Een navigatie-agent in virtual reality

We geven een korte beschrijving van ons werk gericht op het ontwerpen van een navigatie-agent voor een virtuele werled die met natuurlijke taal aangesproken kan worden. Het project is gestart als afstudeerwerk van de tweede auteur. Dit artikel beschrijft voornamelijk zijn werk. Het werk wordt op dit moment voortgezet binnen een nationaal project op het gebied van toegankelijkheid van webpagina’s en binnen een aantal kleinere, deels ook door afstudeerders uitgevoerde, deelprojecten. De navigatieagent is onderdeel van een agent-raamwerk waarbinnen gecommuniceerd kan worden met andere agents. De navigatietaak bestaat uit het gidsen van bezoekers in de omgeving en het beantwoorden van vragen over deze omgeving (een theatergebouw). Bezoekers worden uitgenodigd het gebouw te exploreren, rond te kijken, vragen te stellen en kunnen al doende advies krijgen van de navigatie-agent. Een plattegrond is aan de omgeving toegevoegd, zodat bezoekers kunnen refereren aan lokaties en objecten op deze kaart, zowel in natuurlijke taal als door aanwijzen en klikken met een muis. Daardoor is sprake van een multi-modaal systeem met cross-modale referentiemogelijkheden

Adherence to low-dose methotrexate in children with juvenile idiopathic arthritis using a sensitive methotrexate assay

BACKGROUND: Low-dose weekly methotrexate (MTX) is the mainstay of treatment in juvenile idiopathic arthritis. Unfortunately, a substantial part of patients has insufficient efficacy of MTX. A potential cause of this inadequate response is suboptimal drug adherence. The aim of this study was to assess MTX adherence in juvenile idiopathic arthritis patients by quantification of MTX concentrations in plasma. Secondly, the association between MTX concentrations and either self-reported adherence issues, or concomitant use of biologics was examined. METHODS: This was a retrospective, observational study using plasma samples from juvenile idiopathic arthritis patients. An ultrasensitive liquid chromatography-tandem mass spectrometry method was developed for quantification of MTX and its metabolite 7-hydroxy-MTX in plasma. The determined MTX plasma concentrations in juvenile idiopathic arthritis patients were compared with corresponding adherence limits, categorising them as either adherent or possibly non-adherent to MTX therapy. RESULTS: Plasma samples of 43 patients with juvenile idiopathic arthritis were analysed. Adherence to MTX in this population was 88% shortly after initiation of MTX therapy and decreased to 77% after one year of treatment. Teenagers were more at risk for non-adherence (p = 0.002). We could not find an association between MTX adherence with either self-reported adherence issues, nor with the use of concomitant biological treatment (p = 1.00 and p = 0.27, respectively; Fisher's Exact). CONCLUSIONS: Quantification of MTX in plasma is a feasible and objective method to assess adherence in patients using low-dose weekly MTX. In clinical practice, the use of this method could be a helpful tool for physicians to refute or support suspicion of non-adherence to MTX therapy

Dynamics of Low-Level Viremia and Immune Activation after Switching to a Darunavir-Based Regimen

There is an ongoing debate regarding whether low-level viremia (LLV), in particular persistent LLV, during HIV treatment with optimal adherence originates from low-level viral replication, viral production, or both. We performed an observational study in 30 individuals with LLV who switched to a boosted darunavir (DRV)-based therapy. In-depth virological analyses were used to characterize the viral population and the (activity) of the viral reservoir. Immune activation was examined using cell-bound and soluble markers. The primary outcome was defined as the effect on HIV-RNA and was categorized by responders (50 cp/mL). At week 24, 53% of the individuals were considered responders, 40% non-responders, and 7% could not be assigned. Sequencing showed no evolution or selection of drug resistance in the non-responders. Production of defective virus with mutations in either the protease (D25N) or RT active site contributed to persistent LLV in two individuals. We show that in about half of the study participants, the switch to a DRV-based regimen resulted in a viral response indicative of ongoing low-level viral replication as the cause of LLV before the switch. Our data confirm that in clinical management, high genetic barrier drugs like DRV are a safe choice, irrespective of the source of LLV

