bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regional dimensionless hydrograph for Alberta foothills
Authors: Muzik Ivan , Chang Chiadih 
Published: December 2003

AbstractThe majority of hydrologic engineering applications deal with ungauged watersheds. Various empirical methods are available for synthesizing unit hydrographs for ungauged watersheds from information obtained from maps or field inspection of the watershed. An alternative to the employment of generalized synthetic unit hydrographs is to develop a regional dimensionless hydrograph to characterize the local rainfall‐runoff processes better. The derivation of such a dimensionless hydrograph is described for Alberta foothills, based on the analysis of 31 basins and 61 rainfall‐runoff events. The analysis shows that it is possible to derive a representative dimensionless hydrograph for the region with reasonable accuracy by averaging the observed direct runoff hydrographs converted into a dimensionless form. However, considerable uncertainty is associated with the estimation of the excess rainfall duration and the lag time of the events analysed. The lag time is the key parameter needed to convert the regional dimensionless hydrograph into an ungauged watershed unit hydrograph. Possible reasons for unexplained lag time variations are discussed. The regional dimensionless hydrograph developed and lag time curve were used to regenerate the original 61 hydrographs. Results were compared with the generalized Soil Conservation Service dimensionless unit hydrograph which tended to produce larger errors in predicted peak flows. Error analysis indicates the limits of accuracy that may be expected from the method. Copyright © 2003 John Wiley & Sons, Ltd.
Numerical modelling of ice‐jam flooding on the Peace–Athabasca delta
Authors: Beltaos Spyros 
Published: December 2003

AbstractIce jamming during the spring breakup of the ice cover in the lower reaches of the Peace River has been identified as the main agent of flooding and replenishment of the Peace–Athabasca delta (PAD) ecosystems. The relative rarity of major ice jams in the lower Peace River following construction of the Bennett Dam has resulted in serious habitat degradation and risk to local ecology, and concern has been raised over potential climate change impacts. This issue is under active study that encompasses use of various types of model, field data collection, and analysis of archived records. An important component of the study aims at determination of threshold flows that can result in significant flooding when a jam is in place in the PAD reach of the Peace. This question is investigated by means of RIVJAM, a numerical model that computes the water surface and thickness profiles of a jam in a given river reach. First, the model is calibrated using field data obtained during the 1996 and 1997 ice‐jam floods. Calibration coefficients are shown to be the same for both events and consistent with default values determined from previous applications in other rivers. A by‐product of the calibration process is the quantification of the flow reversals occurring under high‐stage conditions in the three major tributaries of the lower Peace. Next, the model is applied with increasing flow values and the resulting water surface profiles are compared with bank elevations. These comparisons indicate that an incoming flow of at least 4000 m3 s−1 is required to produce significant flooding of the delta. The calibrated model can also be used to examine the efficacy of controlled water releases at the Bennett Dam as a means of enhancing flooding potential. Copyright © 2003 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.
Phosphate retention in an agricultural stream using experimental additions of phosphate
Authors: Macrae M. L. , English M. C. , Schiff S. L. , Stone M. A. 
Published: December 2003

AbstractIn‐stream experiments involving additions of phosphate were conducted to determine the soluble reactive phosphorus (SRP) retention potential of a perennial first‐order stream that drains a 2·7 km2 agricultural catchment in southern Ontario. SRP retention was determined in relation to highly elevated SRP concentrations under low flow conditions. Point source treatments of phosphate were added to three reaches of this stream during two time periods when baseline SRP concentrations were notably different (early summer and early autumn). The reaches selected varied with respect to streambed shape and gradient, direction of groundwater flow, and channel vegetation type and density. One of the three experimental stream reaches was dredged between the two sampling periods, so that all vegetation and the top 25 cm of sediments were removed.SRP retention in the stream ranged from 0·8 to 24·1 µg m−2 s−1. Dredging the stream sediments did not alter the ability of the stream to remove SRP from the water column. SRP retention over the experimental reaches was generally 5–10% of the elevated concentration (0·7–4·2 mg l−1, a factor of 8–53 above pre‐experiment conditions), although low‐flow conditions in the stream were conducive to retention by stream sediments. Copyright © 2003 John Wiley & Sons, Ltd.
Cryptic wetlands: integrating hidden wetlands in regression models of the export of dissolved organic carbon from forested landscapes
Authors: Creed I. F. , Sanford S. E. , Beall F. D. , Molot L. A. , Dillon P. J. 
Published: December 2003

