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Complex Problems (complex + problem)
Selected AbstractsA Complex Problem of Diastereoisomerism: Synthesis and Stereochemistry of 1,4-Bis-{r-1-aza-c-5-ethyl-3,7-dioxabicyclo [3.3.0]octane-c-2-yl}-benzene (III).CHEMINFORM, Issue 15 2005Carmen Maiereanu No abstract is available for this article. [source] Automatic Light Source Placement for Maximum Visual Information RecoveryCOMPUTER GRAPHICS FORUM, Issue 2 2007P.-P. Vázquez Abstract The automatic selection of good viewing parameters is a very complex problem. In most cases, the notion of good strongly depends on the concrete application. Moreover, when an intuitive definition of good view is available, it is often difficult to establish a measure that brings it to the practice. Commonly, two kinds of viewing parameters must be set: camera parameters (position and orientation) and lighting parameters (number of light sources, its position and eventually the orientation of the spot). The first parameters will determine how much of the geometry can be captured and the latter will influence on how much of it is revealed (i.e., illuminated) to the user. Unfortunately, ensuring that certain parts of a scene are lit does not make sure that the details will be communicated to the user, as the amount of illumination might be too small or too high. In this paper we define a metric to calculate the amount of information relative to an object that is effectively communicated to the user given a fixed camera position. This measure is based on an information-based concept, the Shannon entropy, and will be applied to the problem of automatic selection of light positions in order to adequately illuminate an object. In order to validate the results, we have carried out an experiment on users, this experiment helped us to explore other related measures. [source] The behaviour of soil process models of ammonia volatilization at contrasting spatial scalesEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 6 2008R. Corstanje Summary Process models are commonly used in soil science to obtain predictions at a spatial scale that is different from the scale at which the model was developed, or the scale at which information on model inputs is available. When this happens, the model and its inputs require aggregation or disaggregation to the application scale, and this is a complex problem. Furthermore, the validity of the aggregated model predictions depends on whether the model describes the key processes that determine the process outcome at the target scale. Different models may therefore be required at different spatial scales. In this paper we develop a diagnostic framework which allows us to judge whether a model is appropriate for use at one or more spatial scales both with respect to the prediction of variations at those scale and in the requirement for disaggregation of the inputs. We show that spatially nested analysis of the covariance of predictions with measured process outcomes is an efficient way to do this. This is applied to models of the processes that lead to ammonia volatilization from soil after the application of urea. We identify the component correlations at different scales of a nested scheme as the diagnostic with which to evaluate model behaviour. These correlations show how well the model emulates components of spatial variation of the target process at the scales of the sampling scheme. Aggregate correlations were identified as the most pertinent to evaluate models for prediction at particular scales since they measure how well aggregated predictions at some scale correlate with aggregated values of the measured outcome. There are two circumstances under which models are used to make predictions. In the first case only the model is used to predict, and the most useful diagnostic is the concordance aggregate correlation. In the second case model predictions are assimilated with observations which should correct bias in the prediction, and errors in the variance; the aggregate correlations would be the most suitable diagnostic. [source] A fuzzy analytic hierarchy process approach in modular product designEXPERT SYSTEMS, Issue 1 2001W.B Lee Product development stages. The analytic hierarchy process (AHP), which breaks down a complex problem into simple hierarchical decision-making processes, can be incorporated with fuzzy logic to suggest the relative strength of the factors in the corresponding criteria, thereby enabling the construction of a fuzzy judgement matrix to facilitate decision-making. This paper proposes a fuzzy AHP approach in modular product design complemented with a case example to validate its feasibility in a real company. Test findings indicate that the approach is helpful for providing key decision support information in terms of product module selection during product development stages. The significance of the contribution of this paper is the suggestion of a novel approach in modular product design, embracing a combination of computational intelligence and traditional techniques, thereby providing more alternatives and ideas for those researchers who are interested in this field of study. [source] Theoretical crack path predictionFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 1-2 2005H. A. RICHARD ABSTRACT In many practical cases, the crack growth leads to abrupt failure of