Name: effective analysis of human exposure conditions with body-worn dosimeters in the 2.4 ghz band
Uploaded: 2018-05-02T12:30:00.000+00:00
Duration: 6 min 43 s
Description: Watch this Scientific Journal Video about Effective Analysis of Human Exposure Conditions with Body-worn Dosimeters in the 2.4 GHz Band at JoVE.com

这项工作得到了 "医疗保健智能环境中的电磁特性及其对个人、职业和环境健康的参与" 项目的支持 (DGPY-1285/15、PI14CIII/00056) 和人力资源项目 "西班牙远程医疗发展网络平台" (DGPY-1301/08-1-TS-3), 这两项经费来自研究评估和促进副总干事 (卡洛斯 III 保健研究所)。

建议的议定书遵循卡洛斯 III 健康 Institute´s 人类研究伦理学委员会的指导方针。
1. 电磁环境的外壳选择和控制试验
<ol><li>在卷中选择一个宽敞的机箱, 至少20米3 , 足够大, 使信号衰减在 PEM 记录的数据中明显可见。最好的情况是, 存储模块应该是空的, 尽管这并不是绝对必要的, 因为在用于预测室内外壳16中的 E 字段级别的传播模型中没有考虑到诸如家具之类的小障碍。</li>
	<li>关闭附近设备的 wi-fi 接口, 如移动电话、计算机、笔记本电脑、接入点、等。一个 PEM 的不确定性是辐射源的非特定识别, 即 PEMs 测量每个频率的 E 场, 而不识别每个发射装置。因此, 确保没有 wi-fi 设备在 2.4 GHz 波段运行, 这可能会干扰实验。</li>
	<li>用 pem 提供的特定软件配置一个具有4秒采样率的 PEM。</li>
	<li>将 pem 置于腰部高度, 尽管在这些初步测量中, pem 的磨损位置与此无关。</li>
	<li>启动 pem, 让用户从存储模块的一端走向另一个, 速度约为10厘米/秒. 在用户行走时, 电子字段级别是 PEM 记录的数据。</li>
	<li>使用 PEM 提供的特定软件下载已记录的数据。检查所有记录的数据是否处于 PEM 灵敏度范围的最低限度, 为 2.4 GHz 频带的0.05 伏/米。</li>
	<li>在不同的日子里进行控制测量, 以确保实验的重复性, 并获得结果的一致性, 没有显著的变化, 可能会影响他们的可靠性。 注: 如果在不同的天对控制测试进行了验证, 则可以假定没有 wi-fi 辐射源, 并且记录的数据可能仅仅是由于实验辐射源的贡献。</li>
</ol>2. 固定测量装置的位置
<ol><li>用三 PEMs 在室内的一个外壳内进行初步试验。三 PEMs 的位置将同时进行评估, 以修正 PEM 的位置, 以避免在记录的数据中佩戴者的影响。</li>
	<li>使用每个 PEM 提供的配置软件配置三 PEMs, 采样率为4秒。</li>
	<li>将第一个剂量计放在腰部下部, 身体最大程度地屏蔽 PEM。将第二个剂量计放在腰部高度, 在视线 (洛杉矶) 与辐射源。</li>
	<li>将第三个剂量计放在离用户一米远的地方 (在用户持有的管端到他们的肩上), 在那里它将不受疯牛病的影响。使用长度为1米的纸箱管;例如,地图持有者。三 PEMs 的位置显示在图 1中。</li>
	<li>使用真正的接入点作为辐射源。</li>
	<li>在进行测量之前, 同时打开 PEMs。 注意: 可能会出现不同 PEMs 数据之间的小间隙;这将与结果无关。通常这个缺口约为2或3样本, 样本总数约为300。</li>
	<li>让用户慢慢走向, 然后远离辐射源的速度为10厘米/秒, AP 位于用户的前面和后面, 分别。图 2是实验存储模块的示意图, 并显示预定义路径和 PEMs 位置的方向。</li>
	<li>从 PEMs 下载数据。</li>
</ol>3. 辐射源
<ol><li>对于步骤4中使用的辐射源, 使用与低损耗电缆连接到锥天线的模拟信号发生器。锥天线是覆盖80兆赫到 3 GHz 的频率范围的宽带天线。</li>
	<li>配置模拟信号发生器, 以生成连续信号, 无需调制, 频率为 2437 MHz, 这是 wi-fi 系统最常用的频率之一。</li>
	<li>将生成的信号配置为100兆瓦的等效各向同性辐射功率 (EIRP), 这是欧洲允许的最大 EIRP。</li>
	<li>将锥天线放在机箱一侧的中心 (图 2) 中, 以方便在动态条件下实现实验。</li>
	<li>将锥天线与用户对齐, 以便用户直接面对源, 以便通过非视线 (NLoS) pem 检测记录的数据中的最大疯牛病低估, 而不受疯牛病影响的 pem 的记录级别。</li>
</ol>4. 测量方法
<ol><li>使用两个 PEMs 进行测量。使用每个 PEM 提供的配置软件, 将 PEMs 配置为4秒的采样周期。</li>
	<li>中心的第一个剂量计的背部, 完全 NLoS 与辐射源, 并在那里的身体最大程度地屏蔽 PEM。</li>
	<li>将第二个剂量计放在离用户1米远的距离 (在用户持有的管端到他们的肩上), 以避免人体的影响。这一立场是在步骤2中确定的。两个 PEMs 的位置都在图 3中指示。</li>
	<li>将锥天线置于垂直位置。</li>
	<li>在进行测量之前, 同时打开 PEMs。在步骤2.6 中, 这里的一个小缺口将与结果无关。</li>
	<li>根据图 3中所示的定义路线, 让用户从走廊的另一侧缓慢地向辐射源走, 速度大约为10厘米/秒。当用户正在行走时, PEM 正在记录电子字段数据。</li>
	<li>使用所提供的软件从 PEMs 下载数据。</li>
	<li>重复步骤4.5、4.6 和4.7 与锥天线在水平位置, 为了发现极化类型的影响。</li>
</ol>5. 射线追踪模型
<ol><li>开发或使用基于图像理论的射线追踪软件 (用于分析电磁场传播的射线追踪技术的策略16), 以便通过比较实验和模拟结果。该模型应预测空空间中的 E 场水平, 并允许电磁波与周围环境的相互作用。开发此软件时, 请按照下列步骤操作:<ol>
<li>在不同的阶段开发模型, 以便在垂直和水平平面上生成基于2D 图像生成的3D 路径。计算电子场作为主射线和其他贡献的向量总和, 因为电磁波的反射和衍射在周围环境中的每个评估点注册。计算计算点中的 E 字段值, 作为给定最大数量的与环境的交互后, 源中所有贡献 (射线) 的向量总和。使用存储模块墙壁上的反射数作为输入参数, 以10作为最大值11。</li>
		<li>根据谢尔盖涅耶夫和康斯坦丁努的建议, 采用了圣的启发式衍射系数的扩展, 并在罗德里格斯 et 中使用. 10
</li>
	</ol>
</li>
	<li>作为配置参数, 使用实验设置的功能: 尺寸和材料的介电常数和电导率, 这些物质构成了每一个被测试的外壳的一部分。表 111显示了模拟中使用的材料的电磁参数。与导电材料相关联的反射系数具有较高的振幅。非磁性和非导电介质反射系数的值高到足以影响电子场, 计算为直接射线的主要贡献和衍射和反射的其他贡献的总和。</li>
	<li>介绍了锥天线的结构参数、辐射模式和极化特性。</li>
	<li>作为配置参数引入模拟信号发生器的频率 (2437 兆赫) 和功率 (20 dBm)。</li>
	<li>在正确地包括所有输入之后运行该程序。</li>
	<li>以0.01 伏/米的间隔来量化结果, 目的是模拟 PEM 的工作条件。</li>
	<li>将低于 PEM 灵敏度下限的结果替换为0.05 伏/米的值, 以重现 PEMs 记录的未检测。</li>
</ol>

