Robust Fingerprint Construction Based on Multiple Path Loss Model (M-PLM) for Indoor Localization

A robust radio map is essential in implementing a fingerprint-based indoor positioning system(IPS).However,the offline site survey to manually construct the radio map is time-consuming and labour-intensive.Various interpolation techniques have been proposed to infer the virtual fingerprints to reduce the time and effort required for offline site surveys.This paper presents a novel fingerprint interpolator using a multi-path loss model(MPLM)to create the virtual fingerprints from the collected sample data based on different signal paths from different access points(APs).Based on the historical signal data,the poor signal paths are identified using their standard deviations.The proposed method reduces the positioning errors by smoothing out the wireless signal fluctuations and stabilizing the signals for those poor signal paths.By consideringmultipath signal propagations from different APs,the inherent noise from these signal paths can be alleviated.Firstly,locations of the signal data with standard deviations higher than the threshold are identified.The new fingerprints are then generated at these locations based on the proposed M-PLM interpolation function to replace the old fingerprints.The proposed technique interpolates virtual fingerprints based on good signal paths with more stable signals to improve the positioning performance.Experimental results show that the proposed scheme enhances the positioning accuracy by up to 44%compared to the conventional interpolation techniques such as the Inverse DistanceWeighting,Kriging,and single Path LossModel.As a result,we can overcome the site survey problems for IPS by building an accurate radio map with more reliable signals to improve indoor positioning performance.

基于PLS-PATH方法的科技创新对资源利用绩效边际效应测度与分析

探索科技创新对资源利用绩效影响效应,对践行创新发展理念及生态文明建设具有重要启示意义。本文以安徽省为例,采用典型相关分析方法,对资源利用绩效影响因子进行识别;基于STIRPAT模型,采用偏最小二乘回归分析方法,就科技创新等驱动因子对资源利用绩效边际贡献进行测算;运用通径分析方法,就科技创新对资源利用绩效的直接影响效应及通过其他因素产生的间接影响效应进行考察。结果表明:(1)科技创新、经济增长、城镇化、对外开放、市场化程度、环境规制与资源利用综合绩效间呈典型高度正相关,而产业结构与资源利用综合绩效呈典型负相关关系;(2)科技创新对资源利用绩效直接效应低于间接效应。基于研究结果,从高度重视产业结构在资源利用绩效提升中的"木桶"效应等方面,提出了政策建议。

基于PLS-SEM的高速公路施工企业竞争文化建设路径研究

为充分挖掘高速公路施工企业竞争文化要素间的作用关系,提升高速公路施工企业竞争意识,推动交通强国战略目标实现,本文对高速公路施工企业竞争文化建设路径进行探究。利用词频-逆向文件频率(TF-IDF)算法对291家施工企业的竞争文化文本表现特征进行提取,构建个人要求、晋升激励、质量成本管理、部门管理理念、合作与竞争观念、社会责任与使命6个影响因素的高速公路施工企业竞争文化作用关系概念模型。通过偏最小二乘法结构方程模型(PLS-SEM)分析各要素间的作用关系。最后,基于竞争文化要素间的路径系数,构建激励型路径、引导型路径和反馈型路径共3种高速公路施工企业竞争文化建设路径。

Channel Measurement and Path Loss Modeling from 220 GHz to 330 GHz for 6G Wireless Communications

Terahertz(THz)communication has been envisioned as a key enabling technology for sixthgeneration(6G).In this paper,we present an extensive THz channel measurement campaign for 6G wireless communications from 220 GHz to 330 GHz.Furthermore,the path loss is analyzed and modeled by using two single-frequency path loss models and a multiplefrequencies path loss model.It is found that at most frequency points,the measured path loss is larger than that in the free space.But at around 310 GHz,the propagation attenuation is relatively weaker compared to that in the free space.Also,the frequency dependence of path loss is observed and the frequency exponent of the multiple-frequencies path loss model is 2.1.Moreover,the cellular performance of THz communication systems is investigated by using the obtained path loss model.Simulation results indicate that the current inter-site distance(ISD)for the indoor scenario is too small for THz communications.Furthermore,the tremendous capacity gain can be obtained by using THz bands compared to using microwave bands and millimeter wave bands.Generally,this work can give an insight into the design and optimization of THz communication systems for 6G.