components and structures. For reasons of a reliable quantification of the endangerment due to sudden fracture of a component, therefore, it is of enormous importance to know the threshold values, the crack paths and the growth rates for the fatigue crack growth as well as the limiting values for the beginning of unstable crack growth (fracture toughness). This contribution deals with the complex problem of a,however initiated,crack, that is subjected to a mixed-mode loading. It will present the hypotheses and concepts, which describe the superposition of Mode I and Mode II (plane mixed mode) as well as the superposition of all three modes (Mode I, II and III) for spatial loading conditions. Those concepts admit a quantitative appraisal of such crack situations and a characterization of possible crack paths. [source] An operator-split ALE model for large deformation analysis of geomaterialsINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 12 2007Y. Di Abstract Analysis of large deformation of geomaterials subjected to time-varying load poses a very difficult problem for the geotechnical profession. Conventional finite element schemes using the updated Lagrangian formulation may suffer from serious numerical difficulties when the deformation of geomaterials is significantly large such that the discretized elements are severely distorted. In this paper, an operator-split arbitrary Lagrangian,Eulerian (ALE) finite element model is proposed for large deformation analysis of a soil mass subjected to either static or dynamic loading, where the soil is modelled as a saturated porous material with solid,fluid coupling and strong material non-linearity. Each time step of the operator-split ALE algorithm consists of a Lagrangian step and an Eulerian step. In the Lagrangian step, the equilibrium equation and continuity equation of the saturated soil are solved by the updated Lagrangian method. In the Eulerian step, mesh smoothing is performed for the deformed body and the state variables obtained in the updated Lagrangian step are then transferred to the new mesh system. The accuracy and efficiency of the proposed ALE method are verified by comparison of its results with the results produced by an analytical solution for one-dimensional finite elastic consolidation of a soil column and with the results from the small strain finite element analysis and the updated Lagrangian analysis. Its performance is further illustrated by simulation of a complex problem involving the transient response of an embankment subjected to earthquake loading. Copyright © 2007 John Wiley & Sons, Ltd. [source] FOIST: Fluid,object interaction subcomputation techniqueINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 9 2009V. Udoewa Abstract Our target is to develop computational techniques for studying aerodynamic interactions between multiple objects. The computational challenge is to predict the dynamic behavior and path of the object, so that separation (the process of objects relatively falling or moving away from each other) is safe and effective. This is a very complex problem because it has an unsteady, 3D nature and requires the solution of complex equations that govern the fluid dynamics (FD) of the object and the aircraft together, with their relative positions changing in time. Large-scale 3D FD simulations require a high computational cost. Not only must one solve the time-dependent Navier,Stokes equations governing the fluid flow, but also one must handle the equations of motion of the object as well as the treatment of the moving domain usually treated as a type of pseudo-solid. These costs include mesh update methods, distortion-limiting techniques, and remeshing and projection tactics. To save computational costs, point force calculations have been performed in the past. This paper presents a hybrid between full mesh-moving simulations and the point force calculation. This mesh-moving alternative is called FOIST: fluid,object subcomputation interaction technique. Copyright © 2009 John Wiley & Sons, Ltd. [source] A simple finite element model for vibration analyses induced by moving vehiclesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 12 2006Shen-Haw Ju Abstract This study developed a simple finite element method combining the moving wheel element, spring,damper element, lumped mass and rigid link effect to simulate complicated vehicles. The advantages of this vehicle model are (1) the dynamic matrix equation is symmetric, (2) the theory and formulations are very simple and can be added to a standard dynamic finite element codes easily and (3) very complicated vehicle models can be assembled using the proposed elements as simple as the traditional finite element method. The Fryba's solution of a simply supported beam subjected to a moving two-axle system was analysed to validate this finite element model. For a number of numerical simulations, the two solutions are almost identical, which means that the proposed finite element model of moving vehicles is considerably accurate. Field measurements were also used to validate this vehicle model through a very complicated finite element analysis, which indicates that the current moving vehicle model can be used to simulate complex problem with acceptable accuracy. Copyright © 2006 John Wiley & Sons, Ltd. [source] Hybrid adaptive predictive control for a dynamic pickup