Model Generation

administration of NPY inhibits limbic seizure activity induced by kainic acid or electrical hippocampal stimulation in vivo. Similarly, antiepileptiform effects have been demonstrated in hippocampal slice models. This suggests a possible antiepileptic potential of NPYergic agonists in future treatment of complex partial seizures in humans. To further characterize the antiepileptic potential of NPY, the effects of NPY administered i.c.v. were studied on seizures induced by subcutaneous injection of pentylenetetrazole (PTZ), a widely used antiepileptic screening test believed to model generalized myoclonic seizures. NPY significantly and dose-dependently inhibited PTZ-induced clonic seizures as revealed by increases in seizure latencies. In addition, NPY caused an overall significant reduction in the number of rats developing tonic seizures and in mortality following PTZ, indicating that NPY also reduces seizure severity. By demonstrating antiepileptic activity of NPY in yet another seizure model, this study further adds to the concept of NPY receptors as potentially novel targets in future treatment of seizure disorders. Specifically, antiepileptic effects in the PTZ model suggest that NPYergic agonists might also prove active against human myoclonic seizures.

Diffusion of mass in a solid cylinder with concentration dependent diffusivity (or temperature-dependent thermal conductivity in case of heat diffusion) does not admit of an analytical solution except in special cases. The 'shrinking core model' has been used to develop an approximate analytical solution in certain circumstances. The model, generally useful to describe heterogeneous solid-fluid reactions, is applied to theoretically analyze the adsorption-diffusion phenomena of methylene blue dye in a glass fiber in the present work. Theoretical equations have been derived for the case of diffusivity as an exponential function of concentration. The diffusivity parameters are evaluated by global minimization of the error between the experimental and the theoretical concentration history. Other forms of diffusivity, namely constant diffusivity and diffusivity varying linearly with concentration are found to involve larger errors. A parametric sensitivity analysis of the error has been done. The shrinking core model could satisfactorily interpret the experimental dye concentration profile in the substrate.

Cybercity Modeler (CC-Modeler) is a semi-automated generator for 3-D objects of built-up environments. Given the primary data as point clouds measured on Analytical Plotters or Digital Stations, CC-Modeler presents a new method for fitting planar structures to the measured sets of point clouds. While this topology generator has been originally designed to model buildings, it can also be used for other objects, which may be approximated by polyhedron surfaces. We have used it so far for roads, rivers, parking lots, ships, etc. CC-Modeler is a generic topology generator. The problem of fitting planar faces to point clouds is treated as a Consistent Labeling problem, which is solved by probabilistic relaxation. Once the faces are defined and the related points are determined, a simultaneous least squares adjustment is applied in order to fit the faces jointly to the given measurements in an optimal way. We first present the processing flow of CC-Modeler. Then, the algorithm of structuring the 3-D point data is outlined. Finally, we show the results of several data sets that have been produced with CC-Modeler. Also, reference is made to a new concept for a spatial information system (CC-SIS, CyberCity Spatial Information System)which is currently under development.

Infrared and collinear safe event shape distributions and their mean values are determined using the data taken at five different centre of mass energies above M Z with the DELPHI detector at LEP. From the event shapes, the strong coupling α s is extracted in O(α 2 s ), NLLA and a combined scheme using hadronisation corrections evaluated with fragmentation model generators as well as using an analytical power ansatz. Comparing these measurements to those obtained at M Z , the energy dependence (running) of α s is accessible. The logarithmic energy slope of the inverse strong coupling is measured to be dα −1 s d log(E cm ) = 1.39 ± 0.34(stat) ± 0.17(syst) , in good agreement with the QCD expectation of 1.27.

A spatial decision support system (SDSS) was designed to help forestry planners take into consideration aboriginal land uses in eastern Canada. This SDSS permits the comparison between different harvest scenarios based on four criteria: wood procurement, accessibility, wildlife habitat and land use. Each criterion is evaluated through a set of indicators calculated by mathematical models. The SDSS operates as ArcGis9.x extension and allows one to measure spatial parameters used to calculated economic and land use indicators.

This paper explores the return volatility predictability inherent in high-frequency speculative returns. Our analysis focuses on a refinement of the more traditional volatility measures, the integrated Õolatility, which links the notion of volatility more directly to the return variance over the relevant horizon. In our empirical analysis of the foreign exchange market the integrated volatility is conveniently approximated by a cumulative sum of the squared intraday returns. Forecast horizons ranging from short intraday to 1-month intervals are investigated. We document that standard volatility models generally provide good forecasts of this economically relevant volatility measure. Moreover, the use of highfrequency returns significantly improves the longer run interdaily volatility forecasts, both in theory and practice. The results are thus directly relevant for general research methodology as well as industry applications. q 1999 Elsevier Science B.V. All rights reserved. JEL classification: C15; C22; G15

Résumé Cet article présente un modèle de croissance schumpetérien, qui géné-ralise la théorie existante : nous utilisons la différenciation circulaire du modèle de Salop [1979] pour prendre en compte le fait que la connaissance se diffuse, avec plus ou moins d'ampleur, entre les ...

