Dense Text-to-Image Generation with Attention Modulation

Existing text-to-image diffusion models struggle to synthesize realistic images given dense captions, where each text prompt provides a detailed description for a specific image region. To address this, we propose DenseDiffusion, a training-free method that adapts a pre-trained text-to-image model to handle such dense captions while offering control over the scene layout. We first analyze the relationship between generated images' layouts and the pre-trained model's intermediate attention maps. Next, we develop an attention modulation method that guides objects to appear in specific regions according to layout guidance. Without requiring additional fine-tuning or datasets, we improve image generation performance given dense captions regarding both automatic and human evaluation scores. In addition, we achieve similar-quality visual results with models specifically trained with layout conditions.Comment: Accepted by ICCV2023. Code and data are available at https://github.com/naver-ai/DenseDiffusio

Approach to Higher Wheat Yield in the Huang-Huai Plain: Improving Post-anthesis Productivity to Increase Harvest Index

Both increased harvest index (HI) and increased dry matter (DM) are beneficial to yield; however, little is known about the priority of each under different yield levels. This paper aims to determine whether HI or DM is more important and identify the physiological attributes that act as indicators of increased yield. Two field experiments involving different cultivation patterns and water-nitrogen modes, respectively, were carried out from 2013 to 2016 in Huang-Huai Plain, China. Plant DM, leaf area index (LAI), and radiation interception (RI) were measured. Increased yield under low yield levels <7500 kg ha-1 was attributed to an increase in both total DM and HI, while increases under higher yield levels >7500 kg ha-1 were largely dependent on an increase in HI. Under high yield levels, HI showed a significant negative correlation with total DM and a parabolic relationship with net accumulation of DM during filling. Higher net accumulation of DM during filling helped slow down the decrease in HI, thereby maintaining a high value. Moreover, net DM accumulation during filling was positively correlated with yield, while post-anthesis accumulation showed a significant linear relationship with leaf area potential (LAP, R2 = 0.404–0.526) and radiation interception potential (RIP, R2 = 0.452–0.576) during grain filling. These findings suggest that the increase in LAP and RIP caused an increase in net DM accumulation after anthesis. Under DM levels >13,000 kg ha-1 at anthesis, maintaining higher LAI and RI in lower layers during grain formation contributed to higher yield. Furthermore, the ratio of upper- to lower-layer RI showed a second-order curve with yield during filling, with an increase in the optimal range with grain development. Pre-anthesis translocation amount, translocation ratios and contribution ratios also showed second-order curves under high yield levels, with optimal values of 3000–4500 kg ha-1, 25–35, and 30–50%, respectively. These results confirm the importance of HI in improving the yield, thereby providing a theoretical basis for wheat production in the Huang-Huai Plain

Flame spread and smoke temperature of full-scale fire test of car fire

Full-scale experiments using two 4-door sedan passenger cars, placed side by side in the reverse direction, were carried out to establish the burning behavior and describe the spread of fire to adjacent car. The temperature was measured by thermocouples. Radiant heat flux was measured with heat flux gauge placed at a distance of 5 m, at the right side of the car. Four cameras were placed inside the car and in the fire test room recording burning behavior during the test. Engine compartment was ignited by a sponge dipped with little gasoline. During the experiment, the ignition was initiated in the engine compartment of car I and approximately 20 min were enough time for fire to spread into the second car. Fully-developed burning of two cars occurred at 29 min. It was observed that the flame spread through car roof faster than through the bottom of car compartment. The fire followed a slow rate spread from engine compartment to car cab. The temperature inside the car peaked at the point of 900 °C. The peak smoke temperatures at every location were measured at the range of 89–285 °C. The smoke production at the time of 11 min to 15 min 50 s of fire was 1.76 m3/s, which was obtained through indirect calculation method

Numerical study on the effects of opening form on the deflation for an air-supported membrane structure

