Improving the performance of genetic algorithms for land-use allocation problems     

Jonas Schwaab  Kalyanmoy Deb  Erik Goodman  Sven Lautenbach  Maarten J. van Strien  Adrienne Grêt-Regamey 《International journal of geographical information science》2018,32(5):907-930

Multi-objective optimization can be used to solve land-use allocation problems involving multiple conflicting objectives. In this paper, we show how genetic algorithms can be improved in order to effectively and efficiently solve multi-objective land-use allocation problems. Our focus lies on improving crossover and mutation operators of the genetic algorithms. We tested a range of different approaches either based on the literature or proposed for the first time. We applied them to a land-use allocation problem in Switzerland including two conflicting objectives: ensuring compact urban development and reducing the loss of agricultural productivity. We compared all approaches by calculating hypervolumes and by analysing the spread of the produced non-dominated fronts. Our results suggest that a combination of different mutation operators, of which at least one includes spatial heuristics, can help to find well-distributed fronts of non-dominated solutions. The tested modified crossover operators did not significantly improve the results. These findings provide a benchmark for multi-objective optimization of land-use allocation problems with promising prospectives for solving complex spatial planning problems.  相似文献   

Assessing hydrological changes in a regulated river system over the last 90 years in Rimac Basin (Peru)     

Vega-Jácome  Fiorella  Lavado-Casimiro  Waldo Sven  Felipe-Obando  Oscar Gustavo 《Theoretical and Applied Climatology》2018,132(1-2):347-362

Theoretical and Applied Climatology - Hydrological changes were assessed considering possible changes in precipitation and regulation or hydraulic diversion projects developed in the basin since...  相似文献   

Front Matter     

Sofus Christiansen  Sven Thostrup 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2013,113(1):I-IV

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The Changing Location of Service Activities in the Copenhagen Region     

Sven Illeris 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2013,113(1):120-131

Geografisk Tidsskrift, Danish Journal of Geography 97: 120–131, 1997.

The location of services in the Copenhagen region is described and analyzed. Six types of services are distinguished:

Local private and public services, serving the daily needs of the population, e.g. retailing, have suburbanized, closely following the distribution of population, though with a time-lag. The same goes for services which serve more special needs, e, g, hospitals.

Among producer services, some remain in the centre of Copenhagen, e.g. lawyer firms, partly for historical reasons, partly to minimize costs of face-to-face contacts with business partners. But contrary to traditional theory, most producer services are suburbanizing, mainly in order to find large sites and to improve their accessibility for cars. Some have shifted to the western suburbs to reduce costs (back offices) or to be close to the traffic arteries which connect Copenhagen with the rest of Denmark (wholesaling). Business services, e.g. engineering consultants, have primarily moved to the northern, amenity-rich suburbs, for reasons of prestige and of proximity to their high-status labour force. Still other services have located in a more hap-hazard way where they could find large areas, e.g. the airport and military establishments.  相似文献   

Snow accumulation in forests from ground and remote‐sensing data     

Angela Lundberg  Yuichiro Nakai  Hans Thunehed  Sven Halldin 《水文研究》2004,18(10):1941-1955

Winter‐forest processes affect global and local climates. The interception‐sublimation fraction (F) of snowfall in forests is a substantial part of the winter water budget (up to 40%). Climate, weather‐forecast and hydrological modellers incorporate increasingly realistic surface schemes into their models, and algorithms describing snow accumulation and snow‐interception sublimation are now finding their way into these schemes. Spatially variable data for calibration and verification of wintertime dynamics therefore are needed for such modelling schemes. The value of F was determined from snow courses in open and forested areas in Hokkaido, Japan. The value of F was related to species and canopy‐structure measures such as closure, sky‐view fraction (SVF) and leaf‐area index (LAI). Forest structure was deduced from fish‐eye photographs. The value of F showed a strong linear correlation to structure: F = 0·44 ? 0·6 × SVF for SVF < 0·72 and F = 0 for SVF > 0·72, and F = 0·11 LAI. These relationships seemed valid for evergreen conifers, larch trees, alder, birch and mixed deciduous stands. Forest snow accumulation (S_F) could be estimated from snowfall in open fields (S_o) and to LAI according to S_F = S_o (1 ? 0·11 LAI) as well as from SVF according to S_F = S_o (0·56 + 0·6 SVF) for SVF < 0·72. The value of S_F was equal to S_o for SVF values above 0·72. The value of sky‐view fraction was correlated to the normalized difference snow index (NDSI) using a Landsat‐TM image for observation plots exceeding 1 ha. Variables F and S_F were related to NDSI for these plots according to: F = ?0·37NDSI + 0·29 and S_F = S_o (0·81 + 0·37NDSI). These relationships are somewhat hypothetical because plot‐size limitation only allowed one sparse‐forest observation of NDSI to be used. There is, therefore, a need to confirm these relationships with further studies. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

