Symmetry-guided nonrigid registration: the case for distortion correction in multidimensional photoemission spectroscopy

Image symmetrization is an effective strategy to correct symmetry distortion in experimental data for which symmetry is essential in the subsequent analysis. In the process, a coordinate transform, the symmetrization transform, is required to undo the distortion. The transform may be determined by image registration (i.e. alignment) with symmetry constraints imposed in the registration target and in the iterative parameter tuning, which we call symmetry-guided registration. An example use case of image symmetrization is found in electronic band structure mapping by multidimensional photoemission spectroscopy, which employs a 3D time-of-flight detector to measure electrons sorted into the momentum ($k_x$, $k_y$) and energy ($E$) coordinates. In reality, imperfect instrument design, sample geometry and experimental settings cause distortion of the photoelectron trajectories and, therefore, the symmetry in the measured band structure, which hinders the full understanding and use of the volumetric datasets. We demonstrate that symmetry-guided registration can correct the symmetry distortion in the momentum-resolved photoemission patterns. Using proposed symmetry metrics, we show quantitatively that the iterative approach to symmetrization outperforms its non-iterative counterpart in the restored symmetry of the outcome while preserving the average shape of the photoemission pattern. Our approach is generalizable to distortion corrections in different types of symmetries and should also find applications in other experimental methods that produce images with similar features

The Distribution of Occlusal Load in the Human Mandible: A Photoelastic Study

This study is an investigation of the distribution of occlusal load in replicas of the dentate and edentulous human mandible by the method of three dimensional photoelastic stress analysis. The study was stimulated by an interest in the occlusion of the teeth and in the relationship between disorders of the occlusion and the development of pain or dysfunction in the stomatognathic system. A further interest was in the association of faults in the design of complete dentures with pain in the oral tissues underlying the denture base. The distribution of load in any bone is related to the form and structure of the bone and to the type of loading to which the bone is normally subjected. The anatomical and biomechanical techniques which may be used to investigate these factors were developed for the study of the long bones of the limbs and in particular for the study of the human femur. The methods have been outlined, their limitations highlighted and their results compared. The general agreement of the results is quite striking. The application of these methods to the structural analysis of the human mandible has demonstrated the way in which the bone is reinforced to meet the loads imposed by masticatory function. Relatively few studies have been reported in which the hypotheses developed from anatomical investigations have been tested by other methods. Photoelastic stress analysis was selected as a method which would provide a visual demonstration of the distribution of load in the mandible and which offered the additional benefit that stresses could be studied in sections cut from the photoelastic models. As one of the interests in this study was the distribution of load in replicas of the edentulous mandible when load was applied in a number of different ways to a mandibular complete denture base, the theories of complete denture design have been reviewed, with emphasis on the relationship between the design of the dentures and the transmission of forces to the underlying tissues. The anatomy of the mandible and of the muscles of mastication and the temporo-mandibular joint has also been described. In order to relate the experimental procedures in this study to the clinical conditions under which load is applied to the mandible, it was necessary to construct a frame in which the photoelastic models could be supported in a position simulating centric relation of the mandible to the cranium. The lines of action of these muscles were determined by radiographic and cephalometric methods and a supporting frame was constructed to represent the base of skull, with metal struts aligned to correspond to the angulation of the muscles. While the shortcomings of this method were recognised, the model system provided adequate support for the models and no movement of the models or of the supporting elements was observed during the loading cycle. The principles of polarisation, birefringence and photoelasticity have been explained in detail. The methods of photoelastic stress analysis have been outlined, the preparation of models described and the techniques of stress freezing and three dimensional stress analysis presented. A detailed description has then been given of the preparation of photoelastic replicas of a dentate and of an edentulous human mandible. Weights were suspended from the dentate replicas to simulate bilateral loading in the molar region, loading in the incisor region and unilateral loading in the molar region. The same loads were applied to the edentulous mandible through the medium of a complete denture base. The distribution of load beneath an underextended denture base and of a subperiosteal implant were also studied. Isochromatic fringe patterns were recorded on the right and left halves of each replica and on sections cut from selected areas of the mandibular body and ramus. Isoclinics were studied in sections from the neck of the mandible. Fringe patterns in the hemisectioned specimens of the dentate and edentulous replicas were basically similar and indicated that stress had been generated in those areas of the models corresponding to the sites of major reinforcement of the structure of the mandible. Changes in the manner of loading were reflected in alterations in the pattern of stress distribution which suggested that greater stresses were transmitted to the condylar region when load was applied in the incisor region or when unilateral loading was used. Sections through the edentulous models suggested that when the experimental conditions were in accord with accepted principles of complete denture construction, load was distributed to the outer portion of the model, corresponding to the thickened cortical areas of the mandible. The simulation of occlusal faults and the use of an underextended denture base produced unfavourable distribution of load and provided experimental confirmation of accepted techniques of complete denture construction. A strain gauge study was then undertaken to confirm the results of the photoelastic method and a study of the optical properties of bone was also made, which suggested that a pattern of birefringence exists in bone and that it may be modified by the application of load in a manner similar to that in which fringe patterns are generated in photoelastic models