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Prot. Dosim. 163 (1), 58-69 (2015).</li><li>Zhao, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Attenuation+by+human+bodies+at+26-and+39.5-GHz+millimeter+wavebands.">Attenuation by human bodies at 26-and 39.5-GHz millimeter wavebands.</a> IEEE Antennas Wireless Propag. Lett. 16, 1229-1232 (2017).</li></ol>

作者没有什么可透露的。

对于可靠地收集暴露数据, 而不影响 pem 的不确定性, 这一协议的方面是 pem 的位置。PEM 必须位于1米以外的用户, 以避免低估的影响, 由身体, 并隐含, 以避免大量的不检测在记录的数据。议定书的某些方面可以改变;对拟议技术的修改和局限性进行了如下评估。
所选用于进行实验的测量仪器是 PEM, 它已用于大量的研究, 用于分析户外环境中的 EMF 暴露, 动态地, 在大地理区域24,25, 26。虽然用 PEMs 测量的数据不像频谱分析仪 (SA) 所提供的测量那样准确, 但许多流行病学研究使用 PEMs, 因为它们易于处理和测量率为26, 4 是最小采样周期。在工作中使用的 PEMs 的灵敏度范围的最低限度为0.05 伏/米。更加现代的 PEMs 已经销售了以更宽的灵敏度范围, 0.005 V/米是 2.4 GHz 频带的最低限度, 因此, 当身体屏蔽 PEM 时, 不检测的数量将会降低。然而, 这一事实与本实验无关, 因为获得的结果没有疯牛病的不确定性总是大于0.05 伏/米。还有其他模型的 PEMs 与较低的取样周期, 但本实验中使用的模型被选择, 因为它是容易携带的身体, 在腰部高度, 在那里的身体是最大的屏蔽 PEM。
在初步实验中, 在 2.4 GHz 的 wi-fi 频段使用 wi-fi AP 作为辐射源。在评估 AP 与 SA 发出的电源后, 进行了检查以确认信息数据包未连续传输, 并且有一段时间没有传输27,28。因此, 在 PEMs 的检测极限 (0.05 伏/米) 以下, 很大一部分 RF EMF 水平。最低 wi-fi AP 工作周期由信标信号固定, 约为0.01%。同时, 连续信号的上限周期限制为 100%, 重现了最坏情况下的曝光条件, 同时避免了非检测的不确定性。由于这个原因, 信号发生器和锥天线被用作辐射源, 以产生连续波100兆瓦的功率, 在 wi-fi 频率, 并没有调制。
利用基于图像理论的射线追踪软件, 预测了四个室内罩中的 E 场水平。使用另一种实验技术 (如 SA 与探针) 进行的实验结果的评估尚未被考虑, 因为目的是分析疯牛病和其他 pem 不确定性的影响, 而不是质子交换膜作为另一种操作的能力。测量装置。图像理论的局限性是由于非理想的环境条件, 即当反射面不薄、平坦或平面时。当环境条件非理想时, 传播模型结果收集反射系数的不确定性。当表面受到限制时, 可以消除不与它们拦截的光线。随着反射次数的增加, 菲涅尔椭球的大小增加, 近似值更差。然而, 来自多个反射的光线会更弱, 对最终结果的影响也较小。
采用天真的方法来解决非检测的不确定性问题。此方法由灵敏度范围限制下的值替换为较低的检测限制29。还存在其他方法来纠正未检测的不确定性, 并替换已记录的数据。基于顺序统计 (ROS) 方法的稳健回归预测了未被发现的值, 考虑到它们遵循对数正态分布。其他方法可以应用于数据, 但估计总是出现误差幅度。采用较低检测限的替代方法已被使用, 因为用固定值代替可识别不检测。此外, CDFs 的这一地区在分析的几个案件中没有出现相关的差异。
由于 PEMs 设计为用户佩戴, 佩戴者的存在是造成这种不确定性的原因, 因此人体的阴影效应的不确定性必须得到特别的关注。此外, 对疯牛病的低估可能会导致不检测的增加。在身体的不同部位戴几个 PEMs, 也可以避免疯牛病30,31;将两个 PEMs 位于正文的另一侧的记录的数据平均导致较小的低估, 并且比单个 PEM5的记录数据更小的不确定性。另一种替代方法是在解释暴露数据时考虑到疯牛病对暴露水平的改变, 并应用适当的矫正因素。然而, 这些必须单独地确定在活动和环境的作用, 并且是非常复杂的正确地申请。此外, 本研究中所采用的技术还提出了一种切实可行的方法来避免只需要单一 PEM 的疯牛病, 从而避免了数据的处理。
考虑到移动技术的进步和未来 5G (第五代) 无线电系统中人体衰减的兴趣32, 本研究提出的技术可用于评估人类对新一代网络的接触情况。避免上述不确定性。

