bluuebunny/crossref_metadata_2025 huggingface dataset:
Bigger Than Life
Authors: Doane Mary Ann
Published: October 2021

In Bigger Than Life Mary Ann Doane examines how the scalar operations of cinema, especially those of the close-up, disturb and reconfigure the spectator's sense of place, space, and orientation. Doane traces the history of scalar transformations from early cinema to the contemporary use of digital technology. In the early years of cinema, audiences regarded the monumental close-up, particularly of the face, as grotesque and often horrifying, even as it sought to expose a character's interiority through its magnification of detail and expression. Today, large-scale technologies such as IMAX and surround sound strive to dissolve the cinematic frame and invade the spectator's space, “immersing” them in image and sound. The notion of immersion, Doane contends, is symptomatic of a crisis of location in technologically mediated space and a reconceptualization of position, scale, and distance. In this way, cinematic scale and its modes of spatialization and despatialization have shaped the modern subject, interpolating them into the incessant expansion of commodification.
The Lettered Barriada
Authors: Meléndez-Badillo Jorell A.
Published: October 2021

In The Lettered Barriada, Jorell A. Meléndez-Badillo tells the story of how a cluster of self-educated workers burst into Puerto Rico's world of letters and navigated the colonial polity that emerged out of the 1898 US occupation. They did so by asserting themselves as citizens, producers of their own historical narratives, and learned minds. Disregarded by most of Puerto Rico's intellectual elite, these workers engaged in dialogue with international peers and imagined themselves as part of a global community. They also entered the world of politics through the creation of the Socialist Party, which became an electoral force in the first half of the twentieth century. Meléndez-Badillo shows how these workers produced, negotiated, and deployed powerful discourses that eventually shaped Puerto Rico's national mythology. By following these ragtag intellectuals as they became politicians and statesmen, Meléndez-Badillo also demonstrates how they engaged in racial and gender silencing, epistemic violence, and historical erasures in the fringes of society. Ultimately, The Lettered Barriada is about the politics of knowledge production and the tensions between working-class intellectuals and the state.

Duke University Press Scholars of Color First Book Award recipient
Few-shot learning for deformable image registration in 4DCT images
Authors: Chi Weicheng , Xiang Zhiming , Guo Fen
Published: October 2021

Objectives:

To develop a rapid and accurate 4D deformable image registration (DIR) approach for online adaptive radiotherapy.

Methods:

We propose a deep learning (DL)-based few-shot registration network (FR-Net) to generate deformation vector fields from each respiratory phase to an implicit reference image, thereby mitigating the bias introduced by the selection of reference images. The proposed FR-Net is pretrained with limited unlabeled 4D data and further optimized by maximizing the intensity similarity of one specific four-dimensional computed tomography (4DCT) scan. Because of the learning ability of DL models, the few-shot learning strategy facilitates the generalization of the model to other 4D data sets and the acceleration of the optimization process.

Results:

The proposed FR-Net is evaluated for 4D groupwise and 3D pairwise registration on thoracic 4DCT data sets DIR-Lab and POPI. FR-Net displays an averaged target registration error of 1.48 mm and 1.16 mm between the maximum inhalation and exhalation phases in the 4DCT of DIR-Lab and POPI, respectively, with approximately 2 min required to optimize one 4DCT. Overall, FR-Net outperforms state-of-the-art methods in terms of registration accuracy and exhibits a low computational time.

Conclusion:

We develop a few-shot groupwise DIR algorithm for 4DCT images. The promising registration performance and computational efficiency demonstrate the prospective applications of this approach in registration tasks for online adaptive radiotherapy.

Advances in knowledge:

This work exploits DL models to solve the optimization problem in registering 4DCT scans while combining groupwise registration and few-shot learning strategy to solve the problem of consuming computational time and inferior registration accuracy.
Collaboration between an NHS University Teaching Hospital and independent hospital to maintain CT colonography service provision during the 2020 COVID-19 pandemic
Authors: Holland Paul , De Abreu Deborah , Higashi Yutaro , Clarke Christopher GD
Published: October 2021

Our trust performed CTCs at 93% of the capacity of the previous year, scanning 1265 patients in 2020, compared with 1348 in 2019. We describe the changes made to our service to achieve this, which included collaboration with the colorectal surgical team to prioritise existing CTC patients according to faecal-immunochemical tests and full blood count results, and the associated challenges which included image transfer delays and patient attendance for scans. Furthermore, the endoscopy and radiology services used the opportunity created by co-location at the same hospital site to provide a same day incomplete colonoscopy and staging service for optically confirmed cancers.

