603 research outputs found
Learning 3D Part Assembly from a Single Image
No full textAutonomous assembly is a crucial capability for robots in many applications. For this task, several problems such as obstacle avoidance, motion planning, and actuator control have been extensively studied in robotics. However, when it comes to task specification, the space of possibilities remains underexplored. Towards this end, we introduce a novel problem, single-image-guided 3D part assembly, along with a learning-based solution. We study this problem in the setting of furniture assembly from a given complete set of parts and a single image depicting the entire assembled object. Multiple challenges exist in this setting, including handling ambiguity among parts (e.g., slats in a chair back and leg stretchers) and 3D pose prediction for parts and part subassemblies, whether visible or occluded. We address these issues by proposing a two-module pipeline that leverages strong 2D-3D correspondences and assembly-oriented graph message-passing to infer part relationships. In experiments with a PartNet-based synthetic benchmark, we demonstrate the effectiveness of our framework as compared with three baseline approaches (code and data available at https://github.com/AntheaLi/3DPartAssembly)
Design of high frequency ultrasonic array transducers for medical imaging
No full textUltrasonic transducers have been widely used in the medical applications. High frequency array transducers have recently attracted many research interests, since it provides not only the electronic beamforming but also the very fine image resolution. The transducers are usually either annular or linear arrays. This study concentrates on the design of both types of array in high frequency applications.The annular array is firstly investigated, and an optimized design of array geometry is developed including the kerfs influence which is usually neglected in the design of high frequency arrays. The improved imaging performance is found by this optimized design. More interestingly, the conventional annular array with element having the same surface area has a relatively large sidelobe closest to the main lobe. Two methods are applied to suppress the sidelobe. The method of using high-impedance single matching to enlarge the element bandwidth only shows very limited lobe suppression, however, a novel matching approach is found. Another method of changing the array geometry from equal area elements to equal width ones successfully suppressed the sidelobe. The imaging results suggest that the novel equal width array shows a good improvement.The linear array is then analyzed. The kerfs influence again is found to be significant for the array especially for high frequency. It is essential to use a high attenuated kerfs material in the linear array design. More importantly, the limitation of current fabrication techniques forces the linear array to concede a high grating lobe in the imaging field if it operates in a relatively high frequency. A novel linear array is developed to suppress the grating lobe without using advanced fabrication techniques. The imaging results show that the novel linear array has a general reduction of -6dB for the lobe suppression. The novel design made the linear array operate in a very high frequency without strong grating lobe, and the array can be fabricated by current techniques
The CO2 adsorption on modified ordered mesoporous carbon
