External Cloud Research Articles

Early warning signals indicate a critical transition in Betelgeuse

Context.Critical transitions occur in complex dynamical systems when the system dynamics undergoes a regime shift. These can often occur with little change in the mean amplitude of the system response prior to the actual time of transition. The recent dimming and brightening event in Betelgeuse occurred as a sudden shift in the brightness and has been the subject of much debate. Internal changes or an external dust cloud have been suggested as reasons for this change in variability.Aims.We examine whether the dimming and brightening event of 2019–20 could be due to a critical transition in the pulsation dynamics of Betelgeuse by studying the characteristics of the light curve prior to transition.Methods.We calculated the quantifiers hypothesized to rise prior to a critical transition for the light curve of Betelgeuse up to the dimming event of 2019–20. These included the autocorrelation at lag-1, variance, and the spectral coefficient calculated from detrended fluctuation analysis, in addition to two measures that quantify the recurrence properties of the light curve. Significant rises are confirmed using the Mann-Kendall trend test.Results.We see a significant increase in all quantifiers (p < 0.05) prior to the dimming event of 2019–20. This suggests that the event was a critical transition related to the underlying nonlinear dynamics of the star.Conclusions.Together with results that suggest a minimal change inTeffand IR flux, a critical transition in the pulsation dynamics might be a reason for the unprecedented dimming of Betelgeuse. The rise in the quantifiers we studied prior to the dimming event supports this possibility.

Effects of the external string cloud on the Van der Waals-like behavior and efficiency of AdS-Schwarzschild black holes in massive gravity

In this paper, we study AdS-Schwarzschild black holes in four and five dimensions in dRGT minimally coupled to a cloud of strings. It is observed that the entropy of the string cloud and massive terms does not affect the black hole entropy. The observations about four dimensions indicate that the massive term in the presence of external string cloud cannot exhibit Van der Waals-like behavior for AdS-Schwarzschild black holes and, therefore there is only the Hawking–Page phase transition. In contrast, in five dimensions, the graviton mass modifies this behavior through the third massive term, so that a critical behavior and second-order phase transition is deduced. Also, the Joule–Thomson effect is not observed. The black hole stability conditions are also studied in four and five dimensions and a critical value for the string cloud parameter is presented. In five dimensions a degeneracy between states for extremal black holes is investigated. After studying black holes as thermodynamic systems, we consider such systems as heat engines, and finally the efficiency of them is calculated.

Deep-learning approach to attack handling of IoT devices using IoT-enabled network services

The Internet of Things (IoT) is an emerging technology for network devices. Most IoT devices are enabled to connect to the Internet and to external cloud servers purposely or incidentally. It is likely that an attack goes into IoT devices or it is initiated by IoT devices, which is unless otherwise handled by security rules in the legacy network equipment. Since IoT devices may appear or disappear with no prior notification or no proper authentication, firewall rules set up in a legacy network are unsatisfactory to handle the IoT attacks. It is in part because the firewall rules in legal network are defined not only for legacy computing but also they should serve for IoT devices (see Fig. 1). This paper proposes an IoT-enabled network infrastructure, which is a complementary service to the legacy network infrastructure, to handle the packets coming into or going out of IoT devices only (see Fig. 2). Attack models in IoT devices are described in this paper. A few models can be detected by rulesets, while others may not be and therefore analyzed by an artificial neural network approach: IoT packet sequence patterns are trained; and potentially attackable packets are identified. The contribution of this paper includes 1) the characterization of IoT attacks, 2) the formation of neural network nodes to train the IoT attack models, and 3) embedding the trained models to analyze real-time network-streaming data.

