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Applicability of Sigmoid Colon Graft for Vaginal Replacement (Colovaginoplasty) at Young Age
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作者 Mohamed A. Baky Fahmy Hanaa Abdel Hamid M. Al Abeissy Mohamed M. Abdalla 《Surgical Science》 2011年第8期422-426,共5页
Objective: - To evaluate the applicability, feasibility, complications, short and long term results of vaginoplasty by using sigmoid colon graft with stapler assistance for resuming colonic continuity in children with... Objective: - To evaluate the applicability, feasibility, complications, short and long term results of vaginoplasty by using sigmoid colon graft with stapler assistance for resuming colonic continuity in children with absent vagina. Patients and Methods: - Records of 15 patients 8 of them had Androgen Insensitivity Syndrome, 4 had congenital vaginal atresia, and 3 had Congenital Adrenal Hyperplasia, underwent sigmoid graft vaginal reconstruction with the aid of circular stapler during the period from 2005 to 2010 were reviewed retrospectively. Results: A neovagina was constructed in those patients who aged from 3 to 9 years (mean 4 years), where sigmoid colon was used in all patients. Hospital stay ranged from 5 to 12 days (mean 7), operative time ranged from 60 to 120 min (mean 75 min). All patients were followed up 6 monthly in the first year and then yearly, complications occurred in 4 patients: introital stenosis in 2, and another 2 cases had minor wound infection. The need for neovaginal dilation was indicated in 5 out of 15 patients. There was no complications related to bowel anastomosis, No mortality in this group and the cosmetic results were excellent in all cases. Conclusion: Sigmoid colovaginoplasty appears to be applicable for remedy of vaginal atresia at any age. It is associated with a less complication rate, the long term results is satisfactory and it seems a better technique, especially in girls who doesn’t expect sexual activity shortly after surgery. 展开更多
关键词 VAGINAL REPLACEMENT VAGINAL ATRESIA STAPLER Neovagina Colovaginoplasty and sigmoid GRAFT
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基于sigmoid滤波器的永磁轮毂电机自抗扰控制
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作者 全力 刘诗龙 +4 位作者 朱孝勇 张超 杜怿 徐磊 张丽 《农业工程学报》 EI CAS CSCD 北大核心 2024年第10期14-23,共10页
相比燃油拖拉机,电动拖拉机具有节能高效、绿色清洁的优点。分布式驱动电动拖拉机结构简单、控制维度多,能进一步提高电动拖拉机的工作效率和作业精度。但是电机检测转速噪声导致轮毂电机速度波动严重,复杂路面及多种作业工况下进一步... 相比燃油拖拉机,电动拖拉机具有节能高效、绿色清洁的优点。分布式驱动电动拖拉机结构简单、控制维度多,能进一步提高电动拖拉机的工作效率和作业精度。但是电机检测转速噪声导致轮毂电机速度波动严重,复杂路面及多种作业工况下进一步加剧了上述问题,严重降低了拖拉机的作业质量。针对上述问题,该研究提出一种基于sigmoid滤波器的线性自抗扰控制(linear active disturbance rejection control,LADRC)以提高轮毂电机的转速稳定性和抗扰动能力。该控制策略在传统LADRC的基础上引入sigmoid滤波器至扩张状态观测器(extended state observer,ESO),根据输入噪声信号误差变化改变滤波器带宽,以抑制观测误差中的中高频干扰信号,同时避免滤波器积分环节对轮毂电机速度跟踪快速性的影响,具有较快的收敛性。搭建试验平台对所提出控制策略进行试验验证,结果表明:与传统LADRC策略相比,本文所提控制策略在变速和变载工况下的转速脉动分别减小了32%和41.67%,iq电流脉动分别减小了6.25%和4.17%,可在快速、准确跟踪给定转速的同时,大幅提高轮毂电机驱动系统的噪声抑制性能,为复杂环境下电动拖拉机高精度作业提供技术参考。 展开更多
关键词 永磁电机 噪声 线性自抗扰控制 扩张状态观测器 sigmoid滤波器
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基于AHP耦合Sigmoid函数的重载铁路黄土边坡风险分析
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作者 李浩然 李铮 +3 位作者 马遥 卓崔瑶 周通 赵志荣 《铁道标准设计》 北大核心 2024年第7期48-52,91,共6页
