333 research outputs found
Unconventional bulk-Fermi-arc links paired third-order exceptional points splitting from a defective triple point
No full textAbstract Exceptional degeneracies, unique to open systems, are important in non-Hermitian topology. While bulk-Fermi-arcs connecting second-order exceptional points (EP2s) have been observed, the existence of bulk-Fermi-arcs linking higher-order exceptional points remains unexplored. Here, we introduce an unconventional bulk-Fermi-arc in systems with parity-time and pseudo-Hermitian symmetries, which links paired third-order exceptional points (EP3s), where three eigenvalues share identical real parts but distinct imaginary parts. We realize these systems using topological circuits and experimentally demonstrate this unconventional bulk-Fermi-arc. A winding number defined from resultant vector shows that the bulk-Fermi-arc is stabilized by the exchange of Riemannian sheets. Furthermore, analysis via eigenframe deformation and rotation reveals that the EP3 pair is topologically nontrivial and equivalent to a single defective triple point. The EP3s can split from the triple point by varying system parameters, with this splitting protected by topological equivalence. This finding offers insights into non-Hermitian topology with potential applications in wave engineering
Game Engine-based Point Cloud Visualization and Perception for Situation Awareness of Crisis Indoor Environments
No full textBecause unknown interior layouts can have serious consequences in time-sensitive situations, crisis response teams request many potential solutions for visualizing indoor environments in crisis scenarios. This research uses a game engine to directly visualize point cloud data input of indoor environments for generating clear interaction between the environment and viewers, to aid decision-making in high-stress moments. The prospective final product is an integration of game-oriented visualization and cartography, hosted within Unreal Engine 4 (UE4), allowing users to navigate throughout an indoor environment, and customizing certain interaction features. The UE4 project consists of 4 modules: data preprocessing, render style, functional module, and user interface. Finally, this research uses a single-floor indoor point cloud dataset collected from a building in Rotterdam, the Netherlands for the implementation.GIS Technologi
The impact of cultural values on email acceptance : evidence from the PRC
No full textGlobal deployment in information technology (IT) requires understandings of the cultural constraints in technology acceptance and usage behavior. Prior research indicates that the salient technology acceptance models may not be applicable to all cultures since empirical support was mainly obtained from North America. Cultural impact on user acceptance is still at the early stage of research. There has been little research done on technology acceptance and usage behavior in the context of China, which exhibits distinctive cultural differences from countries in North America. The purpose of this thesis is to test the cross-cultural applicability of Technology Acceptance Model in the People’s Republic of China (PRC), and to investigate the influence of cultural values on user acceptance of IT.
Based on a synthesis of technology acceptance and cultural theories, this study incorporates work related cultural values into Technology Acceptance Model (TAM). The four cultural values of individualism/collectivism, power distance, uncertainty avoidance, and masculinity/femininity identified by Hofstede are posited to either directly influence or to moderate user acceptance to email in the context of the PRC.
Data were collected from the banking industry in the PRC. Cultural values were measured at the individual level to avoid over generalizations of cultural typology and to remedy the inadequacy of post hoc explanation in conventional IS cultural studies. Instead of using the scores of national culture proposed by Hofstede’s cultural study in 1980, this study measures cultural values in terms of personal traits to reflect the changes in and the complexity of cultural values in face of a two-decades of societal change.
Structural equation models (SEMs) and moderated structural equation models (MSEMs) are used in the study to explore the direct impact and the moderating effect of cultural values. Confirmatory factor analysis and structural path analysis using LISREL were performed to analyze data collected.
The findings show that cultural values have both direct impact and moderation effect on user acceptance to email. The TAM general model was found to be applicable in the Chinese context. Collectivism was found to be an antecedent of Subjective Norms, while Masculinity has no significant influence on Perceived Usefulness. In addition, Power Distance was found to moderate the relationship between Subjective Norms and Intention to Use email; while Uncertainty Avoidance moderates the relationship between Perceived Ease of Use and Perceived Usefulness of email.
