Uncertainty Analysis of the Adequacy Assessment Model of a Distributed Generation System

Due to the inherent aleatory uncertainties in renewable generators, the reliability/adequacy assessments of distributed generation (DG) systems have been particularly focused on the probabilistic modeling of random behaviors, given sufficient informative data. However, another type of uncertainty (epistemic uncertainty) must be accounted for in the modeling, due to incomplete knowledge of the phenomena and imprecise evaluation of the related characteristic parameters. In circumstances of few informative data, this type of uncertainty calls for alternative methods of representation, propagation, analysis and interpretation. In this study, we make a first attempt to identify, model, and jointly propagate aleatory and epistemic uncertainties in the context of DG systems modeling for adequacy assessment. Probability and possibility distributions are used to model the aleatory and epistemic uncertainties, respectively. Evidence theory is used to incorporate the two uncertainties under a single framework. Based on the plausibility and belief functions of evidence theory, the hybrid propagation approach is introduced. A demonstration is given on a DG system adapted from the IEEE 34 nodes distribution test feeder. Compared to the pure probabilistic approach, it is shown that the hybrid propagation is capable of explicitly expressing the imprecision in the knowledge on the DG parameters into the final adequacy values assessed. It also effectively captures the growth of uncertainties with higher DG penetration levels

Driving Forces on China's Circular Economy: From Government's perspectives

AbstractIt is a general trend that China's economy is facing a major adjustment of circular economy. Although China's economic development in the past 30 years is very fast, it is mainly driven by exports and investment. At present, there are some problems with China's transformation and upgrade of the industrial structure. The main cause for these problems is the lack of driving forces for the developing circular economy. However, the act of government and the corresponding driving mechanism should play a decisive role. Therefore, we should adjust the government behavior pattern in developing the Circular Economy, so as to contribute to the sustainable development of China's economy

Improvement and implementation of analog based method for software project cost estimation

Ph.DDOCTOR OF PHILOSOPH

Dynamic Reliability Models for Multiple Dependent Competing Degradation Processes

International audienceThis paper presents a holistic treatment to multiple dependent competing degradation processes, by employing the piecewise-deterministic Markov process (PDMP) modeling framework. The proposed method can handle the dependencies between physics-based models, between multi-state models and between these two types of models. A Monte Carlo simulation algorithm is developed to compute the components/systems reliability. A case study on one subsystem of the residual heat removal system (RHRS) of a nuclear power plant is illustrated

Multi-dimensional vibration sensing and simultaneous self-homodyne optical transmission of single wavelength net 5.36 Tb/s signal using telecom 7-core fiber

We present a high-capacity self-homodyne optical transmission system that enables simultaneously multidimensional vibration sensing based on a weakly-coupled 7-core fiber. To our knowledge, we demonstrate for the first-time detection of fiber vibration direction along with strength, frequency, and location of the vibration source, while transmitting in the meantime single-carrier 16 QAM signal reaching a net date rate of 5.36 Tb/s over 41.4 km of telecom 7-core fiber.Comment: 5 pages, 4 figure

Reliability of listed companies' value estimates and target prices: evidence from industry-based combined valuation models

The low reliability of listed companies' target prices is a major issue globally. As the foundation of the target price, the value estimate is important in the determination of target price reliability. The value estimate is the estimated intrinsic value of a company produced by the company valuation model. However, there is no individual valuation model capable of fully disclosing the intrinsic value, and the use of more than one valuation model simultaneously is a common practice. In addition, it is important for the valuation model to be consistent with the characteristics of the company. However, the existing literature offers little guidance on this valuation issue, especially on how to appropriately construct a combined valuation model based on the characteristics of the company. This study investigates the underlying reasons for the low reliability of listed companies' value estimates and target prices, and attempts to improve their reliability via the enhanced company valuation method. In particular, the study focuses on the industry based combined valuation models and their application to the valuations of listed companies from different industries. The study begins with the estimation of discount rate for each selected firm, and then applies the industry based individual and combined models to generate value estimates for each firm, followed by the target price setting process to determine the most reasonable target price. The improved reliability test techniques will be used to measure the performance of value estimates, target prices and the financial analysts' target prices, so that the best individual and combined valuation models for different industries can be identified. This study has produced several important findings. The results show that the reliability of the target price is determined by the value estimate and the target price setting process. The reliability of the value estimate is influenced by the data and valuation method. The results also show that absolute valuation models have significant advantages in emerging industries such as biotechnology. The relative valuation models exhibit good performance in the traditional industries such as technology hardware. The forward valuation models are suitable for stable industries such as insurance with accurate forecasts. The trailing valuation models have apparent advantages in unstable industries such as securities with great uncertainty. The results also show that the combined valuation models have significant advantages over the individual valuation models. The mixed combined valuation models are preferred in practice

MODELING MULTIPLE DEPENDENT COMPETING DEGRADATIONS UNDER EPISTEMIC UNCERTAINTY VIA PDMP

International audiencePiecewise-deterministic Markov process (PDMP) modeling framework can handle the dependencies between physics-based models, between multi-state models and between these two types of models. Epistemic uncertainty can arise due to the incomplete or imprecise knowledge about the degradation processes and the governing parameters: to take into account this, we describe the parameters of the PDMP model as fuzzy numbers. In this paper, we extend the finite-volume (FV) method to quantify the (fuzzy) reliability of the system. The proposed method is tested on one subsystem of the residual heat removal system (RHRS) of a nuclear power plant, and a comparison is offered with a Monte Carlo (MC) simulation solution