DualApp: Tight Over-Approximation for Neural Network Robustness Verification via Under-Approximation

The robustness of neural networks is fundamental to the hosting system's reliability and security. Formal verification has been proven to be effective in providing provable robustness guarantees. To improve the verification scalability, over-approximating the non-linear activation functions in neural networks by linear constraints is widely adopted, which transforms the verification problem into an efficiently solvable linear programming problem. As over-approximations inevitably introduce overestimation, many efforts have been dedicated to defining the tightest possible approximations. Recent studies have however showed that the existing so-called tightest approximations are superior to each other. In this paper we identify and report an crucial factor in defining tight approximations, namely the approximation domains of activation functions. We observe that existing approaches only rely on overestimated domains, while the corresponding tight approximation may not necessarily be tight on its actual domain. We propose a novel under-approximation-guided approach, called dual-approximation, to define tight over-approximations and two complementary under-approximation algorithms based on sampling and gradient descent. The overestimated domain guarantees the soundness while the underestimated one guides the tightness. We implement our approach into a tool called DualApp and extensively evaluate it on a comprehensive benchmark of 84 collected and trained neural networks with different architectures. The experimental results show that DualApp outperforms the state-of-the-art approximation-based approaches, with up to 71.22% improvement to the verification result.Comment: 13 pages, 9 fugures, 3 table

Effects of Siraitia grosvenorii seed flour on the properties and quality of steamed bread

Siraitia grosvenorii seeds are rich in abundant active compounds beneficial to human health. To clarify the digestion characteristics of Siraitia grosvenorii seed flour (SSF) and promote the use of SSF in the processing of functional staple foods, SSF was prepared, its composition and physicochemical properties were studied, and the processing characteristics of SSF-wheat flour were systematically investigated. The results showed that the torque curve and other parameters of the dough were significantly affected by the amount of SSF added. With the increase of SSF proportion, the water absorption showed an increasing trend, while the degree of protein weakening first weakened and then enhanced. At 20% SSF, the dough was more resistant to kneading. In response to an increase in SSF, the L* value decreased significantly, and the a* and b* values increased gradually, while the specific volume decreased gradually. Additionally, the hardness, adhesiveness, and chewiness of the bread enhanced gradually, while its elasticity, cohesiveness, and resilience decreased gradually. After the addition of 30% SSF, the inner tissue of steamed bread was more delicate. With an increase in SSF proportion, the predicted glycemic index (pGI) of steamed bread weakened markedly. Overall, these results showed that SSF, as a kind of food ingredient with hypoglycemic activity, can be used in the production of new functional steamed bread products. This study provides basic research data for the development of products containing S. grosvenorii seed

Neuroimaging anomalies in asymptomatic middle cerebral artery steno-occlusive disease with normal-appearing white matter

BackgroundAsymptomatic chronic cerebrovascular steno-occlusive disease is common, but the cognitive function and alterations in the brain’s structural and functional profiles have not been well studied. This study aimed to reveal whether and how patients with asymptomatic middle cerebral artery (MCA) steno-occlusive disease and normal-appearing white matter differ in brain structural and functional profiles from normal controls and their correlations with cognitive function.MethodsIn all, 26 patients with asymptomatic MCA steno-occlusive disease and 22 healthy controls were compared for neurobehavioral assessments, brain volume, cortical thickness, fiber connectivity density (FiCD) value, and resting-state functional connectivity (FC) using multimodal MRI. We also investigated the associations between abnormal cortical thicknesses, FiCD values, and functional connectivities with the neurobehavioral assessments.ResultsPatients performed worse on memory tasks (Auditory Verbal Learning Test-Huashan version) compared with healthy controls. Patients were divided into two groups: the right group (patients with right MCA steno-occlusive disease) and the left group (patients with left MCA steno-occlusive disease). The left group showed significant cortical thinning in the left superior parietal lobule, while the right group showed significant cortical thinning in the right superior parietal lobule and caudal portion of the right middle frontal gyrus. Increased FiCD values in the superior frontal region of the left hemisphere were observed in the left group. In addition, a set of interhemispheric and intrahemispheric FC showed a significant decrease or increase in both the left and right groups. Many functional connectivity profiles were positively correlated with cognitive scores. No correlation was found between cortical thickness, FiCD values, and cognitive scores.ConclusionEven if the patients with MCA steno-occlusive disease were asymptomatic and had normal-appearing white matter, their cognitive function and structural and functional profiles had changed, especially the FC. Alterations in FC may be an important mechanism underlying the neurodegenerative process in patients with asymptomatic MCA steno-occlusive disease before structural changes occur, so FC assessment may promote the detection of network alterations, which may be used as a biomarker of disease progression and therapeutic efficacy evaluation in these patients

