We discuss the Dirac, Majorana, and Weyl fermion fields. The definitions and motivations for introducing each kind of field is discussed, along with the connections between them. It is pointed out ...that these definitions have to do with the proper Lorentz group and not with any discrete symmetry. The action of discrete symmetries, such as charge conjugation and CP on various types of fermion fields, which are particularly important for Majorana fermions, is also clarified.
This paper presents a novel approach to the coherency identification technique in interconnected power system using independent component analysis (ICA). The ICA is applied to the generator speed and ...bus angle data to identify the coherent areas of the system. The results of the application of ICA using simulated data from 16-machine 68-bus system model and on data gathered through U.K. University-based Wide-Area Measurement System are presented. The approach is able to identify the cluster of generators and buses following a disturbance in the system. It is also demonstrated that the approach is robust in the presence of noise in measured signal, which is an important factor to be considered for assessing the effectiveness of any measurement-based technique.
This paper presents the modal analysis of a grid-connected doubly fed induction generator (DFIG). The change in modal properties for different system parameters, operating points, and grid strengths ...are computed and observed. The results offer a better understanding of the DFIG intrinsic dynamics, which can also be useful for control design and model justification.
•Silicon-on-nitride slot waveguide-based evanescent field absorption-gas sensing scheme exploiting mid-IR fingerprint regime is proposed.•Numerical demonstration of the detection of NH3 gas in ...atmosphere operating at 3μm is analyzed.•With optimized waveguide structure, maximum achievable evanescent field fraction becomes ∼43%.•Feasible detection up to 5ppm level with a waveguide length of just 8.7mm.•Various fabrication tolerances are examined in detail and proposed structure has the potential for chip-scale trace gas sensing.
We propose design of a chip-scale evanescent field absorption-based trace gas sensor, exploiting silicon-on-nitride (SON) slot waveguide structure at mid-IR wavelength region. As an example, we numerically demonstrate detectability of NH3 gas in the atmosphere at its characteristic absorption wavelength of 3μm. Using the optimum sensor design, detection down to 5ppm including loss is viable in just ∼8.7mm length of the proposed slot waveguide. The achievable evanescent field fraction (η) is upto ∼43%. Our tolerance studies show that η is relatively more critical to the slot width as compared to its height.
In this study, a statistical framework is introduced to assess the suitability of various state estimation (SE) methodologies for the purpose of distribution system state estimation. The existing ...algorithms adopted in the transmission system SE are reconfigured for the distribution system. The performance of the three SE algorithms has been examined and discussed in standard 12-bus and 95-bus UK-GDS network models.
Hyperbilirubinemia is a common problem in neonates that can progress into kernicterus. Suspected neonatal hyperbilirubinemia is a common reason for contact with the healthcare system. The severity ...and management of jaundice are determined based on estimated bilirubin levels. However, no easy and accessible tool for self-assessing neonatal jaundice is currently available. Smartphones could potentially be transformed into a medical device that could be used by both patients and practitioners.
To investigate whether a digital image produced by a camera embedded on a smartphone can be a used as a screening tool for neonatal hyperbilirubinemia.
A total of 64 randomly selected newborns were enrolled. The inclusion criteria were healthy Caucasians, gestational age >35 weeks, age >24 hours and ≤14 days old, and parental informed consent. The exclusion criteria were facial skin lesions and light treatment. Images of the glabella were obtained with an iPhone 6 via i) directly applied pressure, ii) a dermatoscope, or iii) a dermatoscope equipped with a Wratten No. 11 filter. The red, green and blue colour intensities of each image were compared to bilirubin levels.
Only the dermatoscope-acquired intensities of the green and blue channels were significantly correlated (p < 0.001) with bilirubin measurements (Pearson's r: 0.59 and 0.48, respectively). For the green and blue channels, discrimination limits of 212 and 190, respectively, revealed a sensitivity and specificity of 100% and 62.5%, respectively, for green and 90.9% and 60%, respectively, for blue for a plasma bilirubin above 205 μmol/L.
The results of this study indicate that a smartphone equipped with a consistent light source in the form of a dermatoscope may be a simple screening tool for neonatal hyperbilirubinemia. However, the method requires some improvement before clinical application.
For nearly 20 years, the Test Feeder Working Group of the Distribution System Analysis Subcommittee has been developing openly available distribution test feeders for use by researchers. The purpose ...of these test feeders is to provide models of distribution systems that reflect the wide diversity in design and their various analytic challenges. Because of their utility and accessibility, the test feeders have been used for a wide range of research, some of which has been outside the original scope of intended uses. This paper provides an overview of the existing distribution feeder models and clarifies the specific analytic challenges that they were originally designed to examine. Additionally, this paper will provide guidance on which feeders are best suited for various types of analysis. The purpose of this paper is to provide the original intent of the Working Group and to provide the information necessary so that researchers may make an informed decision on which of the test feeders are most appropriate for their work.
Primary triple negative breast cancers (TNBC) are prone to dissemination but sub-clonal relationships between tumors and resulting metastases are poorly understood. Here we use cellular barcoding of ...two treatment-naïve TNBC patient-derived xenografts (PDXs) to track the spatio-temporal fate of thousands of barcoded clones in primary tumors, and their metastases. Tumor resection had a major impact on reducing clonal diversity in secondary sites, indicating that most disseminated tumor cells lacked the capacity to 'seed', hence originated from 'shedders' that did not persist. The few clones that continued to grow after resection i.e. 'seeders', did not correlate in frequency with their parental clones in primary tumors. Cisplatin treatment of one BRCA1-mutated PDX model to non-palpable levels had a surprisingly minor impact on clonal diversity in the relapsed tumor yet purged 50% of distal clones. Therefore, clonal features of shedding, seeding and drug resistance are important factors to consider for the design of therapeutic strategies.
A stochastic model of wind generation in an optimal power flow (OPF) dispatching program is presented. The model includes the error in wind power forecasts using a probability or relative frequency ...histogram. Compared with the deterministic OPF, the proposed model allows the coordination of wind and thermal power while accounting for the expected penalty cost for not using all available wind power and the expected cost of calling up the power reserves because of wind power shortage. The stochastic model is integrated in an extended conic quadratic OPF program in which wind driven generators are represented as induction machines. The simulation results are presented for cases where the forecasting error histogram is either derived from historical data or estimated by a bimodal normal distribution. The effect of the skewness of the error distribution on the optimal dispatch policy is studied.
This study presents, an approach to utilise the loads as pseudo-measurements for the purpose of distribution system state estimation. The load probability density function (pdf) in the distribution ...network shows a number of variations at different nodes and cannot be represented by any specific distribution. The approach presented in this study, represents all the load pdfs through the Gaussian mixture model. The expectation maximisation algorithm is used to obtain the parameters of the mixture components. The standard weighted least squares (WLS) algorithm utilises these load models as pseudo-measurements. The effectiveness of WLS is assessed through some statistical measures, such as bias, consistency and quality of the estimates in a 95-bus generic distribution network model.
PDF