The findings are expected to provide insights that can help international businesses to enhance technology acceptance across national boundaries. An understanding of the relationship between cultural values and technology acceptance should help organizations understand the influence of core societal values on email acceptance and so to better utilize social and cultural practices in organizational technology diffusion. This study suggests a few guidelines for better utilizing computer mediated communication technology in regard to the cultural challenges
Detailed Facade Reconstruction for Mahattan-world Buildings
No full text3D building models play an important role in many real-world applications. Different models are suitable for different application scenarios based on their levels of detail. LOD3 models with facade details are crucial for many applications, such as virtual reality and urban simulation. Currently, 3D building models with lower LOD are largely available, but the number of LOD3 models is very limited. Most LOD3 reconstruction methods depend on manual operation, which is very time-consuming. How to automatically reconstruct the detailed facade for building models has remained a problem in computer vision. The problem can be seen as an image processing problem, but how to convert the 2D results into 3D smoothly should also be considered. In this project, we proposed a method to automatically reconstruct the detailed building models based on the Faster R-CNN. The method starts from a set of street view images, and the results are models with facade elements. A 3D point cloud can be extracted from the images using SfM and MVS, and the camera parameters can also be recovered. We take advantage of the high-quality facade images and parse the facades to detect their bounding boxes. The bounding boxes can match pretty well with the rectangular shape of the facade elements. The 2D facade elements can be added to the 3D building model based on the camera parameters. The process is very efficient and automatic. The regularity of the facade elements will be reserved, making the result more convincing. Our method includes four main steps: (1) coarse model reconstruction, (2) facade image selection and rectification, (3) facade element detection and regularization, and (4) detailed facade reconstruction. Experiment results show that our method can produce reliable building models with facade details for many different situations. It can work for both the multi-face building blocks and the street side buildings. Our test shows that the window detection performance is pretty good. The object detection is extremely fast, and the whole pipeline is lightweight and efficient. In theory, the method can also be extended to reconstruct large-scale city models, which means it has broad application prospects.Geomatic
Recommended from our members
Effects of scaling on microstructure evolution of Cu nanolines and impact on electromigration reliability
No full texttextScaling can significantly degrade the electromigration (EM) lifetime for Cu interconnects, raising serious reliability concerns. Different methods have emerged to enhance the EM resistance of Cu by suppressing the interface diffusion (the historically fastest diffusion path), notably using CoWP metal cap and Mn alloying. With further scaling of Cu interconnects, EM reliability becomes increasingly complex due to changes in Cu microstructure. In ultra-fine Cu lines a large population of small grains mix with bamboo-type grains, resulting in an additional contribution of grain boundary diffusion to EM degradation. With the interface diffusion suppressed by CoWP or Mn alloying, the grain structure effect becomes even more important. The objective of this study is to investigate the EM reliability of ultra-fine Cu interconnects, focusing on the scaling effect on grain structure and mass transport. First, the detailed microstructure information of Cu interconnects down to the 22 nm node was analyzed using a transmission electron microscope (TEM)-based high resolution diffraction technique. A dominant sidewall growth of {111} grains was observed for 70 nm Cu lines (45 nm node), reflecting the importance of interfacial energy in controlling grain growth. The strength of the {111} texture was found to significantly increase as line width was reduced to 40 nm (22 nm node), while the length fraction of coherent twin boundaries was reduced to ~1%. Secondly, the results from microstructure together with the deduced interfacial and grain boundary diffusivities were used to identify flux divergent sites for void formation and to analyze the grain structure effect on EM statistics using a microstructure-based kinetic model. Finally, based on the analysis of Cu grain structure evolution with downscaling, the scaling behavior of EM drift velocity was investigated for Cu interconnects with CoWP capping and Mn alloying. This enables us to project the EM lifetime and statistics for future technology nodes. The Mn alloying effect on mass transport in combination of grain structure control was found to provide an effective means to improve EM reliability especially with further scaling. In summary, this study establishes a correlation between the microstructure of Cu nanolines, void formation kinetics, and EM statistics.Mechanical Engineerin
Electrophysiological evidence of categorical perception of Chinese lexical tones in attentive condition
