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Monaco计划系统中Conformality函数对宫颈癌容积旋转调强计划的影响
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作者 郗旺 赵媛媛 +2 位作者 王小秋 陈晓南 何瑞龙 《生物医学工程与临床》 CAS 2024年第4期515-520,共6页
目的 探讨Monaco计划系统中Conformality函数的不同参数值对计划质量的影响。方法 选择15例宫颈癌患者,年龄46~74岁,中位年龄51岁。分别采用Conformality函数参数值为0.25、0.50、0.75、1.00,以及不加函数设计容积旋转调强放射治疗(VMAT... 目的 探讨Monaco计划系统中Conformality函数的不同参数值对计划质量的影响。方法 选择15例宫颈癌患者,年龄46~74岁,中位年龄51岁。分别采用Conformality函数参数值为0.25、0.50、0.75、1.00,以及不加函数设计容积旋转调强放射治疗(VMAT)计划,评估靶区及危及器官(OAR)剂量学参数和20 Gy、30 Gy、40 Gy等剂量线的体积和计划执行效率。结果 不同Conformality函数参数值计划的靶区剂量学差异均有统计学意义(P <0.05)。Conformality函数参数值为0.25时,靶区的Dmax、Dmin、Dmean与不加函数的增减幅度分别为2.45%、-0.96%、1.48%,适形度指数(CI)、均匀性指数(HI)增加0.05、0.04。当Conformality函数参数值> 0.50时,CI、HI基本无改变。小肠、结肠、左右股骨头的剂量学差异无统计学意义(P> 0.05)。当Conformality函数参数值为0.25时,直肠的V30、V40[(81.80±7.74)%、(63.44±10.23)%]、膀胱V30、V40[(78.82±5.69)%、(56.40±9.33)%]、正常组织V_(20)、V_(30)、V_(40)的体积[(6 137.64±622.88) cm^(3)、(2 903.55±221.08) cm^(3)、(1 862.93±112.81) cm^(3)]最低。Conformality函数在不同参数之下,膀胱、直肠V_(30)、V_(40)差异均具有统计学意义(P <0.05)。随着Conformality函数参数值增大机器参数值随之减小,机器跳数(MU)、控制点个数(CP)、执行时间(DT)在各Conformality函数参数值之间差异均有统计学意义(P <0.05)。结论 对于宫颈癌在Monaco计划系统中恰当使用Conformality函数设计计划可以提高计划质量,参数值设置在0.25~0.75为宜。综合剂量学参数及计划执行效率,推荐使用0.50。 展开更多
关键词 Monaco计划系统 宫颈癌 conformality函数 剂量学
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3D‑Printed Carbon‑Based Conformal Electromagnetic Interference Shielding Module for Integrated Electronics 被引量:3
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作者 Shaohong Shi Yuheng Jiang +5 位作者 Hao Ren Siwen Deng Jianping Sun Fangchao Cheng Jingjing Jing Yinghong Chen 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第5期87-101,共15页
Electromagnetic interference shielding(EMI SE)modules are the core com-ponent of modern electronics.However,the tra-ditional metal-based SE modules always take up indispensable three-dimensional space inside electroni... Electromagnetic interference shielding(EMI SE)modules are the core com-ponent of modern electronics.However,the tra-ditional metal-based SE modules always take up indispensable three-dimensional space inside electronics,posing a major obstacle to the integra-tion of electronics.The innovation of integrating 3D-printed conformal shielding(c-SE)modules with packaging materials onto core electronics offers infinite possibilities to satisfy ideal SE func-tion without occupying additional space.Herein,the 3D printable carbon-based inks with various proportions of graphene and carbon nanotube nanoparticles are well-formulated by manipulating their rheological peculiarity.Accordingly,the free-constructed architectures with arbitrarily-customized structure and multifunctionality are created via 3D printing.In particular,the SE performance of 3D-printed frame is up to 61.4 dB,simultaneously accompanied with an ultralight architecture of 0.076 g cm^(-3) and a superhigh specific shielding of 802.4 dB cm3 g^(-1).Moreover,as a proof-of-concept,the 3D-printed c-SE module is in situ integrated into core electronics,successfully replacing the traditional metal-based module to afford multiple functions for electromagnetic compatibility and thermal dissipa-tion.Thus,this scientific innovation completely makes up the blank for assembling carbon-based c-SE modules and sheds a brilliant light on developing the next generation of high-performance shielding materials with arbitrarily-customized structure for integrated electronics. 展开更多
关键词 3D printing Carbon-based nanoparticles conformal electromagnetic interference shielding Integrated electronics
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Gelatin-Based Metamaterial Hydrogel Films with High Conformality for Ultra-Soft Tissue Monitoring 被引量:1
