Kanagawa University

This work explores the impact of optimal power allocation on the physical layer security of lossy decode-and-forward untrusted relay networks using Alamouti Space-Time Block Code (STEG). We introduce the reliable-and-secure probability (RS?) metric to measure the likelihood of successful message recovery at the destination while ensuring the message remains unintelligible to the relays. In high spectral efficiency scenarios, allocating more power to the untrusted relay significantly enhances the RS?, surpassing low spectral efficiency results. A balanced power allocation between the source and the relay, with Alamouti STBC, achieves a high RS?. However, the peak RS? is achieved when the power contributions from the source and the relay are balanced.

In order to realize the buckling-restrained brace (BRB) with high energy dissipation performance, it is important to prevent early local bulging failure of the restraining part. In this study, local bulging failure in the strong axial direction of the core plate of the BRB with steel mortar planks is examined. Based on the experimental results and the discussion of previous studies, the strength of the restraining part against local bulging failure considering the effect of spacers was calculated and verified.

This study will ascertain the actual conditions of creative activities by citizens that have been undertaken in public art museums. The purpose is to gain knowledge for planning art museums as public facilities that generate a new sense of participation. In order to capture the actual status of creative activities, a questionnaire survey was conducted in public art museums. Field surveys were conducted to capture the actual conditions of art museums use by creative activities. Based on the findings from the survey analysis, the report summarizes the state of art museums from the perspective of creative activities.

In this study, an aerial tour guide drone was developed based on the existing Coanda‐drone. The research integrated a Voice Information Presentation System with ROS2 using the open‐source PX4 flight control system to update the drone's control module. This system can recognize and read QR codes on displayed items and convert the text information from QR codes into speech for playback. It also utilizes left and right laser sensors for obstacle avoidance. Furthermore, the study conducted both simulation experiments and actual flight tests to validate the feasibility of equipping the Coanda‐drone with the voice information presentation system and to assess the flight capabilities of the Coanda‐drone. This system offers a novel solution for guidance and obstacle avoidance, demonstrating the potential of drones as flexible, highly secure, and efficient mobile service robots in the future. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.

Given a metrizable space X X , let A M ( X ) AM\left(X) be the space of continuous bounded admissible metrics on X X , which is endowed with the sup-metric. In this article, we shall investigate the Borel complexity and the complete metrizability of A M ( X ) AM\left(X) and show that a separable metrizable space X X is σ \sigma -compact if and only if A M ( X ) AM\left(X) is completely metrizable.

Adult tissue stem cells of the anterior pituitary gland, CD9/SOX2-positive cells, are believed to exist in the marginal cell layer (MCL) bordering the residual lumen of the Rathke’s pouch. These cells migrate from the intermediate lobe side of the MCL (IL-MCL) to the anterior lobe side of the MCL and may be involved in supplying hormone-producing cells. Previous studies reported that some SOX2-positive cells of the anterior lobe differentiate into skeletal muscle cells. These findings suggest that CD9/SOX2-positive cells in the anterior pituitary have mesenchymal stem cell (MSC) properties. To substantiate this hypothesis, we examined whether CD9-positive cells isolated from IL-MCL of adult male rats differentiate into mesenchymal cells, such as endothelial cells, adipocytes, chondrocytes, and osteocytes. Immunohistochemical analysis revealed that the CD9-positive cells were positive for the MSC markers, CD349, CD105, CD271, and CD273 and were detected in the early postnatal period at the boundary between the posterior and intermediate lobes but not in the embryonic period. In addition, some adult tissue stem cells derived from external tissues were positive for both CD9 and MSC markers, indicating that few CD9/SOX2-positive cells in the IL-MCL of the pituitary gland are MSCs that invaded from external tissues during pituitary development in the early postnatal period and exist in the adult tissue stem cells as suppliers of hormone-producing and endothelial cells in the anterior lobe. These finding should have implications for application of CD9/SOX2-positive cells in regenerative therapy of the pituitary.