and delivery problem including traffic congestionINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 2 2008Cristián E. Cortés Abstract This paper presents a hybrid adaptive predictive control approach to incorporate future information regarding unknown demand and expected traffic conditions, in the context of a dynamic pickup and delivery problem with fixed fleet size. As the routing problem is dynamic, several stochastic effects have to be considered within the analytical expression of the dispatcher assignment decision objective function. This paper is focused on two issues: one is the extra cost associated with potential rerouting arising from unknown requests in the future, and the other is the potential uncertainty in travel time coming from non-recurrent traffic congestion from unexpected incidents. These effects are incorporated explicitly in the objective function of the hybrid predictive controller. In fact, the proposed predictive control strategy is based on a multivariable model that includes both discrete/integer and continuous variables. The vehicle load and the sequence of stops correspond to the discrete/integer variable, adding the vehicle position as an indicator of the traffic congestion conditions. The strategy is analyzed under two scenarios. The first one considers a predictable congestion obtained using historical data (off-line method) requiring a predictive model of velocities distributed over zones. The second scenario that accepts unpredictable congestion events generates a more complex problem that is managed by using both fault detection and isolation and fuzzy fault-tolerant control approaches. Results validating these approaches are presented through a simulated numerical example. Copyright © 2007 John Wiley & Sons, Ltd. [source] Enhancing Delphi research: methods and resultsJOURNAL OF ADVANCED NURSING, Issue 5 2004Holly Powell Kennedy PhD CNM FACNM Background., The Delphi method provides an opportunity for experts (panelists) to communicate their opinions and knowledge anonymously about a complex problem, to see how their evaluation of the issue aligns with others, and to change their opinions, if desired, after reconsideration of the findings of the group's work. Delphi studies have the potential to provide valuable information, yet few researchers have taken further steps to support or refine their findings. Without this step there is a potential threat to the applicability, or external validity, of the results. Aims., The purpose of this article is to present an argument for further inquiry to enhance and support Delphi findings, and specific approaches to this will be considered. Methods., Methods to enhance, expand, or refine Delphi study findings are described. Mixed method design within a Delphi study on midwifery practice is described, and a follow-up narrative study to examine the findings is presented. Findings., Selected results from the follow up narrative study are presented to convey how the narrative data clarified the Delphi findings. Together, the studies provide a more robust depiction of midwifery practice, process, and outcomes. Although there were similarities to the dimensions identified previously, there was a more dynamic focus and explanation of the interaction between the midwife, the woman who had received midwifery care, and the health care system. Study limitations., Lack of diversity in the sample and the midwives' familiarity with the author's past research represent a potential threat to the findings. Prolonged interviews and multiple narratives were gathered in an effort to control for this. Conclusion., Delphi studies are research exercises conducted by a panel of experts. Designing studies to further enhance, clarify, or refine their findings from the context of practice holds promise for their ability to influence clinical care. [source] Integrating Message Effects and Behavior Change Theories: Organizing Comments and Unanswered QuestionsJOURNAL OF COMMUNICATION, Issue 2006Joseph N. Cappella Three broad classes of theories about message effects in cancer control are presented in this special supplement to the Journal of Communication. These are behavior change, information processing, and message effects theories. All three types have implications for the design of messages for cancer control. The theories are not just different approaches to a complex problem but offer complementary perspectives on the effects of messages on audiences. This summary article explores why theory is so important to efficient research in message effects and speculates about the interrelation among behavior change, information processing, and message effects models. [source] Modeling of turbulent precipitation: A transported population balance-PDF methodAICHE JOURNAL, Issue 4 2010Giovanni di Veroli Abstract Turbulent precipitation is a complex problem, whose mathematical description of precipitation requires a coupling of fluid dynamics with the population balance equation (PBE). In the case of turbulent flow, this coupling results in unclosed equations due to the nonlinear nature of precipitation kinetics. In this article, we present a methodology for modeling turbulent precipitation using the concept of the transported probability density function (PDF) in conjunction with a discretized PBE, simulated via a Lagrangian stochastic method. The transported PBE-PDF approach resolves the closure problem of turbulent precipitation for arbitrarily complex precipitation kinetics, while retrieving the full particle size distribution (PSD). The method is applied to the precipitation of BaSO4 in a turbulent pipe flow and comparisons are made with the experimental results of Baldyga and Orciuch (Chem Eng Sci. 2001;56:2435-2444) showing excellent agreement, while insight is drawn into the mechanisms that determine the evolution of the product PSD. