共查询到18条相似文献，搜索用时 515 毫秒
1.
林芳 《Journal of Zhangzhou Technical Institute》2008,10(4)
对RSVP协议进行扩展,使RSVP的信令消息与移动口的绑定更新消息绑定在一起发送,在移动节点与通信节点间建立通信路由路径的同时对沿路的资源进行预留和适当的资源管理,保证服务质量,实现在无线移动环境中的QoS保障。 相似文献
2.
本文围绕基于Internet的网络化测试系统的实时性问题,基于RSVP协议的实时性改善方案等方面进行了较系统、深入的研究。 相似文献
3.
本地差分隐私（LDP）频率估计是数据挖掘领域的一个重要组成部分,目的是在满足LDP的前提下计算特定数据项出现的频率。在基于云服务的应用中,LDP频率估计实现了数据采集过程与数据分析过程的隐私保护,可应用于频繁模式挖掘、恶意攻击检测等。但是LDP频率估计存在随机化噪声较多、依赖数据量较大、高维数据分析准确性较低等缺点。介绍LDP频率估计过程及其存在的性能分析问题,详细讨论LDP频率估计算法,主要包括单值频率估计方法、泛化频率估计方法、集合数据频率估计方法,并对下一步研究方向提出建议。 相似文献
4.
本文分析比较了几个常见IP组播协议原理、方法与特点，指出了当前Internet组播协议存在的问题．并提出相应的解决方法建议。 相似文献
5.
探讨了基于BGP／MPIS的VPN方案的实现细节及扩展性，给出了VPN站点内主机利用非VRF访问Internet的方法。 相似文献
6.
目的:评估腹腔镜(LDP)与开腹胰体尾切除术(ODP)的并发症发生率和肿瘤清除效果。创新点:本组病例的腹腔镜手术组采用endo-GIA缓慢压榨方法处理胰腺残端,并采用根治性顺行模块化胰脾切除术,获得了较低的术后胰漏发生率和良好的手术清除效果。方法:收集4年间实施胰体尾切除手术的胰腺导管腺癌病例资料,进行回顾性分析。结论:22例胰腺导管腺癌进行了LDP手术,76例病人进行了ODP手术。比较LDP和ODP组,两组在胰漏(P=0.62)、腹腔内脓肿(P=0.44)和术后出血(P=0.34)发生率无显著性差异。LDP组和ODP组术中获取的淋巴结数量(11.2±4.6 vs.14.4±5.5,P=0.44)和淋巴结阳性病例数(36%vs.41%,P=0.71)无显著性差异。切缘阳性发生率(9%vs.13%,P=0.61)也无显著性差异。LDP组平均生存期(29.6±3.7)月,ODP组为(27.6±2.1)月,无显著性差异(P=0.35)。综上所述,腹腔镜胰体尾切除术对早期的胰腺导管癌是安全有效的。采用endo-GIA缓慢压榨方法可以预防术后胰漏发生,腹腔镜下根治性顺行模块化胰腺切除有利于肿瘤清除。腹腔镜手术可以达到和传统开腹手术相似的肿瘤清除效果。 相似文献
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8.
阮立志 《连云港职业技术学院学报》2001,14(2):16-19
服务质量是Internet当前致力解决的一个问题。结论IPv6,RSVP着重探讨了MPLS、IntServ以及DiffServ三种解决方案。 相似文献
9.
本文提出了一种使用QoS保护来增强当前QoS路由的方法。在MPLS网络内,预先确定需保护的网段。LSP请求除建立工作路径外,还创建一条备份路径（本地的、反转的或全局的）。本方法考虑不同的QoS参数,如网络负载均衡、资源优化和LSP请求拒绝的最小化。QoS保护被定义为QoS参数的一个功能．同时,引入一种在当前多种QoS路由算法中增加QoS保护的结构,并给出了选择最适合的保护方法的备份决策模式。 相似文献
10.
