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Poggio和Smale最近提出的学习理论的一个关键算法(A key algorithm,KA)可用于非线性分类和回归,并避免求解二次规划,但几乎所有的样本是“支持向量”。为此提出了一种稀疏KA算法(SKA),通过设计特定的优化函数,SKA能有效减少“支持向量”,并具备良好的推广能力。将SKA应用于两个实际的模式识别问题,并与支持向量机(SVM)进行比较,验证了SKA的有效性。 相似文献
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在数据挖掘中,支持向量机是被广泛应用的一种分类算法,其核函数的选择及参数的设定没有有效的标准。本文采用混合核函数构造兼顾学习能力和泛化性能的支持向量机算法,并利用粒子群算法来确定支持向量机的参数。应用基于混合核函数的PSO SVM算法对一个经典的分类测试数据集进行分类,将该算法与单一核函数支持向量机算法的分类结果进行比较,结果表明所提出的算法的分类性能有明显提升。 相似文献
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从最小二乘支持向量机的稀疏表达出发,构建高效的基于稀疏最小二乘支持向量机的网络入侵检测模型,提出了一种通过基于核空间近似策略的有效低秩逼近来有效减小原始训练样本集中的支持向量数来实现最终模型的稀疏表达.以MIT KDD99数据集为基础,对所提出方法进行有效性验证,并与利用剪枝策略通过递归过程中不断减少模型中支持向量个数的稀疏化方法、基本最小二乘支持向量机以及标准支持向量机方法的性能进行对比.结果表明:基于核空间近似的最小二乘支持向量机稀疏化与标准最小二乘支持向量机相当;此外稀疏最小二乘支持向量机能够提高入侵检测响应速度. 相似文献
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在分析基本微粒群优化算法(PSO)和支持向量机(SVM)原理的基础上,采用带有末位淘汰机制的微粒群优化算法优化支持向量机的参数,建立了延迟焦化装置粗汽油干点软测量的微粒群支持向量机模型.该方法利用支持向量机结构风险最小化原则和PSO算法快速全局优化的特点,用于软测量建模.仿真实验表明:所建模型的泛化性能较好,模型具有较高的精度. 相似文献
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针对最小二乘支持向量机(LS-SVM)在进行回归预测时存在的稀疏性缺陷问题,采用固定尺度最小二乘支持向量机,即固定支持向量数量进行改进。仿真结果表明:固定尺度最小二乘支持向量机在训练各种样本数据集时,有效地避开了LS-SVM中的稀疏性问题,且训练速度快,同时具有良好的预测精度。 相似文献
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目的 研究广义似然比检验(GLRT)与支持向量机(SVM)相结合的混合法在基因芯片表达数据分类研究中的应用效果.方法 结合 Golub研究的白血病基因表达数据,利用GLRT寻找白血病表达水平存在显著性差异的基因,再使用SVM对白血病进行分类.结果 基于GLRT鉴别得到的特征基因有很强的代表性,SVM分类的效果明显优于其他方法.结论 混合法在解决数据量大、维数高、样本量小、非线性问题中具有很强的优势,可以有效的用于基因芯片表达数据的分类研究. 相似文献
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Objective: To evaluatel the value of D-dimers in patients with acute aortic dissection (AAD). Methods: This study consisted of 16 patients with AAD and 27 non-AAD patients. Serum D-dimets were measured by Sta-Liatest D-DI immunoturbidimetric assay. Results: D-dimer level was higher (P < 0.001) in patients with AAD(7.91 ± 5.52 μg/ml) than that in non- AAD group(1.57±1.24 μg/ml). D-dimer was positive (>0.4 μg/ml) in all patients with AAD and in 10 control group patients (37%). Among patients with acute AAD, D-dimers tended to be higher in Stanford A than in Stanford B (8.67 ± 4.31 μg/ml vs. 3.24±1.27 μg/ml, P <0.01). D-dimer values tended to be higher in more extended disease(3.84 ± 1.65 μg/ml, 8.57 ± 3.58 μg/ml and 11.87 ± 5.69 μg/ml in thoracic aorta, thoracic and abdominal aorta, thoracic and abdominal aorta and iliacal arteries, respectively, P < 0.05 for both 8.57 ± 3.58 and 11.87 ± 5.69 vs. 3.84 ± 1.65 ). Including the control group into the analysis, we found a sensitivity of 100%, a negative predictive value of 100%, and a specificity of 66% and a positive predictive value of 64% for D-dimer in diagnosis of AAD in our patients with suspected AAD. Conclusion: D-dimer was elevated in patients with AAD. A negative D-dimer test result could be useful in excluding AAD. 相似文献
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Jiageng Zhu Jun Li Ruipeng Ji Jianghao Su Mingshun Shen Zhigang Cao 《南京医科大学学报(自然科学版)》2007,21(2):125-128
