Extended Equal Service and Differentiated Service Models for Peer-to-Peer File Sharing

Jianwei Zhang,Yongchao Wang,Wei Xing,Dongming Lu 한국통신학회 2013 Journal of communications and networks Vol.15 No.2

Peer-to-peer (P2P) systems have proved the most effective and popular file sharing applications in recent years. Previous studies mainly focused on equal service and differentiated service strategies when peers have no initial data before their downloads. For an upload-constrained P2P file sharing system, wemodel both the equal service process and the differentiated service process when the initial data distribution of peers satisfies some special conditions. Moreover, we show how to minimize the time required to distribute the file to any number of peers. The proposed fluid-based models can reveal the intrinsic relations among the initial data amount, the peer set size, and the minimum last finish time. The closed-form expressions derived from the extended models can closely approximate chunk-based models and systems, especially for relatively large files. As an application of the extended models, we show how to provide differentiated service efficiently to multiple peer sets. Since no limits are imposed on the upload bandwidth of peers or the size of each peer set, we believe that our analytic process and the results achieved can provide not only fundamental insights into bandwidth allocation and data scheduling but also a helpful reference for both improving systemperformance and building an effective incentive mechanism for P2P file sharing systems.

Precise Tool Setting Method for CNC Machining Compound Spiral Antenna Based on Binocular Micro Stereo Vision

Wei Liu,Kai Zhao,Peng Gao,Ling Wang,Lichao Ding,Jianwei Ma,Zhenyuan Jia 한국생산제조학회 2014 한국생산제조시스템학회 학술발표대회 논문집 Vol.2014 No.9(2)

The actuation equation of macro-fiber composite coupled plate and its active control over the vibration of plate and shell

Tu, Jianwei,Zhang, Jiarui,Zhu, Qianying,Liu, Fan,Luo, Wei Techno-Press 2018 Structural monitoring and maintenance Vol.5 No.2

Plate and shell structure is widely applied in engineering, i.e. building roofs, aircraft wings, ship platforms, and satellite solar arrays. Its vibration problem has become increasingly prominent due to the tendency of lightening, upsizing and flexibility. As a new smart material with great actuating force and toughness, macro-fiber composite (MFC) is composed of piezoelectric fiber and epoxy resin basal body, which can be directly pasted onto the surface of plate and shell and is suitable for vibration control. This paper deduces the actuation equation of MFC coupled plate in different boundary conditions, an equivalent finite element modeling method is proposed which uses MFC actuating force as the applied excitation, and on this basis the active control simulation and experiment of MFC over plate and shell structure vibration are accomplished. The results indicate that MFC is able to implement effective control over plate and shell structure vibration in multi-band range. The comparison between experiment and simulation proves that the actuation equation deduced herein, effective and practicable, can be applied into the simulation calculation of MFC vibration control over plate and shell structure.

2,1,3-Benzothiadiazole-5,6-dicarboxylicimide-Based Polymer Semiconductors for Organic Thin-Film Transistors and Polymer Solar Cells

Yu, Jianwei,Ornelas, Joshua Loroñ,a,Tang, Yumin,Uddin, Mohammad Afsar,Guo, Han,Yu, Simiao,Wang, Yulun,Woo, Han Young,Zhang, Shiming,Xing, Guichuan,Guo, Xugang,Huang, Wei American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.48