范敏 《绵阳师范高等专科学校学报》2014,(8):89-94
在基于RFID技术的商业活动中,一项非常重要的任务是保护供应链上各个企业的商业秘密不因RFID标签所有权的转换而带来风险.基于Hash函数和对称密码体制,提出了一种适合于供应链环境的轻量级RFID标签所有权转换协议.协议具有抗重放攻击、抗异步攻击、抗假冒攻击、抗内部攻击等特性,并能确保前向、后向隐私安全性.与现有典型的RFID标签所有权转移协议相比,协议的安全性、隐私性好,效率高,能保护企业的商业秘密,具有很好的现实意义. 相似文献
11.
Ai-bin Zhang Ye Wang Chen Hu Yan Shen Shu-sen Zheng 《Journal of Zhejiang University. Science. B》2017,18(6):532-538
Objective
The aim of this study was to compare complications and oncologic outcomes of patients undergoing laparoscopic distal pancreatectomy (LDP) and open distal pancreatectomy (LDP) at a single center.Methods
Distal pancreatectomies performed for pancreatic ductal adenocarcinoma during a 4-year period were included in this study. A retrospective analysis of a database of this cohort was conducted.Results
Twenty-two patients underwent LDP for pancreatic ductal adenocarcinoma, in comparison to seventy-six patients with comparable tumor characteristics treated by LDP. No patients with locally advanced lesions were included in this study. Comparing LDP group to LDP group, there were no significant differences in operation time (P=0.06) or blood loss (P=0.24). Complications (pancreatic fistula, P=0.62; intra-abdominal abscess, P=0.44; postpancreatectomy hemorrhage, P=0.34) were similar. There were no significant differences in the number of lymph nodes harvested (11.2±4.6 in LDP group vs. 14.4±5.5 in LDP group, P=0.44) nor the rate of patients with positive lymph nodes (36% in LDP group vs. 41% in LDP group, P=0.71). Incidence of positive margins was similar (9% in LDP group vs. 13% in LDP group, P=0.61). The mean overall survival time was (29.6±3.7) months for the LDP group and (27.6±2.1) months for LDP group. There was no difference in overall survival between the two groups (P=0.34).Conclusions
LDP is a safe and effective treatment for selected patients with pancreatic ductal adenocarcinoma. A slow-compression of pancreas tissue with the GIA stapler is effective in preventing postoperative pancreatic fistula. The oncologic outcome is comparable with the conventional open approach. Laparoscopic radical antegrade modular pancreatosplenectomy contributed to oncological clearance.12.
Jia-fei Yan Tian-tao Kuang Da-yong Ji Xiao-wu Xu Dan-song Wang Ren-chao Zhang Wei-wei Jin Yi-ping Mou Wen-hui Lou 《Journal of Zhejiang University. Science. B》2015,16(7):573-579
Objective: To compare the peri-operative outcomes for laparoscopic distal pancreatectomy (LDP) and open distal pancreatectomy (ODP) for benign or premalignant pancreatic neoplasms in two institutions. Methods: This prospective comparative study included 91 consecutive patients who underwent LDP (n=45) or ODP (n=46) from Jan. 2010 to Dec. 2012. Demographics, intra-operative characteristics, and post-operative outcomes were compared. Results: The median operating time in the LDP group was (158.7±38.3) min compared with (92.2±24.1) min in the ODP group (P<0.001). Patients had lower blood loss in LDP than in the ODP (122.6±61.1) ml vs. (203.1±84.8) ml, P<0.001). The rates of splenic conservation between the LDP and ODP groups were similar (53.3% vs. 47.8%, P=0.35). All spleen-preserving distal pancreatectomies were conducted with vessel preservation. LDP also demonstrated better post-operative outcomes. The time to oral intake and normal daily activities was faster in the LDP group than in the ODP group (1.6±0.5) d vs. (3.2±0.7) d, P<0.01; (1.8±0.4) d vs. (2.1±0.6) d, P=0.02, respectively), and the postoperative length of hospital stay in LDP was shorter than that in ODP (7.9±3.8) d vs. (11.9±5.8) d, P=0.006). No difference in tumor size (4.7±3.2) cm vs. (4.5±1.8) cm, P=0.77) or overall pancreatic fistula rate (15.6% vs. 19.6%, P=0.62) was found between the groups, while the overall post-operative complication rate was lower in the LDP group (26.7% vs. 47.8%, P=0.04). Conclusions: LDP is safe and effective for benign or premalignant pancreatic neoplasms, featuring lower blood loss and substantially faster recovery. 相似文献
13.
