45 research outputs found
Automatically Generating a Video Based on User Provided Text Input
Visual stories are a popular format for online storytelling in many contexts. Visualizing text often helps a reader understand the story. There are tools that currently exist which can generate multimedia based on user input text. However, the generated media may not always match the text input and may include images that are diverse in style. This disclosure describes techniques that use generative artificial intelligence to automatically generate images, animation, and audio based on user input text and preferences. The generated assets are combined into a visual story that has a coherent visual theme and that can help viewers understand text-based content better
MODELING SOCIAL EFFECTS IN A CROWD-FUNDING COMMUNITY: A CASE OF PRO-SOCIAL LENDING BEHAVIOR PREDICTIONS ON KIVA.ORG
Master'sMASTER OF SCIENC
Quantized event-driven simulation for integrated energy systems with hybrid continuous-discrete dynamics
Effective simulation methods are becoming critically essential for the analysis of integrated energy systems (IESs) to reveal the interactions of multiple energy carriers. The incorporation of various energy technologies and numerous controllers make the IES a heterogeneous system, which poses new challenges to simulation methods. This paper focuses on the simulation of an IES with hybrid continuous-discrete properties and heterogeneous characteristics. First, a modified third-order quantized state system (MQSS3) method is proposed for the simulation of district heating systems (DHSs), in which quantized state system (QSS) and time-discretized integration are integrated to efficiently manage numerous discrete control actions. Second, an event-driven framework is established to integrate MQSS3 into the simulation of the electricity-heat integrated energy system (EH-IES). This framework enables the adoption of the most suitable models and algorithms for different systems to accommodate the heterogeneous properties of an IES. Case studies of an EH-IES with maximum 80% PV penetration and 210 buildings demonstrate that the dynamic interactions between the DHS and the power distribution network are accurately illustrated by the proposed simulation methods, in which MQSS3 indicates the highest simulation efficiency. It is also demonstrated in the simulation results that the flexibility from DHS can be utilized as demand-side resource to support the operation of power distribution network in aspects such as consuming the surplus PV generations
Data-driven coordinated voltage control method of distribution networks with high DG penetration
The highly penetrated distributed generators (DGs) aggravate the voltage violations in active distribution networks (ADNs). The coordination of various regulation devices such as on-load tap changers (OLTCs) and DG inverters can effectively address the voltage issues. Considering the problems of inaccurate network parameters and rapid DG fluctuation in practical operation, multi-source data can be utilized to establish the data-driven control model. In this paper, a data-driven coordinated voltage control method with the coordination of OLTC and DG inverters on multiple time-scales is proposed without relying on the accurate physical model. First, based on the multi-source data, a data-driven voltage control model is established. Multiple regulation devices such as OLTC and DG are coordinated on multiple time-scales to maintain voltages within the desired range. Then, a critical measurement selection method is proposed to guarantee the voltage control performance under the partial measurements in practical ADNs. Finally, the proposed method is validated on the modified IEEE 33-node and IEEE 123-node test cases. Case studies illustrate the effectiveness of the proposed method, as well as the adaptability to DG uncertainties
Asynchronous multi-rate method of real-time simulation for active distribution networks
The real-time simulation of active distribution networks (ADNs) can provide an accurate insight into transient behaviours, but faces challenges in simulation efficiency and flexibility brought by larger system scales and wider time-scale ranges. This paper presents an asynchronous multi-rate (AMR) method and design for the real-time simulation of large-scale ADNs. In the proposed method, the entire ADN was decoupled into different subsystems according to accuracy requirements, and optimized time-steps were allocated to each subsystem to realize a fully distributed simulation. This not only alleviated the time-step coordination problem existing in multi-rate real-time simulations, but also enhanced the flexible expansion capabilities of the real-time simulator. To realize the AMR real-time simulation, a multi-rate interfacing method, synchronization mechanism, and data communication strategy are proposed in this paper, and their hardware design is also presented in detail. A modified IEEE 123-node system with photovoltaics and wind turbine generators was simulated on a 3 field-programmable gate arrays (FPGAs)-based AMR real-time simulator. The real-time results were captured by the oscilloscope and verified with PSCAD/EMTDC, which demonstrated the superiority in simulation flexibility and accuracy compared with the synchronous multi-rate (SMR) method
