• The KIPS Transactions:PartC
• /
• v.11C no.1
• /
• pp.63-74
• /
• 2004

Temporal locality of Web server references is one of the important characteristics to be considered in the design of a Web caching strategy, and it is important to measure the temporal locality exactly. Various methods to estimate the temporal locality have been proposed, however, Web server designers have still troubles in its measurement by using the tools that don't reflect the interarrival time of document requests. In this paper, we propose a measurement tool for short-term temporal locality based on request interarrival time, and discuss the simulation results based on the flares from NLANR and NASA Web sites. The results show that the proposed tool estimates the short-term temporal locality more exactly than that based on a stack.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.13 no.4
• /
• pp.165-170
• /
• 2011

The ambient concentrations of nitrogen dioxide ($NO_2$) at 65 forest areas were measured every month using passive diffusive samplers from 2002 to 2009 and were compared to those at urban areas in order to investigate the characteristics of temporal and spatial distributions of $NO_2$ from the forest and urban areas. The annually averaged concentrations of $NO_2$ gradually decreased for both areas. The average concentration of $NO_2$ in the forest areas was 8.0 ppb, which was lower than that in the urban areas (i.e., 19.4 ppb) and the ecological standard level of the European Union (i.e., 14.6 ppb). The monthly average of $NO_2$ concentration depicted seasonal variations particularly in the urban areas, showing higher concentration in winter and lower concentration in summer. Strong locality of $NO_2$ concentration distribution illustrates that the locations near the metropolitan areas (e.g., Gyeonggi and Chungnam provinces) had the highest concentration during the measurement period. A significant positive correlation between $NO_x$ emissions and $NO_2$ concentration was observed, suggesting that the magnitude and proximity to sources of atmospheric nitrogen oxides would be important controlling factors.