bluuebunny/crossref_metadata_2025_split huggingface dataset:
Atlantic air–sea interaction and seasonal predictability
Authors: Rodwell M. J. , Folland C. K. 
Published: December 2006

AbstractWe analyse patterns of North Atlantic air–sea interaction in observations and model output throughout the annual cycle with the dual aims of validating natural variability in climate models, and quantifying seasonal predictability of the atmosphere and of ocean surface temperatures.The Met Office's HadCM3 coupled ocean–atmosphere model is shown to represent well the atmospheric forcing of sea surface temperature (SST) in the North Atlantic region through the action of latent‐heat fluxes. Winter ocean temperature anomalies in both observations and model appear to be preserved below the shallow summer mixed layer and to re‐emerge in the following autumn.We find observational evidence from the last half of the twentieth century for SST forcing of the atmospheric circulation in the North Atlantic region. Results validate our atmospheric model (HadAM2b) and confirm the levels of potential predictability of the North Atlantic Oscillation (NAO) that have been found in recent modelling studies. We suggest that the ultimate correlation skill of a winter NAO hindcast in this period is in the range 0.45 to 0.63.Analysis of observational and atmospheric model data from the first half of the twentieth century identifies very little predictability of the winter NAO. We suggest that the change in seasonal predictability is genuine and may be related to the strength of decadal oscillations.The ocean–atmosphere model, which incorporates a different atmospheric component (HadAM3), fails to show a causal link between North Atlantic temperatures and the atmospheric circulation even during periods where low‐frequency variability is as strong as in the recent observations.A brief observational investigation suggests that any implied predictability of the winter NAO based on a knowledge of South Atlantic SSTs depends on the existence of secular trends in the data. Tropical Pacific SSTs appear to influence the winter climate of the North Atlantic region, but not via trends in the NAO. © Crown copyright, 2002.
Study of hail density parametrizations
Authors: Castellano N. E. , Nasello O. B. , Levi L. 
Published: December 2006

AbstractOne aspect of hailstone growth that has received attention over the last twenty years is the importance of low‐density riming growth in hail. Density is an important parameter in riming growth because it regulates hail size and is also involved in other atmospheric processes, like crystal multiplication, charge transfer, etc. New numerical dynamic and cinematic models take into account the variability of density with growth parameters (such as size of cloud droplets, impact velocity and surface temperature) in order to attain more realistic results. These kinds of models need to have a function that describes the real low‐density riming process.Analysing previous results, it is clear that several different empirical parametrizations are employed to describe density. These parametrizations relate density to growth parameters through the variable X=Vob/Ts, where Vo is the impact velocity of droplets into the target, b is the droplet size, and Ts the hail surface temperature.These empirical expressions give different density values for identical growth conditions. It is important to note that these parametrizations stem from experimental data obtained in very different growth conditions and with different collector geometries.Working with experimental density data, we can show that different parametrizations are equivalent if X is defined in an appropriate way (taking into account correct impact velocity and collector geometry). Different environmental conditions are taken into account by means of Stokes' parameter.Due to this finding, we have aimed at developing a parametrization to be used in cloud models, which satisfactorily represents all experimental results. Copyright © 2002 Royal Meteorological Society
Linearized radiation and cloud schemes in the ECMWF model: Development and evaluation
Authors: Janiskov'a Marta , Mahfouf Jean‐françois , Morcrette Jean‐jacques , Chevallier Frederic 
Published: December 2006

AbstractA proper consideration of cloud–radiation interactions in linearized models is required for variational assimilation of cloud properties. Therefore, both a linearized cloud scheme and a linearized radiation scheme have been developed for the European Centre for Medium‐Range Weather Forecasts (ECMWF) data assimilation system. The tangent‐linear and adjoint versions of the ECMWF short‐wave radiation scheme are prepared without a priori modifications. The complexity of the radiation scheme for the long‐wave part of the spectrum makes accurate computations expensive. To reduce its computational cost, a combination of artificial neural networks and Jacobian matrices is defined for the linearized long‐wave radiation scheme. The linearized cloud scheme is diagnostic and has been adapted for this study. The accuracy of the linearization of both radiation and diagnostic cloud schemes is examined. The inclusion of a more sophisticated radiation scheme within the existing linearized parametrizations improves the accuracy of the tangent‐linear approximation. However, the impact of the linearized diagnostic cloud scheme is small, suggesting that the linearized model will require further developments of cloud parametrization.The adjoint technique is used to investigate the sensitivity of the radiation schemes to changes in temperature, humidity and cloud properties. This study shows which variables can be adjusted when certain observations of the surface and/or of the top‐of‐atmosphere radiation fluxes are used in data assimilation. It also indicates the vertical extent of the influence of such observations. Copyright © 2002 Royal Meteorological Society.
Near‐surface turbulent fluxes in stable stratification: Calculation techniques for use in general‐circulation models
Authors: Zilitinkevich S. S. , Perov V. L. , King J. C. 
Published: December 2006

