Size Of Buffer Zone Research Articles

Adjuvant use for the management of pesticide drift, leaching and runoff.

Adjuvants are included in many pesticide spray mixtures to enhance the performance of the applied chemical. Many adjuvants which modify the emulsion or extensional viscosity of the tank-mixture have been found to offer benefits in drift management, primarily by eliminating or reducing the 'Fine' droplets included in the spray with diameters <100-200 μm that can move off-target in unfavorable conditions during ground, airblast and aerial pesticide applications. Among wind tunnel and field studies conducted around the world, there is consensus that while some adjuvants are effective for drift management, the performance varies on a case-by-case basis, requiring verification for each adjuvant which could be achieved through a programme such as certification based on showing a reduction in Fine droplets and/or a reduction in airborne drift. These can be measured in wind tunnel studies according to international standards. This article provides a review of the current science in this subject area, from the approaches to data collection to a review of existing data and regulatory application for encouraging and rewarding the use of appropriate adjuvants that have been demonstrated to reduce airborne spray drift potential and therefore the size of no-spray buffer zones appropriate to protect nontarget sensitive areas from drift exposure. Some adjuvants can offer the same reduction in drift as offered by hooded sprayer retrofits. A drift reduction programme based on adjuvant use could include testing candidate adjuvants for their effect on droplet size and reduction in Fine droplets when sprayed through reference nozzles and compared against sprays without the adjuvant. Testing could also be based alternatively on measurements of drift potential on collectors such as monofilament line in wind tunnel or field studies. Once shown to be effective in reducing 'Fines' or spray drift, adjuvants could be certified and then referenced on pesticide labels and/or regulatory or best management practice schemes to encourage their use and offer reductions in use restrictions or no-spray buffer zone sizes based on drift management. Studies have shown that some adjuvants can reduce pesticide leaching into soils and contamination of groundwater, as well as runoff of active ingredients from plants into the environment. Performance depends on the adjuvant type, the pesticide with which it is used, the soil or plant type, the timing and mass of water input from rainfall and climatic factors. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Performance of Outbreak Management Plans for Emerging Plant Diseases: The Case of Almond Leaf Scorch Caused by Xylella fastidiosa in Mainland Spain.

Outbreak response to quarantine pathogens and pests in the European Union (EU) is regulated by the EU Plant Health Law, but the performance of outbreak management plans in terms of their effectiveness and efficiency has been quantified only to a limited extent. As a case study, the disease dynamics of almond leaf scorch, caused by Xylella fastidiosa, in the affected area of Alicante, Spain, were approximated using an individual-based spatial epidemiological model. The emergence of this outbreak was dated based on phylogenetic studies, and official surveys were used to delimit the current extent of the disease. Different survey strategies and disease control measures were compared to determine their effectiveness and efficiency for outbreak management in relation to a baseline scenario without interventions. One-step and two-step survey approaches were compared with different confidence levels, buffer zone sizes, and eradication radii, including those set by the EU legislation for X. fastidiosa. The effect of disease control interventions was also considered by decreasing the transmission rate in the buffer zone. All outbreak management plans reduced the number of infected trees (effectiveness), but large differences were observed in the number of susceptible trees not eradicated (efficiency). The two-step survey approach, high confidence level, and the reduction in the transmission rate increased the efficiency. Only the outbreak management plans with the two-step survey approach removed infected trees completely, but they required greater survey efforts. Although control measures reduced disease spread, surveillance was the key factor in the effectiveness and efficiency of the outbreak management plans. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

Online Three-Dimensional Bin Packing: A DRL Algorithm with the Buffer Zone

Abstract The online 3D bin packing problem(3D-BPP) is widely used in the logistics industry and is of great practical significance for promoting the intelligent transformation of the industry. The heuristic algorithm relies too much on manual experience to formulate more perfect packing rules. In recent years, many scholars solve 3D-BPP via deep reinforcement learning(DRL) algorithms. However, they ignore many skills used in manual packing, one of the most important skill is workers put the item aside if the item is packed improperly. Inspired by this skill, we propose a DRL algorithm with a buffer zone. Firstly, we define the wasted space and the buffer zone. And then, we integrate them into the DRL algorithm framework. Importantly, we compare the bin utilization with di erent thresholds of wasted space and di erent buffer zone sizes. Experimental results show that our algorithm outperforms existing heuristic algorithms and DRL algorithms.

