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This paper addresses the target coverage problem in wireless sensor networks with adjustable sensing range. Communication and sensing consume energy, therefore efficient power management can extend network lifetime. In this paper, we consider a large number of sensors with adjustable sensing range that are randomly deployed to monitor a number of targets.(More)
This paper addresses the target coverage problem in wireless sensor networks with adjustable sensing range. Communication and sensing consume energy, therefore efficient power management can extend network lifetime. In this paper, we consider a large number of sensors with adjustable sensing range that are randomly deployed to monitor a number of targets.(More)
A major concern in wireless sensor networks is to maximize network lifetime (in terms of rounds) while maintaining a high quality of services (QoS) at each round such as target coverage and network connectivity. Due to the power scarcity of sensors, a mechanism that can efficiently utilize energy has a great impact on extending network lifetime. Most(More)
Recently, opportunistic routing (OR) has been widely used to compensate for the low packet delivery ratio of multi-hop wireless networks. Previous works either provide heuristic solutions without optimality analysis, or assume that unlimited retransmission is available for delivering a data packet. In this paper, we apply OR to a utility-based routing where(More)
Carpooling has long held the promise of reducing gas consumption by decreasing mileage to deliver co-riders. Although <i>ad hoc</i> carpools already exist in the real world through private arrangements, little research on the topic has been done. In this paper, we present the first systematic work to design, implement, and evaluate a carpool service, called(More)
The sulfur content of diesel fuel is of environmental concern because sulfur can facilitate the formation of diesel particulate matter (DPM) and sulfur dioxide (SO2) in the exhaust can poison catalytic converters. The US Environmental Protection Agency (EPA) has established more stringent regulations to reduce the sulfur content of diesel fuels in the near(More)
Chemical graphitized r-GOs, as the thinnest and lightest material in the carbon family, exhibit high-efficiency electromagnetic interference (EMI) shielding at elevated temperature, attributed to the cooperation of dipole polarization and hopping conductivity. The r-GO composites show different temperature-dependent imaginary permittivities and EMI(More)
<b>Introduction</b> Carbon Monoxide (CO) is a poisonous air pollutant produced from the incomplete oxidation of carbon during the combustion process. It has a direct effect on the human body due to its affinity for blood hemoglobin, which inhibits the absorption of oxygen to the blood. The formation of carboxyhemoglobin complex can profoundly affect human(More)
Esterification pretreatment of free fatty acid in biodiesel production, from laboratory to industry" (2014). a b s t r a c t a r t i c l e i n f o Keywords: Acid-catalyzed esterification Biodiesel Used cooking oil Free fatty acid Methanol to FFA ratio Optimization In the US, biodiesel producers usually follow the 19.8:1 methanol-to-FFA molar ratio for free(More)