Location Awareness in Multi-Agent Control of Distributed Energy Resources

The integration of Distributed Energy Resource (DER) technologies such as heat pumps, electric vehicles and small-scale generation into the electricity grid at the household level is limited by technical constraints. This work argues that location is an important aspect for the control and integration of DER and that network topology can inferred without the use of a centralised network model. It addresses DER integration challenges by presenting a novel approach that uses a decentralised multi-agent system where equipment controllers learn and use their location within the low-voltage section of the power system. Models of electrical networks exhibiting technical constraints were developed. Through theoretical analysis and real network data collection, various sources of location data were identified and new geographical and electrical techniques were developed for deriving network topology using Global Positioning System (GPS) and 24-hour voltage logs. The multi-agent system paradigm and societal structures were examined as an approach to a multi-stakeholder domain and congregations were used as an aid to decentralisation in a non-hierarchical, non-market-based approach. Through formal description of the agent attitude INTEND2, the novel technique of Intention Transfer was applied to an agent congregation to provide an opt-in, collaborative system. Test facilities for multi-agent systems were developed and culminated in a new embedded controller test platform that integrated a real-time dynamic electrical network simulator to provide a full-feedback system integrated with control hardware. Finally, a multi-agent control system was developed and implemented that used location data in providing demand-side response to a voltage excursion, with the goals of improving power quality, reducing generator disconnections, and deferring network reinforcement. The resulting communicating and self-organising energy agent community, as demonstrated on a unique hardware-in-the-loop platform, provides an application model and test facility to inspire agent-based, location-aware smart grid applications across the power systems domain

The Role of Gender and How it Relates to Conflict Management Style and School Culture

This investigation focused on principals, by gender, and the impact that the principals\u27 conflict management style had on cultural aspects in schools. Findings were: principals with a conflict management style that is high in dominating show lower school culture scores in professional development, and, conversely, principals with a conflict management style that is high in initiating indicate higher school culture scores in teacher collaboration. When split by gender, the findings were: male principals whose conflict management style is dominating receive lower school culture scores in teacher collaboration, while female principals whose conflict management style was viewed as integrating receive higher school culture scores in professional development and teacher collaboration

The Role of Gender and How it Relates to Conflict Management Style and School Culture

This investigation focused on principals, by gender, and the impact that the principals\u27 conflict management style had on cultural aspects in schools. Findings were: principals with a conflict management style that is high in dominating show lower school culture scores in professional development, and, conversely, principals with a conflict management style that is high in initiating indicate higher school culture scores in teacher collaboration. When split by gender, the findings were: male principals whose conflict management style is dominating receive lower school culture scores in teacher collaboration, while female principals whose conflict management style was viewed as integrating receive higher school culture scores in professional development and teacher collaboration

Psychophysical correlates of global motion processing in the aging visual system: a critical review

The consequences of visual decline in aging have a fundamental and wide-reaching impact on age-related quality of life. It is of concern therefore that evidence suggests that normal aging is accompanied by impairments in the ability to effectively encode global motion. Global motion perception is a fundamentally important process. It enables us to determine the overall velocity of spatially extensive objects in the world and provides us with information about our own body movements. Here, we review what is currently known about the effects of age on performance for encoding the global motion information available in random dot kinematograms (RDKs), a class of stimuli widely used to probe the mechanisms underlying motion perception. We conclude that age-related deficits in global motion perception are not all encompassing. Rather, they appear to be specific to certain stimulus conditions. We also examine evidence for an interaction between age and gender and consider the efficacy of techniques such as visual perceptual learning that may attenuate some of the visual deficits in the older adult population

The role of contrast sensitivity in global motion processing deficits in the elderly

This study compared the effects of age on the perception of translational, radial, and rotational global motion patterns. Motion coherence thresholds were measured for judging the direction of each motion type as a function of contrast (visibility) and temporal sampling rate in young and elderly participants. Coherence thresholds decreased as dot contrast increased asymptoting at high dot contrasts but were higher in elderly compared to young participants. This equated to global motion impairment in the elderly of a factor of around 2, characterized by a shift of the threshold vs. contrast function along the horizontal axes (dot contrast). The effect of contrast interacted with the temporal sampling rate. Old participants were deleteriously affected by reduced temporal sampling particularly at low contrasts. The findings suggest that age- related changes in global motion perception may be driven principally by deficits in contrast encoding, rather than by deficits in motion integration and suggest a role for increased internal noise in the older visual system