No full text本研究以水熱法合成高比表面積之規則中孔洞碳材（OMC），以硝酸氧化修飾中孔洞碳材（OMCA），增加含氧之官能基，之後以迴流嫁接法接合不同胺基批覆量（5、10及20 wt%）及不同種類之胺基分子（四乙烯戊胺，Tetraethylenepentamine，TEPA；三（2-胺基乙基）胺，Tris（2-aminoethyl）amine，TAEA；聚乙烯亞胺，Polyethylenimine，PEI）進行胺基修飾。利用X光粉末繞射儀（XRD）、氮氣等溫吸附-脫附儀（BET）、場發射式掃描電子顯微鏡（FESEM）及穿透式電子顯微鏡（TEM）鑑定所製備的中孔洞碳材之結構及外觀形貌，以傅立葉轉換紅外光譜儀（FTIR）及元素分析儀（EA）探討材料之表面官能基及元素含量，並鑑定胺基修飾材料之表面接合胺基量及孔徑大小差異。在二氧化碳吸附測定方面，利用重量法及體積法評估材料的二氧化碳吸附量，並計算出胺基之氮原子利用效率（CO2/N ratio）。最後利用原位紅外光譜儀（In-situ FTIR）判斷二氧化碳吸附後之產物，以解釋反應機制。 實驗結果顯示，在TEPA及TAEA方面，10 wt%為最適批覆量，而OMCA- TEPA-10有最高之吸附量，多於OMCA-TAEA-10及OMCA-PEI-10。體積法之結果顯示，OMCA-TEPA-10有最高之化學吸附量，13.23 μg/m2，多於OMCA-TAEA-10之12.96 μg/m2，及OMCA-PEI-10之7.03 μg/m2。然而在氮原子利用效率上，OMCA-TEPA-10卻為最低值0.027，低於OMCA-TAEA-10之0.037及OMCA-PEI-10之0.031，此因TEPA之長直鏈分子的立體障礙所導致。在原位紅外光譜儀的結果，則發現三種胺基有carbamic acid及carbamate的共同吸附產物，且吸附產物在不同溫度下的訊號強弱變化趨勢與化學吸附量之變化趨勢相同。1In this study, the ordered mesoporous carbon (OMC) with high surface areas and high pore volume was prepared by hydrothermal method, and then modified by nitric acid solution, which was named OMCA. OMCA materials were modified by grafting different amine separately, which were tetraethylenepentamine (TEPA) , tris（2-aminoethyl）amine (TAEA) and polyethylenimine (PEI), and loaded with varied amounts (5, 10 and 20 wt%). The textual, structural properties, and surface morphology of all prepared materials were characterized by powder X-ray diffraction (XRD), N2 sorption isotherms, transmission electron microscopy(TEM) and Fourier transform infrared (FTIR) spectroscopy. Carbon dioxide capture capacity of amine-modified mesoporous carbon was obtained by thermogravimetric analysis (TGA) and volumetric adsorption analyzer (BET); the latter was also used to investigate the adsorption performance on CO2/N ratio. The reaction mechanisms of CO2 adsorption on amine-grafted OMCA were confirmed by infrared spectroscopy. The experimental results indicated that the optimal amine loaded amount is 10 wt% for OMCA-TEPA and OMCA-TAEA material. OMCA-TEPA-10 has highest adsorption amount. The results of the volumetric method showed that OMCA- TEPA-10 also had the highest chemical adsorption amounts, 13.23 μg/m2,which was more than OMCA-TAEA-10, 12.96 μg/m2 and OMCA-PEI-10, 7.03 μg/m2. The CO2/N molar ratio were 0.027、0.037 and 0.031, respectively. OMCA-TEPA-10 had highest chemical adsorption amounts but lowest CO2/N ratio due to the steric hindrance. By in-situ FTIR spectroscopy, we showed that the amine groups reacted with CO2 and formed carbamic acids and carbamate under dry conditions. The intensities of ammonium carbamate, carbamic acids and carbamate changed with temperature, and the chemical adsorption intensities had the same trends
Transverse-electric Brewster effect enabled by nonmagnetic two-dimensional materials
No full textDiscovered in the 19th century, the Brewster effect is known to occur for transverse-magnetic waves in regular optical dielectrics; however, it is believed to arise for transverse-electric (TE) waves only in systems with magnetic responses, i.e., nonunity effective relative permeability. This paper introduces a scheme to realize the TE Brewster effect in a homogeneous dielectric interface without magnetic responses, by adding ultrathin two-dimensional (2D) materials such as graphene. In particular, the effect remains even for waves approaching normal incidence, spanning from terahertz to visible frequencies. In contrast to the conventional Brewster effect, the graphene-assisted TE Brewster effect is asymmetric, and can be achieved only when the incidence is from the higher-refractive-index side. Moreover, graphene layers can tailor a total-internal-reflection dielectric interface into zero reflection, accompanied by perfect absorption. This control over TE waves enabled by ultrathin 2D materials may lead to a variety of applications, such as atomically thin absorbers, polarizers, and antireflection coating.Massachusetts Institute of Technology. Institute for Soldier Nanotechnologies (W911NF-13-D-0001)Solid-State Solar-Thermal Energy Conversion Center (DESC0001299
Simulated Stochastic Approximation Annealing for Global Optimization With a Square-Root Cooling Schedule
