无线传感器网络隐私保护方法

如何保护隐私信息在无线传感器网络的应用过程中不被泄露,同时能得到较为准确的结果,是无线传感器网络面临的重大挑战。近年来国内外学者对无线传感器网络的隐私保护技术进行了很多研究,从位置隐私保护和数据隐私保护两方面,总结了现有的隐私保护方法,分析了其基本原理和特点。针对现有方法的不足,本文提出了一种能同时保护位置隐私和数据隐私的隐私保护方法,该方法基于多节点幻影路由技术和椭圆曲线同态加密技术。与现有技术相比,该方法具有更好的隐私保护性和更低的能量消耗性。     

~（99m）Tc－MIBI心肌断层显像图像采集方法比较

借助心脏模型和临床研究，探讨了心肌断层显像１８０°采集方式的可行性，并与３６０°资料采集进行了比较。评价参数主要有心肌容积和面积、缺损容积和面积。结果表明；单用心脏模型时，３６０°方式与模型真实值较为接近，而外附体模后，１８０°采集更符合真实值，但相互间均无显著性差异（Ｐ＞０．０５）。３４例冠心病患者心肌病变定量参数３６０°／°与１８０°间或１８０°／６°与１８０°矿间均非常接近；而且１８０°／６°采集时其缺损（病变）／正常心肌比率（０．２３５±０．０４３）较３６０°／６°采集（０．２４９±０．０５７）明显降低（Ｐ＜０．０５），表明前者能更好地分辨病变区。上述结果提示：心肌断层显像时，１８０°采集不但能与３６０°采集一样提供较好的图像，而且能减少图像采集时间，故更具有临床应用价值。     

Precise image fusion standardization for separated modalities using dedicated multimodal heart phantom

The standardization of images derived from different medical modalities should be ensured when image fusion brings essential information and hybrid scanners are not available. The aim of this study was to show that precise image fusion standardization can be obtained using special and unique multimodal heart phantom (MHP) which is compatible with all applied diagnostic methods. MHP was designed and constructed according to International Commission on Radiological Protection reports, scanners requirements and personal experience. Three different types of acquisitions were done: physiological perfusion, myocardial ischaemia and intestines artefacts. The measurements were done using different modalities (single photon emission computed tomography (SPECT), positron emission tomography (PET), MRI, CT) as well as hybrid scanners (PET/CT, SPECT/CT). It was shown that MHP can be used not only for improvement of image fusion standardization protocol but also for verification of proper implementation of the fusion protocol in hybrid scanners.     

A Review on the 3D Printing of Functional Structures for Medical Phantoms and Regenerated Tissue and Organ Applications

Medical models, or “phantoms,” have been widely used for medical training and for doctor-patient interactions. They are increasingly used for surgical planning, medical computational models, algorithm verification and validation, and medical devices development. Such new applications demand high-fidelity, patient-specific, tissue-mimicking medical phantoms that can not only closely emulate the geometric structures of human organs, but also possess the properties and functions of the organ structure. With the rapid advancement of three-dimensional (3D) printing and 3D bioprinting technologies, many researchers have explored the use of these additive manufacturing techniques to fabricate functional medical phantoms for various applications. This paper reviews the applications of these 3D printing and 3D bioprinting technologies for the fabrication of functional medical phantoms and bio-structures. This review specifically discusses the state of the art along with new developments and trends in 3D printed functional medical phantoms (i.e., tissue-mimicking medical phantoms, radiologically relevant medical phantoms, and physiological medical phantoms) and 3D bio-printed structures (i.e., hybrid scaffolding materials, convertible scaffolds, and integrated sensors) for regenerated tissues and organs.     

基于垂线的WSN基站位置隐私保护算法

针对无线传感器网络基站位置隐私保护问题,提出一种基于垂线的基站位置隐私保护算法.根据源节点的位置与坐标轴上一点随机确定一条直线,过基站做直线的垂线,源节点关于该垂线对称的点为第1个预期幻影源节点,使第1个幻影源节点分布具有地理位置多样性.以第1个预期幻影源节点为垂足建立垂线,在该垂线上确定第2个预期幻影源节点,为第2个...     

