35 research outputs found
DETERMINING THE RELATIONSHIPS AMONG AIRPORT OPERATIONAL PERFORMANCE AREAS AND OTHER AIRPORT CHARACTERISTICS
In this thesis, a methodology is proposed to investigate pair-wise relationships between different types of airport operational performance variables. The methodology represents a fundamental contribution for comparing airport performance between different air traffic management systems. Considerable attention is paid to analyzing the most appropriate techniques in an effort to produce the most reliable results. Additionally, a method to display the results in a simple and clear way is also suggested to allow users to understand the results visually. The key variables obtained from the proposed methodology not only serve as building blocks for developing models to answer a variety of air traffic questions, which allow policy makers to make decisions on allocating resources wisely, but also can be used as an evaluation tool to assist the FAA in selecting candidate projects
Propagating Uncertainty in Solar Panel Performance for Life Cycle Modeling in Early Stage Design
One of the challenges in accurately applying metrics for life
cycle assessment lies in accounting for both irreducible and
inherent uncertainties in how a design will perform under
real world conditions. This paper presents a preliminary
study that compares two strategies, one simulation-based
and one set-based, for propagating uncertainty in a system.
These strategies for uncertainty propagation are then
aggregated. This work is conducted in the context of an
amorphous photovoltaic (PV) panel, using data gathered
from the National Solar Radiation Database, as well as
realistic data collected from an experimental hardware setup
specifically for this study. Results show that the influence of
various sources of uncertainty can vary widely, and in
particular that solar radiation intensity is a more significant
source of uncertainty than the efficiency of a PV panel. This
work also shows both set-based and simulation-based
approaches have limitations and must be applied
thoughtfully to prevent unrealistic results. Finally, it was
found that aggregation of the two uncertainty propagation
methods provided faster results than either method alone.Center for Scalable and Integrated NanomanufacturingNational Science Foundation (U.S.) (Nanoscale Science and Engineering Center
Automated Discovery of Flight Track Anomalies
As new technologies are developed to handle the complexities of the Next Generation Air Transportation System (NextGen), it is increasingly important to address both current and future safety concerns along with the operational, environmental, and efficiency issues within the National Airspace System (NAS). In recent years, the Federal Aviation Administrations (FAA) safety offices have been researching ways to utilize the many safety databases maintained by the FAA, such as those involving flight recorders, radar tracks, weather, and many other high- volume sensors, in order to monitor this unique and complex system. Although a number of current technologies do monitor the frequency of known safety risks in the NAS, very few methods currently exist that are capable of analyzing large data repositories with the purpose of discovering new and previously unmonitored safety risks. While monitoring the frequency of known events in the NAS enables mitigation of already identified problems, a more proactive approach of finding unidentified issues still needs to be addressed. This is especially important in the proactive identification of new, emergent safety issues that may result from the planned introduction of advanced NextGen air traffic management technologies and procedures. Development of an automated tool that continuously evaluates the NAS to discover both events exhibiting flight characteristics indicative of safety-related concerns as well as operational anomalies will heighten the awareness of such situations in the aviation community and serve to increase the overall safety of the NAS. This paper discusses the extension of previous anomaly detection work to identify operationally significant flights within the highly complex airspace encompassing the New York area of operations, focusing on the major airports of Newark International (EWR), LaGuardia International (LGA), and John F. Kennedy International (JFK). In addition, flight traffic in the vicinity of Denver International (DEN) airport/airspace is also investigated to evaluate the impact on operations due to variances in seasonal weather and airport elevation. From our previous research, subject matter experts determined that some of the identified anomalies were significant, but could not reach conclusive findings without additional supportive data. To advance this research further, causal examination using domain experts is continued along with the integration of air traffic control (ATC) voice data to shed much needed insight into resolving which flight characteristic(s) may be impacting an aircraft's unusual profile. Once a flight characteristic is identified, it could be included in a list of potential safety precursors. This paper also describes a process that has been developed and implemented to automatically identify and produce daily reports on flights of interest from the previous day
Weak temperature dependence of P (+) H A (-) recombination in mutant Rhodobacter sphaeroides reaction centers
