The joint effect of mixed land uses and rainfall event types was studied using a two-year field monitoring program in four urban catchments in Calgary, Alberta, Canada. Event mean concentration (EMC) ...and event pollutant load (EPL) were employed to evaluate the total suspended sediment (TSS), nitrogen and phosphorus. The correlation analysis showed that most nitrogen and phosphorus components (except for NO2−/NO3− and TDP) predominantly exist in particulate form in the study areas. The correlation for EPL was notably stronger than EMC, which can be attributed to varying rainfall characteristics. The differences in EMCs and EPLs of TSS, nitrogen and phosphorus across catchments indicated that the complexity and spatial distribution of mixed land use can influence the generation and transportation of pollutants in urban runoff. The impacts of rainfall characteristics on stormwater quality are integrated rather than driven by a single rainfall characteristic. Brief but intense events tended to elevate TSS, nitrogen and phosphorus concentrations, especially in complex land-use catchments. Events with long antecedent dry days and short duration also resulted in increased pollutant concentrations, while events with long duration and low intensity could result in higher EPLs. The effect of mixed land use on water quality can vary depending on rainfall event types. Seasonal variations were found in EMC and EPL of TSS, nitrogen and phosphorus, with higher values in the spring and summer than the fall. Seasonal variations are mainly influenced by rainfall conditions, temperature and anthropogenic activities (e.g. lawn fertilization and de-icing with sands). MLR considering rainfall characteristics is an effective method for predicting stormwater quality within a single catchment. Considering complexity and spatial distribution of mixed land use can improve the accuracy of the harmonized MLR model. This research provided insights into understanding the complexities introduced by mixed land use and rainfall event types in urban stormwater quality.
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•Joint effects of mixed land uses and rainfall types on water quality were studied.•Spatial distribution of mixed land uses can affect the transportation of pollutants.•Brief but intense events tended to elevate TSS and nutrients concentrations.•Higher values of EMC and EPL were found in the spring and summer than the fall.•Considering effects of mixed land use can improve the accuracy of MLR model.
•This paper illustrates an application of the ISA methodology to quantify the risk reduction by means of FLEX and usual recovery strategies.•The impact of portable equipment and AFW recovery ...strategies on Damage Exceedance Frequency of TLFW sequences has been evaluated, as well as the RCP trip and F&B start time.•The FLEX strategies lead to a significant risk reduction in TLFW sequences.•The installation time of portable equipment is a key factor for FLEX strategies success.
After the accident at Fukushima Dai-ichi, considerable efforts were put on enhancing the capability of the Nuclear Power Plants to cope with conditions resulting from the loss of plant safety-related systems. The most widespread solution adopted worldwide has been to define and implement new procedures and emergency actuation plans, the so called FLEX strategies. Among these strategies, there are several recovery strategies which involve the use of portable equipment for accomplishing the safety functions of the unavailable systems. In some cases, these strategies have been devised to be performed concurrently to the usual system recovery procedures included in the EOPs of most NPPs. In this regard, the heat sink recovery after the occurrence of a Total Loss of Feedwater (TLFW) in a Westinghouse 3-loop PWR design is a significant example, and it has been chosen in the present study to assess the quantitative risk reduction provided by the usual and FLEX recovery strategies in a Westinghouse 3-loop PWR design. With this aim, the Integrated Safety Assessment (ISA) methodology, developed by the Spanish Nuclear Safety Council (CSN), has been applied to TLFW sequences as part of the collaboration between Technical University of Madrid (UPM), NFQ Solutions and CSN.
The efficient utilization of computation and communication resources became a critical design issue in a wide range of networked systems due to the finite computation and processing capabilities of ...system components (e.g., sensor, controller) and shared network bandwidth. Event-triggered mechanisms (ETMs) are regarded as a major paradigm shift in resource-constrained applications compared to the classical time-triggered mechanisms, which allows a trade-off to be achieved between desired control/estimation performance and improved resource efficiency. In recent years, dynamic event-triggered mechanisms (DETMs) are emerging as a promising enabler to fulfill more resource-efficient and flexible design requirements. This paper provides a comprehensive review of the latest developments in dynamic event-triggered control and estimation for networked systems. Firstly, a unified event-triggered control and estimation framework is established, which empowers several fundamental issues associated with the construction and implementation of the desired ETM and controller/estimator to be systematically investigated. Secondly, the motivations of DETMs and their main features and benefits are outlined. Then, two typical classes of DETMs based on auxiliary dynamic variables (ADVs) and dynamic threshold parameters (DTPs) are elaborated. In addition, the main techniques of constructing ADVs and DTPs are classified, and their corresponding analysis and design methods are discussed. Furthermore, three application examples are provided to evaluate different ETMs and verify how and under what conditions DETMs are superior to their static and periodic counterparts. Finally, several challenging issues are envisioned to direct the future research.
