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In this study, two types of Si3N4 ball bearings for integrated-type EV reducers developed via different manufacturing processes were analyzed to study the microstructure of the balls and the defects that may occur during the manufacturing process. Three types of defects were confirmed that can reduce the fatigue life of Si3N4 ball bearings in operating environments. The microstructure was analyzed to identify the main additive components of each bearing, and pore defects with a size of less than 1 μm, and the types (particle defects or surface defects) and sizes of defects, were analyzed using LSCM, OM, and SEM. Hardness and fracture toughness, which are representative mechanical properties of ceramic materials, were evaluated. The results, evaluated using a Vickers indentation crack-based method, were statistically analyzed to confirm differences in hardness and fracture toughness between the two samples. [ABSTRACT FROM AUTHOR]

In this study, we explore the implications of advancing AI technology on the safety of machine learning models, specifically in decision-making across diverse applications. Our research delves into the domain of network intrusion detection, covering rule-based and anomaly-based detection methods. There is a growing interest in anomaly detection within network intrusion detection systems, accompanied by an increase in adversarial attacks using maliciously crafted examples. However, the vulnerability of intrusion detection systems to backdoor attacks, a form of adversarial attack, is frequently overlooked in untrustworthy environments. This paper proposes a backdoor attack scenario, centering on the "AlertNet" intrusion detection model and utilizing the NSL-KDD dataset, a benchmark widely employed in NIDS research. The attack involves modifying features at the packet level, as network datasets are typically constructed from packets using statistical methods. Evaluation metrics include accuracy, attack success rate, baseline comparisons with clean and random data, and comparisons involving the proposed backdoor. Additionally, the study employs KL-divergence and OneClassSVM for distribution comparisons to demonstrate resilience against manual inspection by a human expert from outliers. In conclusion, the paper outlines applications and limitations and emphasizes the direction and importance of research on backdoor attacks in network intrusion detection systems. [ABSTRACT FROM AUTHOR]

Increasing the number of satellites in a global navigation satellite system (GNSS) improves the positioning accuracy and increases availability. However, it reduces the positioning accuracy improvement rate and increases the calculation loads, which can cause battery usage problems in mobile devices using a GNSS. An appropriate satellite selection method is required. One current method entails the use of ideal satellite placement with respect to the minimum geometric dilution of precision (GDOP). In this study, the described ideal satellite placement with the minimum GDOP were divided in terms of the horizontal dilution of precision (HDOP) and vertical dilution of precision (VDOP). HDOP and VDOP were mathematically derived and analyzed. The derived formula was verified using simulations. The analysis was performed with actual dual GNSS satellite data. The satellites adjacent to the ideal placement were selected and the DOP was calculated. Simply selecting satellites closest to the ideal placement afforded large values for HDOP and VDOP. This issue was addressed using a satellite changing algorithm considering the dual GNSS, resulting in reduced values of the HDOP and VDOP. [ABSTRACT FROM AUTHOR]

Heat generated by viscous energy dissipation and friction during high‐frequency fatigue testing can reduce the fatigue life of short fiber‐reinforced plastics. Herein, we proposed new method of determining an appropriate testing frequency, taking into consideration the temperature increase in SFRPs during fatigue testing. An experimental procedure was developed to obtain viscoelastic and thermal parameters in a theoretical model using dynamic mechanical analyses and fatigue tests with an infrared camera. Then, according to the stress levels under tension in fatigue tests, a critical frequency was calculated to allow a temperature increase within 10°C. Finally, experimental fatigue tests at low stress levels and high frequencies were performed, demonstrating the applicability of the current method to design fatigue tests that take into account stress levels at a given frequency and a limited temperature rise. [ABSTRACT FROM AUTHOR]

Steel-polymer sandwich composites are relatively strong and lightweight materials. However, accurately predicting the mechanical properties of these materials has been challenging, presumably due to a lack of consideration of their interfacial properties. In this study, the interfacial adhesion in sandwich composites was systematically varied to evaluate its effects on mechanical properties, particularly tensile strength. Next, we investigated why the tensile capacity (strength) of each component is not fully realized for seemingly simple structures consisting of two steel layers and a core polymer layer when assuming relatively weak adhesion. The resulting interfacial properties of the sandwich composites were characterized and incorporated into a cohesive zone model for finite element simulation. The simulation results revealed that, in contrast to the strong adhesion case, weak adhesion leads to stress concentration around failed cohesive elements, resulting in earlier failure of constituent layers and thus a lowering of the overall tensile strength of the composite. [ABSTRACT FROM AUTHOR]

The fracture strain of carbon fiber-reinforced plastics (CFRPs) within CFRP/steel hybrid laminate composites is reportedly higher than that of CFRPs due to transverse compressive stress induced by the steel lamina. A micromechanical model was developed to explain this phenomenon and also to predict the mechanical behavior of CFRP/steel hybrid laminate composites. First, the shear lag theory was extended to calculate stress distributions on fibers and matrix material in a CFRP under multiaxial stress condition, considering three deformation states of matrix (elastic and plastic deformation and fracture) and the transverse compressive stress. Then, the deformation behavior of CFRP was predicted using average stress in the ineffective region and the Weibull distribution of carbon fibers. Finally, the mechanical properties of CFRP/steel hybrid laminate composites were predicted by considering the thermal residual stress generated during the manufacturing process. The micromechanical model revealed that increased transverse compressive stress decreases the ineffective lengths of partially broken fibers in the CFRP and results in increased fracture strain of the CFRP, demonstrating the validity of the current micromechanical model. [ABSTRACT FROM AUTHOR]