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Evolution and homology of the astragalus in early amniotes: New fossils, new perspectivesJOURNAL OF MORPHOLOGY, Issue 4 2006F. Robin O'Keefe Abstract The reorganization of the ankle in basal amniotes has long been considered a key innovation allowing the evolution of more terrestrial and cursorial behavior. Understanding how this key innovation arose is a complex problem that largely concerns the homologizing of the amniote astragalus with the various ossifications in the anamniote tarsus. Over the last century, several hypotheses have been advanced homologizing the amniote astragalus with the many ossifications in the ankle of amphibian-grade tetrapods. There is an emerging consensus that the amniote astragalus is a complex structure emerging via the co-ossification of several originally separate elements, but the identities of these elements remain unclear. Here we present new fossil evidence bearing on this contentious question. A poorly ossified, juvenile astragalus of the large captorhinid Moradisaurus grandis shows clear evidence of four ossification centers, rather than of three centers or one center as posited in previous models of astragalus homology. Comparative material of the captorhinid Captorhinikos chozaensis is also interpretable as demonstrating four ossification centers. A new, four-center model for the homology of the amniote astragalus is advanced, and is discussed in the context of the phylogeny of the Captorhinidae in an attempt to identify the developmental transitions responsible for the observed pattern of ossification within this clade. Lastly, the broader implications for amniote phylogeny are discussed, concluding that the neomorphic pattern of astragalus ossification seen in all extant reptiles (including turtles) arose within the clade Diapsida. J. Morphol. © 2006 Wiley-Liss, Inc. [source] Paracetamol use in musculoskeletal pain: an audit of use and patient perceptions of paracetamol as an effective analgesicMUSCULOSKELETAL CARE, Issue 4 2005Emma J Boger RGN BSc(Hons) DipHE Nurse Researcher Abstract Musculoskeletal pain is a complex problem with often very detrimental consequences which affects a high proportion of the general population. Health care professionals, when prescribing for musculoskeletal pain, often overlook simple analgesia. Patient perceptions of analgesia may vary to those of health care professionals, and in part affect the use of simple analgesia for musculoskeletal pain. This paper describes an audit of paracetamol use and patient perceptions of paracetamol as an effective analgesic agent, in 113 patients attending a musculoskeletal pain outpatient clinic in a university teaching hospital. The audit has helped prompt the development of a multi-disciplinary strategy to achieve optimum management. Copyright © 2005 John Wiley & Sons, Ltd. [source] A note on the complex semi-definite matrix Procrustes problemNUMERICAL LINEAR ALGEBRA WITH APPLICATIONS, Issue 6 2007J. Kiskiras Abstract This note outlines an algorithm for solving the complex ,matrix Procrustes problem'. This is a least-squares approximation over the cone of positive semi-definite Hermitian matrices, which has a number of applications in the areas of Optimization, Signal Processing and Control. The work generalizes the method of Allwright (SIAM J. Control Optim. 1988; 26(3):537,556), who obtained a numerical solution to the real-valued version of the problem. It is shown that, subject to an appropriate rank assumption, the complex problem can be formulated in a real setting using a matrix-dilation technique, for which the method of Allwright is applicable. However, this transformation results in an over-parametrization of the problem and, therefore, convergence to the optimal solution is slow. Here, an alternative algorithm is developed for solving the complex problem, which exploits fully the special structure of the dilated matrix. The advantages of the modified algorithm are demonstrated via a numerical example. Copyright © 2007 John Wiley & Sons, Ltd. [source] Health education for nurses in Japan to combat child abuseNURSING & HEALTH SCIENCES, Issue 3 2003Beverly M. Henry phd, hondsc Abstract A health education program for nurses was conducted to address the complex problem of child abuse, which has reached epidemic proportions. In Japan, the number of consultations has risen 23-fold over the past 11 years. Maltreatment of children is a public health problem as perilous as any contagious disease. The International Council of Nurses asks for nurses' leadership to strengthen measures to combat abuse throughout the world. The Japanese Nursing Association has published statements for prevention, detection and support. Yet, few community-based education programs with a multidisciplinary perspective have been reported that focus on nurses, the largest group of health providers. More