重载铁路具有大轴重、高密度、大运量的运输特点,黄土边坡路基段一直是重载铁路运营的高风险区段,现有风险评价方法尚无法满足其风险量化分析的需求。利用层次分析法AHP耦合Sigmoid函数的方法,围绕事故发生概率和损失两个方面对重载铁... 重载铁路具有大轴重、高密度、大运量的运输特点,黄土边坡路基段一直是重载铁路运营的高风险区段,现有风险评价方法尚无法满足其风险量化分析的需求。利用层次分析法AHP耦合Sigmoid函数的方法,围绕事故发生概率和损失两个方面对重载铁路黄土边坡工程展开风险定量评价。首先以边坡滑塌事故调研和稳定性控制理论为基础,明确黄土边坡的失稳影响因素,建立重载铁路黄土边坡稳定性评价模型和边坡失稳危害性评价模型;然后应用层次分析法建立黄土边坡稳定性评价模型指标权重,并提出各级影响因素的指标赋值方法;而后引入基于朴素贝叶斯理论的Sigmoid函数,构建边坡稳定服役概率、风险判断矩阵和黄土边坡的风险等级确定方法;最后以朔黄铁路某站高陡黄土边坡为工程背景,应用所得理论方法对其进行风险定量分析,计算得出该边坡失稳概率为0.64,造成经济损失约8611万元,隶属于高风险等级,并针对坡体几何特征、渗透能力、基岩特性等低分指标提出了具体的安全性提升措施建议。 展开更多
关键词 重载铁路 风险分析 层次分析法 sigmoid函数 经济损失
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Microscopic Structure of the Sigmoido-Jugular Junction in the Third-Trimester Fetus
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作者 Léon Boukassa Ruth Ibara Wame +3 位作者 Bejart Evayoulou-Kouamvi Fabien Gaël Mouamba Oldany Lizen Mozoma Eloge Mbongo Backobi 《Open Journal of Modern Neurosurgery》 2024年第4期267-274,共8页
Context and Justification: The sigmoido-jugular junction connects two structures of different compositions and has a complex organization. The sinusoidal portion of its endothelium contains muscle cells in adults. Is ... Context and Justification: The sigmoido-jugular junction connects two structures of different compositions and has a complex organization. The sinusoidal portion of its endothelium contains muscle cells in adults. Is this the same presentation observed in fetuses? Objective: To describe the sigmoido-jugular junction in fetuses. Materials and Methods: Over a period of seven months, a histochemical and immunohistochemical study was conducted on 30 sigmoido-jugular junctions taken from 15 fetuses aged at least 32 weeks of gestation. These fetuses were obtained following expulsion due to intrauterine death, after informed consent from the parents. Results: Three portions can be identified: sigmoid, junctional, and jugular. Histochemical preparations revealed the existence of two constant layers and a third layer present only at the jugular level. From the inside out, the layers are as follows: 1) Inner Layer (Endothelium): This layer is clearer from the junction and reveals the presence of smooth muscle cells at the sigmoid level in immunohistochemistry. 2) Outer Layer: At the sigmoid and junctional levels, this layer consists of collagen fibers and becomes median at the jugular level, where it is composed of elastic and muscular collagen fibers. 3) Third Layer: Present only at the jugular level, this layer corresponds to the adventitia. Conclusion: The architecture of the sigmoido-jugular junction in fetuses, which is identical to that in adults, excludes the metaplastic hypothesis regarding endothelial smooth muscle cells in the sigmoid portion. Instead, it favors their role in regulating encephalic venous drainage. 展开更多
关键词 sigmoido-Jugular Junction Venous Drainage sigmoid Endothelium Smooth Muscle Cells
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基于Sigmoid函数的非对称式S型曲线机械臂加减速控制方法
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作者 杨传光 费胜巍 《东华大学学报(自然科学版)》 CAS 北大核心 2024年第5期118-126,共9页
机械臂广泛应用于制造、装配、搬运、码垛等方面,对提高生产力起着重要作用。为减小机械臂在运动过程中的振动和冲击,提高机械臂轨迹执行效率,提出一种非对称式S型曲线加减速控制方法。该方法通过在双段Sigmoid函数中插入直线段,构成加... 机械臂广泛应用于制造、装配、搬运、码垛等方面,对提高生产力起着重要作用。为减小机械臂在运动过程中的振动和冲击,提高机械臂轨迹执行效率,提出一种非对称式S型曲线加减速控制方法。该方法通过在双段Sigmoid函数中插入直线段,构成加加速度连续的运动学曲线。通过粒子群算法进行参数优化求解,无需反复确认每个时间段的存在性即可求出非对称约束下的曲线参数,并分别在关节空间和笛卡尔空间采用时间同步和位移同步方法使机械臂的运动轨迹更加协调自然。结果表明,相同条件下提出的方法比三角函数方法轨迹执行效率更高且加加速度仅为三角函数方法的55%。与梯形加加速度曲线相比,采用提出的方法规划的运动轨迹可减少35.7%的残余振动,验证了该方法的有效性。 展开更多