Auditing in the Era of Big Data

Firms routinely manage their financial reporting systems on external cloud platforms that are susceptible to cyberattacks and data integrity issues. Therefore, the American Institute of Certified Public Accountants developed a special type of voluntary audit called a Service Organization Control audit (SOC audit) that evaluates this risk. This study conducts one of the first systematic analyses of the benefits and costs of these voluntary audits. Using hand-collected data from public firms, I find that (1) 29 percent of firms in the SP (2) business-model exposure to technology predicts a firm's decision to receive these audits; (3) the scope of these audits includes internal controls over data integrity; and (4) these audits are one of the largest predictors of the variation in audit-related fees, amounting to a $900,000 average annual increase in these fees at the firm level (by comparison, tax preparation fees average about $1.3 million). SOC audits are thus an important and concrete example of the broader social and governance mandates of new reporting frameworks, such as the ISSB's Value Reporting Framework and FASB's ESG framework.

Federation of compute resources available to the German CMS community

The German CMS community (DCMS) as a whole can benefit from the various compute resources, available to its different institutes. While Grid-enabled and National Analysis Facility resources are usually shared within the community, local and recently enabled opportunistic resources like HPC centers and cloud resources are not. Furthermore, there is no shared submission infrastructure available.Via HTCondor’s [1] mechanisms to connect resource pools, several remote pools can be connected transparently to the users and therefore used more efficiently by a multitude of user groups. In addition to the statically provisioned resources, also dynamically allocated resources from external cloud providers as well as HPC centers can be integrated. However, the usage of such dynamically allocated resources gives rise to additional complexity. Constraints on access policies of the resources, as well as workflow necessities have to be taken care of. To maintain a well-defined and reliable runtime environment on each resource, virtualization and containerization technologies such as virtual machines, Docker, and Singularity, are used.

Extended ionized-gas structures in Seyfert 2 galaxy Mrk 78

Search for and study of extended emission-line regions (EELRs) related to AGN in early-type galaxies is interesting to probe the history of nuclear ionization activity and also to understand the process of external gas accretion. In this work, we present observations of the EELR in Mrk 78 obtained at the 6-m Russian telescope using the long-slit and 3D spectroscopy methods. We show that ionized-gas clouds at the 12-16 kpc projected distances from the nucleus are ionized by the AGN radiation. Also we have checked if the galaxy appearing in the optical images in the immediate neighbourhood of Mrk 78 near the external clouds is a dwarf companion or a part of a tidal structure. However, the spectrum of this galaxy, SDSS J074240.37+651021.4, obtained at the 6-m telescope corresponds to the distant background galaxy.

Critical behavior of AdS Gauss\u2013Bonnet massive black holes in the presence of external string cloud

Following previous study about AdS-Schwarzschild black holes minimally coupled to a cloud of strings in the context of massive gravity (Ghanaatian et al. in Effects of the external string cloud on the Van der Waals like behavior and efficiency of AdS-Schwarzschild black hole in massive gravity, arXiv:1906.00369 [hep-th]) and inspired by strong connection between Gauss–Bonnet Gravity and heterotic string theory, in this paper, we first take into account the Gauss–Bonnet term and we study thermodynamics and critical behavior of these black holes in the extended phase space. The effects of Gauss–Bonnet, massive, and string cloud parameters on the criticality of these black holes has been investigated. It can be seen that the Gauss–Bonnet and massive parameters have opposite effects on the criticality and phase transition of the solutions. We also observe that the increase in the value of the string cloud parameter above a critical value, eliminates the van der Waals like behavior of these solutions. Also, the Joule–Thomson effect is not observed. Then we examine thermal stability of these black holes in canonical ensemble by calculating the heat capacity. In addition, we explore critical behavior in extended phase space by employing heat capacity and consequently, we observe that the results are in agreement with the previous results from the usual method in Sect. 3.