AbstractPractically oriented flux‐calculation techniques based on correction functions to the neutral drag and heat/mass transfer coefficients are further developed. In the traditional formulation, the correction functions depend only on the bulk Richardson number. However, data from measurements of turbulent fluxes and mean profiles in stable stratification over different sites exhibit too strong variability in this type of dependencies. Indirect evidence from climate and weather prediction modelling also shows that the traditional flux‐calculation technique is not sufficiently advanced. It is conceivable that other mechanisms besides the surface‐layer stratification and, therefore, other arguments besides the bulk Richardson number must be considered. The proposed technique includes a newly discovered effect of the static stability in the free atmosphere on the surface‐layer scaling and accounts for the general essential difference between the roughness lengths for momentum and scalars. Besides bulk Richardson number, recommended correction functions depend on one more stability parameter, involving the Brunt–Väisälä frequency in the free atmosphere, and on the roughness lengths. Copyright © 2002 Royal Meteorological Society.
Potential improvement to forecasts of two severe storms using targeted observations
Authors: Leutbecher M. , Barkmeijer J. , Palmer T. N. , Thorpe A. J. 
Published: December 2006

AbstractThe potential to improve short‐range forecasts of two extratropical storms by using supplementary observations in regions lacking accurate observations is investigated. In the idealized framework used here, a control and a truth experiment are selected from a set of forecasts initialized with analyses from different numerical weatherprediction centres. Synthetic soundings of wind and temperature are created from the truth experiment and are assimilated with four‐dimensional variational analysis using the operational observation‐error estimates for radiosondes and the initial condition of the control experiment as background. Through multiple analysis/forecast experiments we obtain a nonlinear estimate of the optimal zone for observing (OZO); that is the zone in which the use of a given number of supplementary observations leads to the largest reduction in forecast error. We evaluate targeting techniques based on either total‐energy singular vectors (TESVs) or on Hessian singular vectors (HSVs) by comparison with the OZO and by comparison with experiments in which the same amount of supplementary observations are distributed in an untargeted manner, namely with a random distribution scheme (RDS).Overall, the HSV targeting is superior to the TESV targeting in the two cases. In one case there is a significant difference between the target regions determined with TESVs and HSVs. The HSV‐based observing strategy resembles the OZO in terms of the observing region and the achieved forecast‐error reduction. With the RDS, the forecast error is variable and likely to be larger than the forecast error obtained with singular‐vector targeting. Experiments with target regions of different sizes show that supplementary observations in an area of about 3×106 km2 are required to achieve a significant forecast improvement. A two‐dimensional sampling pattern with soundings spaced at a distance of about 1–2 times the horizontal correlation length‐scale of the backgrounderror estimate appears very efficient. In additional impact experiments for one case, observations were perturbed with noise to represent observational error. The perturbations are almost as likely to improve the forecast as to worsen it compared with the forecast using unperturbed observations. Copyright © 2002 Royal Meteorological Society.
Variational assimilation of ocean tomographic data: Twin experiments in a quasi‐geostrophic model
Authors: Rémy Elisabeth , Gaillard Fabienne , Verron Jacques 
Published: December 2006

AbstractThe possibility of using tomography data as a constraint in variational data assimilation is explored by performing twin experiments. Realistic travel‐time data are generated in a quasi‐geostrophic model applied to the western Mediterranean Sea. After checking the robustness of the method with this dataset, a sensitivity study analyses the propagation of information by the model, and tests the effect of different parameters such as the starting point of the optimization or the length of the assimilation period. It appears that the variational method is well adapted to the nature of tomographic data that provide at the same time high time resolution and space integrals. The results clearly show the ability of this dataset to recover the temporal evolution of heat content in each layer and improve various components of the circulation described by the model. Tomography must then be considered as an important source of information that may contribute with altimetry or local in situ measurement to the description of the ocean state and its evolution. Copyright © 2002 Royal Meteorological Society.
The counter‐propagating Rossby‐wave perspective on baroclinic instability. I: Mathematical basis
Authors: Heifetz E. , Bishop C. H. , Hoskins B. J. , Methven J. 
Published: December 2006

