Design of distributed adaptive neural traffic signal timing controller by cuckoo search optimization

This paper focuses on designing an adaptive controller for controlling traffic signal timing. Urban traffic is an inevitable part in modern cities and traffic signal controllers are effective tools to control it. In this regard, this paper proposes a distributed neural network (NN) controller for traffic signal timing. This controller applies cuckoo search (CS) optimization methods to find the optimal parameters in design of an adaptive traffic signal timing control system. The evaluation of the performance of the designed controller is done in a multi-intersection traffic network. The developed controller shows a promising improvement in reducing travel delay time compared to traditional fixed-time control systems.

Design of robust distributed control for interconnected microgrids

Microgrids are currently controlled independently, according to local requirements and aims, often based on local control strategies and without coordination with other microgrids [1], [2]. However, it is anticipated that future sub-transmission and distribution systems will be composed of several interconnected microgrids and form a complex elec-tric network. Interconnecting together multiple microgrids can lead to undesirable dynamic behaviors, which have not been adequately examined so far. In particular, this paper dis-cusses power oscillations arising from multiple interconnected microgrids and proposes a control scheme based on a robust distributed control approach.

Design of reduced-order positive linear functional observers for positive time-delay systems

This brief considers a new problem of designing reduced-order positive linear functional observers for positive time-delay systems. The order of the designed functional observers is equal to the dimension of the functional state vector to be estimated. The designed functional observers always nonnegative at any time and they converge asymptotically to the true functional state vector. Moreover, conditions for the existence of such positive linear functional observers are formulated in terms of linear programming (LP). Numerical examples and simulation results are given to illustrate the effectiveness of the proposed design method.

Emergency nurse practitioner care and emergency department patient flow: case-control study

Objective: The present study aimed to compare ED waiting times (for medical assessment and treatment), treatment times and length of stay (LOS) for patients managed by an emergency nurse practitioner candidate (ENPC) with patients managed via traditional ED care. Methods: A case–control design was used. Patients were selected using the three most common ED discharge diagnoses for ENPC managed patients: hand/wrist wounds, hand/wrist fractures and removal of plaster of Paris. The ENPC group (n = 102) consisted of patients managed by the ENPC who had ED discharge diagnoses as mentioned above. The control group (n = 623) consisted of patients with the same ED discharge diagnoses who were managed via traditional ED care. Results: There were no significant differences in median waiting times, treatment times and ED LOS between ENPC managed patients and patients managed via traditional ED processes. There appeared to be some variability between diagnostic subgroups in terms of treatment times and ED LOS. Conclusion: Patient flow outcomes for ENPC managed patients are comparable with those of patients managed via usual ED processes.

Predictors of critical care admission in emergency department patients triaged as low to moderate urgency

Aim. This paper is a report of a study to identify predictors of critical care admission in emergency department patients triaged as low to moderate urgency that may be apparent early in the emergency department episode of care.

Background. Observations of clinical practice show that a number of emergency department patients triaged as low to moderate urgency require critical care admission, raising questions about the relationship between illness severity and physiological status early in the emergency department episode of care.

Methods. A retrospective case control design was used. All participants were aged over 18 years, triaged to Australasian Triage Scale categories 3, 4 or 5, and attended emergency department between 1 July 2004 and 30 June 2005. Cases were admitted to intensive care unit or coronary care unit and controls were admitted to general medical or surgical units. Cases (n = 193) and controls (n = 193) were matched by age, gender, emergency department discharge diagnosis and triage category.

Results. Critical care admission associated with: (i) a presenting complaint of nausea, vomiting and diarrhoea (OR = 3·40, 95%CI:1·22–9·47, P = 0·019), (ii) heart rate abnormalities at triage (OR = 2·10, 95%CI:1·19–3·71, P = 0·011), (iii) temperature abnormalities at triage (OR = 2·87 95%CI:1·05–7·89, P = 0·041), (iv) respiratory rate at first nursing assessment (OR = 1·66, 95%CI:1·05–2·06, P = 0·31) or (v) heart rate abnormalities at first nursing assessment (OR = 1·57, 95%CI = 1·04−2·39, P = 0·033).