Collaboration between the NHS and independent sector allowed us to achieve continuity of service provision during the height of the COVID-19 pandemic without substituting unprepared CT abdomen and pelvis instead of the more sensitive CTC.
Towards reimagined technical assistance: the current policy options and opportunities for change
Authors: Nastase Alexandra , Rajan Alok , French Ben , Bhattacharya Debarshi
Published: October 2021

Technical assistance has been at the heart of development assistance provided to country governments by donor agencies over the past several decades. The current debates on reimagining technical assistance focus on the existing challenges of the different types of technical assistance and the (re)construction of an ideal model for delivering this type of support, with little discussion about the dilemmas involved in making day-to-day decisions and trade-offs in implementation. This article presents technical assistance as a policy option for governments and details the existing models of delivering technical assistance, their limitations, and the required enabling conditions. The models presented focus on the type of role for the technical advisers- as doers (performing government functions), partners (working with the government to perform a specific role) and facilitators (enabling and facilitating change programmes to address wicked problems). Finally, the paper provides a practical account of the implications of the programme design and suggests potential opportunities for change particularly in the context of COVID-19 pandemic. It complements an open letter on the practical account of the current challenges in the design and implementation of technical assistance programmes.
Hydroksykwasy organiczne w fitokosmetykach rewitalizujących
Authors: Kaniewska Agata , Sperkowska Beata
Published: October 2021

W artykule wyjaśniono zagadnienia związane z występowaniem i zastosowaniem hydroksykwasów organicznych w fitokosmetykach rewitalizujących i zabiegach kosmetycznych. Dokonano charakterystyki budowy skóry oraz właściwości fizycznych i chemicznych alfa-(AHA) i beta-hydroksykwasów (BHA) (kwas glikolowy, kwas mlekowy, kwas cytrynowy, kwas jabłkowy, kwas winowy, kwas salicylowy). Scharakteryzowano sposoby oznaczania hydroksykwasów, a także przedstawiono regulacje prawne dotyczące stosowania hydroksykwasów w kosmetykach. Przedstawiono wskazania i przeciwwskazania do zastosowania zabiegów z kwasami owocowymi. Opisano czynniki warunkujące skuteczność działania biologicznego alfa-hydroksykwasów (AHA).
Wybrane aspekty dziejów badań leczniczych roślin pasożytniczych w ujęciu filozoficznym
Authors: Różański Henryk , Czerny Edyta
Published: October 2021

Artykuł dotyczy analizy dziejów badań biologicznych i zastosowań terapeutycznych wybranych krajowych gatunków roślin pasożytniczych i półpasożytniczych. Omawia także wpływ różnych nauk przyrodniczych i medycznych na przebieg badań roślin pasożytniczych oraz przedstawia dzieje badań roślin leczniczych na tle historii botaniki.
Pomoc publiczna dla przedsiębiorców przed oraz w okresie trwania pandemii COVID-19
Authors: Żochowski Wiktor
Published: October 2021

Zagadnienie pomocy publicznej w 2020 roku nabrało jeszcze większego znaczenia niż miało to miejsce dotychczas. W Polsce jednym ze skutków pandemii wirusa SARS-CoV-2 był lockdown, czyli zakaz swobodnego poruszania się obywateli powiązany z różnorodnymi nakazami, jak np. nakazem zasłaniania ust i nosa w miejscach publicznych. Efektem działań państwa było zamrożenie gospodarki oraz widmo kryzysu gospodarczego. Autor artykułu w swojej pracy zamierza podjąć się oceny działań instytucji państwowych w trakcie pandemii oraz przeanalizować historię i rozwój pojęcia pomocy publicznej w Polsce zarówno przed regulacjami wprowadzonymi na mocy Układu Europejskiego jak i po wstąpieniu do Unii Europejskiej.
Przesłanki utworzenia samorządu zawodowego instruktorów nauki jazdy i egzaminatorów prawa jazdy w świetle art. 17 ust. 1 Konstytucji Rzeczypospolitej Polskiej
Authors: Wilczyński Karol
Published: October 2021

Przedmiotem rozważań autora artykułu są przesłanki utworzenia samorządu zawodowego instruktorów nauki jazdy i egzaminatorów prawa jazdy. W opinii instruktorów i egzaminatorów wykonywane przez nich zawody należą do kategorii zawodów zaufania publicznego. W świetle przeprowadzonej analizy nie mają one konstytucyjnych cech pozwalających na uznanie, że w chwili obecnej samorząd zawodowy, o którym mowa w art. 17 ust. 1 Konstytucji RP, stanowi najlepszą formę ich organizacji, czego nie należy wykluczyć w przyszłości, przy spełnieniu określonych warunków.
Zreformowana Anglia w oczach polskich podróżników
Authors: Nortowska Paulina
Published: October 2021

Reformed England in the Eyes of Polish Travelers in the Early Modern Period

The aim of this article is to reconstruct and present the image of reformed England and the English people as perceived by the inhabitants of the Polish-Lithuanian Commonwealth between the sixteenth and eighteenth centuries. The primary source used is travel literature. The author analyses travellers’ impressions with research and educational journeys, “grand tour,” and diplomatic missions related to state or parliamentary activities. Travel literature containing descriptions of England reflect the author’s impressions, feelings, judgments and subjective opinions, as well as convey some knowledge about the world acquired not only during the trip, but also as a result of prior knowledge gained through learning and education. Moreover, the article discusses the emergence of a spectrum of perspectives and prejudices both for and against the English people, as well as the formation of national stereotypes.
The skin: largest organ of the body
Authors: Peate Ian
Published: October 2021

This article concludes this series in the anatomy and physiology of the body systems. An overview of the skin is provided and the various and functions of this, the largest organ of the body, are described. The three layers of the skin are discussed, along with an overview of skin pigmentation.