than 200 nurse educators, clinicians and managers met for a one-day program designed to improve understanding of the nurses' role in combating the abuse and neglect of children and to formulate action plans. This significant health problem is addressed in the context of a health education program's needs, objectives, content and evaluation. [source] Male mating tactics in spider monkeys: sneaking to competeAMERICAN JOURNAL OF PRIMATOLOGY, Issue 9 2010K. Nicole Gibson Abstract I investigated the mating system and male mating tactics for a population of wild spider monkeys (Ateles belzebuth chamek), to identify the behaviors males used to achieve and maintain access to sexually receptive females, and to examine if some males used more tactics than other males and/or had differential access to females. Results show that the mating system mostly involved scramble competition polygyny and that males used a range of mating tactics and behaviors, previously unreported for spider monkeys. The most unusual feature of spider monkey mating behavior was the secretive nature of copulations,nearly all copulations were clandestine, but a few were in the presence of other group members. Fifteen sexually mature males were observed to copulate 43 times. These data provide the first opportunity to evaluate how female availability influences male,male competition. First, the operational sex ratio was highly skewed toward males because usually only one female was receptive in each community per month. Second, females only mated with a few males in their community in any one mating period, but some females mated over the course of multiple consecutive mating periods, eventually mating with most or all of the males in their community. Across all communities, 9 (21%) of the 43 copulations involved a single male,female partner, 20 (47%) involved four males mating with the same female, and males mated with from one to four different females. Fourteen of the 16 total adult males and 1 subadult male (10 total) copulated. One or two males in each community were successful in monopolizing access to receptive females, and these males did not usually have the highest rates of copulation. In this system, clandestine copulations are one behavioral solution to the complex problem of gaining mating exclusivity and, probably, exercising mate choice. Am. J. Primatol. 72:794,804, 2010. © 2010 Wiley-Liss, Inc. [source] Challenges and Strategies Related to Hearing Loss Among Dairy FarmersTHE JOURNAL OF RURAL HEALTH, Issue 4 2005Louise Hass-Slavin MSc ABSTRACT: Context: Farming is often imagined to be a serene and idyllic business based on historical images of a man, a horse, and a plow. However, machinery and equipment on farms, such as older tractors, grain dryers, and vacuum pumps, can have noise levels, which may be dangerous to hearing with prolonged, unprotected exposure. Purpose: This qualitative study in Ontario, Canada, explored the challenges and coping strategies experienced by dairy farmers with self-reported hearing loss and communication difficulties. Through in-depth interviews, 13 farmers who experience significant hearing loss were questioned about the challenges they face as a result of hearing loss and the strategies they use to overcome or compensate for problems. Findings: The 2 major challenges encountered by dairy farmers with a hearing loss were: (1) obtaining information from individuals, within groups, and through electronic media; and (2) working with animals, machinery, and noise. To cope with these challenges, participants used strategies identified as problem and emotion focused. Conclusions: Four themes arose from analysis of the challenges encountered and strategies used: 1Hearing loss is experienced as a "familiar," but "private," problem for dairy farmers. 2Communication difficulties can negatively affect the quality of relationships on the farm. 3Safety and risk management are issues when farming with a hearing loss. 4The management or control of excessive noise is a complex problem, because there are no completely reliable yet practical solutions. [source] Fixing reinforced tracheal tubes...a surprisingly complex problemANAESTHESIA, Issue 10 2008R. M. Beringer No abstract is available for this article. [source] Influence of proficiency level and constraints on viewpoint switching: a study in web designAPPLIED COGNITIVE PSYCHOLOGY, Issue 1 2009Aline Chevalier Web design is a complex problem in which designers have to consider the user's and the client's viewpoints to make satisfactory websites. Designers, particularly proficient ones, tend to privilege to the client's viewpoint to the detriment of the users' one. Consequently, websites often contain many usability violations and do not fit users' cognitive capacities, hence hampering navigation. The usability quality of websites may be proportional to designers' ability to switch between the client's and the user's viewpoints, which in turn may be influenced by designers' proficiency level. To explore the role of viewpoint switching in web design, performance was compared across three conditions emphasizing either the client's viewpoint, that of the user, or none of them in order to promote or hamper viewpoint switching. This manipulation had a significant effect on proficient designers' performance. Moreover, a significant relation between viewpoint switching and