Themes and Challenges in Making Urban Freight Distribution Sustainable

The purpose of this article is to explore and classify themes and challenges in making urban freight distribution sustainable.The study has a cross sectional design which started by a narrative literature review and analysis of a sample of related literature(like peer-reviewed articles and EU(European Union)documents).It ended with complementary discussion and recommendation for tackling the challenges.The results of the study illustrate eight and seven emerged categories of themes and challenges,respectively.It is concluded that there is great need for a packet of mixed strategies as well as a more holistic perspective where all actors together analyse and design future set-ups and operation of urban freight distribution.Such a holistic view is essential in order to:understand how different actors of the chain look upon sustainable urban freight distribution,avoid sub-optimal policies/governing rules,and suggest close-to-reality solutions for tackling the challenges.Freight distribution in urban areas is the main focus of this article.In addition,the study is demarcated to eco/environmental aspect of sustainability although it is impossible to completely exclude its interaction with economic and social aspects.The results offered in this paper provide a systematic structure for classifying issues related to sustainable urban freight distribution;something which will be beneficial for managers and policy-makers when they approach sustainable supply chain management challenges.This study provides a synthesized classification of themes and challenges which can guide researchers,industries,authorities,and policy-makers in future sustainability efforts.

Multi-objective Dynamic Reconfiguration for Urban Distribution Network Considering Multi-level Switching Modes

The increasing integration of photovoltaic generators(PVGs) and the uneven economic development in different regions may cause the unbalanced spatial-temporal distribution of load demands in an urban distribution network(UDN). This may lead to undesired consequences, including PVG curtailment, load shedding, and equipment inefficiency, etc. Global dynamic reconfiguration provides a promising method to solve those challenges. However, the power flow transfer capabilities for different kinds of switches are diverse, and the willingness of distribution system operators(DSOs) to select them is also different. In this paper, we formulate a multi-objective dynamic reconfiguration optimization model suitable for multi-level switching modes to minimize the operation cost, load imbalance, and the PVG curtailment. The multi-level switching includes feeder-level switching, transformer-level switching, and substation-level switching. A novel load balancing index is devised to quantify the global load balancing degree at different levels. Then, a stochastic programming model based on selected scenarios is established to address the uncertainties of PVGs and loads. Afterward, the fuzzy c-means(FCMs) clustering is applied to divide the time periods of reconfiguration. Furthermore, the modified binary particle swarm optimization(BPSO)and Cplex solver are combined to solve the proposed mixed-integer second-order cone programming(MISOCP) model. Numerical results based on the 148-node and 297-node systems are obtained to validate the effectiveness of the proposed method.

Optimal Feeder Routing in Urban Distribution Networks Planning with Layout Constraints and Losses

We address the problem of optimally re-routing the feeders of urban distribution network in Milano,Italy,which presents some peculiarities and significant design challenges.Milano has two separate medium-voltage(MV)distribution networks,previously operated by two different utilities,which grew up independently and incoordinately.This results in a system layout which is inefficient,redundant,and difficult to manage due to different operating procedures.The current utility UNARETI,which is in charge of the overall distribution system,aims at optimally integrating the two MV distribution networks and moving to a new specific layout that offers advantages from the perspectives of reliability and flexibility.We present a mixed-integer programming(MIP)approach for the design of a new network configuration satisfying the so-called 2-step ladder layout required by the planner.The model accounts for the main electrical constraints such as power flow equations,thermal limits of high-voltage(HV)/MV substation transformers,line thermal limits,and the maximum number of customers per feeder.Real power losses are taken into account via a quadratic formulation and a piecewise linear approximation.Computational tests on a small-scale system and on a part of the Milano distribution network are reported.

Spatial distribution characteristics of urban thermal conditions: application of GIS and remote sensing

The urban thermal distribution characteristics and its variation are dynamically monitored and synthetically analyzed by using GIS technology. The meteorological satellite data serve as main information source, assisted as auxiliary information sources by the landsat satellite TM data, land use thematic maps and meteorological observed data. A correlated pattern on the ground surface brightness temperatures and air temperatures has been studied and established with good performance of application.