Reforming Maine\u27s Education Funding Process

In recent years funding for Maine K-12 education has been a source of almost constant dissension. As authors Patrick Dow and Ralph Townsend note, much of this dissension began in the early 1990s with the legislature\u27s decision to reduce funding for local education. Shrinking community budgets for local education have led to political battles over who gets what and have led to changes in the school funding formula established in the 1970s. The authors argue that these changes have eroded the principles of equity on which the 1970s formula was built. They trace the history of education funding in Maine, explain the mechanics of the current funding formula, and assess the impacts of recent changes to the formula. They conclude with a set of recommendations that call for, in part, setting a realistic local operating cost mill rate; the removal of income and cost of living from the formula; and modifications to the circuit breaker and homestead-exemption programs

Using Semantic Web Services for AI-Based Research in Industry 4.0

The transition to Industry 4.0 requires smart manufacturing systems that are easily configurable and provide a high level of flexibility during manufacturing in order to achieve mass customization or to support cloud manufacturing. To realize this, Cyber-Physical Systems (CPSs) combined with Artificial Intelligence (AI) methods find their way into manufacturing shop floors. For using AI methods in the context of Industry 4.0, semantic web services are indispensable to provide a reasonable abstraction of the underlying manufacturing capabilities. In this paper, we present semantic web services for AI-based research in Industry 4.0. Therefore, we developed more than 300 semantic web services for a physical simulation factory based on Web Ontology Language for Web Services (OWL-S) and Web Service Modeling Ontology (WSMO) and linked them to an already existing domain ontology for intelligent manufacturing control. Suitable for the requirements of CPS environments, our pre- and postconditions are verified in near real-time by invoking other semantic web services in contrast to complex reasoning within the knowledge base. Finally, we evaluate our implementation by executing a cyber-physical workflow composed of semantic web services using a workflow management system.Comment: Submitted to ISWC 202

Evaluation of Storage Reallocation and Related Strategies for Optimizing Reservoir System Operations

