arXiv subjects

Himanshu Verma

Publications and source records attributed to Himanshu Verma.

At least 19 recordsLinked to original sources

arXiv2026

Disentangling Innovation Practices in Automation-Adopting Organizations: a Co-Performance Perspective

As organizations increasingly adopt automation, innovation practitioners are responsible for selecting, adapting, testing, and implementing externally sourced innovations. However, little is known about how these upstream practices shape worker-automation arrangements, limiting our ability to intervene in innovation practice to address automation adoption challenges. To disentangle this relationship, we interviewed nine innovation practitioners at a major European airport pursuing long-term autonomous operations and analyzed their practices through a co-performance lens. We synthesize five co-performance design principles and examine where current practices align or conflict. Our findings reveal tensions: innovation practitioners prioritize full-automation arrangements while postponing human considerations; contextual constraints shape solutions, but openness to reconfiguration remains limited; and co-learning rarely extends beyond pilot phases. These insights provide HCI research and practice with guidance for reframing the conceptualization of automation, particularly by encouraging earlier consideration of human roles, promoting iterative visions, and recognizing workers as co-designers throughout innovation pipelines.

cs.HC↗

arXiv2026

An Updated SynthPop Model for Microlensing Simulations I: Model Description & Evaluation

The optimization and interpretation of microlensing surveys depends on having an accurate model of the Milky Way. However, existing population synthesis Galactic modeling tools often perform poorly in replicating the stellar contents of the inner Galactic bulge region and reproducing microlensing survey results. We present an updated Galactic model implementation within the \synthpop framework that has been tuned for simulating the upcoming {\it Nancy Grace Roman Space Telescope}'s Galactic Bulge Time Domain Survey (RGBTDS). We evaluate the model against stellar catalogs and kinematics from optical and infrared surveys toward the Galactic bulge, finding good agreement in much of the bulge, including the RGBTDS' contiguous lower bulge fields. However, within Galactic latitudes of $b\lesssim0.5^\circ$ of the Galactic plane, some inconsistencies arise which may impact projections for the RGBTDS' Galactic center field. The model over-predicts optical microlensing event rate per star measurements by a $\sim20$\%, but detailed comparisons to near-infrared measurements are hampered by their lack of detection efficiencies. {\it Roman}'s GBTDS and Galactic Plane Survey will be instrumental in resolving the remaining model inconsistencies and improving our understanding of the structure of the central few degrees of our Galaxy.

astro-ph.GA↗

arXiv2026

Microlensing of fast and slow compact objects

Gravitational microlensing constraints on non-standard compact objects are conventionally derived assuming lenses trace the dark matter halo with velocities following a Maxwell-Boltzmann distribution centered around $10^{-3}c$. However, a variety of theoretical scenarios predict populations of compact objects whose velocities deviate dramatically from those of virialized halo dark matter -- ultrarelativistic primordial black holes from cosmic string collapse, mirror neutron stars, gravitationally kicked black hole merger remnants, dark matter nuggets, free floaters ejected from gravitationally bound systems, disk-formed compact objects, and so on. For a given Einstein crossing time, the speed-mass degeneracy inherent in it means that fast (slow) lenses produce events at larger (smaller) masses than spanned by standard windows, opening qualitatively new regions of parameter space. After deriving model-independent upper limits on the microlensing event rate, we obtain mass-dependent constraints on the density of lens populations with speeds spanning $10^{-4}c-10^{-1}c$ from surveys of M31 by Subaru-HSC and the LMC by OGLE with different observing cadences. We do this for two benchmark velocity distributions -- Maxwell-Boltzmann and Dirac delta -- and two spatial distributions -- uniform and NFW, and exclude lens densities and masses that differ from dark matter constraints by orders of magnitude. We examine the effect of the transverse motion of the source and observer relative to the lensing tube, which becomes significant for our slow lenses. We also show that, unlike in dark matter searches, for our fast lenses an increase in the cadence of observations would probe smaller masses without suppression of event rates from the finite source and wave optics effects.

astro-ph.CO↗

arXiv2026

Technique-agnostic exoplanet demography for the Roman era -- I. Testing a demography retrieval framework using simulated Kepler-like transit datasets