This study presents the significance of the currency crises, discusses the related literature and applies a model of economic vulnerability to Turkey during 1985Q2-2004Q2. The common approach in currency crisis literature is to focus on the performance of ...

The aim of this study is to examine the association between sense of community, walking, and neighborhood design characteristics. The current study is based on a sub-sample of participants (n ¼ 609) from the US Atlanta SMARTRAQ study who completed a telephone survey capturing physical activity patterns, neighborhood perceptions, and social interactions. Objective measures of neighborhood form were also computed. Univariate and multivariate models (General Linear Models (GLM)) were used to examine the association between sense of community (SofC) and aspects of the built environment, physical activity, and neighborhood perceptions. In multivariate models the impact on SofC was examined with progressive adjustment for demographics characteristics followed by walking behavior, neighborhood design features, neighborhood perceptions and time spent traveling in a car.

Within the (E-)Power research program a new approach for supporting the chain of processes from the creation of legal texts to the implementation of normative (juridical) information systems has been developed. According to this approach cre- ating formal knowledge models starts with the analysis of the legal text. This process executed by knowledge analysts is very time consuming. Within the

Fast magnetic resonance imaging slice acquisition techniques such as single shot fast spin echo are routinely used in the presence of uncontrollable motion. Current applications involve fetal MRI and MRI of moving subjects and organs. Although high-quality slices are frequently acquired by these techniques, inter-slice motion leads to severe motion artifacts that appear in out-of-plane views. Slice sequential acquisitions do not enable 3D volume representation. In this study, we have developed a novel technique based on a slice acquisition model, which enables the reconstruction of a volumetric image from multiple-scan slice acquisitions. The super-resolution volume reconstruction is formulated as an inverse problem of finding the underlying structure generating the acquired slices. We have developed a robust M-estimation solution which minimizes a robust error norm function between the model-generated slices and the acquired slices. The accuracy and robustness of this novel technique has been quantitatively assessed through simulations with digital brain phantom images as well as high-resolution newborn images. We also report here successful application of our new technique for the reconstruction of volumetric fetal brain MRI from clinically acquired data.

The sibling model is often one of the best methods for calculating preseason forecasts of adult return abundance (recruits) for populations of Pacific salmon Oncorhynchus spp. This model forecasts abundance of a given age-class for a given year based on the abundance of the previous age-class in the previous year. When sibling relations fit historical data well, the sibling model generally performs better than other forecasting methods, such as stockrecruitment models. However, when sibling relations are weak, better forecasts are obtained by other models, such as naïve models that simply use an historical average. We evaluated the performance of a hybrid model that used quantitative criteria for switching between a sibling model and a naïve model when generating forecasts for 21 stocks of chum salmon O. keta and 37 stocks of sockeye salmon O. nerka in the northeastern Pacific Ocean. Compared with the standard sibling model, the hybrid model reduced the root mean square error (RMSE) of forecasts by an average of 27% for chum salmon stocks and 28% for sockeye salmon stocks. Compared with a naïve model, the hybrid model reduced the RMSE of forecasts by an average of 16% for chum salmon stocks and 15% for sockeye salmon stocks. Our results suggest that hybrid models can improve preseason forecasts and management of these two species.

This study presents the significance of the currency crises, discusses the related literature and applies a model of economic vulnerability to Turkey during 1985Q2-2004Q2. The common approach in currency crisis literature is to focus on the performance of thresholds for a set of early warning indicators. Following the explanation of "Index of Speculative Pressure" (ISP), Granger causes of the ISP is discussed. The study shows that, current account/ GDP ratio, M2/international reserves ratio, real credit growth and current account/foreign direct investment ratio are Granger causes of the ISP at 1 % level. Then by using Vector Auto Regression (VAR) model, the ISP index is forecasted. The study shows that the combination of VAR(1)+VAR(2)+VAR(5) models generate relatively better forecast values than all other single models. Finally the study estimates dynamic probit and logit models by using maximum likelihood to predict currency crises. It shows that logit model gives a better performance than the probit, for a better prediction of the probabilities of the Turkish currency crises. The most important contribution of this study is to show that the logit model has a very high performance in the prediction of Turkish currency crises. It can be used to foresee forthcoming currency crises. Also the forecast of the ISP (as a level) is giving very successful results. It is observed that the ISP and forecasted ISP values are almost moving together or very close to each other. JEL Classification: C25, E44, F3, F47.

