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Scheduling Check-in Staff with Hierarchical Skills and Weekly Rotation Shifts
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作者 LU Min XU Tao FENG Xia 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2020年第4期638-645,共8页
The paper aims to schedule check-in staff with hierarchical skills as well as day and night shifts in weekly rotation.That shift ensures staff work at day in a week and at night for the next week.The existing approach... The paper aims to schedule check-in staff with hierarchical skills as well as day and night shifts in weekly rotation.That shift ensures staff work at day in a week and at night for the next week.The existing approaches do not deal with the shift constraint.To address this,the proposed algorithm firstly guarantees the day and night shifts by designing a data copy tactic,and then introduces two algorithms to generate staff assignment in a polynomial time.The first algorithm is to yield an initial solution efficiently,whereas the second incrementally updates that solution to cut off working hours.The key idea of the two algorithms is to utilize a block Gibbs sampling with replacement to simultaneously exchange multiple staff assignment.Experimental results indicate that the proposed algorithm reduces at least 15.6 total working hours than the baselines. 展开更多
关键词 check-in staff scheduling hierarchical skills weekly rotation shifts block Gibbs sampling
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Relationship between Sleep and Subjective Fatigue in Rotating Shift Nurses: Validation Using a Wearable Device
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作者 Yuko Yoshida Naomi Sumi +2 位作者 Naotaka Sugimura Fumie Nemoto Rika Yano 《Open Journal of Nursing》 2018年第4期272-280,共9页
The objective of this study was to determine if sleep indicators are associated with subjective fatigue in nurses working in a rotating, two-shift system with a 16-hour night shift, using the wearable device Fitbit On... The objective of this study was to determine if sleep indicators are associated with subjective fatigue in nurses working in a rotating, two-shift system with a 16-hour night shift, using the wearable device Fitbit One. Subjective fatigue was evaluated using the Subjective Fatigue Symptom Questionnaire (SFSQ), a rating scale developed by the Working Group for Occupational Fatigue of the Japan Society for Occupational Health. Subjects were asked to continuously wear a Fitbit One to obtain the following data: time in bed (TIB), deep sleep time, length and frequency of nighttime awakening, sleep efficiency, waking time, and bed time. Nurses had a mean age and standard deviation of 33.2 ± 7.5 years and had worked as nurses for 9.8 ± 6.2 years on average. Eight nurses were in their 20s (42.1%), 5 in their 30s (26.3%), and 6 in their 40s (31.6%). All participants were female. Participants’ SFSQ scores calculated from the 9 evenings in the study period were averaged to establish a threshold for categorizing high-fatigue (HF) and low-fatigue (LF) groups. No significant differences were found between HF and LF nurses in terms of TIB, deep sleep time, nighttime awakening time or frequency, or sleep efficiency on any type of day (as classified by shift, day off, etc.). Nurses in both groups woke up significantly later on days off and on pre-night-shift days than on day-shift days. These results demonstrate the variation in sleep patterns of nurses on a rotating, two-shift system between day-shift and night-shift days. 展开更多
