基于降阶核范数的PMU数据快速恢复方法

相量量测装置(phasor measurement unit,PMU)数据由于受通信问题、网络攻击与电磁干扰等因素影响可能会出现数据缺失、虚假数据与噪声等量测污染。现有PMU数据恢复方法无法同时满足高精度、快速与适应多场景数据恢复的要求,可能影响电力系统的安全稳定运行。提出一种基于降阶核范数的数据恢复方法,利用数据的高维低秩性在每次算法迭代中进行低阶奇异值分解,同时将数据主成分与量测污染进行特征分离,能以较高精度对多种数据污染场景与系统不同状态下的量测数据进行恢复。为进一步减少大规模电力量测数据恢复的时间消耗并提高算法的迭代效率,提出自适应惩罚因子与并行分布式交替乘子算法数据恢复框架,能有效将数据恢复时间控制在秒级,可为基于PMU数据的各电力系统应用提供有效保障。

Impacts of Agricultural Non-point Pollution on Water-source Area in Songhua Dam

[Objective] The aim was to research impacts of agricultural non-point pol- lution on water-source region in Songhua Dam, laying foundation for control of water pollution and scientific protection of water-source region. [Method] Water in Muyang River, lengshui River and Zizania aquatica region were sampled to measure content of pollutants in water and conclude relation between water contamination and agri- cultural non-point pollution to find the major cause of pollution. [Result] Organic pollu- tant in Muyang River was higher; N and P contents in Lengshui River were higher; the measured indices in Zizania aquatica region excessively exceeded related stan- dard. [Conclusion] The chemical fertilizers and pesticides are the toxic materials lead- ing to water contamination and constitute a major cause of pollution in Songhua Dam water-source region. Agricultural non-point pollution should be controlled in a scientific way.

Response of soil fungal community to long-term chromium contamination

To further study the fungal community in heavy metal contaminated ecosystems,soil samples were collected from an abandoned chromium(Cr)factory,and fungal community was analyzed by Illumina sequencing of Internal Transcribed Spacer(ITS)amplicons.The results showed that Cr contamination changed the composition and structure of soil fungal community,but didn’t change the diversity.Fungus showed various responses to Cr contamination.LEfSe analysis revealed that the biomarker changed a lot in the Cr-contaminated samples in comparison with that in the control samples.The changes in fungal community may be caused by the direct toxic effects on fungi by high concentration of Cr and the significant change in soil properties resulting from Cr contamination.Among all the Cr fractions,organic matter-bound Cr and exchangeable Cr showed significant effects on the fungal community and organic matter also showed a significant effect on soil fungal community.

Air Pollution Concentration Approach to Potential Area Selection of the Air Quality Monitoring Station in Nakhon Ratchasima Municipality, Thailand

The purpose of the study is to generate traffic air information system） to determine a proper zone of AQMS （air analyzed were carbon monoxide （CO）, and nitrogen oxides （NOx） pollution map using mathematical model and GIS （geographic quality monitoring station） in municipality area. The pollutants which can be harmful to people living in the area. The three steps of mapping process were performed under the GIS environment using the existing vehicle emission rates and pollutant dispersion model. First, traffic volume, road network, and the emission rates of road segments varying with types of vehicle were collected from existing data. Second, the pollutant concentrations were calculated by use of CALINE4, a tool with Gaussian dispersion model. The model parameters include emission rate, wind directions and speeds, ambient temperature and observed pollutant concentration, and atmospheric stability during all seasons from the January 1, 2010 to May 31,2011 with regardless the rainy season. This resulted in concentrations at many receptor points along links of the road network. Third, distributions of pollution concentrations were generated by means of the spatial interpolation of those from receptors. The results of pollution raster-based maps are used for determining frequency of violence and combined pollution map. The resulting frequency of violence and intensity concentration will be further integrated to determine a potential area of AQMS. Finally, achieving pollution potential area of AQMS can be located as helpful basic data for efficient traffic and transportation planning.

Measurement factors of pollutants inside vehicle

The air quality inside vehicle is concerned widely in the world. The pollution inside vehicle is special serious in China. State Environmental Protection Administration of China is formulating the standard of air quality inside vehicle. However the measurement relates to many factors. Because of the small space, temperature easy changed, various ventilation modes, being close to pollution source of engine exhaust, there are differences between in-vehicle and indoor measurement. The influence of measuring factors was investigated. Those factors include temperature, preconditioning time, ventilation modes, engine state, and sampling fashion. The measuring mode and relating factors were discussed. The suggestion was offered.