Assessment of the Capability of Landsat and BiodivMapR to Track the Change of Alpha Diversity in Dryland Disturbed by Mining

Remotely sensed spectral diversity is a promising method for investigating biodiversity. However, studies designed to assess the effectiveness of tracking changes in diversity using historical satellite imagery are lacking. This study employs open-access multispectral Landsat imagery and the BiodivMapR package to estimate the multi-temporal alpha diversity in drylands affected by mining. Multi-temporal parameters of alpha diversity were identified, such as vegetation indices, buffer zone size, and the number of clusters. Variations in alpha diversity were compared for various plant communities over time. The results showed that this method could effectively assess the alpha diversity of vegetation (R2, 0.68). The optimal parameters used to maximize the accuracy of alpha diversity were NDVI threshold, 0.01; size of buffer zones, 120 m × 120 m; number of clusters, 100. The root mean square error of the alpha diversity of herbs was lowest (0.26), while those of shrub and tree communities were higher (0.34–0.41). During the period 1990–2020, the study area showed an overall trend of increasing diversity, with surface mining causing a significant decrease in diversity when compared with underground mining. This illustrates that the quick development of remote sensing and image processing techniques offers new opportunities for monitoring diversity in both single and multiple time phases. Researchers should consider the plant community types involved and select locally suitable parameters. In the future, the generation of long-time series and finer resolution maps of diversity should be studied further in the aspects of spatial, functional, taxonomic, and phylogenetic diversity.

도심 항공 모빌리티와 장애물 간의 감시장비 기반 충돌 위험도 평가모형

Urban Air Mobility is expected to resolve some problems in urban transportation such as traffic congestion and air pollution. Various studies for a large-scale commercialization of UAM are being actively conducted. To that end, the UAM Traffic Management system aims at securing a safety and an efficiency of UAM operations. In this study, a risk assessment model is proposed to evaluate the risk of collision between a vehicle and surrounding obstacles. The proposed model is conceived from the past studies for determining a proper separation distance between parallel runways for their independent operations. The model calculates the risk that the surveillance system fails to meet a target level of safety for a given buffer zone size between a designed route and surrounding obstacles. The model is applied to one of the routes proposed in K-UAM roadmap to evaluate its performances.

Assortative mixing in eastern spadefoot (Scaphiopus holbrookii) spatial networks is driven by landscape features

AbstractBiotic and abiotic factors drive assortative mixing (preference for or sorting with individuals with similar characteristics) in animal populations on a landscape, with implications for dispersal, population structuring, and other ecological and evolutionary processes. However, patterns and generative mechanisms of assortative mixing are overlooked in amphibians outside of specific life history events such as reproduction. The aims of this project were to determine whether there is assortative mixing by size and life history category in eastern spadefoots (Scaphiopus holbrookii), whether these patterns are preserved across time and spatial scale, and quantify the nature and relative role of various habitat and soil features in explaining observed patterns in spatial organization of individuals. We conducted field surveys in southeastern Virginia, USA, in 2016 and 2017 during nonbreeding periods to create spatial networks of S. holbrookii. We quantified spatial assortativity by size and life history stage and evaluated the roles of multiple landscape features in explaining spatial organization of S. holbrookii. We found that S. holbrookii sorted spatially by size and sex outside of breeding periods, with juveniles and adults less likely to sort with each other. Within each life history stage, S. holbrookii sorted by size. These patterns were similar across time and spatial scale. Soil and habitat types had no effect on assortativity. Instead, the distance to nearest breeding pool, wetland, and meadow were related to life history stage assortativity, as well as size assortativity in males and subadults. Adult males and females displayed affinity for breeding pools and meadows and avoidance of other types of wetlands, while subadults and nonbreeding adults showed opposite patterns compared with breeding adults. Our results indicate that (1) previously established guidelines for the minimum size of buffer zones to protect wetland‐breeding amphibians may be inadequate, (2) nonbreeding wetlands may be important core habitat for subadults, and (3) the upland spatial organization of amphibians may be used to predict locations of undetected breeding pools.

