watch terminal master device based on MSP432 and belt terminal slave device based on MSP430 are described in detail, and the detailed program implementation flow of each key technology in the system is given. In addition, the fall detection algorithm based on threshold discrimination is studied, and the program implementation of the algorithm is also described in detail. Finally, the system is tested. The results show that normal state mainly include normal walking, jogging, and fast sitting, and the accuracy rate is 97%, 95%, and 93%, respectively. For fall state, the experimenter needs to simulate various possible fall states, and the accuracy rate is 95%, 93%, and 95%, respectively, which verifies the detection accuracy of the algorithm. The system can automatically turn on the satellite positioning function when the user's physical sign parameters are abnormal or the user's current fall dangerous situation occurs, and send the current position information and alarm content information through the GSM module, so that the dangerous situation can be found and handled at the first time. [ABSTRACT FROM AUTHOR]

Objective: The aim was to study whether the computed tomography (CT) density and β-amyloid (Aβ) level of intraorbital optic nerve could assist in diagnosing mild cognitive impairment (MCI) and Alzheimer's disease (AD). Methods: A total of sixty subjects were recruited in our study, including nine normal control (NC) subjects (i.e., 4 men and 5 women), twenty four MCI subjects (i.e., 11 men and 13 women), and twenty seven AD subjects (i.e., 14 men and 13 women). All subjects conducted 18F-flutemetamol amyloid positron emission tomography (PET)/CT imaging. Blinded to the clinical information of the subjects, two physicians independently measured and calculated the standardized uptake value ratio (SUVR) of the bilateral occipital cortex, SUVR of the bilateral intraorbital optic nerve, and CT density of the bilateral intraorbital optic nerve by using GE AW 4.5 Workstation. Results: Between AD and NC groups, the differences of the bilateral intraorbital optic nerve SUVR were statistically significant; between AD and MCI groups, the differences of the left intraorbital optic nerve SUVR were statistically significant. Between any two of the three groups, the differences in the bilateral intraorbital optic nerve density were statistically significant. The bilateral occipital SUVR was positively correlated with the bilateral intraorbital optic nerve SUVR and negatively correlated with the bilateral intraorbital optic nerve density. Bilateral intraorbital optic nerve SUVR was negatively correlated with the bilateral intraorbital optic nerve density. The area under the receiver operating characteristic (ROC) curve of multiple logistic regression was 0.9167 (for MCI vs. NC) and 0.8951 (for AD vs. MCI). The Montreal Cognitive Assessment (MoCA) and Mini-Mental State Examination (MMSE) scores were positively associated with the intraorbital optic nerve density and were negatively associated with the intraorbital optic nerve SUVR. The regression equation of MoCA was y = 16.37-0.9734 × x 1 + 0.5642 × x 2-3.127 × x 3 + 0.0275 × x 4; the R 2 was 0.848. The regression equation of MMSE was y = 19.57-1.633 × x 1 + 0.4397 × x 2-1.713 × x 3 + 0.0424 × x 4; the R 2 was 0.827. Conclusion: The CT density and Aβ deposition of the intraorbital optic nerve were associated with Aβ deposition of the occipital cortex and the severity of cognitive impairment. The intraorbital optic nerve CT density and intraorbital optic nerve Aβ deposition could assist in diagnosing MCI and AD. [ABSTRACT FROM AUTHOR]