Virological and immunological correlates of HIV posttreatment control after temporal antiretroviral therapy during acute HIV infection

Objective:People with HIV rarely control viral replication after cessation of antiretroviral therapy (ART). We present a person with HIV with extraordinary posttreatment control (PTC) for over 23 years after temporary ART during acute HIV infection (AHI) leading to a new insight in factors contributing to PTC.Design/methods:Viral reservoir was determined by HIV qPCR, Intact Proviral DNA Assay, and quantitative viral outgrowth assay. Viral replication kinetics were determined in autologous and donor PBMC. IgG levels directed against HIV envelope and neutralizing antibodies were measured. Immune phenotyping of T cells and HIV-specific T-cell responses were analyzed by flow cytometry.Results:The case presented with AHI and a plasma viral load of 2.7 million copies/ml. ART was initiated 2 weeks after diagnosis and interrupted after 26 months. Replicating virus was isolated shortly after start ART. At 18 years after treatment interruption, HIV-DNA in CD4+T cells and low levels of HIV-RNA in plasma (<5 copies/ml) were detectable. Stable HIV envelope glycoprotein-directed IgG was present during follow-up, but lacked neutralizing activity. Strong antiviral CD8+T-cell responses, in particular targeting HIV-gag, were detected during 25 years follow-up. Moreover, we found a P255A mutation in an HLA-B∗44 : 02 restricted gag-epitope, which was associated with decreased replication.Conclusion:We describe an exceptional case of PTC, which is likely associated with sustained potent gag-specific CD8+T-cell responses in combination with a replication attenuating escape mutation in gag. Understanding the initiation and preservation of the HIV-specific T-cell responses could guide the development of strategies to induce HIV control

Internet of Things in Sustainable Energy Systems

Our planet has abundant renewable and conventional energy resources but technological capability and capacity gaps coupled with water-energy needs limit the benefits of these resources to citizens. Through IoT technology solutions and state-of-the-art IoT sensing and communications approaches, the sustainable energy-related research and innovation can bring a revolution in this area. Moreover, by the leveraging current infrastructure, including renewable energy technologies, microgrids, and power-to-gas (P2G) hydrogen systems, the Internet of Things in sustainable energy systems can address challenges in energy security to the community, with a minimal trade-off to environment and culture. In this chapter, the IoT in sustainable energy systems approaches, methodologies, scenarios, and tools is presented with a detailed discussion of different sensing and communications techniques. This IoT approach in energy systems is envisioned to enhance the bidirectional interchange of network services in grid by using Internet of Things in grid that will result in enhanced system resilience, reliable data flow, and connectivity optimization. Moreover, the sustainable energy IoT research challenges and innovation opportunities are also discussed to address the complex energy needs of our community and promote a strong energy sector economy

Process mining in a multi-agent auctioning system

Summary. Both process mining and multi agent simulations are relatively new re- search areas, both evolving rapidly. In multi agent simulations, techniques are being developed to make agents more intelligent and more adaptive to their environment. In process mining, the focus has shifted from discovering a complete process model from an execution log, to the development of all kind of analysis techniques related to processes. In this paper, we combine the two research areas by showing that process mining techniques, applied to the communication logs of multi-agent simu- lations, can help in understanding the behaviour of agents. Furthermore, we show that process mining could actually help agents to adapt to their environment, by enabling them to discover why another agent makes certain decisions instead of just reacting on the fact that the other agent made a decision

Process mining in a multi-agent auctioning system

Summary. Both process mining and multi agent simulations are relatively new re- search areas, both evolving rapidly. In multi agent simulations, techniques are being developed to make agents more intelligent and more adaptive to their environment. In process mining, the focus has shifted from discovering a complete process model from an execution log, to the development of all kind of analysis techniques related to processes. In this paper, we combine the two research areas by showing that process mining techniques, applied to the communication logs of multi-agent simu- lations, can help in understanding the behaviour of agents. Furthermore, we show that process mining could actually help agents to adapt to their environment, by enabling them to discover why another agent makes certain decisions instead of just reacting on the fact that the other agent made a decision