Editorial December 2021

This issue of the EPPO Bulletin shows an important part of the work of EPPO; Regional Standards in the area of phytosanitary regulation to control invasive plant pests. These Standards have been developed by experts in EPPO Panels, were extensively discussed, comments received from EPPO countries were considered and, in the end, the Working Party approved the Standards and the EPPO Council endorsed them. This process is facilitated by the EPPO Secretariat but relies on contributions of experts from EPPO’s member countries and ensures that the Standards are implementable, reflect reality, support NPPOs and thereby contribute to a harmonized way of working. The EPPO Council approved in September 2021 too many Standards to have them all published in this issue of the Bulletin. The EPPO Standards on efficacy evaluation of plant protection products in the PP1 series and three PM8 Standards on commodity-specific measures for forestry species, approved by Council this year, will be published in the April 2022 issue of the Bulletin. These Standards are available via online early view at https://onlinelibrary.wiley.com/toc/13652338/0/0. Moreover, EPPO’s Annual Report for 2020 in English is included, while the versions in French for 2020 and 2019 are available on the EPPO website, describing the whole range of EPPO’s work. The EPPO Standards in this issue include amongst others pest-specific Diagnostic Protocols, Standards for quality management and accreditation of laboratories, Standards on inspection of places of production and consignments of specific commodities and, a Standard on reducing the risk of soil from processing factories for potato cultivation. This latter Standard illustrates clearly how growers, processors and National Plant Protection Organizations (NPPOs) can take their respective responsibility and can work together to reduce risks of returning soil to farms. The role of NPPOs remains crucial. Another interesting subject is covered by the new Standard in the PM5 series on the design and implementation of a buffer zone to minimize the probability of spread of a pest into or out of regulated areas. This Standard gives guidance to risk assessors and risk managers to assess what size of buffer zone is matching their needs and possibilities. Moreover, a revision on the Standard on biological control agents, to clarify the criteria to list biological control agents safely used in the EPPO region, and Standards on control of invasive alien plants are included. The article on the developments in the work area of invasive alien plants over the past ten years in Europe gives a good overview of the work done in Europe on assessing, controlling, preventing and regulating IAP and the role EPPO played in this. Furthermore, this issue continues to contribute to pest reporting by including several reports on first findings which are important to signal new or changed risks, e.g. of the giant date mealy bug and the bay sucker in Jordan, Drosophila suzukii in the Russian Caucasus and scale insects and mealy bugs in Kenya. EPPO continues to work with many experts inside and outside the EPPO region to support NPPOs in their work to prevent the introduction and spread of pests and to control them. We have greatly appreciated the efforts of all experts to continue to contribute to EPPO’s work remotely due to COVID-19 restrictions. EPPO is, however, looking forward to working together during physical meetings in the near future. This will enhance the formal and informal discussions and exchange of information and EPPO can fulfil its role as a platform to experts to strengthen and enlarge their network.