AbstractThis study examines the relationship between wetlands hidden beneath the forest canopy (‘cryptic wetlands’) and dissolved organic carbon (DOC) export to streams and lakes in forested ecosystems. In the Turkey Lakes Watershed (TLW), located in the Algoma Highlands of central Ontario, Canada, there is substantial natural variation in average annual DOC export (kgC ha−1 year−1), ranging from 11·4 to 31·5 kgC ha−1 year−1 in catchments with no apparent wetlands. We hypothesized that the natural variation in DOC export was related to cryptic wetlands. Cryptic wetlands were derived manually from geographic coordinates that were surveyed with a differential global positioning system, and automatically from identification of topographic depressions and flat slopes (<1·5° ) within a digital elevation model (DEM) in a geographic information system. For the TLW catchments, which are characterized by shallow soils over bedrock, a significant correlation (r2 ≥ 0·9, p < 0·001) between manual and automated methods was observed for scales up to 50 m when a light detection and ranging DEM was used for the topographic analysis. Regression models indicated that cryptic wetlands (%) explained the majority of the natural variation in DOC export (kgC ha−1 year−1), with r2 = 0·88 (p < 0·001) for the model based on the manually derived wetlands and r2 = 0·85 (p < 0·001) for the model based on the automatically derived wetlands. The strength and significance of the automatically derived wetlands (%) versus DOC export (kgC ha−1 year−1) regression model diminished when other sources of DEMs were used. This study emphasizes the importance of including cryptic wetlands in predictive models of DOC export, particularly in catchments where the topography includes depressions and flat areas but no apparent wetlands. Copyright © 2003 John Wiley & Sons, Ltd.
The effects of soil bulk density, clay content and temperature on soil water content measurement using time‐domain reflectometry
Authors: Gong Yuanshi , Cao Qiaohong , Sun Zongjia 
Published: December 2003

AbstractTime‐domain reflectometry (TDR) is increasingly used for field soil water estimation because the measurement is non‐destructive and less affected by soil texture, bulk density and temperature. However, with the increase in instrument resolution, the influences of soil bulk density and temperature on TDR soil moisture measurements have been reported. The influence is primarily caused by changes in soil and water dielectric permittivity when soil compaction and temperature varies. The objective of this study is to quantify the influence of soil bulk density and temperature, and to provide the corresponding correction methods. Data collected from sand, sandy loam, loam and clay loam show a linear relationship between the square root of dielectric constant of dry soil and bulk density, and a bulk density correction formula has been developed. The dielectric permittivity of soil solids estimated using this formula is close to that of oxides of aluminium, silicon, magnesium and calcium. Data collection from sandy loam show a noticeable decrease in measured soil moisture with increase in temperature when the volumetric soil water content is above 0·30 m3 m−3. A temperature‐correction equation has been developed, which could provide the corrected soil moisture based on soil temperature and TDR‐measured moisture. The effect of clay content has been detected, but it is not statistically significant. High clay contents cause the underestimation of soil water content in the low moisture range and overestimation of soil water content in the high moisture range. Copyright © 2003 John Wiley & Sons, Ltd.
Application of fuzzy logic to forecast seasonal runoff
Authors: Mahabir C. , Hicks F. E. , Fayek A. Robinson 
Published: December 2003