关键词 机械臂 非对称式S型曲线 轨迹规划 sigmoid函数
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一种Sigmoid为激活函数的高精度ANN电路的设计
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作者 何从蓉 邢世威 吴晨健 《电子器件》 CAS 2024年第3期617-622,共6页
提出了一款以Sigmoid为激活函数的人工神经网络(ANN)电路,实现对目标数据的分类,基于TSMC 180 nm CMOS工艺完成了电路设计、版图设计、仿真与流片测试,芯片面积为0.3375 mm^(2),1.8 V电源电压下电路功耗为216μW。3块芯片的测试结果显示... 提出了一款以Sigmoid为激活函数的人工神经网络(ANN)电路,实现对目标数据的分类,基于TSMC 180 nm CMOS工艺完成了电路设计、版图设计、仿真与流片测试,芯片面积为0.3375 mm^(2),1.8 V电源电压下电路功耗为216μW。3块芯片的测试结果显示,电路对目标数据的分类准确率为97.5%,误差在(-3.2%,3.27%)之间,平均误差为-1.51%。人工神经网络电路含有3个网络层,由15个Sigmoid激活函数神经元电路组成,两输入Sigmoid激活函数神经元电路由两个加权电路与一个Sigmoid激活函数电路组成。后仿真结果显示,在1.8 V电源电压下,神经元电路的功耗为8.02μW,最大噪声为√Hz,版图面积为0.001 mm^(2),最大相对误差为1.76%。 展开更多
关键词 sigmoid神经元电路 CMOS 人工神经网络电路
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脉冲噪声下基于Sigmoid的LFM信号参数估计
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作者 王厚友 郭勇 杨立东 《电子测量技术》 北大核心 2024年第2期176-184,共9页
由于脉冲噪声具有的短时大幅值特性,使得基于高斯假设的信号参数估计方法无法在脉冲噪声环境下有效估计参数。针对此问题,利用α稳定分布模拟随机脉冲噪声,提出了一种基于Sigmoid-CFRFT的LFM信号参数估计方法。首先,建立了一种自适应Sig... 由于脉冲噪声具有的短时大幅值特性,使得基于高斯假设的信号参数估计方法无法在脉冲噪声环境下有效估计参数。针对此问题,利用α稳定分布模拟随机脉冲噪声,提出了一种基于Sigmoid-CFRFT的LFM信号参数估计方法。首先,建立了一种自适应Sigmoid函数,证明了信号经过此非线性变换后,信号的2阶矩由无界变为有界,且信号的相位信息保持不变。其次,将变换后的信号进行离散时间CFRFT,建立了数学优化模型,并使用水循环算法搜索最优值点。最后,利用了非标准SαS分布噪声的修正方法,分析了标准和非标准分布下参数估计的性能。仿真结果说明,所提方法不仅可以有效抑制脉冲噪声对LFM信号分数谱特征的影响,而且能够实现低信噪比信号参数的高精度估计。相比于现有的基于非线性变换的参数估计方法,本文方法具有更好的精度,稳定性和噪声鲁棒性。 展开更多
关键词 线性调频信号 sigmoid函数 简明分数阶傅里叶变换 脉冲噪声 参数估计
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基于用户响应意愿度三维Sigmoid云模型的电动汽车优化调度策略
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作者 葛晓琳 胡文哲 +1 位作者 符杨 曹士鹏 《中国电机工程学报》 EI CSCD 北大核心 2024年第22期8874-8883,I0015,共11页
电动汽车(electric vehicle,EV)车主响应调度的意愿存在较大的不确定性,这给电动汽车的优化调度带来巨大的挑战。为此,该文提出一种基于用户响应意愿度三维Sigmoid云模型的分时段EV优化调度策略。首先,根据Hampel准则分析各历史日EV充... 电动汽车(electric vehicle,EV)车主响应调度的意愿存在较大的不确定性,这给电动汽车的优化调度带来巨大的挑战。为此,该文提出一种基于用户响应意愿度三维Sigmoid云模型的分时段EV优化调度策略。首先,根据Hampel准则分析各历史日EV充电负荷概率密度函数间的Copula熵辨识出历史相关日,以强相关日的出行概率分布经BP神经网络预测车辆的停驻时间和荷电状态概率分布;其次,为描述受多重因素影响下EV用户的响应意愿,建立三维Sigmoid云模型从而刻画EV用户的价格收益和时间裕度对响应意愿的不确定映射关系;最后,基于响应意愿灵敏度将不同的响应意愿剥离后对应至相应的充电调度区间,以最小化配电网的负荷波动和调度费用为目标对EV进行分时段优化调度。仿真结果表明,相比传统方法,所提三维Sigmoid云模型量化了EV响应行为的不确定性,均方根误差减小约35%,在满足用户用车需要和响应意愿的同时使配电网负荷波动率降低11.28%。 展开更多
关键词 电动汽车 sigmoid云模型 优化调度 响应意愿
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Adult sigmoid intussusception resembling rectal prolapse:A case report
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作者 Tsung-Jung Tsai Yu Shih Liu 《World Journal of Clinical Cases》 SCIE 2024年第6期1163-1168,共6页
BACKGROUND Rectal prolapse arises from benign etiology.When symptoms of internal intussusception mirror those of rectal prolapse,a misdiagnosis is possible,especially under limited clinical presentation.It is crucial ... BACKGROUND Rectal prolapse arises from benign etiology.When symptoms of internal intussusception mirror those of rectal prolapse,a misdiagnosis is possible,especially under limited clinical presentation.It is crucial to recognize and differentiate rectal prolapse from internal intussusception because the two diagnoses have