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作者 Yuewei Chen Yanyan Zhou +10 位作者 Zihe Hu Weiying Lu Zhuang Li Ning Gao Nian Liu Yuanrong Li Jing He Qing Gao Zhijian Xie Jiachun Li Yong He 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第2期347-364,共18页
Implantable hydrogel-based bioelectronics(IHB)can precisely monitor human health and diagnose diseases.However,achieving biodegradability,biocompatibility,and high conformality with soft tissues poses significant chal... Implantable hydrogel-based bioelectronics(IHB)can precisely monitor human health and diagnose diseases.However,achieving biodegradability,biocompatibility,and high conformality with soft tissues poses significant challenges for IHB.Gelatin is the most suitable candidate for IHB since it is a collagen hydrolysate and a substantial part of the extracellular matrix found naturally in most tissues.This study used 3D printing ultrafine fiber networks with metamaterial design to embed into ultra-low elastic modulus hydrogel to create a novel gelatin-based conductive film(GCF)with mechanical programmability.The regulation of GCF nearly covers soft tissue mechanics,an elastic modulus from 20 to 420 kPa,and a Poisson’s ratio from-0.25 to 0.52.The negative Poisson’s ratio promotes conformality with soft tissues to improve the efficiency of biological interfaces.The GCF can monitor heartbeat signals and respiratory rate by determining cardiac deformation due to its high conformability.Notably,the gelatin characteristics of the biodegradable GCF enable the sensor to monitor and support tissue restoration.The GCF metamaterial design offers a unique idea for bioelectronics to develop implantable sensors that integrate monitoring and tissue repair and a customized method for endowing implanted sensors to be highly conformal with soft tissues. 展开更多
关键词 Implantable hydrogel-based bioelectronics conformality 3D printing Metamaterial design
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Conformal ECO寄存器新增的扫描链自动化接入方案
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作者 曾子豪 《电子技术应用》 2024年第8期17-20,共4页
随着芯片规模的增加,ECO的需求和大小也随之增加,其中当新增寄存器数量达到百位量级时,人工接入扫描链难度也将急剧上升。基于Cadence的Conformal和Innovus等工具,在综合考量逻辑正确性和中后端物理实现可行性的基础上,采用归一思路下的... 随着芯片规模的增加,ECO的需求和大小也随之增加,其中当新增寄存器数量达到百位量级时,人工接入扫描链难度也将急剧上升。基于Cadence的Conformal和Innovus等工具,在综合考量逻辑正确性和中后端物理实现可行性的基础上,采用归一思路下的“S”型连线和room值下的再分组等方法,实现了上述问题的自动化和高效化解决,在逻辑上确保了时钟域一致性等问题,物理上同时兼顾了布局布线优化和最大扫描链长度。并且其自动化的高效性,在项目实践中能够快速完成上百数量寄存器的扫描链接入。 展开更多
关键词 conformal ECO 扫描链 新增寄存器 自动化
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Classifying rockburst with confidence:A novel conformal prediction approach
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作者 Bemah Ibrahim Isaac Ahenkorah 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第1期51-64,共14页
The scientific community recognizes the seriousness of rockbursts and the need for effective mitigation measures.The literature reports various successful applications of machine learning(ML)models for rockburst asses... The scientific community recognizes the seriousness of rockbursts and the need for effective mitigation measures.The literature reports various successful applications of machine learning(ML)models for rockburst assessment;however,a significant question remains unanswered:How reliable are these models,and at what confidence level are classifications made?Typically,ML models output single rockburst grade even in the face of intricate and out-of-distribution samples,without any associated confidence value.Given the susceptibility of ML models to errors,it becomes imperative to quantify their uncertainty to prevent consequential failures.To address this issue,we propose a conformal prediction(CP)framework built on traditional ML models(extreme gradient boosting and random forest)to generate valid classifications of rockburst while producing a measure of confidence for its output.The proposed framework guarantees marginal coverage and,in most cases,conditional coverage on the test dataset.The CP was evaluated on a rockburst case in the Sanshandao Gold Mine in China,where it achieved high coverage and efficiency at applicable confidence levels.Significantly,the CP identified several“confident”classifications from the traditional ML model as unreliable,necessitating expert verification for informed decision-making.The proposed framework improves the reliability and accuracy of rockburst assessments,with the potential to bolster user confidence. 展开更多
