Buildings-to-Grid Integration Framework

This paper puts forth a mathematical framework for Buildings-to-Grid (BtG) integration in smart cities. The framework explicitly couples power grid and building's control actions and operational decisions, and can be utilized by buildings and power grids operators to simultaneously optimize their performance. Simplified dynamics of building clusters and building-integrated power networks with algebraic equations are presented---both operating at different time-scales. A model predictive control (MPC)-based algorithm that formulates the BtG integration and accounts for the time-scale discrepancy is developed. The formulation captures dynamic and algebraic power flow constraints of power networks and is shown to be numerically advantageous. The paper analytically establishes that the BtG integration yields a reduced total system cost in comparison with decoupled designs where grid and building operators determine their controls separately. The developed framework is tested on standard power networks that include thousands of buildings modeled using industrial data. Case studies demonstrate building energy savings and significant frequency regulation, while these findings carry over in network simulations with nonlinear power flows and mismatch in building model parameters. Finally, simulations indicate that the performance does not significantly worsen when there is uncertainty in the forecasted weather and base load conditions.Comment: In Press, IEEE Transactions on Smart Gri

Occupant Behavior Driven Buildings-to-grid Integration Framework for Large Commercial Buildings

This paper proposes and develops an occupancy-based control and optimization framework for reducing energy consumption and cost within the context of Buildings-to-Grid (BtG) integration. A mathematical framework of large-scale integration, control and optimization of solar powered buildings with battery energy storage system and the grid is proposed and demonstrated. Building MPC formulations are designed based on appropriately linearized large commercial building conditioning and battery system models. A high-level linearized grid distribution network is also developed via IEEE standard grid systems with 9, 14, and 30 buses. The final decentralized utility-scale BtG integrations with battery storages, photovoltaics generations, different grid systems, building occupancy simulators, and building HVAC system are conceptually designed and simulated. The results show that the integrated system can save up to 40% to 46% amount of energy/costs from building side and 90% amount of operation costs from grid side

A Probabilistic Framework To Diagnose Faults in Air Handling Units.

Air handling unit (AHU) is one of the most extensively used equipment in large commercial buildings. This device is typically customized and lacks quality system integration, which can result in, hardwire failures and controller errors. Air handling unit Performance Assessment Rules (APAR) is a fault detection tool that uses a set of expert rules derived from mass and energy balances to detect faults in air handling units. Although APAR has many advantages over other methods, for example, no training data required and easy to implement commercially, most of the time it is unable to provide the diagnosis of the faults. There is no established way to have the correct diagnosis for rule based fault detection system. In this study, we developed a new way to detect and diagnose faults in AHU through combining APAR rules and Bayesian Belief Network. BBN is used as a decision support tool for rule-based expert system. BBN is highly capable to prioritize faults when multiple rules are satisfied simultaneously. The proposed model tested with real time measured data of a campus building at University of Texas at San Antonio (UTSA)

Removal of point source leakage from time-order data filtering

Time-ordered data (TOD) from ground-based CMB experiments are generally filtered before map-making to remove or reduce the contamination from the ground and the atmospheric emissions. However, when the observation region contains strong point sources, the filtering process will result in considerable leakage around the point sources in a measured CMB map, and leave spurious polarization signals. Therefore, such signals need to be assessed and removed before CMB science exploitation. In this work, we present a new method that we call "template fitting" and can effectively remove these leakage signals in pixel domain, not only satisfying the requirement for measuring primordial gravitational waves from CMB-$B$ modes, but also avoiding time-consuming operations on TOD.Comment: 13pages, 6 figures, 5 table

Development and validation of a nomogram to predict the five-year risk of revascularization for non-culprit lesion progression in STEMI patients after primary PCI

