Degeneration-Tuning: Using Scrambled Grid shield Unwanted Concepts from Stable Diffusion

Owing to the unrestricted nature of the content in the training data, large text-to-image diffusion models, such as Stable Diffusion (SD), are capable of generating images with potentially copyrighted or dangerous content based on corresponding textual concepts information. This includes specific intellectual property (IP), human faces, and various artistic styles. However, Negative Prompt, a widely used method for content removal, frequently fails to conceal this content due to inherent limitations in its inference logic. In this work, we propose a novel strategy named \textbf{Degeneration-Tuning (DT)} to shield contents of unwanted concepts from SD weights. By utilizing Scrambled Grid to reconstruct the correlation between undesired concepts and their corresponding image domain, we guide SD to generate meaningless content when such textual concepts are provided as input. As this adaptation occurs at the level of the model's weights, the SD, after DT, can be grafted onto other conditional diffusion frameworks like ControlNet to shield unwanted concepts. In addition to qualitatively showcasing the effectiveness of our DT method in protecting various types of concepts, a quantitative comparison of the SD before and after DT indicates that the DT method does not significantly impact the generative quality of other contents. The FID and IS scores of the model on COCO-30K exhibit only minor changes after DT, shifting from 12.61 and 39.20 to 13.04 and 38.25, respectively, which clearly outperforms the previous methods

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

Energy conversion efficiency improvement and NOx emission reduction study of different shaped micro-combustors.

This work mainly investigates the effects of factors, such as internal structure, combustor shape, porous medium on the thermal performance and energy conversion efficiency of micro- combustors. In addition, the feasibility of replacing traditional hydrocarbon fuel with ammonia gas is also analysed to reduce NOx emission without affecting the combustion efficiency. The main work and innovations of this paper are as follows: 3D numerical simulations are conducted on a hydrogen-fuelled micro-combustor with ring-shaped ribs to achieve a more uniform and higher wall temperature. The effects of rib shape, rib location, inlet velocity and the equivalence ratio are evaluated. The numerical model is built with a standard k-ε turbulence model and EDC (eddy dissipation concept) chemical reaction model. These models are validated before being applied to study 3 different ribs with a cross-sectional view of 1) rectangular, 2) Ո-shaped and 3) Ս-shaped (defined basing on the bottom rib). It is found that the optimum design is the Ս-shaped ribs, since the mean wall temperature is increased by 25.4 K in comparison with other designs. Further analysis is conducted on entropy production due to chemical reactions and heat transfer processes. It is found that the chemical reaction and the heat conduction contribute 70% and 15% of the total entropy generation respectively. Furthermore, the thermodynamic 2nd-law efficiency remains in the range of 46%-51% when the equivalence ratio varies from 0.8 to 1.2. A micro-combustor with a tailored internal thread is proposed to uniform the wall temperature and improve the 2nd-law efficiency of micro thermophotovoltaic system. The effects of the thread form, inlet velocity and nominal diameter on the thermal performance are investigated by performing computational fluid dynamics simulations. Results indicate that the application of corrugated thread structures can reduce the flame temperature and enhance heat transfer remarkably. In addition, the mean wall temperature and standard deviation of wall temperature both increase distinctively with the increase of nominal diameter. Moreover, the 2nd-law efficiency of the triangular thread is above 65% while the entropy production from chemical reaction and heat conduction contributes more than 80%. Thermal performances and emitter efficiency assessments of two proposed unconventional micro-combustors, i.e. T- and Y-shaped are both experimentally and numerically conducted. Comparison is then made between the proposed combustion systems with the conventional I-shaped micro-combustor fuelled by premixed CH₄/O₂/Ar. The effects of mass flow rate, equivalence ratio, extending depth of flame holder and porous medium are numerically evaluated using 3D models with structured meshes. It is found that the bifurcation structure (T- and Y-shaped) will reduce the expanding area of high temperature at inlet and prevent the wall temperature from dropping too fast downstream. Besides, the best thermal performance is achieved when the extending depth of flame holder is 2.0 mm. The T-shaped combustor occupies the highest radiation efficiency of 39.4% when the length of porous medium is 8 mm and ̇ = 4.8×10⁻⁶ kg/s. In order to reduce NOx emission at the premise of guaranteeing energy conversion efficiency, three micro-combustors with different ring-shaped ribs in a cross-sectional view of 1) rectangular, 2) Ո-shaped and 3) Ս-shaped are proposed and fuelled by NH₃. Extensive numerical comparisons are made with 3D models built by structured mesh. The effects of inlet velocity, equivalence ratio, rib shape and porous medium on combustion efficiency and NOx emission are evaluated. In addition, the normalized sensitivity of NO formation and related reaction pathways are analysed. It is found that the double-rib structure is more conducive to achieving better thermal performance. Besides, HNO is found to contribute the most of NO production while NH and NH₂ are beneficial to the consumption of NO. When the dimensionless distance x between the rib and inlet is 3/9, NO emission is reduced by 47.0% while the radiation efficiency is only decreased by 1.76% when the equivalence ratio increases from 1 to 1.1. Besides, with the increased thermal conductivity of porous materials, the MWT drops slightly and then rises obviously. Besides, the emission of NO is decreased by 99.98% from 2.70×10⁴ ppm to 5.17 ppm, while the emission of N₂O is increased by 100 times from 24.8 ppm to 2.52×10³ ppm

