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基于BP神经网络城市环境噪声预测及实证研究 总被引:1,自引:0,他引:1
城市噪声污染严重影响着人们的生活与工作,采用合适的方法对噪声污染进行评价并预测,进而提出有效的预防及治理措施是噪声污染防治的关键问题,文章利用灰色关联分析选取了影响环境噪声的主要因素,采用BP(Back propagation,BP)神经网络对北京市1994~2006年的环境噪声污染进行评价并预测,验证结果误差较小,说明基于灰色关联的BP神经网络能够有效地对城市环境噪声污染进行评价和预测。 相似文献
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为解决家用空调器噪声污染纠纷日益增多的问题,以一居民住宅楼为例,对家用空调噪声影响进行了监测与评价,并提出了防治措施。 相似文献
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兰州市交通噪声污染现状及评价 总被引:3,自引:1,他引:3
分析了兰州市交通噪声污染现状和危害,并运用模糊数学原理对兰州市交通噪声污染现状进行评价。得出兰州市总体交通噪声目前属于中度污染,在总结国内外城市交通噪声最新研究成果的基础上。提出了提高兰州市声环境质量的综合治理思路。 相似文献
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广州白云国际机场噪声污染评价 总被引:4,自引:0,他引:4
通过对广州白云国际机场噪声污染现状的分析和评价,表明,飞机起飞和降落时产生的噪声污染严重。地处航线下的荔湾区10多家中小学的教学活动、医院的医疗活动以及居民的生活、学习、工作由于飞机的频繁升降,均受到了不同程度的影响。对拟建的新白云国际机场噪声污染的预测表明,2005年在LWECPN>85dB环境下生活的人数约1.35万,80dB~85dB环境下生活的人数约2.3万,75dB~80dB环境下生活的人数约5.1万,70dB~75dB环境下生活的人数约10.1万。 相似文献
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Passy SI 《Environmental monitoring and assessment》2007,127(1-3):409-417
Diatom assemblages from 83 epilithic samples taken from the Mesta River, Bulgaria, were regressed against three sets of predictor
variables, i.e. environmental, spatial, and temporal. Redundancy analysis (RDA) of species and environmental data explained
36% of the diatom variance and extracted several important gradients of species distribution, associated with a downstream
increase in nutrient levels, pH, temperature, and organic pollution. The inclusion of spatial and temporal variables in the
RDA model captured additional 24% of the diatom variance and revealed three more gradients, a spatial gradient represented
by higher order polynomial terms of latitude and longitude, and two temporal gradients of annual and seasonal variation. Partial
RDAs demonstrated that the unique contribution of each predictor set to the explained diatom variance was the highest in the
spatial dataset (16%), followed by the environmental (9%), and the temporal (7%) datasets. The remaining 28% of the variance
was explained by the covariance of the predictor sets. This suggests that in biomonitoring of single stream basins, the cheap
and simple account of space and time would explain most of the variance in assemblage composition obviating the necessity
of expensive and time-consuming environmental assessments. The nature of the underlying environmental mechanisms can be easily
inferred from the diatom composition itself. 相似文献
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Monitoring morphological and vegetation changes and flow events in dryland river channels 总被引:1,自引:0,他引:1
Hooke JM 《Environmental monitoring and assessment》2007,127(1-3):445-457
Monitoring of impacts of floods in river valleys of dryland regions has become important with the onset and threats of desertification
and is likely to become even more vital with predictions of increased effects of climate and land use change. It is also needed
in order to conform to requirements of the EU Water Framework Directive. Monitoring in such regions sets particular challenges.
This paper explains a system of low-cost monitoring of changes in morphology, vegetation and sediment cover in channels and
valley floors of ephemerally flowing streams. It has been applied in SE Spain for 10 years and has proved very effective.
