P-Cygni type Lyα from starburst galaxies, either nearby galaxies or Lyman Break galaxies, are believed to be formed by galactic outflows such as galactic supershells or galactic superwinds. We develope a Monte Carlo code to calculate the Lyα line transfer in a galactic supershell which is expanding and formed of uniform and dusty neutral hydrogen gas. The escape of Lyα photons from the system is achieved by a number of back-scatterings. A series of emission peaks are formed by back-scatterings. When we observe P-Cygni type Lyα emissions of starforming galaxies, we can usually see merely singly-peaked emission. Hence the secondary and the tertiary emission humps should be destroyed. In order to do this, dust should be spatially more extended into the inner cavity than neutral supershell. We find that the kinematic information of the expanding supershell is conserved even in dusty media. We discuss the astrophysical applications of our results.

This paper is intended to compare between the Bayesian estimate of a failure rate and the failure rate of a mixed distribution. For the sake of simplification, an exponential distribution and a gamma distribution are adopted as a sampling distribution and its natural conjugate prior distribution. The result shows that both the failure rates are being updated using data and they differ in whether they are functions of unobserved future data or not.

Used as a mixing distribution for an unknown Poisson parameter, the gamma distribution leads to the negative binomial distribution. The hyperparameters of the gamma distribution have their own meanings according to what the Poisson parameter represents. Different sources in the randomness of the Poisson parameter give different interpretations of the negative binomial distribution.

A proper performance evaluation of ATM (Asynchronous Transfer Mode) multiplexer is essential for stable management of ATM networks. We model the on/off traffics entering to the ATM switch as a Markov renewal process (MRP) and propose a performance evaluation method of ATM multiplexer by modeling the system as a discrete time MR/D/1/B queueing system, whose input process is the superposed MRP and present a performance analysis by finding CLP(Cell Loss Probability).

한국산 알뾰족반날개속에 대한 분류학적 연구를 수행하였다. 조사된 8종에서 한국산 미기록종은 다음 7ㅈㅇ으로 밝혀졌다. Sepedolhilus amurensis Schilke, S. fimvriatus(Sharp), S. marshami(Stephens), S. simulans Nakne and Sawada, S. suvarmatus Naomi and Matuyama, S. tiialis(Sharp), and S. varicornis(Sharp). 한국산 알뾰족반날개속에 대한 검색표를 작성하였고, 종을 기재하였으며, 진단 형질을 조식하였다.

A modification of the sol-gel method to obtain phase pure superconducting oxides is described. The method starts from organic salts of yttrium, barium and copper, such as acetates, and avoids the sudden and uncontrollable decomposition of the organic fraction which occurs if nitrates are used as starting materials. The aqueous solution obtained with citric acid in an alkaline medium is concentrated under vacuum. The solid so prepared is decomposed at about 300℃ thus giving an oxide precursor containing well dispersed yttrium, barium and copper. Pyrolysis at 850 - 920℃ followed by oxygen annealing gives the superconducting orthorhombic 123 phase. The results of TGA/DTA of the precursor, as well as XRD, electrical and magnetic property measurements on the pyrolysis products are presented and discussed.