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This paper proposes S-MAC, a medium access control (MAC) protocol designed for wireless sensor networks. Wireless sensor networks use battery-operated computing and sensing devices. A network of these devices will collaborate for a common application such as environmental monitoring. We expect sensor networks to be deployed in an ad hoc fashion, with nodes(More)
Energy is a critical resource in sensor networks. MAC protocols such as S-MAC and T-MAC coordinate sleep schedules to reduce energy consumption. Recently, lowpower listening (LPL) approaches such as WiseMAC and B-MAC exploit very brief polling of channel activity combined with long preambles before each transmission, saving energy particularly during low(More)
It is widely known that in wireless sensor networks (WSN), energy efficiency is of utmost importance. WSN need to be energy efficient but also need to provide better performance, particularly latency. A common protocol design guideline has been to trade off some performance metrics such as throughput and delay for energy. This paper presents a novel MAC(More)
This paper explores applications and challenges for underwater sensor networks. We highlight potential applications to off-shore oilfields for seismic monitoring, equipment monitoring, and underwater robotics. We identify research directions in short-range acoustic communications, MAC, time synchronization, and localization protocols for high-latency(More)
The goal of this paper is understand how location-dependent propagation latency affects medium access control (MAC) by using ALOHA as a case study. MAC protocols in underwater acoustic networks suffer from latency that is five orders-of-magnitude larger than that in radio networks. Existing work on analyzing MAC throughput in RF networks, where the(More)
This paper introduces T-Lohi, a new class of distributed and energy-efficient media-access protocols (MAC) for underwater acoustic sensor networks (UWSN). MAC design for UWSN faces significant challenges. For example, acoustic communication suffers from latencies five orders-of-magnitude larger than radio communication, so a naive CSMA MAC would require(More)
BACKGROUND Margin width has been shown previously to be the most important predictor of local treatment failure after breast conservation for ductal carcinoma in situ (DCIS). METHODS Five variables thought to be associated with local recurrence were evaluated by univariate and multivariate analysis in 455 nonrandomized patients with DCIS treated with(More)
BACKGROUND Despite the National Institutes of Health consensus statement in 1991 that breast-conserving surgery (BCS) followed by radiotherapy is an appropriate approach to the treatment of early-stage breast carcinoma, studies have shown a relatively low rate of BCS in the United States. The current study investigated predictors of breast conservation(More)
The Polycomb Repressive Complex 2 (PRC2) mediates epigenetic gene silencing by trimethylating histone H3 lysine 27 (H3K27me3) and is known to aberrantly silence tumor suppressor genes in cancer. EZH2, the catalytic subunit of PRC2, enhances tumorigenesis and is commonly overexpressed in several types of cancer. Our microRNA profiling of bladder transitional(More)