教育学以"教育"活动作为逻辑起点具有研究对象与逻辑起点重合的缺陷,相应地教育技术学以"借助于技术的教育"活动作为逻辑起点也具有同样的问题。对教育技术学的逻辑起点的认识只有当教育技术学发展到一定阶段之后才成为可能,在这个过程中,需要处理好逻辑起点与研究起点、历史起点的关系。最后,作者提出了重新认识逻辑起点的问题及其重要性。 相似文献
14.
局部方向模式（LDP）利用8个Kirsch模板与3×3局部邻域卷积得到局部的边缘梯度值,然后取绝对值并排序,最后将最大的三个梯度所在的方向信息编码成一个八位二进制数;其不足之处在于将边缘梯度求绝对值后进行编码,因为边缘梯度值的正负号表示梯度两个对立的变化趋势,求绝对值也就忽视了梯度的变化趋势信息,而梯度的变化趋势有益于鉴别人脸特征的表达.针对LDP的不足提出了一种改进方案,直接利用局部邻域的原始边缘梯度值进行人脸特征提取.实验结果表明,改进方案的正确识别率高于原方案. 相似文献
15.
Laser shock processing (LSP), also known as laser peening, is a novel surface treatment technique in the past few years. Compressive
residual stresses which imparted by LSP are very important for improving fatigue, corrosion and wear resistance of metals.
Finite element analysis (FEA) simulation using ABAQUS software has been applied to predict residual stresses induced by LSP
on Ti-6Al-4V titanium alloy with laser pulse duration 30 ns and water confined ablation mode. The residual stress field generated
by different shape laser spots was studied, and the square laser spot is shown the most suitability for avoiding stress lack
phenomenon and overlapping LSP. Surface residual stresses and plastically affected depth within single square spot both increased
with the increase of laser intensity and laser shock times. Furthermore, compared with circle and ellipse spot, the residual
stress distribution in overlapping square spots is very uniform only with small overlapping ratio. LSP with square spot can
process advantageous residual stress field, and this technique will be used widely. 相似文献
16.
论影响日本教育政策的因素 总被引：6，自引：0，他引：6
日本战后教育政策的形成受到多方面因素的影响。自民党的一党执政对教育政策的形成起着决定性作用；文部省通过与自民党的合作与妥协在教育政策制订过程中发挥着重要作用；财界和产业界的教育要求通过国家权力的媒介也反映到教育政策中来；作为最重要的反对力量，日本教师工会在地方教育政策的实施中所产生的影响远远大于中央教育决策中产生的影响。 相似文献
17.
Viniti Vaish 《Cambridge Journal of Education》2014,44(2):199-215
This paper analyzes whole language and code-based skills approaches in early literacy and the specific patterns of interaction present in both approaches. Nineteen hours of video data were coded to analyze the nature of whole language versus code-based skills instruction and document the allocation of time spent on each approach in a reading program. Data come from a cross-sectional study in Singapore where the Learning Support Program (LSP), a reading program for low-track students, was studied in five schools. Overall, 73% of class time in the dataset showed code-based skills instruction. However, the approach to instruction changed within the LSP in a linear fashion. Though in the early years of the LSP there was an over-emphasis on code-based skills and lack of variety in patterns of interaction, in later years there was a balance between whole language and code-based skills and a wider variety of interactional patterns. 相似文献
18.
This paper presents surface modifications of aluminum-alloy induced by laser-shock processing (LSP). In the first part, the basic principles are discussed to provide an overview of the physical processes involved in laser shock processing, and to introduce pressure loadings generated by different laser generators. In the second part, emphases are given to the effects of laser intensity, target material, laser pulse duration and laser wavelength, and uniform and localized modeling of fatigue behavior after LSP. In the third part,experimental results are given to show the laser-induced pure mechanical effects on aluminum-alloy by using LSP. 相似文献