Bacterial Communities Associated with An Occurrence of Colored Water in An Urban Drinking Water Distribution System

This study aimed to investigate bacterial community in an urban drinking water distribution system （DWDS） during an occurrence of colored water. Variation in the bacterial community diversity and structure was observed among the different waters, with the predominance of Proteobacteria. While Verrucomicrobia was also a major phylum group in colored water. Limnobacter was the major genus group in colored water, but Undibacterium predominated in normal tap water. The coexistence of Limnobacter as well as Sediminibacterium and Aquobocterium might contribute to the formation of colored water.

Effectiveness of urban distributed runoff model for discharge and water depth calculation in urban drainage pipe networks

Effective urban land-use re-planning and the strategic arrangement of drainage pipe networks can significantly enhance urban flood defense capacity.Aimed at reducing the potential risks of urban flooding,this paper presents a straightforward and efficient approach to an urban distributed runoff model(UDRM).The model is developed to quantify the discharge and water depth within urban drainage pipe networks under varying rainfall intensities and land-use scenarios.The Nash efficiency coefficient of UDRM exceeds 0.9,which indicates its high computational efficiency and potential benefit in predicting urban flooding.The prediction of drainage conditions under both current and re-planned land-use types is achieved by adopting different flood recurrence intervals.The findings reveal that the re-planned land-use strategies could effectively diminish flood risk upstream of the drainage pipe network across 20-year and 50-year flood recurrence intervals.However,in the case of extreme rainfall events(a 100-year flood recurrence),the re-planned land-use approach fell short of fulfilling the requirements necessary for flood disaster mitigation.In these instances,the adoption of larger-diameter drainage pipes becomes an essential requisite to satisfy drainage needs.Accordingly,the proposed UDRM effectively combines land-use information with pipeline data to give practical suggestions for pipeline modification and land-use optimization to combat urban floods.Therefore,this methodology warrants further promotion in the field of urban re-planning.

Effect of traffic restriction on atmospheric particle concentrations and their size distributions in urban Lanzhou, Northwestern China

During the 2012 Lanzhou International Marathon, the local government made a significant effort to improve traffic conditions and air quality by implementing traffic restriction measures. To evaluate the direct effect of these measures on urban air quality, especially particle concentrations and their size distributions, atmospheric particle size distributions （0.5-20μm） obtained using an aerodynamic particle sizer （model 3321, TSI, USA） in June 2012 were analyzed. It was found that the particle number, surface area and volume concentrations for size range 0.5-10 μm were （15.0±2.1） cm-3, （11.8±2.6） μm2/cm3 and （1.9±0.6） μm2/cm3, respectively, on the traffic-restricted day （Sunday）, which is 63.2%, 53.0% and 47.2% lower than those on a normal Sunday. For number and surface area concentrations, the most affected size range was 0.5-0.7 and 0.5-0.8 μm, respectively, while for volume concentration, the most affected size ranges were 0.5-0.8, 1.7-2.0 and 5.0-5.4 μm. Number and volume concentrations of particles in size range 0.5-1.0μm correlated well with the number of non-CNG （Compressed Natural Gas） powered vehicles, while their correlation with the number of CNG-powered vehicles was very low, suggesting that reasonable urban traffic controls along with vehicle technology improvements could play an important role in improving urban air quality.

Similarities and differences of city-size distributions in three main urban agglomerations of China from 1992 to 2015： A comparative study based on nighttime light data

Comparing the city-size distribution at the urban agglomeration（UA） scale is important for understanding the processes of urban development. However, comparative studies of city-size distribution among China＇s three largest UAs, the Beijing-Tianjin-Hebei agglomeration（BTHA）, the Yangtze River Delta agglomeration（YRDA）, and the Pearl River Delta agglomeration（PRDA）, remain inadequate due to the limitation of data availability. Therefore, using urban data derived from time-series nighttime light data, the common characteristics and distinctive features of city-size distribution among the three UAs from 1992 to 2015 were compared by the Pareto regression and the rank clock method. We identified two common features. First, the city-size distribution became more even. The Pareto exponents increased by 0.17, 0.12, and 0.01 in the YRDA, BTHA, and PRDA, respectively. Second, the average ranks of small cities ascended, being 0.55, 0.08 and 0.04 in the three UAs, respectively. However, the average ranks of large and medium cities in the three UAs experienced different trajectories, which are closely related to the similarities and differences in the driving forces for the development of UAs. Place-based measures are encouraged to promote a coordinated development among cities of differing sizes in the three UAs.