The skin would be unable to complete most of its functions without the help of its appendages. The subcutaneous glands, hair, nails and nerve endings (the appendages) that allow it to function efficiently are summarised briefly. One other function of the skin—vitamin D synthesis—is described. The article ends with a glossary of terms and a set of questions that are intended to assist with leaning.
Latest clinical news
Authors: Greener Mark
Published: October 2021

Mark Greener rounds up the findings presented at this year's European Respiratory Society Congress
BRD4promotes heterotopic ossification through upregulation of LncRNA MANCR
Authors: Liu Lei , Li ZiHao , Chen Siwen , Cui Haowen , Li Xiang , Dai Guo , Zhong Fangling , Hao Wenjun , Zhang Kuibo , Liu Hui
Published: October 2021

Aims

Acquired heterotopic ossification (HO) is a debilitating disease characterized by abnormal extraskeletal bone formation within soft-tissues after injury. The exact pathogenesis of HO remains unknown. It was reported that BRD4 may contribute to osteoblastic differentiation. The current study aims to determine the role of BRD4 in the pathogenesis of HO and whether it could be a potential target for HO therapy.

Methods

Achilles tendon puncture (ATP) mouse model was performed on ten-week-old male C57BL/6J mice. One week after ATP procedure, the mice were given different treatments (e.g. JQ1, shMancr). Achilles tendon samples were collected five weeks after treatment for RNA-seq and real-time quantitative polymerase chain reaction (RT-qPCR) analysis; the legs were removed for micro-CT imaging and subsequent histology. Human bone marrow mesenchymal stem cells (hBMSCs) were isolated and purified bone marrow collected during surgeries by using density gradient centrifugation. After a series of interventions such as knockdown or overexpressing BRD4, Alizarin red staining, RT-qPCR, and Western Blot (Runx2, alkaline phosphatase (ALP), Osx) were performed on hBMSCs.

Results

Overexpression of BRD4 enhanced while inhibition of Brd4 suppressed the osteogenic differentiation of hBMSCs in vitro. Overexpression of Brd4 increased the expression of mitotically associated long non-coding RNA (Mancr). Downregulation of Mancr suppressed the osteoinductive effect of BRD4. In vivo, inhibition of BRD4 by JQ1 significantly attenuated pathological bone formation in the ATP model (p = 0.001).

Conclusion

BRD4 was found to be upregulated in HO and Brd4-Mancr-Runx2 signalling was involved in the modulation of new bone formation in HO. Cite this article: Bone Joint Res 2021;10(10):668–676.
Development and Validation of an Autonomous Radio-Frequency Identification Controlled Soaking System for Dairy Cattle
Authors: Mazon Gustavo , Montgomery Patrick D , Hayes Morgan , Jackson Joshua , Costa Joao H. C.
Published: October 2021

Highlights

The high variation on how dairy cows experience heat stress opens the space for individual heat abatement options.

We developed an UHF-RFID activated soaking system for dairy cattle and validated it statically and dynamically.

Percentage of soaker activations was moderate when validated statically and very high when validated dynamically.

Future research should validate the system using dairy cows and evaluate effects on physiology and behavior.

Abstract. This study aim was to develop and validate a radio-frequency identification (RFID) controlled cattle soaking system for use in dairy cattle. The autonomous system was composed of a Raspberry Pi microcontroller, an ultra-high frequency (UHF) RFID system, a temperature-humidity sensor, and a water soaker. The system was developed and programmed to identify and tailor heat stress abatement to dairy cattle. The validation of the system was divided into static and dynamic phases. During the static phase, five UHF-RFID tags were statically placed 5 times in 11 points of interest on a ranging from 0 to 150 cm of the antenna. During the dynamic phase, 10 tags were moved 10 times each from 150 cm to the right (closer to the barn) to 150 cm to the left (further from the barn) of the center of the antenna mimicking a cow’s walking speed. During the static validation, the percentage of successful readings was moderate (MEAN±SD; 77.8±30.1%). We found that the distance from the antenna affected the percentage of successful readings (P<0.01), it was 100% up to 60 cm from the antenna and static readings were less successful from 120 cm left up to 90 cm to the right of the center of the antenna. During the dynamic validation, the percentage of successful readings was very high (96.0±7.0%). These results suggest that the autonomous soaker system seems to be able to detect cows in movement underneath the system. Future research should validate the system using live dairy cows. Keywords: Automation, Heat stress, Raspberry Pi, RFID.
Microwave Assisted Convective Air Drying of Sugarloaf Pineapples (Ananas Comosus)
Authors: Abano Ernest Ekow
Published: October 2021

Highlights

Microwave pretreatment before drying reduced drying time significantly.

Microwave-assisted drying increased the effective moisture diffusivity coefficient.

Microwave pretreatment before convective hot-air drying improved quality parameters.

The Middili et al. (2002) model best fitted the microwave-assisted drying of sugarloaf pineapples.