No full textSimulated annealing has been widely used in the solution of optimization problems. As known by many researchers, the global optima cannot be guaranteed to be located by simulated annealing unless a logarithmic cooling schedule is used. However, the logarithmic cooling schedule is so slow that no one can afford to use this much CPU time. This article proposes a new stochastic optimization algorithm, the so-called simulated stochastic approximation annealing algorithm, which is a combination of simulated annealing and the stochastic approximation Monte Carlo algorithm. Under the framework of stochastic approximation, it is shown that the new algorithm can work with a cooling schedule in which the temperature can decrease much faster than in the logarithmic cooling schedule, for example, a square-root cooling schedule, while guaranteeing the global optima to be reached when the temperature tends to zero. The new algorithm has been tested on a few benchmark optimization problems, including feed-forward neural network training and protein-folding. The numerical results indicate that the new algorithm can significantly outperform simulated annealing and other competitors. Supplementary materials for this article are available online.Faming Liang is Professor (E-mail: [email protected]), and Yichen Cheng is Graduate Student (E-mail: [email protected]), Department of Statistics, Texas A&M University, College Station, TX 77843. Guang Lin is Research Scientist, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MSIN K7-90, Richland, WA 99352 (E-mail: [email protected]). Liang's research was partially supported by grants from the National Science Foundation (DMS-1106494 and DMS-1317131) and the award (KUS-C1-016-04) made by King Abdullah University of Science and Technology (KAUST). The authors thank the editor, associate editor, and three referees for their constructive comments, which have led to significant improvement of this article
Author Correction: Transiting consolidated ice strongly influenced polynya area during a shrink event in Terra Nova Bay in 2013
No full textIn this article the author name Matthew Mazloff was incorrectly written as Matthew Mazloeff. The original article has been corrected
Raw Data for "On-demand cell-autonomous gene therapy for brain circuit disorders", Qiu et al. 2022 Science
No full textRaw Data for Qui et al. 2022 10.1126/science.abq6656
On-demand cell-autonomous gene therapy for brain circuit disorders
Yichen Qiu, Nathanael O’Neill, Benito Maffei, Clara Zourray, Amanda Almacellas Barbanoj, Jenna C. Carpenter,Steffan P. Jones, Marco Leite, Thomas J. Turner, Francisco C. Moreira, Albert Snowball, Tawfeeq Shekh-Ahmad, Vincent Magloire, Serena Barral, Manju A. Kurian, Matthew C. Walker, Stephanie Schorge, Dimitri M. Kullmann, Gabriele Lignani
Content:
EEG
MEA
Immuno
Patch Clamp Electrophysiology
All data are in a open source format. MEA files can be analysed using the MATLAB-based developed by Prof Michela Chiappalone and requests should be direct to:
Michela Chiappalone [email protected]
Ilaria Colombi [email protected]
EEG files are .zip with different transmitters. See EEG_Keys.xlxs for whcih virus was used in each animal.
MEA files are divided in 2 separate .zip: 1. Fig2 and Fig S3 and S7. 2. Fig S6.
Immuno: all the raw images are in the .zip file seprated by Figure #
Patch Clamp Electrophysiology: all the raw .abf files are in the .zip file separated by Figure #
For more info or to request materials please contact the corrsponding author Gabriele Lignani [email protected]
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What Is an Author's Role in the AI Era? Demystifying the Black Box of Human-AI Collaborative Creation Through an "Aesthetic Judgment" Study of the novel Solid Reference Frame Manuscript
No full textThis project repository establishes a permanent timestamp for a study that rethinks Roland Barthes' proclamation of the "death of the author" for the AI era. It engages with Michel Foucault's concept of "author-function" to propose "Aesthetic Judgment" as a new theoretical framework for human-AI collaborative creation. This framework reconceptualizes AI as a "critical partner"—a source of provocation and challenge. The human author, in turn, exercises decisive curatorial power through four key operations: 1) The Right to Question, 2) The Right to Select, 3) The Right to Arbitrate, and 4) The Right to Integrate.