<P>A series of polymer semiconductors incorporating 2,1,3-benzothiadiazole-5,6-dicarboxylicimide (BTZI) as strong electron-withdrawing unit and an alkoxy-functionalized head-to-head linkage containing bithiophene or bithiazole as highly electron-rich co-unit are designed and synthesized. Because of the strong intramolecular charge transfer characteristics, all three polymers BTZI-TRTOR (P1), BTZI-BTOR (P2), and BTZI-BTzOR (P3) exhibit narrow bandgaps of 1.13, 1.05, and 0.92 eV, respectively, resulting in a very broad absorption ranging from 350 to 1400 nm. The highly electron-deficient 2,1,3-benzothiadiazole-5,6-dicarboxylicimide and alkoxy-functionalized bithiophene (or thiazole) lead to polymers with low-lying lowest unoccupied molecular orbitals (-3.96 to -4.28 eV) and high-lying highest occupied molecular orbitals (-5.01 to -5.20 eV). Hence, P1 and P3 show substantial and balanced ambipolar transport with electron mobilities/hole mobilities of up to 0.86/0.51 and 0.95/0.50 cm(2) V-1 s(-1), respectively, and polymer P2 containing the strongest donor unit exhibited unipolar p-type performance with an average hole mobility of 0.40 cm(2) V-1 s(-1) in top-gate/bottom-contact thin-film transistors with gold as the source and drain electrodes. When incorporated into bulk heterojunction polymer solar cells, the narrow bandgap (1.13 eV) polymer P1 shows an encouraging power conversion efficiency of 4.15% with a relatively large open-circuit voltage of 0.69 V, which corresponds to a remarkably small energy loss of 0.44 eV. The power conversion efficiency of P1 is among the highest reported to date with such a small energy loss in polymer:fullerene solar cells.</P>

Extended Equal Service and Differentiated Service Models for Peer-to-Peer File Sharing

Zhang, Jianwei,Wang, Yongchao,Xing, Wei,Lu, Dongming The Korea Institute of Information and Commucation 2013 Journal of communications and networks Vol.15 No.2

Peer-to-peer (P2P) systems have proved the most effective and popular file sharing applications in recent years. Previous studies mainly focused on equal service and differentiated service strategies when peers have no initial data before their downloads. For an upload-constrained P2P file sharing system, we model both the equal service process and the differentiated service process when the initial data distribution of peers satisfies some special conditions. Moreover, we show how to minimize the time required to distribute the file to any number of peers. The proposed fluid-based models can reveal the intrinsic relations among the initial data amount, the peer set size, and the minimum last finish time. The closed-form expressions derived from the extended models can closely approximate chunk-based models and systems, especially for relatively large files. As an application of the extended models, we show how to provide differentiated service efficiently to multiple peer sets. Since no limits are imposed on the upload bandwidth of peers or the size of each peer set, we believe that our analytic process and the results achieved can provide not only fundamental insights into bandwidth allocation and data scheduling but also a helpful reference for both improving system performance and building an effective incentive mechanism for P2P file sharing systems.

Analysis of the Current Situation and Hot Spots of Music Education Research in Elementary Schools in China

赵薇(Wei Zhao),赵敬霞(JingXia Zhao),佘建位(JianWei She) Korea Institute for Humanities and Social Sciences 2023 Journal of Global Arts Studies (JGAS) Vol.1 No.1