AbstractEach spring in Alberta, Canada, the potential snowmelt runoff is forecast for several basins to assess the water supply situation. Water managers need this forecast to plan water allocations for the following summer season. The Lodge Creek and Middle Creek basins, located in southeastern Alberta, are two basins that require this type of late winter forecast of potential spring runoff. Historically, the forecast has been based upon a combination of regression equations. These results are then interpreted by a forecaster and are modified based on the forecaster's heuristic knowledge of the basin. Unfortunately, this approach has had limited success in the past, in terms of the accuracy of these forecasts, and consequently an alternative methodology is needed.In this study, the applicability of fuzzy logic modelling techniques for forecasting water supply was investigated. Fuzzy logic has been applied successfully in several fields where the relationship between cause and effect (variable and results) are vague. Fuzzy variables were used to organize knowledge that is expressed ‘linguistically’ into a formal analysis. For example, ‘high snowpack’, ‘average snowpack’ and ‘low snowpack’ became variables. By applying fuzzy logic, a water supply forecast was created that classified potential runoff into three forecast zones: ‘low’, ‘average’ and ‘high’. Spring runoff forecasts from the fuzzy expert systems were found to be considerably more reliable than the regression models in forecasting the appropriate runoff zone, especially in terms of identifying low or average runoff years. Based on the modelling results in these two basins, it is concluded that fuzzy logic has a promising potential for providing reliable water supply forecasts. Copyright © 2003 John Wiley & Sons, Ltd.
Connectivity and storage functions of channel fens and flat bogs in northern basins
Authors: Quinton W. L. , Hayashi M. , Pietroniro A. 
Published: December 2003

AbstractThe hydrological response of low relief, wetland‐dominated zones of discontinuous permafrost is poorly understood. This poses a major obstacle to the development of a physically meaningful meso‐scale hydrological model for the Mackenzie basin, one of the world's largest northern basins. The present study examines the runoff response of five representative study basins (Scotty Creek, and the Jean‐Marie, Birch, Blackstone and Martin Rivers) in the lower Liard River valley as a function of their major biophysical characteristics. High‐resolution (4 m × 4 m) IKONOS satellite imagery was used in combination with aerial and ground verification surveys to classify the land cover, and to delineate the wetland area connected to the drainage system. Analysis of the annual hydrographs of each basin for the 4 year period 1997 to 2000, demonstrated that runoff was positively correlated with the drainage density, basin slope, and the percentage of the basin covered by channel fens, and was negatively correlated with the percentage of the basin covered by flat bogs. The detailed analysis of the water‐level response to summer rainstorms at several nodes along the main drainage network in the Scotty Creek basin showed that the storm water was slowly routed through channel fens with an average flood‐wave velocity of 0·23 km h−1. The flood‐wave velocity appears to be controlled by channel slope and hydraulic roughness in a manner consistent with the Manning formula, suggesting that a roughness‐based routing algorithm might be useful in large‐scale hydrological models. Copyright © 2003 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.
An assessment of global climate model‐simulated climate for the western cordillera of Canada (1961–90)
Authors: Bonsal Barrie R. , Prowse Terry D. , Pietroniro Alain 
Published: December 2003

AbstractClimate change is projected to significantly affect future hydrologic processes over many regions of the world. This is of particular importance for alpine systems that provide critical water supplies to lower‐elevation regions. The western cordillera of Canada is a prime example where changes to temperature and precipitation could have profound hydro‐climatic impacts not only for the cordillera itself, but also for downstream river systems and the drought‐prone Canadian Prairies. At present, impact researchers primarily rely on global climate models (GCMs) for future climate projections. The main objective of this study is to assess several GCMs in their ability to simulate the magnitude and spatial variability of current (1961–90) temperature and precipitation over the western cordillera of Canada. In addition, several gridded data sets of observed climate for the study region are evaluated.Results reveal a close correspondence among the four gridded data sets of observed climate, particularly for temperature. There is, however, considerable variability regarding the various GCM simulations of this observed climate. The British, Canadian, German, Australian, and US GFDL models are superior at simulating the magnitude and spatial variability of mean temperature. The Japanese GCM is of intermediate ability, and the US NCAR model is least representative of temperature in this region. Nearly all the models substantially overestimate the magnitude of total precipitation, both annually and on a seasonal basis. An exception involves the British (Hadley) model, which best represents the observed magnitude and spatial variability of precipitation. This study improves our understanding regarding the accuracy of GCM climate simulations over the western cordillera of Canada. The findings may assist in producing more reliable future scenarios of hydro‐climatic conditions over various regions of the country. Copyright © 2003 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.
Impact of meteorological predictions on real‐time spring flow forecasting
Authors: Coulibaly Paulin 
Published: December 2003

