博物馆环境监控及相关物联网技术应用需求分析

对博物馆环境实施有效的监控,是预防性保护珍贵文物的有效途径。为广泛发挥物联网在博物馆文物保存环境监控方面的作用,阐述了基于"洁净"概念的博物馆环境及其预防性保护内涵,分析了博物馆环境温湿度、污染气体、光辐射、有害生物四方面监控的特点与需求,介绍了无线传感网络技术在几项重大文物展览活动中的有效应用情况,指出大力加强博物馆环境适宜的监测技术研发,是实现博物馆环境风险预控的关键。     

Real-time Seismic Damage Detection of Concrete Shear Walls Using Artificial Neural Networks

Concrete shear walls are widely employed in buildings as a main resistance system against lateral loads. Early identification of seismic damage to concrete shear walls is vital for deciding post-earthquake occupancy in these structures. In this article, a method based on artificial neural networks for real-time identification of seismic damage to concrete shear walls was proposed. Inter-story drifts and plastic hinge rotation of concrete walls were used as the inputs and outputs of a MLP neural network. Modal Pushover Analysis was employed to prepare well-distributed data sets for training the neural network. The proposed method was applied to a five-story concrete shear wall building. The results from the network were compared with those obtained from Nonlinear Time History Analysis. It was observed that the trained neural network successfully detected damage to concrete shear walls and accurately estimated the severity of seismic-induced damage.     

The Influence of Soil Moisture,Temperature and Oxygen on the Oxic Decay of Organic Archaeological Deposits

The sensitivity of organic‐rich archaeological layers at Bryggen in Bergen, Norway, to changes in soil temperatures, water contents and oxygen concentrations is investigated. This is done by linking measurements of oxic decay at varying temperatures and water contents with on‐site monitoring data using a one‐pool decomposition model. The results show that the model can be used to elucidate the current in situ decay and to evaluate where and when the decay takes place. Future investigations need to include long‐term incubation experiments and decay studies at zero or very low oxygen contents in order to improve the robustness of predictions.     

Multiple Degrees of Freedom Positioning Correction for Hybrid Simulation

This study proposes a high-precision positioning correction method for multiple degree-of-freedom loading units in hybrid simulation. These loading units can impose inaccurate displacements to the specimens due to the elastic deformation at the reaction wall or connections. To compensate for these displacement errors, an online correction method adjusts the displacement command by the difference between the target and achieved displacement. This correction method also accompanies an accurate 6DOF monitoring system to detect the displacement errors. Two examples of hybrid simulation tests are provided to demonstrate the precise displacements attained on the specimens through this control method.     

基于常态条件的石窟寺监测数据预警应用初探

目前国内石窟监测实践在数据采集和存储上已取得较多突破,但在体系化、合理化数据利用上仍存在短板,海量数据受限于劣化机理定量化溯源预测、预防性保护普适性环境参数阈值等研究基础尚不成熟,较难发挥指导、辅助当下保护实践的时效作用。本文依托四川广元千佛崖案例,研究基于常态条件的监测数据实时分级预警体系构建方法,并进行初步应用,探索了一种具有一定推广性并可与保护措施设计、完善、评估以及遗产地管理有机结合的监测预警技术路线。     

Integrating radar and laser-based remote sensing techniques for monitoring structural deformation of archaeological monuments

Ground-Based Synthetic Aperture Radar Interferometry (GBInSAR) and Terrestrial Laser Scanning (TLS) were purposely integrated to obtain 3D interferometric radar point clouds to facilitate the spatial interpretation of displacements affecting archaeological monuments. The paper describes the procedure to implement this integrated approach in the real-world situations of surveillance of archaeological and built heritage. Targeted tests were carried out on the case study of the Domus Tiberiana sited along the northern side of the Palatino Hill in the central archaeological area of Rome, Italy, and displacements of the monument were monitored over almost one year of acquisition. The GBInSAR – TLS integration provided updated information about the condition of the archaeological structures in relation to their history of instability mechanisms, and did not highlighted a general worsening for the stability of the entire monument. Point-wise and prompt detection of displacement anomalies and/or sudden changes in displacement trends proved the suitability of the method to support early warning procedures, also to evaluate effects on the masonry due to human activities.     

基于极限学习机的汉阳陵外藏坑遗址温度预测研究

作为我国首座全封闭式遗址博物馆,汉阳陵外藏坑遗址博物馆已积累超过700万条各类监测数据。然而,受限于海量数据挖掘能力,目前研究中存在监测数据利用率不足和预测模型准确率较低的问题,针对这一问题,引入大数据机器学习领域的极限学习机方法对遗址温度进行系统分析和建模预测。研究结果表明,该方法具有良好的大数据发掘和处理能力,能够有效分析温度的变化规律及特征,并对未来温度变化趋势和细节变化特征实现较为准确的预测。本方法的引入可为遗址预防性保护和管理提供参考。     

不可移动文物保存环境研究——以千手观音造像环境监测与维护方案为例

为充分了解环境因素对千手观音造像受损的影响,准确科学评估千手观音造像损害破坏的机制,2008年8月至2012年12月间对千手观音造像所在的微环境进行了气象和环境空气质量监测,检测了大气颗粒物、雨水、雾水和凝结水成分,同时对脱落的金箔进行破坏机理分析.研究结果表明,千手观音造像所在环境的相对湿度较高、且大气颗粒物污染严重;颗粒物呈酸性,含有较高浓度的硫酸根和硝酸根;造像表面的凝结水中除含有高浓度的硫酸根和硝酸根外,还含有高浓度氯离子,且酸性较高,对千手观音造像存在潜在的破坏作用.本文在此基础上提出了千手观音维护方案,为不可移动文物的保护工作提供参考.     

Wavelet-Based Damage Detection in Reinforced Concrete Structures Subjected to Seismic Excitations

The feasibility of using output-only model-free wavelet-based techniques for damage detection in reinforced concrete structures subjected to seismic loads is explored through the analysis of the results of a full scale shake table test of a reinforced concrete bridge column recently performed at the NEES Large High Performance Outdoor Shake Table. The evaluated approaches are based solely in the analysis of the acceleration time histories recorded in the structure. The viability of using numerical models to validate this type of damage detection methodologies is also evaluated. Wavelet analyses were capable of identifying the rebar fracture episodes and partially identified the frequency shifts in the structure as the inelastic demand increased. It was also found that, depending on the methodology employed, the use of numerical models to validate damage detection techniques can oversimplify the actual problem and/or induce spurious irregularities.     

基于风险管理理论的文化遗产地监测研究

文化遗产地的保护与管理可以视为一种风险管理。对文化遗产面临风险的识别、评估、以及对风险预防与控制,从而实现低成本、高效率的保护与管理文化遗产,体现的是预防性保护的思想和理念。本工作以风险管理理论为指导,通过对文化遗产地风险管理的内容和方法进行研究和分析,提出目前监测工作所面临的一些重要问题,为改进我国文化遗产地监测工作的开展,构建我国文化遗产地监测体系框架以及提高文化遗产地的预防性保护与管理水平提供参考和借鉴。