Implication of Buffer Zones Delineation Considering the Landscape Connectivity and Influencing Patch Structural Factors in Nature Reserves

Since habitat fragmentation results in species losses worldwide, considering the influence of buffer zones on the maintenance of connectivity provides a new perspective for buffer delimitation. In our study, the implications of buffer zones around nature reserves were studied at four sites in Fuzhou from the perspective of landscape connectivity based on a distance threshold of 1 km. We applied Graph-based connectivity indices at the landscape level and patch level to reveal the overall connectivity and patterns of change in patch importance for maintaining connectivity with various buffer zones. Based on the results of these analyses, we showed the relationship between structural factors and changes in patch importance by Spearman correlation analysis and redundancy analysis. The results indicate that in the sites with smaller habitat proportion (HP), the connectivity is relatively lower, and the changes in patch importance will be greater when the buffer zone increases. Different buffer zone sizes are suggested in four sites to maximize its benefits. Relatively small patches with high shape complexity and close proximity to patches outside the boundary contribute greatly to connectivity by acting as stepping stones.

Summary data of home proximity to the nearest greenhouse (floricultural) crops and areas of greenhouse crops around various distances from homes in agricultural settings in Ecuador.

This article presents data of 623 children (1156 observations) between 4 and 17 years of age living in floricultural communities of Ecuador from 3 examination periods (2008, Apr 2016, and Jul–Oct 2016) as part of the study of Secondary Exposure to Pesticides among Children and Adolescents (ESPINA).We present geospatial data of residential distance to the nearest greenhouse crop and areas within various buffer sizes around homes of participants which is data used in the original research article: Suarez-Lopez JR, et al. “Residential proximity to greenhouse crops and pesticide exposure (via acetylcholinesterase activity) assessed from childhood through adolescence”. These geospatial variables are related but different constructs of the potential for off-target drift of pesticides from crops onto homes nearby (via acetylcholinesterase activity) Understanding the associations between these distance and crop area variables is important as a growing number of investigations are using these constructs of off-target pesticide drift to characterize their associations with both exposure biomarkers and outcome measures. Geographic positioning of greenhouses and homes were obtained using GPS receivers and satellite imagery. Distances between homes and the nearest greenhouse edge, and areas of greenhouse crops within various buffer zones (0–150 m, 151–300 m, 310–500 m, 501–750 m, and 751–1000 m) around homes were calculated using Geographic Information System software.Beyond the dataset, we present demographic and anthropometric characteristics, and indicators of pesticide exposure of participants across categories of areas of greenhouse crops around homes for buffer sizes of 0–150 m around homes. We also present the distribution of areas of flower crops within various buffer zone sizes around children's homes and the correlation coefficients between household proximity to the nearest treated greenhouse crops and areas of flower crops within various buffer zones within 1000 m of homes.

Reasonable Selection of Riparian Buffer Zone for the Reduction of Non-Point Sources Pollution in Coastal Area

Kim, J.M.; Lee, S.Y.; Baek, J.S.; Shin, H.S., and Kwon, S.C. 2019. Reasonable selection of riparian buffer zone for the reduction of non-point sources pollution in coastal area. In: Lee, J.L.; Yoon, J.-S.; Cho, W.C.; Muin, M., and Lee, J. (eds.), The 3rd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 91, pp. 256-260. Coconut Creek (Florida), ISSN 0749-0208.Studies are underway to improve the water qualities by introducing riparian buffers to existing rivers to manage nonpoint sources (NPSs) pollution, but they were not applied to prevent the inflow of land-based NPSs to coastal regions. Herein, we introduced methodological approach to the application of riparian buffer zones for mitigating NPSs at coastal regions, reflected by river-based simulation. We used hydrological simulation program–FORTRAN (HSPF) for the watershed of Unmun Dam, Korea, which can simulate the watershed hydrology with water quality for NPSs contaminated runoff including the fate and transport of pollutants in stream channels. We applied a riparian buffer to the prepared watershed, which is one of the best management practices, to estimate the reduction efficiency of NPSs according to the size of buffer zone. The model was calibrated and validated using four year records (2012-2015) in various scenario series. We obtained that decision coefficients (R2) were very good level for the flow rate and water quality, but biological oxygen demand (BOD), total nitrogen (TN), and total phosphate (TP) were generally not good. Instead, %difference was evaluated as very good level. Five scenarios (five different zone size of riparian buffer zone: 0.1 ha, 0.2 ha, 0.4 ha, 0.8ha, 1.6 ha) were investigated to determine its optimized zone size at the one site in the Unmun Dam Watershed. In Scenario 5 (1.6 ha), the efficiency reduction of TP was 82.329% when there was more than 30 mm of rainfall. However, simulation results showed lower efficiency of TN than expected, which illustrates that this result does not reflect the watershed's characteristics well. The efficiency of the reduction of NPSs pollution was greatly increased in Scenario 4 (0.8 ha). It is considered that the construction of more than 0.8 ha of riparian buffer in the watershed of Unmun Dam would be effective in reducing the NPSs pollution (BOD: >32.52%, TN: >20.68%), TP: >61.34%).