Running HTC and HPC applications opportunistically across private, academic and public clouds

The Fusion Science Demonstrator in the European Open Science Cloud for Research Pilot Project aimed to demonstrate that the fusion community can make use of distributed cloud resources. We developed a platform, Prominence, which enables users to transparently exploit idle cloud resources for running scientific workloads. In addition to standard HTC jobs, HPC jobs such as multi-node MPI are supported. All jobs are run in containers to ensure they will reliably run anywhere and are reproduceable. Cloud infrastructure is invisible to users, as all provisioning, including extensive failure handling, is completely automated. On-premises cloud resources can be utilised and at times of peak demand burst onto external clouds. In addition to the traditional “cloud-bursting” onto a single cloud, Prominence allows for bursting across many clouds in a hierarchical manner. Job requirements are taken into account, so jobs with special requirements, e.g. high memory or access to GPUs, are sent only to appropriate clouds. Here we describe Prominence, its architecture, the challenges of using many clouds opportunistically and report on our experiences with several fusion use cases.

The Nuclear Filaments inside the Circumnuclear Disk in the Central 0.5 pc of the Galactic Center

Abstract We present CS(7–6) line maps toward the central parsec of the Galactic center, conducted with the Atacama Large Millimeter/submillimeter Array. The primary goal is to find and characterize the gas structure in the inner cavity of the circumnuclear disk (CND) in high resolution (1.″3 = 0.05 pc). Our large field-of-view mosaic maps—combining interferometric and single-dish data that recover extended emission—provide a first homogeneous look to resolve and link the molecular streamers in the CND with the neutral nuclear filaments newly detected within the central cavity of the CND. We find that the nuclear filaments are rotating with Keplerian velocities in a nearly face-on orbit with an inclination angle of ∼10°–20° (radius ≤ 0.5 pc). This is in contrast to the CND which is highly inclined at ∼65°–80° (radius ∼2–5 pc). Our analysis suggests a highly warped structure from the CND to the nuclear filaments. This result may hint that the nuclear filaments and the CND were created by different external clouds passing by Sgr A*.

Multiqueue Scheduling of Heterogeneous Tasks With Bounded Response Time in Hybrid Green IaaS Clouds

Cost-effective task scheduling is an important operation in green infrastructure-as-a-service clouds (GICs) as the energy consumed by users’ tasks is drastic. The irregular task arrival forces private GIC to adopt hybrid clouds to outsource some tasks to dynamic and reliable virtual machines (VMs) of public external clouds. However, temporal differences in revenue, electricity prices, wind and solar energy, and VM running prices of public external clouds make it difficult to dispatch all tasks in a cost-effective way while satisfying users’ specified response time constraints. Unlike existing methods, we propose a multiqueue scheduling (MQS) method that investigates such temporal differences in hybrid GICs (HGICs). Specially, this work first gives mathematical relations between rejected tasks and service rates of servers in private GIC. In each iteration of MQS, this paper formulates a profit maximization problem for HGIC and solves it by a novel meta-heuristic optimization method by combing simulated annealing, particle swarm optimization, and genetic algorithm. Trace-driven experiments based on real-life data demonstrate that profit and throughput of MQS are larger than typical task scheduling algorithms while meeting tasks’ response time constraints.

External and internal cloud condensation nuclei (CCN) mixtures: controlled laboratory studies of varying mixing states

Abstract. Changes in aerosol chemical mixtures modify cloud condensation nuclei (CCN) activity. Previous studies have developed CCN models and validated changes in external and internal mixing state with ambient field data. Here, we develop an experimental method to test and validate the CCN activation of known aerosol chemical composition with multicomponent mixtures and varying mixing states. CCN activation curves consisting of one or more activation points are presented. Specifically, simplified two-component systems of varying hygroscopicity were generated under internal, external, and transitional mixing conditions. κ-Köhler theory predictions were calculated for different organic and inorganic mixtures and compared to experimentally derived kappa values and respective mixing states. This work employs novel experimental methods to provide information on the shifts in CCN activation data due to external to internal particle mixing from controlled laboratory sources. Results show that activation curves consisting of single and double activation points are consistent with internal and external mixtures, respectively. In addition, the height of the plateau at the activation points is reflective of the externally mixed concentration in the mixture. The presence of a plateau indicates that CCN activation curves consisting of multiple inflection points are externally mixed aerosols of varying water-uptake properties. The plateau disappears when mixing is promoted in the flow tube. At the end of the flow tube experiment, the aerosols are internally mixed and the CCN activated fraction data can be fit with a single-sigmoid curve. The technique to mimic externally to internally mixed aerosol is applied to non-hygroscopic carbonaceous aerosol with organic and inorganic components. To our knowledge, this work is the first to show controlled CCN activation of mixed non-hygroscopic soot with hygroscopic material as the aerosol population transitions from externally to internally mixed states in laboratory conditions. Results confirm that CCN activation analysis methods used here and in ambient data sets are robust and may be used to infer the mixing state of complex aerosol compositions of unknown origin.