different prognoses.Here,we describe a case of adult sigmoid intussusception presenting as rectal prolapse.CASE SUMMARY A 64-year-old woman with no known medical history visited a gastrointestinal outpatient department due to hard bloody stool defecation for 1 wk followed by constipation for 3 d.Colonoscopy revealed a huge polypoid ulcerated tumor at the sigmoid colon with lumen stenosis.The patient was admitted due to postprocedural dull abdominal pain.Due to failed colonoscopy reduction and stent insertion,the patient underwent sigmoid colon resection with primary end-to-end anastomosis,with the transverse colostomy pathological report showing adenocarcinoma,pT3N0M0.She recovered well from the operation and was discharged with regular outpatient clinic follow-up.CONCLUSION Presentation and manifestation of sigmoid intussusception may resemble that of rectal prolapse,necessitating careful observation due to distinct prognostic implications. 展开更多
关键词 sigmoid intussusception Rectal prolapse Endoscopic reduction ADENOCARCINOMA Case report
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Comprehensive evaluation of rare case:From diagnosis to treatment of a sigmoid Schwannoma:A case report
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作者 Jing-Yi Li Xi-Zhuang Gao +3 位作者 Jian Zhang Xiang-Zheng Meng Yi-Xian Cao Kun Zhao 《World Journal of Gastrointestinal Oncology》 SCIE 2024年第1期244-250,共7页
BACKGROUND Schwannomas are uncommon tumors originating from Schwann cells,forming the neural sheath.They account for approximately 2%-6%of all mesenchymal tumors and are most commonly identified in peripheral nerve tr... BACKGROUND Schwannomas are uncommon tumors originating from Schwann cells,forming the neural sheath.They account for approximately 2%-6%of all mesenchymal tumors and are most commonly identified in peripheral nerve trunks,with rarity in the gastrointestinal tract.Among gastrointestinal locations,the stomach harbors the majority of nerve sheath tumors,while such occurrences in the sigmoid colon are exceptionally infrequent.CASE SUMMARY This study presented a clinical case involving a 60-year-old female patient who,during colonoscopy,was diagnosed with a submucosal lesion that was later identified as a nerve sheath tumor.The patient underwent surgical resection,and the diagnosis was confirmed through immunohistochemistry.This study highlighted an exceptionally uncommon occurrence of a nerve sheath tumor in the sigmoid colon,which was effectively managed within our department.Additionally,a comprehensive review of relevant studies was conducted.CONCLUSION The preoperative diagnosis of nerve sheath tumors poses challenges,as the definitive diagnosis still relies on pathology and immunohistochemistry.Although categorized as benign,these tumors have the potential to demonstrate malignant behavior.Consequently,the optimal treatment approach entails the complete surgical excision of the tumor,ensuring the absence of residual lesions at the margins. 展开更多
关键词 SCHWANNOMA Gastrointestinal stromal tumors TREATMENT sigmoid colon Case report
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Aggressive fibromatosis of the sigmoid colon:A case report
