Changes in consumers' behavior when a vertically integrated service is separated —The case of Japanese mobile phone services—

In this paper, I empirically examine the consumer behavior change in the case that the current vertically integrated Japanese mobile phone market was separated by employing the stated preference survey. As a hypothetical vertically separated situation, I assumed the introduction of contents compatibility and handsets compatibility among different mobile phone carriers. My analysis also assumed the introduction of mail address portability. My estimation results yield the following implications: (1) handset compatibility, contents compatibility, and mail address portability reduces consumer's switching costs, and (2) current contents incompatibility is offsetting the network quality difference among carriers.Telecom market, Mobile Phone, Switching costs, Vertically Integrated market, Compatibility, Conjoint analysis, Discrete choice model, Mixed logit model

Which telecom services should be sustained as national minimum services?

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Early evolution of spherical ejecta expanding into the circumstellar matter at ultra-relativistic speeds

We present a new self-similar solution describing early evolution of an ultra-relativistic flow resulting from a collision of homologously expanding spherical ejecta with the circumstellar matter, in which a shock wave propagates in the circumstellar matter while a weak discontinuity propagates in the ejecta at the sound speedComment: 5 pages, 2 figures, accepted for publication in PAS

Estimating switching costs of changing social networking sites

This study's empirical analysis shows that the consumers' switching costs when changing SNS are less than that when changing BB service. SNS switching cost is estimated at JPY 944, while that in BB service is estimated at JPY 2864 (JPY 80 = USD 1 on 21st May 2012). According to these results, the switching cost of the former is approximately one-third of that of the latter. One of the reasons why SNS switching costs are smaller could be because of the current small number of friends on SNS. In this survey, approximately half of the respondents stated that their number of friends on SNS was less than 10

Multi-quark baryons and color screening at finite temperature

We study baryons in SU(N) gauge theories at finite temperature according to the gauge/string correspondence based on IIB string theory. The baryon is constructed out of D5 brane and $N$ fundamental strings to form a color singlet $N$-quark bound state. At finite temperature and in the deconfining phase, we could find $k(<N)$-quark ``baryons''. Thermal properties of such $k$-quark baryons and also of the $N$-quark baryon are examined. We study the temperature dependence of color screening distance and Debye length of the baryon of $k$-quark and $N$-quark. We also estimate the melting temperature, where the baryons decay into quarks and gluons completely.Comment: 16 pages, 12 figure