AbstractMeteorological predictions, such as precipitation and temperature, are commonly used to improve real‐time hydrologic forecasting, despite their inherent uncertainty and their absence in the model calibration stage. In this study, we quantify the effect of meteorological prediction errors on the accuracy of daily spring reservoir inflow forecasts using weather predictions in both the model calibration and testing phases. Different modelling experiments are compared using an operational conceptual model and nonlinear empirical models to assess the effects of using daily numerical weather predictions as opposed to the use of historical observations. It is found that, even with large prediction errors, meteorological forecasts can provide significant improvement of spring flow forecast for up to 7 days lead time, particularly for low flows. Spring flow prediction errors associated with the type of hydrological model used are significantly larger than those related to the meteorological predictions, particularly for 1 to 4 days ahead forecasts. The experimental results also indicate that multiple model‐based forecasting using an iterative prediction approach appears to be the most effective method for an adequate use of weather predictions. Copyright © 2003 John Wiley & Sons, Ltd.
A pose‐invariant approach for hypothesis support
Authors: Amador José J. 
Published: December 2003

AbstractThis article presents a tractable and empirically accurate algorithm realizing a midlevel visual process for pattern recognition. The algorithm takes advantage of hypotheses provided by a high‐level visual process, thereby, attempting to extract a region in an image based on these hypotheses. The main focus is to recognize quadrilateral as well as arbitrarily shaped objects from synthetic and real‐world images. The novel approach is based on a study of the Hough Transform and its generalized version. To show overall usefulness of the algorithm, an extensive series of experiments was performed. In particular, occlusion and multiple object‐instances were tested, indicating the effectiveness of this work's approach.© 2003 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 13, 201–207;2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.10056
A fast BNM (Best Neighborhood Matching): Algorithm and parallel processing for image restoration
Authors: Li Wen , Zhang David , Liu Zhiyong , Qiao Xiangzhen 
Published: December 2003

AbstractBest Neighborhood Matching (BNM) algorithm is a good approach of error concealment in terms of restored image quality. However, this kind of error concealment algorithm is commonly computation‐intensive, which restricts their real applications on large‐scale image or video sequence restoration. In this article, we propose a fast method, named Jump and look around Best Neighborhood Matching (JBNM), which reduces computing time to one sixth of that by BNM, while the quality of the restored images remains almost the same. To further reduce processing time and meet large‐scale image restorations, a parallel JBNM working on a cluster of workstations is proposed. Several critical techniques, including reading policy, overlap stripe data distribution, and communication strategies, have been developed to obtain high performance. Both theoretical analysis and experiment results indicate that our parallel JBNM provides an efficient technique for image restoration applications. © 2003 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 13, 189–200, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.10057
Automatic vergence control based on hierarchical segmentation of stereo pairs
Authors: Marfil R. , Urdiales C. , Rodríguez J. A. , Sandoval F. 
Published: December 2003