近年来, 无线局域网 (WLAN) 的使用变得越来越普遍。无线技术已成为传统固定访问的替代方案, 因此, 在住宅、职业和公共区域安装了大量接入点 (AP)1,2。这大量的 AP 和个人通信设备导致了对与电磁场 (EMF) 曝光相关的可能风险的极大兴趣3。
个人 exposimeters (PEMs) 是用于测量个人暴露的便携式设备, 通常用于流行病学领域。在电磁场测量中使用 PEMs 时, 有几项研究发现了不确定性。这些发现显示了 PEMs 对获得的结果4的可靠性水平的影响。提出了一些解决方案, 以尽量减少这些不确定因素的影响, 例如, 良好的 PEM 磨损技术、较小的取样间隔和足够长度的测量5。
某些作者发表了关于在曝光测量中考虑责任因素 (或工作周期) 的重要性的著作。在现实世界中, wi-fi 设备从不以全负荷周期传输。wi-fi 信号包括间歇性的射频 (RF) 能量的爆发和没有任何传输的周期。因此, 有很大比例的报告暴露测量是非常低的, 往往低于灵敏度范围, 并记录为非检测 PEMs。通过理论计算6, 一些工作建议使用因素来获取实际值。
人体阴影效应的不确定性已经得到了特别的关注, 因为 PEMs 的设计是由用户佩戴的, 佩戴者的存在导致了记录数据的不确定性。知识和量化的疯牛病帮助提供正确的解释暴露数据, 没有它, 将有必要执行严格的测量程序。疯牛病可以避免通过佩戴几个 PEMs, 位于人体的不同部位7, 或通过对获得的结果应用校正因子5,9,10,11,12.同时, 在其他情况下, 在使用钢瓶13时, 该机构已被替换为模拟技术。一些工程建议实施特定的测量技术, 以避免人体的影响13。本研究提出了一种测量方法, 它避免了人体在实际室内外壳中的影响, 而不操作曝光数据。
PEMs 的一个特点是辐射源的不确定。PEMs 测量某些频段的电场 (E 场) 电平, 但如果多个源或器件以相同的频率辐射, 则 PEM 测量 E 场水平而不确定每个特定源的贡献。
因此, 由于这些 PEMs 记录数据的不确定性来源, 暴露水平分析要求对电磁场水平进行实验评估和数值预测的程序, 以获得可靠的结果。这项工作提出了一个适当的方法, 可以用来评估暴露在电子领域 (2.4 GHz 频率) 在室内罩。使用这种方法, 前面提到的不确定因素由于疯牛病的低估, 不检测造成的高估, 和不可靠的辐射源的不确定。这种增强的可靠性意味着使用所提出的方法获得的数据在 EMF 暴露的不利条件情况下提供了上界。在国家和国际卫生保护标准中确立的暴露限制是为不受干扰的 EMF 数据定义的, 任何效果或代理都不改变。建议的实验程序在法规测试遵从性方面是适当的, 因为在记录的数据中避免了不确定性, 提供了可与暴露阈值进行对比的可靠信息。
在实施了实验协议后, 将所得结果与欧洲立法中的阈值和建议的暴露价值进行了比较。这样做是为了检查在典型的室内环境中, 由于 wi-fi 系统的电动势暴露的法规遵从性, 这反过来又代表了常见的工作场所环境。目前, wi-fi 频率为 2.4 GHz 是其中一个通信带, 其中有更广泛的可利用的数据在公众的接触。这一特定波段的政治利益是由于人们普遍担心, 在敏感的环境中, 诸如医疗保健中心、医院、学校、甚至家庭设置15。
这项工作提出了一个协议, 以提供不受干扰的测量的电子场暴露条件, 避免与使用 PEMs 有关的不确定性。这项工作的目的是改善使用 PEMs 作为测量设备的合规性测试。

<table><tbody><tr><td>Personal exposimeter</td><td>SATIMO</td><td>EME SPY 121/100</td><td>Worn personal exposimer to log expsure data</td></tr><tr><td>Personal exposimeter</td><td>ANTENNESSA</td><td>EME SPY 121/120</td><td>Worn personal exposimer to log expsure data</td></tr><tr><td>Wi-Fi Access Point</td><td>CISCO</td><td>Aironet 1130</td><td>Wi-Fi access point, vertial polarization&amp;nbsp;</td></tr><tr><td>Analog Signal Generator&amp;nbsp;</td><td>AGILENT</td><td>N5181A MXG&amp;nbsp;</td><td>Analog Signal Generator&amp;nbsp;</td></tr><tr><td>Precision Conical Dipole&amp;nbsp;</td><td>SEIBERSDORF&amp;nbsp;</td><td>PCD 8250</td><td>Broadband antenna 80 MHz - 3 GHz. Dipole-like radiation pattern that is omnidirectional in the horizontal plane</td></tr><tr><td>Cable</td><td>ROHDE &amp;amp; SCHWARZ</td><td>LARG-214/U&amp;nbsp;</td><td>Low loss cable</td></tr></tbody></table>

effective analysis of human exposure conditions with body-worn dosimeters in the 2.4 ghz band

提出了一个定义良好的实验程序, 以评估最坏情况下的最大暴露条件, 同时避免使用个人 exposimeters (PEMs) 作为测量设备所造成的不确定性: 体影效应 (疯牛病)、灵敏度范围有限, 辐射源不确定。测量和模拟了几个室内罩中的电磁场暴露水平的上界。该研究的频率为 2.4 GHz, 因为它是室内通信中最常用的波段。虽然记录的价值远远低于国际非电离辐射保护委员会 (ICNIRP) 的参考水平, 但特别需要在特别敏感的环境中提供可靠的暴露水平。在电磁场 (EMF) 暴露方面, 国家和国际卫生保护标准中规定的限制不受干扰的暴露条件;这是, 对于真实和客观的曝光数据, 没有被改变的任何方式。