Electromagnetic properties of aluminum-based bilayers for kinetic inductance detectors

The complex conductivity of a superconducting thin film is related to the quasiparticle density, which depends on the physical temperature and can also be modified by external pair breaking with photons and phonons. This relationship forms the underlying operating principle of Kinetic Inductance Detectors (KIDs), where the detection threshold is governed by the superconducting energy gap. We investigate the electromagnetic properties of thin-film aluminum that is proximitized with either a normal metal layer of copper or a superconducting layer with a lower TC , such as iridium, in order to extend the operating range of KIDs. Using the Usadel equations along with the Nam expressions for complex conductivity, we calculate the density of states and the complex conductivity of the resulting bilayers to understand the dependence of the pair breaking threshold, surface impedance, and intrinsic quality factor of superconducting bilayers on the relative film thicknesses. The calculations and analyses provide theoretical insights in designing aluminum-based bilayer kinetic inductance detectors for detection of microwave photons and athermal phonons at the frequencies well below the pair breaking threshold of a pure aluminum film

Dynamics of Territorial Spatial Pattern and Landscape Impact under Different Economic Gradients: A Case Study of the Beijing-Tianjin-Hebei (BTH) Region, China

This study analyzes territorial spatial pattern changes and landscape pattern changes under different economic development gradients in 1980, 1990, 2000, 2010 and 2018 in the Beijing-Tianjin-Hebei (BTH) region of China. Then it discusses the relationship between territorial area and landscape patterns. The results indicate that: (1) area changes for middle- and low-development regions are characterized by “continuous shrinkage of agricultural space, continuous expansion of urban space, and a decrease followed by an increase of ecological space”; (2) the higher the level of regional economic development, the more severe the spatial change of national territory; (3) the common trend of structural transformation is the obvious flow of agricultural production space into rural living space and urban space—the difference is that the outflow of ecological space in low-development regions is more than the inflow, while the opposite holds true in medium- and high-development regions; and (4) the fragmentation degree of middle- and low-development regions is increasing, while that of high-development regions is decreasing. With the increase in regional economic development, the degree of spread and diversity decreases and increases, respectively. The correlation between territorial spatial pattern and landscape metrics shows distinct regional differences

Revisiting Hua-Marcus-Bellman-Ando Inequalities on Contractive Matrices

Loo-Keng Hua showed some elegant matrix and determinant inequalities via a matrix identity and proved the positive semidefiniteness of a matrix involving the determinants of contractive matrices through group representation theory. His study was followed by M. Marcus, R. Bellman and T. Ando. The purpose of current paper is to revisit the Hua’s original work and the results of Marcus, Bellman and Ando with our comments, and to present analogs and extensions to their result

Analyzing Stakeholder Relationships for Construction Land Reduction Projects in Shanghai, China

With the tightening of resource and environmental constraints and the increasing manifestation of land use conflicts, construction land reduction has become an important way to optimize land resource allocation and improve resource use efficiency. Taking the towns of Zhuqiao and Zhujiajiao in Shanghai as research subjects, this paper uses field research and case studies to summarize the main practices and completion of the land reduction and analyzes the interest preferences of different stakeholders. The results showed that the main stakeholders in the reduction of inefficient construction land in Shanghai include the municipal government, district government, town government, rural collective economic organizations, entrepreneurs, and villagers, which form a complex and intertwined interest relationship. The allocation of new construction land indexes, the supply of funds for the cost of reduction, and the resettlement method of the reduced enterprises are the key factors affecting the coordination of the relationship between the stakeholders. Protecting the economic interests of village collective organizations and villagers is an effective way to reduce the conflicts that occur between government and villagers, and between government and village collectives. The research outcomes will provide a theoretical reference for improving the existing reduction policies and function as a reference for the spatial development and control work in other regions of China