Exhaustive Scenario Research Articles

Principal component pyramids for manifold learning in hand shape recognition

Abstract This paper presents two algorithms using data pyramids for hand shape recognition in Irish Sign Language. Principal Component Analysis (PCA) is used as a feature extraction and dimensionality reduction method. Originally, the problem is nonlinear and it is hard for PCA to extract the underlying structure of the data. The proposed PCA pyramids provide an alternative to nonlinear PCA as they depend on dividing the space into subspaces which are approximately linear using the appropriate eigenspace in each level. They are used to accelerate the search process to approximate the nearest neighbour search problem. The first algorithm uses unsupervised multidimensional grids to cluster the space into cells of similar objects. The second algorithm is based on training a set of simple architecture multilayer neural networks. Experimental results are given to measure the accuracy and performance of the proposed algorithms in comparison with the exhaustive search scenario. The proposed algorithms are applicable for real time applications with high accuracy measures.

Optimal control of HVAC and window systems for natural ventilation through reinforcement learning

Natural ventilation is a green building strategy that improves building energy efficiency, indoor thermal environment, and air quality. However, in practice, it is not always clear when and how to utilize the natural ventilation and coordinate its operation with the HVAC system. This paper introduces a reinforcement learning control strategy, specifically through model-free Q-learning, that makes optimal control decisions for HVAC and window systems to minimize both energy consumption and thermal discomfort. This control system evaluates the outdoor and indoor environments (temperature, humidity, solar radiation, and wind speed) at each time step, and responds with the best control decision that targets both immediate and long-term goals. The reinforcement learning control is evaluated through numerical simulation on a building thermal model and compared with a rule-based heuristic control strategy. Case studies in hot-and-humid Miami and warm-and-mild Los Angeles demonstrated the superior performance of reinforcement learning control, which led to 13% and 23% lower HVAC system energy consumption, 62% and 80% lower discomfort degree hours, and 63% and 77% fewer high humidity hours compared to heuristic control. Unlike heuristic control that requires specific knowledge of individual buildings and the creation of exhaustive decision-making scenarios to improve performance, reinforcement learning control guarantees optimality through self-advancement on given goals and cost functions and is able to adapt to stochastic occupancy and occupant behaviors, which is difficult to accommodate by heuristic control.

Experimental study of heating scheme effect on the inner divertor power footprint widths in EAST lower single null discharges

A comprehensive work of the effects of plasma current and heating schemes on divertor power footprint widths is carried out in the experimental advanced superconducting tokamak (EAST). The divertor power footprint widths, i.e., the scrape-off layer heat flux decay length λq and the heat spreading S, are crucial physical and engineering parameters for fusion reactors. Strong inverse scaling of λq and S with plasma current have been demonstrated for both neutral beam (NB) and lower hybrid wave (LHW) heated L-mode and H-mode plasmas at the inner divertor target. For plasmas heated by the combination of the two kinds of auxiliary heating schemes (NB and LHW), the divertor power widths tend to be larger in plasmas with higher ratio of LHW power. Comparison between experimental heat flux profiles at outer mid-plane (OMP) and divertor target for NB heated and LHW heated L-mode plasmas reveals that the magnetic topology changes induced by LHW may be the main reason to the wider divertor power widths in LHW heated discharges. The effect of heating schemes on divertor peak heat flux has also been investigated, and it is found that LHW heated discharges tend to have a lower divertor peak heat flux compared with NB heated discharges under similar input power. All these findings seem to suggest that plasmas with LHW auxiliary heating scheme are better heat exhaust scenarios for fusion reactors and should be the priorities for the design of next-step fusion reactors like China Fusion Engineering Test Reactor.

Impact of perturbative, non-axisymmetric impurity fueling on Alcator C-Mod H-modes

Experiments on Alcator C-Mod have been performed to investigate the impact of toroidally localized impurity injection on H-mode exhaust scenarios. Results help to inform sub-divertor gas injector designs, in particular that of the ITER machine, for which this work was primarily undertaken. In repeated EDA H-modes, the amount of N2 injected into the private flux region was scanned up to levels which strongly impacted normalized energy confinement, H98, and led to an H/L back-transition. Repeated scans increased the toroidal peaking of the gas injection, reducing from five equally spaced locations to a single toroidal and poloidal injector. Results show the impact on the pedestal and core plasma is similar between all cases as long as the total gas injection rate is held constant. An influence on toroidally localized impurity spectroscopy is shown, demonstrating a complication in using such data in interpreting experiments and supporting boundary modeling in cases where there are localized extrinsic or intrinsic impurity sources. These results, along with prior work in this area on Alcator C-Mod, form a comprehensive set of L-mode and H-mode data to be used for validation of 3D boundary physics codes.