Employing a "Process-Tracing" methodology, the research analyzes the complete manuscript of the novel Solid Reference Frame to demystify the creative "black box." This empirical study aims to demonstrate how the human author's role is transformed from a solitary genius into a systemic architect of meaning, thereby asserting a new, viable author-function for the digital age
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Altered spermatogenesis of death ligand gene deficient mice and the influence of phthalates in germ cell apoptosis and enhanced testicular cancer progression
No full texttextTesticular germ cell apoptosis is a process that begins in early development and continues in the adult testis. It is important during spermatogenesis for maintaining homeostasis of different types of germ cells. The number of sperm produced depends on the supportive capacity of surrounding Sertoli cells, which provide nutrition and an adaptive environment for growth and development of the germ cells. There are two major pathways that regulate germ cell apoptosis: extrinsic and intrinsic. We hypothesize that Sertoli cells use the extrinsic pathway to eliminate germ cells when exposed to phthalates, a common Sertoli cell toxicant.
Death ligands, which are involved in the extrinsic pathway, were used in this research to test this hypothesis. Here, we demonstrate that: 1) the loss of FasL and TRAIL protein expression results in decreased production of mature spermatids in the adult testis, likely as a result of alterations in germ cell homeostatsis during the first wave of spermatogenesis. 2) The high baseline incidence of germ cell apoptosis in peripubertal FasL-/- and TRAIL-/- mice is correlated with increases in levels of TRAIL and FasL, respectively. 3) The decline in germ cell apoptosis observed after MEHP treatment in FasL-/- mice closely corresponds to the occurrence of increased levels of c-FLIP. 4) A more predominant role of FasL occurs in controlling the proper number of germ cells during the first wave of spermatogenesis in peri-pubertal mice. TRAIL is more critical for maintaining long-term homeostasis of the germ cell population in adult testis as well as in the reproductive function. 5) Several possible genes are involved in the altered spermatogenesis and development in the testis of gene-deficient mice. 6) Findings described in Chapter 6 indicate cellular mechanisms triggered by MEHP exposure that act to enhance tumor progression/metastasis in testicular embryonal carcinoma cells (NT2/D1).
Taken together, these novel findings provide important mechanistic insights into the functional roles of FasL in the testis at distinct developmental periods and further indicate that FasL itself is required for the regulation of c-FLIP levels in the testis. Additionally, exposure to environmental toxicants, such as the phthalates, can enhance testicular cancer metastasis and invasion.Pharmaceutical Science
Tailored family adaptation to living in a zero-energy house: Occupant’s crises and conflicts with a heat pump-based system
No full textBackgroundThis project belongs to the IEBB project, which advocates for the renovation of ‘zero energy houses’ (ZEH) that synergize insulation and heat pump systems for energy conservation. The ZEH’s energy-saving efficiency depends on user behaviour. From a systems perspective, improper human interactions hinder energy saving, while occupants may find system responses that conflict with their preferences. This study delves into these conflicts and crises, highlighting the variance in post-occupancy adaptation influenced by individual perceptions and familial interplay. The project’s zenith aim is to tailor adaptation, ensuring co-performance between the heat pumpsystem and households. Key InsightIn researching residents’ responses to the ‘routine crisis’ introduced by a new system, I discovered that these ‘crises’ could be productive, stimulating household engagement and fostering harmonious interactions with ZEH systems. This insight gave rise to the concept of the ‘enacted interface’ - a distinctive bridge between residents and their automated homes that supports the adaptation process. Through analysis, I identified elements that amplify residents’ engagement with ‘crises’ and observed the influence of family diversity on individual perceptions and responses to them. The results are manifested in two interrelated frameworks: one describing the ubiquity of ‘crises’ and another characterising the classification and impact of different elements.DesignThis design aims to make households curious about ‘crises’ and guide them towards tailored adaptations to new tech. The ‘Clock’ thermostat provides a consistent interface for temperature adjustments, while the ‘Feeling Message Board’ suggests lifestyle tips based on the user’s emotional input and changing scenarios. Both reinforce the system’s ability to communicate contextual and real-time status, motivating users to actively engage with its functions. Additionally, the design stimulates family discussions about the indoor environment and promotes collaborative responses to ‘crises’. Through co-performance of the system’s dynamic feedback and the household’s proactive exploration, the aim is to facilitate tailored adaptation.IEBB projectIntegrated Product Desig
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