This paper provides an in-depth study and analysis of robot vision features for predictive control and a global calibration of their feature completeness. The acquisition and use of the complete macrofeature set are studied in the context of a robot task by defining the complete macrofeature set at the level of the overall purpose and constraints of the robot vision servo task. The visual feature set that can fully characterize the macropurpose and constraints of a vision servo task is defined as the complete macrofeature set. Due to the complexity of the task, a part of the features of the complete macrofeature set is obtained directly from the image, and another part of the features is obtained from the image by inference. The task is guaranteed to be completely based on a robust calibration-free visual serving strategy based on interference observer that is proposed to complete the visual serving task with high performance. To address the problems of singular values, local minima, and insufficient robustness in the traditional scale-free vision servo algorithm, a new scale-free vision servo method is proposed to construct a dual closed-loop vision servo structure based on interference observer, which ensures the closed-loop stability of the system through the Q-filter-based interference observer, while estimating and eliminating the interference consisting of hand-eye mapping model uncertainty and controlled robot input interference. The equivalent interference consisting of hand-eye mapping model uncertainty, controlled robot input interference, and detection noise is estimated and eliminated to obtain an inner-loop structure that presents a nominal model externally, and then an outer-loop controller is designed according to the nominal model to achieve the best performance of the system dynamic performance and robustness to optimally perform the vision servo task. [ABSTRACT FROM AUTHOR]

The packing for two-dimensional irregular graphics is one of the NP-complete problems and widely used in industrial applications. In this paper, a descending nesting algorithm for a two-dimensional irregular graph based on geometric feature points is proposed. Before the packing, the parts to be packed are sorted, matched, and spliced, and the matching of the rectangular pieces and the rectangular-like pieces is carried out according to the plate size. On this basis, the geometric feature points of the parts are used to construct the packing baseline, and the packing is accurately carried out according to the principles of the bottom left, the principle of the lowest center of gravity, and combination with virtual moving, rotating collision calculation. The computation of the moving collision distance between the graphics is replaced by the projecting computation of the geometric feature points of the graphic parts, so the computation amount can be reduced. Also, this method is used to test a number of benchmarks examples which are provided by ESICUP (EURO Special Interest Group on Cutting and Packing), which show that the proposed algorithm not only can improve packing but also has better stability and reliability. [ABSTRACT FROM AUTHOR]

Objectives: To assess the efficacy and safety of 99mTc-TRODAT-1 SPECT in diagnosing Parkinson's disease (PD).Methods: 99mTc-TRODAT-1 SPECT imaging was performed in 34 healthy controls and 96 PD patients 2.5 h later after injection. The striatal image was evaluated visually and semi-quantitively. Sensitivity and specificity of 99mTc-TRODAT-1 SPECT were analyzed according to Hoehn and Yahr scale (HYS). Based on HYS, the PD patients were divided into mild (HYS 1-2) and moderate (HYS 3-5) groups. The uptake ratios of striatum (ST) and cerebellum (CB) in contralateral, ipsilateral and bilateral striatum in different groups were calculated and analyzed. The safety was assessed.Results: The sensitivity and specificity of 99mTc-TRODAT-1 SPECT to discriminate PD patients from healthy subjects were 98.96% and 94.12% and it has perfect agreement with HYS (κ = 0.94, p < 0.001). The sensitivity to diagnose mild and moderate PD was 43.42% and 95% separately. The uptake ratio in PD patients was significantly lower than that in healthy controls (1.37 ± 0.13 vs 1.68 ± 0.18, p < 0.001). And the uptake ratio in contralateral side was markedly reduced in unilateral PD patients as compared with the ipsilateral side (1.50 ± 0.20 vs 1.46 ± 0.21, p < 0.001). The striatal uptakes in affected striatum and bilateral striatum were reduced with increasing disease severity between healthy control versus mild stage versus moderate stage in the affected striatum and bilateral striatum in PD patients. No serious adverse events or death was observed after injecting 99mTc-TRODAT-1.Conclusion: We demonstrated that 99mTc-TRODAT-1 was a safety radiotracer which can be used in clinic to diagnose PD using SPECT. [ABSTRACT FROM AUTHOR]

In recent years, more and more attention has been paid to international education in schools in the USA. Education professionals, business leaders, and politicians realize that schools and school leaders must identify multiple opportunities for students to interact with and experience a global society. Nationally, there has been a considerable investment of funds by several key foundations and much political talk about the need to push American education towards a model of schooling that expressly responds to the need for internationally competent citizens. Using mixed methodology design, this study is fueled by a desire to better understand several overarching elements in international education. In short, the authors of this paper posit that no further research, policy formation, or program development within the realm of international education for public schools can be undertaken until an understanding of the current state of international education and the capacity for internationalization is empirically explored. [ABSTRACT FROM AUTHOR]