3D effects on transport and plasma control in the TJ-II stellarator

The effects of 3D geometry are explored in TJ-II from two relevant points of view: neoclassical transport and modification of stability and dispersion relation of waves. Particle fuelling and impurity transport are studied considering the 3D transport properties, paying attention to both neoclassical transport and other possible mechanisms. The effects of the 3D magnetic topology on stability, confinement and Alfvén Eigenmodes properties are also explored, showing the possibility of controlling Alfvén modes by modifying the configuration; the onset of modes similar to geodesic acoustic modes are driven by fast electrons or fast ions; and the weak effect of magnetic well on confinement. Finally, we show innovative power exhaust scenarios using liquid metals.

Raman characterization of XIV–XVI centuries Sardinian documents: Inks, papers and parchments

Raman spectroscopy has been utilized to study ancient documents conserved at the University Library of Cagliari (Italy) with the aim to give an exhaustive scenario about the employment of inks, pigments and supporting materials (papers and parchments) related to specific historical periods (XIV–XV centuries). The samples studied are selected between the most prestigious texts present in the collection: two accounting books of sixteenth and fifteenth centuries, a mathematical text of the sixteenth century, a navigation text of the same period, a copy of the most important Sardinian medieval constitutional text “Carta De Logu”, a medieval copy of the famous Italian poem: “La Divina Commedia”. Finally we characterized a declared false of the nineteenth century reproducing a famous document of the XIII century.The present study gives fundamental knowledge on the history of different inks used in the manuscripts and also on the conservation as well degradation of supporting materials. In addition we focused our characterization on different techniques and materials applied in previous restorations. Finally, we certified with modern techniques the presence of deliberate falsification processes of some specimens.

A framework for generating prioritised test scenarios using firefly optimisation technique

The intention of this research is to generate test scenarios for concurrent and composite states in state machines using firefly optimisation algorithm. We have used state-based coverage criterion such as state coverage, transition coverage, transition pair coverage, etc. to evaluate the efficiency of our proposed algorithm. The proposed approach is useful for feasible test scenario generation. Generating exhaustive test scenarios for all concurrent interdependent sequences is exponential in size. As a result, in this paper, we find the important test scenarios in the presence of concurrency in composite models.

A framework for generating prioritised test scenarios using firefly optimisation technique

The intention of this research is to generate test scenarios for concurrent and composite states in state machines using firefly optimisation algorithm. We have used state-based coverage criterion such as state coverage, transition coverage, transition pair coverage, etc. to evaluate the efficiency of our proposed algorithm. The proposed approach is useful for feasible test scenario generation. Generating exhaustive test scenarios for all concurrent interdependent sequences is exponential in size. As a result, in this paper, we find the important test scenarios in the presence of concurrency in composite models.

Modelling and analysis of breathing-induced lung motion in swimming performance

Sporting was solely considered to be based on talent and physical capabilities in the past. Adaption of computer-aided engineering, particularly computational fluid dynamics, in sports-engineering has made significant advancements by developing concentrated techniques that could help individuals to reach their peak performance. Studies show that physical performance could be mainly limited by three main components, namely, muscular, cardiovascular and pulmonary systems. Due to inevitable limitations that exist in the pulmonary system, researchers are more concerned in training respiratory muscles. Inspiratory-muscle training is a well-known technique in many sports, particularly in high-intensity breathing-related sports such as rowing, cycling and swimming that require an individual’s aerobic capability and respiratory system with a high-minute ventilation to sustain exhaustive breathing scenarios. This article describes inspiratory-muscle training dynamics followed by a methodology for three-dimensional lung model to understand the interdependence of several control parameters for comparative performance, thereby generating an inverse control model for potential performance improvement criteria. The three-dimensional lung model is developed based on Visible Human Project® database, which provided detailed anatomical dimensions. The shape functions are constructed using cubic splines to fit tomographic slices. Parametric studies using variables such as pressure exerted by chest cavity on lungs, lung compliance, fluid-flow/volume, average elasticity for inspiratory-muscle training and breathing-time constants are conducted. Our hypothesis is based upon synchronising the position of lung centroids with working stroke execution, which can result in enhanced swimming performance. Simulation results showed that lung centroid could vary from 109.95E−5 to 109.99E−5 m, proving that there is a possibility to change the swimmer’s floatation angle by 0.036% during each swimming cycle. The lung centroid could be varied optimally by controlled breathing patterns. A typical swimmer with 25°–35° floatation angles can increase or decrease the floatation angles during recovery and gliding phases, respectively, by synchronising breathing patterns with the stroke during different phases of swimming cycle. Previous studies showed that the distance between lung centroid and body gravity can change up to 1.5 mm. Results obtained from our model equations showed that the change in displacement of lung centroid is 1.099 mm. Therefore, the variation of accuracy of our results is about 27% from the previous studies. However, results generated from our studies are generic, that is, results are gender independent, and the effect of body-to-lung ratio in stroke execution is not taken into consideration. These factors potentially provide a platform for further improvement in our simulation models.