The Nancy Grace Roman Space Telescope (Roman) will unveil for the first time the full architecture of planetary systems across Galactic distances through the discovery of up to 200,000 cool and hot exoplanets using microlensing and transit detection methods. Roman's huge exoplanet haul, and Galactic reach, will require new methods to leverage the full exoplanet demographic content of the combined microlensing and transit samples, given the different sensitivity bias of the techniques to planet and host properties and Galactic location. We present a framework for technique-agnostic exoplanet demography (TAED) that can allow large, multi-technique exoplanet samples distributed over Galactic distance scales to be combined for demographic studies. Our TAED forward modelling and retrieval framework uses parameterised model exoplanet demographic distributions to embed planetary systems within a stellar population synthesis model of the Galaxy, enabling internally consistent forecasts to be made for all detection methods that are based on spatio-kinematic system properties. In this paper, as a first test of the TAED framework, we apply it to simulated transit datasets based on the Kepler Data Release 25 to assess parameter recovery accuracy and method scalability for a single large homogeneous dataset. We find that optimisation using differential evolution provides a computationally scalable framework that gives a good balance between computational efficiency and accuracy of parameter recovery.

astro-ph.EP↗

arXiv2026

The Bots of Persuasion: Examining How Conversational Agents' Linguistic Expressions of Personality Affect User Perceptions and Decisions

Large Language Model-powered conversational agents (CAs) are increasingly capable of projecting sophisticated personalities through language, but how these projections affect users is unclear. We thus examine how CA personalities expressed linguistically affect user decisions and perceptions in the context of charitable giving. In a crowdsourced study, 360 participants interacted with one of eight CAs, each projecting a personality composed of three linguistic aspects: attitude (optimistic/pessimistic), authority (authoritative/submissive), and reasoning (emotional/rational). While the CA's composite personality did not affect participants' decisions, it did affect their perceptions and emotional responses. Particularly, participants interacting with pessimistic CAs felt lower emotional state and lower affinity towards the cause, perceived the CA as less trustworthy and less competent, and yet tended to donate more toward the charity. Perceptions of trust, competence, and situational empathy significantly predicted donation decisions. Our findings emphasize the risks CAs pose as instruments of manipulation, subtly influencing user perceptions and decisions.

cs.HC↗

arXiv2025

Microlensing Black Hole Shadows-II: Constraining Primordial Black Hole Dark Matter using the photon rings of M87 and Sgr A*

The resolution of photon rings of Sgr~A$^*$ and M87 is the next milestone of upcoming EHT-like interferometries. We extend the formalism developed in our previous work~\cite{Verma:2023hes} to constrain primordial black hole (PBH) dark matter using microlensing-induced distortions of black hole shadows. Building upon the theoretical framework for microlensing of photon rings, we apply this methodology to both Sgr A* and M87, considering multiple PBH populations: (i) PBH dark matter spikes around central supermassive black holes, (ii) NFW halo contributions in the Milky Way and M87 galaxies, and (iii) foreground Milky Way PBH dark matter affecting M87* observations. The microlensing signal manifests as a time-dependent asymmetry and deformation of the photon ring, providing the most sensitive observable for lensing effects. We assess the detectability of these signatures with future EHT-like interferometers. Our analysis reveals that M87* provides the strongest constraints on PBH dark matter. We show that the absence of photon-ring asymmetries in observations with angular resolution of order $0.1\,μ{\rm as}$ can constrain PBHs in the mass range $10^{-5}\,M_\odot \lesssim M_{\rm PBH} \lesssim 10^{6}\,M_\odot$, with maximal sensitivity near $M_{\rm PBH}\sim10^{3}\,M_\odot$, for PBH dark matter fractions as small as $f_{\rm PBH}\sim10^{-2}$.

astro-ph.GA↗

arXiv2025

Predictions of the Nancy Grace Roman Space Telescope Galactic Exoplanet Survey. V. Detection Rates of Multiplanetary Systems in High Magnification Microlensing Events

The Nancy Grace Roman Space Telescope will expand the reach of gravitational microlensing surveys by increasing the number of events monitored and the precision of their light curves. We investigate Roman's ability to detect triple-lens microlensing systems, cases where a foreground star with two bound exoplanets produces detectable anomalies in a microlensing event, using its planned high-cadence observations toward the Galactic bulge. We simulate a large set of high-magnification microlensing light curves based on Roman's expected survey characteristics. A detection criterion, based on a required $χ^2$ improvement for a two-planet model, is applied to determine whether the second planet can be reliably distinguished from a single-planet (binary-lens) model. Our simulations show that the majority of two-planet microlensing events would be detectable with Roman. Events in which both planets are relatively massive (planet-star mass ratios of order $10^{-3}$), or in which the more massive planet occupies a favorable resonant configuration, produce strong central perturbations, resulting in detection efficiencies of roughly 90\%. By contrast, systems with only low-mass planets ($q \sim 10^{-4}$) or with less favorable alignments generate much weaker signals, which often fall below the detection threshold. In general, the planetary mass ratios and the resulting caustic geometry (e.g., central caustic size in resonant versus wide/close orbits) are the dominant factors governing detectability. Taking into account the expected frequency of planetary systems and the fraction of high-magnification events, we estimate that Roman will detect a high-magnification triple-lens event in approximately 4.5\% of multi-planet microlensing events, corresponding to about 64 events over the course of the full survey.