International audienceIn contrast with findings on the wild-type Rhodobacter sphaeroides reaction center, biexponential P (+) H A (-) → PH A charge recombination is shown to be weakly dependent on temperature between 78 and 298 K in three variants with single amino acids exchanged in the vicinity of primary electron acceptors. These mutated reaction centers have diverse overall kinetics of charge recombination, spanning an average lifetime from ~2 to ~20 ns. Despite these differences a protein relaxation model applied previously to wild-type reaction centers was successfully used to relate the observed kinetics to the temporal evolution of the free energy level of the state P (+) H A (-) relative to P (+) B A (-) . We conclude that the observed variety in the kinetics of charge recombination, together with their weak temperature dependence, is caused by a combination of factors that are each affected to a different extent by the point mutations in a particular mutant complex. These are as follows: (1) the initial free energy gap between the states P (+) B A (-) and P (+) H A (-) , (2) the intrinsic rate of P (+) B A (-) → PB A charge recombination, and (3) the rate of protein relaxation in response to the appearance of the charge separated states. In the case of a mutant which displays rapid P (+) H A (-) recombination (ELL), most of this recombination occurs in an unrelaxed protein in which P (+) B A (-) and P (+) H A (-) are almost isoenergetic. In contrast, in a mutant in which P (+) H A (-) recombination is relatively slow (GML), most of the recombination occurs in a relaxed protein in which P (+) H A (-) is much lower in energy than P (+) H A (-) . The weak temperature dependence in the ELL reaction center and a YLH mutant was modeled in two ways: (1) by assuming that the initial P (+) B A (-) and P (+) H A (-) states in an unrelaxed protein are isoenergetic, whereas the final free energy gap between these states following the protein relaxation is large (~250 meV or more), independent of temperature and (2) by assuming that the initial and final free energy gaps between P (+) B A (-) and P (+) H A (-) are moderate and temperature dependent. In the case of the GML mutant, it was concluded that the free energy gap between P (+) B A (-) and P (+) H A (-) is large at all times
Determining the Relationships Among Airport Operational Performance Areas and Other Airport Characteristics
In this paper, a methodology is proposed to investigate pair-wise relationships between different types of airport operational performance variables. Having a better understanding of these relationships poses a fundamental contribution for investigating the pros and cons of air transportation systems in different countries. Considerable attention is paid to analyzing the most appropriate techniques in an effort to produce the most reliable results. Additionally, a method to display the results in a simple and clear way is also suggested to allow users to understand the results visually. The key variables obtained from the proposed methodology serve as building blocks for model development to answer a variety of air traffic questions, which allow policy makers to make decisions on allocating resources wisely
An analysis of the dual police inspector recruitment system of the Hong Kong Police Force
published_or_final_versionPublic AdministrationMasterMaster of Public Administratio
Kindergarten: a new mode of education for children
published_or_final_versionArchitectureMasterMaster of Architectur
Effects of virtual reality on anxiety and pain in adult patients undergoing wound-closure procedures: A pilot randomized controlled trial
Background In emergency departments, suturing is a typical procedure for closing lacerated wounds but is invasive and often causes anxiety and pain. Virtual reality (VR) intervention has been reported as a relaxing measure. Objective The study aims to examine the effects of VR intervention on anxiety, pain, physiological parameters, local anesthesia requirements and satisfaction in Chinese adult patients undergoing wound closure in emergency departments in Hong Kong. Methods Adult patients who had lacerated wounds and were undergoing wound closure by suturing can communicate in Chinese and were hemodynamically stable were invited for this trial. Eighty patients were randomly assigned to the VR group, which received VR intervention and standard care, or to the control group, which received standard care only. The primary outcome was anxiety, and the secondary outcomes included pain, blood pressure, pulse rate, satisfactory with pain management, service satisfactory, and extra local analgesia requirement. Outcomes were conducted at baseline, during the procedure and 5 min after the procedure. Results The VR group had a significantly greater reduction in anxiety ( p < 0.001), pain ( p < 0.001), systolic blood pressure ( p < 0.001), diastolic blood pressure ( p < 0.001), pulse rate ( p = 0.003) and requested less amount of additional local anesthesia ( p = 0.025). The satisfactory level with pain management ( p = 0.019) and service ( p = 0.002) were significantly higher in participants who received VR intervention. In addition, most participants preferred to have VR in the future, and no major adverse events associated with the use of VR were reported. Conclusion This pilot study provides insight into the use of VR and the direction of future studies. It may effectively improve psychological and physiological outcomes in adult patients during wound-closure procedures in emergency departments