选择了四个不同尺寸的室内罩进行实验测量, 其卷是 63 m3 (尺寸 12 x 1.26/3 x 2.45 m), 162 m3 (27.15 x 1.93 x 3.1 m), 57 m3 (9 x 2.56 x 2.47 m) 和 63 m3 (10 x2.56 x 2.47 m)。第一个存储模块的宽度不恒定。在第一和第二个存储模块中, 预定义路径的长度为 12 m。在第三和第四个存储模块中, 预定义路径的长度分别为最大维度, 即9和 10 m。影响疯牛病的一个因素是室内外壳的材料类型, 因为接触导电材料的环境中的暴露水平会增加。具体地说, 我们使用的外壳是由非反光材料组成的。在这种情况下, 疯牛病变得相关, 因为在疯牛病下记录的反射射线比导电材料的情况弱。
在初始阶段获得的结果汇总在图 4中, 它将记录的数据与三 PEMs (一个在后面, 另一个在前面, 第三个位于1米之外) 进行比较, 而用户正向 AP 方向移动. E 字段与辐射源在洛杉矶被磨损的 pem 记录下来的水平非常相似, 在与辐射源相关的1米以外的 pem 记录的位置, 尽管很明显, 与身体接触的 pem 注册了较低的级别7.对于这两种路径, 在阴影区中磨损的 PEMs 所收集的水平比在洛杉矶穿的和不穿的 PEMs 收集到的数据要低。
PEMs 在每个位置记录的 E 字段级别在两个路径中都非常相似, 但存在一些差异。考虑到远离 AP 的路径, 有限差分时域 (FDTD) 分析表明, 入射波可以在身体使用者周围弯曲, 到达相反一侧磨损的 pem, 甚至在1米以外的 pem, 在那里疯牛病较弱。这种效应在室内环境中更为重要, 因为身体的阴影区域很小。这就是为什么 PEMs 所记录的数据在两条路径中与用户距离1米的原因类似于暴露的条件。
对于磨损的 PEMs, 耦合体的影响会导致 PEM 辐射模式 (RD) 的失真, 随后影响记录的数据。然而, 由于在洛杉矶的 PEMs 的记录数据往往相似, 但低于记录的数据由 PEMs 位于1米远, 它可以得出结论, 在洛杉矶的情况下, 人体有一个微不足道的影响相比, 由于疯牛病的扭曲。
如图 4所示, 在所有 PEM 位置中, 电子字段级别对 AP 的路径趋于较低, 用户位置位于辐射源的正面。在 GHz 范围内, 整个人体内的 sar (sarWB) 在正面入射平面波下略高, 因为人的形态学: 较大的皮肤面积和粗糙的表面 (脚趾、脚、下巴、脸部) 都包含在身体的正面。电子场可以有效地影响这些小体部分, 它们是 GHz 范围17中典型的峰值 SAR 位置。
AP 的传输是不连续的, 因此 PEMs 中的许多记录级别都没有达到较低的灵敏度阈值, 而非检测的数量变得太大。被视为可接受的未检测百分比低于 60%, 替换可能是可接受的, 如 Helsel18所解释的那样。尽管在图 4中显示的结果中, 未检测到的最大数目是 50%, 接近接受级别 60%, 但与 AP 的测试是可靠的, 足以确认 1 m 是避免疯牛病的最佳距离。
因此, PEM 位于离用户1米处的位置是最佳的, 可以记录可靠的暴露在电子场上的水平, 不受身体影响所造成的低估的影响。考虑到这些考虑因素, 在四个选定的环境中, 在水平和垂直偏振中进行了测量, 并遵循了上一节中描述的方法: 两个 PEMs, 一个由用户佩戴, 在NLoS, 第二个位于1米以外的用户和在洛杉矶与辐射源。
图 5和图 6显示第一个和第二个存储模块中的 E 字段级别, 以半对数刻度和两个偏振沿路径指向由锥天线和信号发生器组成的辐射源。疯牛病的低估直接取决于环境的大小: 在第二个外壳中低估的程度更大, 而在室外, 而不是室内的外壳中, 效果更大。值得注意的是, 由于主辐射源的偏振类型影响了疯牛病的影响程度, 因此疯牛病的低估比水平极化大。为了避免在阴影情况下没有对记录的数据进行进一步处理的情况下的高数量的检测, 两个偏振中的测量都在第二个机箱中以 25 dBm (316.12 兆瓦) 的传输功率重复。图 6将偏振中的 rescaled 度量值显示为 20 dB, 并以半对数刻度来感知阴影情况下的 E 场级别。在水平极化的情况下, 尽管在垂直极化中, 这种非检测已被避免, 但百分比仍然相当可观。
在测试条件下的所有外壳中都进行了两偏振的测量。图 5显示了第一个存储模块的结果, 阴影数据在两个偏振中都相似。但是, 从第二个存储模块的结果中, 最大一个 (如图 6所示), 两个偏振中的阴影数据的差异比图 5更显著。
为了量化每个存储模块中两个偏振中的阴影数据的差异,表 2提供了偏振因子 (PF), 该系数与两个偏振中的非阴影和阴影数据的比率之间的比值有关, 如 (1) 所示:
<img alt="Equation 1" src="/files/ftp_upload/56525/56525eq1v2.jpg">(1)
从表 2可以推断, 存储模块越大, 在非阴影和阴影数据之间发现垂直极化的差异就越大。这项研究的结果表明, 垂直极化比水平极化有更显著的低估, 因为对于2100兆赫左右的频率, 四肢和头部/躯干的局部 SAR 的垂直偏振度较高, 处于站立位置, 当波浪撞击身体从前面或后面17。此外, 用户与波长相比并不小, 因此垂直极化在入射波24的吸收方面处于最坏的水平。当人体的主轴与电场矢量平行时 (当锥天线的极化垂直时发生), 人体的特定吸收率 (SAR) 达到最大值19。理论上, 垂直极化波在很大程度上被人体屏蔽, 与水平极化波相比。这是由于在垂直极化中, E 场振荡平行于佩戴者的长轴8。由于天线的极化是疯牛病中的一个关键因素, 所以正确的极化是垂直的, 以便检测用户存在对磨损的 PEM 和 NLoS20的测量的最大影响。
在测试条件下的四存储模块中获得的暴露级别以半对数刻度显示在图 7中。仿真结果与预定义路线的每一点的测量一起显示, 表明两种数据类型在与辐射源的距离上有相同的变化。
表 3分别汇总了测量的和模拟的电子字段级别。对于每个室内外壳, 提供平均值、标准偏差和最大值和最小数值。值得注意的是实验和模拟数据的统计值之间的相似性。通过柯尔莫哥洛夫斯米尔诺夫 (KS) 测试获得的p值, 也检查了每对实验和模拟数据系列之间的相似性。p 值显示在表 3中。p-值总是大于0.05 的意义级别, 因此每对实验数据系列和模拟序列之间有足够的匹配。此外, 还通过 KS 测试确定了每个系列的累积分布函数 (偏振), 无论是实验还是模拟, 都始终遵循对数正态分布的统计分布。
图 7显示了用于测试的室内外壳中测量和模拟的数据, 以及是否符合基于 ICNIRP 的欧洲立法规定的阈值, 这构成了目前许多暴露标准的基础。在全球范围内适用于一般、国内和职业环境。就一般人口而言, 在 2.4 GHz 频率下接触非电离辐射的限制为61伏/米。在 ICNIRP 中建立的61伏/米的价值不是人类暴露的限制性最高的限制。其他标准存在于世界各地: 在北美, IEEE 建立了限制性限制: 66.7 伏/米为不受控制的环境, 相当于一般公众在 ICNIRP。此外, 东欧也存在限制性更强的规定, 如俄罗斯的情况, 即对一般人口的严格限制为3.14 伏/米。在图 7中, 与 ICNIRP 阈值相比较的测量不受 PEM 的不确定性的影响, 这在提取的结论中提供了有关法规遵从性的可靠性。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/56525/56525fig1.jpg"> 图 1: 在实验期间 PEMs 的位置.
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/56525/56525fig2.jpg"> 图 2: 预定义的控制测试路径, 朝向和远离辐射源, 以及三剂量计的位置.
