Adapt then Unlearn: Exploiting Parameter Space Semantics for Unlearning in Generative Adversarial Networks

The increased attention to regulating the outputs of deep generative models, driven by growing concerns about privacy and regulatory compliance, has highlighted the need for effective control over these models. This necessity arises from instances where generative models produce outputs containing undesirable, offensive, or potentially harmful content. To tackle this challenge, the concept of machine unlearning has emerged, aiming to forget specific learned information or to erase the influence of undesired data subsets from a trained model. The objective of this work is to prevent the generation of outputs containing undesired features from a pre-trained GAN where the underlying training data set is inaccessible. Our approach is inspired by a crucial observation: the parameter space of GANs exhibits meaningful directions that can be leveraged to suppress specific undesired features. However, such directions usually result in the degradation of the quality of generated samples. Our proposed method, known as 'Adapt-then-Unlearn,' excels at unlearning such undesirable features while also maintaining the quality of generated samples. This method unfolds in two stages: in the initial stage, we adapt the pre-trained GAN using negative samples provided by the user, while in the subsequent stage, we focus on unlearning the undesired feature. During the latter phase, we train the pre-trained GAN using positive samples, incorporating a repulsion regularizer. This regularizer encourages the model's parameters to be away from the parameters associated with the adapted model from the first stage while also maintaining the quality of generated samples. To the best of our knowledge, our approach stands as first method addressing unlearning in GANs. We validate the effectiveness of our method through comprehensive experiments.Comment: 15 pages, 12 figure

Uzbuda autoionizacijskog stanja u Na udarom elektrona

Electron-impact integral cross sections for the excitation of the lowest lying autoionizing level generated by the inner-shell 1s2 2s2 2p6 3s 2S e → 1s2 2s2 2p5 3s2 2P 0 complex transition in sodium (Na) atomic system have been calculated. In the calculation, single-configuration Hartree-Fock (HF) wave functions for both initial and final states involved in the transition matrix element within the asymptotic Green function approximation (AGFA) proposed by Tiwary (1981) were employed. The calculation was done exactly in the same way as in the earlier work in the case of the lightest alkali-metal atom lithium (Tiwary (1985), Tiwary, Macek and Madison (1985)) and the heaviest alkali-metal atom caesium (Tiwary (1983)) in the bombarding energy range from the threshold to 1500 eV. For the first time, Tiwary (1983) predicted the resonance behaviour in near vicinity of the excitation threshold in Cs using AGFA. Feuerstein et al. (1998) performed the experiment and observed resonance behaviour in the neighbourhood of excitation threshold in Na. Comparison has been made with available relevant experimental observations and other theoretical predictions. Our present AGFA theoretical result is qualitatively in accord with the experimental results.Izračunali smo integralne udarne presjeke za uzbudu najnižeg autoionizacijskog stanja koje nastaje udarom elektrona te putem kompleksnog prijelaza 1s2 2s2 2p6 3s 2S e Q 1s2 2s2 2p5 3s2 2P 0 među unutarnjim ljuskama u atomima natrija. U računu smo primijenili jedno-konfiguracijske Hartree-Fockove (HF) valne funkcije za odnosna početna i konačna stanja u matričnom elementu unutar asimptotskog približenja za Greenove funkcije (AGFA), predloženog Tiwary-em (1981). Račun je proveden točno na način kao u ranijem radu za najlakši alkalijski metalni atom litij (Tiwary (1985), Tiwary, Macek and Madison (1985)) i najteži alkalijski metalni atom cezij (Tiwary (1983)), za energije elektrona od praga do 1500 eV. Tiwary (1983) je prvi predvidio rezonanciju blizu iznad uzbudnog praga u Cs primjenom AGFA-e. Feuerstein et al. (1998) izveli su mjerenja i vidjeli rezonanciju u blizini uzbudnog praga u Na. Načinili smo usporedbu poznatih eksperimentalnih podataka i drugih teorijskih predviđanja. Naši su sadašnji teorijski rezultati u skladu s eksperimentalnima

Analytic many-body potential for GaAs(001) homoepitaxy: Bulk and surface properties

We employ atomic-scale simulation methods to investigate bulk and surface properties of an analytic Tersoff- Abell type potential for describing interatomic interactions in GaAs. The potential is a modified form of that proposed by Albe and colleagues [Phys. Rev. B 66, 035205 (2002)] in which the cut-off parameters for the As-As interaction have been shortened.With this modification, many bulk properties predicted by the potential for solid GaAs are the same as those in the original potential, but properties of the GaAs(001) surface better match results from first-principles calculations with density-functional theory (DFT). We tested the ability of the potential to reproduce the phonon dispersion and heat capacity of bulk solid GaAs by comparing it to experiment and the overall agreement is good. In the modified potential, the GaAs(001) β2(2 × 4) reconstruction is favored under As-rich growth conditions in agreement with DFT calculations. Additionally, the binding energies and diffusion barriers for a Ga adatom on the β2(2 × 4) reconstruction generally match results from DFT calculations. These studies indicate that the potential is suitable for investigating aspects of GaAs(001) homoepitaxy