Modular phenomenological model for vented explosions and its validation with experimental and computational results

The present study reports a modular phenomenological model for predicting peak pressure in vented explosions. Modelling assumptions are explained in detail and model components are validated against experimental and computational results. A basic version of this model is reported in our earlier paper (Sinha et al., 2019). Previous experimental and modelling efforts on vented explosion have primarily focussed on idealized condition of empty container with uniformly mixed fuel. However, in real accidents, there are often obstacles in flame path, and a leaked fuel may not get enough time to mix uniformly. These realistic accidental scenarios are accounted for in this extended model. First the model components are assessed using available experimental results. Comparison of flame arrival time and flame propagation inside the enclosure are made, which demonstrate the ability of the model to capture flame propagation accurately. Suggestions are also made for vent panel installation to reduce peak overpressure in accidental explosions.Predictions for external cloud radius and pressure generated by external explosion are found to be in close agreement with the experimentally measured values. The model is further simplified, and a final equation is proposed which depends on two fuel related parameters and two geometric parameters. Fuel dependent parameters are pre-tabulated, and geometric parameters are easy to compute. Procedure to calculate pressure generated by external explosion and internal pressure are outlined in detail. Experimental results available in literature are used to evaluate model predictive capabilities. The model, in principle should be applicable for any gaseous fuel. However, the focus of the present investigation is to assess it for hydrogen explosions. Experimental repeatability is also discussed, and role of wall deflection is highlighted.In parallel to the modelling effort, a dedicated in-house CFD solver HyFOAM is developed utilizing OpenFOAM platform. The HyFOAM predictions are validated against experimental results from the recently published test data involving hydrogen explosion in a 20-foot ISO container (Skjold et al., 2017, 2018, 2019). Moreover, as experimental investigations are expensive and require significant testing and safety infrastructure, a limited number of scenarios can be tested experimentally. In addition to the experimental results, few more cases are simulated using HyFOAM. Phenomenological model results are compared with the CFD results, and a reasonably good match is observed.

Recommending heterogeneous resources for science gateway applications based on custom templates composition

Abstract Emerging interdisciplinary data-intensive science gateway applications in engineering fields (e.g., bioinformatics, cybermanufacturing) demand the use of high-performance computing resources. However, to mitigate operational costs and management efforts for these science gateway applications, there is a need to effectively deploy them on federated heterogeneous resources managed by external Cloud Service Providers (CSPs). In this paper, we present a novel methodology to deliver fast, automatic and flexible resource provisioning services for such application-owners with limited expertise in composing and deploying suitable cloud architectures. Our methodology features a Component Abstraction Model to implement intelligent resource ‘abstractions’ coupled with ‘reusable’ hardware and software configuration in the form of “custom templates” to simplify heterogeneous resource management efforts. It also features a novel middleware that provides services via a set of recommendation schemes for a context-aware requirement-collection questionnaire. Recommendations match the requirements to available resources and thus assist novice and expert users to make relevant configuration selections with CSP collaboration. To evaluate our middleware, we study the impact of user preferences in requirement collection, jobs execution and resource adaptation for a real-world manufacturing application on Amazon Web Services and the GENI cloud platforms. Our experiment results show that our scheme improves the resource recommendation accuracy in the manufacturing science gateway application by up to 21% compared to the existing schemes. We also show the impact of custom templates knowledgebase maturity at the CSP side for handling novice and expert user preferences in terms of the resource recommendation accuracy.