Supervisory control of fuzzy discrete event systems under partial observation is investigated in the paper. Without loss of generality, we consider fuzzy discrete event systems with constraints where ...a fuzzy discrete event system is modeled by a fuzzy automaton. Sequences of events that can be generated by the system are regarded as constraints and are modeled by a crisp automaton. A supervisor is designed to control the fuzzy discrete event system so that the supervised system is prevented from entering a pre-specified set of illegal/unsafe fuzzy states. A necessary and sufficient condition for the existence of a supervisor is obtained. When the condition is satisfied, an online supervisor can be designed. Fuzzy state estimation problem is first solved, as the supervisor is fuzzy-state-estimate-based. A method is developed to estimate fuzzy state iteratively after observation of each new event. We show that the supervisor so developed ensures the safety of the system and is least restrictive among all possible safe supervisors. Potential of the theoretical results for real-world applications is illustrated through an example of HIV/AIDS treatment decision-making.
Integration-technology feature shrink increases computing-system susceptibility to single-event effects (SEE). While modeling SEE faults will be critical, an integrated processor's scope makes ...physically correct modeling computationally intractable. Without useful models, presilicon evaluation of fault-tolerance approaches becomes impossible. To incorporate accurate transistor-level effects at a system scope, we present a multiscale simulation framework. Charge collection at the 1) device level determines 2) circuit-level transient duration and state-upset likelihood. Circuit effects, in turn, impact 3) register-transfer-level architecture-state corruption visible at 4) the system level. Thus, the physically accurate effects of SEEs in large-scale systems, executed on a high-performance computing (HPC) simulator, could be used to drive cross-layer radiation hardening by design. We demonstrate the capabilities of this model with two case studies. First, we determine a D flip-flop's sensitivity at the transistor level on 14-nm FinFet technology, validating the model against published cross sections. Second, we track and estimate faults in a microprocessor without interlocked pipelined stages (MIPS) processor for Adams 90% worst case environment in an isotropic space environment.
Research on major life events and personality change often focuses on the occurrence of specific life events such as childbirth, unemployment, or divorce. However, this typical approach has three ...important limitations: (1) Life events are typically measured categorically, (2) it is often assumed that people experience and change from the same event in the same way, and (3) external ratings of life events have unknown levels of validity. To address these limitations, we examined how common life events are typically perceived, how much perceptions of life events vary within events, and how well external ratings of events correspond to subjective ratings from people who experienced the events. We analyzed ratings of nine psychologically relevant characteristics of 10 common major life events from three different types of raters (N = 2,210). Each life event had a distinct subjectively rated profile that corresponded well to external ratings. Collectively, this study demonstrates that life events can be meaningfully described and differentiated with event characteristics. However, people’s individual perceptions of life events varied considerably even within events. Therefore, research on major life events and their associations with personality change should incorporate individual perceptions of the events to advance the understanding of these associations.
This document describes the radiation environments, physical mechanisms, and test philosophies that underpin radiation hardness assurance test methodologies. The natural space radiation environment ...is presented, including the contributions of both trapped and transient particles. The effects of shielding on radiation environments are briefly discussed. Laboratory radiation sources used to simulate radiation environments are covered, including how to choose appropriate sources to mimic environments of interest. The fundamental interactions of radiation with materials via direct and indirect ionization are summarized. Some general test considerations are covered, followed by in-depth discussions of physical mechanisms and issues for total dose and single-event effects testing. The purpose of this document is to describe why the test protocols we use are constructed the way they are. In other words, to answer the question: "Why do we test it that way"?
A burgeoning body of research has examined the influence of stable attributes of individuals, teams, and organizations on employee creativity. Events, however, permeate the increasingly dynamic and ...uncertain business context. To extend the creativity literature, we draw on event system theory to examine whether, when, and how workplace events impact employee creativity. Our findings based on two time‐lagged field studies reveal that workplace event novelty and criticality interact to fuel employee improvisation and in turn, employee creativity. The positive relationship between workplace event novelty and employee improvisation is stronger when workplace events are more critical. Our research highlights the value of an event‐oriented theory‐building approach to investigate dynamic organizational phenomena.
This article aims to provide a survey of modeling and simulation of single-event effects (SEEs) in digital electronics at device, circuit, and system levels. It primarily focuses on the specific ...multiscale, multiphysics, multidomain nature of SEEs and on the main underlying physical mechanisms that lead to the occurrence of single events in digital devices and circuits. This article addresses different ways to model and simulate both in space and time this complex sequence of mechanisms from the particle-material interaction up to the electrical response of a given electronics device, circuit, or system. It highlights the specific features of each methodology and discusses simulation requirements, code, or model inputs and expected outputs.
The proliferation of Phasor Measurement Units (PMUs) to monitor power grid dynamics at a high resolution (10-100 samples/sec) has opened a new paradigm to situational awareness. Existing event ...detection techniques for identifying multiple events like transmission line faults, generation trip, line trip, load loss, current transformer (CT) failure, islanding, etc., are prone to misdetection, delayed detection, and false detection. Moreover, most of them can detect events either with fast (transient events) or slow dynamics (oscillatory and excursion events) using synchrophasor measurements. This paper focuses on detecting events with both fast and slow dynamics using wide-area frequency measurements. To this end, a novel method is proposed based on Weibull distribution, which we call as Weibull-based Excursion Transient and Oscillatory (WETO) method. The WETO method can identify the time of inception, location, and severity of the event in near real-time using only a single parameter, known as variability. The events are detected within a time window of 5 cycles using only frequency measurements. The proposed method is validated for the Indian as well as the North American grid disturbances, and the results show that it would be beneficial to the system operator in visualizing the true situation of the grid events.
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