关键词 FATIGUE rotatING shifts NURSE SLEEP
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Differences in Male Climacteric Symptoms and Lifestyle Depending on the Duration of Working among Rotating Night Shift Workers
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作者 Sachiko Kubo Toshiyuki Yasui +2 位作者 Reiko Okahisa Yukie Matsuura Masahito Tomotake 《Health》 2020年第12期1598-1609,共12页
<strong>Background:</strong> There are various health problems in rotating shift workers. There have been few studies on the associations of male climacteric symptoms with duration of working and lifestyle... <strong>Background:</strong> There are various health problems in rotating shift workers. There have been few studies on the associations of male climacteric symptoms with duration of working and lifestyle. <strong>Objective: </strong>The aim of this study was to determine the differences in male climacteric symptoms depending on the number of working years and to determine whether lifestyle habits differ depending on the number of working years in rotating shift workers. <strong>Methods:</strong> We collected participant’s data from the manufacturing companies in Japan during the period from March to May in 2017. We conducted a self-administered questionnaire survey in 1561 male rotating night shift workers. Male climacteric symptoms were evaluated by using the Aging Males’ Symptoms (AMS) rating scale. We analyzed 636 rotating shift workers aged over 40 years old whose all AMS data was collected. <strong>Results:</strong> A significant difference in psychological AMS score was found between men who had worked for 10 - 19 years (9.4 ± 3.9) and men who had worked for more than 40 years (7.6 ± 3.0) (p = 0.011). Sexual functional AMS score significantly differed depending on the number of working years (less than 10 years: 8.1 ± 3.9, 10 - 19 years: 9.8 ± 4.1, 20 - 29 years: 7.9 ± 3.3, 30 - 39 years: 9.3 ± 3.5, more than 40 years: 9.3 ± 3.5) (p < 0.001). The proportion of workers with a balanced meal intake was significantly lower in men who had worked for less than 10 years and the proportions of such workers were significantly higher in men who had worked for 10 - 19 years and for more than 40 years. The proportions of men who did not drink alcohol were high in men who had worked for less than 10 years and 20 - 29 years and low in men who had worked more than 30 years. <strong>Conclusion: </strong>Psychological AMS score and sexual functional AMS score are significantly different among the 5 groups according to the number of working years on rotating shift. In addition, well-balanced diet on day shift and reduction of alcohol drinking is a related-factor for long-term rotating night shift workers. 展开更多
关键词 rotating Night shift Workers Male Climacteric Symptoms Aging Male’s Symptoms Rating Scale Occupational Health Lifestyle Habit
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基于Mean Shift的目标平移与旋转跟踪 被引量:10
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作者 王长军 朱善安 《中国图象图形学报》 CSCD 北大核心 2007年第8期1367-1371,共5页