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作者 Pan-Pan Yu Xin-Chun Liu +1 位作者 Lu Yin Guang Yin 《World Journal of Gastrointestinal Oncology》 SCIE 2024年第8期3716-3722,共7页
BACKGROUND Aggressive fibromatosis(AF),also known as desmoid tumor or desmoid-type fibromatosis,is a rare soft tissue neoplasm that can occur in almost any part of the body.Although it is a benign disease,AF is aggres... BACKGROUND Aggressive fibromatosis(AF),also known as desmoid tumor or desmoid-type fibromatosis,is a rare soft tissue neoplasm that can occur in almost any part of the body.Although it is a benign disease,AF is aggressive and infiltrative and has a high recurrence rate after surgery.Common sites for intra-abdominal AF are the small bowel mesentery,retroperitoneum,and pelvis.AF in the colon is extremely rare.CASE SUMMARY Here,we report the first case of sigmoid colon AF,which was accidentally discovered in a 27-year-old woman during laparoscopic myomectomy.Computed tomography confirmed a slightly enhanced mass in the sigmoid colon.Subsequent colonoscopy did not reveal a mass in the colonic lumen,but a suspected external compress was found in the sigmoid colon.Surgical disease involving a gastrointestinal stromal tumor was suspected.The patient underwent laparoscopic exploration,and sigmoidectomy with a negative margin was performed to excise the mass.Postoperative immunohistochemistry revealed that the mass was an AF.The patient recovered well and was recurrence-free at the 30-month follow-up without adjuvant therapy.CONCLUSION AF should be considered in the differential diagnosis of subepithelial colon masses.Radical resection alone can achieve good outcomes. 展开更多
关键词 Aggressive fibromatosis Desmoid tumor sigmoid mass Subepithelial tumor Case report
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Unexpected right-sided sigmoid colon in laparoscopy: A case report and review of literature
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作者 Shi-Fu Hu Xiang-Yu Liu +1 位作者 Han-Bo Liu Yuan-Yuan Hao 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第11期3606-3613,共8页
BACKGROUND The presence of a right-sided sigmoid colon is a rare anatomical variation usually discovered incidentally during surgical interventions.This case report details an unexpected right-sided sigmoid colon iden... BACKGROUND The presence of a right-sided sigmoid colon is a rare anatomical variation usually discovered incidentally during surgical interventions.This case report details an unexpected right-sided sigmoid colon identified during a laparoscopic appendectomy and examines the pertinent literature to explore its clinical importance.CASE SUMMARY A 71-year-old woman presented with acute appendicitis.A preoperative computed tomography(CT)scan showed peri-appendiceal inflammation but no significant anatomical abnormalities.During laparoscopic surgery,an unexpected finding was encountered:The sigmoid colon was situated on the right side and exhibited an abnormal relationship with the cecum and ascending colon.Postoperative pathological examination confirmed appendicitis with no additional pathological findings.The right-sided sigmoid colon anomaly was verified through intraoperative assessment and later re-evaluation with CT and colonographic imaging.The patient underwent a laparoscopic appendectomy and experienced a smooth postoperative recovery.CONCLUSION This case highlights the necessity of being attentive to anatomical variations during laparoscopic surgery,particularly when managing appendicitis.A review of the literature indicated that the occurrence of a right-sided sigmoid colon is infrequent and may be associated with anomalies in midgut rotation during embryonic development.Awareness of this variation can help prevent surgical complications and inform future clinical practice. 展开更多