There have been ongoing discussions about the most recent curriculum reform in China. The new curriculum aims at a more quality-oriented (suzhi) education and producing more well-rounded citizens to meet the challenges of global competition. However, it is questioned how suzhi education is possible with entrance examination still being the sole sorting mechanism. A semester-long ethnography in a rural middle school in northwest China reveals how rural students face many challenges with the new curriculum. Based on interviews, analyses of textbooks, and observations of classroom teaching, the study examines how rural students question the relevance of their curriculum and further the meaning of formal schooling. In addition to the dichotomy between an exam-oriented and quality-oriented curriculum, students are also troubled by the dichotomy between general/academic education and relevant/practical education. The study raises concerns about the urban-centered curriculum and how the rural community's absence in the picture has led to rural students' increasing disengagement in schooling and even dropout. It also reveals how the substance of suzhi education and the new curriculum have further reduced rural students' chance to move upward socially. The article concludes by pushing for discussions on how formal schooling can better serve rural children and youth. [ABSTRACT FROM AUTHOR]

Based on an ethnographic study in a rural middle school in Northwest China, the author explores how the transition of the rural countryside, specifically townization, has challenged the urban–rural dichotomy being reproduced in and by formal schooling. Rural students express criticism of the chaos, pollution, and corruption they have experienced during townization, which also penetrate the school walls and become part of their daily schooling experience. Students’ resistance to townization corresponds to their resistance to schooling. The author analyzes three groups of rural youth (conformists, reformers, and rebels), and how their resistance is limiting and even self-defeating, yet also has potential for being liberating. [ABSTRACT FROM PUBLISHER]

Objective: Patent foramen ovale (PFO) has been regarded as a potential source of cryptogenic stroke, which was conventionally detected by transesophageal echocardiography. Cardiac computed tomography (CCT) is a promising, noninvasive test for detection of PFO. We sought to conduct a meta-analysis to evaluate the diagnostic performance of CCT in detecting PFO., Methods: PubMed, ISI Web of Knowledge, Embase, Cochrane Library, and Wanfang from inception to June 2020 were searched for relevant studies comparing CCT and transesophageal echocardiography as the reference standard in detecting PFO. A bivariate model was used to pool sensitivity and specificity and to construct summary receiver operating characteristic (SROC) curves., Results: A total of seven studies with 483 patients were included in this meta-analysis. For the diagnosis of PFO, CCT had a mean sensitivity and specificity of 0.70 [95% CI:0.58, 0.79] and 0.97 [95% CI: 0.95, 0.99]. The SROC analysis showed an area under the curve of 0.97., Conclusion: CCT shows good diagnostic accuracy in detecting PFO with relatively high sensitivity and specificity. CCT could be considered a noninvasive alternative to transesophageal echocardiography for detecting PFO.