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/56525/56525fig3.jpg"> 图 3: 在四机箱中对辐射源和剂量计的位置执行的测量的预定义路径.显示第一和第二个机箱内测试区域的长度, 12 m。
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/56525/56525fig4.jpg"> 图 4: CDFs 三 PEMs 在不同位置的结果.结果显示1米远, 在洛杉矶的用户佩戴, 并佩戴的用户在 NLoS 为两个预定义的路径-朝向和远离辐射源。
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/56525/56525fig5.jpg"> 图 5: 在 63 m3第一个存储模块中获得的实验数据.数据显示为 (a) 垂直和 (b) 水平极化, 与和没有身体影响, 以100兆瓦的传输力量。这些数据显示在用户向源方向走的时候, PEM 记录的样本数的函数。结果以半对数刻度显示。
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/56525/56525fig6.jpg"> 图 6: 在 162 m 中获得的实验数据3第二个存储模块。数据显示为 (a) 垂直和 (b) 水平极化, 具有和不具身体影响, 传输功率为 25 dbm (316.12 兆瓦), rescaled 为 20 dbm (100 兆瓦)。数据显示为由 PEM 记录的样本数的函数, 而用户正向源方向走。结果以半对数刻度显示。
<img alt="Figure 7" class="xfigimg" src="/files/ftp_upload/56525/56525fig7.jpg"> 图 7: 测量和模拟垂直极化的 E 场的水平.级别 (a) 首先显示 (63 m3), (b) 第二个 (162 m3), (c) 第三个 (57 m3) 和 (d) 第四 (63 m3) 存储模块。这些水平显示为一般人口和 2.4 GHz 波段的61伏/米 ICNIRP 暴露限制百分比的函数。数据显示为由 PEM 记录的样本数的函数, 而用户正向源方向走。
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody>
<tr>
<td rowspan="2">材料</td>
			<td>电导 率</td>
			<td>相对</td>
		</tr>
<tr>
<td>(S/米)</td>
			<td>介电常数</td>
		</tr>
<tr>
<td>天花板–纸板</td>
			<td>0.001</td>
			<td>2。5</td>
		</tr>
<tr>
<td>地板–大理石</td>
			<td>0.00022</td>
			<td>7</td>
		</tr>
<tr>
<td>侧壁</td>
			<td>0.005</td>
			<td>3</td>
		</tr>
<tr>
<td>金属</td>
			<td>100</td>
			<td>3</td>
		</tr>
<tr>
<td>玻璃</td>
			<td>1E-10</td>
			<td>6</td>
		</tr>
<tr>
<td>木材</td>
			<td>0.0006</td>
			<td>2</td>
		</tr>
</tbody></table>表 1: 模拟中使用的电磁参数。
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody>
<tr>
<td rowspan="2">外壳</td>
			<td>体积</td>
			<td>极化</td>
		</tr>
<tr>
<td>(m3)</td>
			<td>因素</td>
		</tr>
<tr>
<td>1</td>
			<td>63</td>
			<td>1.0635</td>
		</tr>
<tr>
<td>2</td>
			<td>162</td>
			<td>1.3325</td>
		</tr>
<tr>
<td>3</td>
			<td>57</td>
			<td>1.0235</td>
		</tr>
<tr>
<td>4</td>
			<td>63</td>
			<td>1.0590</td>
		</tr>
</tbody></table>表 2:每个存储模块的极化系数, 计算为非阴影数据和阴影的方法之间的关系.外壳的大小被表明。
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody>
<tr>
<td rowspan="2">外壳</td>
			<td>大小</td>
			<td colspan="2">平均值 (V/米)</td>
			<td colspan="2">性病 (V/米)</td>
			<td colspan="2">最大 (V/米)</td>
			<td colspan="2">最小 (V/米)</td>
			<td>p 值</td>
			<td>p 值</td>
		</tr>
<tr>
<td>(m3)</td>
			<td>进出口</td>
			<td>Sim</td>
			<td>进出口</td>
			<td>Sim</td>
			<td>进出口</td>
			<td>Sim</td>
			<td>进出口</td>
			<td>Sim</td>
			<td>PolV</td>
			<td>PolH</td>
		</tr>
<tr>
<td>1</td>
			<td>63</td>
			<td>0.27</td>
			<td>0.29</td>
			<td>0.17</td>
			<td>0.22</td>
			<td>1.45</td>
			<td>1.36</td>
			<td>0.05</td>
			<td>0.05</td>
			<td>0.7296</td>
			<td>0.8924</td>
		</tr>
<tr>
<td>2</td>
			<td>162</td>
			<td>0.22</td>
			<td>0.24</td>
			<td>0。2</td>
			<td>0.23</td>
			<td>1.47</td>
			<td>1.41</td>
			<td>0.05</td>
			<td>0.05</td>
			<td>0.4579</td>
			<td>0.3802</td>
		</tr>
<tr>
<td>3</td>
			<td>57</td>
			<td>0.25</td>
			<td>0.26</td>
			<td>0.15</td>
			<td>0.17</td>
			<td>1.18</td>
			<td>0。9</td>
			<td>0.05</td>
			<td>0.05</td>
			<td>0.3740</td>
			<td>0.3452</td>
		</tr>
<tr>
<td>4</td>
			<td>63</td>
			<td>0.23</td>
			<td>0.25</td>
			<td>0.20</td>
			<td>0.21</td>
			<td>1.24</td>
			<td>1.18</td>
			<td>0.05</td>
			<td>0.05</td>
			<td>0.4679</td>
			<td>0.4263</td>
		</tr>
</tbody></table>表 3:主要统计值的实验和模拟结果在四罩下的测试条件下, 垂直和水平极化.外壳的大小被表明。

