FE analysis on the influence of width direction deformation on springback control in v-bending by sheet forging

There have some problems in the press engineering. One of the most representative phenomena is springback. Traditionally, a series of empirical methods were used to obtain target bending angle. However, such methods are relied on the ability and experience of engineer. Therefore, the control of springback is important. According to the viewpoint of plastic processing, it is considered that springback could be controlled by sheet forging method which was added after V-bending process used a punch with a single lump-punch. On the other hand, warp would occur in air bending process when the ratio of width to thickness is relatively small. So, it is considered that width direction deformation would affect springback control to some extent in case of warp is occurred. In this study, V-bending and continuous forging processes were conducted used FE analysis. From the analytical results, occurrence of warp was found. Next, model of these processes in consideration of warp was re-modified. Finally, it was found that the springback was controlled to some extent derived from width direction deformation

Generalizing to new calorimeter geometries with Geometry-Aware Autoregressive Models (GAAMs) for fast calorimeter simulation

Generation of simulated detector response to collision products is crucial to data analysis in particle physics, but computationally very expensive. One subdetector, the calorimeter, dominates the computational time due to the high granularity of its cells and complexity of the interaction. Generative models can provide more rapid sample production, but currently require significant effort to optimize performance for specific detector geometries, often requiring many networks to describe the varying cell sizes and arrangements, which do not generalize to other geometries. We develop a {\it geometry-aware} autoregressive model, which learns how the calorimeter response varies with geometry, and is capable of generating simulated responses to unseen geometries without additional training. The geometry-aware model outperforms a baseline, unaware model by 50\% in metrics such as the Wasserstein distance between generated and true distributions of key quantities which summarize the simulated response. A single geometry-aware model could replace the hundreds of generative models currently designed for calorimeter simulation by physicists analyzing data collected at the Large Hadron Collider. For the study of future detectors, such a foundational model will be a crucial tool, dramatically reducing the large upfront investment usually needed to develop generative calorimeter models

Revolutionizing digital healthcare networks with wearable strain sensors using sustainable fibers

Wearable strain sensors have attracted research interest owing to their potential within digital healthcare, offering smarter tracking, efficient diagnostics, and lower costs. Unlike rigid sensors, fiber‐based ones compete with their flexibility, durability, adaptability to body structures as well as eco‐friendliness to environment. Here, the sustainable fiber‐based wearable strain sensors for digital health are reviewed, and material, fabrication, and practical healthcare aspects are explored. Typical strain sensors predicated on various sensing modalities, be it resistive, capacitive, piezoelectric, or triboelectric, are explained and analyzed according to their strengths and weaknesses toward fabrication and applications. The applications in digital healthcare spanning from body area sensing networks, intelligent health management, and medical rehabilitation to multifunctional healthcare systems are also evaluated. Moreover, to create a more complete digital health network, wired and wireless methods of data collection and examples of machine learning are elaborated in detail. Finally, the prevailing challenges and prospective insights into the advancement of novel fibers, enhancement of sensing precision and wearability, and the establishment of seamlessly integrated systems are critically summarized and offered. This endeavor not only encapsulates the present landscape but also lays the foundation for future breakthroughs in fiber‐based wearable strain sensor technology within the domain of digital health

Unified Physical-Digital Face Attack Detection

Face Recognition (FR) systems can suffer from physical (i.e., print photo) and digital (i.e., DeepFake) attacks. However, previous related work rarely considers both situations at the same time. This implies the deployment of multiple models and thus more computational burden. The main reasons for this lack of an integrated model are caused by two factors: (1) The lack of a dataset including both physical and digital attacks with ID consistency which means the same ID covers the real face and all attack types; (2) Given the large intra-class variance between these two attacks, it is difficult to learn a compact feature space to detect both attacks simultaneously. To address these issues, we collect a Unified physical-digital Attack dataset, called UniAttackData. The dataset consists of $1,800$ participations of 2 and 12 physical and digital attacks, respectively, resulting in a total of 29,706 videos. Then, we propose a Unified Attack Detection framework based on Vision-Language Models (VLMs), namely UniAttackDetection, which includes three main modules: the Teacher-Student Prompts (TSP) module, focused on acquiring unified and specific knowledge respectively; the Unified Knowledge Mining (UKM) module, designed to capture a comprehensive feature space; and the Sample-Level Prompt Interaction (SLPI) module, aimed at grasping sample-level semantics. These three modules seamlessly form a robust unified attack detection framework. Extensive experiments on UniAttackData and three other datasets demonstrate the superiority of our approach for unified face attack detection.Comment: 12 pages, 8 figure

