无线Mesh网络(Wireless Mesh network, WMN)中,链路拥塞会导致较长的传输时延和排队时间,因此将链路负载均衡与服务质量结合起来一直是研究热点.本文针对多目标路由优化管理的关键问题,将路由问题表述为整数线性规划(Integer linear pro...无线Mesh网络(Wireless Mesh network, WMN)中,链路拥塞会导致较长的传输时延和排队时间,因此将链路负载均衡与服务质量结合起来一直是研究热点.本文针对多目标路由优化管理的关键问题,将路由问题表述为整数线性规划(Integer linear programming, ILP)模型,并将无线Mesh网络与软件定义网络(Software defined network, SDN)结合,设计了适应于SD-WMN架构的多目标函数、约束条件以及整体的网络优化模型,此外,由于该整数线性规划模型是NP完全的,本文将改进的人工蜂群的启发式优化算法引入到路由优化算法中,以获得源节点和目的节点之间传输流量的理想路径.本文所提出方法在Mininet网络模拟工具中的仿真结果证明了该算法的有效性,与OSPF、SDNR以及遗传蚁群优化(G-ACO)相比,所提出方法在丢包率、往返时间和负载均衡方面均有不错的改善.展开更多
Despite the growing demand for transparent conductive films in smart and wearable electronics for electromagnetic interference(EMI)shielding,achieving a flexible EMI shielding film,while maintaining a high transmittan...Despite the growing demand for transparent conductive films in smart and wearable electronics for electromagnetic interference(EMI)shielding,achieving a flexible EMI shielding film,while maintaining a high transmittance remains a significant challenge.Herein,a flexible,transparent,and conductive copper(Cu)metal mesh film for EMI shielding is fabricated by self-forming crackle template method and electroplating technique.The Cu mesh film shows an ultra-low sheet resistance(0.18Ω□^(-1)),high transmittance(85.8%@550 nm),and ultra-high figure of merit(>13,000).It also has satisfactory stretchability and mechanical stability,with a resistance increases of only 1.3%after 1,000 bending cycles.As a stretchable heater(ε>30%),the saturation temperature of the film can reach over 110°C within 60 s at 1.00 V applied voltage.Moreover,the metal mesh film exhibits outstanding average EMI shielding effectiveness of 40.4 dB in the X-band at the thickness of 2.5μm.As a demonstration,it is used as a transparent window for shielding the wireless communication electromagnetic waves.Therefore,the flexible and transparent conductive Cu mesh film proposed in this work provides a promising candidate for the next-generation EMI shielding applications.展开更多
To explore the wide-frequency damping and vibration-attenuation performances in the application of aerospace components,the cylindrical sandwich shell structure with a gradient core of entangled wire mesh was proposed...To explore the wide-frequency damping and vibration-attenuation performances in the application of aerospace components,the cylindrical sandwich shell structure with a gradient core of entangled wire mesh was proposed in this paper.Firstly,the gradient cores of entangled wire mesh in the axial and radial directions were prepared by using an in-house Numerical Control weaving machine,and the metallurgical connection between skin sheets and the gradient core was performed using vacuum brazing.Secondly,to investigate the mechanical properties of cylindrical sandwich shells with axial or radial gradient cores,quasi-static and dynamic mechanical experiments were carried out.The primary evaluations of mechanical properties include secant stiffness,natural frequency,Specific Energy Absorption(SEA),vibration acceleration level,and so on.The results suggest that the vibration-attenuation performance of the sandwich shell is remarkable when the high-density core layer is at the end of the shell or abuts the inner skin.The axial gradient material has almost no influence on the vibration frequencies of the shell,whereas the vibration frequencies increase dramatically when the high-density core layer approaches the skin.Moreover,compared to the conventional sandwich shells,the proposed functional grading cylindrical sandwich shell exhibits more potential in mass reduction,stiffness designing,and energy dissipation.展开更多