Numerical Investigation of Inlet Thermodynamic Conditions on Solid Fuel Ramjet Performances

In this work, 2D numerical RANS (Reynolds Average Navier-Stokes) simulations were carried out to investigate the thermodynamic performance of a solid fuel ramjet (SFRJ) with different inlet conditions. This is achieved by using an in-house FORTRAN code to simulate a 2D turbulent, reacting, unsteady flow in the ramjet engine. The inlet conditions are characterized by three key parameters: (1) swirl number (SN), (2) mass flow rate (ṁair), and (3) inlet temperature (Tin). With the code numerically validated by benchmarking with a number of computed cases, it is applied to perform systematic studies on the turbulent flow recirculation, combustion, and heat transfer characteristics. It is found that increasing SN, ṁair, or Tin can dramatically enhance the combustion heat release rate, regression rate, and combustor average temperature. Furthermore, the analysis on the chemical reaction intermediate (CO) reveals that the chemical reaction is more sufficient with increased ṁair, but SN=0. In addition, a secondary vortex is generated at the corner of the backward facing step in the presence of a swirl flow resulting from the instability of the shear layer. Finally, the nonlinear correlations between the heat transfer, combustion characteristics, and flow field characteristics and the corresponding inlet thermodynamic parameters are identified

Continual Vision-Language Representation Learning with Off-Diagonal Information

Large-scale multi-modal contrastive learning frameworks like CLIP typically require a large amount of image-text samples for training. However, these samples are always collected continuously in real scenarios. This paper discusses the feasibility of continual CLIP training using streaming data. Unlike continual learning based on self-supervised learning methods for pure images, which is empirically robust against catastrophic forgetting, CLIP's performance degeneration in the continual setting is significant and non-neglectable. By analyzing the changes in the model's representation space during continual CLIP training from a spatial geometry perspective, we explore and summarize these spatial variations as Spatial Disorder (SD), which can be divided into Intra-modal Rotation and Inter-modal Deviation. Moreover, we empirically and theoretically demonstrate how SD leads to a performance decline for CLIP on cross-modal retrieval tasks. To alleviate SD, we propose a new continual vision-language representation learning framework Mod-X: Maintain off-diagonal information-matriX. By selectively aligning the off-diagonal information distribution of contrastive matrices, the Mod-X improves the capability of the multi-modal model by maintaining the multi-modal representation space alignment on the old data domain during continuously fitting the new training data domain. Experiments on commonly used datasets with different scales and scopes have demonstrated the effectiveness of our method

Energy- and spectral-efficiency tradeoff with α\alpha-fairness in downlink OFDMA systems