To the origin of Icelandic rhyolites: insights from partially melted leucocratic xenoliths     

Andrey A. Gurenko  Ilya N. Bindeman  Ingvar A. Sigurdsson 《Contributions to Mineralogy and Petrology》2015,169(5):1-21

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Virtual Environments Begin to Embrace Process‐based Geographic Analysis          下载免费PDF全文

Hui Lin  Michael Batty  Sven E Jørgensen  Bojie Fu  Milan Konecny  Alexey Voinov  Paul Torrens  Guonian Lu  A‐Xing Zhu  John P Wilson  Jianya Gong  Olaf Kolditz  Temenoujka Bandrova  Min Chen 《Transactions in GIS》2015,19(4):493-498

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Complementing the European earth observation and geographic information body of knowledge with a business‐oriented perspective     

Barbara Hofer  Sven Casteleyn  Estefanía Aguilar‐Moreno  Eva‐Maria Missoni‐Steinbacher  Florian Albrecht  Rob Lemmens  Stefan Lang  Jochen Albrecht  Martyna Stelmaszczuk‐Grska  Glenn Vancauwenberghe  Aida Monfort‐Muriach 《Transactions in GIS》2020,24(3):587-601

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Can climate variability information constrain a hydrological model for an ungauged Costa Rican catchment?          下载免费PDF全文

Beatriz Quesada‐Montano  Ida K. Westerberg  Diana Fuentes‐Andino  Hugo G. Hidalgo  Sven Halldin 《水文研究》2018,32(6):830-846

Long‐term hydrological data are key to understanding catchment behaviour and for decision making within water management and planning. Given the lack of observed data in many regions worldwide, such as Central America, hydrological models are an alternative for reproducing historical streamflow series. Additional types of information—to locally observed discharge—can be used to constrain model parameter uncertainty for ungauged catchments. Given the strong influence that climatic large‐scale processes exert on streamflow variability in the Central American region, we explored the use of climate variability knowledge as process constraints to constrain the simulated discharge uncertainty for a Costa Rican catchment, assumed to be ungauged. To reduce model uncertainty, we first rejected parameter relationships that disagreed with our understanding of the system. Then, based on this reduced parameter space, we applied the climate‐based process constraints at long‐term, inter‐annual, and intra‐annual timescales. In the first step, we reduced the initial number of parameters by 52%, and then, we further reduced the number of parameters by 3% with the climate constraints. Finally, we compared the climate‐based constraints with a constraint based on global maps of low‐flow statistics. This latter constraint proved to be more restrictive than those based on climate variability (further reducing the number of parameters by 66% compared with 3%). Even so, the climate‐based constraints rejected inconsistent model simulations that were not rejected by the low‐flow statistics constraint. When taken all together, the constraints produced constrained simulation uncertainty bands, and the median simulated discharge followed the observed time series to a similar level as an optimized model. All the constraints were found useful in constraining model uncertainty for an—assumed to be—ungauged basin. This shows that our method is promising for modelling long‐term flow data for ungauged catchments on the Pacific side of Central America and that similar methods can be developed for ungauged basins in other regions where climate variability exerts a strong control on streamflow variability.  相似文献   

Evaluation and modification of some empirical and semi-empirical approaches for prediction of area-storage capacity curves in reservoirs of dams     

Issa E.Issa  Nadhir Al-Ansari  Govand Sherwany  Sven Knutsson 《国际泥沙研究》2017,32(1)

The storage capacity of reservoirs is gradually reduced due to sediment accumulation that causes changes in the area-storage capacity (ASC) curves.Establishing these curves and predicting their future change is an important issue for planners,designers and operators of dams.Many empirical and semiempirical approaches have been suggested for establishing and predicting the future changes for these curves.In this study four empirical and semi-empirical methods were evaluated and three of them were modified to be used for the prediction of changes in the ASC curves due to sedimentation,based on the existing sedimentation survey data for 11 reservoirs in the USK For evaluation,these approaches were reviewed and used to determine sedimentation depth and establishing the ASC curves for the Mosul dam reservoir (MDR),which is the biggest hydraulic structure on the River Tigris in northern Iraq.MDR started operating in 1986 with a storage capacity of 11.11 km3 and a water surface area 380 km2 at normal operation stage (330 m a.s.l.).The results obtained from these methods were evaluated using observed bathymetric survey data that had been collected in 2011 after 25 years of the operation of the dam.The evaluation results showed three methods had presented more accurate results for estimating water depth or sedimentation depth at dam site with percentage error about 1.06-3.30％.Whilst for establishing ASC curves,one method presented good agreement result with survey data.Furthermore,ASC and sedimentation depths at dam site of MDR for periods 50,75,100 and 125 years were estimated using the modified approaches and the area reduction method.The results of the modified methods provided reasonable agreement when compared with the area reduction method proposed by the U.S.Bureau of Reclamation and the agreement became better with an increase in time period.  相似文献