In particular, the use of simple crest-stage recorders for measuring flow height and the use of real-time differential GPS
for rapid and accurate survey and for relocating points have proved very valuable. Part of the monitoring is focused on the
interaction of plants and channel processes. Small changes in and around vegetation associated with flow events have been
detected by a combination of quadrat surveys and cross-profiling of the channel. A range of flow events has been measured
over the period of monitoring, demonstrating their differing effects and the varying sensitivity and responsiveness of different
sites. The sporadic occurrence of flood events in such an environment means that a strategy of monitoring several sites and
of continuation over many years has great benefits. 相似文献
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We describe the development and parameterization of a grid-based model of African savanna vegetation processes. The model
was developed with the objective of exploring elephant effects on the diversity of savanna species and structure, and in this
formulation concentrates on the relative cover of grass and woody plants, the vertical structure of the woody plant community,
and the distribution of these over space. Grid cells are linked by seed dispersal and fire, and environmental variability
is included in the form of stochastic rainfall and fire events. The model was parameterized from an extensive review of the
African savanna literature; when available, parameter values varied widely. The most plausible set of parameters produced
long-term coexistence between woody plants and grass, with the tree–grass balance being more sensitive to changes in parameters
influencing demographic processes and drought incidence and response, while less sensitive to fire regime. There was considerable
diversity in the woody structure of savanna systems within the range of uncertainty in tree growth rate parameters. Thus,
given the paucity of height growth data regarding woody plant species in southern African savannas, managers of natural areas
should be cognizant of different tree species growth and damage response attributes when considering whether to act on perceived
elephant threats to vegetation. 相似文献
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A study was carried out in a part of Palar and Cheyyar river basin to evaluate the current status of iron, manganese, zinc and atrazine concentrations, their origin and distribution in groundwater. Groundwater samples were collected during post-monsoon (March 1998 and February 1999) and pre-monsoon (June 1999) periods from 41 sampling wells distributed throughout the study area. The groundwater samples were analyzed for trace metals using AAS and atrazine using HPLC. The concentration of the trace elements in groundwater is predominant during pre-monsoon period. Distribution pattern indicates that the concentration of these elements increases from west to northeast and towards Palar river. Lower concentrations in the central part may be due to recharge of fresh water from the lakes located here. During most of the months, as there is no flow in Palar river, the concentrations of trace elements in groundwater are high. Drinking water standards indicate that Mn and Zn cross the permissible limit recommended by EPA during the pre-monsoon period. A comparison of groundwater data with trace element chemistry of rock samples shows the abundance of trace elements both in the rock and water in the order of Fe > Mn > Zn and Fe > Zn > Mn. This indicates that iron in groundwater is derived from lithogenic origin. Further, Fe, Mn and Zn have good correlation in rock samples, while it is reverse in the case of water samples, indicating the non-lithogenic origin of Mn and Zn. Atrazine (a herbicide) was not detected in any of the groundwater samples in the study area, perhaps due to low-application rate and adsorption in the soil materials. 相似文献
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Yazvenko SB McDonald TL Blokhin SA Johnson SR Meier SK Melton HR Newcomer MW Nielson RM Vladimirov VL Wainwright PW 《Environmental monitoring and assessment》2007,134(1-3):45-73
Exxon Neftegas Limited, operator of the Sakhalin-1 consortium, is developing oil and gas reserves on the continental shelf
off northeast Sakhalin Island, Russia. DalMorNefteGeofizika (DMNG), on behalf of the Sakhalin-1 consortium, conducted a 3-D
seismic survey of the Odoptu license area during 17 August–9 September 2001. A portion of the primary known feeding area of
the endangered western gray whale (Eschrichtius robustus) is located adjacent to the seismic block. The data presented here were collected as part of daily monitoring to determine
if there was any measurable effect of the seismic survey on the distribution and abundance of western gray whales. Mitigation
and monitoring program included aerial surveys conducted between 19 July and 19 November using the methodology outlined by
the Southern California High Energy Seismic Survey team (HESS). These surveys provided documentation of the distribution,
abundance and bottom feeding activity of western gray whales in relation to seismic survey sounds. From an operations perspective,
the aerial surveys provided near real-time data on the location of whales in and outside the feeding area, and documented
whether whales were displaced out of an area normally used as feeding habitat. The objectives of this study were to assess
(a) temporal changes in the distribution and abundance of gray whales in relation to seismic survey, and (b) the influence
of seismic survey, environmental factors, and other variables on the distribution and abundance of gray whales within their
preferred feeding area adjacent to Piltun Bay. Multiple regression analysis revealed a limited redistribution of gray whales
southward within the Piltun feeding area when the seismic survey was fully operational. A total of five environmental and
other variables unrelated to seismic survey (date and proxies of depth, sea state and visibility) and one seismic survey-related
variable (seg3d, i.e., received sound energy accumulated over 3 days) had statistically significant effects on the distribution and abundance
of gray whales. The distribution of two to four gray whales observed on the surface (i.e., about five to ten whales in total)
has likely been affected by the seismic survey. However, the total number of gray whales observed within the Piltun feeding
area remained stable during the seismic survey.