Complex models generated e.g. with a laser range scanner often consist of several thousand or million triangles. For efficient rendering this high number of primitives has to be reduced. An important property of mesh reduction - or simplification - algorithms used for rendering is the control over the introduced geometric error. In general, the better this control is, the slower the simplification algorithm becomes. This is especially a problem for out-of-core simplification, since the processing time quickly reaches several hours for high-quality simplification. In this paper we present a new efficient algorithm to measure the Hausdorff distance between two meshes by sampling the meshes only in regions of high distance. In addition to comparing two arbitrary meshes, this algorithm can also be applied to check the Hausdorff error between the simplified and original meshes during simplification. By using this information to accept or reject a simplification operation, this method all...

Microsimulation attempts to describe economic and social events by modelling the behaviour of individual agents. These models have proved useful in evaluating the impact of policy changes at the micro level. Spatial microsimulation models contain geographic information and allow for a regional or local approach to policy analysis. This paper builds on previous work on urban systems by employing similar modelling techniques for the analysis of rural areas . SYNTHESIS-a synthetic spatial information system for urban and regional analysis: methods and examples. Environment and Planning A 20, 1645-1671. Exploring microsimulation methodologies for the estimation of household attributes. microsimulation for local labour market policy analysis. Computers, Environment and Urban Systems 24, 305-330; Ballas, D., Clarke, G. P., 2001a. Modelling the local impacts of national social policies: a spatial microsimulation approach. Environment and Planning C: Government and Policy 19, 587-606; Ballas, D., Clarke, G. P., 2001b. Towards local implications of major job transformations in the city: a spatial microsimulation approach. Geographical Analysis 33, 291-311]. It describes the development of the simulation model for the Irish local economy (SMILE) model. SMILE is a static and dynamic spatial microsimulation designed to analyse the impact of policy change and economic development on rural areas in Ireland. This paper focuses on the static model. First, we describe the European and Irish policy environment and indicate the importance of building spatial models to analyse change in rural Ireland. Second, we review existing literature on regional and local modelling techniques and the use of spatial models as tools for policy analysis. Third, we describe the SMILE static model. The model generates synthetic spatially referenced population for the Irish Republic at the small area level-the population micro data is produced for district electoral divisions (DEDs). Finally, we show how data from other sources can be linked to the static model output. We link data from the Irish National Farm Survey on farm system, income and off-farm employment of operator to the SMILE static model. We use this example to show its potential as a tool for policy analysis. r

Lipoxygenases (LOXs) are a group of enzymes involved in the oxygenation of polyunsaturated fatty acids. Among these 5-lipoxygenase (5-LOX) is the key enzyme leading to the formation of pharmacologically important leukotrienes and lipoxins, the mediators of inflammatory and allergic disorders. In view of close functional similarity to mammalian lipoxygenase, potato 5-LOX is used extensively. In this study, the homology modeling technique has been used to construct the structure of potato 5-LOX. The amino acid sequence identity between the target protein and sequence of template protein 1NO3 (soybean LOX-3) searched from NCBI protein BLAST was 63%. Based on the template structure, the protein model was constructed by using the Homology program in InsightII. The protein model was briefly refined by energy minimization steps and validated using Profile-3D, ERRAT and PROCHECK. The results showed that 99.3% of the amino acids were in allowed regions of Ramachandran plot, suggesting that the model is accurate and its stereochemical quality good. Like all LOXs, 5-LOX also has a two-domain structure, the small N-terminal b-barrel domain and a larger catalytic domain containing a single atom of non-heme iron coordinating with His525, His530, His716 and Ile864. Asn720 is present in the fifth coordination position of iron. The sixth coordination position faces the open cavity occupied here by the ligands which are docked. Our model of the enzyme is further validated by examining the interactions of earlier reported inhibitors and by energy minimization studies which were carried out using molecular mechanics calculations. Four ligands, nordihydroguaiaretic acid (NDGA) having IC 50 of 1.5 lM and analogs of benzyl propargyl ethers having IC 50 values of 760 lM, 45 lM, and no inhibition respectively were selected for our docking and energy minimization studies. Our results correlated well with the experimental data reported earlier, which proved the quality of the model. This model generated can be further used for the design and development of more potent 5-LOX inhibitors.