astro-ph.EP↗

arXiv2025

Probing Exotic Astrophysical Dark objects through Astrometric Microlensing from Gaia

We present the first comprehensive study of astrometric microlensing by exotic astrophysical dark objects, focusing on two theoretically motivated models -- Q-ball and boson star. We demonstrate that these extended objects generate distinctive signatures that depart markedly from point-mass lenses like primordial black holes. The smoking-gun signature for these exotic objects is the emergence of caustics, which form when the lens radius is below a critical threshold. Crossing these caustics induces discontinuous jumps in the images-centroid trajectory, a distinctive feature of these extended dark objects. We show these patterns are sensitive to the internal mass profile, with boson stars generating larger, more prominent caustic structures than Q-balls -- enabling the models to be distinguished. Using the Gaia DR3 stellar catalogue, we forecast a high-yield discovery potential, up to $\sim 6000$ detectable astrometric microlensing events for a 10-year mission, peaking for $M \sim 1-10~M_\odot$ and $R \lesssim 10~\text{AU}$. In the absence of anomalous detections, Gaia can set powerful 90% confidence level constraints on the fractional abundance of these exotic objects, reaching $f_{\mathrm{DM}} \le 10^{-3}$ in the peak region which covers masses from $10^{-1}-10^{7}~M_{\odot}$ and radii $R<10^{6}~\text{AU}$. Crucially, these projected astrometric microlensing constraints are significantly stronger than existing photometric microlensing limits in the $1-10~M_\odot$ mass range. This work establishes astrometric microlensing with Gaia as a powerful, complementary, and near-future probe with the potential to discover exotic astrophysical dark objects.

astro-ph.GA↗

arXiv2025

Predictions of the Nancy Grace Roman Space Telescope Galactic Exoplanet Survey. IV. Lens Mass and Distance Measurements

As part of the Galactic Bulge Time Domain Survey (GBTDS), the Nancy Grace Roman Galactic Exoplanet Survey (RGES) will use microlensing to discover cold outer planets and free-floating planets unbound to stars. NASA has established several science requirements for the GBTDS to ensure RGES success. A key advantage of RGES is Roman's high angular resolution, which will allow detection of flux from many host stars. One requirement specifies that Roman must measure the masses and distances of 40% of detected planet hosts with 20% precision or better. To test this, we simulated microlensing events toward the GBTDS fields and used Fisher matrix analysis to estimate light curve parameter uncertainties. Combining these with Roman imaging observables (lens flux, relative lens-source proper motion), we estimated the achievable precision of lens mass and distance measurements. Using pyLIMASS, a publicly available code for estimating lens properties, we applied this analysis to 3,000 simulated events. Assuming the Cassan et al. (2012) exoplanet mass function, we find that >40% of host stars meet the required 20% precision threshold, confirming that the GBTDS can satisfy the mission requirement. We validated our approach by comparing our inferred lens masses and distances to empirical measurements from detailed image-constrained light curve modeling of historical microlensing events with Hubble and Keck follow-up imaging. Our results agree within roughly 1 sigma, demonstrating that both approaches yield consistent and reliable mass and distance estimates, and confirming the robustness of our simulations for Roman-era microlensing science.

astro-ph.EP↗

arXiv2025

Can AI be Auditable?

Auditability is defined as the capacity of AI systems to be independently assessed for compliance with ethical, legal, and technical standards throughout their lifecycle. The chapter explores how auditability is being formalized through emerging regulatory frameworks, such as the EU AI Act, which mandate documentation, risk assessments, and governance structures. It analyzes the diverse challenges facing AI auditability, including technical opacity, inconsistent documentation practices, lack of standardized audit tools and metrics, and conflicting principles within existing responsible AI frameworks. The discussion highlights the need for clear guidelines, harmonized international regulations, and robust socio-technical methodologies to operationalize auditability at scale. The chapter concludes by emphasizing the importance of multi-stakeholder collaboration and auditor empowerment in building an effective AI audit ecosystem. It argues that auditability must be embedded in AI development practices and governance infrastructures to ensure that AI systems are not only functional but also ethically and legally aligned.

