Statistical mechanical evaluation of spread spectrum watermarking model with image restoration

In cases in which an original image is blind, a decoding method where both the image and the messages can be estimated simultaneously is desirable. We propose a spread spectrum watermarking model with image restoration based on Bayes estimation. We therefore need to assume some prior probabilities. The probability for estimating the messages is given by the uniform distribution, and the ones for the image are given by the infinite range model and 2D Ising model. Any attacks from unauthorized users can be represented by channel models. We can obtain the estimated messages and image by maximizing the posterior probability. We analyzed the performance of the proposed method by the replica method in the case of the infinite range model. We first calculated the theoretical values of the bit error rate from obtained saddle point equations and then verified them by computer simulations. For this purpose, we assumed that the image is binary and is generated from a given prior probability. We also assume that attacks can be represented by the Gaussian channel. The computer simulation retults agreed with the theoretical values. In the case of prior probability given by the 2D Ising model, in which each pixel is statically connected with four-neighbors, we evaluated the decoding performance by computer simulations, since the replica theory could not be applied. Results using the 2D Ising model showed that the proposed method with image restoration is as effective as the infinite range model for decoding messages. We compared the performances in a case in which the image was blind and one in which it was informed. The difference between these cases was small as long as the embedding and attack rates were small. This demonstrates that the proposed method with simultaneous estimation is effective as a watermarking decoder

Iron-catalysed cross-coupling of halohydrins with aryl aluminium reagents: a protecting-group-free strategy attaining remarkable rate enhancement and diastereoinduction.

Non-protected halohydrins are cross-coupled with aryl aluminium reagents to produce aryl alkanols in the presence of the iron-bisphosphine catalysts. Remarkable reaction rate enhancement and diastereoinduction are realized by the in situ generated aluminium alkoxides, offering a new method for the reactivity and selectivity control of the iron-catalysed cross-coupling reaction

The successful strategy for mutual cooperation in the experimental multi-game contact

Playing multiple games simultaneously is popular, but we hardly know how people act in this situation to reach mutual cooperation in the long run. To answer the question, we conduct a series of experiments on multi-game contact. The results indicate that the number of information sets in the stage game and the payoff structure are important. We find that for making mutual cooperation subjects employ two types of TFT strategies, which simplify the complicated contact. In these strategies, they avoid separating behavior such as cooparating in one game but deviating in the other. This makes it easy for the opponents to understand thier cooperative intention

Parameter identification of nonlinear viscoelastic model with impact area parameter for sport surface by using multi-intensity multi-area impact test

AbstractIn previous studies, we proposed various models of material and methods for identifying the parameters of these models by multi-intensity impact test. Especially, the exponential funtion type nonlinear Voigt model shows an excellent accuracy for identifying the property of material behavior. Although other papers show that this model is applicable to the case of varying impact duration and various temperatures, we have not yet discussed how the properties would change as the impact area changed. The purpose of this study is to propose an identification technique of nonlinear Voigt model with hysteresis and dependence on impact area by multi-intensity multi-area impact test. The nonlinear elastic element of this model is expressed by the exponential function based on displacement and impact area. And the nonlinear viscous element of the model is expressed by the product of the exponential function based on displacement and the exponential function based on velocity

A Study on High Efficiency Wing-Vane Compressor - Part.2: Lubrication Characteristic of The Partial Arc Guide Bearing -

Low global warming refrigerants such as HFO (hydro fluoro olefin) -1234yf are attracted as an alternative working fluid in air-conditioning and cooling systems to address global warming. However, it used to require larger compressor size due to the lower fluid density compared with conventional refrigerants such as R410A. Thus, a new wing-vane compressor which has no contraction between the vane and the cylinder is developed to prevent increase in the size without performance degradation. Â Rotary motion of the vane is supported by the partial arc guide on the upper and lower ends of the vane. Revealing the lubricating properties of the guide was one of the development issues. Â So we have analyzed the guide bearing performance such as friction coefficient and oil film thickness with fluid dynamics lubrication model of the guide bearing. And we measured the friction coefficient of the guide bearing by experiment. The analysis model was validated by comparing the simulated friction coefficient and that of experiment. In addition, we examined the effect of the shape of the guide bearing on the lubricating properties. The results are as follows: (1)When the load is applied to the center of the guide arc angle, the friction coefficient of the analysis and experiment result is in good agreement. (2)The friction coefficient of the guide bearing can be organized in Stribeck diagram as well as full journal bearing in the fluid lubrication region

A Study on High Efficiency Wing-vane Compressor - Part.3: Experimental Evaluation of the Prototype -

Low global warming refrigerants such as HFO (hydro fluoro olefin) -1234yf are attracted as an alternative working fluid in air-conditioning and cooling systems to address global warming. However, it used to require larger compressor size due to the lower fluid density compared with conventional refrigerants such as R410A. Thus, a new wing-vane compressor which has no contraction between the vane and the cylinder is developed to prevent increase in the size without performance degradation. The structure of the wing-vane compressor is different from the conventional vane compressor. Therefore, a prototype of the wing-vane compressor was operated using R134a refrigerant to simulate HFO-1234yf refrigerant. The results are as follows: (1) The steady operation is observed in the general operating condition. (2) The steady mechanism of vane is clarified by both experiment and simulation. (3) A simple lubrication structure is achieved by supplying the oil to the friction surface through the grooves with the partial arc guide bearings

新聞記事における慣用表現の出現頻度調査

日本語学習者を対象とした慣用表現の効率的な教育（学習）を実現するため，朝日新聞，毎日新聞，読売新聞の2014 年の記事データベースを対象にして出現頻度の高い慣用表現のリストを作成した．まず，宮地（1982）『慣用句の意味と用法』，森田（2010）『日本語の慣用表現』に掲載された慣用表現に異表記を追加し，6,378 個の慣用表現を得た．次に，3 紙の合計で約490 万文を対象として，慣用表現の出現頻度を計数した．そして，各紙における出現頻度上位100 位のうち，3紙すべてに共通して現れる慣用表現を求めた．これによって，新聞による偏りを排除し，使用頻度が高く学習者に有用な慣用表現リストが得られた