瓦里安OBI系统锥形束CT图像CT值长期稳定性分析

通过分析7种物质CT值的长期质控检测数据,评估瓦里安机载影像(OBI)系统锥形束CT(CBCT)图像CT值的稳定性。使用Catphan504模体,每月对瓦里安Clinac iX加速器配备的OBI系统进行质控检测,获取高质量头部(HQH)、标准剂量头部(SDH)和盆腔(Pelvis)3种扫描协议下的CBCT图像。使用DoseLab软件,对2017年3月至2018年2月共36个CBCT图像序列进行分析,获取CTP404模块中每种物质的CT值(记为Y)以及与标准CT值的差异(记为ΔY)。对数据进行统计分析,通过计算得到3种扫描协议下7种物质Y值的平均值、标准差和极差以及ΔY的平均值。结果表明:该瓦里安OBI系统CBCT图像CT值在12个月里总体上比较稳定; SDH和Pelvis两种扫描协议适合用于CBCT图像质量的质控和计量检测;HQH扫描协议的CBCT图像中物质CT值与标准CT值的差异,随物质相对电子密度的增加变化较大。     

Study on Design Method of New Operating Phantom for Gamma Irradiation Processing

A new operating phantom was studied for obtaining the true distribution of the radiation field of the gamma irradiation facility and the dose field in the cargo container. An effective and usable simulated radiation field was constructed based on the parameter of the real gamma irradiation facility. The design method for the structure and padding of new operating phantom was proposed. The Monte Carlo method and random filling method (RCS) were adopted to simulate the distribution law of the main factor affecting the dosimetry parameters of the phantom body, such as the dosimeter sleeve material and wall thickness, filler ball size, hollow filler ball size and wall thickness, ball filling method, etc. Under the premise of satisfying the calculation confidence level, the optimization ranges of parameters are as follows: Aluminum tube with wall thickness of 3-5 mm is used as the sleeve, which interferes with the radiation field no more than 4.372 23%; Polypropylene sphere with outer diameter of 1-4 cm, wall thickness of 1.1-11.5 mm, cargo density simulating range of 0.1-0.5 g/cm³, and good material equivalence is selected as the phantom padding, which interferes with the radiation field no more than 9.998 44%; The interference level of the uniform and random filling modes on the radiation field is almost the same, and both are less than 10%. The results show that the current design is feasible and effective, with low investment, more parameters and wider range, and it is suitable for popularization and application.     

DEVELOPMENT OF AN ULTRASOUND PLATFORM FOR THE EVALUATION OF PLANTAR SOFT TISSUE PROPERTIES: A FEASIBILITY STUDY ON SILICONE PHANTOM FEET

A novel ultrasound (US) platform, consisting of an embedded US transducer connected in series with a circular silicone layer, was developed to evaluate the mechanical properties of human plantar tissues in this study. Force exerted by the foot was determined based on the deformation of the silicone layer, which was measured by US. The platform could capture the deformations of both the silicone layer and plantar tissues simultaneously. The stiffness of the plantar tissue was then extracted from the force-deformation curve. To test the feasibility of the US platform, eight phantom feet with different stiffnesses were tested using this new system. The moduli of the phantom feet were also measured by the tissue ultrasound palpation system (TUPS). The results showed that the phantom stiffness determined using the platform was in linear correlation with the corresponding modulus measured by the TUPS (R² = 0.8914). The current system can be improved by using several US transducers to perform multiple measurements at the same time for reliable assessment of human plantar tissues in a non-invasive, convenient, and cost-effective way.     

无线传感器网络节点位置隐私保护研究

为更加深入地研究解决位置隐私保护问题,分析了无线传感器节点位置隐私保护的特点和模型,按照对源节点与对基站以及各自的技术手段分类总结了现有位置隐私保护方案,从方案针对的攻击类型、安全性、效率性能及能耗等方面比较优缺点,并对未来的研究方向进行了展望。