Objective: To set up a simple and reliable rat model of combined liver-kidney transplantation. Methods: SD rats served as both donors and recipients. 4℃ sodium lactate Ringer's was infused from portal veins to donated livers,and from abdominal aorta to donated kidneys, respectively. Anastomosis of the portal vein and the inferior vena cava (IVC) inferior to the right kidney between the graft and the recipient was performed by a double cuff method, then the superior hepatic vena cava with suture. A patch of donated renal artery was anastomosed to the recipient abdominal aorta. The urethra and bile duct were reconstructed with a simple inside bracket. Results: Among 65 cases of combined liver-kidney transplantation, the success rate in the late 40 cases was 77.5%. The function of the grafted liver and kidney remained normal. Conclusion: This rat model of combined liver-kidney transplantation can be established in common laboratory conditions with high success rate and meet the needs of renal transplantation experiment. 相似文献
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APPLICATION OF LORNOXICAM TO PATIENT-CONTROLLED ANALGESIA IN PATIENTS UNDERGOING ABDOMINAL SURGERIES 总被引:13,自引:0,他引:13
Hong Zhao Tie-hu Ye* Zhi-yi Gong Yang Xue Zhang-gang Xue and Wen-qi HuangDepartment of Anesthesiology Peking Union Medical College Hospital Chinese Academy of Medical Sciences & Peking Union Medical College Beijing Department of Anesthesiology Zhongshan Hospital Fudan University Shanghai Department of Anesthesiology the First Affiliated Hospital Zhongshan University Guangzhou 《中国医学科学杂志(英文版)》2005,20(1):59-62
FOR anesthesiologis s ,treatingpostoperativepainhas alwaysbeen a problem.Althoughopioidshave been provedtobe effective,theirsideeffectscouldnotbeignored.With thedevelopmentofscienceand pharmacology,many drugs with aspectsof satisfactoryanalgesicefficacyand couldbe welltoleratedby patientshave been developed.And lornoxicamisone of them, which isa non-steroidalanti-inflammatorydrug (NSAID ), with analgesic, anti-infl-ammatory,andantipyreticproperties.Itseliminationhalf-time(3 to 5 hours) isle… 相似文献
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Tao Ye * Zhi-quan Liu Jian-jun Mu Xi-han Fu Jun Yang Bao-lin Gao and Xiao-hong Zhang Department of Cardiology First Hospital of Xi'an Jiaotong University Xi'an Hanzhong Cardiovascular Institute Hanzhong 《中国医学科学杂志(英文版)》2004,19(4):248-251
Objective To observe blood pressure change with age in salt-sensitive teenagers whose salt sensitivity were determined by repeated testing.Methods Salt sensitivity was determined through intravenous infusion of normal saline combined with volume-depletion by oral diuretic furosemide in 55 teenagers. After five years, salt sensitivity was re-examined and subject blood pressure was followed up. Blood pressure changes in salt-sensitive teenagers were compared to that of non-salt sensitive teenagers over five years.Results After 5 years, the repetition rate of salt sensitivity determined by intravenous saline loading is 92.7%. In teenagers with salt sensitivity on the baseline, both the systolic blood pressure increments and increment rates were much higher than non-salt sensitive teenagers (12.7±12.1 mmHg vs. 2.8±5.2 mmHg, P< 0.01; 12.2%± 12.0% vs. 2.5% ±4.4%, P< 0.001,respectively). There was a similar trend for diastolic blood pressure (8.4 ± 6.4 mmHg vs. 3.7 ± 6.4 mmHg, P = 0.052; 13.2% ±10.6 % vs. 6.8%± 10.1%, P = 0.053, respectively).Conclusions Salt sensitivity determined by intravenous saline loading showed good reproducibility. Blood pressure increments with age were much higher in salt-sensitive teenagers than non-salt sensitive teenagers, especially in terms of systolic blood pressure. 相似文献
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Xi-zhao Sun Zhi-wei Zhang 《中国医学科学杂志(英文版)》2005,20(3):221-221
