Abstract: This paper adopted a Holtek HT66F50, featured with Flash Memory A/D type 8-bit microcontroller (MCU), and connected with a MQ7 gas sensor and ventilation fans on the ceiling to input the level of carbon monoxide (CO) into the MCU for calculating. As the level of CO in the air reaches 100 ppm, the fans will be activated to exhaust CO out to the space; besides, if the level of CO in the air is over 200 ppm, the buzzer will sound indicating “Alarm”. Carbon monoxide detectors on the market can only buzz during alarm and chirp if a trouble is found, and the prices are high; thus, the study focused on designing a low-cost and multi-functional carbon monoxide detector.

Abstract: The delay in serving a request will reduce the benefits of the information retrieved. Hence, it is a prime requirement to reduce the user perceived latency in accessing the web pages from a web site. Prefetching and caching techniques contribute a lot in reducing the user perceived latency. In this work a novel methodology that effectively reduces the web access latency through prefetching and caching is proposed. Seasonal web sites are taken into consideration and Web Objects are clustered based on the frequency of access and these clusters are prefetched and cached to facilitate the users near future requirement. An exhaustive study of effect of increase in size of the cache on hit ratio is made, and the results are analyzed.