Objective. The overall response, load transmission, role of ligaments, and state of stress in various components under varus-valgus moments in the intact and collateral-deficient tibiofemoral joint are investigated. Design. A non-linear finite element model consisting of bony structures (tibia and femur), their articular cartilage layers, medial and lateral menisci and four primary ligaments (cruciates and collaterals) is utilized. Background. Valgus and varus stresses are among the primary mechanisms of injury to knee ligaments. Several in vitro studies have investigated the role of ligaments in resisting such loads and on the way deficiency in either collateral may affect the response. Methods. Cartilage layers are isotropic while menisci are non-homogeneous composite. The articulation of cartilage layers with each other and with the intervening menisci and the wrapping of the medial collateral ligament around the tibia1 edge are treated as large displacement frictionless contact problems. The non-linear elastostatic response of the joint at full extension is computed under varus-valgus moments applied to the femur with the tibia fixed. Cases simulating deficiency in collaterals and constraint on femoral axial rotation are also studied. Results. The response is non-linear with large coupled axial rotations, internal in varus and external in valgus. In intact and collateral-deficient states, the joint shows varus or valgus openings so that the articulation occurs at one plateau only, medial in varus and lateral in valgus. Large tensile forces in cruciates in collateral-cut models generate higher compression penalty on the loaded plateau. Conclusions. Collaterals are the primary load-bearing structures; their absence would substantially increase primary laxities, coupled axial. rotations, forces in cruciates, and articular contact forces. Good agreement with measurements is found. Relevance Detailed knowledge of joint biomechanics is essential in the diagnosis, prevention and treatment of observed disorders. Absence of collateral ligaments increases the loads in cruciates and contact stresses transmitted through cartilage layers and menisci, and thus places the affected components at more risk, especially when varus-valgus is accompanied by other modes of loading as well.

Physically based models are commonly used as an integral step in landslide hazard assessment. Geomorphic principles can be applied to a broad area, resulting in first order assessment of landslide susceptibility. New techniques are now available that may result in the increased accuracy of such models. We investigate the possibility to enhance landslide susceptibility modeling by integrating two physically-based landslide models, the Factor of Safety (FS) and the Shallow Stability model (SHALSTAB), with traditional empirical-statistical methods that utilize terrain attribute information derived from a digital elevation model and land use characteristics related to forest harvesting. The model performance is measured by the area under the receiver operating characteristic curve (AUROC) and sensitivity at 90% and 80% specificity both estimated by bootstrap resampling. Our study examines 278 landslide initiation points in the Klanawa Watershed located on Vancouver Island, British Columbia, Canada. We use a generalized additive model (GAM)and a logistic regression model (GLM) combining physical landslide models, terrain attributes and land use data, and GAMs and GLMs using only subsets of these variables.In this study, all empirical and combined physical-empirical models outperformthe physically-based models, with GAMs often performing significantly better than GLMs. The strongest predictive performance is achieved by the GAMsusing terrain attributes in combination with land use data. Variables representing physically-based models do not significantly improve the empirical models, but they may allow for a better physical interpretation of empirical models. Also, based on bootstrap variable-selection frequencies,land use data, FS, slope and plan/profile curvature are relatively the most important predictor variables.

The ability to understand and predict the flight trajectory of a sports ball is important in many fields of sports engineering. The aerodynamic coefficients of sports balls have been studied in detail and yet aerodynamic models generally assume that spin rates are constant during flight. This study examines the spin decay of sports balls in flight in order to improve the accuracy of aerodynamic models. Several types of sports ball (tennis ball, worn tennis ball, football, oversize tennis ball) were launched in a sports hall using artificial bowlers at various speeds and spin rates. The start and end of the trajectories were filmed using two high speed video cameras and the resulting measurements were used to assess the spin decay of each ball as well as the factors affecting spin decay. The data shows a strong linear relationship between spin decay and the product of initial spin and speed for all the different sports balls tested. However, the constant in this linear relationship was found to be different for each of the different balls and was assumed to be dependent on the physical attributes of the different balls. Dimensionless parameters were derived such that the differences between the sports ball spin characteristics could be more easily identified. It was found that the rate of spin decay is largely dependent on the balls moment of inertia; however, its surface roughness and its boundary layer flow regime are also of importance.

This paper analyzes the links between corporate tax avoidance and the growth of highpowered incentives for managers. We develop a simple model that highlights the role of feedback effects between tax sheltering and managerial diversion in determining how highpowered incentives influence tax sheltering decisions. Then, we construct an empirical measure of corporate tax avoidance -the component of the book-tax gap not attributable to accounting accruals -and investigate the link between this measure of tax avoidance and incentive compensation. We find that increases in incentive compensation tend to reduce the level of tax sheltering, in a manner consistent with a complementary relationship between diversion and sheltering. In addition, consistent with a prediction of our model, we find some evidence suggesting that this negative effect is driven primarily by a subsample of firms with relatively weak governance institutions. Our results may help explain the "undersheltering puzzle," and why large book-tax gaps are associated with subsequent negative abnormal returns.