Introducing the “Derived Root-system Radius” – An attempt at an evidence-supported-calculation for calculation of buffer zone size in respect of Ancient Semi-natural Woodland, Ancient Trees & Veteran Trees

ABSTRACTGovernmental Standing Advice in England recommends a minimum 15 m buffer zone from Ancient Semi-natural Woodland (ASNW), or potentially longer distances for Ancient Trees (AT) and Veteran Trees (VT). This “one-size-fits-all” approach does not account for differences in the biology of individual tree species, or the environmental niches they occupy. The effective capillary range of trees further suggests that in some situations the Standing Advice potentially underestimates the zone of water influence. On the basis of published data linking root area to canopy spread, the estimated root areas of trees in a field sample (n = 112) were defined as the Derived Root-system Radius (DRSR). These results were significantly different from distances recommended within the Standing Advice, which might, therefore, be inadequate to safeguard the full extent of the roots in the greater proportion of the field study samples. In the case of AT and VT, the sensible approach will be to also anticipate any reduction in canopy area by applying both the diameter approach of the Standing Advice, and the DRSR, and adopting the greatest buffer zone.

Conservation buffer sizes derived from movement data of adult Cape vultures (Gyps coprotheres) in South Africa

The endangered Cape vulture (Gyps coprotheres) is facing a new emerging threat, e.g. wind energy development. Given their vulnerability to wind energy infrastructure, there is a necessity to establish proactive measures that could potentially mitigate future collisions, such as conservation buffers around breeding colonies and roost sites. This study used 50% kernel density estimates to estimate conservation potential for conservation buffer zone sizes for colonies. Our results indicate a buffer size of ±50 km to cover the core foraging range of the species around colonies.

Efficacy of reduced rate fumigant alternatives and methyl bromide against soilborne pathogens and weeds in western forest nurseries

Preplant soil fumigation is commonly used to control soilborne pathogens and weeds in forest seedling nurseries of Oregon and Washington. However, lower chemical inputs are desired to meet state and federal application regulations, to minimize buffer zone size requirements, and to help protect the environment. Therefore, the objectives of this research were to evaluate the efficacy of three reduced rate soil fumigants under totally impermeable film (TIF) in managing soilborne diseases and weeds, and to determine if combined applications of up to four biocontrol agents improved soilborne disease control. Reduced rates of methyl bromide, metam sodium, and 1,3-dichloropropene, all applied in combination with chloropicrin, were effective in decreasing soil populations of Pythium and Fusarium as well as the presence of Pythium in root debris from the previous crop. The roots of Douglas-fir (Pseudotsuga menziesii) seedlings transplanted into each fumigant treatment were also colonized less by Pythium and Fusarium than those transplanted into nonfumigated control plots. However, biocontrol treatments were not effective against either pathogen. Weed biomass and weeding times were also significantly reduced by fumigation. Application costs were similar for all three fumigant treatments, but seedling size was largest from the methyl bromide and metam sodium treatments followed by the 1,3-dichloropropene treatment. Based on the results of this study, reduced rates of methyl bromide, metam sodium, and 1,3-dichloropropene show promise in managing soilborne diseases and weeds in forest nurseries.