BACKGROUND A meshoma formation and erosion to the small intestine is rare.Herein,we report one case of a meshoma that was not treated early;causing it to displace and erode the small intestine,with infection,complete ...BACKGROUND A meshoma formation and erosion to the small intestine is rare.Herein,we report one case of a meshoma that was not treated early;causing it to displace and erode the small intestine,with infection,complete control of symptoms was achieved after removal of the infected patch mass,no recurrence of hernia after 2 years of follow-up.CASE SUMMARY A 62-year-old male patient presented with recurrent abdominal pain repeatedly for 1 wk,which has worsened 2 d before admition,accompanied by fever.Five years before presentation he underwent right inguinal hernia Plug and patch repair approach.Two years ago,a computed tomography scan revealed a right lower abdominal mass with soft tissue density,measuring approximately 30 mm×17 mm,which was diagnosed as meshoma that was not treated.The patient had poorly controlled diabetes in the past year.CONCLUSION The formation of meshoma is rare,and that if not treated in time it might erode and require resection of the involved organ.展开更多
针对当前资产定位系统定位精度、建设成本和部署灵活性难以有效平衡的问题,基于BLE Mesh采用多维标度分析(MultiDimensional Scaling-Map,MDS-MAP)定位算法设计了一种资产定位系统。系统首先对原始接收信号强度(Received Signal Strengt...针对当前资产定位系统定位精度、建设成本和部署灵活性难以有效平衡的问题,基于BLE Mesh采用多维标度分析(MultiDimensional Scaling-Map,MDS-MAP)定位算法设计了一种资产定位系统。系统首先对原始接收信号强度(Received Signal Strength Indicator,RSSI)进行高斯-卡尔曼融合滤波,提高了RSSI值的准确性;然后利用生存时间(Time To Live,TTL)对中继节点进行约束,提高了数据传输的有效性;最后利用半径弥补法与Bellman-Ford融合迭代方案对生成的距离矩阵进行修正,减小了测距误差。实验结果表明,所设计的系统可有效完成蓝牙标签信息更新以及位置展示,平均定位精度达到了0.94 m。本系统具有成本低、工程实施方便的优点,有一定的应用价值和发展前景。展开更多
传统到达角度(Angle-Of-Arrival,AOA)/接受信号强度指示(Received Signal Strength Indicator,RSSI)混合定位往往需要多个锚节点布设阵列天线以实现高精度定位,为解决在锚节点资源受限下精度较低的问题,提出了一种基于Mesh网络的混合AOA...传统到达角度(Angle-Of-Arrival,AOA)/接受信号强度指示(Received Signal Strength Indicator,RSSI)混合定位往往需要多个锚节点布设阵列天线以实现高精度定位,为解决在锚节点资源受限下精度较低的问题,提出了一种基于Mesh网络的混合AOA/RSSI协作定位方法。仅有中心主锚节点提供AOA角度的情况下,采取最小二乘法对联合真实和虚拟锚节点所对应角度和距离信息进行初步定位;利用未知节点之间的协作通信和测距信息,位置估计问题被转换为无约束非线性优化问题,给予短距离链路更高权重,通过迭代求解最终实现协作定位。仿真结果表明,所提算法在锚节点资源受限情况下有效地提升了定位精度。展开更多
BACKGROUND In recent years,mesh has become a standard repair method for parastomal hernia surgery due to its low recurrence rate and low postoperative pain.However,using mesh to repair parastomal hernias also carries ...BACKGROUND In recent years,mesh has become a standard repair method for parastomal hernia surgery due to its low recurrence rate and low postoperative pain.However,using mesh to repair parastomal hernias also carries potential dangers.One of these dangers is mesh erosion,a rare but serious complication following hernia surgery,particularly parastomal hernia surgery,and has attracted the attention of surgeons in recent years.CASE SUMMARY Herein,we report the case of a 67-year-old woman with mesh erosion after parastomal hernia surgery.The patient,who underwent parastomal hernia repair surgery 3 years prior,presented to the surgery clinic with a complaint of chronic abdominal pain upon resuming defecation through the anus.Three months later,a portion of the mesh was excreted from the patient’s anus and was removed by a doctor.Imaging revealed that the patient’s colon had formed a t-branch tube structure,which was formed by the mesh erosion.The surgery reconstructed the structure of the colon and eliminated potential bowel perforation.CONCLUSION Surgeons should consider mesh erosion since it has an insidious development and is difficult to diagnose at the early stage.展开更多
BACKGROUND Vaginal stones are rare with current literature limited to case reports.Vaginal stones are classified as primary or secondary stones.Primary stones form in the vagina when there is urinary stasis.Secondary ...BACKGROUND Vaginal stones are rare with current literature limited to case reports.Vaginal stones are classified as primary or secondary stones.Primary stones form in the vagina when there is urinary stasis.Secondary stones form in the presence of a vaginal foreign body that acts as a nidus for the deposition of urinary salts.Foreign bodies,such as surgical mesh,make vaginal stone formation more likely,particularly in patients with urinary incontinence and conditions that predispose them to urinary calculi formation.CASE SUMMARY A 71-year-old female with a history of sacrocolpopexy,hyperaldosteronism,and urgency urinary incontinence presented with vaginal stone accumulation overlying two areas of vaginal sacrocolpopexy mesh exposure.The vaginal stones were initially removed to permit examination,but the stones reaccumulated at the site of the exposed mesh,later requiring definitive surgical management.CONCLUSION Patients with vaginal mesh exposure and conditions that predispose them to kidney stones are not ideal candidates for expectant management of mesh exposure,particularly if they have coexisting urinary incontinence.These individuals should be counseled about possible vaginal stone accumulation,and surgical management should be considered.展开更多
