Oligopolistic competition of gencos in reactive power ancillary service provisions

The need for a market based approach for reactive power procurement has been recognized by FERC. Due to the localized characteristic of reactive power, regulatory mechanisms are necessary to mitigate the possibility of holding market power by generators. The regulator is responsible for devising the regulatory mechanisms that provide incentives to generators to supply reactive power while preventing the abuse of market power. This paper proposes a mathematical model to simulate the strategic behavior of generators supplying reactive power while considering the system operator's schedule. The proposed method can be used by the regulator to simulate the market behavior in the reactive power supply. We further study how regulatory policies affect the strategic behavior. An alternative price cap method has been proposed and tested in the numerical example to mitigate the effect of strategic behavior of generators in reactive power procurement by the system operator. The numerical examples are tested on the Nordic 32-bus system. © 2009 IEEE.published_or_final_versio

Profit Analysis of Non-Identical Parallel System with Two Types of Failure Using Discrete Distribution

This paper has analyzed the two non-identical operative parallel systems considering two units (automatic and manual one) by using regenerative point technique. For theautomatic unit, the concept of inspection policy has been introduced to detect the kind of failures (major or minor) before being repaired by some repair mechanism. Butthe manual unit is free from such inspection policy. Various important measures of reliability i.e MTSF, steady-state availability, a busy period of repairman and inspector,profit function has been evaluated by designing a model for the system and using discrete distribution & regenerative point techniques. Profit function and MTSF are also analyzed graphically

Probability Analysis of a Complex System Working in a Sugar Mill with Repair Equipment Failure and Correlated Life Time

The aim of this paper is to present a reliability analysis of a complex (SJP) system in a sugar mill with the assumption that repair equipment may also fail during the repair. This paper considers the analysis of a three-unit system with one big unit and two small identical units of a SJP System in a sugar mill. Failure and Repair times of each unit are assumed to be correlated. Using regenerative point technique various reliability characteristics are obtained which are useful to system designers and industrial managers. Graphical behaviors of MTSF and profit function have also been studied

Complexity Studies in Some Piece wise Continuous Dynamical Systems

The, “Complex systems”, stands as a broad term for many diverse disciplines of science and engineering including natural & medical sciences. Complexities appearing in various dynamical systems during evolution are now interesting subjects of studies. Chaos appearing in various dynamical systems can also be viewed as a form of complexity. For some cases nonlinearities within the systems and for other cases piecewise continuity property of the system are responsible for such complexity. Dynamical systems represented by mathematical models having piecewise continuous properties show strange complexity character during evolution. Interesting recent articles explain widely on complexities in various systems. Observable quantities for complexity are measurement of Lyapunov exponents (LCEs), topological entropies, correlation dimension etc. The present article is related to study of complexity in systems having piecewise continuous properties. Some mathematical models are considered here in this regard including famous Lozi map, a discrete mathematical model and Chua circuit, a continuous model. Investigations have been carried forward to obtain various attractors of these maps appearing during evolution in diverse and interesting pattern for different set of values of parameters and for different initial conditions. Numerical investigations extended to obtain bifurcation diagrams, calculations of LCEs, topological entropies and correlation dimension together with their graphical representation

On Weighted Generalized Residual Information Measure

In this paper, we have proposed the concept of weighted generalized residual entropy of order α and type β, and have shown that the proposed measure characterizes the distribution function uniquely

Trigeminal Neuralgia: A Review

Trigeminal Neuralgia (TN) is a well-recognized syndrome characterized by lancinating attacks of severe facial pain. The diagnosis of TN is based on a history of characteristic pain attacks that are consistent with specific widely accepted criteria for the diagnosis. TN pain attacks may result from physiologic changes induced by a chronic partial injury to the brainstem trigeminal nerve root from a variety of causes. An early and accurate diagnosis of TN is important, because therapeutic interventions can reduce or eliminate pain attacks in the large majority of TN patients

Methodological Diversity in Citizen Science Mosquito Surveillance: A Scoping Review

Global concern regarding mosquito-borne disease emergence and re-emergence has driven the development of citizen science mosquito surveillance initiatives. Although these initiatives have shown great potential to assist local health authorities, ensuring outcomes are translatable to improved public health policy and practice remains challenging. Here we present a summary of citizen science mosquito surveillance programs worldwide, their focus, strategies, and outcomes, with a view to how best to apply this approach in their local areas. A scoping review of studies and reports was conducted through systematic search on electronic databases (Scopus, PubMed, Web of Science, and Google Scholar), grey literature, and other documents listed in the references of selected articles. A total of 33 citizen science studies included in this review described 29 citizen science mosquito surveillance projects operating in 16 countries, besides three programs with wide geographic coverage. The selected programs focused on different strategies and methods according to their local and national contextual needs. The majority of the programs reported being free or low in cost, and amenable to participants. Also, citizen scientists valued the opportunity to actively contribute to a scientific activity in which they saw value. Local and national programs have been successful in involving the broader public and yielding data on mosquito populations. However, to ensure the best public health outcomes, sustainability, and scalability, there is a need to continue engaging with stakeholders, including community members, researchers, public health agents, industry, and policymakers, and to bridge existing collaborations across different sectors

Evaluation of etoricoxib in patients undergoing total knee replacement surgery in a double-blind, randomized controlled trial.