Abstract. This study’s objective was to provide the optimum drying conditions to produce quality dried sugarloaf pineapples using microwave pretreatments before the conventional hot air drying. For this, the effect of microwave power (385 to 697 W), microwave time (2 to 4 min), and air temperature (50°C to 70°C) on the drying kinetics and quality of sugarloaf pineapple were evaluated using the Box Behnken response surface methodology. To reach a 17.44±0.09% kg/kg dry matter moisture content, we found the optimum drying conditions for sugarloaf pineapples to be 697 W microwave power for 2.26 min before convective hot air drying at a temperature of 64.75°C. The predicted drying time, ascorbic acid content, and browning index were 13.68 h, 20.89 mg/100 g, and 0.099 Abs unit at this optimum condition, respectively. The pineapple slices’ effective moisture removal rate pretreated with microwave before drying was higher than the control and was between 6.42 × 10-10 m2/s and 11.82 × 10-10 m2/s while ones without a microwave were between 3.54 × 10-10 m2/s and 8.78 × 10-10 m2/s for drying at air temperature between 50°C and 70°C. It was discovered that the Midilli et al. (2002) model was the most appropriate thin layer model for microwave-assisted drying of sugarloaf pineapples. The pineapple slices’ drying rate potential generally increased with microwave power and pretreatments time but not the corresponding increase in the air temperature. Drying time for microwave-assisted drying was in the range of 11 to 20 h, while the ones without microwaves were between 18 and 24 h. Therefore, microwaves should be considered a pretreatment step to the industrial production of sugarloaf pineapple to reduce drying time and produce better quality products.

Keywords: Drying, Hot air, Microwave, Moisture diffusivity, Sugarloaf pineapple.
Analysis of Influencing Factors on Winter Wheat Yield Estimations Based on a Multisource Remote Sensing Data Fusion
Authors: Li Yan , Ren Yan Zhao , Gao Wan Lin , Tao Sha , Jia Jing Dun , Liu Xin Liang
Published: October 2021

Highlights

The potential of fusing GF-1 WFV and MODIS data by the ESTARFM algorithm was demonstrated.

A better time window selection method for estimating yields was provided.

A better vegetation index suitable for yield estimation based on spatiotemporally fused data was identified.

The effect of the spatial resolution of remote sensing data on yield estimations was visualized.

Abstract. The accurate estimation of crop yields is very important for crop management and food security. Although many methods have been developed based on single remote sensing data sources, advances are still needed to exploit multisource remote sensing data with higher spatial and temporal resolution. More suitable time window selection methods and vegetation indexes, both of which are critical for yield estimations, have not been fully considered. In this article, the Chinese GaoFen-1 Wide Field View (GF-1 WFV) and Terra Moderate Resolution Imaging Spectroradiometer (MODIS) data were fused by the Enhanced Spatial and Temporal Adaptive Reflectance Fusion Model (ESTARFM) to generate time-series data with a high spatial resolution. Then, two time window selection methods involving distinguishing or not distinguishing the growth stages during the monitoring period, and three vegetation indexes, the normalized difference vegetation index (NDVI), two-band enhanced vegetation index (EVI2) and wide dynamic range vegetation index (WDRVI), were intercompared. Furthermore, the yield estimations obtained from two different spatial resolutions of fused data and MODIS data were analyzed. The results indicate that taking the growth stage as the time window unit division basis can allow a better estimation of winter wheat yield; and that WDRVI is more suitable for yield estimations than NDVI or EVI2. This study demonstrates that the spatial resolution has a great influence on yield estimations; further, this study identifies a better time window selection method and vegetation index for improving the accuracy of yield estimations based on a multisource remote sensing data fusion. Keywords: Remote sensing, Spatiotemporal data fusion, Winter wheat, Yield estimation.
A General Purpose Laboratory for Small-Scale In-Barn Swine Discoveries
Authors: Weyer Sara E. , Smith Benjamin C. , Ramirez Brett C. , Harmon Jay D. , Anderson Daniel S.
Published: October 2021

Highlights

Design and construction of mobile swine facility on a flat decked trailer for experimentation.

Air infiltration evaluation for an experimental building.

Theoretical building shell thermal analysis and heat transfer determination.

Abstract. Specialized animal environment experiments needing swine facilities calls for novel technology creation to enable unique experimentation without the drawbacks of traditional swine facilities. In a full-scale swine facility, there are challenges with cost, increased travel time to sites, additional labor is required, the facility cannot be fully controlled, and biosecurity becomes a risk. A small-scale, mobile swine confinement laboratory was designed and built to mitigate the challenges faced in a full-scale barn. The mobility of the laboratory enables it to travel to swine farms to obtain fresh animal specimens, which allows the experiments and data collected to be more representative of an in-barn application. The model facility, built on a flat-bed trailer, has two identical, fully instrumented rooms (L × W × H) of 2.24 × 2.29 × 2.05 m (88.0 × 90.0 × 80.5 in.) with a 0.46 m (18 in.) shallow pit, replicating typical swine finishing rooms. Walls were composed of typical wood-frame construction with interior paneling and metal clad on the exterior. Instrumentation allows the environment and air quality of the rooms, along with other parameters, to be controlled and monitored. The rear portion of the trailer includes an instrumentation room to house necessary computers, controllers, and associated equipment. Commissioning of components and verifying function of equipment were performed, which included quantifying infiltration and performing a thermal analysis for each room. Analysis showed that the infiltration equation was distinct for each room. The use of this laboratory for qualitative and quantitative evaluation of in-barn experimentation on a controlled, small-scale will mitigate the challenges presented in a typical barn. Keywords: Building, Commissioning, Facility, Heat transfer, Mobile, Pig.
Pig Face Recognition Model Based on a Cascaded Network
Authors: Wang Rong , Shi ZaiFeng , Li Qifeng , Gao Ronghua , Zhao Chunjiang , Feng Lu
Published: October 2021

Highlights

A pig face recognition model that cascades the pig face detection network and pig face recognition network is proposed.