Binocular summation of second-order global motion signals in human vision

Although many studies have examined the principles governing first-order global motion perception, the mechanisms that mediate second-order global motion perception remain unresolved. This study investigated the existence, nature and extent of the binocular advantage for encoding second-order (contrast-defined) global motion. Motion coherence thresholds (79.4 % correct) were assessed for determining the direction of radial, rotational and translational second-order motion trajectories as a function of local element modulation depth (contrast) under monocular and binocular viewing conditions. We found a binocular advantage for second-order global motion processing for all motion types. This advantage was mainly one of enhanced modulation sensitivity, rather than of motion-integration. However, compared to findings for first-order motion where the binocular advantage was in the region of a factor of around 1.7 [Hess et al., 2007, Vision Research 47, 1682-1692 & the present study], the binocular advantage for second-order global 2 motion was marginal, being in the region of around 1.2. This weak enhancement in sensitivity with binocular viewing is considerably less than would be predicted by conventional models of either probability summation or neural summation

Towards targeted screening for acute HIV infections in British Columbia

<p>Abstract</p> <p>Background</p> <p>Our objective was to describe the characteristics of acute and established HIV infections diagnosed in the Canadian province of British Columbia. Province-wide HIV testing and surveillance data were analyzed to inform recommendations for targeted use of screening algorithms to detect acute HIV infections.</p> <p>Methods</p> <p>Acute HIV infection was defined as a confirmed reactive HIV p24 antigen test (or HIV nucleic acid test), a non-reactive or reactive HIV EIA screening test and a non-reactive or indeterminate Western Blot. Characteristics of unique individuals were identified from the British Columbia HIV/AIDS Surveillance System. Primary drug resistance and HIV subtypes were identified by analyzing HIV <it>pol </it>sequences from residual sera from newly infected individuals.</p> <p>Results</p> <p>From February 2006 to October 2008, 61 individuals met the acute HIV infection case definition, representing 6.2% of the 987 newly diagnosed HIV infections during the analysis period. Acute HIV infection cases were more likely to be men who have sex with men (crude OR 1.71; 95% CI 1.01-2.89], to have had a documented previous negative HIV test result (crude OR 2.89; 95% CI 1.52-5.51), and to have reported a reason for testing due to suspected seroconversion symptoms (crude OR 5.16; 95% CI 2.88-9.23). HIV subtypes and rates of transmitted drug resistance across all classes of drugs were similar in persons with both acute and established HIV infections.</p> <p>Conclusions</p> <p>Targeted screening to detect acute HIV infection is a logical public health response to the HIV epidemic. Our findings suggest that acute HIV infection screening strategies, in our setting, are helpful for early diagnosis in men who have sex with men, in persons with seroconversion symptoms and in previously negative repeat testers.</p

Analyses of cerebral microdialysis in patients with traumatic brain injury: relations to intracranial pressure, cerebral perfusion pressure and catheter placement

<p>Abstract</p> <p>Background</p> <p>Cerebral microdialysis (MD) is used to monitor local brain chemistry of patients with traumatic brain injury (TBI). Despite an extensive literature on cerebral MD in the clinical setting, it remains unclear how individual levels of real-time MD data are to be interpreted. Intracranial pressure (ICP) and cerebral perfusion pressure (CPP) are important continuous brain monitors in neurointensive care. They are used as surrogate monitors of cerebral blood flow and have an established relation to outcome. The purpose of this study was to investigate the relations between MD parameters and ICP and/or CPP in patients with TBI.</p> <p>Methods</p> <p>Cerebral MD, ICP and CPP were monitored in 90 patients with TBI. Data were extensively analyzed, using over 7,350 samples of complete (hourly) MD data sets (glucose, lactate, pyruvate and glycerol) to seek representations of ICP, CPP and MD that were best correlated. MD catheter positions were located on computed tomography scans as pericontusional or nonpericontusional. MD markers were analyzed for correlations to ICP and CPP using time series regression analysis, mixed effects models and nonlinear (artificial neural networks) computer-based pattern recognition methods.</p> <p>Results</p> <p>Despite much data indicating highly perturbed metabolism, MD shows weak correlations to ICP and CPP. In contrast, the autocorrelation of MD is high for all markers, even at up to 30 future hours. Consequently, subject identity alone explains 52% to 75% of MD marker variance. This indicates that the dominant metabolic processes monitored with MD are long-term, spanning days or longer. In comparison, short-term (differenced or Δ) changes of MD vs. CPP are significantly correlated in pericontusional locations, but with less than 1% explained variance. Moreover, CPP and ICP were significantly related to outcome based on Glasgow Outcome Scale scores, while no significant relations were found between outcome and MD.</p> <p>Conclusions</p> <p>The multitude of highly perturbed local chemistry seen with MD in patients with TBI predominately represents long-term metabolic patterns and is weakly correlated to ICP and CPP. This suggests that disturbances other than pressure and/or flow have a dominant influence on MD levels in patients with TBI.</p