Watch this Scientific Journal Video about Effective Analysis of Human Exposure Conditions with Body-worn Dosimeters in the 2.4 GHz Band at JoVE.com

Effective Analysis of Human Exposure Conditions with Body-worn Dosimeters in the 2.4 GHz Band

2.4 GHz 波段人体磨损剂量计暴露条件的有效分析

本研究描述了一种测量 2.4 GHz 波段暴露水平的协议, 避免了使用个人 exposimeters 作为测量装置所造成的不确定性。应考虑到暴露水平的这些变化, 特别是在符合性测试中, 从非扰动数据中定义曝光限制。

A well-defined experimental procedure is put forward to evaluate maximum exposure conditions in a worst-case scenario whilst avoiding the uncertainties ...

effective-analysis-human-exposure-conditions-with-body-worn

Research

JoVE Journal

Engineering

7.0K 次观看.  Instituto de Salud Carlos III. 本研究描述了一种测量 2.4 GHz 波段暴露水平的协议, 避免了使用个人 exposimeters 作为测量装置所造成的不确定性。应考虑到暴露水平的这些变化, 特别是在符合性测试中, 从非扰动数据中定义曝光限制。

视频: Effective Analysis of Human Exposure Conditions with Body-worn Dosimeters in the 2.4 GHz Band

Expedited Radiation Biodosimetry by Automated Dicentric Chromosome Identification (ADCI) and Dose Estimation

Biological radiation dose can be estimated from dicentric chromosome frequencies in metaphase cells. Performing these cytogenetic dicentric chromosome assays is traditionally a manual, labor-intensive process not well suited to handle the volume of samples which may require examination in the wake of a mass casualty event. Automated Dicentric Chromosome Identifier and Dose Estimator (ADCI) software automates this process by examining sets of metaphase images using machine learning-based image processing techniques. The software selects appropriate images for analysis by removing unsuitable images, classifies each object as either a centromere-containing chromosome or non-chromosome, further distinguishes chromosomes as monocentric chromosomes (MCs) or dicentric chromosomes (DCs), determines DC frequency within a sample, and estimates biological radiation dose by comparing sample DC frequency with calibration curves computed using calibration samples. This protocol describes the usage of ADCI software. Typically, both calibration (known dose) and test (unknown dose) sets of metaphase images are imported to perform accurate dose estimation. Optimal images for analysis can be found automatically using preset image filters or can also be filtered through manual inspection. The software processes images within each sample and DC frequencies are computed at different levels of stringency for calling DCs, using a machine learning approach. Linear-quadratic calibration curves are generated based on DC frequencies in calibration samples exposed to known physical doses. Doses of test samples exposed to uncertain radiation levels are estimated from their DC frequencies using these calibration curves. Reports can be generated upon request and provide summary of results of one or more samples, of one or more calibration curves, or of dose estimation.

Expedited Radiation Biodosimetry by Automated Dicentric Chromosome Identification ADCI and Dose Estimation

The cytogenetic dicentric chromosome (DC) assay quantifies exposure to ionizing radiation. The Automated Dicentric Chromosome Identifier and Dose Estimator software accurately and rapidly estimates biological dose from DCs in metaphase cells. It distinguishes monocentric chromosomes and other objects from DCs, and estimates biological radiation dose from the frequency of DCs.

自动 Dicentric 染色体识别 (ADCI) 和剂量估计加速辐射剂量

Biological radiation dose can be estimated from dicentric chromosome frequencies in metaphase cells. Performing these cytogenetic dicentric chromosome ...

科研

遗传学

Evaluation of a Smartphone-based Human Activity Recognition System in a Daily Living Environment

