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191.
Tools for assisting human navigation, especially in-vehicle systems, have been extensively investigated. However, few studies have explored the design of speech-based over-the-phone guidance systems. This study examined the effect of landmarks' use and the effect of landmarks’ frames of reference in route instructions on navigation efficiency during map navigation tasks and satisfaction. Twenty-seven participants performed map navigation tasks using a simulated speech navigation system in three experimental conditions: instructions containing no landmarks, instructions containing landmarks located without reference to either the traveler’s body or the surrounding environment, and instructions containing landmarks located with respect to the traveler’s body. Navigation performances on maps were higher and landmarks enable participants to make fewer directional errors and find their routes more efficiently. Satisfaction levels and navigation performances were lower when instructions did not contain any landmarks. Landmarks’ frames of reference shifting turned out to be different between human-human situations previously used and human-computer situations used here.  相似文献   
192.
Changes of streamflow reflect combined effects of climate, soil and vegetation in the basin scale. This study was conducted to investigate the response of streamflow to the climate changes/variability in different scales of the Yellow River Basin (YRB). The spatial distribution and temporal trends were explored for precipitation and potential evapotranspiration (PE) during 1961-2000 to illustrate climate change/variability and impacts of climate change/variability on streamflow were explained by investigating the relationship of precipitation, PE and streamflow in the YRB. The results presented that: (i) precipitation and PE exhibited different spatial distribution patterns and temporal trends in different regions, and most stations showed negative trends for precipitation in the basin; (ii) the relationship of streamflow with precipitation and PE showed high nonlinearity, and the magnitudes and patterns of streamflow response to precipitation and PE displayed different patterns varied with the dry conditions in different region or years; and (iii) the precipitation elasticity of streamflow (?P) was 1.80, 1.08, 1.78 and 1.95 in Lanzhou, Toudaoguai, Huayuankou and Lijin respectively, while the PE elasticity of streamflow (?ET) was −3.41, −4.40, −4.52 and −4.20 in above four scales, respectively, from which can be seen that streamflow was more sensitive to precipitation in wet region than in arid region and inversely it was more sensitive to PE in arid regions than in wet regions. Furthermore, precipitation elasticity of streamflow calculated from the partial correlation presented a reasonable result to show the combined effect of precipitation and PE on streamflow.  相似文献   
193.
基于黄土高原1961—2008年月平均气温、最高气温、最低气温、相对湿度、降水量、风速和日照百分率等气候要素资料,应用修订的Penman-Monteith(P-M)模型计算了最大可能蒸散量,分析其时空分布、异常分布特征和次区域时间演变特征。结果表明:1961—2008年间,黄土高原最大可能蒸散量多年平均在400~800 mm之间,大部分区域650~750 mm之间。一致性异常分布是黄土高原最大可能蒸散量的最主要空间模态。黄土高原最大可能蒸散量的异常空间分布可分为以下3个关键区:高原西北部区、高原东北部区和高原东南部区。高原西北部区域最大可能蒸散量呈显著增加趋势,且发生了突变现象;高原东北部区域最大可能蒸散量呈显著下降的趋势,也发生了突变;而高原东南部区域下降趋势不显著,未发生突变。黄土高原最大可能蒸散量的3个空间分区中,3 a的周期振荡表现得比较显著。  相似文献   
194.
ABSTRACT: A model is developed for real-time operation of an irrigation reservoir with the objective of maximizing the value of multiple crop yields during a growing season. The model employs monthly additive and product forms of crop yield functions for dry matter and grain crops, respectively. The resulting nonlinear optimization model uses a log transform to reduce nonlinearities in the model. An application of the proposed model is compared to a common operating rule used in simulation models. The proposed model results were better in terms of net benefits from crop yields. The model uses GAMS (General Algebraic Modeling System) language. It requires an IBM-compatible microcomputer and is suitable for use by a reservoir manager.  相似文献   
195.