The Nucleon Resonance Structure from the π+π−p Electroproduction Reaction off Protons

The data on photo- and electroexcitation amplitudes of most nucleon resonances in the mass range up to 2.0 GeV determined from the CLAS experiments on exclusive π+π−p photo-electroproduction off protons in collaboration between the Jefferson Lab and Moscow State University are presented. The first (and, currently, the only available) data on electroexcitation amplitudes from CLAS in a wide range of photon virtualities Q2 <5.0 GeV2 reveal the nucleon resonance structure as a complex interplay between the inner core of three dressed quarks and an external meson-baryon cloud. These results shed light on the strong QCD dynamics, which underlies the generation of excited nucleon states with different structural features from confined quarks and gluons. The future prospects of these studies in the new era of experiments with the CLAS 12 detector, which began in the spring of 2018, are outlined.

A debris cloud model for hypervelocity impact of the spherical projectile on reactive material bumper composed of polytetrafluoroethylene and aluminum

In this paper, a debris cloud model is presented for the case of hypervelocity impact of the spherical projectile on the thin PTFE (polytetrafluoroethylene)/Al (aluminum) reactive material bumper at normal incidence. The experiments of projectiles with hypervelocity impact on Whipple shields with PTFE/Al and Al2024 as bumper respectively were carried out by using two-stage light-gas gun, and the movement process of debris cloud was recorded through laser shadow photography system. According to the numerical simulation results and the laser shadow photographs of debris cloud obtained from the experiment of hypervelocity impact, two parts named as internal and external debris cloud are considered in the theoretical model. Several assumptions are made, and the theoretical model of debris cloud is developed by the conservation laws of mass, momentum and energy. Four characteristic velocities of the debris cloud are first calculated, and thus the whole evolution process of the debris cloud is plotted according to those velocities. By comparing the size of the debris cloud shown in the experiment, it can be concluded that the theoretical model agrees well with the experimental results. Moreover, the characteristic velocities of projectile fragments and bumper fragments in the debris cloud are calculated, and the mass areal density and momentum areal density distribution of the debris cloud on the rear wall are also obtained. Additionally, the effects of the detonation reaction of the reactive material bumper on the projectile during the impact are analyzed in contrast with the results on the Al2024 bumper. It is indicated that the detonation reaction of PTFE/Al can reduce the velocity of center of mass of debris cloud and increase the expansion velocity of debris cloud. PTFE/Al bumper can reduce damage caused by debris cloud to rear wall.

The Green Bank Ammonia Survey: A Virial Analysis of Gould Belt Clouds in Data Release 1

Abstract We perform a virial analysis of starless dense cores in three nearby star-forming regions: L1688 in Ophiuchus, NGC 1333 in Perseus, and B18 in Taurus. Our analysis takes advantage of comprehensive kinematic information for the dense gas in all of these regions made publicly available through the Green Bank Ammonia Survey Data Release 1, which is used to estimate internal support against collapse. We combine this information with ancillary data used to estimate other important properties of the cores, including continuum data from the James Clerk Maxwell Telescope Gould Belt Survey for core identification, core masses, and core sizes. Additionally, we used Planck- and Herschel-based column density maps for external cloud weight pressure and Five College Radio Astronomy Observatory 13CO observations for external turbulent pressure. Our self-consistent analysis suggests that many dense cores in all three star-forming regions are not bound by gravity alone, but rather require additional pressure confinement to remain bound. Unlike a recent, similar study in Orion A, we find that turbulent pressure represents a significant portion of the external pressure budget. Our broad conclusion emphasizing the importance of pressure confinement in dense core evolution, however, agrees with earlier work.

