LLM-Enhanced Data Management

Machine learning (ML) techniques for optimizing data management problems have been extensively studied and widely deployed in recent five years. However traditional ML methods have limitations on generalizability (adapting to different scenarios) and inference ability (understanding the context). Fortunately, large language models (LLMs) have shown high generalizability and human-competitive abilities in understanding context, which are promising for data management tasks (e.g., database diagnosis, database tuning). However, existing LLMs have several limitations: hallucination, high cost, and low accuracy for complicated tasks. To address these challenges, we design LLMDB, an LLM-enhanced data management paradigm which has generalizability and high inference ability while avoiding hallucination, reducing LLM cost, and achieving high accuracy. LLMDB embeds domain-specific knowledge to avoid hallucination by LLM fine-tuning and prompt engineering. LLMDB reduces the high cost of LLMs by vector databases which provide semantic search and caching abilities. LLMDB improves the task accuracy by LLM agent which provides multiple-round inference and pipeline executions. We showcase three real-world scenarios that LLMDB can well support, including query rewrite, database diagnosis and data analytics. We also summarize the open research challenges of LLMDB

Interferon-alpha responsible EPN3 regulates hepatitis B virus replication

Hepatitis B virus (HBV) infection remains a major health problem worldwide, and the current antiviral therapy, including nucleoside analogs, cannot achieve life-long cure, and clarification of antiviral host immunity is necessary for eradication. Here, we found that a clathrin-binding membrane protein epsin3 (EPN3) negatively regulates the expression of HBV RNA. EPN3 expression was induced by transfection of an HBV replicon plasmid, and reduced HBV-RNA level in hepatic cell lines and murine livers hydrodynamically injected with the HBV replicon plasmid. Viral RNA reduction by EPN3 was dependent on transcription, and independent from epsilon structure of viral RNA. Viral RNA reduction by overexpression of p53 or IFN-α treatment, was attenuated by knockdown of EPN3, suggesting its role downstream of IFN-α and p53. Taken together, this study demonstrates the anti-HBV role of EPN3. The mechanism how it decreases HBV transcription is discussed

Investigation of Thermo-chemo-mechanically Coupled Phenomena in Frontal Polymerization

Frontal polymerization is a proven energy-saving and rapid method of synthesizing polymers with good mechanical properties. With a small energy input, a reaction front propagates rapidly through the sample, transforming monomer (liquid or soft gel) into polymer (stiff solid), and is self-sustained by heat released from the polymerization reaction itself. A thermo-chemical coupled model has been proposed to describe the frontal polymerization process, and recent experiments have shown that such coupling could lead to an unstable propagating front. However, the influence of mechanical forces has been absent in previous analyses of frontal polymerization, which could be significant considering local volume change caused by thermal expansion and chemical shrinkage as the front propagates. In this thesis, we will explore the mechanical behavior and potential thermal-chemo-mechanically coupled effects that may emerge during frontal polymerization of soft gels. We will show that non-uniform residual stress distribution could be generated due to differences in thermal and chemical properties on both sides of the propagating front. Our experiments further confirm that the emergence of stress could in turn influence the propagation of front, and our model describes such coupling effects to predict the dynamics of a propagating front in agreement with experimental observation. Our findings suggest that the mechanical effects need to be taken into consideration for industrial applications of frontal polymerization at large scales.S.M

An improved wall shear stress measurement technique using sandwiched hot-film sensors

ABSTRACT: In this letter we present a novel wall shear stress measurement technique for a turbulent boundary layer using sandwiched hot-film sensors. Under certain conditions, satisfactory results can be obtained using only the heat generated by one of the hot-film and a calibration of the sensors is not required. Two thin Nickel films with the same size were used in this study, separated by an electrical insulating layer. The upper film served as a sensor and the bottom one served as a guard heater. The two Nickel films were operated at a same temperature, so that the Joule heat flux generated by the sensor film transferred to the air with a minimum loss or gain depending on the uncertainties in the film temperature measurements. Analytical solution of the shear stress based on the aforementioned heat flux was obtained. The preliminary results were promising and the estimated wall shear stresses agreed reasonably well with the directly measured values (with errors less than 20%) in a fully developed turbulent pipe flow. The proposed technique can be improved to further increase precisions. Keywords: Wall shear stress, Skin friction, Hot-film, MEMS, Calibration-fre

A novel approach to hazard evaluation for MASS operation based on a hesitant fuzzy linguistic term set

Expert judgment has been widely utilized in ship risk assessment. The traditional method is believed to be capable of processing only designated linguistic variables, which fails to capture the degree of expert hesitation in assessing a complex system. A novel model, the bi-independent hesitant fuzzy linguistic term set (BHFLTS), based on the hesitant fuzzy linguistic term set (HFLTS), is proposed to incorporate this hesitation. This paper also identifies ten navigational hazards to maritime autonomous surface ship (MASS) operation based on a literature review. In addition, the BHFLTS approach combined with the technique for order preference by similarity to an ideal solution (TOPSIS) is utilized for hazard assessment and ranking, and with this method, “Collision avoidance decision algorithm malfunction”, “Ship situation awareness system failure” and “Command transmission system failure” are rated as the top three navigational hazards that threaten MASS operation

Influence of surface effect on mechanical properties of thermo-mechanical porous cantilever nanobeams

The surface effect has an important influence on the mechanical properties of nanostructures. Many micro and nano-scale structures on aircraft can be simplified as cantilever beams. In this paper，the influence of surface effect on the nonlinear mechanical response of gradient porous material nano cantilever under follower load at high temperature was analyzed. Based on Gurtin-Murdoch's surface elastic theory and nonlinear beam theory，the nonlinear governing differential equations of gradient porous material beam under follower load and temperature field were established. It was assumed that the properties of gradient porous materials change continuously in the entire thickness range，and there were two kinds of non-uniform porosity distribution patterns in cosine form along the thickness. The nonlinear mechanical response of the gradient porous material cantilever nanobeam under thermal follower load was solved by shooting method. The numerical solutions of the nonlinear mechanical response of the cantilever under various porosity coefficients and different non-uniform temperature rises were obtained. The effects of the material surface elastic constants and surface stresses on the mechanical response of the cantilever were discussed in detail. The results show that the mechanical behaviors of beams are different under different porosity coefficients and different non-uniform temperature rises. The nanobeams exhibit very significant surface effects

Plasma Surface Treatment and Application of Polyvinyl Alcohol/Polylactic Acid Electrospun Fibrous Hemostatic Membrane

In this study, an improved PVA/PLA fibrous hemostatic membrane was prepared by electrospinning technology combined with air plasma modification. The plasma treatment was used to modify PLA to enhance the interlayer bonding between the PVA and PLA fibrous membranes first, then modify the PVA to improve the hemostatic capacity. The surfaces of the PLA and PVA were oxidized after air plasma treatment, the fibrous diameter was reduced, and roughness was increased. Plasma treatment enhanced the interfacial bond strength of PLA/PVA composite fibrous membrane, and PLA acted as a good mechanical support. Plasma-treated PVA/PLA composite membranes showed an increasing liquid-enrichment capacity of 350% and shortened the coagulation time to 258 s. The hemostatic model of the liver showed that the hemostatic ability of plasma-treated PVA/PLA composite membranes was enhanced by 79% compared to untreated PVA membranes, with a slight improvement over commercially available collagen. The results showed that the plasma-treated PVA/PLA fibers were able to achieve more effective hemostasis, which provides a new strategy for improving the hemostatic performance of hemostatic materials