In September 2009, Tropical Storm Ketsana (local name: TS Ondoy) hit the Manila metropolitan area (Metro Manila) and brought an anomalous volume of rain that exceeded the Philippines’ forty-year meteorological record. The storm caused exceptionally high and extensive flooding. Part of this study was a survey conducted along the stretch of the Marikina River, one of the major rivers that flooded. Post event resident interviews were used to reconstruct the flooding in the absence of stream gauge data. Hydraulic and hydrologic modeling were carried out to understand the mechanism that brought the flood. Peak floods occurred at different hours along the river resulting from the transmission of water from the main watershed to the downstream areas. Modeled peak flood and flood timing coincided well with actual observations except for downstream stations where actual peak floods were observed to have occurred at a later time. Compounding factors such as other flood sources and stream back...

Numerical weather prediction (NWP) models generally exhibit systematic errors in the forecast of near-surface weather parameters due to a wide number of factors, including poor resolution of model topography, or deficient physical parameterizations. In this work, deviations between 2 m-temperature observations and forecasts provided by the European Centre for Medium-Range Weather Forecasts (ECMWF) are analysed at 12 synoptic stations located in Portugal. Systematic errors vary considerably with geographical location and time of day as well as throughout the year. The Kalman Filter theory provides a suitable tool to correct systematic errors of this type and therefore improve model forecasts. Accordingly, a Kalman Filter is applied to 2 m-temperature forecasts issued in 2003, a year marked by one of the most severe heat waves in Europe. It is shown that the developed methodology is versatile in adapting its coefficients to different seasons and weather conditions. The proposed Kalman Filter allows an objective forecast correction for 2 m-temperature, reducing the bias of the forecasts at each station to values close to zero, and improving the root mean square error from 10% up to over 70%, with respect to the raw ECMWF forecasts.

This paper presents an overview of simulation-based shop floor control. Much of the work described herein is based on research conducted in the Computer Integrated Manufacturing (CIM) Lab at The Pennsylvania State University, the Texas A&M Computer Aided

This paper analyses the demand for petroleum products in India. For this purpose, econometric models based on time series data are generated for individual products so as to capture product specific factors affecting demand. The models generated follow the non-homothetic translog functional form. The models are validated against historical data by testing them for expost forecast accuracy.

This paper proposes to combine a heuristic technique and an algorithmic one to provide a method to reverse engineer the generalization/specialization links hidden in a relational database. The heuristic phase combines the exploration of three sources: DDL specifications, DML specifications and data to provide information, such as inclusion links and existence constraints. This information is then used by the algorithm

Diatoms from the genus Achnanthidium are abundant in rivers, streams, and springs of the Appalachian Mountains. They inhabit clean and polluted waters, including those affected by acid mine drainage. The identification of Achnanthidium taxa is difficult due to their small cell size and insufficient information in the diatom floras. We studied the taxonomy and ecology of Achnanthidium in Appalachian rivers by analyzing a data set of benthic diatom samples and corresponding water chemistry data collected during several water-quality surveys from 181 sampling sites. Ten species were identified using scanning electron and light microscopy: A. alpestre (Lowe & Kociolek) Lowe & Kociolek, A. atomus (Hustedt) Monnier, Lange-Bertalot, & Ector, A. deflexum (Reimer) Kingston, A. duthii (Sreenivasa) Edlund, A. eutrophilum (Lange-Bertalot) Lange-Bertalot, A. cf. gracillimum (Meister) Lange-Bertalot, A. cf. latecephalum Kobayasi, A. minutissimum (Ku¨tzing) Czarnecki (sensu lato), A. reimeri (Camburn) comb. nov., and A. rivulare Potapova & Ponader.

Relational Data Base Management Systems (RDBMS) are currently the most popular database management systems. The relational model is a simple and powerful model for representing real world applications. However, it lacks the expressiveness of conceptual models. Unlike the latter, the relational model does not offer the generalization abstraction. Therefore, it does not allow the designer to represent directly a large

The dynamic adsorption capacity calculated from the breakthrough curves progressively decreased with the increases in the face velocity, suggesting that the effect of intraparticle diffusion and possibly the rate of adsorption as the rate-limiting mechanism were increasingly more profound for a chemical filter-type adsorber configuration. The YooneNelson model generally matched well with the experimental breakthrough curved for breakthrough fraction less than 50%. However, the proportionality constant in the YooneNelson model needed modification through the method from which the mass transfer coefficient (k v ) in the WheelereJonas equation is determined. Subsequently, a series of breakthrough curves for the hypothetical toluene concentrations and face velocities simulating realistic operating conditions was generated, and their validity was verified against the adsorption capacity predicted by the Dubinin eRadushkevich isotherm equation. The useful life of a chemical filter could henceforth be estimated with confidence using the breakthrough curves predicted by the modified YooneNelson model.

