On Relationship between Ergodic Sojourn Time and Ergodic Residual Exit Time for Semi-Markov Processes

For Markov chains in continuous time Keilson(1979) has shown thatthe relationship between the ergodic exit time TE and the ergodic sojourn timeTV is identical to the relationship between the residual lifetime and the underlyinglifetime at ergodicity in renewal theory. Keilson’s result relies upon the memorylessproperty of exponential distributions, and it would not hold true, in general,for semi-Markov processes. The purpose of this paper is to introduce a new performancemeasure called the ergodic residual exit time TW so as to prove thatthe relationship between TW and TV for semi-Markov processes is identical to therelationship between TE and TV for Markov chains in continuous time

Development and Analysis of Stochastic Models for Assessing the Impact of Mobile Devices on e-Business

筑波大学 (University of Tsukuba)201

Enhancement of e-commerce via mobile accesses to the Internet

journal articl

Development of Algorithms for Estimating Apartment Rents in Metropolitan Area Based on a Combined Micro-Macro Approach

Information about the rental costs of the large apartment buildings is asymmetric in that thereal estate companies tend to disclose such information to a customer only for the large apartmentbuildings of potential interest to the customer, and any information irrelevant to the ongoing businesswould be sealed. This information imbalance prevents the market to be transparent, and theeconomic market principles are often ignored. In order to overcome this pitfall, this paper aims atdeveloping a numerical algorithm for estimating the unit rent of a large apartment building based ona set of real data in the metropolitan Tokyo. The algorithm is based on the combined micro-macroapproach, where the local information such as the nearest rail station, the distance to it, and the likewould be used first to estimate the unit rent through the micro approach. For the macro approach,the linear regression is employed based on the real data, and the resulting estimation formula wouldyield the second estimate. The two estimates would then be linearly combined, where the optimalweighting factor would be determined so as to minimize the discrepancy between the combinedestimated values and the unit rents obtained from the real data

Galactic structure studies with BATC star counts

We report the first results of star counts carried out with the National Astronomical Observatories (NAOC) 60/90 cm Schmidt Telescope in 15 intermediate-band filters from 3000 to 10000 {\AA} in the BATC survey. We analyze a sample of over 1400 main sequence stars ($14\le$V$\le21$), which lie in the field with central coordinates R.A.=$09^h53^m13^s.30$ and DEC=47$^\circ49^{\prime}00^{\prime\prime}.0$ (J2000). The field of view is 0.95 deg$^{2}$, and the spatial scale was 1\arcsec.67. In our model, the distribution of stars perpendicular to the plane of the Galaxy is given by two exponential disks (thin disk plus thick disk) and a de Vaucouleurs halo. Based on star counts, we derive the scale heights of the thin disk to be $320^{+14}_{-15}$ pc and of the thick disk to be $640^{+30}_{-32}$ pc, respectively, with a local density of $7.0\pm1$ of the thin disk. We find that the observed counts support an axial ratio of $c/a\le0.6$ for a de Vaucouleurs $r^{1/4}$ law, implying a more flattened halo. We also derive the stellar luminosity function (SLF) for the thin disk, and it partly agrees with the Hipparcos luminosity function.Comment: 17pages,9 figure

Solubility, Discoloration, and Solid-State ¹³C NMR Spectra of Stereoregular Poly(Vinyl Chloride) Prepared by Urea Clathrate Polymerization at Low Temperatures

Stereoregular poly(vinyl chloride) (PVC) was obtained by urea clathrate polymerization. The sample was a white crystalline powder. Its molecular structure was studied by appearance, FT-IR, WAXD, and NMR (solid) in comparison with those of ordinary free radical one. The sample was totally insoluble to polar solvent such as DMF in contrast with good solubility of free radical one. Prolonged heating at high temperatures ensured discoloration and elimination reaction permitted formation of trans-type double bond. This structural change was traced by FT-IR and solid-state NMR. Two non-compromise characteristics, stiff molecular chain and easy discoloration, in canal PVC are described