Design of materials with remote switchability of the movement of decorated nanostructures presenting cell‐adhesive Arg‐Gly‐Asp ligand can decipher dynamic cell‐material interactions in decorated ligand nanostructures. In this study, the decoration of ligand‐bearing gold nanoparticles (ligand‐AuNPs) on the magnetic nanoparticle (MNP) with varying ligand‐AuNP densities is demonstrated, which are flexibly coupled to substrate in various MNP densities to maintain constant macroscopic ligand density. Magnetic switching of upward ("Upper Mag") or downward ("Lower Mag") movement of varying ligand‐AuNPs is shown via stretching and compression of the elastic linker, respectively. High ligand‐AuNP densities promote macrophage adhesion‐regulated M2 polarization that inhibits M1 polarization. Remote switching of downward movement ("Lower Mag") of ligand‐AuNPs facilitates macrophage adhesion‐regulated M2 polarization, which is conversely suppressed by their upward movement ("Upper Mag"), both in vitro and in vivo. These findings are consistent with human primary macrophages. These results provide fundamental understanding into designing materials with decorated nanostructures in both high ligand‐AuNP density and downward movement of the ligand‐AuNPs toward the substrate to stimulate adhesion‐regulated M2 polarization of macrophages while suppressing pro‐inflammatory M1 polarization, thereby facilitating tissue‐healing responses. [ABSTRACT FROM AUTHOR]

Facial expression recognition (FER) is increasingly gaining importance in various emerging affective computing applications. In practice, achieving accurate FER is challenging due to the large amount of inter-personal variations such as expression intensity variations. In this paper, we propose a new spatio-temporal feature representation learning for FER that is robust to expression intensity variations. The proposed method utilizes representative expression-states (e.g., onset, apex and offset of expressions) which can be specified in facial sequences regardless of the expression intensity. The characteristics of facial expressions are encoded in two parts in this paper. As the first part, spatial image characteristics of the representative expression-state frames are learned via a convolutional neural network. Five objective terms are proposed to improve the expression class separability of the spatial feature representation. In the second part, temporal characteristics of the spatial feature representation in the first part are learned with a long short-term memory of the facial expression. Comprehensive experiments have been conducted on a deliberate expression dataset (MMI) and a spontaneous micro-expression dataset (CASME II). Experimental results showed that the proposed method achieved higher recognition rates in both datasets compared to the state-of-the-art methods. [ABSTRACT FROM AUTHOR]

We advance the literature on electoral institutions and legislative representation by investigating legislators' position taking strategies in Taiwan under the single non-transferable voting period. Existing research largely assumes that representatives elected from the same electoral rule behave similarly. We challenge this conventional understanding by arguing that legislators in multi-member districts (MMDs) tend to move toward the extreme direction from the party line if they come from districts where their party is less competitive. This pattern of legislative representation allows them to appeal to partisan voters, as lowering one's partisan profile can be too costly in such districts. On the contrary, those who are elected from strong partisan districts are expected to deviate from the party toward the moderate direction. Given a solid partisan foundation in these districts, these legislators may target voters across party lines. Our analysis covering the entire period of MMD elections after Taiwan's democratization (1992–2008) provides robust empirical evidence to our theoretical claim. Our findings, therefore, shed lights for future studies on the intertwining nature between electoral systems, district level factors, and legislative representation. [ABSTRACT FROM AUTHOR]

This paper presents a recurrent learning-based facial attribute recognition method that mimics human observers’ visual fixation. The concentrated views of a human observer while focusing and exploring parts of a facial image over time are generated and fed into a recurrent network. The network makes a decision concerning facial attributes based on the features gleaned from the observer’s visual fixations. Experiments on facial expression, gender, and age datasets show that applying visual fixation to recurrent networks improves recognition rates significantly. The proposed method not only outperforms state-of-the-art recognition methods based on static facial features, but also those based on dynamic facial features. [ABSTRACT FROM AUTHOR]

Macrophage Polarization: Remote Switching of Elastic Movement of Decorated Ligand Nanostructures Controls the Adhesion-Regulated Polarization of Host Macrophages (Adv. Funct. Keywords: elastic ligand movement; macrophage adhesion; macrophage polarization; magnetic switching; nanoparticle decoration EN elastic ligand movement macrophage adhesion macrophage polarization magnetic switching nanoparticle decoration 1 1 1 05/26/21 20210521 NES 210521 In article number 2008698, Young Keun Kim, Heemin Kang, and co-workers report magnetic switching of the movement of decorated ligand-presenting nanostructures that regulates the adhesion-mediated polarization of macrophages in vivo. Elastic ligand movement, macrophage adhesion, macrophage polarization, magnetic switching, nanoparticle decoration. [Extracted from the article]