Multi-stage supply restoration of active distribution networks with SOP integration
Supply restoration from outages is essential for improving the reliability of active distribution networks (ADNs) after fault isolation. Soft open point (SOP) can adjust the power flow among feeders and provide voltage support for power outage areas. Considering the sequential coordination of switching operation and SOP control mode selection, a multi-stage supply restoration method with SOPs is proposed for ADNs. First, the sequential energization is formulated, in which the impact of SOP control mode on restoration sequence is analyzed. By providing voltage support, the coordination of SOPs will rapidly energize the outage area and improve the voltage profile. Then, a multi-stage restoration model with SOPs is proposed, in which reconfiguration of switches and control mode selection of SOPs are coordinated in sequence to maximize the load recovery level of ADNs. Through the switching action-time mapping, secure operation is ensured during the entire supply restoration process. Finally, the effectiveness of the proposed method is validated on a modified IEEE 33-node distribution system and practical distribution networks with four-terminal SOP. Results show that the proposed method can fully exploit the potential benefits of SOPs and effectively enhance the load recovery level of ADNs
Why Do Users Abandon Online Social Network Sites? A Case Study of the Social Capital Paradox
Most studies on social network evolvement focus on the effect of structure aspects (e.g. social network size, degree, centrality etc.) of social network sites (SNSs), but fail to pay attention to SNS users’ behavior as a potentially influential factor (e.g. usage pattern, content flow). Many online social network sites have faded into oblivion not because of the lack of user base, but due to the inactivity of users online. This research adopts the case study approach to investigate why users eventually abandon SNSs. Users adopt SNSs mainly to gain social capital. However, as users gain more social capital, they may eventually experience a “backfire”, which we term the “social capital paradox”. Adopting the lens of expectation disconfirmation theory (EDT), we attempt to elucidate the mechanisms underlying the eventual abandonment of SNS
A sustainable strategy for remediation of oily sewage: Clean and safe
Sustainable and economically feasible treatment on oily sewage is of great significance. Herein, the benzoxazine monomer (C-fa) derived from renewable feedstock was facilely in-situ polymerized on the skeleton of melamine sponge (MS), accompanied with SiO2 nanoparticles (NPs). Due to the robust hydrophobicity of poly(C-fa) and the as constructed nano-micro hierarchical structure, the as-fabricated porous composite (PBZ-SiO2-MS) showed wide applicability in oily sewage remediation, including selective absorption of layered oil/water mixture, separation of surfactant stabilized W/O and O/W emulsion with ultrahigh separation efficiency (higher than 99.9%) and satisfactory permeation flux (1300 L-2 h(-1)). In addition, the remarkable flame retardancy of polybenzoxazine and MS, as well as its high absorption speed and capacity, endowed PBZ-SiO2-MSs with great ability to confine the flame range and prevent the potential explosion when spilled oil is ignited. This easy fabricated, low cost and versatile PBZ-SiO2-MSs illustrated an ingenious example of the integration of the high material performance and green chemistry concept
Facile synthesis of bio-based reactive flame retardant from vanillin and guaiacol for epoxy resin
With the purpose to obtain an eco-friendly flame retardant for epoxy resin, a facile method for the synthesis of a bio-based epoxy monomer containing DOPO units (DGEBDB) from lignin-derived vanillin and guaiacol, was presented in this work. During the synthesis process, guaiacol acted as both reactant and solvent. And it could be recycled in situ and re-used as the fresh one. In order to evaluate the flame retardancy of DGEBDB, it was mixed with diglycidyl ether of bisphenol A (DGEBA) and cured with 4,4-diaminodiphenylmethane (DDM). Results showed that, DGEBDB demonstrated a good compatibility with DGEBA, and the mechanical properties of cured resins were obviously improved with the addition of DGEBDB. As expected, the limiting oxygen index (LOI) of cured resin reached 30.2% with the content of phosphorus only 0.67 wt%, in which the weight ratio between DGEBDB and DGEBA was 1:9 (B1D9/DDM). When the weight ratio of DGEBDB to DGEBA was further increased to 2:8 for the B2D8/DDM system, the UL-94 V-0 grade was achieved. Meanwhile, the mechanism of DGEBDB in improving the flame retardancy of cured resin was discussed and revealed. This easily available and eco-friendly DGEBDB was proved to be a highly efficient reactive flame retardant for epoxy resin