关键词 ROCKBURST Machine learning Uncertainty quantification conformal prediction
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Research status and challenges in the manufacturing of IR conformal optics
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作者 Jianbo Zhao Sheng Wang +2 位作者 Chunyu Zhang Jinhu Wang Qingliang Zhao 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第10期154-172,共19页
The infrared conformal window is one of the most critical components in aircraft.Conformal windows with high performance bring low aberrations,high aerodynamic performance,reliability in extreme working environments,a... The infrared conformal window is one of the most critical components in aircraft.Conformal windows with high performance bring low aberrations,high aerodynamic performance,reliability in extreme working environments,and added value for aircraft.Through the past decades,remarkable advances have been achieved in manufacturing technologies for conformal windows,where the machining accuracy approaches the nanometer level,and the surface form becomes more complex.These advances are critical to aircraft development,and these manufacturing technologies also have significant reference values for other directions of the ultra-precision machining field.In this review,the infrared materials suitable for manufacturing conformal windows are introduced and compared with insights into their performances.The remarkable advances and concrete work accomplished by researchers are reviewed.The challenges in manufacturing conformal windows that should be faced in the future are discussed. 展开更多
关键词 conformal optics Window and dome Infrared material Ultra-precision grinding POLISHING Measurement
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Effective approach for conformal subarray design based on maximum entropy of planar mappings
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作者 Xiao-Dong Zheng Sheng-Teng Shi +3 位作者 Jun Ou-Yang Feng Yang Qammer Abbasi Abubakar Sharif 《Journal of Electronic Science and Technology》 EI CAS CSCD 2024年第3期16-25,共10页
In this paper,an effective algorithm for optimizing the subarray of conformal arrays is proposed.The method first divides theconformal array into several first-level subarrays.It uses the X algorithm to solve the feas... In this paper,an effective algorithm for optimizing the subarray of conformal arrays is proposed.The method first divides theconformal array into several first-level subarrays.It uses the X algorithm to solve the feasible solution of first-level subarray tiling and employs the particle swarm algorithm to optimize the conformal array subarray tiling scheme with the maximum entropy of the planar mapping as the fitness function.Subsequently,convex optimization is applied to optimize the subarray amplitude phase.Data results verify that the method can effectively find the optimal conformal array tiling scheme. 展开更多
关键词 conformal array Irregular arrays Particle swarm optimal algorithm Maximum entropy model
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Thin-Shell Wormholes Admitting Conformal Motions in Spacetimes of Embedding Class One
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作者 Peter K. F. Kuhfittig 《International Journal of Astronomy and Astrophysics》 2024年第3期162-171,共10页