the usability quality of e-mock-ups was found. Copyright © 2008 John Wiley & Sons, Ltd. [source] HISTORY ILLUMINATED: WILLIAM HOLMAN HUNT'S LONDON BRIDGEART HISTORY, Issue 5 2006NANCY ROSE MARSHALL Grappling with the complex problem of how to represent history through the experience of ordinary people, William Holman Hunt's London Bridge of 1864 combined a modern urban crowd scene, a careful choice of depicted location, and an unusual deployment of light effects to create a painting about Victorian perceptions of time itself. By portraying a night-time scene lit by the gas illuminations on the bridge in honour of the wedding of the Prince and Princess of Wales, Hunt drew on the traditional aesthetic of the sublime to create a spectacle of an historic event , a royal marriage , that inspired both wonder and fear. Juxtaposing the flame-lit city with the moonlit Thames at the charged site of London Bridge allowed the artist to set in play the common Victorian framework one might term the ,moralizing sublime'. This pervasive mode of thought involved reading the mighty strivings of man and the modern industrial city as puny, transitory glimmers in comparison with the infinite onward rush of time; paradoxically, it also permitted the wilful overlooking of any negative yet ephemeral consequences of modernity. These ideas were underscored by the original exhibition of London Bridge with another work by Hunt in which light plays a key role in producing meaning: The Afterglow in Egypt. [source] Mapping solutions to obesity: lessons from the Human Genome ProjectAUSTRALIAN AND NEW ZEALAND JOURNAL OF PUBLIC HEALTH, Issue 6 2008Catriona M. F. Bonfiglioli Abstract Objective: To discuss appropriate endpoints for research designed to prevent obesity. Research investigating practical solutions to the complex multi-factorial global obesity epidemic may be stalled by undue emphasis on reduced body weight as the only acceptable endpoint. Approach: Considering prevention research in cardiovascular disease and tobacco control, we contend that investigations of intermediate endpoints make an important contribution to the multi-faceted approach needed to combat the complex problem of obesity. Conclusion: Intermediate endpoints are respected in other public health areas: reductions in risk factors such as high blood cholesterol or smoking are acceptable study endpoints for research aimed at reducing heart disease or lung cancer. Likewise, practical endpoints can be valuable in studies investigating interventions to reduce identified and potential intermediate risk factors for obesity, such as soft drink consumption. Implications: Reduced obesity is the global aim but obesity is not caused by one exposure and will not be solved by a single modality intervention. A wider debate about endpoint selection may assist research which identifies individual building blocks of obesity prevention in the same way as individual gene mapping contributed to the Human Genome Project. [source] Drug interactions in dermatological practiceCLINICAL & EXPERIMENTAL DERMATOLOGY, Issue 5 2008H. L. Tey Summary Systemic drugs are increasingly used in the treatment of dermatological diseases. Due to the high prevalence of polypharmacy, dermatologists are increasingly faced with the complex problem of drug interaction. Unlike adverse drug reactions, which are often unpredictable, drug interactions can be avoided. This article presents the significant drug interactions that are encountered in clinical practice, with the interactions categorized into those involving antimicrobials, immunosuppressants, antimalarials and colchicine, retinoids and psychiatric medications. There are few commonly used drugs that often cause drug interactions. These include ciclosporin, azole antifungal drugs, erythromycin, sulfonamides and rifampicin, and dermatologists should be alert whenever encountering them. A section on interactions of drugs with health supplements, herbs and food is also included, in view of the increasing use of alternative and complementary therapies in many parts of the world. [source] Grid services for earthquake scienceCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 6-7 2002Geoffrey Fox Abstract We describe an information system architecture for the ACES (Asia,Pacific Cooperation for Earthquake Simulation) community. It addresses several key features of the field,simulations at multiple scales that need to be coupled together; real-time and archival observational data, which needs to be analyzed for patterns and linked to the simulations; a variety of important algorithms including partial differential equation solvers, particle dynamics, signal processing and data analysis; a natural three-dimensional space (plus time) setting for both visualization and observations; the linkage of field to real-time events both as an aid to crisis management and to scientific discovery. We also address the need to support education and research for a field whose computational sophistication is rapidly increasing and spans a broad range. The information system assumes that all significant data is defined by an XML layer which could be virtual, but whose existence ensures that all data is object-based and can be accessed and searched in this form. The various capabilities needed by ACES are defined as grid services, which are conformant with emerging standards and implemented