This paper deals with the steady-state behaviour of an M/G/1 queue with an additional second phase of optional service subject to breakdowns occurring randomly at any instant while serving the customers and delayed repair. This model generalizes both the classical M/G/1 queue subject to random breakdown and delayed repair as well as M/G/1 queue with second optional service and server breakdowns. For this model, we first derive the joint distributions of state of the server and queue size, which is one of chief objectives of the paper. Secondly, we derive the probability generating function of the stationary queue size distribution at a departure epoch as a classical generalization ofPollaczek-Khinchin formula. Next, we derive Laplace Stieltjes transform of busy period distribution and waiting time distribution. Finally, we obtain some important performance measures and reliability indices of this model. Choudhury and Paul [5] investigated such a model under Bernoulli feedback mechanism. In this context Krishnakumar and Arivudainambi in [6] obtained the explicit expression for transient probabilities for this type of finite capacity model M/G/1/1 Bernoulli feedback queue and M/G/1/1 queue with unreliable server . Recently, Wang [8] investigated such a model with the assumption that the server is subject to breakdowns and repairs, and some critical reliability indices are obtained. More recently, Ke [9] extended the result for a multi-optional service system where concept of setup time is also introduced.

This paper focuses on commonalities and differences between the two mixed-signal hardware description languages VHDL-AMS and Verilog-AMS in the case of modeling heterogeneous or multi-discipline systems. The paper has two objectives. The first one consists of modeling the structure and the behavior of an airbag system using both the VHDL-AMS and the Verilog-AMS languages. Such a system encompasses several time abstractions (i.e. discrete-time and continuous-time), several disciplines, or energy domains (i.e., electrical, thermal, optical, mechanical, and chemical), and several continuous-time description formalisms (i.e., conservative-law and signal-flow descriptions). The second objective is to discuss the results of the proposed modeling process in terms of the descriptive capabilities of the VHDL-AMS and Verilog-AMS languages and of the generated simulation results. The tools used are Advance-MS from Mentor Graphics for VHDL-AMS and AMS Simulator from Cadence Design Systems for Verilog-AMS. The paper shows that both languages offer effective means to describe and simulate multi-discipline systems, although using different descriptive approaches. It also highlights current tool limitations since full language definitions are not yet supported.

In recent years the use of species distribution models by ecologists and conservation managers has increased considerably, along with an awareness of the need to provide accuracy assessment for predictions of such models. The kappa statistic is the most widely used measure for the performance of models generating presence-absence predictions, but several studies have criticized it for being inherently dependent on prevalence, and argued that this dependency introduces statistical artefacts to estimates of predictive accuracy. This criticism has been supported recently by computer simulations showing that kappa responds to the prevalence of the modelled species in a unimodal fashion. 2. In this paper we provide a theoretical explanation for the observed dependence of kappa on prevalence, and introduce into ecology an alternative measure of accuracy, the true skill statistic (TSS), which corrects for this dependence while still keeping all the advantages of kappa. We also compare the responses of kappa and TSS to prevalence using empirical data, by modelling distribution patterns of 128 species of woody plant in Israel.

This paper presents a multiple linear regression model developed for describing global river export of sediments (suspended solids, TSS) to coastal seas, and approaches for estimating organic carbon, nitrogen, and phosphorous transported as particulate matter (POC, PN, and PP) associated with sediments. The model, with river-basin spatial scale and a 1-year temporal scale, is based on five factors with a significant influence on TSS yields (the extent of marginal grassland and wetland rice, Fournier precipitation, Fournier slope, and lithology), and accounts for sediment trapping in reservoirs. The model generates predictions within a factor of 4 for 80% of the 124 rivers in the data set. It is a robust model which was cross-validated by using training and validation sets of data, and validated against independent data. In addition, Monte Carlo simulations were used to deal with uncertainties in the model coefficients for the five model factors. The global river export of TSS calculated thus is 19 Pg yr À1 with a 95% confidence interval of 11-27 Pg yr À1 when accounting for sediment trapping in regulated rivers. Associated POC, PN, and PP export is 197 Tg yr À1 (as C), 30 Tg yr À1 (N), and 9 Tg yr À1 (P), respectively. The global sediment trapping included in these estimates is 13%. Most particulate nutrients are transported by rivers to the Pacific ($37% of global particulate nutrient export), Atlantic (28-29%), and Indian ($20%) oceans, and the major source regions are Asia ($50% of global particulate nutrient export), South America ($20%), and Africa (12%).

