Two-stage fuzzy-stochastic robust programming: a hybrid model for regional air quality management

In this study, a hybrid two-stage fuzzy-stochastic robust programming (TFSRP) model is developed and applied to the planning of an air-quality management system. As an extension of existing fuzzy-robust programming and two-stage stochastic programming methods, the TFSRP can explicitly address complexities and uncertainties of the study system without unrealistic simplifications. Uncertain parameters can be expressed as probability density and/or fuzzy membership functions, such that robustness of the optimization efforts can be enhanced. Moreover, economic penalties as corrective measures against any infeasibilities arising from the uncertainties are taken into account. This method can, thus, provide a linkage to predefined policies determined by authorities that have to be respected when a modeling effort is undertaken. In its solution algorithm, the fuzzy decision space can be delimited through specification of the uncertainties using dimensional enlargement of the original fuzzy constraints. The developed model is applied to a case study of regional air quality management. The results indicate that reasonable solutions have been obtained. The solutions can be used for further generating pollution-mitigation alternatives with minimized system costs and for providing a more solid support for sound environmental decisions.     

Particle generation by ultraviolet-laser ablation during surface decontamination

A novel photonic decontamination method was developed for removal of pollutants from material surfaces. Such a method relies on the ability of a high-energy laser beam to ablate materials from a contaminated surface layer, thus producing airborne particles. In this paper, the authors presented the results obtained using a scanning mobility particle sizer (SMPS) system and an aerosol particle sizer (APS). Particles generated by laser ablation from the surfaces of cement, chromium-embedded cement, and alumina were experimentally investigated. Broad particle distributions from nanometer to micrometer in size were measured. For stainless steel, virtually no particle > 500 nm in aerodynamic size was detected. The generated particle number concentrations of all three of the materials were increased as the 266-nm laser fluence (millijoules per square centimeter) increased. Among the three materials tested, cement was found to be the most favorable for particle removal, alumina next, and stainless steel the least. Chromium (dropped in cement) showed almost no effects on particle production. For all of the materials tested except for stainless steel, bimodal size distributions were observed; a smaller mode peaked at approximately 50-70 nm was detected by SMPS and a larger mode (peaked at approximately 0.70-0.85 microm) by APS. Based on transmission electron microscopy observations, the authors concluded that particles in the range of 50-70 nm were aggregates of primary particles, and those of size larger than a few hundred nanometers were produced by different mechanisms, for example, massive object ejection from the material surfaces.     

环境管理日常监督检查的规范化

介绍了洛阳分公司在环境管理中实施的一套有效的日常监督检查机制,及时发现和纠正偏差,提高了环境管理体系的运行效率。     

Abusive supervision and work behaviors: The mediating role of LMX

We investigated the mediating role of the leader–member exchange (LMX) in the association of abusive supervision and employee work behaviors (task performance and organizational citizenship behaviors toward the organization and individuals). Using data collected from 366 supervisor–subordinate dyads, we found that LMX fully mediated the negative effects of abusive supervision on all three work behaviors. In addition, we conducted a supplementary study on the basis of the data collected from 54 supervisor–subordinate dyads from a garment company, and we found that LMX mediated the relationship between abusive supervision and employee objective future performance with interactional justice controlled. Copyright © 2011 John Wiley & Sons, Ltd.     

The many benefits of employee well‐being in organizational research

We undertake three objectives in this Incubator. We begin with a discussion of how well‐being has been considered in organizational research. Second, we provide an overview of the relationship between employee well‐being and such workplace outcomes as job performance, employee retention, and cardiovascular health. Third, we introduce exciting research directions. Copyright © 2012 John Wiley & Sons, Ltd.     

Experimental study on non-destructive testing of rock bolts based on pseudo-random signal

The quality of rock bolt anchoring is closely related to the stability and safety of underground engineering and slope protection. In this paper, non-destructive testing of rock bolts is proposed based on pseudo-random signal, owing to the deficiencies of the conventional detecting method of stress wave reflection. The characteristics of pseudo-random signal for non-destructive testing of rock bolts are introduced. And the rock bolts are tested in the experiment, the time of reflection wave is identified and the length of rock bolts is calculated through cross correlation analysis between the extracted wavelet signal and the test signal. It is proved that the testing results of non-destructive testing methods based on pseudo-random signal are of low deviation. The experiment has shown that non-destructive testing of rock bolts based on pseudo-random signal is feasible with high precision.     

Exploring the perceived influence of safety management practices on project performance in the construction industry

Although safety management is known to be vital to construction projects, very few studies have solicited views from construction practitioners about their perceptions of which safety management practices (SMPs) are important to construction projects and related to project performance. An empirical study was undertaken in Hong Kong in order to shed more light on this topic. In the study, the importance levels of 15 popular SMPs and five project performance criteria were rated by 232 respondents. An exploratory factor analysis was conducted, and three SMP categories - information, process, and committees - were extracted. Of these three categories, safety management process was perceived by the construction practitioners as being the most important, followed by safety management information and committees. Moreover, the effect of the three SMP categories on a composite project performance variable was tested using hierarchical regression analysis. Results indicate that the “information” and “committees” categories were associated with project performance positively and significantly. One of the major conclusions of the study is that the construction industry has paid relatively less attention to safety management committees, which were empirically analyzed as having a strong perceived impact on project performance. In order to improve project performance, construction companies should promote the criticality of safety management committees.     

Quantitative indicator of homeostatic risk perception in car following

Driving behavior is largely affected by the risk perception of drivers. On the basis of risk homeostasis theory, we regard that drivers may adjust car movement according to the perceived risks fluctuating around a target level. However, the manner by which risk perception is quantified remains unclear. We propose assumptions on the quantitative indicators of risk perception and identify a suitable quantitative indicator of risk perception in car-following process. Three risk indicators are discussed, i.e. time-to-collision (TTC), time headway (TH), and safety margin (SM). Using homeostatic features as bases, we found that SM more suitably quantifies homeostatic risk perception than TTC or TH does. Data collected from video drive recorders installed in taxis operating in Beijing are used to analyze the target risk level of SM (desired SM, or DSM) of professional drivers during the car-following process. The data collected by Ahn et al. (2004) to verify Newell’s model are converted into DSM data to further analyze the target risk level of general drivers. The DSM histogram of professional drivers shows that the standard deviation of the DSM value is 0.115, with a mean value of 0.862 and a total distribution close to the normal distribution. For a general driver, the mean value of DSM is 0.896, which is higher than that of professional drivers. This research may shed lights on the understanding of driving behavior.     

一种验证可变速电梯变速功能安全性的检验方法

在分析可变速电梯原理的基础上,研究了可变速电梯变速功能安全性对其正常运行产生的影响,提出了验证可变速电梯变速功能安全性的检验内容与检验方法。试验采用了普通累积法作为测量数据的处理方法,完成了对称重系统的误差评定。试验证明,该检验方法可以有效地反映可变速电梯变速功能的安全状态。     

防护鞋靴有害物质限量值研究

本文对防护鞋靴有害物质限量值研究进行了阐述。参考国内外标准,设定防护鞋靴有害物质限制项目和限量值。在检测分析我国具有市场代表性的16个防护鞋靴产品中有害物质含量数据基础上,判断设定限制项目及限量值的可行性。检测结果表明我国防护鞋靴生产技术水平基本能够达到限量要求,设定的限量值可以作为制定国家标准的参考依据。