Investigating path loss characteristics of UWB signals in vacancy indoor environment based on time-domain technique

The path loss analysis model based on 5 rays in vacancy indoor environment is proposed. The relationship between multipath overlapping and the path loss is analyzed mathematically. Time-domain technique is introduced to compute reflection coefficient in a very short time interval. A 5 rays path loss calculation method, which is satisfactory accurate, is developed. 5 typical environments are involved to analyze and generalize the common path loss characteristics in vacancy indoor environment. The simulation result shows that the path loss can be characterized as 3 zones with different path loss exponent as distance between transmitter and receiver increasing.

Intelligent Reflecting Surfaces Enabled Cognitive Internet of Things Based on Practical Pathloss Model

In this paper,we aim to unlock the potential of intelligent reflecting surfaces(IRSs)in cognitive internet of things(loT).Considering that the secondary IoT devices send messages to the secondary access point(SAP)by sharing the spectrum with the primary network,the interference is introduced by the IoT devices to the primary access point(PAP)which profits from the IoT devices by pricing the interference power charged by them.A practical path loss model is adopted such that the IRSs deployed between the IoT devices and SAP serve as diffuse scatterers,but each reflected signal can be aligned with its own desired direction.Moreover,two transmission policies of the secondary network are investigated without/with a successive interference cancellation(SIC)technique.The signal-to-interference plus noise ratio(SINR)balancing is considered to overcome the nearfar effect of the IoT devices so as to allocate the resource fairly among them.We propose a Stackelberg game strategy to characterize the interaction between primary and secondary networks.For the proposed game,the Stackelberg equilibrium is analytically derived to optimally obtain the closed-form solution of the power allocation and interference pricing.Numerical results are demonstrated to validate the performance of the theoretical derivations.

Path loss modelling and comparison based on the radio propagation measurement at 3.5GHz

Wideband IMT-Advanced mobile communication systems tend to operate in the high frequency bands due to a relatively large capacity available. Thus, Measurement and modelling methods of radio propaga- tion eharaeteristics are proposed for the field test of Chinese 4th generation （4G） trial system. The mea- surement system is established for 3.5GHz based on the sophistieated measurement instruments and the virtual instrument teehnology. The characteristic parameters of radio propagation sueh as path loss （PL） exponent and shadow fading standard deviation are extracted from measurement data, which result in the path loss model finally. The comparisons with other existing international models results validate our mea- surement in terms of path loss model. Based on the analysis of the existing extension model assumed for the microwave frequency at 3.5GHz, we find that the Stanford University Interim （SUI） model fits very well with the measurement result in the hotspot scenario, while the COST 231 model is closer to the mea- surement result in the suburban scenario. This result provides a measurement-based channel referenee for the development of the future IMT-Advanced systems in China.

A 4H-SiC trench IGBT with controllable hole-extracting path for low loss

A novel 4H-Si C trench insulated gate bipolar transistor(IGBT)with a controllable hole-extracting(CHE)path is proposed and investigated in this paper.The CHE path is controlled by metal semiconductor gate(MES gate)and metal oxide semiconductor gate(MOS gate)in the p-shield region.The grounded p-shield region can significantly suppress the high electric field around gate oxide in Si C devices,but it weakens the conductivity modulation in the Si C trench IGBT by rapidly sweeping out holes.This effect can be eliminated by introducing the CHE path.The CHE path is pinched off by the high gate bias voltage at on-state to maintain high conductivity modulation and obtain a comparatively low on-state voltage(VON).During the turn-off transient,the CHE path is formed,which contributes to a decreased turn-off loss(EOFF).Based on numerical simulation,the EOFFof the proposed IGBT is reduced by 89%compared with the conventional IGBT at the same VONand the VONof the proposed IGBT is reduced by 50%compared to the grounded p-shield IGBT at the same EOFF.In addition,the average power reduction for the proposed device can be 51.0%to 81.7%and 58.2%to 72.1%with its counterparts at a wide frequency range of 500 Hz to 10 k Hz,revealing a great improvement of frequency characteristics.

Maximum Inner Product Method for Extracting the Path-Loss Parameters in Primary Transformer Substations

In order to deploy short-range wireless communication devices in the primary transformer substation, a Maximum Inner Product(MIP) Method is proposed to extract the path-loss parameters in 110 kV and 220 kV primary transformer substations. The maximum inner product of the testing data is calculated to find out the loss index n and the standard deviation σ, and then the pathloss models can be set up. By comparing the MIP with Minimum Mean Square estimation(MMSE) and Cumulative Sum(CUSUM), MIP can match the measured values best. In order to apply the MIP path-loss model, under the initial signal to noise ratio(SNR) at 5 dB and 10 dB, a ZigBee simulation system is constructed to validate the situation that bit error rate(BER) varies with distance. And the ZigBee devices with 5 units are tested in a 220 kV primary transformer substation. The result of the test proves that the path-loss model is accurate.