This paper describes the simulation studies of a 3-Ø self-excited asynchronous generator (SEASG) fed RL load in conjunction with an AC/DC/AC converter fed series RLC circuit. An attempt has been made to analyze the current, drawn by the rectifier circuit due to changes in the inverter frequency and their effects on the terminal voltage of the generator have been studied in open loop control. The frequency variation of the inverter fed series RLC circuit emulate the phenomenon of an inductive, capacitive reactance and resistive effect at the point of common coupling (PCC) of the generator terminal. This methodology could be used to inject leading / lagging VAR into the self-excited induction generator network (stand alone power generator), used to extract the power from wind, solar, Mini/Micro hydro energy sources. The proposed system has been simulated using power system tool box in Matlab/Simulink software. An attempt has been made to study the performances of SEASG using simulation. The results have been discussed and also presented.

This paper discusses the practical use of filtering and inversion in VLF-EM data processing and interpretation. The advantages and disadvantages of both mentioned techniques were outlined to avoid the misleading interpretation of such data in some case studies. Much concern is taken to show the interval distance effect upon the correct depth identification of the anomalous body by either inversion or filtering. The methodology of the study is going through proposing an initial model, generating the synthetic VLF-EM data of the model by means of forward modeling, filtering (Karous-Hjelt filter) and inversion (Inv2DVLF software) of the synthetic data and comparing between the results of both methods and the initial model. The study reached to (1) Karous-Hjelt filter provides misleading depths for his limited depth of resolution and cannot provide estimates of deep targets if the profile is too small, whereas inversion provides exact results, particularly in case of shallow anomalous target; (2) crossover between in-phase and out-of-phase data could resulted from a small shallow conductive target or a large deep one; (3) selection of a reasonable environmental resistivity has an important impact on the inversion process; and (4) the numerical reflection resulted during VLF-EM data inversion could lead to an erroneous interpretation.

Relational Data Base Management Systems (RDBMS) are currently the most popular database management systems. The relational model is a simple and powerful model for representing real world applications. However, it lacks the expressiveness of conceptual models. Unlike the latter, the relational model does not offer the generalization abstraction. Therefore, it does not allow the designer to represent directly a large

This letter presents a new nonparametric approach, based on spline (SP) regression, for estimating the satellite altimeter sea-state bias (SSB) correction. Model evaluation is performed with models derived from a local linear kernel (LK) smoothing, the method which is currently used to build operational altimeter SSB models. The key reasons for introducing this alternative approach for the SSB application are simplicity in accurate model generation, ease in model replication among altimeter research teams, reduced computational requirements, and its suitability for higher dimensional SSB estimation. It is shown that the SP-and LK-based SSB solutions are effectively equivalent within the datadense portion, with an offset below 0.1 mm and a rms difference of 1.9 mm for the 2-D (wave height and wind speed) model. Small differences at the 1-5-mm level do exist in the case of low data density, particularly at low wind speed and high sea state. Overall, the SP model appears to more closely follow the bin-averaged SSB estimates.

AS CMOS FEATURE size scales downward, the interaction between design and process intensifies, resulting in strong layout-dependent proximity effects. These effects occur because a transistor's electrical properties depend on the context of its placement. 1-4 A MOSFET's channel length L and width W are no longer sufficient to determine its characteristics. Layout parameters such as polysilicon spacing, length of diffusion (LOD), and well boundary placement 5 become necessary to fully model device behavior. At 45 nm, the systematic variation between two transistors of the same L and W can reach more than 30% in drive current (I ON ) and as high as 100 mV in threshold voltage (V TH ). Such strong layout-dependent effects pose challenges to circuit design and demand fundamental changes in modeling and design methodologies.

An extensively revised heuristic-analytic theory of reasoning is presented incorporating three principles of hypothetical thinking. The theory assumes that reasoning and judgment are facilitated by the formation of epistemic mental models that are generated one at a time (singularity principle) by preconscious heuristic processes that contextualize problems in such a way as to maximize relevance to current goals (relevance principle). Analytic processes evaluate these models but tend to accept them unless there is good reason to reject them (satisficing principle). At a minimum, analytic processing of models is required so as to generate inferences or judgments relevant to the task instructions, but more active intervention may result in modification or replacement of default models generated by the heuristic system. Evidence for this theory is provided by a review of a wide range of literature on thinking and reasoning.