文摘无线Mesh网络(Wireless Mesh network, WMN)中,链路拥塞会导致较长的传输时延和排队时间,因此将链路负载均衡与服务质量结合起来一直是研究热点.本文针对多目标路由优化管理的关键问题,将路由问题表述为整数线性规划(Integer linear programming, ILP)模型,并将无线Mesh网络与软件定义网络(Software defined network, SDN)结合,设计了适应于SD-WMN架构的多目标函数、约束条件以及整体的网络优化模型,此外,由于该整数线性规划模型是NP完全的,本文将改进的人工蜂群的启发式优化算法引入到路由优化算法中,以获得源节点和目的节点之间传输流量的理想路径.本文所提出方法在Mininet网络模拟工具中的仿真结果证明了该算法的有效性,与OSPF、SDNR以及遗传蚁群优化(G-ACO)相比,所提出方法在丢包率、往返时间和负载均衡方面均有不错的改善.
基金This work was financially supported by the National Natural Science Foundation of China(Grant No.523712475,2072415 and 62101352)Shenzhen Science and Technology Program(RCBS20210706092343016).
文摘Despite the growing demand for transparent conductive films in smart and wearable electronics for electromagnetic interference(EMI)shielding,achieving a flexible EMI shielding film,while maintaining a high transmittance remains a significant challenge.Herein,a flexible,transparent,and conductive copper(Cu)metal mesh film for EMI shielding is fabricated by self-forming crackle template method and electroplating technique.The Cu mesh film shows an ultra-low sheet resistance(0.18Ω□^(-1)),high transmittance(85.8%@550 nm),and ultra-high figure of merit(>13,000).It also has satisfactory stretchability and mechanical stability,with a resistance increases of only 1.3%after 1,000 bending cycles.As a stretchable heater(ε>30%),the saturation temperature of the film can reach over 110°C within 60 s at 1.00 V applied voltage.Moreover,the metal mesh film exhibits outstanding average EMI shielding effectiveness of 40.4 dB in the X-band at the thickness of 2.5μm.As a demonstration,it is used as a transparent window for shielding the wireless communication electromagnetic waves.Therefore,the flexible and transparent conductive Cu mesh film proposed in this work provides a promising candidate for the next-generation EMI shielding applications.
基金Supports from the National Natural Science Foundation of China(Grant No.12272094,No.52205185 and No.51975123)the Natural Science Foundation of Fujian Province of China(Grant No.2022J01541 and No.2020J05102)the Key Project of National Defence Innovation Zone of Science and Technology Commission of CMC(Grant No.XXX-033-01)。
文摘To explore the wide-frequency damping and vibration-attenuation performances in the application of aerospace components,the cylindrical sandwich shell structure with a gradient core of entangled wire mesh was proposed in this paper.Firstly,the gradient cores of entangled wire mesh in the axial and radial directions were prepared by using an in-house Numerical Control weaving machine,and the metallurgical connection between skin sheets and the gradient core was performed using vacuum brazing.Secondly,to investigate the mechanical properties of cylindrical sandwich shells with axial or radial gradient cores,quasi-static and dynamic mechanical experiments were carried out.The primary evaluations of mechanical properties include secant stiffness,natural frequency,Specific Energy Absorption(SEA),vibration acceleration level,and so on.The results suggest that the vibration-attenuation performance of the sandwich shell is remarkable when the high-density core layer is at the end of the shell or abuts the inner skin.The axial gradient material has almost no influence on the vibration frequencies of the shell,whereas the vibration frequencies increase dramatically when the high-density core layer approaches the skin.Moreover,compared to the conventional sandwich shells,the proposed functional grading cylindrical sandwich shell exhibits more potential in mass reduction,stiffness designing,and energy dissipation.