The pig face detection network can automatically extract pig face images to reduce the influence of the background.

The proposed cascaded model reaches accuracies of 99.38%, 98.96% and 97.66% on the three datasets.

An application is developed to automatically recognize individual pigs.

Abstract. The identification and tracking of livestock using artificial intelligence technology have been a research hotspot in recent years. Automatic individual recognition is the key to realizing intelligent feeding. Although RFID can achieve identification tasks, it is expensive and easily fails. In this article, a pig face recognition model that cascades a pig face detection network and a pig face recognition network is proposed. First, the pig face detection network is utilized to crop the pig face images from videos and eliminate the complex background of the pig shed. Second, batch normalization, dropout, skip connection, and residual modules are exploited to design a pig face recognition network for individual identification. Finally, the cascaded network model based on the pig face detection and recognition network is deployed on a GPU server, and an application is developed to automatically recognize individual pigs. Additionally, class activation maps generated by grad-CAM are used to analyze the performance of features of pig faces learned by the model. Under free and unconstrained conditions, 46 pigs are selected to make a positive pig face dataset, original multiangle pig face dataset and enhanced multiangle pig face dataset to verify the pig face recognition cascaded model. The proposed cascaded model reaches accuracies of 99.38%, 98.96%, and 97.66% on the three datasets, which are higher than those of other pig face recognition models. The results of this study improved the recognition performance of pig faces under multiangle and multi-environment conditions. Keywords: CNN, Deep learning, Pig face detection, Pig face recognition.
Plant Leaf Segmentation and Phenotypic Analysis Based on Fully Convolutional Neural Network
Authors: Cao Liying , Li Hongda , Yu Helong , Chen Guifen , Wang Heshu
Published: October 2021

Highlights

Modify the U-Net segmentation network to reduce the loss of segmentation accuracy.

Reducing the number of layers U-net network, modifying the loss function, and the increase in the output layer dropout.

It can be well extracted after splitting blade morphological model and color feature.

Abstract. From the perspective of computer vision, the shortcut to extract phenotypic information from a single crop in the field is image segmentation. Plant segmentation is affected by the background environment and illumination. Using deep learning technology to combine depth maps with multi-view images can achieve high-throughput image processing. This article proposes an improved U-Net segmentation network, based on small sample data enhancement, and reconstructs the U-Net model by optimizing the model framework, activation function and loss function. It is used to realize automatic segmentation of plant leaf images and extract relevant feature parameters. Experimental results show that the improved model can provide reliable segmentation results under different leaf sizes, different lighting conditions, different backgrounds, and different plant leaves. The pixel-by-pixel segmentation accuracy reaches 0.94. Compared with traditional methods, this network achieves robust and high-throughput image segmentation. This method is expected to provide key technical support and practical tools for top-view image processing, Unmanned Aerial Vehicle phenotype extraction, and phenotype field platforms. Keywords: Deep learning, Full convolution neural network, Image segmentation, Phenotype analysis, U-Net.
Rapid Recognition of Tomato’s Disease Stages Based on the Kernel Mutual Subspace Method
Authors: Zhang Yan , Wu Huarui , Wang Xiaomin
Published: October 2021

Highlights

A low time complexity and high accuracy recognition method of tomato’s disease stages was proposed.

Small number of disease image samples can support a stable and high accuracy method with less computation time and less memory cost.

Provided a solution to establish a real-time and low energy consumption disease recognize system.

Abstract. Disease stages recognition of tomato is important for the timely diagnosis and prevention of tomato diseases. In this article, the color and texture features were extracted, and the kernel mutual subspace method (KMSM) was introduced to establish a rapid Tomato’s disease stage recognition method. Firstly, the color and textural features were extracted from tomato leaf and mapped to a high-dimensional space using a Gaussian kernel function. Secondly, a nonlinear disease feature subspace was established by applying principal component analysis (PCA) based on the mapped high-dimensional space. Finally, disease stages are recognized by calculating the canonical angles between the testing subspace and reference sub-spaces. To validate recognition rate of the proposed method, we conducted 10-fold cross-validation for experiments using the tomato disease sets contained in PlantVillage and artificial intelligence (AI) Challenger 2018 datasets. Also compared with the support vector machine (SVM) and VGG 16 methods, the results show that, accuracy of those three evaluated methods on the PlantVillage datasets are 99.34%, 89.2%, and 97%, respectively; and accuracy on the AI Challenger 2018 datasets are 98.66%, 71.14%, and 73.93%, respectively. Moreover, average training and recognition time of the proposed method is 0.1496 and 0.008 s, respectively, which is faster than SVM and VGG16 methods. In conclusion, the proposed method can be carried out in real-time recognition intelligent equipment which requires less memory space, less computation time, and with higher recognition rate, and low energy consumption. Keywords: Color and textural feature, High dimensional feature space, Kernel mutual subspace method, Tomato’s disease stages recognition,.
Research and Experiment on Path-Tracking Control of Autonomous Tractor Based on Lateral Deviation and Yaw Rate Feedback
Authors: Zhang Bingli , Cheng Jin , Zheng Pingping , Li Aojia , Cheng Xiaoyu
Published: October 2021

Highlights

Automatic navigation technology in autonomous tractors is one of the key technologies in precision agriculture.