[Background] Music education, as one of the crucial artistic courses in school education, constitutes an integral part of students' comprehensive development. The relevant studies on perception, along with the promulgation and implementation of the 2022 edition of China's “Compulsory Education Art Curriculum Standards”, have laid a new foundation for the upcoming round of transformative restructuring in music education classrooms. [Objective] The objective of this study is to analyze relevant academic journal literature on elementary school music education during the first two rounds of curriculum reforms in China (2002-2012-2022). This analysis aims to reveal the research status and hotspots in this field over the past two decades, providing cognitive support for the upcoming round of curriculum reforms. [Method] Literature retrieval was conducted on the China National Knowledge Infrastructure (CNKI) database, and CiteSpace visualization analysis software was utilized. Employing quantitative and visual methods, an exploration and analysis of high-frequency terms, high-centrality terms, and salient terms in 2363 articles were conducted, presenting the structure and evolutionary trends in the research field. [Results] It was found that over the past 20 years, research themes in Chinese elementary school music education have gradually evolved. Early studies primarily focused on pedagogical methods in primary school music classrooms, music education, and music teachers. In recent years, emerging research topics encompass core competencies, presentation activities, and music literacy. [Conclusion] The findings indicate that the hotspots in research on Chinese elementary school music education align closely with the directions of contemporary curriculum reforms. Achievements predominantly converge on specific classroom teaching objectives, but the research focus on classroom teaching content varies across different stages of curriculum reform. This panoramic view provides essential reference for future practitioners and researchers in elementary music education, while offering crucial data support for decision-makers. Clarifying the trajectory of existing research achievements during the forthcoming curriculum reform process will facilitate the sustainable development of both elementary music education and the quality of classroom teaching in China. 【背景】音乐教育作为学校教育的重要艺术课程之一,是学生全面发展的组成部分。对领略的相关研究及中国2022 年版《义务教育艺术课程标准》的颁布实施,为新一轮音乐教育的课堂变革奠定了新的基础。【目的】对中国前两轮课程改革期间(2002 年-2012 年-2022 年)的初等学校音乐教育研究的相关学术期刊文献进行分析,揭示近20 年来该领域的研究现状和热点,可以为新一轮的课程改革提供认知支持。【方法】在中国知网数据库进行文献检索,借助CiteSpace 可视化分析软件,通过计量统计方法和可视化方法,对2363 篇文献的高频词、高中心性词和突显性词等进行探索和分析,呈现了研究领域的结构和演化趋势。【结果】发现,在过去20 年里,中国初等学校音乐教育的研究主题逐步演变。早期研究主要关注小学音乐课堂的教学方法、音乐教育与音乐教师。而近年来,新兴研究议题涉及核心素养、展示活动、音乐素养等方面。【结论】表明,中国初等学校音乐教育研究热点内容紧随时代的课程改革方向,成果聚集于具体的课堂教学目标,但在不同的课改阶段对课堂教学内容的研究关注各有所侧重。这一全景图为未来初等音乐教育的实践者和研究者提供了重要的参考,同时为决策者提供了数据支持。为新一轮的课程改革理清已有研究成果脉络,有助于推进中国初等音乐教育和课堂教学质量的可持续发展。

Analysis and research on magnetic modulation mechanism of axial field flux‑switching composite machines

Rui Wang,Wei Zhang,Xiaobin Xu,Jianwei Zhao 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.5

To improve the performance of low-speed large-torque direct drive systems in limited space, an axial field flux-switching composite machine (AFFSCM) is proposed in this paper. The AFFSCM is composed of an axial field flux-switching permanent magnet machine (AFFSPMM) and magnetic gear. Therefore, it has the advantages of a compact structure, a large power/torque density, and a wide speed regulation range. First, the topology and magnetic modulation mechanism of the AFFSCM are investigated in detail. Then, the harmonic components of the inner/outer air-gap flux density are analyzed before and after the regulation of the rotary magnetic modulation ring. Based on this, the coupling conditions of the inner/ outer air-gap magnetic field are deduced. Then the AFFSCM is initially designed, a three-dimensional finite-element model of the AFFSCM is built, and the electromagnetic performances are analyzed by the finite-element method, including the flux density of the inner/outer air-gap, the speed, the static torque, etc. Next, the cogging torque of the AFFSPMM is analyzed and optimized based on the magnetic modulation mechanism to suppress the torque ripple of the AFFSCM. Finally, an 800 W prototype is constructed and related experiments are done to validate the AFFSCM.