with different levels of fidelity and performance appropriate to the application. Grid Services can be composed in a hierarchical fashion to address complex problems. The real-time needs of the field are addressed by high-performance implementation of data transfer and simulation services. Further, the environment is linked to real-time collaboration to support interactions between scientists in geographically distant locations. Copyright © 2002 John Wiley & Sons, Ltd. [source] Timeliness and effectiveness in the surgical management of persistent post-treatment periapical pathosisENDODONTIC TOPICS, Issue 1 2005MIN-KAI WU Common problems that cause persistent post-treatment periapical pathosis include infection remaining in the apical inaccessible areas, extraradicular infection including apically extruded dentine debris with bacteria present in dentinal tubules, radicular true cysts, foreign body reactions, inadequate non-surgical root canal treatment with or without iatrogenically altered root canal morphology, and vertical root fractures. Inadequate root canal treatment may be corrected non-surgically, while more complex problems may require surgical intervention. The important factors that warrant a successful surgery include good quality of the orthograde root canal treatment, deep retrograde preparation of the apical canal, and carefully cleaning and filling of the exposed isthmuses and accessory canals. Ideally, apical surgery and orthograde retreatment are performed simultaneously. In a recent study, 97% of the lesions including large ones of >10 mm in diameter healed completely within 1 year after surgical intervention. Of the teeth that showed ,complete healing' at 4 years more than 85% already ,completely healed' at 2 years; thus, the endodontic post-treatment disease might be treated surgically or non-surgically within 2 years after the previous treatment. [source] An Approach to Interdisciplinary Training in Postgraduate EducationEUROPEAN JOURNAL OF DENTAL EDUCATION, Issue 2 2006P Brodin Aims, A primary goal for clinical graduate training is to provide the student with the expertise required for specialist treatment in the actual discipline. At the same time there is an increasing need for a broader perspective on specialist care and the students should be aware of the limitations inherent in own specialty. In order to plan treatment in the best interest of the patient, and to be prepared to take part in treatments involving other specialties, the students should be exposed to interdisciplinary cooperation throughout the training. An approach to joint academic and clinical training with the purpose of providing graduate students with a broader perspective on specialist care is described and discussed. Material and methods, During their first year graduate students in the 7 different disciplines complete a joint Core Curriculum consisting of 8 different courses to stimulate a scientific approach to their profession and understanding of basic biologic mechanisms. To create a learning environment focusing on the development of interdisciplinary competence, a joint clinic has been established. Teams of students from different disciplines have been organized in order to establish ,partnership' for the treatment of patients with complex problems. The students also take part in the sessions held by a faculty Team of experts for assessment and treatment planning of referred patients with complex problems. Furthermore, faculty members conduct courses and seminars for students from other disciplines and students also participate in selected parts of the regular program in other disciplines. Results, Formal evaluation has so far been conducted for the Core Curriculum. Most students respond that they are satisfied with the courses, and the curriculum has also been adjusted based on the comments. The students report that treatment of patients in need of interdisciplinary treatment has been facilitated by having ,partners' in other disciplines. Participation in the Team of expert's sessions has been appreciated, and the attendance at interdisciplinary courses and seminars has been good. Conclusions, Based on the experience over the last 5 years, the interdisciplinary aspects of graduate training should be expanded to stimulate a holistic approach also to specialist treatment. [source] Memetic evolutionary training for recurrent neural networks: an application to time-series predictionEXPERT SYSTEMS, Issue 2 2006M. Delgado Abstract: Artificial neural networks are bio-inspired mathematical models that have been widely used to solve complex problems. The training of a neural network is an important issue to deal with, since traditional gradient-based algorithms become easily trapped in local optimal solutions, therefore increasing the time taken in the experimental step. This problem is greater in recurrent neural networks, where the gradient propagation across the recurrence makes the training difficult for long-term dependences. On the other hand, evolutionary algorithms are search and optimization techniques which have been proved to solve many problems effectively. In the case of recurrent neural networks, the training using evolutionary algorithms has provided promising results. In this work, we propose two hybrid evolutionary algorithms as an alternative to improve the training of dynamic recurrent neural