PolyFit: A Peg-in-hole Assembly Framework for Unseen Polygon Shapes via Sim-to-real Adaptation

The study addresses the foundational and challenging task of peg-in-hole assembly in robotics, where misalignments caused by sensor inaccuracies and mechanical errors often result in insertion failures or jamming. This research introduces PolyFit, representing a paradigm shift by transitioning from a reinforcement learning approach to a supervised learning methodology. PolyFit is a Force/Torque (F/T)-based supervised learning framework designed for 5-DoF peg-in-hole assembly. It utilizes F/T data for accurate extrinsic pose estimation and adjusts the peg pose to rectify misalignments. Extensive training in a simulated environment involves a dataset encompassing a diverse range of peg-hole shapes, extrinsic poses, and their corresponding contact F/T readings. To enhance extrinsic pose estimation, a multi-point contact strategy is integrated into the model input, recognizing that identical F/T readings can indicate different poses. The study proposes a sim-to-real adaptation method for real-world application, using a sim-real paired dataset to enable effective generalization to complex and unseen polygon shapes. PolyFit achieves impressive peg-in-hole success rates of 97.3% and 96.3% for seen and unseen shapes in simulations, respectively. Real-world evaluations further demonstrate substantial success rates of 86.7% and 85.0%, highlighting the robustness and adaptability of the proposed method.Comment: 8 pages, 8 figures, 3 table

INSTA-BEEER: Explicit Error Estimation and Refinement for Fast and Accurate Unseen Object Instance Segmentation

Efficient and accurate segmentation of unseen objects is crucial for robotic manipulation. However, it remains challenging due to over- or under-segmentation. Although existing refinement methods can enhance the segmentation quality, they fix only minor boundary errors or are not sufficiently fast. In this work, we propose INSTAnce Boundary Explicit Error Estimation and Refinement (INSTA-BEEER), a novel refinement model that allows for adding and deleting instances and sharpening boundaries. Leveraging an error-estimation-then-refinement scheme, the model first estimates the pixel-wise boundary explicit errors: true positive, true negative, false positive, and false negative pixels of the instance boundary in the initial segmentation. It then refines the initial segmentation using these error estimates as guidance. Experiments show that the proposed model significantly enhances segmentation, achieving state-of-the-art performance. Furthermore, with a fast runtime (less than 0.1 s), the model consistently improves performance across various initial segmentation methods, making it highly suitable for practical robotic applications.Comment: 8 pages, 5 figure

The Development of Transparent Photovoltaics

Transparent photovoltaics (TPVs), which combine visible transparency and solar energy conversion, are being developed for applications in which conventional opaque solar cells are unlikely to be feasible, such as windows of buildings or vehicles. In this paper, we review recent progress in TPVs along with strategies that enable the transparency of conventional photovoltaics, including thin-film technology, selective light-transmission technology, and luminescent solar concentrator technology. From fundamental research to commercialization of the TPV, three main perspectives should be considered: (1) high-power conversion efficiency at the same average visible transmittance; (2) aesthetic factors, which should not detract from applications such as buildings and vehicles; and (3) feasibility for real-world applications, including modularization and stability evaluation. We present the distinct analysis criteria for these main perspectives and discuss their importance. We also discuss possible research directions for the commercialization of TPVs

Effects of NaOH Activation on Adsorptive Removal of Herbicides by Biochars Prepared from Ground Coffee Residues

In this study, the adsorption of herbicides using ground coffee residue biochars without (GCRB) and with NaOH activation (GCRB-N) was compared to provide deeper insights into their adsorption behaviors and mechanisms. The physicochemical characteristics of GCRB and GCRB-N were analyzed using Brunauer-Emmett-Teller surface area, Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction and the effects of pH, temperature, ionic strength, and humic acids on the adsorption of herbicides were identified. Moreover, the adsorption kinetics and isotherms were studied. The specific surface area and total pore volume of GCRB-N (405.33 m(2)/g and 0.293 cm(3)/g) were greater than those of GCRB (3.83 m(2)/g and 0.014 cm(3)/g). The GCBR-N could more effectively remove the herbicides (Q(e,exp) of Alachlor = 122.71 mu mol/g, Q(e,exp) of Diuron = 166.42 mu mol/g, and Q(e,exp) of Simazine = 99.16 mu mol/g) than GCRB (Q(e,exp) of Alachlor = 11.74 mu mol/g, Q(e,exp) of Diuron = 9.95 mu mol/g, and Q(e,exp) of Simazine = 6.53 mu mol/g). These results suggested that chemical activation with NaOH might be a promising option to make the GCRB more practical and effective for removing herbicides in the aqueous solutions

Application of airborne hyperspectral imagery to retrieve spatiotemporal CDOM distribution using machine learning in a reservoir

Colored dissolved organic matter (CDOM) in inland waters is used as a proxy to estimate dissolved organic carbon (DOC) and may be a key indicator of water quality and nutrient enrichment. CDOM is optically active fraction of DOC so that remote sensing techniques can remotely monitor CDOM with wide spatial coverage. However, to effectively retrieve CDOM using optical algorithms, it may be critical to select the absorption co-efficient at an appropriate wavelength as an output variable and to optimize input reflectance wavelengths. In this study, we constructed a CDOM retrieval model using airborne hyperspectral reflectance data and a machine learning model such as random forest. We evaluated the best combination of input wavelength bands and the CDOM absorption coefficient at various wavelengths. Seven sampling events for airborne hyperspectral imagery and CDOM absorption coefficient data from 350 nm to 440 nm over two years (2016-2017) were used, and the collected data helped train and validate the random forest model in a freshwater reservoir. An absorption co-efficient of 355 nm was selected to best represent the CDOM concentration. The random forest exhibited the best performance for CDOM estimation with an R2 of 0.85, Nash-Sutcliffe efficiency of 0.77, and percent bias of 3.88, by using a combination of three reflectance bands: 475, 497, and 660 nm. The results show that our model can be utilized to construct a CDOM retrieving algorithm and evaluate its spatiotemporal variation across a reservoir