Conservation of Plant Genetic Resources and Their Utilisation in Global Perspective

Plant genetic resources such as recent cultivars and breeds, traditional cultivars and breeds, special genetic livestocks (breeding lines, mutants, etc.), wild relatives of domesticated species are commonly used to study the genetical, evolutionary, physiological, cytological, breeding, pathological, environmental or ecological aspects of plants. Likewise, crop genetic resources are used by plant breeders to develop new and improved varieties having significant economic benefits. In the past due to overexploitation of naturally existing variability in a plant species exhausted substantially leading to a narrow genetic base of the plant species. Land races with narrow genetic base having a high risk of elimination by diseases or any other natural calamity. So, the present day need is to check the depletion of existing variability of a species of a gene pool. According to FAO, genetic erosion or the loss of genetic diversity is an issue of serious concern in relation to sustainable global food security. If we do not counteract with the rising genetic impoverishment it may have severe consequences in near future. Almost all the ecosystems and genetic resources are facing threats due to increasing pollution, invasive alien species, overexploitation by humans and climate change. Therefore, there is an urgent need for conservation, sustainable utilisation and management of plant genetic resources so as to meet the growing requirement of food, fodder, fibre, health and other needs of present as well as future generation. The conservation of wild relatives of crop plants and the offsite conservation of crop varieties and culture of microorganisms is a very necessary aspect. Some of the short-term and long-term programs for plant genetic conservation along with other measures such as sustainable consumption, taking pro-active steps to control climate changes, are needed to be emphasised. By adopting a number of the methodologies discussed in the review, plant genetic resources are being tried to conserve for future genetic advancement and an insurance against unpredicted threats to future agricultural production. The detailed and exhaustive scenario of the genetic resources, its conservation (ex situ and in situ) and application is also discussed in depth in this review.

High density operation for reactor-relevant power exhaust

With increasing size of a tokamak device and associated fusion power gain an increasing power flux density towards the divertor needs to be handled. A solution for handling this power flux is crucial for a safe and economic operation. Using purely geometric arguments in an ITER-like divertor this power flux can be reduced by approximately a factor 100. Based on a conservative extrapolation of current technology for an integrated engineering approach to remove power deposited on plasma facing components a further reduction of the power flux density via volumetric processes in the plasma by up to a factor of 50 is required. Our current ability to interpret existing power exhaust scenarios using numerical transport codes is analyzed and an operational scenario as a potential solution for ITER like divertors under high density and highly radiating reactor-relevant conditions is presented. Alternative concepts for risk mitigation as well as strategies for moving forward are outlined.

Energy Management of Through-The-Road Parallel Hybrid Vehicles

The paper presents a study on optimal energy management of through-the-road parallel hybrid vehicles, obtainable by suitably upgrading existing conventional cars. The main features and potential benefits associated to such a mild, after-market hybridization are firstly discussed, before introducing main methodological aspects, both in terms of mathematical modeling approach and benchmarks for realtime implementable control strategies. Then, a dynamic programming optimization procedure was set-up, thus allowing performing an exhaustive scenario analysis. The outcomes of such an analysis allow evaluating the fuel saving margins, within which it is possible to fall depending on the selected through-the-road vehicle architecture. Particularly, it is possible to quantify the fuel saving potential of the specific hybrid vehicle topology here examined, on one hand, and, on the other, to establish the reference benchmark, addressed by dynamic-programming derived optimality level, to which to refer when developing real-time energy management policies.

Assessment of DEMO challenges in technology and physics

The challenges that DEMO designs encounter in both technology and physics are reviewed. It is shown that it is very important to respect the interlinks between these fields when developing designs for DEMO. Examples for areas where such interlinks put very strict requirements are the development of a steady state tokamak operation scenario and the question of power exhaust taking into account the boundary conditions set by materials questions. Concerning steady state operation, we find that demands on the physics scenario are so high that pulsed operation of a tokamak DEMO should seriously be considered in conservative DEMO designs. Alternatively, the device could foresee a large fraction of externally driven current which calls for optimization of both plasma CD efficiency as well as wall plug efficiency of the CD system. In the exhaust area, a realistic estimate of the admissable time averaged peak heat flux at the target is of the order of 5MW/m2, leading to strict requirements for the operational scenario, which has to rely on an unprecedented high level of radiation loss by impurity seeding and the facilitation of partial detachment. Thus, exhaust scenarios along these lines have to be developed which are compatible with the confinement needs and the H-L back transition power for DEMO. In both areas, we discuss possible risk mitigation strategies based on conceptually different approaches.