关键词 Right-sided sigmoid colon LAPAROSCOPY Anatomical variation Literature review Surgical implications Case report
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基于改进型sigmoid函数的混合储能系统SOC控制策略
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作者 毛阗 徐鉴其 靳媛 《建筑电气》 2024年第S01期55-61,共7页
介绍锂离子电池-超级电容混合储能系统的传统SOC控制策略,提出一种基于改进型sigmoid函数的SOC控制策略,并通过算例来展示混合储能模型的构建、仿真过程,分析验证基于改进型sigmoid函数的混合储能系统SOC控制策略的有效性。
关键词 改进型sigmoid函数 建筑主动配电系统 混合储能 充放电策略 功率分配策略 系统仿真 光储直柔
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利用Sigmoid函数所建隧道围岩全过程位移曲线的应用及效果验证
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作者 蒋朝谦 《四川水泥》 2024年第9期175-177,共3页
隧道围岩位移能够综合反映隧道施工过程中围岩稳定性及支护效果,但实际工程中掌子面前方围岩位移难以监测,导致难以得到围岩全过程位移曲线。为了获取隧道围岩全过程位移曲线,基于Sigmoid函数、遗传算法及数值计算方法,建立了隧道围岩... 隧道围岩位移能够综合反映隧道施工过程中围岩稳定性及支护效果,但实际工程中掌子面前方围岩位移难以监测,导致难以得到围岩全过程位移曲线。为了获取隧道围岩全过程位移曲线,基于Sigmoid函数、遗传算法及数值计算方法,建立了隧道围岩全过程位移曲线,并验证了该曲线的预测效果。选取某公路隧道不同围岩级别工况下的典型位移监测数据,对所提出的预测方法进行验证,结果表明:基于Sigmoid函数的隧道围岩全过程位移曲线能够较为准确地预测围岩位移,预测精度和可靠性较高,适用于不同围岩级别及开挖方法,可为施工阶段围岩稳定性评价提供参考。 展开更多
关键词 隧道工程 位移曲线 位移预测 sigmoid函数 遗传算法
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浅谈一种基于Sigmoid轨迹规划的相邻交叉耦合同步调平控制策略
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作者 孙家庆 常振鑫 +2 位作者 李召芹 李丰硕 韩宁 《中国设备工程》 2024年第6期124-126,共3页
随着武器装备的发展,雷达、天线、激光武器和火炮等军事设备都配有自动化调平系统,为了适应多变的战场环境,提高机动性能和战场生存能力,需尽可能地提高调平系统调平精度、调平效率,保证调平过程稳定。本文提出了一种基于Sigmoid轨迹规... 随着武器装备的发展,雷达、天线、激光武器和火炮等军事设备都配有自动化调平系统,为了适应多变的战场环境,提高机动性能和战场生存能力,需尽可能地提高调平系统调平精度、调平效率,保证调平过程稳定。本文提出了一种基于Sigmoid轨迹规划的相邻交叉耦合同步调平控制策略,可以适用于多点调平场合。采用D-H坐标法建立平台位姿解算模型,得到各调平支腿所需位移。基于Sigmoid函数对位移调整过程进行规划,得到支腿位移和时间的序列关系。根据相邻交叉耦合同步控制策略,建立各支腿耦合关系,通过同步控制器实现各支腿按同步比例系数的同步调整。经SimMechanics动力学建模Simulink仿真结果如下:各支腿位移调整曲线平滑、调平效率高、调平误差小于3′,同步误差减小约55.6%,同步调整时间减小约44.4%。 展开更多
关键词 多点调平 位姿解算 sigmoid函数 相邻偏差耦合
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一种用Sigmoid函数进行加权融合的图像去雾算法 被引量:3
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作者 火元莲 张乔森 +1 位作者 张金石 范宏栋 《计算机工程与科学》 CSCD 北大核心 2023年第9期1621-1628,共8页
为了解决图像去雾过程中在前景和天空区域过渡不平滑以及透射率融合不精确、恢复图像色彩不自然等问题,提出了一种用Sigmoid函数进行加权融合的图像去雾算法。该算法在R、G、B共3个通道上使用不同的衰减常数,并以Sigmoid作为权重函数将... 为了解决图像去雾过程中在前景和天空区域过渡不平滑以及透射率融合不精确、恢复图像色彩不自然等问题,提出了一种用Sigmoid函数进行加权融合的图像去雾算法。该算法在R、G、B共3个通道上使用不同的衰减常数,并以Sigmoid作为权重函数将基于颜色衰减先验对天空区域的估计透射率和基于暗通道先验对前景区域的估计透射率进行融合,最后通过大气散射模型恢复出无雾图像。实验结果表明,该算法对包含有天空区域的雾图的去雾效果更优,复原后的图像清晰而且色彩自然,提升了图像的主观视觉效果,同时客观对比也表明了该算法的有效性和适用性。 展开更多
关键词 图像去雾 暗通道 颜色衰减先验 sigmoid函数 大气散射模型
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基于改进Sigmoid函数的PMSM调速系统自抗扰控制 被引量:3
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作者 李白雅 封志鹏 +2 位作者 王锦涛 杨城健 张宇祥 《传感器与微系统》 CSCD 北大核心 2023年第6期90-93,共4页