M. W. Newcomer, Deceased. 相似文献
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Marco Ferretti 《Environmental monitoring and assessment》1997,48(1):45-72
Part of this paper has been prepared for the lecture Forest Health Assessment-Criteria,Methods and Problems given by the author at the UIMPuniversity course Sanidad Forestal en el Bosques Mediterraneos yTemplados. Implicacion de la Contaminacion Atmosferica y del Cambio Global, held in Valencia, Spain, October, 1995. Assessment and monitoring of forest health representsa key point for environmental policy and for the management ofenvironmental resources. With the renewed interest in assessment andmonitoring of forest health generated by the suspected occurrence ofa widespread forest decline in Europe and North America, manyactivities have been undertaken: however, some questions should beconsidered and clarified when attempting to estimate forest health.Particularly, the objective(s) of the assessment and monitoringprogram should be carefully identified. Identification of a program‘stask has a number of implications and consequences: it implies adefinition of what concept of forest health (forest ecosystem health,forest health or forest trees health?) is assumed, what will be thetarget entity to be monitored, and therefore the identification of therelevant assessment questions and assessment endpoints.Consequences concern the definition of the spatial scale (frominternational to landscape and plot scale monitoring) and ecologicalcoverage (from single species population to population ofecosystems) of the program, which can have a considerable influenceon the choice of the proper sampling strategy and tactic, as well ason the most suitable methods, indicators and indices to be used.Although much of the work in the field of forest health and airpollution has concentrated on surveys on crown transparency anddiscoloration, there is an entire range of methods, indicators andindices developed to assess the health status of forests. The decisionas to which ones should be used will depend on the aim of theprogram and on economic and practical considerations. A furtherconsideration concerns the time span of the program, but anydecision in this field is subject to many limitations due to difficultiesin predicting future monitoring needs. All these points should becarefully considered and implemented according to a rigorousQuality Assurance procedure since any decision will influence futurework for many years. 相似文献
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Jamrah A Al-Futaisi A Prathapar S Harrasi AA 《Environmental monitoring and assessment》2008,137(1-3):315-327
This study aims to evaluate the potential of greywater availability in Muscat Governorate in the Sultanate of Oman, to establish
a methodology for greywater quantity estimation, to test greywater quality in order to assess reuse potential, and to examine
public acceptance for reuse.Total fresh water consumption and greywater generation from different household sources were measured
by water meters in five selected households during summer and winter. Additionally, a survey was designed and conducted in
five administrative areas of Muscat Governorate, with the objective of testing a methodology for estimating greywater generation
potential in these areas. Collected data were compared with that used by the Ministry of Housing, Electricity and Water, Sultanate
of Oman. The survey covered a total of 169 houses and 1,365 people. Greywater samples were collected and analyzed from showers,
laundries, kitchens and sinks in some of these households to determine their water quality parameters. Statistical analysis
results indicated that there is no significant variance in the total fresh water consumption between data used by the ministry
and those measured and estimated during this study, highlighting the applicability of the tested method. The study concluded
that the average per capita greywater generation rate is 151 Lpcd. Greywater production ranged from 80 to 83% of the total
fresh water consumption and most of the greywater is generated from showers. Further, 55 to 57% of the greywater generated
in a typical Omani household originated from the shower, 28 to 33% originated from the kitchen, 6 to 9% originated from laundry,
and 5 to 7% originated from sink, which constitutes approximately 81% of the total fresh water consumption. The physical,
chemical, and biological analyses of the grab samples revealed that greywater contains significant levels of suspended solids,
inorganic constituents, total organic carbon, chemical and biochemical oxygen demands, total Coliforms and Escherichia Coliform
bacteria. The public acceptance survey illustrated that approximately 76% of the respondents accepted the reuse of greywater
for gardening, 53% for car washing and 66% for toilet flushing. 相似文献
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Angehr GR Siegel J Aucca C Christian DG Pequeño T 《Environmental monitoring and assessment》2002,76(1):69-87
We developed an assessment and monitoring plan for birds in connection with the exploration and potential development of a large natural gas field in the Lower Urubamba drainage of Peru, a project of Shell Prospecting and Development Peru (SPDP). Our objectives were to: (1) inventory the birds in the area, including information on habitat use and abundance, and (2) devise long-term monitoring protocols for birds. We sampled birds through a combination of visual and auditory surveys and mist-netting at 4 well sites and 3 sites along the Urubamba and Camisea rivers. We recorded 420 speciesduring 135 days of field work. We consider the highest prioritiesfor a future monitoring program to be: (1) establish whether edge effects are occurring at well sites, along roads and alongthe planned pipeline route and determine the significance and extent of these effects and (2) assess the impact of increased human access to the area on game and other exploited species. The remoteness of the area, its rugged terrain and dense vegetation and the lack of trained personnel limit the choice of survey and monitoring methods. We recommend use of mist-netting and transects for monitoring edge effects and useof transects for monitoring game and other exploited species. 相似文献
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Operational and Design Considerations of a Trickling Filter for Ammonia Removal from Potable Water 总被引:1,自引:0,他引:1
We studied the steady-state behavior of a mathematical model of a nitrifying trickling filter. In particular, we studied the effect of the operating conditions of the filter on the complete and safe nitrification. We presented the results with the help of the operating diagram of the system and we determined the range of operating conditions resulting in optimal operation. We also computed biofilm thickness along the filter depth and concentration profiles inside the biofilm, and compared them with experimental results found in the literature. The comparison shows very good qualitative agreement between model predictions and experimental data. 相似文献