An evaluation method that includes continuous activities in a daily-living environment was developed for Wearable Mobility Monitoring Systems (WMMS) that attempt to recognize user activities. Participants performed a pre-determined set of daily living actions within a continuous test circuit that included mobility activities (walking, standing, sitting, lying, ascending/descending stairs), daily living tasks (combing hair, brushing teeth, preparing food, eating, washing dishes), and subtle environment changes (opening doors, using an elevator, walking on inclines, traversing staircase landings, walking outdoors). 
To evaluate WMMS performance on this circuit, fifteen able-bodied participants completed the tasks while wearing a smartphone at their right front pelvis. The WMMS application used smartphone accelerometer and gyroscope signals to classify activity states. A gold standard comparison data set was created by video-recording each trial and manually logging activity onset times. Gold standard and WMMS data were analyzed offline. Three classification sets were calculated for each circuit: (i) mobility or immobility, ii) sit, stand, lie, or walking, and (iii) sit, stand, lie, walking, climbing stairs, or small standing movement. Sensitivities, specificities, and F-Scores for activity categorization and changes-of-state were calculated.
The mobile versus immobile classification set had a sensitivity of 86.30% &#177; 7.2% and specificity of 98.96% &#177; 0.6%, while the second prediction set had a sensitivity of 88.35% &#177; 7.80% and specificity of 98.51% &#177; 0.62%. For the third classification set, sensitivity was 84.92% &#177; 6.38% and specificity was 98.17 &#177; 0.62. F1 scores for the first, second and third classification sets were 86.17 &#177; 6.3, 80.19 &#177; 6.36, and 78.42 &#177; 5.96, respectively. This demonstrates that WMMS performance depends on the evaluation protocol in addition to the algorithms. The demonstrated protocol can be used and tailored for evaluating human activity recognition systems in rehabilitation medicine where mobility monitoring may be beneficial in clinical decision-making.

A standardized evaluation method was developed for Wearable Mobility Monitoring Systems (WMMS) that includes continuous activities in a realistic daily living environment. Testing with a series of daily living activities can decrease activity recognition sensitivity; therefore, realistic testing circuits are encouraged for valid evaluation of WMMS performance.

在日常生活环境评价一个智能手机为基础的人类活动识别系统

An evaluation method that includes continuous activities in a daily-living environment was developed for Wearable Mobility Monitoring Systems (WMMS) that ...

行为学

An Automated Microscopic Scoring Method for the &#947;-H2AX Foci Assay in Human Peripheral Blood Lymphocytes

Ionizing radiation is a potent inducer of DNA damage and a well-documented carcinogen. Biological dosimetry comprises the detection of biological effects induced by exposure to ionizing radiation to make an individual dose assessment. This is pertinent in the framework of radiation emergencies, where health assessments and planning of clinical treatment for exposed victims are critical. Since DNA double strand breaks (DSB) are considered to be the most lethal form of radiation-induced DNA damage, this protocol presents a method to detect DNA DSB in blood samples. The methodology is based on the detection of a fluorescent labelled phosphorylated DNA repair protein, namely, &#947;-H2AX. The use of an automated microscopy platform to score the number of &#947;-H2AX foci per cell allows a standardized analysis with a significant decrease in the turn-around time. Therefore, the &#947;-H2AX assay has the potential to be one of the fastest and sensitive assays for biological dosimetry. In this protocol, whole blood samples from healthy adult volunteers will be processed and irradiated in vitro in order to illustrate the usage of the automated and sensitive &#947;-H2AX foci assay for biodosimetry applications. An automated slide scanning system and analysis platform with an integrated fluorescence microscope is used, which allows the fast, automatic scoring of DNA DSB with a reduced degree of bias.

This protocol presents the slide preparation and automated scoring of the &#947;-H2AX foci assay on peripheral blood lymphocytes. To illustrate the method and sensitivity of the assay, isolated lymphocytes were irradiated in vitro. This automated method of DNA DSB detection is useful for fast and high-throughput biological dosimetry applications.

一种人外周血淋巴细胞γ-H2AX病灶测定的自动显微镜评分方法

Ionizing radiation is a potent inducer of DNA damage and a well-documented carcinogen. Biological dosimetry comprises the detection of biological effects ...

癌症研究

Visualizing Field Data Collection Procedures of Exposure and Biomarker Assessments for the Household Air Pollution Intervention Network Trial in India

Here, we present a visual representation of standard procedures to collect population-level data on personal exposures to household air pollution (HAP) from two different study sites in a resource-constrained setting of Tamil Nadu, India. Particulate matter PM2.5 (particles smaller than 2.5 microns in aerodynamic diameter), carbon monoxide (CO), and black carbon (BC) were measured in pregnant mothers (M), other adult women (OAW), and children (C) at various times over a 4 year period. In addition, stove usage monitoring (SUMs) with data-logging thermometers and ambient measurements of air pollution were carried out. Furthermore, the feasibility of collecting biological samples (urine and dried blood spots [DBSs]) from study participants at the field sites was successfully demonstrated. Based on findings from this and earlier studies, the methods used here have enhanced the data quality and avoided issues with household air pollution and biological sample collection in resource-constrained situations. The procedures established may be a valuable educational tool and resource for researchers conducting similar air pollution and health studies in India and other low- and middle-income countries (LMICs).

We detail the consistent, high-quality procedures used throughout air and biological sampling processes at Indian field sites during a large randomized controlled trial. Insights gathered from the oversight of applications of innovative technologies, adapted for exposure assessment in rural regions, enable better field data collection practices with more reliable outcomes.

可视化印度家庭空气污染干预网络试验的暴露和生物标志物评估的现场数据收集程序

Here, we present a visual representation of standard procedures to collect population-level data on personal exposures to household air pollution (HAP) ...

环境科学

A Cross-Disciplinary and Multi-Modal Experimental Design for Studying Near-Real-Time Authentic Examination Experiences

Over the past ten years, research into students&#39; emotions in educational environments has increased. Although researchers have called for more studies that rely on objective measures of emotional experience, limitations on utilizing multi-modal data sources exist. Studies of emotion and emotional regulation in classrooms traditionally rely on survey instruments, experience-sampling, artifacts, interviews, or observational procedures. These methods, while valuable, are mainly&#160;dependent on participant or observer subjectivity and is limited in its authentic measurement of students&#39; real-time performance to a classroom activity or task. The latter, in particular, poses a stumbling block to many scholars seeking to objectively measure emotions and other related measures in the classroom, in real-time.
The purpose of this work is to present a protocol to experimentally study students&#39; real-time responses to exam experiences during an authentic assessment situation. For this, a team of educational psychologists, engineers, and engineering education researchers designed an experimental protocol that retained the limits required for accurate physiological sensor measurement, best-practices of salivary collection, and an authentic testing environment. In particular, existing studies that rely on physiological sensors are conducted in experimental environments that are disconnected from educational settings (e.g., Trier Stress Test), detached in time (e.g., before or after a task), or introduce analysis error (e.g., use of sensors in environments where students are likely to move). This limits our understanding of students&#39; real-time responses to classroom activities and tasks. Furthermore, recent research has called for more considerations to be covered around issues of recruitment, replicability, validity, setups, data cleaning, preliminary analysis, and particular&#160;circumstances (e.g., adding a variable in the experimental design) in academic emotions research that relies on multi-modal approaches.