为实现永磁同步电机(PMSM)转速的快速、稳定控制,提出一种基于改进Sigmoid函数的自抗扰控制(ADRC)方法。首先,对Sigmoid函数进行了分析和改进,引入非线性因子;接着,利用改进Sigmoid函数替代传统非线性函数设计了PMSM调速系统的改进型微... 为实现永磁同步电机(PMSM)转速的快速、稳定控制,提出一种基于改进Sigmoid函数的自抗扰控制(ADRC)方法。首先,对Sigmoid函数进行了分析和改进,引入非线性因子;接着,利用改进Sigmoid函数替代传统非线性函数设计了PMSM调速系统的改进型微分跟踪器(TD)、改进型扩张状态观测器(ESO)和改进型非线性状态误差反馈(NLSEF)控制律,并借助李雅普诺夫(Lyapunov)函数证明了所设计的改进型ESO具有渐进稳定性;随后,证明改进型ADRC误差系统的渐进稳定性;最后,对该策略进行了仿真分析。结果表明:在PMSM调速系统中,改进型ADRC比传统ADRC和PI控制具有更好的动态性能和抗扰性能。 展开更多
关键词 永磁同步电机 自抗扰控制 改进sigmoid函数 渐进稳定
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Surgical treatment of pulsatile tinnitus related to the sigmoid sinus
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作者 Yuxuan Xing Song Gao +4 位作者 Yuchen Zhou Shenghua Song Ling Lu Jie Chen Yanhong Dai 《Journal of Otology》 CSCD 2023年第1期21-25,共5页
Objective: Tinnitus-a common clinical symptom-can be categorized into pulsatile tinnitus(PT) and non-PT. Among these, PT is usually associated with sigmoid sinus symptoms, such as sigmoid sinus wall defect or divertic... Objective: Tinnitus-a common clinical symptom-can be categorized into pulsatile tinnitus(PT) and non-PT. Among these, PT is usually associated with sigmoid sinus symptoms, such as sigmoid sinus wall defect or diverticulum, for which various surgical treatments are available. We have discussed the clinical efficacy of surgery for sigmoid sinus-associated PT via the transmastoid approach in this study.Methods: We conducted a retrospective review of 4 patients who underwent surgery for sigmoid sinusassociated PT via the transmastoid approach at Nanjing Drum Tower Hospital from January to December2020. Of these, 2 patients had sigmoid sinus wall defect and 2 had sigmoid sinus diverticulum. Postoperative tinnitus grading and surgical efficacy were determined.Results: After surgery, PT dissolved in 3 patients, while tinnitus significantly decreased in 1 patient.During the follow-up period of 12-18 months, none of the 4 patients showed complications related to increased intracranial pressure or venous sinus thrombosis, and tinnitus symptoms disappeared in 3patients without recurrence, although 1 patient occasionally developed tinnitus. Postoperative thin-slice CTA of the temporal bone indicated that the sigmoid sinus bone wall defect or diverticulum was completely repaired with a thick soft tissue coverage.Conclusion: Surgical repair of sigmoid sinus-associated PT via the transmastoid approach deserves clinical promotion as it exhibited better efficiency while being relatively less invasive. 展开更多
关键词 Pulsatile tinnitus sigmoid sinus wall defect sigmoid sinus diverticulum Efficacy of surgery Transmastoid approach
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Anesthetic management of a patient with preoperative R-on-T phenomenon undergoing laparoscopic-assisted sigmoid colon resection:A case report
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作者 Xiao-Xi Li Yun-Feng Yao Hong-Yu Tan 《World Journal of Clinical Cases》 SCIE 2023年第9期2098-2103,共6页
BACKGROUND The R-on-T phenomenon is a malignant arrhythmia associated with potentially catastrophic consequences.It may initiate ventricular tachycardia or ventricular fibrillation,which can result in syncope or sudde... BACKGROUND The R-on-T phenomenon is a malignant arrhythmia associated with potentially catastrophic consequences.It may initiate ventricular tachycardia or ventricular fibrillation,which can result in syncope or sudden cardiac death.This manifestation poses a great challenge for