Urban End Distribution Optimization Under E-Commerce Environment

With the rapid development of e-commerce, urban end distribution plays more and more important role in e-commerce logistics. The collection and delivery points(CDPs), between online retailers and customers,provide a way to improve the service quality of urban end distribution. But it will be more difficult to obtain an optimal solution of urban end delivery plan when many CDPs joint a complicated delivery network, since the solution space is always too large for many traditional heuristic algorithms to search. In this paper, a two-stage optimization method based on geographic information system(GIS) and improved cooperative particle swarm optimization(CPSO) is proposed. This method takes full advantage of powerful network analysis of GIS and strong global search of CPSO. A new cooperative learning mechanism, global sub-swarm, local sub-swarm and normal sub-swarm(GS-LS-NS), is used to improve the search mode of CPSO. Finally, several experiments are conducted to show the better performance of GIS-CPSO, compared with single PSO, GIS-CPSO and Arc GIS(software of GIS) separately. The conclusion of this research is much useful and applicable for logistics service providers.

WIND REGIME IN URBAN PLANNING AND INDUSTRIAL DISTRIBUTION

The function of wind regime in urban planning and general layout of industrial enter-prise is discussed. It is pointed out that if only the dominant wind direction is taken intoconsideration in urban planning and industrial distribution, undesirable layout may result.In regard to this some characteristics of the wind directions in monsoonal China are ana-lysed, a geographical regionalization is proposed and the patterns of urban land-use accord-ing to wind direction are discussed. Finally a new pollution coefficient is suggested.

Extracting urban areas in China using DMSP/OLS nighttime light data integrated with biophysical composition information

DMSP/OLS nighttime light （NTL） image is a widely used data source for urbaniza- tion studies. Although OLS NTL data are able to map nighttime luminosity, the identification accuracy of distribution of urban areas （UAD） is limited by the overestimation of the lit areas resulting from the coarse spatial resolution. In view of geographical condition, we integrate NTL with Biophysical Composition Index （BCl） and propose a new spectral index, the BCl Assisted NTL Index （BANI） to capture UAD. Comparisons between BANI approach and NDVl-assisted SVM classification are carried out using UAD extracted from Landsat TM/ETM＋ data as reference. Results show that BANI is capable of improving the accuracy of UAD extraction using NTL data. The average overall accuracy （OA） and Kappa coefficient of sample cities increased from 88.53% to 95.10% and from 0.56 to 0.84, respectively. Moreover with regard to cities with more mixed land covers, the accuracy of extraction results is high and the improvement is obvious. For other cities, the accuracy also increased to varying de- grees. Hence, BANI approach could achieve better UAD extraction results compared with NDVl-assisted SVM method, suggesting that the proposed method is a reliable alternative method for a large-scale urbanization study in China＇s mainland.

Atmospheric environmental capacity and urban atmospheric load in China's Mainland

Daily and annual average atmospheric environmental capacity coefficient(A-value) sequences for China's Mainland are calculated from hourly data recorded at 378 ground stations over 1975–2014. A-values at different recurrence intervals are calculated by fitting the sequences to Pearson type III distribution curves. Based on these A-values and source-sink balance(reference concentration 100 μg m^(-3)), atmospheric environmental capacities at the recurrence intervals are calculated for all of China's Mainland and each provincial administrative region. The climate average atmospheric environmental capacity reference value for the entire mainland is 2.169×10~7 t yr^(-1). An urban atmospheric load index is defined for analyses of the impact of population density on the urban atmospheric environment. Analyses suggest that this index is also useful for differentiating whether air quality changes are attributable to varying meteorological conditions or variations of artificial emission rate.Equations guiding the control of unorganized emission sources are derived for preventing air quality deterioration during urban expansion and population concentration.