Placing invasive species management in a spatiotemporal context.

Invasive species are a worldwide issue, both ecologically and economically. A large body of work focuses on various aspects of invasive species control, including how to allocate control efforts to eradicate an invasive population as cost effectively as possible: There are a diverse range of invasive species management problems, and past mathematical analyses generally focus on isolated examples, making it hard to identify and understand parallels between the different contexts. In this study, we use a single spatiotemporal model to tackle the problem of allocating control effort for invasive species when suppressing an island invasive species, and for long-term spatial suppression projects. Using feral cat suppression as an illustrative example, we identify the optimal resource allocation for island and mainland suppression projects. Our results demonstrate how using a single model to solve different problems reveals similar characteristics of the solutions in different scenarios. As well as illustrating the insights offered by linking problems through a spatiotemporal model, we also derive novel and practically applicable results for our case studies. For temporal suppression projects on islands, we find that lengthy projects are more cost effective and that rapid control projects are only economically cost effective when population growth rates are high or diminishing returns on control effort are low. When suppressing invasive species around conservation assets (e.g., national parks or exclusion fences), we find that the size of buffer zones should depend on the ratio of the species growth and spread rate.

High Order Finite Difference Discretization for Composite Grid Hierarchy and Its Applications

AbstractWe introduce efficient approaches to construct high order finite difference discretizations for solving partial differential equations, based on a composite grid hierarchy. We introduce a modification of the traditional point clustering algorithm, obtained by adding restrictive parameters that control the minimal patch length and the size of the buffer zone. As a result, a reduction in the number of interfacial cells is observed. Based on a reasonable geometric grid setting, we discuss a general approach for the construction of stencils in a composite grid environment. The straightforward approach leads to an ill-posed problem. In our approach we regularize this problem, and transform it into solving a symmetric system of linear of equations. Finally, a stencil repository has been designed to further reduce computational overhead. The effectiveness of the discretizations is illustrated by numerical experiments on second order elliptic differential equations.

The Dry Season Shuffle: Gorges Provide Refugia for Animal Communities in Tropical Savannah Ecosystems.

In the wet-dry tropics, animal species face the major challenges of acquiring food, water or shelter during an extended dry season. Although large and conspicuous animals such as ungulates and waterfowl migrate to wetter areas during this time, little is known of how smaller and more cryptic animal species with less mobility meet these challenges. We fenced off the entire entrance of a gorge in the Australian tropical savanna, offering the unique opportunity to determine the composition and seasonal movement patterns of the small vertebrate community. The 1.7 km-long fence was converted to a trapline that was deployed for 18-21 days during the early dry season in each of two years, and paired traps on both sides of the fence allowed us to detect the direction of animal movements. We predicted that semi-aquatic species (e.g., frogs and turtles) would move upstream into the wetter gorge during the dry season, while more terrestrial species (e.g., lizards, snakes, mammals) would not. The trapline captured 1590 individual vertebrates comprising 60 species. There was a significant bias for captures on the outside of the fence compared to the inside for all species combined (outside/inside = 5.2, CI = 3.7-7.2), for all vertebrate classes, and for specific taxonomic groups. The opposite bias (inside/outside = 7.3, N= 25) for turtles during the early wet season suggested return migration heading into the wet season. Our study revealed that the small vertebrate community uses the gorge as a dry season refuge. The generality of this unreplicated finding could be tested by extending this type of survey to tropical savannahs worldwide. A better understanding of how small animals use the landscape is needed to reveal the size of buffer zones around wetlands required to protect both semi-aquatic and terrestrial fauna in gorges in tropical savannah woodland, and thus in ecosystems in general.