针对目前多数实时跟踪算法只能跟踪目标平移运动,不能跟踪旋转运动的问题,提出一种基于Mean Shift的快速旋转跟踪算法。该算法以目标区域的梯度方向分布(直方图)为特征,构造了可用Mean Shift算法寻优的相似度函数,将旋转跟踪转化为寻优... 针对目前多数实时跟踪算法只能跟踪目标平移运动,不能跟踪旋转运动的问题,提出一种基于Mean Shift的快速旋转跟踪算法。该算法以目标区域的梯度方向分布(直方图)为特征,构造了可用Mean Shift算法寻优的相似度函数,将旋转跟踪转化为寻优问题,并利用Mean Shift寻优过程收敛速度快的特点,有效跟踪目标旋转。又提出交替迭代的方法,将旋转跟踪与Meer的平移跟踪算法融合起来,构造了可以同时跟踪目标旋转和平移完整跟踪算法。 展开更多
关键词 梯度方向分布 Bhattacharyya相似度 Mean shift 旋转与平移 目标跟踪
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Walsh Spectrum Properties of Rotation Symmetric Boolean Function 被引量:1
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作者 WANG Yongjuan HAN Wenbao LI Shiqu 《Wuhan University Journal of Natural Sciences》 CAS 2006年第6期1862-1864,共3页
Rotation symmetric function was presented by Pieprzyk. The algebraic configuration of rotation symmetric(RotS) function is special. For a Rots n variables function f(x1, x2, …, xn) we have f(ρn^k (x1, x2, …x... Rotation symmetric function was presented by Pieprzyk. The algebraic configuration of rotation symmetric(RotS) function is special. For a Rots n variables function f(x1, x2, …, xn) we have f(ρn^k (x1, x2, …xn))=f(x1, x2, …, xn) for k=0, 1, …, n-1. In this paper, useing probability method we find that when the parameters of RotS function is under circular translation of indices, its walsh spectrum is invariant. And we prove the result is both sufficient and necessary. 展开更多
关键词 rotation symmetric function rotation shift Walsh spectra
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增强目标模型鲁棒性的Mean-shift算法
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作者 郭运艳 陈恳 +2 位作者 宋康康 刘哲 黄小霞 《宁波大学学报(理工版)》 CAS 2012年第4期25-28,共4页
针对传统Mean-shift算法中颜色核函数直方图对目标特征描述较弱的缺点,提出了一种联合目标特征点的二维结构信息和颜色信息的Mean-shift改进算法.改进算法细化了Harris检测算子的角点响应阈值,提取出更多的目标特征点计算其方向分布,并... 针对传统Mean-shift算法中颜色核函数直方图对目标特征描述较弱的缺点,提出了一种联合目标特征点的二维结构信息和颜色信息的Mean-shift改进算法.改进算法细化了Harris检测算子的角点响应阈值,提取出更多的目标特征点计算其方向分布,并以方向与部分颜色特征的直方图构建目标模型,该模型能显著区分目标与背景.实验对不同算法进行了仿真及性能比较,结果表明:提出的改进算法在一定的复杂场景中提高了跟踪精度,且具有较好的鲁棒性. 展开更多
关键词 Mean—shift Harris检测算子 旋转不变性 联合直方图
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The impact of sleep quality on reported anxiety and fatigue among shift nurses: The mediating role of resilience 被引量:1
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作者 Xin-Ge WANG Yan-Yan LUO Shuan-Rong LI 《Journal of Integrative Nursing》 2020年第4期190-195,共6页
Aims:The aim of this article is to explore the relation of sleep quality,anxiety status,fatigue level and psychological resilience among rotating‑shift nurses,thus,to propose solutions and promote physical and psychol... Aims:The aim of this article is to explore the relation of sleep quality,anxiety status,fatigue level and psychological resilience among rotating‑shift nurses,thus,to propose solutions and promote physical and psychological health of shift nurses.Methods:The cross‑sectional survey was performed on 263 clinical nurses recruited from three tertiary hospitals of Xinxiang City,Henan Province,China from October 2017 to June 2018.The questionnaire survey was conducted using Pittsburgh Sleep Quality Index(PSQI)for measuring nurses’sleep quality,connor‑davidson resilience scale(CD‑RISC)for measuring their psychological resilience,self‑rating anxiety scale(SAS)for measuring their anxiety status,and Fatigue‑14 Scale for measuring their fatigue.The relationship among above indicators were analysed using Pearson correlation analysis.The mediating effect of psychological resilience on the process of sleep