Comparison of aerosol characteristics during haze periods over two urban agglomerations in China using CALIPSO observations

Using CALIPSO （cloud-aerosol lidar and infrared pathfinder satellite observation） vertical observation data during haze periods from January 2007 to December 2008, we analyzed differences in aerosol char- acteristics near the surface, as well as in the middle troposphere between the Beijing-Tianjin-Hebei metropolitan region （Area A） and the Yangtze River Delta region （Area B） in China. One significant dif- ference was that haze pollution in Area A was related to local and non-local aerosols, while in Area B it was related to local anthropogenic sources. In all seasons apart from autumn, aerosol pollution in Area A was more severe than in Area B, both near the surface and at higher altitudes, In Area A, non-spherical aerosols were dominant from 0 to 4 km in spring, summer, and winter; while in autumn, there were con- siderably high numbers of non-spherical aerosols below 0.5 km, and near-spherical aerosols from 0.5 to 4 km. In Area B, both near-spherical and non-spherical aerosols were common in all seasons. Moreover, aerosols with attenuated color ratios of 0-0.2 were more common in all seasons in Area A than in Area B, indicating that fine particle pollution in Area A was more serious than in Area B. Finally, relatively large aerosols linked to gravity settling appeared more frequently near the surface in Area A than in Area B.

考虑双重不确定性的公交时刻表分布鲁棒优化模型

城市公交系统由于受外界干扰,其需求和运行环境在时空上呈现高度不确定性,给日常运营组织带来了巨大挑战.为增强公交系统对于客流需求和运行场景双重不确定性的应对能力,提出一种权衡服务质量和服务鲁棒性的单一线路时刻表优化方法.方法采用离散场景集刻画需求的不确定性,并以滞留人数的期望值和条件风险值最小化为目标,综合考虑多方面约束,构建多场景耦合的分布鲁棒优化模型(DRO).为方便模型求解,运用模糊集描述场景发生概率的不确定性,再借助对偶理论和常规线性化方法将原模型转化为等价的混合整数线性规划形式.最后通过实际案例对方法进行分析,结果表明:等价转换得到的线性形式可由GUROBI优化软件快速求得最优解;DRO模型所得时刻表能有效应对双重不确定性;随着不确定性的上升,分布鲁棒优化方法相较于传统随机规划方法体现出更强的鲁棒性,可以切实改善公交系统运营的稳定性.

Pollutant concentrations and pollution loads in stormwater runoff from different land uses in Chongqing

To investigate the distribution of pollutant concentrations and pollution loads in stormwater runoff in Chongqing,six typical land use types were selected and studied from August 2009 to September 2011.Statistical analysis on the distribution of pollutant concentrations in all water samples shows that pollutant concentrations fluctuate greatly in rainfall-runoff,and the concentrations of the same pollutant also vary greatly in different rainfall events.In addition,it indicates that the event mean concentrations （EMCs） of total suspended solids （TSS） and chemical oxygen demand （COD） from urban traffic roads （UTR） are significantly higher than those from residential roads （RR）,commercial areas （CA）,concrete roofs （CR）,tile roofs （TRoof）,and campus catchment areas （CCA）;and the EMCs of total phosphorus （TP） and NH3-N from UTR and CA are 2.35-5 and 3 times of the class-III standard values specified in the Environmental Quality Standards for Surface Water （GB 3838-2002）.The EMCs of Fe,Pb and Cd are also much higher than the class-III standard values.The analysis of pollution load producing coefficients （PLPC） reveals that the main pollution source of TSS,COD and TP is UTR.The analysis of correlations between rainfall factors and EMCs/PLPC indicates that rainfall duration is correlated with EMCs/PLPC of TSS for TRoof and TP for UTR,while rainfall intensity is correlated with EMCs/PLPC of TP for both CR and CCA.The results of this study provide a reference for better management of non-point source pollution in urban regions.