Image-based Water Level Measurement Method under Stained Ruler

This paper propoes the water level measuring method based on the image, while the ruler used to indicate the water level is stained. The contamination of the ruler weakens or eliminates many features which are required for the image processing. However, the feature of the color difference between the ruler and the water surface are firmer on the environmental change compare to the other features. As the color differeaces are embossed, only the region of the ruler is limited to eliminate the noise, and the average image is produced by using several continuous frames. A histogram is then produced on the height axis of the produced intensity average image. Local peaks and local valleys are detected, and the section between the peak and valley which have the greatest change is looked for. The valley point at this very moment is used to detect the water level. The detected water level is then converted to the actual water level by using the mapping table. The proposed method is compared to the ultrasonic based method to evaluate its accuracy and efficiency on the various contaminated environments.

Traffic Noise Pollution： Spectra Characteristics and Windows Sound Insulation in Laboratory and Field Measurements

The traffic spectra influence on indoor noise through windows is evaluated with laboratory and field measurements. Different traffic noise spectra were registered and reproduced, simulating the outdoor traffic conditions through different windows. Spectrum adaptation terms for the recorded spectra were different from the ones obtained from the Standards, showing that Normative gives a safe evaluation of the Weighted Sound Insulation Index. In field measurements, the level abatements calculated from the Facade Acoustic Insulation Index corrected with the adaptation terms shows that the ones from the Standard do not give a good approximation, while if the level abatements is calculated using the adaptation terms from the registered spectra, a more reliable approximation is achieved. Furthermore, comparing the level abatements for two windows having both Rw equal to 41 dB, very different values were obtained at different frequencies; therefore to characterize acoustic performances of windows, sound insulation curves are also needed. The correlation between the mean difference between adaptation terms calculated from the standard and the one between abatements obtained with pink noise and the ones obtained with the registered spectra is good, but different for road traffic and trains. In both, the difference diminishes when the difference between the abatements increases.

Rapid identification of single constant contaminant source by considering characteristics of real sensors

For the release of hazardous contaminant indoors, source identification is critical for developing effective response measures. A method which can quickly and accurately identify the position, emission rate, and release time of a single constant contaminant source by using real sensors was presented. The method was numerically demonstrated and validated by a case study of contaminant release in a three-dimensional office. The effects of the measurement errors and total sampling period of sensor on the performance of source identification were thoroughly studied. The results indicate that the adverse effects of the measurement errors can be mitigated by extending the total sampling period. For reaching a desirable accuracy of source identification, the total sampling period should exceed a certain threshold, which can be determined by repeatedly running the identification method tmtil the results tend to be stable. The method presented can contribute to develop an onsite source identification system for protecting occupants from indoor releases.

Investigation of Subsurface Contamination due to Chromium from Tannery Effluent in Kasur District of Pakistan

The present study is conducted in the scenario of the tannery waste hazards in Kasur district of Pakistan where the tannery industry is considered as major cause of groundwater quality deterioration, Area focused in this research constitutes the surroundings of the effluent carrying drains near tannery units. This study includes soil explorations, groundwater monitoring and wastewater analysis in the research area so as to find out the contamination extent of chromium in subsurface. Initial groundwater monitoring exhibited chromium concentrations as high as 90 mg/L in the tannery area. Even groundwater sampling from monitoring wells installed in the adjacent areas of effluent carrying drains, showed concentrations up to 10.4 mg/L. Wastewater analysis of all the drains in the research area has evidenced potential risk of contaminant seepage into soil and groundwater as level of chromium in wastewater samples has reported to be immensely high and varies from 68 mg/L to 2,152 mg/L. However the 30 soil samples collected from two soil bores did not show any significant results as the maximum values obtained for hexavalent chromium for leaching and retained in soil are 0.02 mg/L and 8.1 mg/kg, respectively. These low concentrations of soil samples suggest that the soil contamination may not be a main environmental issue in the areas adjacent to the effluent carrying drains, The research concludes as possibility of direct interference of the tannery wastewater with groundwater through damaged structures and sewers.