No full textPrevious electrophysiological evidence supports categorical perception of Chinese lexical tones at the preattentive stage (Xi and colleagues). In this study, we examined participants' attentive responses to tonal continua in an event-related potential experiment that recorded their N2b and P3b oddball responses. We found that for both the N2b and the P3b component, the responses elicited by the within-category deviants were similar in the left and the right recording sites. However, the across-category deviants elicited larger responses in the left recording sites than in the right sites, reflecting conscious phonological processing of lexical tones. These results provide electrophysiological correlates of categorical perception of Chinese lexical tones in later stages associated with controlled processes. NeuroReport 23: 35-39 (C) 2011 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins
Cortical Dynamics of Acoustic and Phonological Processing in Speech Perception
No full textIn speech perception, a functional hierarchy has been proposed by recent functional neuroimaging studies: Core auditory areas on the dorsal plane of superior temporal gyrus (STG) are sensitive to basic acoustic characteristics, whereas downstream regions, specifically the left superior temporal sulcus (STS) and middle temporal gyrus (MTG) ventral to Heschl's gyrus (HG) are responsive to abstract phonological features. What is unclear so far is the relationship between the dorsal and ventral processes, especially with regard to whether low-level acoustic processing is modulated by high-level phonological processing. To address the issue, we assessed sensitivity of core auditory and downstream regions to acoustic and phonological variations by using within-and across-category lexical tonal continua with equal physical intervals. We found that relative to within-category variation, across-category variation elicited stronger activation in the left middle MTG (mMTG), apparently reflecting the abstract phonological representations. At the same time, activation in the core auditory region decreased, resulting from the top-down influences of phonological processing. These results support a hierarchical organization of the ventral acoustic-phonological processing stream, which originates in the right HG/STG and projects to the left mMTG. Furthermore, our study provides direct evidence that low-level acoustic analysis is modulated by high-level phonological representations, revealing the cortical dynamics of acoustic and phonological processing in speech perception. Our findings confirm the existence of reciprocal progression projections in the auditory pathways and the roles of both feed-forward and feedback mechanisms in speech perception
Recommended from our members
A framework for natural disaster memorial park design 5/12 Earthquake Memorial Park design
No full textAn earthquake with a magnitude of 8.0 on the Richter scale rocked Sichuan on May 12, 2008, eventually claiming 69,227 lives, and 374,643 injured. The quake toppled houses and schools, virtually destroying entire villages, and irreparably changed everyone's world there. The quake severely affected an estimated 45,547,565 residents in Sichuan province, damaged approximately 4,300,000 structures, and destroyed buildings including homes, businesses, schools, and hospitals. Thousands of innocent people lost their precious lives in this disaster. Among these people, there were young students reading out beautiful poems in books; there were mamas preparing hot milk for their kids in the morning; there were...however, those bright lives, at that moment, all became cold numbers in the history books. A natural disaster memorial park is needed to memorialize all the survivors and victims of this great disaster, to tell stories of survival and loss, to encourage people surmounting the tragedy bravely, and to provide a refuge for future disasters. Throughout the research conducted after the May 12 earthquake, the author has observed that no integrated system of planning and design has been established in natural disaster memorial park design. The thesis defines the conception of a memorial landscape and natural disaster memorial park, reviews the history of natural disaster memorial parks, and sorts through many cases of memorial parks. A general design guideline and theory for natural disaster memorial park design will be summarized from case studies, and this guideline will be interpreted particularly in terms of the 5/12 Earthquake Memorial Park design in China. The result of this research is an extension of an overall knowledge base and a theory explaining the difference between "natural disaster memorials" and "war memorials" design and summarizing the basic elements that constitute the physical and psychological characteristics of natural disaster memorial park design. The 5/12 Earthquake Memorial design will be a new application of the integration of the new theory about Natural Disaster Memorial Landscape design and will provide guidance and reference for park planners and designers to promote multiple functions in memorial park design in the future
Research on the Influence Mechanism of Consumers\u27 Impulsive Buying under the Scenario of Public Welfare Live Streaming
No full textAs the most popular online shopping method at present, live streaming shopping has achieved remarkable results. Live streaming shopping has also been widely concerned and studied. However, few scholars have conducted empirical research on how to promote product sales in the context of public welfare live streaming. Based on the S-O-R theory, we analyze the impact mechanism of consumers\u27 impulse buying under the scenario of public welfare live streaming through questionnaires, aiming to provide marketing strategy suggestions for solving the problem of live streaming, product promotion. The results show promotion efforts and moral elevation positively affect consumers\u27 perceived value and impulsive buying intention, and the mediating effect of perceived value is significant. We enriche the research elements of impulse buying from live streaming commerce, promotes the integration of marketing disciplines and social sciences, and provide marketing strategy for solving the problem of products, which has certain theoretical and practical value
- …