The impact of the management of packaging waste on the environment, economic growth and job creation is analyzed in this paper. This integrated assessment intends to cover a gap in the literature for this type of studies, using the specific case study of the Portuguese packaging waste management system (SIGRE).The net environmental benefits associated with the management of packaging waste, are calculated using the Life Cycle Assessment methodology. The results show that, for the categories studied, the impacts associated to SIGRE's various activities are surpassed by the benefits associated to material and energy recovery, with special focus on recycling. For example, in 2011 SIGRE avoided the emission of 116 kt CO2 equiv. – the equivalent carbon emission of the electricity consumption of 124.000 households in Portugal.The economic impact of SIGRE is evaluated through Input–Output Analysis. It was found that SIGRE's activities also have a significant economic impact. For example, their added value are ranked amongst the upper third of the economic activities with highest multiplier effect at national level: this means that for each Euro of value added generated within SIGRE, 1.25 additional € are added to the rest of the economy (multiplier effect of 2.25).Regarding the social impacts of SIGRE, the number of direct jobs associated with the system is estimated to be more than two thousand and three hundred workers. Out of these, 83% are connected to the management of municipal waste packaging (selective collection and sorting), 15% are connected to the management of non-municipal packaging waste and only 2% are connected to the Sociedade Ponto Verde (SPV, green dot society in English) – the management entity responsible for SIGRE.In general terms, the results obtained provide quantitative support to the EEA (2011) suggestion that moving up the waste hierarchy – from landfilling to recycling – creates jobs and boosts the economy.  相似文献   
196.
推动长三角一体化发展是着眼于实现“两个一百年”奋斗目标谋划部署的重大国家战略。本文首先解析了长三角一体化发展的新态势,提出了长三角一体化高质量发展的“四更”内涵,即更高战略定位的一体化、更高效率和水平的一体化、更加协调的一体化与更优空间形态的一体化。重点回顾总结了长三角一体化发展上升为国家战略三年多以来开展的主要行动和工作成效,按照高质量发展就是贯彻新发展理念的基本逻辑,构建了体现创新、协调、绿色、开放和共享五大理念的长三角一体化高质量发展评价指标体系,评估了2018—2020年长三角一体化高质量发展状态。对照一体化高质量发展新要求,针对目前存在问题,从空间部署和重点领域等方面提出相关路径建议,以期为推动长三角一体化更高质量发展提供决策参考。  相似文献   
197.
Potential evapotranspiration (PET) is an important component of water cycle. For traditional models derived from the principle of aerodynamics and the surface energy balance, its calculation always includes many parameters, such as net radiation, water vapor pressure, air temperature and wind speed. We found that it can be acquired in an easier way in specific regions. In this study, a new PET model (PETP model) derived from two empirical models of soil respiration was evaluated using the Penman-Monteith equation as a standard method. The results indicate that the PETP model estimation concur with the Penman-Monteith equation in sites where annual precipitation ranges from 717.71 mm to 1727.37 mm (R2 = 0.68, p = 0.0002), but show large discrepancies in all sites (R2 = 0.07, p = 0.1280). Then we applied our PETP model at the global scale to the regions with precipitation higher than 700 mm using 2.5° CMAP data to obtain the annual PET for 2006. As expected, the spatial pattern is satisfactory overall, with the highest PET values distributed in the lower latitudes or coastal regions, and with an average of 1292.60 ± 540.15 mm year−1. This PETP model provides a convenient approach to estimate PET at regional scales.  相似文献   
198.
Back in 1992, the Gulf of Aqaba Environmental Action Plan (GAEAP), a collaboration between the Aqaba Region Authority (ARA), Jordan and the World Bank, gave considerable emphasis to the environmental protection of the Gulf of Aqaba [The World Bank. Gulf of Aqaba Environmental Action Plan. Report No. 12244JO (1993).]. The document recommended the establishment of a marine reserve and the long term monitoring of the coastal habitats’ environmental quality. The combination of a dedicated follow up, the collaborative efforts of ARA and the Marine Science Station (MSS), and the founding of the Aqaba Special Economic Zone Authority (ASEZA) have turned the recommendations into reality. A comprehensive monitoring program of the Jordanian coastal habitats commenced in 1999. The first three years of the program were financed by a donation from The Global Environmental Facility (GEF). In return, Jordan has committed itself to the maintenance of the monitoring program as an ongoing tool for sustainable coastal management. The monitoring program includes observations on benthic habitat, fish communities, bottom sediments and seawater quality. This paper focuses on the results of seawater-quality monitoring in the first three years. Records of weather conditions, coastal currents, seawater temperature, transparency, salinity, density, pH, alkalinity, dissolved oxygen, ammonia, nitrate, nitrite, phosphate, silicate, particulate matter, chlorophyll a, zooplankton biomass, total coliform, fecal coliform, hydrocarbons and sedimentation rate have been generated monthly since January 1999 at six coastal stations, and one offshore reference station, in the Jordanian waters of the Gulf of Aqaba. The coastal stations are located at sites with different benthic habitats and are occupied by different human activities. Offshore records of density (thermohaline structure), nutrients and chlorophyll a depicted two well-defined seasons; a nutrient-/chlorophyll a-rich, mixed water winter from December to April and a nutrient-/chlorophyll a-poor, stratified water summer from June to October. Short transition seasons appeared in May and November. The mixing and stratification seasons were also clearly depicted in the coastal waters. Statistical analysis of the three-year data collected at the offshore station revealed no significant inter-annual differences in the upper 125 m of the water column with respect to any of the measured parameters. At coastal stations, the water quality at the two northernmost stations was significantly different in comparison to the upper 125 m at the offshore station and to the other coastal stations, with respect to the two key indicator parameters: inorganic nitrogen and chlorophyll a. The three-year findings of the monitoring program are employed to suggest standard codes of reference for the coastal water quality.  相似文献   
199.