networks. The experimental section makes a comparative study of the algorithms proposed, to train Elman recurrent neural networks in time-series prediction problems. [source] Trust, power and interorganizational information systems: the case of the electronic trading community TransLeaseINFORMATION SYSTEMS JOURNAL, Issue 1 2000David K. Allen Abstract. This paper focuses on Cap Gemini's electronic commerce system, TransLease. TransLease is an interorganizational information system (IOS), which facilitates electronic commerce between motor vehicle leasing and repair companies. During our investigation, the system was used by approximately 1000 repair agents working for seven of the UK's leading vehicle leasing and contract hire companies. This system was originally developed by AT&T and acquired by Cap Gemini in July 1998. At the time of acquisition, the system was seen as being of high strategic value, although it was also seen as underperforming. This paper reports the results of an action research project, which formed one element of the process by which Cap Gemini investigated the former problem. In the paper, TransLease is described as a complex electronic community, dependent upon the existence of symbiotic relationships. As such, the problems that the system users and developers experienced can be attributed to factors that impeded the mutual benefit accruing from participation in the system. The efficacy of the terms of exchange and the degree to which participants mutually benefit through electronic interaction is determined by the complex interplay of a number of relational and organizational factors. The research therefore illustrates the importance of the ,soft' organizational issues in IOS management and development, and suggests a conceptual model of the factors relevant in this case. At the time of this study, TransLease was still in the early stages of its life cycle, having only been available in the marketplace for approximately 18 months. During this time, through recognizing the complex problems and issues detailed in this paper, Cap Gemini accordingly redressed the way in which the system was managed and maintained. TransLease is now seen as having matured into a highly successful example of an IOS , a view reflected by its position as market leader in the industry. As this paper will show, the key to improving the existing service has been the emphasis Cap Gemini now places on managing the ,soft' aspects of the electronic community. [source] Natural gradient algorithm for neural networks applied to non-linear high power amplifiers,INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 8 2002H. Abdulkader Abstract This paper investigates the processing techniques for non-linear high power amplifiers (HPA) using neural networks (NNs). Several applications are presented: Identification and Predistortion of the HPA. Various Neural Network structures are proposed to identify and predistort the HPA. Since a few decades, NNs have shown excellent performance in solving complex problems (like classification, recognition, etc.) but usually they suffer from slow convergence speed. Here, we propose to use the natural gradient instead of the classical ordinary gradient in order to enhance the convergence properties. Results are presented concerning identification and predistortion using classical and natural gradient. Practical implementations issues are given at the end of the paper. Copyright © 2002 John Wiley & Sons, Ltd. [source] Strategic Teaching: Student Learning through Working the ProcessINTERNATIONAL JOURNAL OF ART & DESIGN EDUCATION, Issue 2 2010Nancy Spanbroek The designers of our future built environment must possess intellectual tools which will allow them to be disciplined, flexible and analytical thinkers, able to address and resolve new and complex problems. In response, an experimental and collaborative design studio was designed to inspire and build on students' knowledge and their creative thinking abilities through a series of explorative exercises and modelling. The learning experience of students undertaking this studio was enabled and guided by a collaboration of teachers experienced in both teaching and creative practice. A series of guest creative practitioners joined the studio's intensive 10-week hands-on workshop sessions within which students undertook set exercises. These creative research workshops then served to inform subsequent design development of the students' work through planning and documentation over a period of 4 weeks. Strategic teaching is central to the creative development process. The driving educational belief, as idea and practice, is that by bringing ideas to life in design, by working with full-scale three-dimensionality, students are able to cement their commitment to ,working the process', towards becoming excellent designers. This ambitious strategy enables students to work on the many different aspects of the design problem towards meeting their design outcome at the highest level of resolution and intent. Through a combination of pragmatic tasks , writing and developing design briefs , and visual tasks , evidence gathering and analysis of design through photographic, modelling and diagramming exercises , students were encouraged to think outside and beyond the ,normal' realm of design practice. 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