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横向联邦学习中差分隐私聚类算法

计算机应用 2024年第1期44卷 217-222页

作者：徐雪冉杨庚黄喻先南京邮电大学计算机学院、软件学院、网络空间安全学院南京210023 江苏省大数据安全与智能处理重点实验室南京210023

聚类分析能够挖掘出数据间隐藏的内在联系并对数据进行多指标划分,从而促进个性化和精细化运营。然而,数据孤岛造成的数据碎片化和孤立化严重影响了聚类分析的应用效果。为了解决数据孤岛问题的同时保护相关数据隐私,提出本地均分扰动联... 详细信息

聚类分析能够挖掘出数据间隐藏的内在联系并对数据进行多指标划分,从而促进个性化和精细化运营。然而,数据孤岛造成的数据碎片化和孤立化严重影响了聚类分析的应用效果。为了解决数据孤岛问题的同时保护相关数据隐私,提出本地均分扰动联邦K-means算法(ELFedKmeans)。针对横向联邦学习模式,设计了一种基于网格的初始簇心选择方法和一种隐私预算分配方案。在ELFedKmeans算法中,各站点联合协商随机种子,以较小的通信代价生成相同的随机噪声,保护了本地数据的隐私。通过理论分析证明了该算法满足差分隐私保护,并将该算法与本地差分隐私K-means(LDPKmeans)算法和混合型隐私保护K-means(HPKmeans)算法在不同的数据集上进行了对比实验分析。实验结果表明,随着隐私预算不断增大,三个算法的F-measure值均逐渐升高;误差平方和(SSE)均逐渐减小。从整体上看,ELFedKmeans算法的F-measure值比LDPKmeans算法和HPKmeans算法分别高了1.7945%~57.0663%和21.2452%~132.0488%;ELFedKmeans算法的Log(SSE)值比LDPKmeans算法和HPKmeans算法分别减少了1.2042%~12.8946%和5.6175%~27.5752%。在相同的隐私预算下,ELFedKmeans算法在聚类质量和可用性指标上优于对比算法。

关键词：横向联邦聚类差分隐私本地扰动可用性 K-means算法

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医学生全周期课程思政教学实践研究

中国高等医学教育 2024年第4期 55-57页

作者：耿阳周颖复旦大学公共卫生学院上海200032

以卫生化学课程为例,构建全周期思政教学体系,包括建立本课程思政元素案例库,结合专业教学开展多层次多渠道的主动式思政学习。并通过问卷调查分析其效果,为提高医学生课程思政教学实效提供新思路。

关键词：课程思政医学生全周期课程思政元素案例库

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工艺非球形颗粒在呼吸道内沉积的动力学特性

中国环境科学 2024年第1期44卷 520-527页

作者：庄加玮陈庚阳杨如梦郭张辉刘恩海刁永发沈恒根常州大学城市建设学院江苏常州213164 东华大学环境科学与工程学院上海201620 常州大学石油与天然气工程学院、能源学院江苏常州213164

为探明铸造车间内非球形颗粒在工人呼吸道内沉积的动力学特性,借助电镜扫描获得粉尘颗粒的微观形貌,通过数值模拟方法分析5种形状颗粒在G3~G6及G9~G12呼吸道内运动规律,并讨论颗粒形状、呼吸量、颗粒粒径对其沉积分布的影响.结果表明,... 详细信息

为探明铸造车间内非球形颗粒在工人呼吸道内沉积的动力学特性,借助电镜扫描获得粉尘颗粒的微观形貌,通过数值模拟方法分析5种形状颗粒在G3~G6及G9~G12呼吸道内运动规律,并讨论颗粒形状、呼吸量、颗粒粒径对其沉积分布的影响.结果表明,颗粒的形状因子φ越大、粒径越大、呼气量越大,非球形颗粒在呼吸道内沉积率ηt越高;φ越小,非球形颗粒在G3~G6呼吸道内沉积分布越分散,在G9~G12呼吸道内则相反;非球形颗粒在G3~G6呼吸道内主要因惯性碰撞发生沉积,φ越小的颗粒受到的曳力作用越强,不同形状颗粒间沉积率差异明显胜于其在G9~G12呼吸道,局部沉积率差异更是超过了30%.因此,形状因子小的非球形颗粒更易被输运至呼吸道较深的位置,对工人的健康威胁可能性更大.