AbstractIt is shown that Bretherton's view of baroclinic instability as the interaction of two counter‐propagating Rossby waves (CRWs) can be extended to a general zonal flow and to a general dynamical system based on material conservation of potential vorticity (PV). The two CRWs have zero tilt with both altitude and latitude and are constructed from a pair of growing and decaying normal modes. One CRW has generally large amplitude in regions of positive meridional PV gradient and propagates westwards relative to the flow in such regions. Conversely, the other CRW has large amplitude in regions of negative PV gradient and propagates eastward relative to the zonal flow there. Two methods of construction are described. In the first, more heuristic, method a ‘home‐base’ is chosen for each CRW and the other CRW is defined to have zero PV there. Consideration of the PV equation at the two home‐bases gives ‘CRW equations’ quantifying the evolution of the amplitudes and phases of both CRWs. They involve only three coefficients describing the mutual interaction of the waves and their self‐propagation speeds. These coefficients relate to PV anomalies formed by meridional fluid displacements and the wind induced by these anomalies at the home‐bases. In the second method, the CRWs are defined by orthogonality constraints with respect to wave activity and energy growth, avoiding the subjective choice of home‐bases. Using these constraints, the same form of CRW equations are obtained from global integrals of the PV equation, but the three coefficients are global integrals that are not so readily described by ‘PV‐thinking’ arguments. Each CRW could not continue to exist alone, but together they can describe the time development of any flow whose initial conditions can be described by the pair of growing and decaying normal modes, including the possibility of a super‐modal growth rate for a short period. A phase‐locking configuration (and normal‐mode growth) is possible only if the PV gradient takes opposite signs and the mean zonal wind and the PV gradient are positively correlated in the two distinct regions where the wave activity of each CRW is concentrated. These are easily interpreted local versions of the integral conditions for instability given by Charney and Stern and by Fjørtoft. Copyright © 2004 Royal Meteorological Society
T‐Cell epitope discovery for variola and vaccinia viruses
Authors: Kennedy Richard , Poland Gregory A. 
Published: December 2006

AbstractVariola major, the causative agent of smallpox, afflicted mankind throughout history until the worldwide World Health Organisation WHO vaccination campaign successfully eradicated the disease. Unfortunately, recent concerns about bioterrorism have renewed scientific interest in this virus. One essential component of our biodefense and preparedness efforts is an understanding of poxvirus immunity. To this end a number of laboratories have sought to discover T‐ and B‐Cell epitopes from select agents such as variola virus. This review focuses on the efforts to identify CD8+ T‐Cell epitopes from poxviruses as a means to develop new vaccines and therapeutics. A wide variety of techniques have been employed by several research groups to provide complementary information regarding cellular immune responses to poxviruses. In the last several years well over 100 T‐Cell epitopes have been identified and the work rapidly continues. The information gleaned from these studies will not only give us a greater understanding of immunity to variola virus and other viruses, but also provide a foundation for next generation vaccines and additional tools with which to study host‐pathogen interactions. Copyright © 2006 John Wiley & Sons, Ltd.
Software reliability evaluation in service operation
Authors: Miyakawa Osamu , Tohma Yoshihiro 
Published: December 2006

AbstractThere have been studies of the software reliability growth model based on the hypergeometric distribution model, most of which have been concerned with the testing and debugging process. In this paper, the assumption of a hypergeometric distribution model for software reliability evaluation in service operation is reviewed, and the estimation power of the model is investigated by using actual fault data. It is found that the estimated mean time between failures agrees with the observed value. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 38(1): 97–104, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10279
A factorial representation of permutations and its application to flow‐shop scheduling
Authors: Watase Kazunori 
Published: December 2006

AbstractThe first objective of the current research was to incorporate the NEH search method, which is the classical heuristic algorithm for the flow‐shop scheduling problem, into a genetic algorithm to improve search performance. To achieve this objective, the author used factorial numbers to represent permutations. Since chromosome representations according to factorial numbers have a one‐to‐one correspondence with permutations, there is no redundancy. Since no lethal gene is produced by crossover, uniform crossover can also be applied, not just one‐point or two‐point crossover. In addition, it was apparent that the NEH concept could be naturally introduced into the genetic algorithm search process by arranging n jobs in ascending order of total work times as the basic permutation that is used when associating permutations and factorial numbers. Factorial numbers can also be used to represent certain types of constraints. The second objective of the current research was to verify the effectiveness of the factorial number representation in order‐constrained permutation searches. To accomplish this, the author performed numerical experiments and obtained superior results than were obtained by conventional methods. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 38(1): 73–86, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10348
An F0contour control model using an F0contour codebook
Authors: Kagoshima Takehiko , Morita Masahiro , Seto Shigenobu , Akamine Masami , Shiga Yoshinori 
Published: December 2006