Statement of the Problem Rapid population and economic growth combined with depleting groundwater reserves are resulting in ever increasing demands on surface water resources in Texas, as well as elsewhere. The climate of the state is characterized by extremes of floods and droughts. Reservoirs are necessary to control and utilize the highly variable streamflow. Due to a number of economic, environmental, institutional, and political considerations, construction of new reservoir projects is much more difficult now than in the past. Consequently, optimizing the beneficial use of existing reservoirs is becoming increasingly more important. Reservoir operation is based on the conflicting objectives of maximizing the amount of water available for conservation purposes and maximizing the amount of empty space available for storing future flood waters to reduce downstream damages. Common practice is to operate a reservoir for either flood control only, conservation only, or a combination of flood control and conservation with separate pools designated for each. The conservation and flood control pools, or vertical zones, in a multipurpose project are fixed by a designated top of conservation (bottom of flood control) pool elevation. Conservation pools may be shared by various purposes, such as water supply, hydroelectric power, and recreation, which involve both complementary and conflicting interactions. Public needs and objectives and numerous factors affecting reservoir operation change over time. An increasing necessity to use limited storage capacity as effectively as possible warrants periodic re-evaluations of operating policies. Reallocation of storage capacity between purposes represents a general strategy for optimizing the beneficial use of limited storage capacity in response to changing needs and conditions. A storage reallocation between flood control and conservation purposes typically involves a permanent or seasonal change in the designated top of conservation pool elevation. Reallocations between conservation purposes can be achieved by various modifications of operating policies. Although given relatively little consideration in the past, storage reallocations will likely be proposed more frequently as demands on limited resources increase. Scope of Study This report documents an investigation of: (1) the potential of storage capacity reallocation and other related modifications in operating policies as management strategies for optimizing the beneficial use of existing reservoirs in Texas and (2) modeling capabilities for formulating and evaluating such changes to operating policies. In general, storage reallocations can involve a variety of types of reservoir use. The present study focused primarily on flood control and water supply. Multiple purpose reservoir operations involving hydroelectric power were also investigated. Both permanent conversion of storage capacity between purposes and seasonal rule curve operations were addressed. Buffer pool operations were also considered. Multiple reservoir system operation was a major emphasis of the study. The literature was reviewed and several reservoir management agencies contacted to (1) identify experiences in studying and/or implementing storage reallocations and (2) evaluate the state-of-the-art of associated modeling and analysis capabilities. The feasibility of seasonal rule curve operation depends upon the seasonal characteristics of the various factors affecting reservoir operation. Precipitation, streamflow, reservoir evaporation, water demands, and reservoir storage content data for Texas were analyzed to identify seasonal characteristics. A 12-reservoir system operated by the U.S. Army Corps of Engineers and Brazos River Authority provided a case study for evaluating the potential for storage reallocations and related operating strategies. This system, located in the Brazos River Basin, is considered representative of major reservoirs in Texas. The existing operating policies and possible modifications were investigated. The case study includes (1) flood control storage frequency and conservation drawdown frequency analyses based on the results of monthly hydrologic period-of-record simulations of reservoir system operations and (2) firm yield and reliability analyses. The generalized computer programs HEC-3, HEC-5, STATS, and MOSS-IV, and several utility software packages were used in the modeling study. Simulation of reservoir system operations was based on an 85-year sequence of monthly hydrologic data. The case study provides a preliminary assessment of the viability of permanent storage conversions and/or adoption of seasonal rule curve operations as potential reservoir management strategies. The objective is to evaluate storage reallocation potentialities in general, not develop detailed reallocation plans. The case study is basically a reconnaissance-level hydrologic analysis of reservoir operations. The monthly period-of-record simulations provide a reasonably precise analysis of water supply considerations. However, the daily hydrologic data required for detailed analysis of flood control operations were not included in the study. Reallocation of reservoir storage capacity involves complex institutional, financial, economic, legal, political, and technical considerations not addressed in the case study. However, the hydrologic analyses provide a good starting point for determining what types of reallocation strategies and modeling approaches might be potentially effective and whether more detailed studies are worthwhile. Organization of the Report Chapter 2 is a general discussion of reservoir operation and institutional and technical aspects of storage reallocation and a review of reallocations which have been implemented or proposed throughout the nation. Chapter 3 addresses the seasonality of the hydrologic factors pertinent to seasonal rule curve operation in Texas. Chapter 4 reviews state-of-the-art modeling capabilities and describes the computer models adopted for use in the case study. The Brazos River Basin case study is presented in chapters 5 through 8. Study results are summarized, and conclusions are presented in chapter 9