Comparison of methods for evaluating the suitability of Vertisols for Gossypium hirsutum (Bt cotton) in two contrasting agro-ecological regions

This is the author accepted manuscript. The final version is available from Taylor and Francis (Routledge) via the DOI in this record.Cotton (Gossypium sp.) is a major crop grown under rainfed conditions in Vertisols and associated soils in semi-arid tropical (SAT) regions of Peninsular India. In recent years, cotton productivity has declined due to various biophysical factors including pest and diseases, seasonal water stress soil degradation and poor crop management practices. In this study, we compare two methods for evaluating the suitability of Vertisols for cotton in contrasting two agro-ecological regions viz., sub-humid moist (SHM) region and semi-arid dry(SAD) were characterized. Twelve cotton growing Vertisols (seven from SHM and five from SAD) were evaluated for their suitability for cotton cultivation using soil quality index (SQI) and modified Sys-FAO method. SQIs were calculated using the weighted additive index from transformed scores of selected indicators by principal component analysis. For Sys-FAO method both biophysical and soil characteristics were considered for suitability evaluation. We found that the soils of SHM region were moderately suitable for cotton cultivation with soil moisture as the major limiting factor, whereas the soils of SAD region are marginally suitable due to high exchangeable sodium percentage and poor hydraulic conductivity. From this, it may be concluded that the weighted SQI has better agreement with the cotton yield

Cytokines induce effector T-helper cells during invasive aspergillosis; what we have learned about T-helper cells?

Invasive aspergillosis caused by Aspergillus species (Aspergillus fumigatus, A. flavus and A. terreus) is life-threatening infections in immunocompromised patients. Understanding the innate and adaptive immune response particularly T-helper cells (TH-cells) against these Aspergillus species and how the different sub-set of TH-cells are regulated by differentiating cytokines at primary target organ site like lung, kidney and brain is of great significance to human health. This review focuses on presentation of Aspergillus through Antigen presenting cells (APCs) to the naive CD4+ T-cells in the host. The production of differentiating/effector cytokines that activate following TH-cells e.g., TH1, TH2, TH9 and TH17 has been reported in association or alone in allergic or invasive aspergillosis. Chemokines (CXCL1, CXCL2, CCL1 and CCL20) and their receptors associated to these TH-cells have also been observed in invasive aspergillosis. Thus, further study of these TH-cells in invasive aspergillosis and other elements of adaptive immune response with Aspergillus species are required in order to have a better understanding of host response for safer and effective therapeutic outcome

Stress concentration targeted reinforcement using multi-material based 3D printing

Topological engineering (3D printing into complex geometry) has emerged as a pragmatic approach to develop high specific strength (high strength and low density) lightweight structures. These complex lightweight structures fail at high-stress concentration regions, which can be, replaced with soft/tough material using 3D printing. It can improve mechanical properties such as strength, toughness and energy absorption etc. Here, we have developed stress concentration targeted multi-material schwarzite structures by 3D printing technique. The soft (Thermoplastic Polyurethane) material is reinforced at high-stress concentration regions of hard (Polylactic acid) schwarzite structures to enhance the specific yield strength and resilience. The mechanical properties and responses of these structures were then assessed via uniaxial compression tests. The multi-materials 3D printed composite structure shows improved mechanical properties compared to single materials architecture. The specific resilience of composites demonstrates remarkable enhancements, with percentage increases of 204.70 %, 596.50 %, and 1530.99 % observed when compared to hard primitives, and similarly impressive improvements of 182.45 %, 311.64 %, and 477.75 % observed in comparison to hard gyroids. The obtained experimental findings were comprehensively examined and validated with molecular dynamics (MD) simulations. The promising characteristics of these lightweight multi-material-based Schwarzites structures can be utilized in various fields such as energy harvesting devices, protective, safety gears, and aerospace components

STRUCTURAL AND OPTICAL PROPERTIES OF ZnS NANOPARTICLES SYNTHESIZED BY MICROWAVE IRRADIATION METHOD

ZnS nanoparticles were synthesized by Microwave assisted irradiation method. The obtained ZnS nanoparticles were characterized by XRD, SEM and UV-Vis spectroscopy. XRD characterization of the samples were taken which verify the crystalline form of the samples and also the average size of the nanocrystallites were measured by DebyeScherrer formula as per the XRD spectrum, which was found to be around 6 nm. The surface morphology of the ZnS nanocrystallites was taken by Scanning Electron Microscopy. The UV-Visible absorption spectra of the nanocrystallites were taken and the optical bandgap of the ZnS nanocrystals were found to be 3.76 eV