BACKGROUND: Optimal postoperative pain management is important to ensure patient comfort and early mobilization. METHODS: In this double-blind, placebo- and active-controlled, randomized clinical trial, we evaluated postoperative pain following knee replacement in patients receiving placebo, etoricoxib (90 or 120 mg), or ibuprofen 1800 mg daily for 7 days. Patients \u3e=18 years of age who had pain at rest \u3e=5 (0--10 Numerical Rating Scale [NRS]) after unilateral total knee replacement were randomly assigned to placebo (N = 98), etoricoxib 90 mg (N = 224), etoricoxib 120 mg (N = 230), or ibuprofen 1800 mg (N = 224) postoperatively. Co-primary endpoints included Average Pain Intensity Difference at Rest over Days 1--3 (0- to 10-point NRS) and Average Total Daily Dose of Morphine over Days 1--3. Pain upon movement was evaluated using Average Pain Intensity Difference upon Knee Flexion (0- to 10-point NRS). The primary objective was to demonstrate analgesic superiority for the etoricoxib doses vs. placebo; the secondary objective was to demonstrate that the analgesic effect of the etoricoxib doses was non-inferior to ibuprofen. Adverse experiences (AEs) including opioid-related AEs were evaluated. RESULTS: The least squares (LS) mean (95% CI) differences from placebo for Pain Intensity Difference at Rest over Days 1--3 were -0.54 (-0.95, -0.14); -0.49 (-0.89, -0.08); and -0.45 (-0.85, -0.04) for etoricoxib 90 mg, etoricoxib 120 mg, and ibuprofen, respectively (p \u3c 0.05 for etoricoxib vs. placebo). Differences in LS Geometric Mean Ratio morphine use over Days 1--3 from placebo were 0.66 (0.54, 0.82); 0.69 (0.56, 0.85); and 0.66 (0.53, 0.81) for etoricoxib 90 mg, etoricoxib 120 mg, and ibuprofen, respectively (p \u3c 0.001 for etoricoxib vs. placebo). Differences in LS Mean Pain Intensity upon Knee Flexion were -0.37 (-0.85, 0.11); -0.46 (-0.94, 0.01); and -0.42 (-0.90, 0.06) for etoricoxib 90 mg, etoricoxib 120 mg, and ibuprofen, respectively. Opioid-related AEs occurred in 41.8%, 34.7%, 36.5%, and 36.3% of patients on placebo, etoricoxib 90 mg, etoricoxib 120 mg, and ibuprofen, respectively. CONCLUSIONS: Postoperative use of etoricoxib 90 and 120 mg in patients undergoing total knee replacement is both superior to placebo and non-inferior to ibuprofen in reducing pain at rest and also reduces opioid (morphine) consumption.Clinical trial registration: NCT00820027

The course of mental health problems in children presenting with abdominal pain in general practice

Objective. To investigate the course of mental health problems in children presenting to general practice with abdominal pain and to evaluate the extent to which abdominal pain characteristics during follow-up predict the presence of mental health problems at 12 months' follow-up. Design. A prospective cohort study with one-year follow-up. Setting. 53 general practices in the Netherlands, between May 2004 and March 2006. Subjects. 281 children aged 4-17 years. Main outcome measures. The presence of a depressive problem, an anxiety problem, and multiple non-specific somatic symptoms at follow-up and odds ratios of duration, frequency, and severity of abdominal pain with these mental health problems at follow-up. Results. A depressive problem persisted in 24/74 children (32.9%; 95% CI 22.3-44.9%), an anxiety problem in 13/43 (30.2%; 95% CI 17.2-46.1%) and the presence of multiple non-specific somatic symptoms in 75/170 children (44.1%; 95% CI 36.7-51.6%). None of the abdominal pain characteristics predicted a depressive or an anxiety problem at 12 months' follow-up. More moments of moderate to severe abdominal pain predicted the presence of multiple nonspecific somatic symptoms at follow-up. Conclusions. In one-third of the children presenting to general practice for abdominal pain, anxiety and depressive problems persist during one year of follow-up. Characteristics of the abdominal pain during the follow-up period do not predict anxiety or depressive problems after one-year follow-up. We recommend following over time children seen in primary care with abdominal pain

Recollection of childhood abdominal pain in adults with functional gastrointestinal disorders

It is hypothesized that adults who can recall abdominal pain as children are at risk of experiencing a functional gastrointestinal disorder (FGID), but this is not specific to any particular FGID. The aim of this study was to evaluate the association between recollecting abdominal pain as a child and experiencing a FGID