IMP-type metallo-β-lactamases are di-Zn(II) enzymes that can inactivate a wide range of bicyclic β-lactam agents used in clinical practice. IMP-27 shares 82% amino acid sequence identity with IMP-1, the first IMP-type enzyme identified. Herein, we conducted structural determination, kinetic, and chelating agent resistance analyses of IMP-27. Once determined, IMP-27 was then compared to its mutant, namely, G262S, and IMP-1. Crystallographic structural analysis of IMP-27 showed an overall structure comparable to that of IMP-1 and other IMP-type enzymes; the positions of the zinc (Zn) ions varied across enzymes. Kinetic analysis showed that IMP-27 had lower catalytic efficiency against penicillins, ceftazidime, cephalexin, and imipenem than IMP-1; however, it had higher affinity and catalytic efficiency against meropenem, especially in the presence of Zn(II). This suggests that the catalytic site of IMP-27 is optimized to hydrolyze meropenem during molecular evolution at the expense of catalytic efficiency against penicillins. However, Zn(II) content analysis after EDTA treatment revealed no significant difference between enzymes. Moreover, analysis of IMP-27 mutants indicated that the differences in kinetic properties and chelator resistance between IMP-1 and IMP-27 were mainly due to an amino acid substitution at position 262. IMPORTANCE The residue at position 262 has been reported as a key determinant of substrate specificity in IMP-type enzymes. Among more than 80 IMP-type metallo-β-lactamase (MBL) variants, IMP-27 was the first reported IMP-type MBL isolated from Proteus mirabilis. This enzyme has a glycine residue at position 262, which is occupied by serine in IMP-1. Compared with IMP-1, IMP-27 had a significantly higher affinity and catalytic efficiency against meropenem and improved metal-binding capacity, maintaining its activity under Zn(II)-limited conditions better than IMP-1. The analysis of the IMP-27 mutants indicated that differences between IMP-27 and IMP-1 were mainly due to an amino acid substitution at position 262. In the case of IMP-27, the G262S mutation optimized the catalytic site of IMP-27 for meropenem hydrolysis, at the expense of catalytic efficiency against penicillins.

Asian cities are exposed to dynamic changes in their historic urban landscapes (HULs). However, the ways in which to quantify the degree of landscape change to guide spatial management have remained underexplored. Taking rapidly changing Hàng Buồm Street, Hanoi, Vietnam, as case study, we developed a numerical score for HULs to capture change tendencies. From onsite surveys, we defined the intensity and speed of change in trade and façades and identified vulnerable spots by mapping the scores for 131 units in 2015, 2017, and 2019. Our results showed that superficial façade changes happened regardless of the degree of trade change, and that the intense façade and trade changes happened around junctions with heavily touristified streets. We also found that aside from conventional tourism, newly emerging nighttime economies, wellness tourism, and multifunctional complexes had more intense façade changes. Based on these findings, we propose refining current management strategies by preparing stricter guidelines to control the aforementioned highly influential trades, establishing urban design project for old street to improve management of junctions especially with heavily touristified streets, and providing detailed examples of appropriate signboards that can easily be referenced by merchants and investors.

Autoclaved lightweight aerated concrete (ALC) panels are utilized as exterior walls due to their lightweight and good insulation properties, especially in Japan. In the ALC panels, the mounting hardware plays a crucial role in connecting the ALC panels with the foundation or structural components and providing resistance to wind and earthquake loads. Thus, the strength of connections is a critical factor in determining the overall stability and safety of the ALC panels. However, there is a lack of studies on the connections. Considering this research gap, an experimental study was conducted to investigate the mechanical behavior of connection in ALC panels.