A mathematical model of population interactions between Varroa destructorand a honey bee colony is described. Validation tests indicate that the model generatesmite population predictions that are similar to those from actual colonies including: weekly mite-drop, daily rates of population increase, and exponential growth rates for mite populations. The modelpredicts that colony survival thresholds for mite populations and the effectiveness of miticides such as fluvalinate are dependent on climate and the yearly brood rearing cycle in a colony. Miticides applied in the late summerprovide the best chances for the sur vival ofheavily infested colonies. The model also predicts that large mite populations treated with miticides in the spring will recover by autumn to levels similarto those in untreatedcolonies. This is because in the treated colonies the surviving mites infest drone brood at lower numbers per cell and this increases repro ductive success and hence the growth rate of the mite population.

Software testing is one of the most widely used methods for quality assurance and fault detection purposes. However, it is one of the most expensive, tedious and time consuming activities in software development life cycle. Code-based and specification-based testing has been going on for almost four decades. Model-based testing (MBT) is a relatively new approach to software testing where the

The aim of this study is to examine the association between sense of community, walking, and neighborhood design characteristics. The current study is based on a sub-sample of participants (n ¼ 609) from the US Atlanta SMARTRAQ study who completed a telephone survey capturing physical activity patterns, neighborhood perceptions, and social interactions. Objective measures of neighborhood form were also computed. Univariate and multivariate models (General Linear Models (GLM)) were used to examine the association between sense of community (SofC) and aspects of the built environment, physical activity, and neighborhood perceptions. In multivariate models the impact on SofC was examined with progressive adjustment for demographics characteristics followed by walking behavior, neighborhood design features, neighborhood perceptions and time spent traveling in a car.

ABSTRACT The paper proposes the use of ultracapacitor storage device in order to support the mismatch between the available PV source power and microgrid load requirement. A realistic simulation scheme was implemented to evaluate the hybrid power system behaviour under varying microgrid load requirements. The operating performance were observed in steady state and transient conditions. The action of the ultracapacitor was pointed out, while the PV source operated at the maximum power point. Some discussions about the behaviour of the components and system operating characteristics were reported. The growing trend in both energy market deregulation and environmental preservation is forcing studies and applications of Distributed Generation (DG). DG, connected to local loads and distribution grids, is an extremely interesting issue. It offers the opportunity of constructing smart- and micro-grids, which are emerging as an integral feature of the future power systems. Microgrids are clusters of loads and micro sources operating as a single controllable power system. Microgrids can operate in parallel with the grid, as an autonomous power island, or in transition between grid- connected mode and islanded mode of operation. In the non-autonomous mode, the microgrid produces power while interconnected to the utility system. In the autonomous mode, the microgrid serves its electrical load without drawing power from the distribution utility. When possible, micro generation units are dispatched on the minimization of variable costs for service providing. So, real-time optimization in microgrids is performed through frequent adjustments of generator outputs to

J.D. Van Wees). 1 In this paper we define basin modeling, following conventions in E&P industry to be focussed on modeling of hydrocarbon maturation, migration and trapping in the sedimentary cover, and tectonic modeling to be focused on thermo-mechanical aspects of lithosphere deformation, driving basin (de)formation.

Finite element (FE) analysis of the effect of implant positioning on the performance of cementless total hip replacements (THRs) requires the generation of multiple meshes to account for positioning variability. This process can be labour intensive and time consuming as CAD operations are needed each time a specific orientation is to be analysed. In the present work, a mesh morphing technique is developed to automate the model generation process. The volume mesh of a baseline femur with the implant in a nominal position is deformed as the prosthesis location is varied. A virtual deformation field, obtained by solving a linear elasticity problem with appropriate boundary conditions, is applied. The effectiveness of the technique is evaluated using two metrics: the percentages of morphed elements exceeding an aspect ratio of 20 and an angle of 165 • between the adjacent edges of each tetrahedron. Results show that for 100 different implant positions, the first and second metrics never exceed 3% and 3.5%, respectively. To further validate the proposed technique, FE contact analyses are conducted using three selected morphed models to predict the strain distribution in the bone and the implant micromotion under joint and muscle loading. The entire bone strain distribution is well captured and both percentages of bone volume with strain exceeding 0.7% and bone average strains are accurately computed. The results generated from the morphed mesh models correlate well with those for models generated from scratch, increasing confidence in the methodology. This morphing technique forms an accurate and efficient basis for FE based implant orientation and stability analysis of cementless hip replacements.