Performance evaluation of a membrane-based flat-plate heat and mass exchanger used for liquid desiccant regeneration

Liquid desiccant dehumidification system has gained much progress recently for its considerable energy saving potential without liquid water condensation. Within the system, regeneration is of great importance since diluted desiccant solution after dehumidification needs to be re-concentrated. The operational characteristics of a membrane-based flat-plate heat and mass exchanger used for liquid desiccant regeneration are investigated in this study. The liquid desiccant and air are in a cross-flow arrangement, and separated by semi-permeable membranes to avoid carry-over problem. The regeneration performance is examined by numerical simulation and experimental test. Solution side effectiveness, temperature decrease rate (TDR) and moisture flux rate (MFR) are applied to evaluate heat and mass transfer in the regenerator. Effects of main operating parameters are assessed, which include dimensionless parameters (i.e. number of heat transfer units NTU and solution to air mass flow rate ratio m∗), solution inlet properties (i.e. temperature T sol,in and concentration C sol,in) and air inlet conditions (i.e. temperature T air,in and humidity ratio air,in). It is found that m∗ and NTU are two of the most important parameters and their effects on the regeneration performance are interacted with each other. There is hardly benefit to the performance improvement by increasing NTU at low m∗ or increasing m∗ at low NTU. Even though the regeneration performance can be improved by increasing m∗ and NTU, its improvement gradient is limited when m∗ and NTU exceed 2 and 4 respectively. It is also found that increasing olution inlet temperature is an effective approach to enhance the regeneration performance, while air inlet temperature and humidity ratio have negligible effects on it

Optimization of Multi-Functional 1310 nm Spectral-Domain Optical Coherence Tomography (SD-OCT) System and Three-Dimensional Volumetric OCT Image Registration

Optical coherence tomography (OCT) is a novel and promising imaging technique that has been widely applied in clinical practice and research. Currently advanced spectral-domain OCT is capable for fast generating three dimensional (3D) volumetric image and extracting multi-biological information that has potential uses in disease study. Based on a laboratory-built multi-functional spectral-domain OCT system with center wavelength of 1310 nm, the research goal in this thesis is to solve problems about proper optical characterization method of volumes of in vivo biological sample taken at different time points which requires appropriate 3D volume registration and alignment. In this thesis, system optimization is introduced in order to improve OCT signal-to-noise ratio (SNR) and image quality for better image registration performance. Details of a computational-efficient 3D volume alignment based on cross-correlation image registration is discussed. Optical characterization of post-traumatic epilepsy (PTE) is described as an example to demonstrate the feasibility of the OCT system and to evaluate the image post-processing method in actual neural disease research

Zero-Hopf bifurcation and Hopf bifurcation for smooth Chua’s system

Abstract Based on the fact that Chua’s system is a classic model system of electronic circuits, we first present modified Chua’s system with a smooth nonlinearity, described by a cubic polynomial in this paper. Then, we explore the distribution of the equilibrium points of the modified Chua circuit system. By using the averaging theory, we consider zero-Hopf bifurcation of the modified Chua system. Moreover, the existence of periodic solutions in the modified Chua system is derived from the classical Hopf bifurcation theorem

FE analysis on the influence of width direction deformation on springback control in v-bending by sheet forging

There have some problems in the press engineering. One of the most representative phenomena is springback. Traditionally, a series of empirical methods were used to obtain target bending angle. However, such methods are relied on the ability and experience of engineer. Therefore, the control of springback is important. According to the viewpoint of plastic processing, it is considered that springback could be controlled by sheet forging method which was added after V-bending process used a punch with a single lump-punch. On the other hand, warp would occur in air bending process when the ratio of width to thickness is relatively small. So, it is considered that width direction deformation would affect springback control to some extent in case of warp is occurred. In this study, V-bending and continuous forging processes were conducted used FE analysis. From the analytical results, occurrence of warp was found. Next, model of these processes in consideration of warp was re-modified. Finally, it was found that the springback was controlled to some extent derived from width direction deformation