Objective: The aim was to study whether the computed tomography (CT) density and β-amyloid (Aβ) level of intraorbital optic nerve could assist in diagnosing mild cognitive impairment (MCI) and Alzheimer's disease (AD)., Methods: A total of sixty subjects were recruited in our study, including nine normal control (NC) subjects (i.e., 4 men and 5 women), twenty four MCI subjects (i.e., 11 men and 13 women), and twenty seven AD subjects (i.e., 14 men and 13 women). All subjects conducted 18 F-flutemetamol amyloid positron emission tomography (PET)/CT imaging. Blinded to the clinical information of the subjects, two physicians independently measured and calculated the standardized uptake value ratio (SUVR) of the bilateral occipital cortex, SUVR of the bilateral intraorbital optic nerve, and CT density of the bilateral intraorbital optic nerve by using GE AW 4.5 Workstation., Results: Between AD and NC groups, the differences of the bilateral intraorbital optic nerve SUVR were statistically significant; between AD and MCI groups, the differences of the left intraorbital optic nerve SUVR were statistically significant. Between any two of the three groups, the differences in the bilateral intraorbital optic nerve density were statistically significant. The bilateral occipital SUVR was positively correlated with the bilateral intraorbital optic nerve SUVR and negatively correlated with the bilateral intraorbital optic nerve density. Bilateral intraorbital optic nerve SUVR was negatively correlated with the bilateral intraorbital optic nerve density. The area under the receiver operating characteristic (ROC) curve of multiple logistic regression was 0.9167 (for MCI vs. NC) and 0.8951 (for AD vs. MCI). The Montreal Cognitive Assessment (MoCA) and Mini-Mental State Examination (MMSE) scores were positively associated with the intraorbital optic nerve density and were negatively associated with the intraorbital optic nerve SUVR. The regression equation of MoCA was y = 16.37-0.9734 × x 1 + 0.5642 × x 2 -3.127 × x 3 + 0.0275 × x 4 ; the R 2 was 0.848. The regression equation of MMSE was y = 19.57-1.633 × x 1 + 0.4397 × x 2 -1.713 × x 3 + 0.0424 × x 4 ; the R 2 was 0.827., Conclusion: The CT density and Aβ deposition of the intraorbital optic nerve were associated with Aβ deposition of the occipital cortex and the severity of cognitive impairment. The intraorbital optic nerve CT density and intraorbital optic nerve Aβ deposition could assist in diagnosing MCI and AD., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. JZ declared a shared parent affiliation with XL at the time of review., (Copyright © 2022 Wu, Lei, Ou, Shi, Xu, Shi, Ding, Zhao, Wang, Cai, Liu, Lou and Liu.)

Evolve and resequencing (E&R) was applied to lab adaptation of Toxoplasma gondii for over 1,500 generations with the goal of mapping host-independent in vitro virulence traits. Phenotypic assessments of steps across the lytic cycle revealed that only traits needed in the extracellular milieu evolved. Nonsynonymous single-nucleotide polymorphisms (SNPs) in only one gene, a P4 flippase, fixated across two different evolving populations, whereas dramatic changes in the transcriptional signature of extracellular parasites were identified. Newly developed computational tools correlated phenotypes evolving at different rates with specific transcriptomic changes. A set of 300 phenotype-associated genes was mapped, of which nearly 50% is annotated as hypothetical. Validation of a select number of genes by knockouts confirmed their role in lab adaptation and highlights novel mechanisms underlying in vitro virulence traits. Further analyses of differentially expressed genes revealed the development of a "pro-tachyzoite" profile as well as the upregulation of the fatty acid biosynthesis (FASII) pathway. The latter aligned with the P4 flippase SNP and aligned with a low abundance of medium-chain fatty acids at low passage, indicating this is a limiting factor in extracellular parasites. In addition, partial overlap with the bradyzoite differentiation transcriptome in extracellular parasites indicated that stress pathways are involved in both situations. This was reflected in the partial overlap between the assembled ApiAP2 and Myb transcription factor network underlying the adapting extracellular state with the bradyzoite differentiation program. Overall, E&R is a new genomic tool successfully applied to map the development of polygenic traits underlying in vitro virulence of T. gondii. IMPORTANCE It has been well established that prolonged in vitro cultivation of Toxoplasma gondii augments progression of the lytic cycle. This lab adaptation results in increased capacities to divide, migrate, and survive outside a host cell, all of which are considered host-independent virulence factors. However, the mechanistic basis underlying these enhanced virulence features is unknown. Here, E&R was utilized to empirically characterize the phenotypic, genomic, and transcriptomic changes in the non-lab-adapted strain, GT1, during 2.5 years of lab adaptation. This identified the shutdown of stage differentiation and upregulation of lipid biosynthetic pathways as the key processes being modulated. Furthermore, lab adaptation was primarily driven by transcriptional reprogramming, which rejected the starting hypothesis that genetic mutations would drive lab adaptation. Overall, the work empirically shows that lab adaptation augments T. gondii's in vitro virulence by transcriptional reprogramming and that E&R is a powerful new tool to map multigenic traits.