천리안해양위성 2호(GOCI-II) 원격반사도품질 검증 시스템 적용 및 결과

배수정,이은경,Jianwei Wei,이경상,김민상,최종국,안재현 대한원격탐사학회 2023 大韓遠隔探査學會誌 Vol.39 No.6

천리안 해양위성 2호(Geostationary Ocean Color Imager-II, GOCI-II)에서 관측된 대기상층 복사휘도에서해양환경 분석이 가한 원격반사도(remote-sensing reflectance, Rrs) 자료를 얻기 위해서 복사 전달 모델 기반의 대기 보정을 수행한다. 이 Rrs는 다시 엽록소, 총부유사, 용존유기물 농도 등의 다양한 해양환경변수 산출에 이용되고 있기 때문에 대기보정은 모든 해색 산출물의 정확도에 영향을 주는 중요한 알고리즘이다. 맑은 해역에서는 대기의 복사휘도가 청색 파장대의 해수 복사휘도보다 10배 이상 높다. 따라서 대기보정 과정에서 1%의 대기 복사휘도 추정 오차가 10% 이상의 Rrs 오차를 유발할 수 있으며, 이처럼 대기보정은 매우 높은 오차 민감도를 가진 알고리즘이다. 그 결과 대기보정 산출물인 Rrs의 품질 평가는 신뢰성 있는 해양 위성 기반 자료 분석을위해 반드시 선행되어야 한다. 본 연구에서는 Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Bio-optical Archiveand Storage System (SeaBASS)을 통해 데이터베이스화 된 현장 측정 Rrs 기반 통계적 신뢰성을 평가하는 QualityAssurance (QA) 알고리즘을 GOCI-II의 분광 특성에 맞게 수정 및 적용하였다. 이 방법은 National Oceanic andAtmospheric Administration (NOAA)의 해색위성 자료처리 시스템에 공식적으로 적용되어 서비스 중이며, Rrs의 품질 분석 점수(0~1점)를 제공할 뿐 아니라 해수의 유형(23 유형)도 구분해 준다. 실제로 검보정 초기 단계의GOCI-II 자료에 QA를 적용한 결과, Rrs는 비교적 낮은 값인 0.625에서 가장 높은 빈도를 보여주었지만 추가적인 검보정을 통해 개선된 GOCI-II 대기보정 결과에 QA 알고리즘을 적용했을 시 기존보다 높은 0.875에서 가장 높은 빈도를 보여주었다. QA 알고리즘을 통한 해수 유형 분석 결과, 동해 및 남해 일부 그리고 북서태평양해역은 주로 탁도가 낮은 case-I 해역이었으며 서해 연안 및 동중국해는 주로 탁도가 높은 case-II 해역으로 구분되었다. 이처럼 QA 알고리즘의 적용을 통해 대기보정 과정에서 오차가 크게 발생한 Rrs 자료를 객관적으로 판별하여 배제할 수 있으며 이는 배포자료 및 검보정의 신뢰도 향상으로 이어질 수 있다. 본 방법은 추후 GOCIII의대기보정 flag에 적용되어 사용자들이 양질의 Rrs 자료만을 적용할 수 있도록 도움을 줄 것이다.

Asynchronous H∞ Dynamic Output Feedback Control for Markovian Jump Neural Networks with Time-varying Delays

Yuqian Lin,Guangming Zhuang,Jianwei Xia,Wei Sun,Junsheng Zhao 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.3

In this paper, the problem of asynchronous robust H∞ dynamic output feedback control for Markovian jump neural networks with norm-bounded parameter uncertainties and mode-dependent time-varying delays is investigated. The improved delay-dependent stochastic stability conditions and bounded real lemma are obtained by introducing the relaxation variables, which reduces the conservatism caused by boundary technology and model transformation. An improved Lyapunov-Krasovskii functional is constructed using linear matrix inequalities. On this basis, the solution of robust H∞ dynamic output feedback problem and sufficient conditions for solving the problem of asynchronous dynamic output feedback controller are given respectively. Asynchronous dynamic output feedback controller is constructed to ensure that the closed-loop mode-dependent time-varying delays Markovian jump neural networks achieve different convergence speeds. The given H∞ performance index is satisfied for the delays not bigger than a given upper bound. Numerical examples are employed to show the effectiveness and correctness of the method presented in this paper.

Mode-dependent H∞ Filtering for Time-varying Delays Neutral Jump Systems Based on FWM Technique

Guowei Zhao,Guangming Zhuang,Jianwei Xia,Wei Sun,Junsheng Zhao,Minsong Zhang 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.6

This paper is concerned with the problem of mode dependent H∞ filter for uncertainty Markovian jump system with neutral delay and retarded time-varying delay. By using free weight matrix (FWM) technique, the stability conditions of delay dependent are obtained under the framework of Lyapunov stability theory. Based on those result, the delay dependent conditions for full order and mode dependent Markovian jump linear filters are gained, which are expressed by Linear matrix inequalities (LMIs). Finally, a numerical example and a PEEC practical example are employed to prove the validity of the results.