Using Support Vector Regression to Analyze Urban Atmosphere Pollution with Optical Remote Sensing Data

The concentration of absorbable particulate matter less than 10 μm termed as PM10 is the most important urban air pollution index for air quality monitoring. This paper presents a space based PM10 monitoring algorithm based on QUAC （QUick atmosphere correction） for optical remote sensing data and SVR （support vector regression）. PM 10 concentration measurements from nine ground based stations in Hangzhou, China and the MODIS （moderate-resolution imaging spectroradiometer） images were analyzed. Experimental result indicates that the correlation between CD （correction differences） with actual measured data is better than correlation between AOD （aerosol optical depth） with measured data. In addition, the fitting performance of the SVR model established with CD and measured data is better than traditional regression models.

Comparisons of measured nitrous acid(HONO) concentrations in a pollution period at urban and suburban Beijing, in autumn of 2014

To study the HONO formation mechanisms during a pollution period, a continuous measurement was performed in both urban and suburban aeras of Beijing. During this period, the PM2.5 concentrations increased to 201 and 137 ?g/m3 in urban and suburban areas, respectively. The concentrations of HONO, CO, SO2, O3, NO, NO2, NOx were 1.45 ppbv, 0.61 ppmv, 8.7 ppbv, 4.3 ppbv, 44.4 ppbv, 37.4 ppbv, 79.4 ppbv and 0.72 ppbv, 1.00 ppmv, 1.2 ppbv, 7.9 ppbv, 3.7 ppbv, 8.2 ppbv, 11.9 ppbv, in urban and suburban areas, respectively. To compare possible pathways of HONO formation in both sites, the contributions of direct emissions, heterogeneous formations, and homogeneous productions were studied. HONO/NO2 ratios in the two sites indicated that heterogeneous reactions of NO2 were more efficient in suburban areas. And in both urban and suburban areas, the increase of PM2.5 concentrations and RH would promote the conversion efficiency in RH that ranged from 0% to 85%. However, when RH was above 85%, the HONO formation slowed down. Moreover, the study of direct emissions and homogeneous reactions showed that they contributed to a majority of HONO increase in urban areas than the 20% contributions in suburban areas. It implied that the high NOx concentrations and NO concentrations in urban areas or in pollution periods would make direct emissions and homogeneous reactions become dominant in HONO formations.

On the nature of X-ray “unobscured” Seyfert 2 galaxies

We present a systematic study to reveal the effect of host galaxy contamination to the identification of X-ray "unobscured" Seyfert 2 galaxies.We compiled a sample of 14 X-ray "unobscured" Seyfert 2 galaxies and 29 X-ray obscured Seyfert 2s,with infrared [Ne II] and [O IV] emission line flux measurements.In this work we classify Seyfert 2s as "unobscured" or obscured in X-ray simply based on X-ray spectral fitting.We find that our X-ay "unobscured" Seyfert 2s have statistically higher [Ne II]/[O IV] line ratios,compared with obscured ones.Since the [Ne II]/[O IV] line ratio reflects the relative strength of star formation activity comparing with the SMBH accretion,the observed differences in [Ne II]/[O IV] line ratios clearly indicate relatively stronger X-ray contamination from star formation in the host galaxies in X-ray "unobscured" Seyfert 2s.Therefore we could attribute the X-ray "unobscured" appearance to host galaxy contamination for most(if not all) of our X-ray "unobscured" Seyfert 2s.Further analysis indicates that "unobscured" Seyfert 2s have intrinsically lower AGN luminosity but similar star formation rates,compared with obscured ones.This is also consistent with previous studies showing most X-ray "unobscured" Seyfert 2s are at lower luminosities,and relatively stronger contaminations from the host galaxies are thus expected.Finally we develop a screening criterion to distinguish potential pure Seyfert 2s from X-ray "unobscured" appearances which could be caused by strong host galaxy contamination.

Terahertz-dependent PM2.5 monitoring and grading in the atmosphere

Rapid industrialization and economic development have led to serious pollution in the form of fine particulate matter(PM2.5,particulate matter with a diameter of less than 2.5 μm). In China, PM2.5 has been one of the most debated topics in councils of government and issues of public concern. Terahertz(THz) radiation was employed to measure the PM2.5 in the atmosphere from September 2014 to April 2015 in Beijing. Comparison of the PM2.5 level from the website with THz absorbance revealed a significant phenomenon: THz radiation can be used to monitor PM2.5 in the atmosphere. During Asia-Pacific Economic Cooperation(APEC) 2014, "APEC Blue" was also recorded in a THz system. The relationship between absorbance and PM2.5 demonstrates that THz radiation is an effective selection for air pollution grading. Based on the absorbance spectra, the elemental compositions were studied by two-dimensional correlation spectroscopy(2 DCOS) in conjunction with X-ray fluorescence.Several single absorption peaks were revealed and caused by sulphate from coal combustion, vehicle exhaust emissions and secondary reactions. Furthermore, mathematical algorithms, such as the BPANN and SVM, can process the THz absorbance data and greatly improve the precision of the estimation of PM2.5 mass. Our results suggest that THz spectroscopy can not only reveal the component information for pollution source determination, but quantitatively monitor the PM2.5 content for pollution level evaluation. Therefore, the use of THz radiation is a new method for future air pollution monitoring and grading systems.

