1,563 research outputs found
Generating Strong Diversity of Opinions: Agent Models of Continuous Opinion Dynamics
Opinion dynamics is the study of how opinions in a group of individuals change over time. A goal of opinion dynamics modelers has long been to find a social science-based model that generates strong diversity -- smooth, stable, possibly multi-modal distributions of opinions. This research lays the foundations for and develops such a model. First, a taxonomy is developed to precisely describe agent schedules in an opinion dynamics model. The importance of scheduling is shown with applications to generalized forms of two models. Next, the meta-contrast influence field (MIF) model is defined. It is rooted in self-categorization theory and improves on the existing meta-contrast model by providing a properly scaled, continuous influence basis. Finally, the MIF-Local Repulsion (MIF-LR) model is developed and presented. This augments the MIF model with a formulation of uniqueness theory. The MIF-LR model generates strong diversity. An application of the model shows that partisan polarization can be explained by increased non-local social ties enabled by communications technology
Forecasting Effects of Influence Operations: A Generative Social Science Methodology
Simulation enables analysis of social systems that would be difficult or unethical to experiment upon directly. Agent-based models have been used successfully in the field of generative social science to discover parsimonious sets of factors that generate social behavior. This methodology provides an avenue to explore the spread of anti-government sentiment in populations and to compare the effects of potential Military Information Support Operations (MISO) actions. This research develops an agent-based model to investigate factors that affect the growth of rebel uprisings in a notional population. It adds to the civil violence model developed by Epstein (2006) by enabling communication between agents in the manner of a genetic algorithm and friendships based on shared beliefs. A designed experiment is performed. Additionally, two counter-propaganda strategies are compared and explored. Analysis identifies factors that have effects that can explain some real-world observations, and provides a methodology for MISO operators to compare the effectiveness of potential actions
Introduction to the special issue āIntegrated scenario building in energy transition research
Adaptive governance approaches emphasize the crucial role of the private sector in enabling climate change adaptation. Yet, the participation of local firms is still lacking, and little is known about the conditions potentially influencing firmsā adaptation decisions and mechanisms that might encourage private sector engagement. We address this gap with an empirical analysis of the willingness of manufacturing small- and medium-sized enterprises (SMEs) to participate financially in collective flood adaptation in Ho Chi Minh City (HCMC), a hotspot of future climate change risk. Using scenario-based field experiments, we shed light on internal and external conditions that influence potential investments in collective initiatives and explain what role SMEs can play in flood adaptation. We find that direct impacts of floods, perceived self-responsibility, and strong local ties motivate firms to participate in collective adaptation, whereas government support, sufficient financial resources, and previously implemented flood protection strategies reduce the necessity to act collectively. Here, opportunity costs and the handling of other business risks play a decisive role in investment decisions. This study shows that although private sector engagement appears to be a promising approach, it is not a panacea. Collective initiatives on flood adaptation need formal guidance and should involve local business networks and partnerships to give voice to the needs and capacities of SMEs, but such initiatives should not overstretch firmsā responsibilities
Scanning tunneling microscopy investigation of 2H-MoS_2: A layered semiconducting transitionāmetal dichalcogenide
Scanning tunneling microscopy (STM) has been enormously
successful in solving several important problems in the geometric and electronic structure of homogeneous metallic and semiconducting surfaces. A central question which remains to be answered with respect to the study of
compound surfaces, however, is the extent to which the
chemical identity of constituent atoms may be established.
Recently, progress in this area was made by Feenstra et al.
who succeeded in selectively imaging either Ga or As atoms
on the GaAs (110) surface. So far this is the only case where such selectivity has been achieved. In an effort to add to our understanding of compound surface imaging we have undertaken a vacuum STM study of 2H-MoS_2, a material which has two structurally and electronically different atomic species at its surface
Highly Porous Ceramic Material and Method of using and Forming the Same
The present invention generally relates to porous ceramic material and to methods of making and using the material. More particularly, the invention relates to methods of forming ceramic materials by depositing material, using atomic layer deposition, onto a sacrificial substrate and to ceramic materials having controlled wall thickness, relatively large pores, and high surface area by weight
Spectroscopic Temperature Measurements for a Direct Current Arcjet Diamond Chemical Vapor Deposition Reactor
The diamond thin filmcommercial market isprojected to exceed one billion dollars by the year 2000. Potential applications of diamond thin films range from cutting tools to electronics tomedical devices. The explosion ofinterest in this fieldresults from the extreme properties diamond possesses: itis the hardest material known toman and yet, has a coefficient of friction similar to Teflon;its ability to conduct heat is five times that of copper; and diamond is completely inert. However, despite the tremendous economic incentive, there are still several technological barriers preventing diamond filmscale-up to commercial production. Included among these are a fundamental understanding of the gas phase chemistry leading to diamond filmformation and the lack of a reliable insitu, on-line Chemical Vapor Deposition (CVD)monitoring capability. Here we describe the use of optical emission spectroscopy (OES) as a possible direct current CVD plasma jet on-line monitor. Specifically, OES spectra from the C2 radical, an intermediate species in the diamond CVD process, is utilized to obtain plasma gas temperatures insitu. Additionally, the reliability of a plasma gas temperature determined fromOES is examined withLaser-Induced-Fluorescence (LIF)
Spectroscopic Temperature Measurements for a Direct Current Arcjet Diamond Chemical Vapor Deposition Reactor
The diamond thin filmcommercial market isprojected to exceed one billion dollars by the year 2000. Potential applications of diamond thin films range from cutting tools to electronics tomedical devices. The explosion ofinterest in this fieldresults from the extreme properties diamond possesses: itis the hardest material known toman and yet, has a coefficient of friction similar to Teflon;its ability to conduct heat is five times that of copper; and diamond is completely inert. However, despite the tremendous economic incentive, there are still several technological barriers preventing diamond filmscale-up to commercial production. Included among these are a fundamental understanding of the gas phase chemistry leading to diamond filmformation and the lack of a reliable insitu, on-line Chemical Vapor Deposition (CVD)monitoring capability. Here we describe the use of optical emission spectroscopy (OES) as a possible direct current CVD plasma jet on-line monitor. Specifically, OES spectra from the C2 radical, an intermediate species in the diamond CVD process, is utilized to obtain plasma gas temperatures insitu. Additionally, the reliability of a plasma gas temperature determined fromOES is examined withLaser-Induced-Fluorescence (LIF)
Specialising Software for Different Downstream Applications Using Genetic Improvement and Code Transplantation
OAPA Genetic improvement uses computational search to improve existing software while retaining its partial functionality. Genetic improvement has previously been concerned with improving a system with respect to all possible usage scenarios. In this paper, we show how genetic improvement can also be used to achieve specialisation to a specific set of usage scenarios. We use genetic improvement to evolve faster versions of a C++ program, a Boolean satisfiability solver called MiniSAT, specialising it for three applications. Our specialised solvers achieve between 4% and 36% execution time improvement, which is commensurate with efficiency gains achievable using human expert optimisation for the general solver. We also use genetic improvement to evolve faster versions of an image processing tool called ImageMagick, utilising code from GraphicsMagick, another image processing tool which was forked from it. We specialise the format conversion functionality to black & amp; white images and colour images only. Our specialised versions achieve up to 3% execution time improvement
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