cs.CY↗

arXiv2025

The Future of Work is Blended, Not Hybrid

The way we work is no longer hybrid -- it is blended with AI co-workers, automated decisions, and virtual presence reshaping human roles, agency, and expertise. We now work through AI, with our outputs shaped by invisible algorithms. AI's infiltration into knowledge, creative, and service work is not just about automation, but concerns redistribution of agency, creativity, and control. How do we deal with physical and distributed AI-mediated workspaces? What happens when algorithms co-author reports, and draft our creative work? In this provocation, we argue that hybrid work is obsolete. Blended work is the future, not just in physical and virtual spaces but in how human effort and AI output become inseparable. We argue this shift demands urgent attention to AI-mediated work practices, work-life boundaries, physical-digital interactions, and AI transparency and accountability. The question is not whether we accept it, but whether we actively shape it before it shapes us.

cs.HC↗

arXiv2025

Effects of Superradiance in Active Galactic Nuclei

A supermassive black hole (SMBH) at the core of an active galactic nucleus (AGN) provides room for the elusive ultra-light scalar particles (ULSP) to be produced through a phenomenon called \textit{superradiance}. This phenomenon produces a cloud of scalar particles around the black hole by draining its spin angular momentum. In this work, we present a study of the superradiant instability due to a scalar field in the vicinity of the central SMBH in an AGN. We begin by showing that the time-evolution of the gravitational coupling $α$ in a realistic ambiance created by the accretion disk around the SMBH in AGN leads to interesting consequences such as the amplified growth of the scalar cloud, enhancement of the gravitational wave emission rate, and appearance of higher modes of superradiance within the age of the Universe. We then explore the consequence of superradiance on the characteristics of the AGN. Using the Novikov-Thorne model for an accretion disk, we divide the full spectrum into three wavelength bands- X-ray ($10^{-4}-10^{-2}~μ$m), UV (0.010-0.4~$μ$m), and Vis-IR (0.4-100~$μ$m) and observe sudden drops in the time-variations of the luminosities across these bands and Eddington ratio ($f_{\textrm{Edd}}$) with a characteristic timescale of superradiance. Using a uniform distribution of spin and mass of the SMBHs in AGNs, we demonstrate the appearance of depleted regions and accumulations along the boundaries of these regions in the planes of different band-luminosities and $f_{\textrm{Edd}}$. Finally, we discuss some possible signatures of superradiance that can be drawn from the observed time-variation of the AGN luminosities.

astro-ph.HE↗

arXiv2024

Microlensing Black Hole Shadows

A detailed analysis is presented of gravitational microlensing by intervening compact objects of the black hole shadows imaged by the Event Horizon Telescope (EHT). We show how the center, size, and shape of the shadow depend on the Einstein angle relative to the true/unlensed shadow size, and how the location of the lens affects the shift, size, and asymmetry of the black hole shadow due to microlensing. Assuming a supermassive black hole (SMBH) casts a circular-shaped true shadow, microlensing can create an asymmetry of up to approximately 8\%, which is twice the asymmetry caused by the SMBH's spin and its tilt relative to us. Furthermore, the size can be enhanced by $\sim$50\% of the true shadow. Currently, the terrestrial baselines of EHT lack the resolution to detect microlensing signatures in the shadows. However, future expansions of EHT, including space-based baselines at the Moon and L$_2$, could potentially enable the detection of microlensing events. For Sgr A$^*$, an event rate of 0.0014 per year makes the microlensing phenomena difficult to observe even with space-based baselines for the stellar population in the stellar bulge and stellar disk for lens masses $\sim M_\odot$. Nonetheless, the presence of a cluster of 20,000 stellar-mass black holes in the central parsec of the Milky Way, expected to arise from dynamical friction acting on infalling stellar clusters, significantly boosts the event rate. Hence, continuously monitoring the shadow of Sgr A$^*$ could offer novel insights into the compact object population surrounding the Galactic Center.

astro-ph.GA↗

arXiv2023

Toward Responsible AI Use: Considerations for Sustainability Impact Assessment

As AI/ML models, including Large Language Models, continue to scale with massive datasets, so does their consumption of undeniably limited natural resources, and impact on society. In this collaboration between AI, Sustainability, HCI and legal researchers, we aim to enable a transition to sustainable AI development by enabling stakeholders across the AI value chain to assess and quantitfy the environmental and societal impact of AI. We present the ESG Digital and Green Index (DGI), which offers a dashboard for assessing a company's performance in achieving sustainability targets. This includes monitoring the efficiency and sustainable use of limited natural resources related to AI technologies (water, electricity, etc). It also addresses the societal and governance challenges related to AI. The DGI creates incentives for companies to align their pathway with the Sustainable Development Goals (SDGs). The value, challenges and limitations of our methodology and findings are discussed in the paper.