A path-tracking control algorithm based on lateral deviation and yaw rate feedback is proposed.

The modified steering angle was obtained by comparing the ideal yaw rate with the actual yaw rate.

The results demonstrate the efficiency and superior accuracy of the proposed algorithm for tractor path-tracking control.

Abstract. The performance of path-tracking control systems for autonomous tractors affects the quality and efficiency of farmland operations. The objective of this study was to develop a path-tracking control algorithm based on lateral deviation and yaw rate feedback. The autonomous tractor path lateral dynamics model was developed based on preview theory and a two-degree-of-freedom tractor model. According to the established dynamic model, a path-tracking control algorithm using yaw angular velocity correction was designed, and the ideal steering angle was obtained by lateral deviation and sliding mode control. The modified steering angle was obtained by a proportional-integral-derivative feedback controller after comparing the ideal yaw rate with the actual yaw rate, which was then combined with the ideal steering angle to obtain the desired steering angle. The simulation and experimental results demonstrate the efficiency and superior accuracy of the proposed tractor path-tracking control algorithm, enabling its application in automatic navigation control systems for autonomous tractors. Keywords: Autonomous tractor, Path-tracking control, Sliding mode control, Yaw rate feedback.
Effects of Various Edge-Curve Types and Rotational Speeds of Disc Blades on Breaking Force and Energy Consumption in the Maize Stalk Chopping Process
Authors: Liu Peng , He Jin , Li Hongwen , Wang Qingjie , Lu Caiyun , Lou Shangyi , Wang Yingbo , Lin Han , Li Hui , Zhang Zhenguo
Published: October 2021

Highlights

The peak breaking force and energy consumption change in maize stalk were predicted by the FEM.

A high SADBT reduced the PBFR and PBFS and increased the ECSC.

The TRYDB had the most critical effect on the peak breaking force and energy consumption.

Abstract. The mechanized retention of stalks is the primary method to avoid open burning. However, the variation in the breaking force and energy consumption in the chopping process of mechanized retention must be clarified. Therefore, based on the finite element method (FEM) and field validation experiments, the effects of various edge-curve types and rotational speeds of disc blades for maize stalk retention on the breaking force and energy consumption were examined. The test indices were the peak breaking force of the rind (PBFR) and stalk (PBFS), energy consumption of stalk chopping (ECSC), and energy transmission efficiency (ETE). The test factors were the spiral disc blade type (Archimedean, logarithmic, and sinusoidal-exponential spiral), slide-cutting angles of the disc blade tip (SADBT, 30°, 40°, 50°, and 60°), rotational speed of the Y-type blade (RSYB, 1400, 1600, 1800, 2000, 2200, and 2400 rpm), and transmission ratio between Y-type and disc blades (TRYDB, 0.25, 0.50, 0.75, and 1.0). The chopping process was divided into the cutting processes of the initial rind, rind and pith, final rind, and stalk end. The results showed that the SADBT, TRYDB, and RSYB had significant effects on the PBFR, PBFS, ECSC, and ETE. The most influential factor on all test indices was the TRYDB. The RSYB positively affected the PBFR, PBFS, and ECSC. The growth rates of the PBFR, PBFS, and ECSC increased with the TRYDB. The maximum PBFR, PBFS, and ETE values were obtained under an SADBT of 60°, and the maximum ECSC value was obtained under an SADBT of 40°. The difference in energy consumption between the field validation experiment and simulation was less than 10%, which proved the correct results of the FEM simulation. Keywords: Energy consumption, Finite element method, Maize stalk, Peak breaking force, Slide cutting.
A Precision Agriculture Technology Course for Regions with Lower Technology Adoption Levels
Authors: Mathanker Sunil
Published: October 2021

Highlights

Prior and post-knowledge surveys showed that students had varied knowledge levels in the course topics.

Knowledge gains were higher for the course topics with lower prior knowledge scores.

Knowledge surveys can be used to adapt to the needs of the students in real-time, improve instructional material, identify effective teaching methods, and modify the course.

Abstract. Precision agriculture technologies offer several benefits, and most important among them are higher farm profits and improved environmental health. The quality of precision agriculture education is one of the main barriers to the adoption of these technologies. There are studies documenting the development of precision agriculture technology courses for the world regions with higher levels of adoption. However, there are limited studies for the world regions typically characterized by lower adoption of these technologies. This study attempts to develop and teach a precision agriculture technology course for such a world region Puerto Rico, a U.S. territory. This study also consisted of collecting and analyzing the pre- and post-knowledge levels of the students attending the developed course. Using the procedure for calculation of overall grade point average, the knowledge score for each course topic was calculated from all the pre- or post-survey responses for the course topic. Additionally, the knowledge gain for each course topic was calculated by subtracting the prior knowledge score from the post knowledge score of the course topic. The results indicated that knowledge gains were higher for the course topics with the lower prior knowledge scores and were lower for the course topics with the higher prior knowledge scores. The study indicates that a prior knowledge survey can be used to adapt to the needs of the students in real-time. Likewise, a post-knowledge survey can be used to improve instructional material, identify suitable teaching methods, and modify the course. World regions with limited adoption of precision agriculture technology may begin with a precision agriculture technology course without laboratory exercises, and later add laboratory exercises as equipment becomes available and adoption level increases. Keywords: Agricultural and environmental systems, Course development, Curriculum, Precision agriculture technologies, Student assessment
Surface solution to correct a freeform wavefront
Authors: González-Acuña Rafael G.
Published: October 2021