Implementation and Performance Analysis of Private Cloud Using Openstack Swift and Rclone

Many companies need a storage system that can be accessed in real time by all parts of the company. Most digital data storage methods today still use conventional methods where data is stored on an external hard disk or public cloud. Storage with external hard disk media makes accessing data difficult and has the risk of data loss when storage media is damaged. On the other hand, the storage method using public cloud requires an internet connection with large bandwidth requirements and the company still has to spend a budget on renting it. This study aims to design digital data storage methods using a private cloud that can be accessed in real time by all parts of the company without having to spend a budget on hiring a storage media and renting an internet connection with large bandwidth requirements. A private cloud was built using OpenStack Swift as an object storage service provider and Rclone as a cross-platform computer data management application. The results of this study are the creation of a private cloud that runs object storage services using Swift storage objects with relatively light and high scalability to meet the needs of storing data effectively and efficiently. A private cloud-based data storage media with relatively light and high scalability to meet data storage needs. Data storage media that can be accessed easily without having to use an internet connection with large bandwidth requirements.

Electromagnetic form factors of nucleon resonances from CLAS

Exclusive single and double meson photo- and electroproduction reactions are the largest sources of information on the spectrum and structure of nucleon resonances. The excited states of the nucleon manifest as a complex interplay between the inner core of three dressed quarks and the external meson-baryon cloud. Various N* with distinctively different structure appear as unique laboratory where many features of strong QCD can be explored. With combination of nearly 4π acceptance of the CLAS detector and continuous electron beam (Jefferson Lab, USA) it is possible to obtain physics observables of the major reaction channels in the N* excitation region. The results on the electromagnetic transition form factors of N(1440)1/2+ and N(1520)3/2- are presented.

Experimental analysis and comparative study of secure data outsourcing schemes in cloud

When customers are transferring their private data to any third party, then there is much responsibility of both security and compliance. The outsourcing process is computationally secure if it is performed without unveiling to the other external agent or cloud, either the original data or the actual solution to the computations. Secure multiparty computation computes a certain function without revealing their private secret information. Homomorphic encryption is another solution that can deal with this situation. In homomorphic encryption, ciphertext (data in encrypted format) should be sent to the cloud, the computations are made on the ciphertext, and the result of this computation is a ciphertext form itself. If the result of the computation is decrypted, then the correct plaintext result must be obtained. In this paper, we summarised our proposed secure outsourcing computing protocols. As a cloud application, our proposed protocols encrypt data by different users and further are transformed to cloud. By utilising our protocols, we performed experimental analysis on virtual cloud to examine the novelty in terms of computational and communication complexity. Our implementations involve both CPU and GPU-based simulation results. We improved our adopted procedure to achieve better speed-up and security.

Comprehensive Survey of Galvanic Coupling and Alternative Intra-Body Communication Technologies

Fundamental understanding of the processes that affect the state and well being of the human body continues to be a challenging frontier. Recent technological developments point toward the possibility of implanting sensors inside the body, thus enabling in-situ data gathering and real-time actuation with the transmission of the sensed data to other implants as well as external computational clouds. This paper aims to survey and compare the existing methods for achieving intra-body communication (IBC) covering the methods of galvanic coupling (waveguide-based), capacitive coupling (electric field-based), ultrasound (acoustic-based) and magnetic resonant coupling (magnetic field-based). The performance of each method is evaluated in terms of its physical layer characteristics, including operating frequency range, attenuation effects within the body, channel modeling methods, power consumption, achievable data rates, communication distance, and safety limits under prolonged signal exposure. Based on this metric-driven study, we identify specific scenarios where one or more of these different IBC methods are better suited. For the specific case of galvanic coupling, we provide select system designs, experimental results from a custom-designed testbed and target applications that are more appropriate for this method of IBC. To the best of our knowledge, this is the first work that encapsulates the state of the art and current research trends for several different types of IBC solutions, a topic that promises to revolutionize the future of healthcare.