Primary brain T-cell lymphoma of the lymphoblastic type presenting as altered mental status

The authors present a case of a 56-year-old man with altered mental status. Magnetic resonance imaging (MRI) of the brain revealed non-enhancing abnormalities on T2 and FLAIR imaging in the brainstem, cerebellum, and cerebrum. Immunohistochemisty demonstrated precursor T-cell lymphoblastic lymphoma. After treatment with methotrexate, he improved clinically without focal sensorimotor deficits and with improving orientation. MRI showed almost complete resolution of brainstem and cerebral lesions. To the authors’ knowledge, there are only five previous reports of primary central nervous system T-cell lymphoblastic lymphoma. Since treatable, it deserves consideration in patients with altered mental status and imaging abnormalities that include diffuse, non-enhancing changes with increased signal on T2-weighted images

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School of Energy and Chemical Engineering (Energy Engineering)Solar cells have attracted considerable attention as an emission-free, eco-friendly alternative energy source owing to an impending global environmental and energy crisis. However, commercialized solar cells have limited applicability because they are rigid and opaque. Hence, research on solar cells with added functionalities, such as flexible and transparent solar cells, are actively being conducted. Transparent solar cells are novel devices that combine solar energy conversion and visible transparency. Transparent solar cells are gaining more popularity as they are applicable in various areas, including building-integrated photovoltaics and glass for vehicles. Up to now, transparent solar cells are developed mainly focusing on organic solar cells and dye-sensitized solar cells. Most of the polymers and dyes used in organic solar cells and dye-sensitized solar cells can be fabricated to thin-film easily via a solution process such as spin coating. And, the thin film has light transparency. Therefore, many studies are being conducted on transparent solar cells based on thin films utilizing this property. However, solar cells based on organic materials still have challenging problems such as low stability in moisture and other environmental conditions. Furthermore, they have shown specific hue because the polymers or dyes have their color. Crystalline silicon solar cells have high power conversion efficiency (up to 26.7%) and high stability (lifetime over 20 years) compared to other types of solar cells, and the materials required for fabricating them are also abundant (silicon is the second abundant material in Earth). Therefore, crystalline silicon solar cells currently occupy more than 90% of the solar cell market. Despite the advantages of the crystalline silicon solar cells, the opaque nature of the crystalline silicon wafer, which is a primary material of crystalline silicon solar cells, makes the development of transparent solar cells using crystalline silicon challenging. Firstly, in this thesis, I will explain the development of transparent crystalline silicon substrate, which is the basic material to develop the crystalline silicon solar cells. Transparent crystalline silicon substrate was developed by establishing micro-sized light transmission windows to a 200-??m thick crystalline silicon wafer known to be opaque. The windows were formed to enable the penetration of visible range. Therefore, the substrate shows a neutral color. Furthermore, the gap between the light transmission windows was chosen using the minimum angle of resolution. Therefore, in the case of the human, each light transmission windows are invisible. Light absorption regions were formed on the transparent crystalline silicon substrate to absorb incident light efficiently. Secondly, I will discuss how to fabricate crystalline silicon-based transparent solar cells using the developed colorless glass-like silicon substrate. The photovoltaic performance of the transparent crystalline silicon solar cells is much higher than that of other types reported colorless transparent solar cells until now. Thus, the developed transparent crystalline silicon solar cells are the best choice for the development of the emerging transparent solar cells that will satisfy high power conversion efficiency as well as high stability and neutral colors such as glass. Furthermore, we believe that the research results of this thesis would contribute to developing next-generation solar cells, especially transparent solar cells. In addition, this study makes an important contribution to the fields of solar cells as well as other transparent electronics.clos

Intraoperative use of fibrin glue in blepharoplasty: a possible solution to reduce postoperative complication

Abstract The purpose of this study was to investigate the effects of intraoperative fibrin glue use on surgery for blepharoptosis. This retrospective study included patients with acquired blepharoptosis who underwent surgical correction and were followed for at least one month. Patients were classified into two groups depending on whether treated with antithrombotic agents or otherwise. All patients taking antithrombotic agents discontinued with the treatment one week prior to surgery in accordance with our clinical guidelines. Preoperative and postoperative marginal reflex distance 1(MRD1) and ecchymosis grade were evaluated and compared. The subjects were 56 patients (111 eyes) who discontinued antithrombotic agents before surgery and 59 patients (117 eyes) who had never taken antithrombotic agents. Fibrin glue was used in 13 patients (26 eyes, 23.4%) in the antithrombotic group, and 11 patients (21 eyes, 17.9%) in the non-antithrombotic group. The rate of severe ecchymosis was significantly lower in patients who used fibrin glue in the antithrombotic group at 1 week (11.5 vs 40.0%, p = 0.008). However, in non-antithrombotic group, there was no difference in the rate of severe ecchymosis according to the use of fibrin glue at 1 week (14.3 vs 30.2%, p = 0.181). In patients with a history of taking antithrombotic agents, the intraoperative use of fibrin glue is thought to be helpful as it could significantly reduce significant ecchymosis