关键词：职业卫生呼吸道铸造车间颗粒形状沉积率数值模拟

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瓶装材料对核桃油品质及预测货架期的影响

粮油食品科技 2024年第4期32卷 169-177页

作者：胡伯凯税会霞耿阳阳李学琴曾亚军杨光贵州省林业科学研究院贵州省核桃研究所贵州省核桃工程技术研究中心贵州贵阳550005 贵阳信息科技学院贵州贵阳550025 贵州阳光食品有限公司贵州毕节551600

为探究不同瓶装材料对核桃油品质变化的影响,分别用敞口玻璃烧杯、马口铁罐、玻璃油瓶盛装核桃油,采用Schaal烘箱法加速油脂氧化,以过氧化值、酸值、脂肪酸组成、驰豫特性为评价指标,研究不同瓶装材料对核桃油氧化稳定性及预测货架期的... 详细信息

为探究不同瓶装材料对核桃油品质变化的影响,分别用敞口玻璃烧杯、马口铁罐、玻璃油瓶盛装核桃油,采用Schaal烘箱法加速油脂氧化,以过氧化值、酸值、脂肪酸组成、驰豫特性为评价指标,研究不同瓶装材料对核桃油氧化稳定性及预测货架期的影响。结果表明,以过氧化值≤0.25 g/100 g为限量值时(植物油国家标准规定),添加特丁基对苯二酚(TBHQ)的烧杯、马口铁罐、玻璃油瓶盛装核桃油和空白对照的预测货架期分别为160、112、336和64 d,在预测货架期内,核桃油酸价均在二级核桃油要求范围内。3种包装材料对添加TBHQ的核桃油氧化稳定性强弱顺序为:玻璃油瓶>烧杯>马口铁罐;核桃油长期贮藏建议以玻璃油瓶盛装为佳。

关键词：核桃油瓶装材料预测货架期氧化稳定性

Fault ride-through of renewable energy conversion systems during voltage recovery

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Journal of Modern Power Systems and Clean Energy 2016年第1期4卷 28-39页

作者： Ruiqi LI Hua geng geng yang Department of Automation Tsinghua UniversityBeijing 100084China

Asymmetrical voltage swells during recovery of a short-circuit fault lead to fluctuations in the dc-link voltage of a renewable energy conversion system(RECS),and may induce reversed power flow and even trip the RECS. This paper studies characteristics of both typical causes resulting in the practical asymmetrical voltage swell and the voltage at the point of common coupling(PCC)during the fault recovery. As analyzed, the fault recovery process can be divided into two continuous periods in which different control strategies have to be applied. Also protective measures are necessary in the transient period of the process. Additionally, the asymmetrical high-voltage ride-through capability and the controllability criteria of the RECS are analyzed based on eliminating the fluctuations. Furthermore, an asymmetrical control scheme is proposed to maintain the controllability of the RECS and ride through the entire recovery process. As verified by the simulation, the scheme can promise the RECS to deal with the practical fault recovery period and mitigate the dc-link voltage fluctuations, which improves the reliability of the RECS and the power system.

关键词： Inverter Renewable energy conversion system Asymmetrical grid voltage High-voltage ride-through(HVRT) Limit analysis

Phillips-Heffron model for current-controlled power electronic generation unit

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Journal of Modern Power Systems and Clean Energy 2018年第3期6卷 582-594页

作者： Shulong TAN Hua geng geng yang Department of Automation Tsinghua University

This paper presents a Phillips-Heffron model for the generation unit with current-controlled(CC) voltage source converter(VSC) as the interface. A concept of current angle is put forward for the CC-VSC, and the relationship between the current angle and the power angle is also quantified. Based on the current angle, a PhillipsHeffron model is established for the generation unit with CC-VSC, considering the dynamic of phase-locked-loop(PLL) in the weak grid. The model demonstrates that small-signal dynamics of the generation unit is similar to that of the traditional synchronous generator(SG) which is characterized by the electromechanical swing *** the dynamics can be depicted by the famous inertia,synchronizing and damping coefficients. Small-signal stability of a CC-VSC-based single machine infinite bus system is analyzed by means of the traditional theory of power system. Based on the relationship between the current angle and the power angle, the Phillips-Heffron model of the CC-VSC is also used in stability analysis of multimachine power system, and parameter optimizations of the CC-VSC are also studied for stability improvement.