This paper discusses the feasibility of thin-shell wormholes in spacetimes of embedding class one admitting a one-parameter group of conformal motions. It is shown that the surface energy density σis positive, while ... This paper discusses the feasibility of thin-shell wormholes in spacetimes of embedding class one admitting a one-parameter group of conformal motions. It is shown that the surface energy density σis positive, while the surface pressure is negative, resulting in , thereby signaling a violation of the null energy condition, a necessary condition for holding a wormhole open. For a Morris-Thorne wormhole, matter that violates the null energy condition is referred to as “exotic”. For the thin-shell wormholes in this paper, however, the violation has a physical explanation since it is a direct consequence of the embedding theory in conjunction with the assumption of conformal symmetry. These properties avoid the need to hypothesize the existence of the highly problematical exotic matter. 展开更多
关键词 Thin-Shell Wormholes conformal Symmetry Embedding Class One Exotic Matter
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Momentum as Translations at Conformal Infinity
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作者 Richard James Petti Jacob Luke Graham 《Journal of Applied Mathematics and Physics》 2024年第4期1522-1540,共19页
Although General Relativity is the classic example of a physical theory based on differential geometry, the momentum tensor is the only part of the field equation that is not derived from or interpreted with different... Although General Relativity is the classic example of a physical theory based on differential geometry, the momentum tensor is the only part of the field equation that is not derived from or interpreted with differential geometry. This work extends General Relativity and Einstein-Cartan theory by augmenting the Poincaré group with projective (special) conformal transformations, which are translations at conformal infinity. Momentum becomes a part of the differential geometry of spacetime. The Lie algebra of these transformations is represented by vectorfields on an associated Minkowski fiber space. Variation of projective conformal scalar curvature generates a 2-index tensor that serves as linear momentum in the field equations of General Relativity. The computation yields a constructive realization of Mach’s principle: local inertia is determined by local motion relative to mass at conformal infinity in each fiber. The vectorfields have a cellular structure that is similar to that of turbulent fluids. 展开更多
关键词 Projective Symmetry conformal Symmetry MOMENTUM General Relativity Einstein-Cartan Mach’s Principle
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基于改进Conformer的新闻领域端到端语音识别 被引量:1
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作者 张济民 早克热·卡德尔 +2 位作者 艾山·吾买尔 申云飞 汪烈军 《中文信息学报》 CSCD 北大核心 2024年第4期156-164,共9页
目前,开源的中文语音识别数据集大多面向通用领域,缺少面向新闻领域的开源语音识别语料库,因此该文构建了面向新闻领域的中文语音识别数据集CH_NEWS_ASR,并使用ESPNET-0.9.6框架的RNN、Transformer和Conformer等模型对数据集的有效性进... 目前,开源的中文语音识别数据集大多面向通用领域,缺少面向新闻领域的开源语音识别语料库,因此该文构建了面向新闻领域的中文语音识别数据集CH_NEWS_ASR,并使用ESPNET-0.9.6框架的RNN、Transformer和Conformer等模型对数据集的有效性进行了验证,实验表明,该文所构建的语料在最好的模型上CER为4.8%,SER为39.4%。由于新闻联播主持人说话语速相对较快,该文构建的数据集文本平均长度为28个字符,是Aishell_1数据集文本平均长度的2倍;且以往的研究中训练目标函数通常为基于字或词水平,缺乏明确的句子水平关系,因此该文提出了一个句子层级的一致性模块,与Conformer模型结合,直接减少源语音和目标文本的表示差异,在开源的Aishell_1数据集上其CER降低0.4%,SER降低2%;在CH_NEWS_ASR数据集上其CER降低0.9%,SER降低3%,实验结果表明,该方法在不增加模型参数量的前提下能有效提升语音识别的质量。 展开更多
关键词 端到端语音识别 conformER 句子层级一致性
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基于层次化Conformer的语音合成
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作者 吴克伟 韩超 +2 位作者 孙永宣 彭梦昊 谢昭 《计算机科学》 CSCD 北大核心 2024年第2期161-171,共11页