In this paper an equation is presented to
design a refractive surface such that, given an arbitrary wavefront,
the surface refracts it into a perfect spherical wave. The equation
that computes these refractive surfaces is exhaustively tested using
ray-tracing techniques, and the performance is as expected.
Computer-generated hologram manipulation and fast production with a focus on security application
Authors: Cviljušac Vladimir , Brkić Antun Lovro , Sviličić Blaž , Čačić Marko
Published: October 2021

Motivated by the successful printing of a computer-generated hologram
using the computer-to-film (CtF) graphic process, we present a further
refined technique with increased resolution, applicable in security.
The CtF process offers low cost and fast production while persevering
high resolution, and it can make every hologram unique. In this paper,
we present the improvement of the printing method, with several
software modifications and the implementation of security features at
different levels of production.
Etched fiber Bragg grating probe using a regular CNC machine and a 3D printer
Authors: Oliveira Vicente A. , Carneiro Alexander C. , Dos Santos Alexandre B. , Barbero Andrés Pablo L. , Peixoto Fernando C. , Silva Vinicius N. H.
Published: October 2021

Etched fiber Bragg gratings (EFBGs) have been widely employed for refractive index (RI) measurements that can be used to monitor sugar consumption during the fermentation of alcoholic beverages. EFBGs are obtained by removing the cladding of a fiber Bragg grating, which is traditionally performed by a chemical attack with hydrogen fluoride, an extremely hazardous corrosive substance that causes severe wounds and even death. To overcome such drawbacks, this technical note presents a simple, practical, and low cost method for the diameter reduction of single mode optical fibers by mechanical polishing, employing a small scale computer numerical control device and an ad hoc 3D-printed rod. The sensor probe obtained was tested using sucrose aqueous solutions with RIs between 1.333 and 1.394, measured in an Abbe refractometer. The results show a linear shift of the Bragg wavelength with respect to RI with a correlation of 0.928.
Broadband terahertz metamaterial absorber: design and fabrication
Authors: Qiu Yanqing , Wang Jinfeng , Xiao Meiyu , Lang Tingting
Published: October 2021

We proposed and experimentally demonstrated a broadband terahertz (THz) metamaterial absorber based on a symmetrical L-shaped metallic resonator. The absorber structure produces two absorption peaks at 0.491 and 0.73 THz, with the absorption rates of 98.6% and 99.6%, respectively. Broadband absorption was obtained from 0.457 to 1 THz, achieving a 

>

90

%

absorption bandwidth of 0.543 THz. By analyzing the distributions of the electric and magnetic field at the two resonance frequencies, electric and magnetic dipole resonances were proposed to explain the broadband absorption mechanism. Furthermore, various widths and lengths of the symmetrical L-shaped metallic resonator on the absorption characteristics were investigated. Moreover, the broadband absorption characteristic can be maintained with an incident angle of up to 45° for transverse-electric and 30° for transverse-magnetic polarization. Finally, we experimentally observed a 

>

70

%

broadband absorption characteristic from 0.42 to 1 THz. This proposed absorber has the potential for bolometric imaging, modulating, and spectroscopy in the THz region.
Automated phase unwrapping in digital holography with deep learning
Authors: Park Seonghwan , Kim Youhyun , Moon Inkyu
Published: October 2021

Digital holography can provide quantitative phase images related to the morphology and content of biological samples. After the numerical image reconstruction, the phase values are limited between −π and π; thus, discontinuity may occur due to the modulo 2π operation. We propose a new deep learning model that can automatically reconstruct unwrapped focused-phase images by combining digital holography and a Pix2Pix generative adversarial network (GAN) for image-to-image translation. Compared with numerical phase unwrapping methods, the proposed GAN model overcomes the difficulty of accurate phase unwrapping due to abrupt phase changes and can perform phase unwrapping at a twice faster rate. We show that the proposed model can generalize well to different types of cell images and has high performance compared to recent U-net models. The proposed method can be useful in observing the morphology and movement of biological cells in real-time applications.
Forward terahertz wave generation from liquid gallium in the non-relativistic regime
Authors: Garriga Francis Kareem , Cao Yuqi , E Yiwen , Ling Fang , Lim Pac Chong Mervin , Zhang Xi-Cheng
Published: October 2021

We characterize a terahertz (THz) source based on plasma in liquid gallium. The dependence of the emitted THz pulse energy on second-order phase, pump pulse energy, and polarization of the short laser pulse is demonstrated. Our study suggests that the THz emission mechanism is due to the ponderomotive force and is aided by a direct-field driven term. The proposed source and accompanying generation mechanism are studied under a non-relativistic regime (