quality impacting anxiety and fatigue was analyzed using Wen’s causual steps method and linear regression.Results:The mean CD‑RISC score of shift nurses was 57.76±11.90,which indicated that resilience level was at a medium level.The mean of PSQI,SAS and total fatigue score was(7.53±2.83),(50.56±9.57)and(7.81±9.42),respectively.Resilience could negatively predict the anxiety state(β=−0.366,P<0.01)and fatigue(β=−0.197,P<0.01).Sleep quality could positively predict anxiety(β=0.395,P<0.01)and fatigue level(β=0.495,P<0.01)for shift nurses.The mediating effects of resilience upon sleep quality and anxiety or fatigue was 0.044 and 0.026,respectively.Conclusion:The resilience could fuel sleep quality and reduce the occurrence of negative emotion and fatigue among shift nurses. 展开更多
关键词 ANXIETY FATIGUE RESILIENCE rotating shift nurses sleep quality
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The Association of Night Shift Work with the Development of Breast Cancer in Women
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作者 P. I. J. Moukangoe M. S. Jansen van Rensburg 《Open Journal of Epidemiology》 2015年第1期14-21,共8页
Breast cancer is a serious public health concern in South Africa and globally. It is estimated that one in seven South Africans will develop cancer in their lifetime. According to a case-controlled study, 80% of cance... Breast cancer is a serious public health concern in South Africa and globally. It is estimated that one in seven South Africans will develop cancer in their lifetime. According to a case-controlled study, 80% of cancer cases are thought to be due to external, non-inherited factors, which could potentially have been prevented. The objectives of the current case-control study were: 1) to determine the relationship between night shift work and the development of breast cancer;2) to explore the relationship between night shift work and other types of cancer;3) to explore any difference between night shift work and breast cancer, and night shift work and other types of cancer. A total of 106 research participants were selected using non-probability, convenience sampling methods and interviewed using a structured questionnaire. Seventy-two (68%) of the women who were interviewed were black, while 32% (n = 35) were white. Of the 106 research participants, 82% (n = 87) had a history of being employed, while 18% (n = 19) had never been employed. Analysed data showed that 29% (n = 31) of the women had a history of working night shift. Of the 31 research participants who reported having worked night shift, 90% (n = 28) had actually done rotating shift work, rather than regular night shift work. The odds ratio of working night shift was found to be 1.24 (OR = 1.24, p = 0.615) higher in breast cancer research participants compared to research participants diagnosed with other types of cancer—odds ratio of 0.80 (p = 0.610). For rotational work, the OR was 1.445, indicating a higher risk than for shift work. It is recommended that the relationship between working night shift and breast cancer risk be explored further through cross-sectional and cohort studies. 展开更多
关键词 BREAST CANCER CANCER NIGHT shift rotating shift Regular NIGHT shift PARITY Genetic PREDISPOSITION
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Factorization of Functional Operators with Involutive Rotation on the Unit Circle