In this study, we evaluate a subsidy program that reduces urban fire risk. Using apartment auction data from Osaka, Japan, we employ econometric models of first-price sealed-bid auctions to assess the program’s benefits. The data include the attributes of the auctioned apartments, reserve prices, and number of observed bids as well as the highest, second-highest, and third-highest bids. In our analysis, we use the affiliated private value (APV) model to infer the bidder’s valuation. We model affiliation using the Archimedean copula and parametric marginals. To estimate the parameters of the copulas and parametric marginals, we use moment conditions that are satisfied by observed and equilibrium bids when our model specification is correct. We apply the method of simulated moments to the moment conditions. Overidentification and goodness-of-fit tests reject the independent private value (IPV) models, although some APV models are not rejected. Our hypothetical policy evaluation suggests that the subsidy program has a reasonable effect. We note that IPV models under- or overestimate the benefit of the policy when the reduction in fire risk is not only non-marginal but also marginal.

This study investigated plating bath additive effects on the improvement of electroless Ni-Sn plating film resistance against aqueous sodium hypochlorite solutions. Surfaces of conventional electroless Ni-Sn coatings show numerous cracks and pinholes. Through these gaps, a sodium hypochlorite aqueous solution can corrode the substrate, thereby decreasing the chemical resistance of the plated coating. A plating solution bath to which a combination of thiourea and hydroquinone had been added reduced the internal stress of the plating film, suppressed the rate of crack formation on the film surface, and reduced pinhole formation. Findings also revealed that the resultant film had higher resistance than conventional Ni-Sn films.

The oppressive or vibratory sensation caused by low-frequency sound is a widely known sensation inherent to that type of sound. In previous studies using one-third octave band noise as stimuli, the frequency region that causes the oppressive or vibratory sensation was felt before other sensations such as loudness and noisiness (here, called the peculiar region). However, it has been suggested that level fluctuations of one-third octave band noise affect the oppressive or vibratory sensation. Furthermore, few studies have investigated the threshold of these sensations. In the present study, we conducted laboratory experiments to investigate the peculiar region from 10 to 160 Hz as well as the sensation threshold by using low-frequency pure tones. The peculiar region in which the oppressive or vibratory sensation became dominant was generally consistent with the findings of previous studies. However, differences were found in relatively higher frequencies such as 80 and 160 Hz. In addition, the median threshold value was lower than the lowest level of the peculiar region. The threshold differed greatly among the participants, and the higher the frequency, the more pronounced the difference. Multiple regression analysis suggested that these individual differences might be related to noise sensitivity.

A locomotor system that can function across different environmental conditions and produce a range of performances is one of the most critical abilities needed for extant and extinct animals in order to survive and maximise their competitive fitness. Recent engineering-inspired paleontological studies have reconstructed feasible locomotor patterns in extinct animals. However, it is still challenging to describe how extinct animals successfully adjust their locomotor patterns to new situations (e.g., changes in locomotor speed and morphology). In this study, we develop a novel reconstruction method based on a bio-inspired control system. We focus on plesiosaurs, an extinct aquatic reptile group which has two pairs of flipper-shaped limbs, and demonstrate that a highly optimised, flexible locomotor pattern for all four flippers can be reconstructed based on a decentralized control scheme formulated from extant animals’ locomotion. The results of our robotic experiments show that a simple, local sensory feedback mechanism allows the plesiosaur-like robot to exploit the fluid flow between the flippers and generate efficient swimming patterns in response to changes in locomotor conditions. Our new method provides further evidence how decentralized control systems can produce a pathway between extinct and extant animals in order to understand the how extinct animals moved and how these movement patterns may have evolved.