关键词： Phillips-Heffron model Voltage source converter Current angle Synchronous generator Small-signal stability

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不同菌材栽培糙皮侧耳营养品质综合评价

食品安全质量检测学报 2024年第9期15卷 321-331页

作者：张时馨陈荟耿阳阳贵州省核桃研究所贵阳550005 贵州省林业科学研究院西南喀斯特山地生物多样性保护国家林业和草原局重点实验室贵阳550005 贵州省云关山国有林场贵阳550005

目的分析不同菌材栽培糙皮侧耳(Pleurotus ostreatus)生长及营养品质差异,并对其营养品质进行综合评价。方法以贵州5种常见菌材锥栗(Castanea henryi)、构树(Broussonetia papyrifera)、刺槐(Robinia pseudoacacia)、光皮桦(Betula luminifera)、青冈(Quercus glauca)为主要培养料栽培糙皮侧耳,对糙皮侧耳菌丝生长、子实体主要农艺性状及营养品质进行分析。结果糙皮侧耳在光皮桦培养基上菌丝生长速率更快,在锥栗和刺槐栽培基质中子实体主要农艺性状更好。刺槐栽培基质中糙皮侧耳子实体粗蛋白、Cu、Zn、K元素含量最高,锥栗栽培基质中糙皮侧耳子实体多糖、Na、Mg、Fe、Ca元素含量最高。以5种菌材栽培的糙皮侧耳子实体总氨基酸、必需氨基酸含量为刺槐>青冈>光皮桦>构树>锥栗,总药用氨基酸含量为青冈>刺槐>光皮桦>构树>锥栗。5种菌材栽培的糙皮侧耳子实体呈味氨基酸主要为甜味和苦味氨基酸,其中光皮桦栽培的糙皮侧耳子实体鲜甜味更佳。必需氨基酸营养品质评价及营养品质综合评价结果表明刺槐栽培糙皮侧耳子实体综合营养品质更好。Fe、苏氨酸、丙氨酸、谷氨酸、精氨酸、天冬氨酸、组氨酸、Zn和多糖是5种菌材栽培的糙皮侧耳子实体主要差异营养成分。相关性分析结果显示菌材营养成分主要与糙皮侧耳菌丝生长、子实体主要农艺性状和矿物质元素含量显著相关。结论不同营养成分的菌材对糙皮侧耳子实体生长和营养品质的影响不同,刺槐更适合作为生产糙皮侧耳主栽菌材。

关键词：糙皮侧耳菌材营养品质氨基酸相关性

Numerical simulation of shock wave phenomena in hydrodynamic model of semiconductor devices

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The Journal of China Universities of Posts and Telecommunications 2007年第1期14卷 71-76页

作者： XU Ning yang geng College of Optical and Electric Engineering Nanjjing University of Posts and Telecommunications Nanjing 210003 China College of Mathematics and Physics Nanking University of Posts and Telecommunications Nanjing 210003 China

We propose a finite element method to investigate the phenomena of shock wave and to simulate the hydrodynamic model in semiconductor devices. An introduction of this model is discussed first. Then some scaling factors and a relationship between the changing variables are discussed. And then, we use a finite element method （P1-iso-P2 element） to discrete the equations. Some boundary conditions are also discussed. Finally, a sub-micron n%＋-n-n^＋ silicon diode and Si MESFET device are simulated and the results are analyzed. Numerical results show that electronic fluids are transonic under some conditions.

关键词： hydrodynamic model semiconductor devices finite element method shock wave

Near-optimal cumulative longitude low-thrust orbit transfer

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Journal of Systems Engineering and Electronics 2009年第6期20卷 1271-1277页

作者： Yue Xincheng yang Ying geng Zhiyong State Key Lab. for Turbulence and Complex System Dept. of Mechanics and Aerospace Engineering Coll. of Engineering Peking Univ. Beijing 100871 P. R. China

The indirect method for the continuous low-thrust near minimum cumulative longitude orbit transfer problem is *** movement of the satellite is described by the Gauss equation using the modified equinoctial elements and replacing time as the system independent variable by the cumulative *** maximum principle is adapted to design the optimal control in order to minimize the final cumulative longitude, and the twopoint-boundary-value problem is derived from the orbit transfer *** single shooting method is applied in a numerical experiment, and the simulations demonstrate that the orbit transfer mission is fulfilled and the product of the maximal thrust and the minimum cumulative longitude is near constant.

关键词： minimum cumulative longitude orbit transfer continuous thrust maximum principle shooting method.