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作者 Aleksandr Karelin Anna Tarasenko 《Applied Mathematics》 2020年第11期1132-1138,共7页
Following the classical definition of factorization of matrix-functions, we introduce a definition of factorization for functional operators with involutive rotation on the unit circle. Partial indices are defined and... Following the classical definition of factorization of matrix-functions, we introduce a definition of factorization for functional operators with involutive rotation on the unit circle. Partial indices are defined and their uniqueness is proven. In previous works, the main research method for the study scalar singular integral operators and Riemann boundary value problems with Carlemann shift were operator identities, which allowed to eliminate shift and to reduce scalar problems to matrix problems without shift. In this study, the operator identities were used for the opposite purpose: to transform operators of multiplication by matrix-functions into scalar operators with Carlemann linear-fractional shift. 展开更多
关键词 Carlemann shift Operator Identities FACTORIZATION Involutive rotation
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面向旋转载体的卫星导航天线相位缠绕问题与分析
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作者 王俊 瞿辰旭 董先哲 《航空兵器》 CSCD 北大核心 2024年第3期66-71,共6页
为解决卫星导航接收机在小口径旋转导弹应用中无法实现载波连续跟踪问题,本文通过分析小口径旋转导弹接收的卫星导航信号特点,研究载体旋转对接收信号幅度和载波相移的影响,建立载体旋转状态下接收信号的幅度变化模型和载波相移模型,提... 为解决卫星导航接收机在小口径旋转导弹应用中无法实现载波连续跟踪问题,本文通过分析小口径旋转导弹接收的卫星导航信号特点,研究载体旋转对接收信号幅度和载波相移的影响,建立载体旋转状态下接收信号的幅度变化模型和载波相移模型,提出了天线相位缠绕会引入额外的载波相移并改进原有的系统模型。依据信号模型进行系统仿真,并搭建了试验环境以证明相位缠绕对载波相位测量引入的误差不可忽略。试验结果表明,本文所改进的相位缠绕系统模型与实测数据均方根误差为11.13°,为卫星导航接收机实现载波跟踪进行精确的相位补偿提供理论依据,进而为提高高速旋转载体卫星导航性能提供理论支撑。 展开更多
关键词 旋转载体 卫星导航 幅度变化模型 载波相移模型 相位缠绕 导弹
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Fundamental Interaction Bridging Elements, in Supplement to the Standard Model
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作者 Christos Tsikoudas Theodore Karacostas 《Journal of Modern Physics》 2024年第12期2023-2168,共146页
An interdisciplinary-field research brings new elements in bridging the gravitational interaction with the Standard Model, by focusing on 3 factors. The involvement of inductive and capacitive-like phase shifts in the... An interdisciplinary-field research brings new elements in bridging the gravitational interaction with the Standard Model, by focusing on 3 factors. The involvement of inductive and capacitive-like phase shifts in the gravitational interaction, the exploration of swapping between parameters of time and space, and the provision of a way to handle imaginary terms. The existence of phase shifts in the gravitational interaction is documented via re-interpretation of older quantitative predictions, and is specifically linked to the Higgs field mechanism. Same as in electronics, a phase shift splits energy into real and imaginary coordinates. This allows to quantitatively treat inertia as an inductive-like potential, alongside the swapping of parameters of time and space. That also allows to treat the Bernoulli pressure in quantitative analogy to a magnetic potential, as well as barrier penetration in quantitative symmetry to the crossing of displacement-current through a capacitor. The findings shed light on how fields & forces, including reaction forces function, while