In this letter, we adopt multi-objective optimization to investigate the tradeoff between energy efficiency (EE) and spectral efficiency (SE) in downlink orthogonal frequency division multiple access (OFDMA) systems. In the proposed model, α-fair utility function is applied to take account of the rate fairness among users. We then transfer the original multi-objective optimization into a single objective optimization employing the weighted sum method to obtain the solution set characterized as a Pareto set. The obtained Pareto set demonstrates the tradeoff between EE and SE while α-fairness guarantee is in place. We further consider price of fairness, as a metric to quantify the loss of EE due to enforcing fairness requirements. Such a metric enables the network operators to determine an acceptable operation point in terms of EE-SE tradeoff when certain level of fairness is required. Simulation results indicate that higher fairness results in lower system EE, and the price of fairness is significantly raised with the increase of overall SE

Experimental and theoretical studies of aeroacoustics damping performance of a bias-flow perforated orifice

Aeroacoustics damping performance of an in-duct perforated orifice with a bias flow in terms of acoustic power absorption Δ and reflection χ coefficients are evaluated in this work. For this, experimental measurements of a cold-flow pipe system with a diameter of 2b with an in-duct perforated plate implemented are conducted over the frequency range of 100 to 1000 Hz first. The effects of (1) the downstream pipe length Ld, (2) porosity η, (3) bias flow Mach number Ma and (4) the orifice thickness lw are experimentally evaluated on affecting the noise damping performance of the in-duct perforated orifice. It is found that decreasing Ld leads to increased Δmax (maximum power absorption). However, the orifice thickness plays a negligible effect at lower frequency, and a non-negligible role at higher frequency range. The maximum power absorption Δmax and reflection coefficients χmax are found to be approximately 80% and 90% respectively. There is an optimum porosity or Mach number corresponding to Δmax. In addition, Δ and χ are periodically changed with the forcing frequency. To simulate the experiments and gain insights on the damping performance of the orifice with a diameter of 2a, an 1D theoretical model that embodies vorticity-involved noise absorption mechanism is developed. It is based on the modified form of the Cummings equation describing unsteady flow through an orifice and the Cargill equation describing acoustically open boundary condition at the end of the downstream duct. It is shown that Δ and χ are strongly related to (1) the bias flow Mach number Ma, (2) forcing frequency ω, (3) porosity η, (4) and the downstream pipe length Ld. Comparing with the experimental measurements reveals that good agreement is obtained. This confirms that the present experimental and theoretical study shed lights on the optimum design of in-duct orifices.National Research Foundation (NRF)This work is supported by the University of Canterbury, New Zealand with Grant No. 452STUPDZ, and National Research Foundation, Prime Minister’s Office, Singapore, with Grant No. NRF2016NRF-NSFC001-102 and National Natural Science Foundation of China with Grant No. 11661141020. This financial support is gratefully acknowledged

Cadmium Tolerance and Accumulation of<i> Elsholtzia argyi</i> Origining from a Zinc/Lead Mining Site - A Hydroponics Experiment

<div><p>In this study, a hydroponics experiment was conducted to investigate the characteristics of Cd tolerance and accumulation of <i>Elsholtzia argyi</i> natively growing on the soil with high levels of heavy metals in a Zn/Pb mining site. Seedlings of <i>E. argyi</i> grown for 4 weeks and then were treated with 0(CK), 5, 10, 15, 20, 25, 30, 40, 50, 100 μM Cd for 21days. Each treatment had three replications. No visual toxic symptoms on shoots of <i>E. argyi</i> were observed at Cd level ≤50 μM. The results indicated that the dry biomass of each tissue and the whole plants of the treatments with ≤40 μM cadmium were similar to that of the control, implying that <i>E. argyi</i> was a cadmium tolerant plant. The results also showed that the shoot Cd concentration significantly (P < 0.05) increased with the increase in the Cd level in nutrient solution. The shoot Cd concentration of the treatment with 40 μM Cd was as high as 237.9 mg kg^–1, which was higher than 100 mg kg^–1, normally used as the threshold concentration for identifying the Cd hyperaccumulating plant. It could be concluded that <i>E. argyi</i> was a Cd tolerant and accumulating plant species.</p> </div

Correction to: Cryptotanshinone activates AMPK-TSC2 axis leading to inhibition of mTORC1 signaling in cancer cells

Following publication of the original article [1], the author noticed the following errors in the article