Shock wave lithotripsy (SWL) is a treatment of choice for upper urinary stones. However, this procedure is inappropriate for obese patients because the focus is often unable to reach the target owing to the limited focal distance in shock wave source. Although treating such patients in a blast path may increase the application length of shock wave source, it's difficult to find this path on the lithotripter monitor. For this reason, we invented an adjustable calibration marker in order to set an effective focus in the shock wave hath. 相似文献
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Excess production of reactive oxygen species(ROS)of mitochondrion mediated by hyperglycemia is the common pathogenesis of angiopathic complications of diabetes.TCM holds that the damp from the dysfunction of spleen.kidney and liver is the causative factor of complications of diabetes.This is similar to the mechanism of Ros resulting in angiopathic complications of diabetes.When the angiopathic complications of type II diabetes mellitus(T2DM)are difierentiated as caused by turbid damp in TCM can be explained as ROS.Since the obstruction of pathogenic damp in channels and collaterals is said to be the main pathogenesis,the treating principle should be dissolving the damp to remove the obstruction. 相似文献
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INTRODUCTION Obesity is a complex emergent problem, which can be possibly solved not only by the diet but also by the life style and promotion of a constant physical exercise. 1, 2 No doubt careful attentions must be given to the nutritional condition of obese people, the dietary habits, the somatic build (i.e. distribution of fat mass) and the organic functions linked to formation of the fat mass. All the parameters should be constantly monitored before, during and after a diet treatment. 3, 4, 5 相似文献
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People with dysglycemia are at high risk for atherosclerotic diseases. This study aims at investigating the atherosclerotic vascular damage in dysglycemia its metabolic origin in Tibetan population.…… 《中国医学科学杂志(英文版)》2007,22(2):F0003-F0003
People with dysglycemia are at high risk for atherosclerotic diseases. This study aims at investigating the atherosclerotic vascular damage in dysglycemia and its metabolic origin in Tibetan population. 相似文献
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Objective: To observe the therapeutic effects in acupunture treatment of primary dysmenorrhea combined with spinal Tui Na, and study its mechanism. Methods: Thirty cases of the treatment group were treated by acupuncture combined with spinal Tui Na, and thirty cases in the control group were treated by routine acupuncture. Results: The total effective rate was 93.3% in the treatment group, and 73.3% in the control group, with a significant difference between the two groups (P<0.05). Conclusions: Acupuncture combined with spinal Tui Na has good prospects for treatment of primary dysmenorrhea. 相似文献
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In treating chronic nephropathy,Luo Lingjie,a chief physician,pays attention to regulating the balance between yin and yang,treating infection if present,and removing pathogenic factors.He prescribes gentle drugs and uses carefully strongly warming-tonifying ones,emphasizes the importance of persuading the patient to persist in treatment with medication and nurse one's health for recuperation,and is good at combined use of TCM and western medicine therapy and brings the merits of various therapies into full play,with obvious theraoeutic effects. 相似文献