Hitachi Ltd. and Nippon Institute of Technology | Date: 2017-07-12
A ring molded article manufacturing method capable of reliably and efficiently producing a ring molded article in which dead metal regions are reduced, and a ring material used for producing the ring molded article, are provided. The present invention relates to the method for manufacturing a ring molded article having two convex portions which respectively protrude on both sides of the ring molded article in a direction of a center axis thereof and extend in a direction of a circumeference of the ring molded article. In the manufacturing method, the ring material is placed inside two molds on which concave portions respectively corresponding to the convex portions are formed, in a condition in which the ring material is supported by a region on an outer peripheral side from an outer peripheral side corner in the concave portion of one of the two molds and a region on an inner peripheral side from an inner peripheral side corner in the concave portion of another of the two molds, the ring material is then forged so as to be pressed by the two molds in a direction of a center axis of the ring material, and the ring molded article is thus produced. In addition, the present invention relates to the ring material used for producing the ring molded article.
Sato S.-Y.,Nippon Institute of Technology
Proceedings - 2016 IEEE/WIC/ACM International Conference on Web Intelligence, WI 2016 | Year: 2016
Structural analysis of networks has attracted a lot of attention from researchers. While previous studies have devised structural indices for quantitatively describing network structures, they mostly focus on specific structural characteristics and the structural information provided by them is often fragmental. This paper proposes methods for representing and analyzing structural characteristics of networks that provide a comprehensive understanding of network structure. It describes a new approach for grasping the structural features of networks, wherein a signal is input at a vertex of a given network, and the signal propagates through the network and eventually returns to the input vertex through various routes. The returning signal at the input vertex can be thought of as the response of the network to the input signal and can be used as a representation of the structural characteristics of the network that can be analyzed using existing signal analysis techniques. The paper also describes experiments examining the properties of response signals in artificial networks and presents a method for identifying the structural characteristics of a network by analyzing its response signal. © 2016 IEEE.
Yamazaki A.K.,Shibaura Institute of Technology |
Eto K.,Nippon Institute of Technology
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011
A previous study of the effects of background colors on the scores of a computer-based English test indicated that a combination of black text and a background color with high luminance and high brightness, such as white or yellow, was not considered preferable for computer-based tests (CBTs). In this study, the authors conducted an experiment to see how a background color can affect the brain functions of CBT test takers by observing relative changes in hemoglobin (Hb) concentrations in their brains by using near-infrared spectroscopy. In the experiment, seven male subjects in their twenties took computer-based English tests with different background colors with black text. Two dimensional images of the Hb concentration changes obtained in the experiment showed that areas in the brain associated with memory retrieval tended to have higher Hb concentrations while the subjects were taking the tests with blue backgrounds. On the other hand, areas in the brain related to other functions, such as the frontal eye field, were observed to be more active than brain areas responsible for cognitive tasks while they were taking the test with white background. These results suggest that white color may not be the best choice for a background color of a CBT, in terms of activating brain functions associated with linguistic tasks, even though a white background is commonly used for CBTs. © 2011 Springer-Verlag.
Haga K.,Nippon Institute of Technology |
Hayashi K.-I.,Okayama University of Science |
Sakai T.,Niigata University
Plant Physiology | Year: 2014
Several members of the AGCVIII kinase subfamily, which includes PINOID (PID), PID2, and WAVY ROOT GROWTH (WAG) proteins, have previously been shown to phosphorylate PIN-FORMED (PIN) auxin transporters and control the auxin flow in plants. PID has been proposed as a key component of the phototropin signaling pathway that induces phototropic responses, although the responses were not significantly impaired in the pid single and pid wag1 wag2 triple mutants. This raises questions about the functional roles of the PID family in phototropic responses. Here, we investigated hypocotyl phototropism in the pid pid2 wag1 wag2 quadruple mutant in detail to clarify the roles of the PID family in Arabidopsis (Arabidopsis thaliana). The pid quadruple mutants exhibited moderate responses in continuous light-induced phototropism with a decrease in growth rates of hypocotyls and normal responses in pulse-induced phototropism. However, they showed serious defects in enhancements of pulse-induced phototropic curvatures and lateral fluorescent auxin transport by red light pretreatment. Red light pretreatment significantly reduced the expression level of PID, and the constitutive expression of PID prevented pulse-induced phototropism, irrespective of red light pretreatment. This suggests that the PID family plays a significant role in phytochrome-mediated phototropic enhancement but not the phototropin signaling pathway. Red light treatment enhanced the intracellular accumulation of PIN proteins in response to the vesicle-trafficking inhibitor brefeldin A in addition to increasing their expression levels. Taken together, these results suggest that red light preirradiation enhances phototropic curvatures by upregulation of PIN proteins, which are not being phosphorylated by the PID family. Ó 2014 American Society of Plant Biologists. All rights reserved.
Thipprakmas S.,King Mongkut's University of Technology Thonburi |
Thipprakmas S.,Nippon Institute of Technology
Materials and Design | Year: 2010
Considering the advantages of the V-bending die, the economical set-up time and the fabrication of a wide range of part size and complex shape, the V-bending die is generally used, especially in the Press Brake machine. However, the punch heights in the partial V-bending die affected the bending angle. In this study, the finite element method (FEM) was used to investigate the effects of punch height. The FEM simulation results revealed that the effects of punch height on the bending angle were clearly theoretically clarified based on the material flow analysis and stress distribution. The punch height affected the gap between the workpiece and the die, as well as the reversed bending zone, which resulted in a non-required bending angle. Therefore, applying a suitable punch height created a balance of compensating the gap between the workpiece and the die, and the stress distribution on the bending allowance and the reversed bending zone. This resulted in achieving the required bending angle. © 2009 Elsevier Ltd. All rights reserved.