Carbon sequestration and riparian zones: Assessing the impacts of changing regulatory practices in Southern Brazil

Despite the consensus that riparian zones are important for the conservation of biological diversity and many other ecosystem services, there are no consistent regulations for how, or if, riparian areas should be used and the size of buffer zones required. Recently, controversial revisions to the Forest Code in Brazil have been implemented which include a reduction in the width of protected riparian buffer zones required along rivers. In order to model the impact of legislative changes on ecosystem services, we used the integrated valuation of environmental services and tradeoffs (InVEST) tool to assess a 30,000ha watershed in southern Brazil and carbon sequestration as an indicator for ecosystem services. The results demonstrate that the adoption of improved agriculture practices, development of secondary forests and especially the conversion of land into more restrictive types of land-use has a significant and positive impact on the levels of carbon sequestered. On the other hand, the easing of riparian zone requirements shows an important potential loss in carbon sequestration. More importantly, reducing the size of the buffer zone might result in land-conversion into agriculture or pasture, impacting both carbon sequestration and other ecosystem services. However, the easing of restrictions on riparian areas under the revised Forest Code might be overshadowed by changes to Legal Forest Reserve provisions which could have a much greater impact on carbon sequestration. Despite the restrictions imposed by various pieces of legislation, the loss of ecosystem services due to a reduction in the protected riparian area, as well as possible land conversion due to changes in Legal Forest Reserves, are possible unless efforts involving narrowing the gap between research and policy, effective law enforcement, and implementing attractive payment for ecosystem services programs, are put in place. We believe that introducing incentives to farmers to maintain the protection of riparian areas by implementing agroforestry systems, such as erva-mate (Ilex paraguariensis), would be beneficial socioeconomically and ecologically and should be integrated into the Forest Code.

Quantifying the impact of land cover composition on intra-urban air temperature variations at a mid-latitude city.

The effects of land cover on urban-rural and intra-urban temperature differences have been extensively documented. However, few studies have quantitatively related air temperature to land cover composition at a local scale which may be useful to guide landscape planning and design. In this study, the quantitative relationships between air temperature and land cover composition at a neighborhood scale in Beijing were investigated through a field measurement campaign and statistical analysis. The results showed that the air temperature had a significant positive correlation with the coverage of man-made surfaces, but the degree of correlation varied among different times and seasons. The different land cover types had different effects on air temperature, and also had very different spatial extent dependence: with increasing buffer zone size (from 20 to 300 m in radius), the correlation coefficient of different land cover types varied differently, and their relative impacts also varied among different times and seasons. At noon in summer, ∼37% of the variations in temperature were explained by the percentage tree cover, while ∼87% of the variations in temperature were explained by the percentage of building area and the percentage tree cover on summer night. The results emphasize the key role of tree cover in attenuating urban air temperature during daytime and nighttime in summer, further highlighting that increasing vegetation cover could be one effective way to ameliorate the urban thermal environment.

Fuzzy Optimization of Construction Engineering Project Schedule Based on Critical Chain Management

Critical chain management was the very important theory innovation in the development of construction project schedule management field in recent years. Compared with the traditional methods of construction project schedule management, the methods of critical chain management considered resource constraints into construction project schedule management, the construction project cycle was shortened and the efficiency was enhanced by using the dynamic thinking and circulation pattern to manage whole project. In view of the progress of critical chain management of the article, fuzzy theory was used to calculate and optimize the buffer zone sizes with the determination of the buffer size of the existing resources in certain critical chain management so as to shorten the cycle. DOI: http://dx.doi.org/10.11591/telkomnika.v11i12.3591 Full Text: PDF

Project Scheduling Optimization of Critical Chain Management Based on Fuzzy Theory

Critical chain management was the very important theory innovation in the development of the project schedule management field in recent years. Compared with the traditional project scheduling management, critical chain management considered resource constraints into the project schedule management, by using the dynamic thinking and circulation pattern to manage whole project, so as to shorten the project cycle and enhance the efficiency. In view of the progress of critical chain management of the article, combining the fuzzy mathematical theory, the existing resources in certain critical chain management is to calculate the buffer zone sizes with the determination of buffer size to shorten the cycle.