anesthesiologists.However,it is rarely encountered in the perioperative setting.CASE SUMMARY We herein present a case in which the R-on-T phenomenon was incidentally revealed by 24-h Holter monitoring in a patient diagnosed with sigmoid colon cancer.Careful evaluation and treatment with mexiletine were carried out preoperatively under consultation with a cardiovascular specialist,and surgery was uneventfully performed under general anesthesia after thorough preparation.CONCLUSION Physicians should be vigilant about this infrequent but potentially fatal arrhythmia.Our experience suggests that the anesthetic process can be greatly optimized with careful preparation. 展开更多
关键词 R-on-T phenomenon Premature ventricular contraction sigmoid colon cancer sigmoid colon resection General anesthesia Case report
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Recurrent Sigmoid Volvulus after Sigmoidectomy: 3 Clinical Cases
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作者 Murielle Etiennette Julie Note Madzele Didace Massamba Miabaou +6 位作者 Pierlesky Elion Ossibi Moïse Service Yanguedet Noé Henschel Motoula Latou Prude Pertinie Avala Giresse Bienvenu Tsouassa Wa Ngono Meddi Bhodého Monwongui Carmich Nzaka Moukala 《Surgical Science》 2023年第12期712-719,共8页
Introduction: Recurrent sigmoid volvulus is a medical and surgical emergency. It is the recurrence of a twisting of the sigmoid loop around its mesenteric axis initiating an occlusion by strangulation. The risk factor... Introduction: Recurrent sigmoid volvulus is a medical and surgical emergency. It is the recurrence of a twisting of the sigmoid loop around its mesenteric axis initiating an occlusion by strangulation. The risk factors of colonic volvulus are: a dolichosigmoid, a chronic constipation, a tumor, …In Western countries, recurrences of sigmoid volvulus after surgery are rare and due to a non resection of a dolicho-megacolon. Most African studies do not report any recurrence of sigmoid volvulus after sigmoidectomy. This work aims to describe three original cases of recurrence of sigmoid volvulus after sigmoidectomy recorded at the University Hospital of Brazzaville and to analyze their causes and surgical management. Clinical Observation: We studied the cases of three male patients, whose average age was 73 years, each of them having a history of chronic constipation and sigmoidectomy for sigmoid volvulus with an average delay of recurrence of 5.3 years. They all underwent emergency laparotomy for acute intestinal obstruction on scarred abdomen. The surgery permitted to unfold a recurrent volvulus of the sigmoid associated with circumferential scar fibrosis on the volvulated sigmoid loop. A second colectomy was performed. The histological results of the surgical specimens were normal for two patients and revealed signs of tissue necrosis for the third patient. The postoperative outcome was without incident for two patients. The third patient died after developing a septic shock. Conclusion: Recurrent sigmoid volvulus after sigmoidectomy is rare. The etiological factors for our three patients were incomplete sigmoidectomy during the first operation and chronic constipation. 展开更多
关键词 Recurrent Volvulus sigmoid sigmoidECTOMY
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