Statistical Model of Path Loss for Railway 5G Marshalling Yard Scenario

The railway mobile communication system is undergoing a smooth transition from the Global System for Mobile Communications-Railway(GSM-R)to the Railway 5G.In this paper,an empirical path loss model based on a large amount of measured data is established to predict the path loss in the Railway 5G marshalling yard scenario.According to the different characteristics of base station directional antennas,the antenna gain is verified.Then we propose the position of the breakpoint in the antenna propagation area,and based on the breakpoint segmentation,a large-scale statistical model for marshalling yards is established.

Path Loss Modeling: A Machine Learning Based Approach Using Support Vector Regression and Radial Basis Function Models

Path loss prediction models are vital for accurate signal propagation in wireless channels. Empirical and deterministic models used in path loss predictions have not produced optimal results. In this paper, we introduced machine learning algorithms to path loss predictions because it offers a flexible network architecture and extensive data can be used. We introduced support vector regression (SVR) and radial basis function (RBF) models to path loss predictions in the investigated environments. The SVR model was able to process several input parameters without introducing complexity to the network architecture. The RBF on its part provides a good function approximation. Hyperparameter tuning of the machine learning models was carried out in order to achieve optimal results. The performances of the SVR and RBF models were compared and result validated using the root-mean squared error (RMSE). The two machine learning algorithms were also compared with the Cost-231, SUI, Egli, Freespace, Cost-231 W-I models. The analytical models overpredicted path loss. Overall, the machine learning models predicted path loss with greater accuracy than the empirical models. The SVR model performed best across all the indices with RMSE values of 1.378 dB, 1.4523 dB, 2.1568 dB in rural, suburban and urban settings respectively and should therefore be adopted for signal propagation in the investigated environments and beyond.

Modified Ceiling Bounce Model for Computing Path Loss and Delay Spread in Indoor Optical Wireless Systems

This paper proposes modifications to the tradional Ceiling Bounce Model and uses it to characterize diffuse indoor optical wireless channel by analyzing the effect of transceiver position on signal propagation properties. The modified approach uses a combination of the tradional ceiling bounce method and a statistical approach. The effects of different transmitter-receiver separations and height of the ceiling on path loss and delay spread are studied in detail.

Propagation Path Loss Models at 28 GHz Using K-Nearest Neighbor Algorithm

In this paper,we develop and apply K-Nearest Neighbor algorithm to propagation pathloss regression.The path loss models present the dependency of attenuation value on distance using machine learning algorithms based on the experimental data.The algorithm is performed by choosing k nearest points and training dataset to find the optimal k value.The proposed method is applied to impove and adjust pathloss model at 28 GHz in Keangnam area,Hanoi,Vietnam.The experiments in both line-of-sight and non-line-of-sight scenarios used many combinations of transmit and receive antennas at different transmit antenna heights and random locations of receive antenna have been carried out using Wireless Insite Software.The results have been compared with 3GPP and NYU Wireless Path Loss Models in order to verify the performance of the proposed approach.

Propagation Modeling and Characteristic Analysis of Terahertz Waves via High Altitude Platforms

Satellite-to-ground terahertz communication is limited by the power of signal source and antenna gain level,and has large path loss,which is difficult to implement.In this paper,a feasible scheme of satellite-to-ground terahertz communication using High Altitude Platforms(HAPs)as relay is presented,and the path loss on terahertz communication links is modeled and analyzed.Combined with the path loss model,the transmission loss along HAP-to-ground paths under different seasons and complex weather environment in Ali,Xizang,China is calculated.The results show that the transmission characteristics of terahertz waves in winter and summer are significantly different,mainly reflected in the number and bandwidth of usable atmospheric windows.Furthermore,the additional attenuation caused by the typical sand dust and ice cloud environment on terahertz band can reach 6.1 dB and 1.9 dB at the maximum respectively.With the aid of high gain antenna,the usable communication frequencies of the HAP-to-ground links in winter are significantly more than those in summer.When the transmitting and receiving antenna gain is 40 dBi respectively,the usable communication frequency can reach 1.35 THz in winter,while it is limited to less than 1 THz in summer,up to 0.493 THz.