BackgroundAcute ST-segment elevation myocardial infarction (STEMI) patients after primary PCI were readmitted for revascularization due to non-culprit lesion (NCL) progression.ObjectiveTo develop and validate a nomogram that can accurately predict the likelihood of NCL progression revascularization in STEMI patients following primary PCI.MethodsThe study enrolled 1,612 STEMI patients after primary PCI in our hospital from June 2009 to June 2018. Patients were randomly divided into training and validation sets in a 7:3 ratio. The independent risk factors were determined by LASSO regression and multivariable logistic regression analysis. Multivariate logistic regression analysis was utilized to develop a nomogram, which was then evaluated for its performance using the concordance statistics, calibration plots, and decision curve analysis (DCA).ResultsThe nomogram was composed of five predictors, including age (OR: 1.007 95% CI: 1.005–1.009, P < 0.001), body mass index (OR: 1.476, 95% CI: 1.363–1.600, P < 0.001), triglyceride and glucose index (OR: 1.050, 95% CI: 1.022–1.079, P < 0.001), Killip classification (OR: 1.594, 95% CI: 1.140–2.229, P = 0.006), and serum creatinine (OR: 1.007, 95% CI: 1.005–1.009, P < 0.001). Both the training and validation groups accurately predicted the occurrence of NCL progression revascularization (The area under the receiver operating characteristic curve values, 0.901 and 0.857). The calibration plots indicated an excellent agreement between prediction and observation in both sets. Furthermore, the DCA demonstrated that the model exhibited clinical efficacy.ConclusionA convenient and accurate nomogram was developed and validated for predicting the occurrence of NCL progression revascularization in STEMI patients after primary PCI

Tower crane design and simulation

Since the inception of Tower crane in 1949 in Germany by Hans Liebherr, its developments had been rapid. Tower cranes are now essential in construction industry, responsible for lifting, moving and lowering objects[1]. The aim of this project was to ensure effective and good productivity in the construction of HDB estates. The three objectives presented in this project were (1) design Yong Mao’s STT153 tower crane 3D model, (2) simulate the completed model into the simulator successfully, and, (3) validate the completed model with reference to other simulators, as well as, design considerations for reconfiguration. Autodesk® 3DS Max® software was selected as the ideal tool with its advantageous properties of modelling and surface type. Components of the tower crane were designed individually and consisted of the base, the boom, horizontal jib, sling hook, cabin and counterweights. Care was taken in ensuring a consistent naming convention between software and the system required by the simulator. Simulation was carried out in an in-house simulator designed by NTU researchers and PhD students. The simulator required the input of robotic crane, point cloud for modelling the environment and requirements for the lift path. The tower crane model was successfully imported into the software. Validation was then made to ensure compatibility of results between in-house software and those used in industry. In addition, design considerations for reconfiguration was also included. Despite many challenges, the author successfully created the tower crane model and imported it into the simulator software. The compatibility of this simulator allowed for realistic lift planning and ensuring safe practices in construction industry. The primary objective was met, with a big leap into improving productivity in HDB construction. Moving forward, the ability to integrate this in-house simulator with external industrial platforms for large scale projects will open paths for future studies in Smart Cranes industries.Bachelor of Engineering (Mechanical Engineering

Spatio-Temporal Neural Dynamics of Observing Non-Tool Manipulable Objects and Interactions

Previous studies have reported that a series of sensory–motor-related cortical areas are affected when a healthy human is presented with images of tools. This phenomenon has been explained as familiar tools launching a memory-retrieval process to provide a basis for using the tools. Consequently, we postulated that this theory may also be applicable if images of tools were replaced with images of daily objects if they are graspable (i.e., manipulable). Therefore, we designed and ran experiments with human volunteers (participants) who were visually presented with images of three different daily objects and recorded their electroencephalography (EEG) synchronously. Additionally, images of these objects being grasped by human hands were presented to the participants. Dynamic functional connectivity between the visual cortex and all the other areas of the brain was estimated to find which of them were influenced by visual stimuli. Next, we compared our results with those of previous studies that investigated brain response when participants looked at tools and concluded that manipulable objects caused similar cerebral activity to tools. We also looked into mu rhythm and found that looking at a manipulable object did not elicit a similar activity to seeing the same object being grasped

Impact of COVID-19 on Male and Female Employment in Sweden

The study investigates the impact of Covid-19 on employment in Sweden, it focuses on how men and women have been affected during the pandemic. Despite Sweden being one of the top countries in terms of gender equality, we want to see if the effects of the crisis differ for each of them, and to help us with our research we will go through different industries in the Swedish labor market to examine the impact on men and female workers in those industries during the pandemic.The results show that Female workers in Sweden have been more negatively impacted during COVID-19 than men, also we find out that the employment situation of men and women may also have different effects within the same industr

Impact of COVID-19 on Male and Female Employment in Sweden

The study investigates the impact of Covid-19 on employment in Sweden, it focuses on how men and women have been affected during the pandemic. Despite Sweden being one of the top countries in terms of gender equality, we want to see if the effects of the crisis differ for each of them, and to help us with our research we will go through different industries in the Swedish labor market to examine the impact on men and female workers in those industries during the pandemic.The results show that Female workers in Sweden have been more negatively impacted during COVID-19 than men, also we find out that the employment situation of men and women may also have different effects within the same industr