Temperature effect on the sensitivity of the copepod Eucyclops serrulatus （Crustacea, Copepoda, Cyclopoida） to agricultural pollutants in the hyporheic zone

The sensitivity of freshwater invertebrates to agricultural pollutants is supposed to increase with rising temperature due to global warming. The aim of this study was to measure the effect of temperature on the lethal toxicity of ammonia-N, the herbicide Imazamox and the mixture of the two chemicals, in the adults and the juveniles of a population of the copepod Eucyc- lops serrulatus. This is a widely distributed species found in surface waters, in transitional habitats between surface water and groundwater, and in genuine groundwater environments. We tested the sensitivity by short-term bioassays （96 h） at 15℃ and 18℃, respectively. Our results highlighted the following： （1） increasing temperature affected the sensitivity of the adults to am- monia-N and of the juveniles to the mixture, all of which were more sensitive to its detrimental effects at 18~C; （2） the juvenile stages were more sensitive than the adults to all toxicants, and （3） for all combinations of chemicals and temperatures, the effects were synergistic and approximately one order of magnitude greater than those expected according to a concentration addition model when comparing the LC50 for each chemical in the mixture with the LC50s of chemicals individually assayed. Overall, in a context of global change, ammonia-N and mixtures of agricultural pollutants may affect the survival rate of species that spend a part or the whole life-cycle in the hyporheic habitat, with detrimental effects to biodiversity and ecosystem services provided by the hyporheic biota [Current Zoology 61 （4）： 629~540, 2015].

Aerosol properties over an urban site in central East China derived from ground sun-photometer measurements

Sun-photometer measurements at Hefei,an urban site located in central East China,were examined to investigate the variations of aerosol loading and optical properties.It is found that aerosol optical thickness(AOT)keeps higher in winter/spring and gets relatively lower in summer/autumn.The large AOT in winter is caused by anthropogenic sulfate/nitrate aerosols,while in spring dust particles elevate the background aerosol loading and the excessive fine-mode particles eventually lead to severe pollution.There is a dramatic decline of AOT during summer,with monthly averaged AOT reaching the maximum in June and soon the minimum in August.Meanwhile,aerosol size decreases consistently and single scattering albedo(SSA)reaches its minimum in July.During summertime large-sized particles play a key role to change the air from clean to mild-pollution situation,while the presence of massive small-sized particles makes the air being even more polluted.These complicated summer patterns are possibly related to the three key processes that are active in the high temperature/humidity environment concentrating on sulfate/nitrate aerosols,i.e.,gas-to-particle transformation,hygroscopic growth,and wet scavenging.Regardless of season,the increase of SSA with increasing AOT occurs across the visible and near-infrared bands,suggesting the dominant negative/cooling effect with the elevated aerosol loading.The SSA spectra under varying AOT monotonically decrease with wavelength.The relatively large slope arises in summer,reinforcing the dominance of sulfate/nitrate aerosols that induce severe pollution in summer season around this city.

Application of biomonitoring and support vector machine in water quality assessment

The behavior of schools of zebrafish （Danio rerio） was studied in acute toxicity environments. Behavioral features were extracted and a method for water quality assessment using support vector machine （SVM） was de- veloped. The behavioral parameters of fish were recorded and analyzed during one hour in an environment of a 24-h half-lethal concentration （LC50） of a pollutant. The data were used to develop a method to evaluate water quality, so as 6＋ 2＋ to give an early indication of toxicity. Four kinds of metal ions （Cu2~, Hg2~, Cr , and Cd ） were used for toxicity testing. To enhance the efficiency and accuracy of assessment, a method combining SVM and a genetic algorithm （GA） was used. The results showed that the average prediction accuracy of the method was over 80% and the time cost was acceptable. The method gave satisfactory results for a variety of metal pollutants, demonstrating that this is an effective approach to the classification of water quality.