Air-supported membrane structure has been widely applied to large-span space due to its advantages of light weight, low cost, reusability. The static load bearing capacity and the dynamic deployment simulation of air-supported membrane structure have received extensive attention. However, very few studies have been reported to investigate its deflation behavior. Although several dynamic finite element algorithms can be applied to the deflation simulation, their computational costs are large. The concept of critical pressure point was introduced in this paper, by which the deflation process was divided into two stages of decompression and collapse. A series of numerical simulations were performed to study the effects of opening area and position on the pressure change in decompression process for air-supported membrane structure. The study showed that the required time for the critical pressure point reached initially decreases sharply gradually evolving into a slight decrease as the opening area increases from 0.5 to 6 m2, which followed a power equation as a function of opening area. Moreover, for a fixed opening area, opening position at top exhibits a minimum value followed by middle position, while a maximum value is shown when the opening is at bottom position. It is obviously that the decompression phase is affected significantly by the opening area and position. The above results have a certain meaning for safety assessment of personal evacuation under emergency deflation of the air-supported membrane structure. Keywords: Air-supported membrane structure, Deflation, Opening form, Numerical simulation, Critical pressure poin

Experimental and numerical studies on ceiling maximum smoke temperature and longitudinal decay in a horseshoe shaped tunnel fire

The present paper investigates the ceiling maximum smoke temperature and longitudinal decay in tunnel fires using a horseshoe shaped 1:3.7 scale-model tunnel constructed by concrete and a full-scale model tunnel established by SIMTEC for the first time. The maximum smoke temperature beneath the ceiling and the longitudinal temperature profiles were obtained and analyzed. The major conclusions are summarized as follows: The ceiling maximum smoke temperature rise right above the fire source is directly proportional to the terms of Q2/3/Hf5/3 and the ceiling maximum smoke temperature decreases as a sum function of two exponential equations of horizontal distance. Modified equations are proposed for maximum smoke temperature rise beneath the ceiling and longitudinal temperature decay, and the predictions show a good agreement with the values measured by experiments and numerical simulations. The results obtained by numerical simulations agree well with experimental results, and SIMTEC is reasonable to simulate the tunnel fires to predict the temperature profiles. The results are of important significance for tunnel fire safety and personnel evacuation. Keywords: Ceiling maximum temperature, Longitudinal temperature decay, Horseshoe shaped tunnel, Tunnel fire

Wheat Grain Yield Increase in Response to Pre-Anthesis Foliar Application of 6-Benzylaminopurine Is Dependent on Floret Development

<div><p>Wheat yield is largely determined during the period prior to flowering, when the final numbers of fertile florets and grains per spike are established. The aim of this study was to assess the dynamics of floret primordia development in winter wheat in response to pre-anthesis application of a synthetic cytokinin, 6-benzylaminopurine (6-BA). We conducted an experiment in which two foliar spray treatments were applied (water or 6-BA) to Chinese winter wheat at 25 days after jointing during two growing seasons (2012–2013 and 2013–2014). Both the final grain number per spike and grain yield at maturity exhibited remarkable increases in response to the 6-BA treatment. Application of 6-BA increased the number of fertile florets in basal spikelets and, to a greater extent, in central spikelets. The mechanism by which 6-BA application affected the final number of fertile florets primarily involved suppression of the floret abortion rates. Application of 6-BA considerably reduced the abortion rates of basal, central and apical spikelet florets (by as much as 77% compared with the control), as well as the degeneration rates of basal and central spikelet florets, albeit to a lesser degree. The effect of 6-BA application on the likelihood of proximal florets being set was limited to the distal florets in the whole spike, whereas obvious increases in the likelihood of grain set under 6-BA treatment were observed in distal florets, primarily in central spikelet positions. The results of this study provide important evidence that 6-BA application to florets (final fertile floret production) results in an increased grain yield.</p></div

Number of grains at each spikelet position after the two foliar spray treatments (S0: water [pale grey bars]; S1: 6-BA [dark grey bars]).

<p>The data are presented as the treatment mean ± standard error, n = 3. The different letters indicate significant differences (P < 0.05) at each spikelet position.</p