the role of imaginary numbers is analyzed. Interaction of fields with quantum particles is discussed to involve a Fourier-series effect that results in energy quantization. The role of phase shifts becomes essential in bridging between wave nature and effects of relativity, and the Weinberg angle is explained to have the role of an inductive-like shift. The precise value of this angle is proposed to link to elementary particles’ properties like spin, or the value of quarks’ charge. Symmetries introduced allow to address the abundance of matter over antimatter in certain analogy to theory from electronics, to address galaxy rotation curves through an interaction involving negative energy, and more. The new concepts open up room for advancements in energy exploitation over interdisciplinary areas. 展开更多
关键词 Fundamental Interaction Higgs Field Phase shift INERTIA Weinberg Angle Displacement Field Galaxy rotation Negative Energy TOE Framework
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基于双旋转移相变压器的有源配电网多台区同步调压及降损优化策略
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作者 杨鹏 李铁成 +3 位作者 邵晨 苏灿 王向东 孙广辉 《南方电网技术》 CSCD 北大核心 2024年第2期67-76,共10页
针对高比例可再生能源接入导致的配电网电压越限难题,以及现有调压方法难以兼顾双向调压及降损优化功能的问题,提出了一种基于相量合成原理并具有双向调压、可靠性高、成本低特性的串联型双旋转移相变压器(double rotating phase shift ... 针对高比例可再生能源接入导致的配电网电压越限难题,以及现有调压方法难以兼顾双向调压及降损优化功能的问题,提出了一种基于相量合成原理并具有双向调压、可靠性高、成本低特性的串联型双旋转移相变压器(double rotating phase shift transformer,DRPST)调节装置。首先,介绍了DRPST的拓扑结构、工作原理和等效电路,建立了其简化电路模型,在此基础上对电压越限原因进行了分析,构建了包含DRPST的有源配电网模型。其次,提出了基于DRPST的实时滚动双层优化策略,内层模型以电压偏差及线路损耗最小为目标,利用多目标粒子群算法进行了求解,并通过模糊隶属度函数方法确定内层模型Pareto解集最优折衷解,外层模型根据内层模型的最优折衷解,利用双闭环PI调节实现DRPST输出转子角度的无差控制。最后通过MATLAB/Simulink进行了仿真分析,验证了所提拓扑与控制方法的正确性和有效性。 展开更多
关键词 双旋转移相变压器 电压调节 双层规划 有源配电网
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重频可调谐U波段被动谐波锁模光纤激光器
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作者 王明娇 黄千千 +3 位作者 李卫淅 田昊晨 黄梓楠 牟成博 《红外与激光工程》 EI CSCD 北大核心 2024年第8期40-48,共9页
U波段(1 625~1 675 nm)高重频锁模光纤激光器在甲烷气体检测、扩展通信波段、光子显微镜、眼部手术等领域有广泛的应用前景。基于被动谐波锁模(Harmonic Mode-Locking, HML)的孤子自频移(Soliton Self-Frequency Shift, SSFS)技术是一... U波段(1 625~1 675 nm)高重频锁模光纤激光器在甲烷气体检测、扩展通信波段、光子显微镜、眼部手术等领域有广泛的应用前景。基于被动谐波锁模(Harmonic Mode-Locking, HML)的孤子自频移(Soliton Self-Frequency Shift, SSFS)技术是一种实现高重频U波段激光输出的有效方式。首先搭建了基于非线性偏振旋转(Nonlinear Polarization Rotation, NPR)的被动HML光纤激光器,并以此为种子源,通过级联的放大系统将输出功率最高放大至1.7 W。而后将放大的脉冲输入到一段反常色散的色散位移光纤(Dispersion-Shifted Fiber, DSF)中,利用SSFS效应将其中心波长频移至U波段。研究了其中三个重复频率(722.0、941.7、1 224.2 MHz)状态,系统地探究了脉冲重复频率对SSFS的影响。首次使用NPR被动HML光纤激光器作为SSFS效应种子源,实现了波长可覆盖整个U波段范围的GHz脉冲输出。 展开更多
关键词 谐波锁模光纤激光器 U波段 孤子自频移 非线性偏振旋转
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基于坐标系变换的三维声源定位算法 被引量:6
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作者 郑珍珍 冯华君 +2 位作者 沈常宇 丁驰竹 李奇 《浙江大学学报(工学版)》 EI CAS CSCD 北大核心 2008年第2期341-343,共3页
采用基于声达时间差(TDOA)的声源定位技术,给出了一种基于坐标系变换的三维声源定位算法,该算法弥补了以往算法繁琐、计算量大、定位不准确的缺点.将一个人为设定的坐标系转化为特定的坐标系,使得在原坐标系下处于任意位置的4个麦克风... 采用基于声达时间差(TDOA)的声源定位技术,给出了一种基于坐标系变换的三维声源定位算法,该算法弥补了以往算法繁琐、计算量大、定位不准确的缺点.将一个人为设定的坐标系转化为特定的坐标系,使得在原坐标系下处于任意位置的4个麦克风的坐标转化在新坐标系下具有一定自由度的特定3点的坐标和另一任意点的坐标,并在此新坐标系下快速计算出目标声源的坐标,从而确定声源的实际位置.将实际测量的声源位置与算法的计算结果进行比较,结果表明了该算法的有效性和实用性. 展开更多
关键词 声源定位 坐标系变换 平移 旋转
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超重力法脱除变换气中的CO2 被引量:10
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作者 郭锴 李幸辉 +3 位作者 邹海魁 初广文 杨春基 陈建峰 《化工进展》 EI CAS CSCD 北大核心 2008年第7期1070-1073,共4页