AbstractIn this paper the authors propose a fundamental frequency (F0) control model using a representative vector and then propose a method to train the control rules for the model parameters using a speech database. The representative vector is a vector which represents the typical F0contour for accent phrases, and a set of representative vectors is referred to as a representative vector codebook. The authors generated F0contour for sentences by performing linear expansion or contraction by mora in line with the length of the phoneme duration and the parallel shift (offset) on the logarithmic frequency axis and then concatenating them for representative vectors selected for each accent phrase. Training the control rules corresponds to extracting from the speech database the representative vector codebook, the representative vector selection rules, and the offset prediction rules. Based on the criterion that the error between the F0contour for the speech database and the contour generated by the model (the approximation error) be minimized, the control rules were trained. The results of training experiments for the control rules using a speech database consisting of four female speakers showed that an F0contour close to the original speaker can be generated even for sentences not included in the training data. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 38(1): 62–72, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10386
Simultaneous training of fuzziness generator and inference rules in the freehand curve identifier FSCI
Authors: Oguma Motoaki , Takikawa Hiroyasu , Saga Sato 
Published: December 2006

AbstractFreehand curve recognition method FSCI is already proposed and consists of the following procedure. The freehand drawing is represented as a fuzzy curve model by using a fuzziness generator, and fuzzy inference is used to find as simple a geometrical curve as possible, so that the drawing intention of the user is identified. It is recognized that the adequacy of the parameter setting in the fuzziness generator and the inference rules has a serious effect on the identification performance of FSCI. Thus, training optimization for the fuzziness generator using the genetic algorithm, and training optimization of inference rules using a neural network have been separately proposed. This paper proposes a new method which achieves simultaneous training optimization of the fuzziness generator and the inference rules using a neural network. The effectiveness of the method is demonstrated experimentally. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 38(1): 51– 61, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10387.
Interaction of neuronal I/O functions with STDP
Authors: Urakubo Hidetoshi , Watanabe Masataka , Kondo Shunsuke 
Published: December 2006

AbstractSpike timing‐dependent synaptic plasticity (STDP) develops neural circuits through close interaction with the firing function of single neurons. Here, we investigate the neuronal firing function dependency of STDP about a single‐compartment Hodgkin–Huxley (HH) model neuron and a leaky integrate‐and‐fire (LIF) model neuron. Computer simulation shows that the development of synaptic strength by synaptic input pairs with constant intervals depends on the firing function of the models. The more organized packet inputs also develop synaptic strength in a firing function‐dependent manner, to realize specific information processing. These results suggest that in real biological systems too, STDP with the same time window will develop different neural circuits, depending on the neuronal firing functions. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 38(1): 41–50, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20234
A QA cycle for teaching programming. A mechanism for automatically posing questions corresponding to learner's skill
Authors: Nakajima Hideki , Takahashi Naohisa , Hosokawa Yoshihide 
Published: December 2006

AbstractThis paper proposes a QA cycle execution system for programming education matched to the learner's skill. The proposed system has the following features. (1) The language describing the QA cycle (EDML: Exercise Design Markup Language) is created. EDML is a language with the following functions. Various questions with the same difficulty and different content can be automatically generated. The answer evaluation environment and the selection of questions matched to the skill are described in a unified text for iterative learning matched to the learner's skill. (2) A method is established in which a learning system can easily be constructed by using an existing mail system. With the proposed approach, a remote learning system can be created without implementing functions for network security, generation of temporary logs, or program buffering in case of overload, which are essential elements of a remote learning system. This paper also describes the construction of a prototype of the proposed system. The proposed system was applied to a Pascal programming course for college freshman, and the results are described herein. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 38(1): 28–40, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20471
Research on an information processing system for shakuhachi tablatures
Authors: Noguchi Masato , Simura Satosi , Tsuboi Kuniharu , Matsushima Toshiaki 
Published: December 2006

AbstractThe development of an information processing system for traditional music is very much behind the times. In order to improve this situation, we have researched a system for shakuhachi scores. It is a multimedia system equipped with various functions needed for processing a shakuhachi score, such as handwritten editing, mutual conversion among various schools, and playback with a presentation of the performance method. Furthermore, a method for data expression of a shakuhachi score was newly devised. By using this system, it is possible to create a shakuhachi score effectively and it is also expected that it can be used as a beginner's shakuhachi self‐study tool. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 38(1): 18–27, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20553