Fine-grained grid computing model for Wi-Fi indoor localization in complex environments

The fingerprinting-based approach using the wireless local area network(WLAN)is widely used for indoor localization.However,the construction of the fingerprint database is quite time-consuming.Especially when the position of the access point(AP)or wall changes,updating the fingerprint database in real-time is difficult.An appropriate indoor localization approach,which has a low implementation cost,excellent real-time performance,and high localization accuracy and fully considers complex indoor environment factors,is preferred in location-based services(LBSs)applications.In this paper,we proposed a fine-grained grid computing(FGGC)model to achieve decimeter-level localization accuracy.Reference points(RPs)are generated in the grid by the FGGC model.Then,the received signal strength(RSS)values at each RP are calculated with the attenuation factors,such as the frequency band,three-dimensional propagation distance,and walls in complex environments.As a result,the fingerprint database can be established automatically without manual measurement,and the efficiency and cost that the FGGC model takes for the fingerprint database are superior to previous methods.The proposed indoor localization approach,which estimates the position step by step from the approximate grid location to the fine-grained location,can achieve higher real-time performance and localization accuracy simultaneously.The mean error of the proposed model is 0.36 m,far lower than that of previous approaches.Thus,the proposed model is feasible to improve the efficiency and accuracy of Wi-Fi indoor localization.It also shows high-accuracy performance with a fast running speed even under a large-size grid.The results indicate that the proposed method can also be suitable for precise marketing,indoor navigation,and emergency rescue.

基于熵值法修正PLS权重的学术期刊综合评价

[目的/意义]期刊评价指标间多重共线性与指标权重不确定性是学术期刊评价面临的两大难题。基于此,提出一种新的复合评价模型。[方法/过程]首先以图情类期刊为例构建PLS路径模型得到各指标外部权重,其次通过熵值法的差异系数对PLS路径模型的外部权重进行修正,最终确定各指标的权重、构造加权规范矩阵,最后用加权TOPSIS法比较样本期刊与最优解的相对贴近度并进行排序分析。[结果/结论]通过实证研究表明,该方法有效消除了指标间的多重共线性,合理为指标赋权,且对期刊的评价结果是有效的、合理的。

PLS路径模型在省域高校科技活动综合评价中的实证研究

对高校科技活动进行综合评价是科研管理的重要课题之一。基于PLS路径模型,建立各省高校科技活动综合评价指数,运用2007年的数据,对31个省的高校科技活动进行了综合评价。结果显示:"知识产权产出"和"投入"是对省域高校科技活动综合水平影响最大的两个因素,西部大多数省份高校的科技活动水平落后于中东部。

我国部属高校科技活动综合评价——基于PLS路径模型的实证研究

本文运用PLS路径模型这一多指标综合评价方法综合评价高校科技活动.以我国60所部属高校科技活动为例,设计了相应的综合评价指标体系,采用PLS模型方法构建了我国部属高校科技活动综合评价模型.运用2007年的数据对我国部属高校的科技活动进行综合评价,并对所测算的综合评价指数进行了聚类分析.研究结果表明,科研活动和社会效益等指标因素对我国部属高校科技活动综合能力影响最大.各高校应根据评价综合得分和排名,辨识自身的相对优势和不足,采取措施提高科技活动综合能力.

视频检索相关性判断的影响因素:基于PLS路径分析的实证研究

相关性判断是用户视频检索与查寻中的关键一环,调查视频检索情境下相关性判断的影响因素,对视频检索系统的设计与开发具有重要意义。以现有理论为基础,结合视频检索的特性,本文构建了影响视频检索相关性判断的因素模型,利用实验与问卷相结合的方式收集数据,并采用PLS路径分析方法进行了数据分析和模型检验。结果显示,测量模型满足信度和效度检验;结构模型表明,主题性、范围和权威性依次是影响视频检索中相关性判断的显著因素,而可理解性、可获取性和视频特性均未发现具有统计学上的显著影响。同时,范围对主题性也具有显著影响,并通过主题性对相关性产生间接影响。此外,调节变量分析发现,性别、信息搜索能力和主题熟悉度会显著调节部分影响因素对相关性的影响。研究表明,相关性判断影响因素在不同情境以及不同类型信息之间具有一定的稳定性,同时也具有一定的差异性。本研究建议,除了主题性之外,视频信息检索系统的设计应该考虑到其他因素的影响,从而帮助用户快速有效地查找和获取所需的视频。