语音合成需要将输入语句的文本转换为包含音素、单词和语句的语音信号。现有语音合成方法将语句看作一个整体,难以准确地合成出不同长度的语音信号。通过分析语音信号中蕴含的层次化关系,分别设计基于Conformer的层次化文本编码器和基于... 语音合成需要将输入语句的文本转换为包含音素、单词和语句的语音信号。现有语音合成方法将语句看作一个整体,难以准确地合成出不同长度的语音信号。通过分析语音信号中蕴含的层次化关系,分别设计基于Conformer的层次化文本编码器和基于Conformer的层次化语音编码器,并提出了一种基于层次化文本-语音Conformer的语音合成模型。首先,该模型根据输入文本信号的长度,构建层次化文本编码器,包括音素级、单词级、语句级文本编码器3个层次,不同层次的文本编码器描述不同长度的文本信息;并使用Conformer的注意力机制来学习该长度信号中不同时间特征之间的关系。利用层次化的文本编码器,能够找出语句中不同长度需要强调的信息,有效实现不同长度的文本特征提取,缓解合成的语音信号持续时间长度不确定的问题。其次,层次化语音编码器包括音素级、单词级、语句级语音编码器3个层次。每个层次的语音编码器将文本特征作为Conformer的查询向量,将语音特征作为Conformer的关键字向量和值向量,来提取文本特征和语音特征的匹配关系。利用层次化的语音编码器和文本语音匹配关系,可以缓解不同长度语音信号合成不准确的问题。所提模型的层次化文本-语音编码器可以灵活地嵌入现有的多种解码器中,通过文本和语音之间的互补,提供更为可靠的语音合成结果。在LJSpeech和LibriTTS两个数据集上进行实验验证,实验结果表明,所提方法的梅尔倒谱失真小于现有语音合成方法。 展开更多
关键词 语音合成 文本编码器 语音编码器 层次化模型 conformER
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基于Conformer的端到端中英文管制语音识别
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作者 孔建国 韩琪聪 +1 位作者 梁海军 李煜琨 《航空计算技术》 2024年第3期1-5,共5页
将语音识别技术应用到空中交通管理系统中可以提高飞行安全并降低管制员的工作负荷,目前已有的管制语音识别技术在中英文识别上效果较差,因此提出了一种基于Conformer-CTC/Attention的中英文管制语音识别框架。该方法使用基于改进的Conf... 将语音识别技术应用到空中交通管理系统中可以提高飞行安全并降低管制员的工作负荷,目前已有的管制语音识别技术在中英文识别上效果较差,因此提出了一种基于Conformer-CTC/Attention的中英文管制语音识别框架。该方法使用基于改进的Conformer共享编码器对输入序列进行语言分类并以参数有效的方式对音频序列的局部和全局相依性进行建模,添加了语种分类模块来判断输入语音序列的语种,还采用了CTC解码器和注意力解码器联合解码的多任务建模方法。最后在建立的民航数据集对所提出的框架进行验证,试验结果表明,Conformer-CTC/Attention(Language-Category)相对于基线模型错误率降低,识别效果达到预期。 展开更多
关键词 空中交通管制 中英文语音识别 conformer-CTC/Attention 多任务学习 端到端
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Conformal Human–Machine Integration Using Highly Bending‑Insensitive,Unpixelated,and Waterproof Epidermal Electronics Toward Metaverse 被引量:1
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作者 Chao Wei Wansheng Lin +8 位作者 Liang Wang Zhicheng Cao Zijian Huang Qingliang Liao Ziquan Guo Yuhan Su Yuanjin Zheng Xinqin Liao Zhong Chen 《Nano-Micro Letters》 SCIE EI CAS CSCD 2023年第11期140-156,共17页
Efficient and flexible interactions require precisely converting human intentions into computer-recognizable signals,which is critical to the breakthrough development of metaverse.Interactive electronics face common d... Efficient and flexible interactions require precisely converting human intentions into computer-recognizable signals,which is critical to the breakthrough development of metaverse.Interactive electronics face common dilemmas,which realize highprecision and stable touch detection but are rigid,bulky,and thick or achieve high flexibility to wear but lose precision.Here,we construct highly bending-insensitive,unpixelated,and waterproof epidermal interfaces(BUW epidermal interfaces)and demonstrate their interactive applications of conformal human–machine integration.The BUW epidermal interface based on the addressable electrical contact structure exhibits high-precision and stable touch detection,high flexibility,rapid response time,excellent stability,and versatile“cut-and-paste”character.Regardless of whether being flat or bent,the BUW epidermal interface can be conformally attached to the human skin for real-time,comfortable,and unrestrained interactions.This research provides promising insight into the functional composite and structural design strategies for developing epidermal electronics,which offers a new technology route and may further broaden human–machine interactions toward metaverse. 展开更多
关键词 Carbon-based functional composite Multifunctional epidermal interface Property modulation Addressable electrical contact structure conformal human–machine integration
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基于Conformer的端到端语音识别方法
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作者 胡从刚 申艺翔 +1 位作者 孙永奇 赵思聪 《计算机应用研究》 CSCD 北大核心 2024年第7期2018-2024,共7页
