38 research outputs found
May the Guide Be With You: CA-facilitated Information Elicitation to Prevent Service Failure
Companies automate the delivery of their online services by deploying artificial intelligence-based conversational agents (CAs). However, contemporary CAs still struggle to reliably answer the full range of requests from support seekers. To avoid service failure, service delivery activities of CAs and service employees should be interconnected by a handover of requests. This form of hybrid service delivery requires support seekers to disclose relevant information so that CAs can relay them to service employees prior to an imminent failure. By integrating and extending design knowledge from two DSR projects, we derive four design principles (DPs) to prepare handovers. These DPs guided the implementation of a service script in a CA prototype to facilitate the elicitation of information from support seekers. Based on two evaluation episodes, we show that support seekers feel supported by the CA in disclosing information which results in elaborate input for subsequent processing by service employees after handover
Photocurrent dynamics in a poly(phenylene vinylene)-based photorefractive composite,â Phys
All parameters describing the charge carrier dynamics in a polyÍphenylene vinyleneÍ-based photorefractive ÍPRÍ composite relevant to PR grating dynamics were determined using photoconductivity studies under various illumination conditions. In particular, the values of the coefficients for trap filling and recombination of charges with ionized sensitizer molecules could be extracted independently. It is concluded that the PR growth time without preillumination is mostly determined by the competition between deep trap filling and recombination with ionized sensitizer molecules. Further, the pronounced increase in PR speed upon homogeneous preillumination ÍgatingÍ as reported recently is quantitatively explained by deep trap filling
Evidence of Isotopic Fractionation During Vapor Exchange Between the Atmosphere and the Snow Surface in Greenland
Several recent studies from both Greenland and Antarctica have reported significant changes in the water isotopic composition of nearâsurface snow between precipitation events. These changes have been linked to isotopic exchange with atmospheric water vapor and sublimationâinduced fractionation, but the processes are poorly constrained by observations. Understanding and quantifying these processes are crucial to both the interpretation of ice core climate proxies and the formulation of isotopeâenabled general circulation models. Here, we present continuous measurements of the water isotopic composition in surface snow and atmospheric vapor together with nearâsurface atmospheric turbulence and snowâair latent and sensible heat fluxes, obtained at the East Greenland IceâCore Project drilling site in summer 2016. For two 4âdayâlong time periods, significant diurnal variations in atmospheric water isotopologues are observed. A model is developed to explore the impact of this variability on the surface snow isotopic composition. Our model suggests that the snow isotopic composition in the upper subcentimeter of the snow exhibits a diurnal variation with amplitudes in ÎŽ18O and ÎŽD of ~2.5â° and ~13â°, respectively. As comparison, such changes correspond to 10â20% of the magnitude of seasonal changes in interior Greenland snow pack isotopes and of the change across a glacialâinterglacial transition. Importantly, our observation and model results suggest, that sublimationâinduced fractionation needs to be included in simulations of exchanges between the vapor and the snow surface on diurnal timescales during summer cloudâfree conditions in northeast Greenland
Near-infrared sensitivity enhancement of photorefractive polymer composites by pre-illumination
Among the various applications for reversible holographic storage media, a particularly interesting one is time-gated holographic imaging (TGHI). This technique could provide a noninvasive medical diagnosis tool, related to optical coherence tomography. In this technique, biological samples are illuminated within their transparency windowwith near-infrared light, and information about subsurface features is obtained by a detection method that distinguishes between reflected photons originating from a certain depth and those scattered from various depths. Such an application requires reversible holographic storage media with very high sensitivity in the near-infrared. Photorefractive materials, in particular certain amorphous organic systems, are in principle promising candidate media, but their sensitivity has so far been too low, mainly owing to their long response times in the near-infrared. Here we introduce an organic photorefractive materialâa composite based on the poly(arylene vinylene) copolymer TPD-PPVâthat exhibits favourable near-infrared characteristics. We show that pre-illumination of this material at a shorter wavelength before holographic recording improves the response time by a factor of 40. This process was found to be reversible. We demonstrate multiple holographic recording with this technique at video rate under practical conditions