Aluminosilicate (Al‐SiO2) thin films with vertically aligned mesochannels were successfully synthesized on Indium Tin Oxide (ITO) electrodes and employed for the immobilization of a cationic Ru(II) water oxidation catalyst without requiring linker groups. Optimal synthesis conditions yielded uniform mesoporous Al‐SiO2 films with tunable Al content, high surface area (568 m²/g), 3.94 nm pore size, and 155 nm thickness. Electrochemical studies confirmed the presence of the immobilized Ru complex undergoing diffusion‐controlled Ru(III/II) and Ru(IV/III) electron transfer. The Ru loading reached 4.71 nmol/cm² at Si/Al=9.6, with higher Al content enhancing loading amounts via cation exchange. The Ru‐modified electrode exhibited high electrocatalytic water oxidation activity, achieving 75.3 % Faradaic efficiency and a turnover number of 298.6 for O2 evolution for 1 hour. This work provides a new approach to construct porous environments on an electrode surface to immobilize positively charged transition‐metal complexes as catalysts, offering potential applications in the development of electrocatalytic systems for energy conversion.

A multi-finger robotic hand with an iris mechanism that we previously developed was driven by a single actuator and could grasp an object by wrapping fingers completely around its circumference at multiple points. However, the blades used to grasp objects were within the robotic hand mechanism, so it could only grasp objects small enough to fit within the hollow disk comprising the outer surface of the device body. Furthermore, the hand could not grasp objects smaller than the thickness of the hollow disk. The multi-fingered robotic hand proposed in this study has a new mechanism in which the blades of the iris are placed outside of the hand mechanism, and fingers shaped as equilateral triangular prisms extend perpendicular to the disk of the robotic hand body and are attached to the blade tip. Placing the blade outside the mechanism and adjusting the gear ratios within allows adjustments to the gripping torque and speed. The vertically extended fingers can thus grasp small objects and objects longer than the blade diameter. In this study, we performed geometric and theoretical analyses of the proposed multi-fingered robotic hand. We then fabricated an actual robotic hand, verified the validity of the analyses.

The tourism industry plays a pivotal role in the local economies of island communities and offers many attractive activities for tourists. As public transportation tends to be less developed in such island regions, one of the main modes of transportation is rental cars. The supply of rental cars is limited, and tourism demand tends to be seasonal in the island regions. In addition, there is a possibility that some customers may not use rental cars regardless of the price, and others may not make reservations if it is the season when rental cars can be rented without reservations. Therefore, car rental companies need to develop products that match the demand situation, such as peak season and off-season, and tourist characteristics during the seasons to improve profitability. However, little attention has been paid in the academic community to seasonal changes in customers’ car rental reservation behavior in islands. This study investigated the changes in customers’ rental car reservation behavior during the peak and off-peak seasons on Shodoshima Island, Japan, using a questionnaire survey. The results indicated that there are three factors that affect reservation behavior and that there are four patterns of reservation changes depending on the combination of these factors. By comparing the characteristics of segmented groups with different patterns of reservation change, it is suggested that a dynamic change in rental car reservation behavior occurs around retirement age in Japan. The results of this study provide insights into product development to improve the profitability of the tourism industry in island regions.

Skeletal muscle has a high regenerative ability and maintains homeostasis by rapidly regenerating from frequent damage caused by intense exercise or trauma. In sports, skeletal muscle damage occurs frequently due to intense exercise, so practical methods to promote skeletal muscle regeneration are required. Recent studies have shown that it may be possible to promote skeletal muscle regeneration through new pathways, such as promoting autophagy and improving mitochondrial function. Spermidine is a type of polyamine, and oral intake of spermidine promotes autophagy and improves mitochondrial function without inhibiting mTOR. Therefore, we evaluate the effects of spermidine intake on skeletal muscle regeneration after injury using a mouse model of cardiotoxin‐induced muscle injury. Our results showed no significant change in skeletal muscle wet weight with spermidine intake at all time points. In addition, although spermidine intake significantly increased the mean fiber cross‐sectional area 14 days after injury, these effects were not observed at other time points. In addition, we analyzed stem cells, autophagy, mTOR signaling, inflammation, and mitochondria, but no significant effects of spermidine intake were observed at almost all time points and protein expression levels. Therefore, spermidine intake does not affect skeletal muscle regeneration after chemical injury, and if there is any, it is very limited.