针对Conformer编码器的声学输入网络对FBank语音信息提取不足和通道特征信息缺失问题,提出一种RepVGG-SE-Conformer的端到端语音识别方法。首先,利用RepVGG的多分支结构,增强模型的语音信息提取能力,而在模型推理时通过结构重参数化将... 针对Conformer编码器的声学输入网络对FBank语音信息提取不足和通道特征信息缺失问题,提出一种RepVGG-SE-Conformer的端到端语音识别方法。首先,利用RepVGG的多分支结构,增强模型的语音信息提取能力,而在模型推理时通过结构重参数化将多分支融合为单分支,以降低计算复杂度、加快模型推理速度。然后,利用基于压缩和激励网络的通道注意力机制弥补缺失的通道特征信息,以提高语音识别准确率。最后,在公开数据集Aishell-1上的实验结果表明:相较于Conformer,所提出方法的字错误率降低了10.67%,验证了方法的先进性。此外,RepVGG-SE声学输入网络能够有效提高多种Transformer变体的端到端语音识别模型的整体性能,具有很好的泛化能力。 展开更多
关键词 语音识别 conformER RepVGG 压缩和激励网络
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Soft,body conformable electronics for thermoregulation enabled by kirigami 被引量:1
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作者 Lung Chow Guangyao Zhao +17 位作者 Pengcheng Wu Xingcan Huang Jiyu Li Jian Li Wanying Wang Guihuan Guo Zhiyuan Li Jiachen Wang Jingkun Zhou Yawen Yang Yuyu Gao Binbin Zhang Qiang Zhang Dengfeng Li Ya Huang Kuanming Yao Jian Lu Xinge Yu 《Bio-Design and Manufacturing》 SCIE EI CAS CSCD 2024年第4期453-462,共10页
The application of thermoelectric devices(TEDs)for personalized thermoregulation is attractive for saving energy while balancing the quality of life.TEDs that directly attach to human skin remarkably minimized the ene... The application of thermoelectric devices(TEDs)for personalized thermoregulation is attractive for saving energy while balancing the quality of life.TEDs that directly attach to human skin remarkably minimized the energy wasted for cooling the entire environment.However,facing the extreme dynamic geometry change and strain of human skin,conventional TEDs cannot align with the contour of our bodies for the best thermoregulation effect.Hence,we designed a kirigami-based wearable TED with excellent water vapor permeability,flexibility,and conformability.Numerical analysis and experimental results reveal that our product can withstand various types of large mechanical deformation without circuit rupture.The stated outcome and proposed facile approach not only reinforce the development of wearable TEDs but also offer an innovative opportunity for different electronics that require high conformability. 展开更多
关键词 THERMOREGULATION THERMOELECTRIC Kirigami Body conformable WEARABLE
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基于时频感知双路径Conformer的语音增强
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作者 芮阳 高勇 《通信技术》 2024年第4期338-346,共9页
近年来,Conformer在语音领域的应用表现较为突出。该模块通过结合多头自注意力机制和卷积神经网络,能够同时关注短时和长时序列信息,从而在语音处理任务中表现出卓越的性能。在此基础上提出了一种基于时频感知双路径Conformer的语音增... 近年来,Conformer在语音领域的应用表现较为突出。该模块通过结合多头自注意力机制和卷积神经网络,能够同时关注短时和长时序列信息,从而在语音处理任务中表现出卓越的性能。在此基础上提出了一种基于时频感知双路径Conformer的语音增强网络(TFDPCNet)。首先,该网络将改进的Conformer结构作为核心,采用双路径结构,构成时频感知的双路径Conformer模块(TFDP-Conformer),增强了整体网络的时频提取能力;同时,为了减小时频特征融合的难度,提出了注意力门控交叉融合模块(AGCF),通过额外的注意力门进一步增强了网络训练过程中时频特征的交互,提高了时频特征的利用率;最后,引用度量鉴别器,并对其进行适当剪枝,使得增强后的音频和原始音频在量化评价指标上保持更高的一致性。实验结果表明,相比于TSTNN算法,TFDPCNet在主观和客观指标上都有明显提高。 展开更多
关键词 语音增强 双路径conformer 时频域 注意力门控交叉融合 度量鉴别器
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CONFORMALLY FLAT AFFINE HYPERSURFACES WITH SEMI-PARALLEL CUBIC FORM
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作者 徐辉阳 李策策 《Acta Mathematica Scientia》 SCIE CSCD 2023年第6期2413-2429,共17页
In this paper,we study locally strongly convex affine hypersurfaces with the vanishing Weyl curvature tensor and semi-parallel cubic form relative to the Levi-Civita connection of the affine metric.As a main result,we... In this paper,we study locally strongly convex affine hypersurfaces with the vanishing Weyl curvature tensor and semi-parallel cubic form relative to the Levi-Civita connection of the affine metric.As a main result,we classify these hypersurfaces as not being of a flat affine metric.In particular,2 and 3-dimensional locally strongly convex affine hypersurfaces with semi-parallel cubic forms are completely determined. 展开更多
关键词 affine hypersurface semi-parallel cubic form Levi-Civita connection conformally flat warped product
