Time series quantile regression using random forests

We discuss an application of Generalized Random Forests (GRF) proposed by Athey et al.(2019) to quantile regression for time series data. We extracted the theoretical results of the GRF consistency for i.i.d. data to time series data. In particular, in the main theorem, based only on the general assumptions for time series data in Davis and Nielsen (2020), and trees in Athey et al.(2019), we show that the tsQRF (time series Quantile Regression Forests) estimator is consistent. Davis and Nielsen (2020) also discussed the estimation problem using Random Forests (RF) for time series data, but the construction procedure of the RF treated by the GRF is essentially different, and different ideas are used throughout the theoretical proof. In addition, a simulation and real data analysis were conducted.In the simulation, the accuracy of the conditional quantile estimation was evaluated under time series models. In the real data using the Nikkei Stock Average, our estimator is demonstrated to be more sensitive than the others in terms of volatility, thus preventing underestimation of risk

High-speed High-precision Control of Atomic Force Microscope by Surface Topography Learning Observer

Abstract-Purpose of this paper is realization of high-speed measurement atomic force microscope (AFM) from view point of the control technology without modification of the hardware. Almost commercial AFM, 3D-image is obtained from control input. High-speed imaging is possible if we can design feedback controller which achieves the high-bandwidth servo design. However, we know that it is restricted by bode integral theorem as resonance peak of the plant. For high-speed imaging, our research group proposed surface topography observer which based on the disturbance observer theory. we can locate the pole of the observer without considering of the resonance of the plant. Thus, we succeeded in high-speed imaging by our proposed observer. On the other hand, as the scanning speed of the X scanner becomes faster, the tracking error increases, because the feedback characteristic is same as conventional system. Not only the high-speed imaging but the suppression of the tracking error is important, because the tracking error express the contact force to the sample. Our research group proposed the tracking error suppression methods which are feedforward compensation. This paper describes the dualdirectional type surface topography learning observer. This paper shows our proposed methods which are effective for the high-speed AFM by simulation and experimental results

A Study on the Characteristics at Low Temperature of Welded Polycarbonate

In this study we investigated the tensile characteristics of welded polycarbonate at low temperature. This study intends to clarify the low temperature characteristics of welded part comparing with those of base material. The results of some measurements on the tensile properties from 20°C down to -70℃ are reported and the changes in tensile properties under low temperature atmosphere are discussed. Furthermore, notch and load velocity effects on the brittle fracture tendency are also discussed. Conclusions obtained in this study are summarized as follows; 1) Both welded part and base material of polycarbonate are strengthened at low temperature. 2) Welding joint efficiency of polycarbonate is very good even at low temperature. 3) Notch and load velocity effects are observed both on the base and the welded materials. 4) Correlations are observed between fracture surfaces and mechanical testing results

Feasibility study of superconducting LSM rocket launcher system

A feasibility study is presented concerning an application of a superconducting linear synchronous motor (LSM) to a large-scale rocket launcher, whose acceleration guide tube of LSM armature windings is constructed 1,500 meters under the ground. The rocket is released from the linear launcher just after it gets to a peak speed of about 900 kilometers per hour, and it flies out of the guide tube to obtain the speed of 700 kilometers per hour at the height of 100 meters above ground. The linear launcher is brought to a stop at the ground surface for a very short time of 5 seconds by a quick control of deceleration. Very large current variations in the single-layer windings of the LSM armature, which are produced at the higher speed region of 600 to 900 kilometers per hour, are controlled successfully by adopting the double-layer windings. The proposed control method makes the rocket launcher ascend stably in the superconducting LSM system, controlling the Coriolis force

A Study on the Thin Plate with Carbon Fiber Reinforced Hybrid Composite

In this paper we describe an experimental study, this article is to report fundamental data of constructions attained by carbon fiber reinforced hybrid composite of O.9mm in thickness whose resin base was reinforced. As a result of this series of test and experiments, it was found that; it is possible to attain reinforced resin base of hybrid composite of C.F.R.P. 16 times as much in rigidity against bending load as compared with that of single construction was observed with composite of O.9mm lamina. It was found that sandwich construction of C.F.R.P. is superior, while, in the case of canape construction, it was found necessary to have C.F.R.P. on the tension side. G.F.R.P. has possibility to be reinforced composite material, although it is considerably less superior to C.F.R.P

A Study on the Fatigue Characteristics of Polymethylmetacrylate Adherends

In this paper we describe an experimental study. Reported in this article are tensile fatigue characteristics of polymethylmetacrylate and its bonded material in relation to wave form of load, loading velocity and notch effect. In experiments, heat cured acrylic resin was used for base material, while heat cured and self-cured polymethylmetacrylate (Denture Acrylic SHOFU "Bio" Resin) were used as Adhesives. As a result of the research of test and experiments, it is found that; 1) Fatigue limits of the bonded materials using heat cured and self-cured P.M.M.A. are approximately 2/3 and 1/3 of that of the base material. 225 2) Two-fold property of S-N curve can be seen with dental P.M.M.A., and such property is partly attributable to temperature rise of the test piece. Fatigue limit drops as test velocity increases, and such drop is again partly attributably to temperature rise of the material. 3) Effect of notch is observed and it is noted that the notch causes deterioration in endurance limit by about 1/4

A Study on the Adhesion of the Composite Denture

In this paper we describe an experimental study, in the preceding article, authors reported about the abrasion for composite teeth, in this article are a composite denture which was newly made combining merits of the porcelain and the plastic teeth, a trial production of composite materials of the porcelain and the plastic teeth, and an experimental study of adhesion property of the composite tooth. The following summary can be made from the results of the present experiments. Adhesion of composite denture with filler of porcelain element in principal can be fully expected. In comparison with adhesion strength of P.M.M.A. to P.M.M.A., tensile joint efficiency adhered by P.M.M.A. of heat-cured type was 84-100%, while that of P.M.M.A. of low temperature cured type was 97-98%. Bending joint efficiency using the former adhesive was 87-94%, while that of the latter adhesive was 83-85%

A Study on the Fatigue Characteristics of Polymethylmetacrylate Adherends

In this paper we describe an experimental study. Reported in this article are tensile fatigue characteristics of polymethylmetacrylate and its bonded material in relation to wave form of load, loading velocity and notch effect. In experiments, heat cured acrylic resin was used for base material, while heat cured and self-cured polymethylmetacrylate (Denture Acrylic SHOFU "Bio" Resin) were used as Adhesives. As a result of the research of test and experiments, it is found that; 1) Fatigue limits of the bonded materials using heat cured and self-cured P.M.M.A. are approximately 2/3 and 1/3 of that of the base material. 225 2) Two-fold property of S-N curve can be seen with dental P.M.M.A., and such property is partly attributable to temperature rise of the test piece. Fatigue limit drops as test velocity increases, and such drop is again partly attributably to temperature rise of the material. 3) Effect of notch is observed and it is noted that the notch causes deterioration in endurance limit by about 1/4