An experimental design was developed to investigate the real-time influences of an examination experience to assess the emotional realities students experience in higher education settings and tasks. This design is the result of a cross-disciplinary (e.g., educational psychology, biology, physiology, engineering) and multi-modal (e.g., salivary markers, surveys, electrodermal sensor) approach.

用于研究近实时真实考试体验的跨学科、多模式实验设计

Over the past ten years, research into students&#39; emotions in educational environments has increased. Although researchers have called for more studies ...

<meta charset="utf8"></head><body>军事武器训练中爆炸波模拟的虚拟场景生成

Generation of Warfighter Avatars from Weapon Training Scene Images for Blast Exposure Simulations

Military personnel involved in weapon training are subjected to repeated low-level blasts. The prevailing method of estimating blast loads involves wearable blast gauges. However, using wearable sensor data,&#160;blast loads to the head or other organs&#160;cannot be accurately estimated without knowledge of the service member&#39;s body posture. An image/video-augmented complementary experimental-computational platform for conducting safer weapon training was developed. This study describes the protocol for the automated generation of weapon training scenes from video data for blast exposure simulations. The blast scene extracted from the video data at the instant of weapon firing involves the service member body avatars, weapons, ground, and other structures. The computational protocol is used to reconstruct service members&#39; positions and postures using this data. Image or video data extracted from service member body silhouettes are used to generate an anatomical skeleton and the key anthropometric data. These data are used to generate the 3D body surface avatars segmented into individual body parts and geometrically transformed to match extracted service member postures. The final virtual weapon training scene is used for 3D computational simulations of weapon blast wave loading on service members. The weapon training scene generator has been used to construct 3D anatomical avatars of individual service member bodies from images or videos in various orientations and postures. Results of the generation of a training scene from shoulder-mounted assault weapon system and mortar weapon system image data are presented. The Blast Overpressure (BOP) tool uses the virtual weapon training scene for 3D simulations of blast wave loading on the service member avatar bodies. This paper presents 3D computational simulations of blast wave propagation from weapon firing and corresponding blast loads on service members in training.

<meta charset="utf8"></head><body>作者聚焦：基于摄像头的自动化系统的开发，用于军事训练中的实时爆炸超压监测和 TBI 风险评估

A computational framework was developed to automatically reconstruct virtual scenes comprising 3D avatars of soldiers using image and/or video data. The virtual scenes help estimate blast overpressure exposure during weapon training. The tool facilitates a realistic representation of human posture in blast exposure simulations in various scenarios.

从武器训练场景图像生成战士头像，用于爆炸曝光模拟

Military personnel involved in weapon training are subjected to repeated low-level blasts. The prevailing method of estimating blast loads involves ...

工程学

Diffuse Optical Spectroscopy for the Quantitative Assessment of Acute Ionizing Radiation Induced Skin Toxicity Using a Mouse Model

Acute skin toxicities from ionizing radiation (IR) are a common side effect from therapeutic courses of external beam radiation therapy (RT) and negatively impact patient quality of life and long term survival. Advances in the understanding of the biological pathways associated with normal tissue toxicities have allowed for the development of interventional drugs, however, current response studies are limited by a lack of quantitative metrics for assessing the severity of skin reactions. Here we present a diffuse optical spectroscopic (DOS) approach that provides quantitative optical biomarkers of skin response to radiation. We describe the instrumentation design of the DOS system as well as the inversion algorithm for extracting the optical parameters. Finally, to demonstrate clinical utility, we present representative data from a pre-clinical mouse model of radiation induced erythema and compare the results with a commonly employed visual scoring. The described DOS method offers an objective, high through-put evaluation of skin toxicity via functional response that is translatable to the clinical setting.

We present a diffuse optical spectroscopic (DOS) approach that provides quantitative optical biomarkers of skin response to radiation. We describe DOS instrumentation design, optical parameters extraction algorithms and the animal handling procedures required to yield representative data from a pre-clinical mouse model of radiation induced erythema.

弥漫性光学光谱治疗急性电离辐射引起的皮肤毒性的定量评价使用小鼠模型

Acute skin toxicities from ionizing radiation (IR) are a common side effect from therapeutic courses of external beam radiation therapy (RT) and ...

医学

A Detailed Protocol for Perspiration Monitoring Using a Novel, Small, Wireless Device

Perspiration monitoring can be utilized for the detection of certain diseases, such as thermoregulation and mental disorders, particularly when the patients are unaware of such disorders or are having difficulty expressing their symptoms. Until now, several devices for perspiration monitoring have been developed; however, such devices tend to have a relatively large exterior, considerable power consumption, and/or less sensitivity.
Recently, we developed a small, wireless device for perspiration monitoring. The device consists of a temperature/relative humidity (T/RH) sensor, battery-driven small data logger, and silica gel as a desiccant in a small cylindrical exterior. The T/RH sensor is placed between the detection windows (through which the water vapor from the skin enters) and the silica gel. The underlying principle of the perspiration monitoring device is based on Fick&#39;s law of diffusion, which means that water vapor flux from the skin to the silica gel (i.e.&#160;transepidermal water loss and perspiration) can be captured by change in humidity at the T/RH sensor. In addition, a baseline subtraction method was adopted to distinguish perspiration and transepidermal water loss.
As shown in the previous report, the developed device can monitor the perspiration at any sites of the body in an easy, wireless manner. However, detailed methods of how to use the device have not been disclosed yet. In this article, therefore, we would like to show the point-by-point tutorials of how to use the device for perspiration monitoring, by showing the sympathetic activity test with the sympathetic skin response monitoring as an example.

Recently, we developed a small wireless device for perspiration monitoring. In this article, we present detailed protocols on how to use the device for perspiration monitoring with an example of the sympathetic activity test.

详细的汗渍监控协议使用一种新的，小的，无线设备

Perspiration monitoring can be utilized for the detection of certain diseases, such as thermoregulation and mental disorders, particularly when the ...

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