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2D Curves in Conformal Hyperquaternion Algebras H⊗2m
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作者 Grégoire Lutanda Panga 《Journal of Applied Mathematics and Physics》 2023年第10期2904-2912,共9页
The aim of this paper is to outline the conditions of a conformal hyperquaternion algebra H<sup>⊗2m</sup> in which a higher order plane curve can be described by generalizing the well-known cases of conics... The aim of this paper is to outline the conditions of a conformal hyperquaternion algebra H<sup>⊗2m</sup> in which a higher order plane curve can be described by generalizing the well-known cases of conics and cubic curves in 2D. In other words, the determination of the order of a plane curve through n points and its conformal hyperquaternion algebra H<sup>⊗2m</sup> is the object of this work. 展开更多
关键词 Clifford Algebra Hyperquaternion Algebra conformal Hyperquaternion Al-gebra
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Joint polarization and DOA estimation based on improved maximum likelihood estimator and performance analysis for conformal array
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作者 SUN Shili LIU Shuai +2 位作者 WANG Jun YAN Fenggang JIN Ming 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2023年第6期1490-1500,共11页
The conformal array can make full use of the aperture,save space,meet the requirements of aerodynamics,and is sensitive to polarization information.It has broad application prospects in military,aerospace,and communic... The conformal array can make full use of the aperture,save space,meet the requirements of aerodynamics,and is sensitive to polarization information.It has broad application prospects in military,aerospace,and communication fields.The joint polarization and direction-of-arrival(DOA)estimation based on the conformal array and the theoretical analysis of its parameter estimation performance are the key factors to promote the engineering application of the conformal array.To solve these problems,this paper establishes the wave field signal model of the conformal array.Then,for the case of a single target,the cost function of the maximum likelihood(ML)estimator is rewritten with Rayleigh quotient from a problem of maximizing the ratio of quadratic forms into those of minimizing quadratic forms.On this basis,rapid parameter estimation is achieved with the idea of manifold separation technology(MST).Compared with the modified variable projection(MVP)algorithm,it reduces the computational complexity and improves the parameter estimation performance.Meanwhile,the MST is used to solve the partial derivative of the steering vector.Then,the theoretical performance of ML,the multiple signal classification(MUSIC)estimator and Cramer-Rao bound(CRB)based on the conformal array are derived respectively,which provides theoretical foundation for the engineering application of the conformal array.Finally,the simulation experiment verifies the effectiveness of the proposed method. 展开更多
关键词 conformal array maximum likelihood(ML)estimator manifold separation technology(MST) parameter estimation Cramer-Rao bound(CRB).
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基于Conformable分数阶导数的灰色Bernoulli模型
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作者 骆世广 曾亮 《浙江大学学报(理学版)》 CAS CSCD 北大核心 2024年第2期196-204,共9页
为增强灰色Bernoulli模型对各种实际数据序列的适应性,借助分数阶微积分在描述复杂系统中的优势,提出了一种基于Conformable分数阶导数的灰色Bernoulli模型。研究发现,可通过改变结构参数将模型转换为不同的经典灰色预测模型,体现了其... 为增强灰色Bernoulli模型对各种实际数据序列的适应性,借助分数阶微积分在描述复杂系统中的优势,提出了一种基于Conformable分数阶导数的灰色Bernoulli模型。研究发现,可通过改变结构参数将模型转换为不同的经典灰色预测模型,体现了其统一性。此外,采用粒子群优化算法求解规划模型,获取了模型的最优超参数。最后,用所提模型和5个竞争模型对3个真实案例进行了预测建模,结果表明,所提模型的2项评估指标均优于5个竞争模型,验证了所提模型的有效性和可行性。 展开更多
关键词 灰色系统 conformable分数阶导数 灰色Bernoulli模型 粒子群优化算法
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