Fundamental Investigation on Design of Tunnel Steel Arch Supports

For the purpose of contributing to a proper design of tunnel supports with steel arches, it is necessary to clarify their behavior under earth pressure. As a first approach, the authors investigated a method to calculate the deformation of, and the stress in, steel supports subjected to earth pressure. Special attention was paid to the treatment of the passive forces induced, the mechanical characteristics of the ends of these supports, as well as the joints of the members. As a result of theoretical investigations followed by experiments, the authors obtained a method that may be used in practice

Observation of the Behavior of Deuteriums Implanted in Aluminium by Use of the Nuclear Reaction D(³He, p)⁴He

By applying the depth-profiling technique using the nuclear reaction D(³He, p)⁴He, the thermal behavior of deuteriums implanted in aluminium at a depth of 0-2 μm was examined. The behavior of deuteriums depended greatly on the polishing procedures for the sample surface. When the surface was polished on a series of five abrasive papers or finished by diamond paste, the dispersion behavior of deuteriums in aluminium was quite different from that preducted on the basis of ordinary diffusion in homogeneous media. As suggested by Bugeat and Ligeon, it may be explained by the existence of a weak trapping effect against implanted deuteriums. The half-life of the trapped state at 0°C was estimated at about 1.4×10⁴ sec. Once they are released from the trapping sites, they rapidly disperse over the bulk of aluminium with an ordinary diffusivity measured by permeation methods. On the other hand, for the samples whose surface was finished with coarse Al₂O₃, the deuterium implanted at a depth of 0-2 μm had a much smaller dispersibility than those observed for samples which were polished on a series of five abrasive papers or finished by diamond paste. At room temperature the depth profile was almost unchanged, even after a few weeks. A large depth-dependence of the dispersion behavior was observed

Optimal User Weighting Fusion in DWT Domain On-line Signature Verification

The on-line signature verification method in DWT domain has been proposed. Time-varying pen-position signal of the on-line signature is decomposed into sub-band signals by using the DWT. Individual features are extracted as high frequency signals in sub-band. By using the extracted feature, verification is achieved at each sub-band and then total decision is done by combining such verification results. In this paper, we introduce a user weighting fusion into the total decision. Through verification experiments, it is confirmed that there is an optimal weight combination for each user and verifiaction rate can be improved when the optimal weight combination is applied

DWT Domain Multi-matcher On-line Signature Verification System

This paper presents a multi-matcher on-line signature verification system which fuses the verification scores in pen-position parameter and pen-movement angle parameter at decision level. Features of pen-position and pen-movement angle are extracted by the sub-band decomposition using the Discrete Wavelet Transform (DWT). In the pen-position, high frequency sub-band signals are considered as individual features to enhance the difference between a genuine signature and its forgery. On the other hand, low frequency sub-band signals are utilized as the features for suppressing the intra-class variation in the penmovement angle. Verification is achieved by the adaptive signal processing using the extracted features. Verification scores in the pen-position and the pen-movement angle are integrated by using a weighted sum rule to make total decision. Experimental results show that fusion of pen-position and pen-movement angle can improve verification performance

Threshold Equalization for On-Line Signature Verification

In on-line signature verification, complexity of signature shape can influence the value of the optimal threshold for individual signatures. Writer-dependent threshold selection has been proposed but it requires forgery data. It is not easy to collect such forgery data in practical applications. Therefore, some threshold equalization method using only genuine data is needed. In this letter, we propose three different threshold equalization methods based on the complexity of signature. Their effectiveness is confirmed in experiments using a multi-matcher DWT on-line signature verification system

DWT Domain On-line Signature Verification Using Pen-movement Vector

We examine a pen-movement vector parameter to reduce the computational complexity in the on-line signature verification method based on DiscreteWavelet Transform (DWT) and adaptive signal processing. The pen-movement vector is a time-varying signal which is derived from pen-position parameters and is decomposed into sub-band signals by using the DWT. Individual features are extracted as high frequency components in sub-bands. Verification is achieved in each sub-band by using the adaptive signal processing. Total decision for verification is done by combining multiple verification results. Experimental results show that the verification rate using the pen-movement vector parameter is equivalent to that of our conventional method which utilizes the pen-position parameter although computational complexity is reduced to half of that of the conventional method

Multi-matcher on-line signature verification system in DWT domain

This paper presents a multi-matcher on-line signature verification system which fuses the verification scores in pen-position parameter and pen-movement angle parameter at decision level. Features of pen-position and pen-movement angle are extracted by the sub-band decomposition using the Discrete Wavelet Transform (DWT). In the pen-position, high frequency sub-band signals are considered as individual features to enhance the difference between a genuine signature and its forgery. On the other hand, low frequency sub-band signals are utilized as the features for suppressing the intra-class variation in the pen-movement angle. Verification is achieved by the adaptive signal processing using the extracted features. Verification scores in the pen-position and the pen-movement angle are integrated by using a weighted sum rule to make total decision. Experimental results show that fusion of pen-position and pen-movement angle can improve verification performance

DWT Domain On-Line Signature Verification Using the Pen-Movement Vector

In order to reduce the computational complexity of the DWT domain on-line signature verification, the authors propose to utilize the pen-movement vector as an input parameter. Experimental results indicate that the verification rate obtained using the pen-movement vector parameter is equivalent to that obtained by the conventional method, although the computational complexity of the proposed method is approximately half that of the conventional method

The Amphibious Mudskipper: A Unique Model Bridging the Gap of Central Actions of Osmoregulatory Hormones Between Terrestrial and Aquatic Vertebrates

Body fluid regulation, or osmoregulation, continues to be a major topic in comparative physiology, and teleost fishes have been the subject of intensive research. Great progress has been made in understanding the osmoregulatory mechanisms including drinking behavior in teleosts and mammals. Mudskipper gobies can bridge the gap from aquatic to terrestrial habitats by their amphibious behavior, but the studies are yet emerging. In this review, we introduce this unique teleost as a model to study osmoregulatory behaviors, particularly amphibious behaviors regulated by the central action of hormones. Regarding drinking behavior of mammals, a thirst sensation is aroused by angiotensin II (Ang II) through direct actions on the forebrain circumventricular structures, which predominantly motivates them to search for water and take it into the mouth for drinking. By contrast, aquatic teleosts can drink water that is constantly present in their mouth only by reflex swallowing, and Ang II induces swallowing by acting on the hindbrain circumventricular organ without inducing thirst. In mudskippers, however, through the loss of buccal water by swallowing, which appears to induce buccal drying on land, Ang II motivates these fishes to move to water for drinking. Thus, mudskippers revealed a unique thirst regulation by sensory detection in the buccal cavity. In addition, the neurohypophysial hormones, isotocin (IT) and vasotocin (VT), promote migration to water via IT receptors in mudskippers. VT is also dipsogenic and the neurons in the forebrain may mediate their thirst. VT regulates social behaviors as well as osmoregulation. The VT-induced migration appears to be a submissive response of subordinate mudskippers to escape from competitive and dehydrating land. Together with implications of VT in aggression, mudskippers may bridge the multiple functions of neurohypophysial hormones. Interestingly, cortisol, an important hormone for seawater adaptation and stress response in teleosts, also stimulates the migration toward water, mediated possibly via the mineralocorticoid receptor. The corticosteroid system that is responsive to external stressors can accelerate emergence of migration to alternative habitats. In this review, we suggest this unique teleost as an important model to deepen insights into the behavioral roles of these hormones in relation to osmoregulation