Considerations for Rapidly Converging Genetic Algorithms Designed for Application to Problems with Expensive Evaluation Functions

A genetic algorithm is a technique designed to search large problem spaces using the Darwinian concepts of evolution. Solution representations are treated as living organisms. The procedure attempts to evolve increasingly superior solutions. As in natural genetics, however, there is no guarantee that the optimum organism will be produced. One of the problems in producing optimal organisms in a genetic algorithm is the difficulty of premature convergence. Premature convergence occurs when the organisms converge in similarity to a pattern which is sub-optimal, but insufficient genetic material is present to continue the search beyond this sub-optimal level, called a local maximum. The prevention of premature convergence of the organisms is crucial to the success of most genetic algorithms. In order to prevent such convergence, numerous operators have been developed and refined. All such operators, however, rely on the property of the underlying problem that the evaluation of individuals is a computationally inexpensive process. In this paper, the design of genetic algorithms which intentionally converge rapidly is addressed. The design considerations are outlined, and the concept is applied to an NP-Complete problem, known as a Crozzle, which does not have an inexpensive evaluation function. This property would normally make the Crozzle unsuitable for processing by a genetic algorithm. It is shown that a rapidly converging genetic algorithm can successfully reduce the effective complexity of the problem

Motivations To Produce User Generated Content: Differences Between Webloggers And Videobloggers

This explorational study seeks to elucidate the question of what motivates weblogger and videoblogger to produce user generated content. Particular focus was laid on the question whether motivational differences can be discerned between webloggers and video producers and why people do not produce content. The findings show that it is the intrinsic motivations that are responsible for today’s user generated content. Video producers and webloggers differ in their motivations. Video production is more associated with fun and time passing than is weblogging. Weblogging is regarded as being more useful in the dissemination of information. The main reasons for not producing content are opportunity costs and privacy issues

Earth Observation – A Fundamental Input for Crisis Information Systems

Space-borne and airborne earth observation (EO) is a highly valuable source of spatio-temporal information promoting the ability for a rapid up-to-date assessment and (near-) real-time monitoring of natural or and man-made hazards and disasters. Such information has become indispensable in present-day disaster management activities. Thereby, EO based technologies have a role to play in each of the four phases of the disaster management cycle (i.e. mitigation, preparedness, response and recovery) with applications grouped into three main stages: - Pre-disaster (preparedness and mitigation): EO-based information extraction for assessing potential spatial distributions and severities of hazards as well as the vulnerability of a focus region for disaster risk evaluation and subsequent mitigation and preparedness activities. - Event crisis (response): Assessment and monitoring of regional extent and severities of the characteristics and impacts of a disaster to assist rapid crisis management. - Post-disaster (recovery): EO based information extraction to assist recovery activities. Within the PHAROS system a wide range of data products are used, which are varying in temporal, spatial and spectral resolution and coverage. The used sensor platforms comprise space-borne satellites and airborne systems, i.e. aircrafts as well as unmanned aerial systems (UAS)

Spectral Effects of Strong Chi-2 Non-Linearity for Quantum Processing

Optical $\chi^{(2)}$ non-linearity can be used for parametric amplification and producing down-converted entangled photon pairs that have broad applications. It is known that weak non-linear media exhibit dispersion and produce a frequency response. It is therefore of interest to know how spectral effects of a strong $\chi^{(2)}$ crystal affect the performance. Here we model the spectral effects of the dispersion of a strong $\chi^{(2)}$ crystal and illustrate how this affects its ability to perform Bell measurements and influence the performance of a quantum gates that employ such a Bell measurement. We show that a Dyson series expansion of the unitary operator is necessary in general, leading to unwanted spectral entanglement. We identify a limiting situation employing periodic poling, in which a Taylor series expansion is a good approximation and this entanglement can be removed.Comment: Will be submitted to PR