Fish is the main food in coastal areas and its analysis for toxic metals has been used as an indicator of the pollution status of the aquatic environment. Several different fish species from the three Indian coasts, Visakhapatnam in the east, Mumbai in the west and Mangalore in the south west and also inland freshwater fish from Nagpur in the central region for comparison were analyzed for up to 20 elements (As, Au, Ba, Br, Cl, Co, Cr, Cu, Fe, Hg, K, Mn, Na, P, Rb, Sb, Sc, Se, Sr, Zn) by instrumental neutron activation analysis (INAA). Dried fish samples in powdered form were irradiated with thermal neutrons in a nuclear reactor followed by high resolution gamma ray spectrometry at different intervals. Several Reference Materials (RMs) of biological origin were analyzed for quality assurance and data validation. Elemental contents in different fish species vary in a wide range depending on the species, its size, location, and aquatic environment. Fish from Mangalore showed highest mean contents of Cr (14.8?±?29.9?µg?g?1), Cu (1005?±?643?µg?g?1) and Sb (849?±?888?ng?g?1) whereas those from Mumbai exhibited highest Hg (2066?±?2146?ng?g?1) and P (20.3?±?4.63?µg?g?1) but lowest Cu (6.30?±?3.10?µg?g?1) contents. Fish from all the regions showed significant amounts of nutrient elements such as Na, K, P, Mn, Fe, Se and Zn as well as some pollutant elements (Br, Cr, Sb, Hg). No regularity in variation of elemental contents with the size was observed. Prawn (Panaeus latisulcatus), a popular fish species from four different regions showed wide variation in elemental contents of Cr, Mn, Fe, Zn, Se, P including toxic pollutants, Sb and Hg. An attempt has been made to calculate daily dietary intake (DDI) for some nutrient elements from Indian fish. Elemental data for Cr, Cu, Fe, Hg, Se, and Zn have been compared with those from other fish exporting countries.  相似文献   
200.
作为陆面过程中地气相互作用的重要过程之一,蒸散发(Evapotranspiration,ET)在地球的大气圈-水圈-生物圈中发挥着重要作用。利用遥感-过程耦合模型BEPS,以中分辨率成像光谱仪(MODIS)数据和NCEP/NCAR再分析资料为主要输入,模拟分析了2007-2009年美国区域的地表ET,同时利用通量观测网AmeriFlux的站点观测数据验证该模型在ET模拟研究中的可靠性与适应。结果表明:12个站点通量实测值与BEPS模型模拟的ET值的相关系数为0.7297(P<0.05),表明BEPS模型能够较好的模拟研究区的地表ET。ET在1年内呈现明显的单峰趋势,5-9月ET值较高,可达60 mm·mon-1以上,最小值在1月份,值为8.39 mm·mon-1,最大值在7月份,值为118.04 mm·mon-1。该区域ET的平均年总量为505 mm·a-1。受地形、气候的影响,ET最高值对应于南部区域,这些地区ET的年总量普遍在600 mm·a-1以上,最高值为1667 mm·a-1,对应的主要覆被类型为草地和农田;中北部和东部的大部分区域ET年总量为400~600 mm·a-1;ET最小值在西部区域,年总量小于400 mm·a-1,对应覆被类型为疏林地和混交林。降水量与ET差值呈现从东向西逐渐递减的趋势,最小值主要分布在西部沙漠。整个研究区域ET与降水量之比的平均值为0.72,由东向西基本呈现增加趋势,在西部以及中北部的部分地区比值达到最大。  相似文献   
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