文摘BACKGROUND A meshoma formation and erosion to the small intestine is rare.Herein,we report one case of a meshoma that was not treated early;causing it to displace and erode the small intestine,with infection,complete control of symptoms was achieved after removal of the infected patch mass,no recurrence of hernia after 2 years of follow-up.CASE SUMMARY A 62-year-old male patient presented with recurrent abdominal pain repeatedly for 1 wk,which has worsened 2 d before admition,accompanied by fever.Five years before presentation he underwent right inguinal hernia Plug and patch repair approach.Two years ago,a computed tomography scan revealed a right lower abdominal mass with soft tissue density,measuring approximately 30 mm×17 mm,which was diagnosed as meshoma that was not treated.The patient had poorly controlled diabetes in the past year.CONCLUSION The formation of meshoma is rare,and that if not treated in time it might erode and require resection of the involved organ.
文摘针对当前资产定位系统定位精度、建设成本和部署灵活性难以有效平衡的问题,基于BLE Mesh采用多维标度分析(MultiDimensional Scaling-Map,MDS-MAP)定位算法设计了一种资产定位系统。系统首先对原始接收信号强度(Received Signal Strength Indicator,RSSI)进行高斯-卡尔曼融合滤波,提高了RSSI值的准确性;然后利用生存时间(Time To Live,TTL)对中继节点进行约束,提高了数据传输的有效性;最后利用半径弥补法与Bellman-Ford融合迭代方案对生成的距离矩阵进行修正,减小了测距误差。实验结果表明,所设计的系统可有效完成蓝牙标签信息更新以及位置展示,平均定位精度达到了0.94 m。本系统具有成本低、工程实施方便的优点,有一定的应用价值和发展前景。
文摘传统到达角度(Angle-Of-Arrival,AOA)/接受信号强度指示(Received Signal Strength Indicator,RSSI)混合定位往往需要多个锚节点布设阵列天线以实现高精度定位,为解决在锚节点资源受限下精度较低的问题,提出了一种基于Mesh网络的混合AOA/RSSI协作定位方法。仅有中心主锚节点提供AOA角度的情况下,采取最小二乘法对联合真实和虚拟锚节点所对应角度和距离信息进行初步定位;利用未知节点之间的协作通信和测距信息,位置估计问题被转换为无约束非线性优化问题,给予短距离链路更高权重,通过迭代求解最终实现协作定位。仿真结果表明,所提算法在锚节点资源受限情况下有效地提升了定位精度。
文摘BACKGROUND In recent years,mesh has become a standard repair method for parastomal hernia surgery due to its low recurrence rate and low postoperative pain.However,using mesh to repair parastomal hernias also carries potential dangers.One of these dangers is mesh erosion,a rare but serious complication following hernia surgery,particularly parastomal hernia surgery,and has attracted the attention of surgeons in recent years.CASE SUMMARY Herein,we report the case of a 67-year-old woman with mesh erosion after parastomal hernia surgery.The patient,who underwent parastomal hernia repair surgery 3 years prior,presented to the surgery clinic with a complaint of chronic abdominal pain upon resuming defecation through the anus.Three months later,a portion of the mesh was excreted from the patient’s anus and was removed by a doctor.Imaging revealed that the patient’s colon had formed a t-branch tube structure,which was formed by the mesh erosion.The surgery reconstructed the structure of the colon and eliminated potential bowel perforation.CONCLUSION Surgeons should consider mesh erosion since it has an insidious development and is difficult to diagnose at the early stage.
文摘BACKGROUND Vaginal stones are rare with current literature limited to case reports.Vaginal stones are classified as primary or secondary stones.Primary stones form in the vagina when there is urinary stasis.Secondary stones form in the presence of a vaginal foreign body that acts as a nidus for the deposition of urinary salts.Foreign bodies,such as surgical mesh,make vaginal stone formation more likely,particularly in patients with urinary incontinence and conditions that predispose them to urinary calculi formation.CASE SUMMARY A 71-year-old female with a history of sacrocolpopexy,hyperaldosteronism,and urgency urinary incontinence presented with vaginal stone accumulation overlying two areas of vaginal sacrocolpopexy mesh exposure.The vaginal stones were initially removed to permit examination,but the stones reaccumulated at the site of the exposed mesh,later requiring definitive surgical management.CONCLUSION Patients with vaginal mesh exposure and conditions that predispose them to kidney stones are not ideal candidates for expectant management of mesh exposure,particularly if they have coexisting urinary incontinence.These individuals should be counseled about possible vaginal stone accumulation,and surgical management should be considered.