Conclusion. Derangements in temperature, respiratory rate and heart appear to increase risk of critical care admission. Further work using a prospective approach is needed to establish which physiological parameters have the highest predictive validity, the level(s) of physiological abnormality with highest clinical utility, and the optimal timing for collection of physiological data.

Effect of emergency department fast track on emergency department length of stay : a case-control study

Objective: To examine the effect of fast track on emergency department (ED) length of stay (LOS).

Design and setting: Pair-matched case–control design in a public teaching hospital in metropolitan Melbourne, Australia.

Participants: Patients treated by the ED fast track (cases) between 1 January and 31 March 2007 were compared with patients treated by the usual ED processes (controls) from 1 July to 15 November 2006 (n = 822 matched pairs).

Intervention: ED fast track was established in November 2006 and focused on the management of patients with non-urgent complaints.

Main outcome measures: The primary outcome measure was ED LOS for fast-track patients. Secondary outcomes were waiting times and ED LOS for other ED patients.

Results: Median ED LOS for non-admitted patients was 132 minutes (interquartile range (IQR) 83–205.25) for controls and 116 minutes (IQR 75.5–159.0) for cases (p<0.01). Fast-track patients had a significantly higher incidence of discharge within 2 h (53% vs 44%, p<0.01) and 4 h (92% vs 84%, p<0.01).

Conclusions: ED fast track decreased ED LOS for non-admitted patients without compromising waiting times and ED LOS for other ED patients

Power control in CDMA systems based on channel identification

Power control design is a critical aspect of CDMA cellular systems design. This paper develops an adaptive power controller design method for CDMA systems. The key to the power control design is on the recursive identification of the underlying wireless stochastic channel model parameters. The identification process guarantees the power controller to work well for systems in unknown or time varying network environment.

Uplink power control via adaptive hmm estimation

Transmit power control is an important consideration in the cellular system design since it increases system capacity, improves QoS and reduces multi-user interference. In this paper, an adaptive power control design based on the identification of the underlying pathloss of the fading channel is presented. Making power control decisions based on the measured received power allows to model the fading channel pathloss dynamics with a Hidden Markov Model. Applying the online HMM identification algorithm enables accurate estimation of the real pathloss which ensures efficient performance of the suggested power control scheme.

Leader-follower consensus control of a class of nonholonomic systems

In this paper, we propose a systematic solution to the leader-follower consensus of a class of nonholonomic chained form systems. The control design, which is reminiscent of terminal sliding mode and multi-surface sliding mode control methods, is presented to guarantee the convergence of multiple sliding surfaces, which also implies the convergence of the proposed consensus error function. On these sliding surfaces, the desired leader-follower consensus can be reached for multi-agent network formed by the nonholonomic chained form systems.

Uplink power control via adaptive Hidden-Markov-Model-Based pathloss estimation

Dynamic variations in channel behavior is considered in transmission power control design for cellular radio systems. It is well known that power control increases system capacity, improves Quality of Service (QoS), and reduces multiuser interference. In this paper, an adaptive power control design based on the identification of the underlying pathloss dynamics of the fading channel is presented. Formulating power control decisions based on the measured received power levels allows modeling the fading channel pathloss dynamics in terms of a Hidden Markov Model (HMM). Applying the online HMM identification algorithm enables accurate estimation of the real pathloss ensuring efficient performance of the suggested power control scheme.

Adaptive fuzzy multi-surface sliding control of multiple-input and multiple-output autonomous flight systems

In this study, we proposed an adaptive fuzzy multi-surface sliding control (AFMSSC) for trajectory tracking of 6 degrees of freedom inertia coupled aerial vehicles with multiple inputs and multiple outputs (MIMO). It is shown that an adaptive fuzzy logic-based function approximator can be used to estimate the system uncertainties and an iterative multi-surface sliding control design can be carried out to control flight. Using AFMSSC on MIMO autonomous flight systems creates confluent control that can account for both matched and mismatched uncertainties, system disturbances and excitation in internal dynamics. It is proved that the AFMSSC system guarantees asymptotic output tracking and ultimate uniform boundedness of the tracking error. Simulation results are presented to validate the analysis.