cs.HC↗

arXiv2023

On the Effectiveness of Creating Conversational Agent Personalities Through Prompting

In this work, we report on the effectiveness of our efforts to tailor the personality and conversational style of a conversational agent based on GPT-3.5 and GPT-4 through prompts. We use three personality dimensions with two levels each to create eight conversational agents archetypes. Ten conversations were collected per chatbot, of ten exchanges each, generating 1600 exchanges across GPT-3.5 and GPT-4. Using Linguistic Inquiry and Word Count (LIWC) analysis, we compared the eight agents on language elements including clout, authenticity, and emotion. Four language cues were significantly distinguishing in GPT-3.5, while twelve were distinguishing in GPT-4. With thirteen out of a total nineteen cues in LIWC appearing as significantly distinguishing, our results suggest possible novel prompting approaches may be needed to better suit the creation and evaluation of persistent conversational agent personalities or language styles.

cs.HC↗

arXiv2023

EdgeP4: A P4-Programmable Edge Intelligent Ethernet Switch for Tactile Cyber-Physical Systems

Tactile Internet based operations, e.g., telesurgery, rely on end-to-end closed loop control for accuracy and corrections. The feedback and control are subject to network latency and loss. We design two edge intelligence algorithms hosted at P4 programmable end switches. These algorithms locally compute and command corrective signals, thereby dispense the feedback signals from traversing the network to the other ends and save on control loop latency and network load. We implement these algorithms entirely on data plane on Netronome Agilio SmartNICs using P4. Our first algorithm, $\textit{pose correction}$, is placed at the edge switch connected to an industrial robot gripping a tool. The round trip between transmitting force sensor array readings to the edge switch and receiving correct tip coordinates at the robot is shown to be less than $100~μs$. The second algorithm, $\textit{tremor suppression}$, is placed at the edge switch connected to the human operator. It suppresses physiological tremors of amplitudes smaller than $100~μm$ which not only improves the application's performance but also reduces the network load up to $99.9\%$. Our solution allows edge intelligence modules to seamlessly switch between the algorithms based on the tasks being executed at the end hosts.

cs.NI↗

arXiv2023

Astrometric Microlensing of Primordial Black Holes with Gaia

The Gaia space telescope allows for unprecedented accuracy for astrometric measurements of stars in the Galaxy. In this work, we explore the sensitivity of Gaia to detect primordial black hole (PBH) dark matter through the distortions that PBHs would create in the apparent trajectories of background stars, an effect known as astrometric microlensing (AML). We present a novel calculation of the lensing probability, and we combine this with the existing publicly released Gaia eDR3 stellar catalog to predict the expected rate of AML events that Gaia will see. We also compute the expected distribution of a few event observables, which will be useful for reducing backgrounds. Assuming that the astrophysical background rate of AML like events due to other sources is negligible, we then compute the potential exclusion that could be set on the parameter space of PBHs with a monochromatic mass function. We find that Gaia is sensitive to PBHs in the range of $0.4~M_\odot$ - $5\times10^7~M_\odot$, and has peak sensitivity to PBHs of $\sim 10~M_\odot$ for which it can rule out as little as a fraction $3\times10^{-4}$ of dark matter composed of PBHs. With this exquisite sensitivity, Gaia has the potential to rule out a PBH origin for the gravitational wave signals seen at LIGO/Virgo. Our novel calculation of the lensing probability includes for the first time, the effect of intermediate duration lensing events, where the lensing event lasts for a few years, but for a period which is still shorter than the Gaia mission lifetime. The lower end of our predicted mass exclusion is especially sensitive to this class of events. As and when time-series data for Gaia is released, and once we have a better understanding of the backgrounds, our prediction of the lensing rate and event observable distributions will be useful to estimate the true exclusion/discovery of the PBH parameter space utilizing this data.

astro-ph.GA↗

arXiv2022

Empowering Local Communities Using Artificial Intelligence

Artificial Intelligence (AI) is increasingly used to analyze large amounts of data in various practices, such as object recognition. We are specifically interested in using AI-powered systems to engage local communities in developing plans or solutions for pressing societal and environmental concerns. Such local contexts often involve multiple stakeholders with different and even contradictory agendas, resulting in mismatched expectations of these systems' behaviors and desired outcomes. There is a need to investigate if AI models and pipelines can work as expected in different contexts through co-creation and field deployment. Based on case studies in co-creating AI-powered systems with local people, we explain challenges that require more attention and provide viable paths to bridge AI research with citizen needs. We advocate for developing new collaboration approaches and mindsets that are needed to co-create AI-powered systems in multi-stakeholder contexts to address local concerns.

cs.AI↗