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0

18

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) for forward directed THz under a single pump excitation scheme.
Space-time vector light sheets
Authors: Diouf Mbaye , Harling Mitchell , Yessenov Murat , Hall Layton A. , Abouraddy Ayman F. , Toussaint Kimani C.
Published: October 2021

We introduce the space-time (ST) vector light sheet. This unique one-dimensional ST wave packet is characterized by classical entanglement (CE), a correlation between at least two non-separable intrinsic degrees-of-freedom (DoFs), which in this case are the spatiotemporal DoFs in parallel with the spatial-polarization DoFs. We experimentally confirm that the ST vector light sheet maintains the intrinsic features of the uniformly polarized ST light sheet, such as near-diffraction-free propagation and self-healing, while also maintaining the intrinsic polarization structure of common vector beams, such as those that are radially polarized and azimuthally polarized. We also show that the vector beam structure of the ST vector light sheet is maintained in the subluminal and superluminal regimes.
Micro to macro scale simulation coupling for stray light analysis
Authors: Crocherie Axel , Pond James , Gomez Federico Duque , Channon Kevin , Fantoni Frederic
Published: October 2021

Stray light in an optical system is unwanted parasitic light that may degrade performance. It can originate from different sources and may lead to different problems in the optical system such as fogging, ghost images for imagers, or inaccurate measurements for time of flight applications. One of the root causes is the reflectivity of the sensor itself. In this paper we present a new optical simulation methodology to analyze the stray light contribution due to the sensor reflectivity by coupling electromagnetic simulation (to calculate the pixels’ bidirectional reflectance distribution function, also named BRDF) and ray-tracing simulation (for stray light analysis of the camera module). With this simulation flow we have been able to reproduce qualitatively red ghost images observed on different sensors in our laboratory.
Channel-multiplexing for quasi-distributed acoustic sensing with orthogonal codes
Authors: Jiang Jialin , Deng Ziwen , Wang Zinan
Published: October 2021

With the increasing demands for large-scale acoustic sensing in many important fields such as hydrophone, vehicle tracking and pipeline monitoring, optical fiber-based distributed acoustic sensing (DAS) has experienced a rapid development. In recent years, quasi-distributed acoustic sensing (QDAS) based on single mode fiber with enhanced point array has emerged, which is a good approach to improve signal-to-noise ratio and deal with the interference-fading problem in DAS. However, similar to DAS, the performance of QDAS is also limited by the finite frequency domain resources. To break the trade-off between sensing bandwidth and distance, additional frequency domain resources are always needed to multiplex the sensing channel. Multiple-input multiple-output coding technology is an approach to realize QDAS channel-multiplexing with the orthogonal probe waves in the same frequency band. In this paper, the iteration constrain condition of the orthogonal codes is modified, and the generation method of more orthogonal codes with high and consistent suppression ratio for QDAS is provided. In the demonstration experiment, the QDAS has successfully achieved 5 times the sensing bandwidth expansion on a 5.19 km fiber based on 5 new orthogonal codes on the same frequency, with 5 m spatial resolution and 10

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strain noise level.
Femtosecond nearly resonant self-focusing in gold nanorod colloids
Authors: Agiotis Leonidas , Meunier Michel
Published: October 2021

We evaluate the threshold power for self-focusing in gold nanorod colloids of varying concentration by a power limiting method in the femtosecond filamentation regime. The pulses are tuned near the longitudinal plasmon peak of the nanorods, leading to saturation of linear absorption and reshaping of the particles. We evaluated the last two effects by optical transmission measurements and spectroscopic analysis and estimated that considerable particle deformation does not occur before the collapse of the beam. We performed numerical simulations based on the experimental results, and evaluated only a subtle, monotonically increasing enhancement of the nonlinear refractive index of the host material (water) as the nanoparticles concentration increases. The role of higher-order contributions is discussed. Our work provides an alternative characterization approach of ultrafast nonlinearities in absorbing media. It further emphasizes that self-focusing of intense femtosecond pulses in gold nanocomposites is hampered by the ultrafast modulation of the susceptibility of the metal.
Etch-free additive lithographic fabrication methods for reflective and transmissive micro-optics
Authors: Fu Qiang , Amata Hadi , Heidrich Wolfgang
Published: October 2021

With the widespread application of micro-optics in a large range of areas, versatile high quality fabrication methods for diffractive optical elements (DOEs) have always been desired by both the research community and by industry. Traditionally, multi-level DOEs are fabricated by a repetitive combination of photolithography and reactive-ion etching (RIE). The optical phase accuracy and micro-surface quality are severely affected by various etching artifacts, e.g., RIE lag, aspect ratio dependent etching rates, and etching artifacts in the RIE steps. Here we propose an alternative way to fabricate DOEs by additively growing multi-level microstructures onto the substrate. Depth accuracy, surface roughness, uniformity and smoothness are easily controlled to high accuracy by a combination of deposition and lift-off, rather than etching. Uniform depths can be realized for both micrometer and millimeter scale features that are simultaneously present in the designs. The grown media can either be used directly as a reflective DOE, or as a master stamp for nanoimprinting refractive designs. We demonstrate the effectiveness of the fabrication methods with representative reflective and transmissive DOEs for imaging and display applications.