Tangled String for Multi-Scale Explanation of Contextual Shifts in Stock Market

The original research question here is given by marketers in general, i.e., how to explain the changes in the desired timescale of the market. Tangled String, a sequence visualization tool based on the metaphor where contexts in a sequence are compared to tangled pills in a string, is here extended and diverted to detecting stocks that trigger changes in the market and to explaining the scenario of contextual shifts in the market. Here, the sequential data on the stocks of top 10 weekly increase rates in the First Section of the Tokyo Stock Exchange for 12 years are visualized by Tangled String. The changing in the prices of stocks is a mixture of various timescales and can be explained in the time-scale set as desired by using TS. Also, it is found that the change points found by TS coincided by high precision with the real changes in each stock price. As TS has been created from the data-driven innovation platform called Innovators Marketplace on Data Jackets and is extended to satisfy data users, this paper is as evidence of the contribution of the market of data to data-driven innovations.Comment: 16 pages and 7 figures. The author started to write this paper as an extension of the paper [20] in the reference list, but the content came to be changed substantially, not by only minor extension but to a new pape

Study of the Large-scale Temperature Structure of the Perseus Cluster with Suzaku

We report on a study of the large-scale temperature structure of the Perseus cluster with Suzaku, using the observational data of four pointings of 30' offset regions, together with the data from the central region. Thanks to the Hard X-ray Detector (HXD-PIN: 10 - 60 keV), Suzaku can determine the temperature of hot galaxy clusters. We performed the spectral analysis, by considering the temperature structure and the collimator response of the PIN correctly. As a result, we found that the upper limit of the temperature in the outer region is $\sim$ 14 keV, and an extremely hot gas, which was reported for RXJ 1347.5-1145 and A 3667, was not found in the Perseus cluster. This indicates that the Perseus cluster has not recently experienced a major merger.Comment: 17 pages, 25 figures, accepted for Publications of the Astronomical Society of Japan, references adde

AES Cipher Keys Suitable for Efficient Side-Channel Vulnerability Evaluation

This paper investigates pairs of AES-128 cipher keys and plaintexts which result in being ``quiet\u27\u27 in the final round, i.e., whose 128-bit State holds the same bit pattern before and after Round 10. We show that the number of such quiet plaintexts (resulting in Hamming distance 0) for any cipher key is at most 5,914,624, and that there exist exactly 729 cipher keys having such a maximum number. The same holds if ``quiet\u27\u27 is replaced by ``noisy\u27\u27 (which means to have Hamming distance 128). Because such quiet and noisy plaintexts make extreme actions in the final round of the AES encryption, these AES-128 cipher keys are quite useful for AES hardware designers to efficiently evaluate the vulnerabilities of their products, for instance, the performance of their side-channel attack countermeasures