用N2和CO2的混合气体模拟变换气,采用苯菲尔溶液为吸收液进行了超重力法脱除CO2的实验研究,考察了反应温度、系统压力、超重力水平、气液比对反应器出口CO2含量的影响。实验结果表明:随着温度的升高和超重力水平的增强,反应器出口CO2含... 用N2和CO2的混合气体模拟变换气,采用苯菲尔溶液为吸收液进行了超重力法脱除CO2的实验研究,考察了反应温度、系统压力、超重力水平、气液比对反应器出口CO2含量的影响。实验结果表明:随着温度的升高和超重力水平的增强,反应器出口CO2含量先降后升;随着压力的升高,反应器出口CO2含量逐渐降低;液体流量一定时,随着气液比的增大,反应器出口CO2含量逐渐升高。 展开更多
关键词 超重力反应器 变换气 脱碳
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方向无关遥感影像的纹理分类算法 被引量:11
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作者 张林 庹红娅 刘允才 《红外与毫米波学报》 SCIE EI CAS CSCD 北大核心 2004年第3期189-192,共4页
首先根据遥感影像空间分辨率较低 ,局部区域内图像纹理变化不大的特点 ,对遥感影像进行合理的分块 ,使得各分块具有单一的主纹理特征 ;然后利用Gabor小波变换提取各图像块的纹理特征向量 ,并通过简单的循环移位算法 ,方便的形成方向无... 首先根据遥感影像空间分辨率较低 ,局部区域内图像纹理变化不大的特点 ,对遥感影像进行合理的分块 ,使得各分块具有单一的主纹理特征 ;然后利用Gabor小波变换提取各图像块的纹理特征向量 ,并通过简单的循环移位算法 ,方便的形成方向无关的纹理特征向量 ;进而引入改进的棋盘距离来描述图像块间的相似度 ,最后使用无监督聚类算法对影像块进行分类 。 展开更多
关键词 方向无关 遥感影像 纹理分类 GABOR小波变换 循环移位 聚类分析
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两相坐标系下链式STATCOM电流跟踪策略 被引量:8
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作者 王松 谈龙成 +3 位作者 李耀华 王平 任洪涛 宋鹏先 《电机与控制学报》 EI CSCD 北大核心 2014年第1期19-25,共7页
针对分相瞬时电流控制的链式静止同步补偿器三相独立控制、参考电压会引入零序分量的特点,提出了两种基于坐标变换的电流跟踪控制方法。方法将链式STATCOM作为一个整体,分别建立其在两相同步旋转坐标系以及两相静止坐标系下的数学模型,... 针对分相瞬时电流控制的链式静止同步补偿器三相独立控制、参考电压会引入零序分量的特点,提出了两种基于坐标变换的电流跟踪控制方法。方法将链式STATCOM作为一个整体,分别建立其在两相同步旋转坐标系以及两相静止坐标系下的数学模型,并采用比例积分控制器跟踪同步旋转坐标系下的直流参考电流,以及采用比例谐振控制器跟踪静止坐标系下的交流参考电流。还给出了基于FPGA的采用双采样策略的载波相移PWM信号的生成方法,该方法能在低采样频率工况下避免功率开关管的额外动作。所提方法适合于数字控制系统实现,仿真与样机实验最终验证了所提出方法具有响应迅速、稳态无误差的特点。 展开更多
关键词 静止同步补偿器 链式变换器 同步旋转坐标系 静止坐标系 载波相移
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基于图元旋转不变性和相位统计信息的LBP算法在纹理分类中的研究 被引量:10
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作者 韩延彬 尹建芹 李金屏 《计算机学报》 EI CSCD 北大核心 2011年第3期583-592,共10页
传统的LBP算法缺少对图元的相位分析,因此不能较好地区分由图元旋转形成的同类纹理图像.文中提出了一种融合图元旋转不变性和相位统计信息的纹理分析算法.新算法利用图元旋转不变性的等价类约简纹理特征,减小纹理旋转带来的分类误差,然... 传统的LBP算法缺少对图元的相位分析,因此不能较好地区分由图元旋转形成的同类纹理图像.文中提出了一种融合图元旋转不变性和相位统计信息的纹理分析算法.新算法利用图元旋转不变性的等价类约简纹理特征,减小纹理旋转带来的分类误差,然后利用图元的统计相位特征进一步划分纹理图像分类集,进而解决由旋转不变性带来的欠分类问题.该算法选用均值漂移作为纹理分类工具,并采用Brodatz纹理库作测试.与传统的WTGGD、LBP等算法相比,分类效果有显著的改善. 展开更多
关键词 纹理分类 局部二值模式 旋转不变性 相位信息 均值漂移
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并联Roberts柔性机构及其微定位平台的结构与位移分析 被引量:6
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作者 贺磊 吉晓民 +1 位作者 杨先海 王红梅 《机械强度》 CAS CSCD 北大核心 2015年第6期1057-1063,共7页
分析了平行四杆柔性机构与并联Roberts柔性机构的伪刚体模型,并对其耦合位移进行了定性比较;利用闭环矢量法确定了Roberts机构特征点位置;建立了考虑轴漂的位移计算模型,与有限元仿真值相比该模型的最大相对误差仅为2.43%;将对称布置的... 分析了平行四杆柔性机构与并联Roberts柔性机构的伪刚体模型,并对其耦合位移进行了定性比较;利用闭环矢量法确定了Roberts机构特征点位置;建立了考虑轴漂的位移计算模型,与有限元仿真值相比该模型的最大相对误差仅为2.43%;将对称布置的并联Roberts柔铰机构应用于微定位平台,提出了一种3-PRR微动平台新结构,利用功能转化原理建立了整体机构的输入输出关系矩阵,并与试验结果作了对比,结果表明绕z轴转角的最大误差为5.60%。 展开更多
关键词 Roberts柔性机构 轴漂 有限元 微动平台
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基于同步旋转坐标系的有源电力滤波器控制延时动态预测补偿策略 被引量:15
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作者 许胜 费树岷 +1 位作者 赵剑锋 黄允凯 《电工技术学报》 EI CSCD 北大核心 2016年第12期161-169,共9页
提出一种基于同步旋转坐标系(SRF)的有源电力滤波器(APF)控制延时动态预测补偿策略。该方法通过对各次SRF的相移控制,实现对APF各次谐波电流控制延时的补偿;同时,根据微变线性化原理,对SRF上暂态变化的同步谐波电流进行线性预测,从而实... 提出一种基于同步旋转坐标系(SRF)的有源电力滤波器(APF)控制延时动态预测补偿策略。该方法通过对各次SRF的相移控制,实现对APF各次谐波电流控制延时的补偿;同时,根据微变线性化原理,对SRF上暂态变化的同步谐波电流进行线性预测,从而实现对各次谐波电流控制延时的动态预测补偿。首先详细分析了APF控制延时的形成机理、对系统的影响以及延时抑制方法,在此基础上,重点论述所提控制延时动态预测补偿方法,并对基于该方法的APF控制系统进行分析设计。理论分析和实验结果表明,该方法能够实时响应负载暂态变化,精确补偿控制延时,有效提高谐波电流补偿的准确度。 展开更多
关键词 有源电力滤波器 控制延时 同步旋转坐标系相移控制 线性预测补偿
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