Magnetorheological damper—an experimental study

A magnetorheological damper is evaluated under exhaustive experimental scenarios, generating a complete database. The obtained database includes classical tests and new proposals emphasizing the frequency contents. It also includes the impact of the electric current fluctuations. The variety of the performed experiments allows us to study the magnetorheological damper force dynamics. A brief description of the damper behavior and a categorization of experiments based on driving conditions and target applications on vehicle dynamics are discussed. The identification of two magnetorheological damper models and their cross validation emphasize the importance of the persistence of experimental inputs and the combinations of rod displacement and electric current sequences for better modeling. New findings in design of experiments for model identification are presented.

Completing Correlation Matrices of Arbitrary Order by Differential Evolution Method of Global Optimization: A Fortran Program

Correlation matrices have many applications, particularly in marketing and financial economics. The need to forecast demand for a group of products in order to realize savings by properly managing inventories requires the use of correlation matrices. In many cases, due to paucity of data/information or dynamic nature of the problem at hand, it is not possible to obtain a complete correlation matrix. Some elements of the matrix are unknown. Several methods exist that obtain valid complete correlation matrices from incomplete correlation matrices. In view of non-unique solutions admissible to the problem of completing the correlation matrix, some authors have suggested numerical methods that provide ranges to different unknown elements. However, they are limited to very small matrices up to order 4. Our objective in this paper is to suggest a method (and provide a Fortran program) that completes a given incomplete correlation matrix of an arbitrary order. The method proposed here has an advantage over other algorithms due to its ability to present a scenario of valid correlation matrices that might be obtained from a given incomplete matrix of an arbitrary order. The analyst may choose some particular matrices, most suitable to his purpose, from among those output matrices. Further, unlike other methods, it has no restriction on the distribution of holes over the entire matrix, nor the analyst has to interactively feed elements of the matrix sequentially, which might be quite inconvenient for larger matrices. It is flexible and by merely choosing larger population size one might obtain a more exhaustive scenario of valid matrices. Moreover, the Differential Evolution algorithm is amenable to parallelization.

Integrated exhaust scenarios with actively controlled ELMs

An integrated radiative high performance scenario has been established at ASDEX Upgrade based on simultaneous feedback control of the average divertor neutral particle and power flux in combination with a high, pellet induced frequency of edge localized modes (ELMs). This approach is fully compatible with the present tungsten wall coating covering about 65% of the plasma facing components and is intended for application in the envisaged full-tungsten experiment. In these experiments, divertor recycling and effective divertor temperature (derived from thermoelectric currents) were tuned by acting on fuel gas puff and argon injection rates. The ELM frequency (fELM) was kept high by repetitive injection of small cryogenic deuterium pellets to avoid the radiative instabilities seen at low fELM and high radiated power, and to control the ELM energy. No confinement loss is observed in this radiative type-I ELMy scenario with relatively flat density profiles. In contrast, similar type-III ELM scenarios achieved in hydrogen show a confinement loss of 25% as compared to the type-I phase. In parallel to pellets, alternative ELM trigger techniques have been investigated as well. Fast vertical plasma oscillations are able to synchronize the ELM frequency to values higher and lower than the intrinsic fELM, but remain to be tested in the integrated scenario. Supersonic gas injection showed better fuelling efficiencies than usual gas puffing but instantaneous ELM release has not been achieved. A particular experimental challenge for AUG conditions is to obtain a high pace making frequency, to establish scalings of confinement and energy loss as a function of controlled ELM frequency.

Subjective Probability under Additive Aggregation of Conditional Preferences

This paper provides an axiomatic basis for a representation of personal preferences in which the utility of an act can be expressed as an expected value of conditional utilities of the act given any set of mutually exclusive and exhaustive scenarios, under a unique subjective probability. The representation is general enough to incorporate state-dependent utilities and/or utilities with dependencies across states, as, for example, in the case of disappointment aversion. More generally, this is a model incorporating subjective probability and subjective consequences, since neither probabilities nor consequences are included among its primitives. The model reduces to subjective expected utility under the additional assumptions of separability and state-independence with respect to an objective state-contingent structure of acts.Journal of Economic LiteratureClassification Numbers: D81, D84.

Futures assessment by field anomaly relaxation: A review and appraisal

Futures research includes the problem of generating reasonably exhaustive and plausible scenarios for a given topic, a problem for which there are no truly satisfactory solutions. This article reviews and evaluates a method, field anomaly relaxation, first put forward some 20 years ago. The evaluation is in the context of an illustrative study of political developments in Europe. The research reconstructs and further develops the method and concludes that it has something to offer for scenario generation. Its weaknesses are identified and suggestions for further research are made.