Robust control for power sharing in microgrids with low-inertia wind and PV generators

This paper presents a robust control design scheme for a multidistributed energy resource (DER) microgrid for power sharing in both interconnected and islanded modes. The scheme is proposed for micgrogrids consisting of photovoltaic (PV) units and wind turbine driven doubly fed induction generators (DFIGs). A battery is integrated with each of the wind and solar DER units. The control scheme has two levels: 1) one centralized multi-input–multi-output robust controller for regulating the set reference active and reactive powers and 2) local real and reactive power droop con-trollers, one on each DER unit. The robust control scheme utilizes multivariable H1 control to design controllers that are robust to the changes in the network and system nonlinearities. The effectiveness of the proposed controller is demonstrated through large-distur-bance simulations, with complete nonlinear models, on a test micro-grid. It is found that the power sharing controllers provide excellent performance against large disturbances and load variations during islanding transients and interconnected operation.

Characteristics evaluation of an LMI-synthesis H∞ controller for a superconducting magnetic energy systems applied in power systems

© 2015 IEEE.This paper presents an H« controller synthesised based on linear matrix inequalities (LMI) for a current source converter based superconducting magnetic energy systems (SMESs) connected to a node of power systems where the regulation of grid current has considered as a control objective. To facilitate the control design, the system is represented in terms of state space realization with uncertainties. The control design involves selecting proper weighting functions and performing LMI-synthesis. The controller order is reduced by Henkel-norm method. Simulations are carried out to evaluate the characteristics of the controller under parametric uncertainties. It is found out that the proposed controller is inherently stable, possesses significantly small tracking error, and preserves robust performance for the SMES.

Selected Ranked Set Sampling

This paper proposes a sampling procedure called selected ranked set sampling (SRSS), in which only selected observations from a ranked set sample (RSS) are measured. This paper describes the optimal linear estimation of location and scale parameters based on SRSS, and for some distributions it presents the required tables for optimal selections. For these distributions, the optimal SRSS estimators are compared with the other popular simple random sample (SRS) and RSS estimators. In every situation the estimators based on SRSS are found advantageous at least in some respect, compared to those obtained from SRS or RSS. The SRSS method with errors in ranking is also described. The relative precision of the estimator of the population mean is investigated for different degrees of correlations between the actual and erroneous ranking. The paper reports the minimum value of the correlation coefficient between the actual and the erroneous ranking required for achieving better precision with respect to the usual SRS estimator and with respect to the RSS estimator.

Early impact of the BEST intervention for parents stressed by adolescent substance abuse.

Youth involvement in substance abuse can be a source of considerable distress for their parents. Unilateral family interventions have been advocated as one means by which concerned family members can be supported to assist substance-abusing family members. To date there has been little research examining the impact of unilateral family interventions on the directly participating family members. In this study the early impact of an 8-week parent-group programme known as Behavioural Exchange Systems Training (BEST) was evaluated using a quasi-experimental, waiting list control design. The professionally led programme had been developed to support and assist parents in their efforts to cope with adolescent substance abuse. Subjects were 66 parents (48 families) accepted for entry into the programme between 1997 and 1998. Comparison was made between 46 parents offered immediate entry into the programme and 20 parents whose entry to the programme was delayed by an 8-week waiting list. At the first assessment 87% of parents showed elevated mental health symptoms on the General Health Questionnaire. Evidence suggested exposure to the intervention had a positive impact on parents. Compared to parents on the waiting list, parents entered immediately into the intervention demonstrated greater reductions in mental health symptoms, increased parental satisfaction, and increased use of assertive parenting behaviours.