AbstractThis article presents a video system to focus an object of interest in the field of view by means of a stereo robotic head. The system relies on a new hierarchical segmentation technique that split the stereo pair into regions in a combined way. After segmentation is achieved, resulting regions in both images are implicitly related by a set of links and, consequently, their disparity can be estimated. Then, the cameras vergence is changed according to the estimated disparity until the object of interest is focused. The system has proven to be robust against mild noise and illumination changes. Its main advantage is that calibration is not a critical issue for the system to work. © 2003 Wiley Periodicals, Inc. Int J Imaging Syst Technol 13, 224–233, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.10058
A locally adaptive region growing algorithm for vascular segmentation
Authors: Yi Jaeyoun , Ra Jong Beom 
Published: December 2003

AbstractTo segment vascular structures in 3‐D CTA/MRA images, this article presents a new region growing algorithm based on local cube tracking. In the proposed algorithm, a small local cube is segmented to detect a vessel segment, and the following local cube(s) is determined based on the segmentation result. This procedure is repeated until the segmentation is completed. By confining the segmentation inside each local cube, a robust result can be obtained even in a tubular structure of steadily changing intensity. For segmentation, a locally adaptive and competitive region growing scheme is adopted to obtain well‐defined vessel boundaries. It should be emphasized that the proposed algorithm can detect all branches with practically acceptable computational complexity. In addition, its segmentation result is represented as a tree structure having many branches so that a user may easily correct the result branch‐by‐branch, if necessary. Experimental results from real images prove that the proposed algorithm produces prospective vessel segmentation results for 3‐D CTA/MRA images and segments vessels of various sizes well, including stenoses and aneurysms. © 2003 Wiley Periodicals, Inc. Int J Imaging Syst Technol 13, 208–214, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.10059
Image segmentation via local higher order statistics
Authors: Farhadi Ali , Shahshahani Mehrdad 
Published: December 2003

AbstractThe aim of this work is to present a method for the segmentation of images based on local higher order statistics. The algorithm can be applied for the separation of objects from a texture background and the segmentation of textures. The proposed technique makes no use of a data bank and its complexity is O(𝒩) where 𝒩 is the number of pixels. © 2003 Wiley Periodicals, Inc. Int J Imaging Syst Technol 13, 215–223, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.10069
Wear evaluation of cobalt–chromium alloy for use in a metal‐on‐metal hip prosthesis
Authors: St. John Kenneth R. , Zardiackas Lyle D. , Poggie Robert A. 
Published: December 2003

AbstractWear of the polyethylene in total joint prostheses has been a source of morbidity and early device failure, which has been extensively reported in the last 20 years. Although research continues to attempt to reduce the wear of polyethylene joint‐bearing surfaces by modifications in polymer processing, there is a renewed interest in the use of metal‐on‐metal bearing couples for hip prostheses. Wear testing of total hip replacement systems involving the couple of metal or ceramic heads on polymeric acetabular components has been performed and reported, but, until recently, there has been little data published for pin‐on‐disk or hip‐simulator wear studies involving the combination of a metallic femoral head component with an acetabular cup composed of the same or a dissimilar metal. This study investigated the in vitro wear resistance of two cobalt/chromium/molybdenum alloys, which differed primarily in the carbon content, as potential alloys for use in a metal‐on‐metal hip‐bearing couple. The results of pin‐on‐disk testing showed that the alloy with the higher (0.25%) carbon content was more wear resistant, and this alloy was therefore chosen for testing in a hip‐simulator system, which modeled the loads and motions that might be exerted clinically. Comparison of the results of metal‐on‐polyethylene samples to metal‐on‐metal samples showed that the volumetric wear of the metal‐on‐polyethylene bearing couple after 5,000,000 cycles was 110–180 times that for the metal‐bearing couple. Polyethylene and metal particles retrieved from either the lubricant for pin‐on‐disk testing or hip simulator testing were characterized and compared with particles retrieved from periprosthetic tissues by other researchers, and found to be similar. Based upon the results of this study, metal‐on‐metal hip prostheses manufactured from the high carbon cobalt/chromium alloy that was investigated hold sufficient promise to justify human clinical trials. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 68B: 1–14, 2004