Miyake S.,Nippon Institute of Technology |
Yamazaki S.,Nippon Institute of Technology
Wear | Year: 2013
Scratch properties of extremely thin (targeted at 0.03-5.0-nm-thick) diamond-like carbon (DLC) films deposited by the filtered cathodic vacuum arc (FCVA) and electron cyclotron resonance chemical vapor deposition (ECR-CVD) methods are investigated. The difference in profiles and friction coefficients of scratches in both the corn and edge directions are evaluated. The difference of scratch properties between deposition methods is clearly evaluated by the scratching in the corn direction. When scratching in the corn direction, the friction coefficient and wear depth of the FCVA-DLC film increased rapidly at critical load, whereas those of the ECR-CVD-DLC film increased gradually even beyond this critical load. These results are deduced to be caused by the differences in the hardness and brittleness of the films. The dependence of nanoscratch friction force and scratch profile on DLC film thickness can reveal differences in mechanical properties that correspond to atomic-scale thickness. © 2013 Elsevier B.V.
Kambayashi Y.,Nippon Institute of Technology
Algorithms | Year: 2013
A survey on the routing protocols based on ant-like mobile agents is given. These protocols are often employed in Mobile Ad Hoc Networks (MANET). Mobile Ad Hoc Networks are collections of wireless mobile nodes such as PDAs, laptop computers, and cellular phones having wireless communication capability that dynamically form a temporary network without using any existing network infrastructures such as wireless access points. The only infrastructure in MANET is the wireless communication interfaces on the devices. In such a circumstance, where some of the wireless devices are not within wireless range of each other, multi-hop routing is required to transmit messages to the destination. A node that wants to start communication with other nodes that are not within its one-hop wireless transmission range has to request intermediate nodes to forward their communication packets to the destination. In this paper, we survey a variety of proposed network protocols to accommodate this situation. We focus especially on biologically-inspired routing algorithms that are based on the ant colony optimization algorithm. © 2013 by the authors.
Ogawa T.,Nippon Institute of Technology |
Kambayashi Y.,Nippon Institute of Technology
ACHI 2012 - 5th International Conference on Advances in Computer-Human Interactions | Year: 2012
Certain sports such as martial arts and dance have sets of good typical motion types. These motion types were abstracted from the physical movements of excellent practitioners. They are devised for instruction purpose, and are optimal movements of the target sports. It is extremely important for learners to learn these typical motion types. Traditionally the transfer of such typical motion types is done by in-person instructions. Therefore it is considered that it is not suitable for distance learning environment. We have developed a support system to convey this motion types by way of communication networks. In this paper, we propose a real-time physical instructional support system. The instructor and the learners communicate with each other by the virtual humanoid 3D-CG avatars through the Internet. By using this system, it is possible for the instructor to demonstrate his motions, and for learners to obtain the instructor's movements at distant places. The obtained information is beyond simple camera images. Because the system provides the three-dimensional perspectives and it superimposes the instructor's movements on the learner's avatars as well as provides a means of real-time direct communication. Copyright © IARIA, 2012.
Suzuki H.,Nippon Institute of Technology
Procedia Computer Science | Year: 2013
This study applies a particle filter (PF) and an unscented Kalman filter (UKF) to estimate the headway and velocity of a six- vehicle platoon system. These two feedback estimators were used to estimate headway and velocity indirectly from several measurement variables, such as acceleration rate and velocity, of selected vehicles in the platoon. To evaluate the performance of the proposed two estimators, artificial car-following data were created to cover various speed ranges that include some acceleration and deceleration scenarios. Also, a comparison of estimation accuracy is conducted when varying the number of probe cars installed in the platoon system. Numerical analysis showed that the PF succeeded in estimating headway and velocity more accurately than the UKF, even when the number of probe cars installed is fewer and their location is varied within the platoon. The estimations by the UKF were inaccurate and the filter was unstable during all probe car penetrations except during the 100% installation scenario. The UKF is considered to yield stable and accurate estimates only when all vehicles are equipped with the sensing system, whereas the PF does not require numerous probe cars to generate accurate estimates regardless of their location in the platoon. © 2013 The Authors.
Miyake S.,Nippon Institute of Technology |
Yamazaki S.,Nippon Institute of Technology
Wear | Year: 2014
In order to enable higher density recording, a better understanding of the magnetic disk/head interface is required. Therefore, the nanowear properties of extremely thin diamond-like carbon (DLC) films deposited on a Si(1. 0. 0) surface via filtered cathodic vacuum arc (FCVA) and electron cyclotron resonance-chemical vapor deposition (ECR-CVD) methods were evaluated using atomic force microscopy. It is proposed that tribochemical reactions led to the formation of protuberances on the thin DLC films coated on Si substrates. However, the FCVA-DLC films were more resistant to these tribochemical reactions of Si than the ECR-CVD-DLC films. For both 1.5-nm-thick ECR-CVD-DLC and 0.8-nm-thick FCVA-DLC films, the film was removed even at low loads, and the protuberances increased with the load because of direct contact between the diamond tip and the Si surface. Diamond tip sliding at higher loads also removed thicker ECR-CVD-DLC films, while thicker FCVA-DLC films remained on the Si surface and prevented tribochemical reactions. Furthermore, thicker ECR-CVD-DLC films exhibited deeper wear depths than FCVA-DLC films. These results reveal the differences in the resistance to wear and tribochemical reactions of extremely thin DLC films prepared using different deposition methods and confirm the superior properties of FCVA-DLC films. © 2014 Elsevier B.V.