Results 1  10
of
16,924
Medium Access Control with Coordinated Adaptive Sleeping for Wireless Sensor Networks
 IEEE/ACM Transactions on Networking
, 2004
"... This paper proposes SMAC, a medium access control (MAC) protocol designed for wireless sensor networks. Wireless sensor networks use batteryoperated computing and sensing devices. A network of these devices will collaborate for a common application such as environmental monitoring. We expect senso ..."
Abstract

Cited by 684 (15 self)
 Add to MetaCart
This paper proposes SMAC, a medium access control (MAC) protocol designed for wireless sensor networks. Wireless sensor networks use batteryoperated 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 remaining largely inactive for long time, but becoming suddenly active when something is detected. These characteristics of sensor networks and applications motivate a MAC that is different from traditional wireless MACs such as IEEE 802.11 in several ways: energy conservation and selfconfiguration are primary goals, while pernode fairness and latency are less important. SMAC uses a few novel techniques to reduce energy consumption and support selfconfiguration. It enables lowdutycycle operation in a multihop network. Nodes form virtual clusters based on common sleep schedules to reduce control overhead and enable trafficadaptive wakeup. SMAC uses inchannel signaling to avoid overhearing unnecessary traffic. Finally, SMAC applies message passing to reduce contention latency for applications that require innetwork data processing. The paper presents measurement results of SMAC performance on a sample sensor node, the UC Berkeley Mote, and reveals fundamental tradeoffs on energy, latency and throughput. Results show that SMAC obtains significant energy savings compared with an 802.11like MAC without sleeping.
An EnergyEfficient MAC Protocol for Wireless Sensor Networks
, 2002
"... This paper proposes SMAC, a mediumaccess control (MAC) protocol designed for wireless sensor networks. Wireless sensor networks use batteryoperated computing and sensing devices. A network of these devices will collaborate for a common application such as environmental monitoring. We expect senso ..."
Abstract

Cited by 1488 (37 self)
 Add to MetaCart
This paper proposes SMAC, a mediumaccess control (MAC) protocol designed for wireless sensor networks. Wireless sensor networks use batteryoperated 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 individual nodes remaining largely inactive for long periods of time, but then becoming suddenly active when something is detected. These characteristics of sensor networks and applications motivate a MAC that is different from traditional wireless MACs such as IEEE 802.11 in almost every way: energy conservation and selfconfiguration are primary goals, while pernode fairness and latency are less important. SMAC uses three novel techniques to reduce energy consumption and support selfconfiguration. To reduce energy consumption in listening to an idle channel, nodes periodically sleep. Neighboring nodes form virtual clusters to autosynchronize on sleep schedules. Inspired by PAMAS, SMAC also sets the radio to sleep during transmissions of other nodes. Unlike PAMAS, it only uses inchannel signaling. Finally, SMAC applies message passing to reduce contention latency for sensornetwork applications that require storeandforward processing as data move through the network. We evaluate our implementation of SMAC over a sample sensor node, the Mote, developed at University of California, Berkeley. The experiment results show that, on a source node, an 802.11like MAC consumes 26 times more energy than SMAC for traffic load with messages sent every 110s.
Symmetry and Related Properties via the Maximum Principle
, 1979
"... We prove symmetry, and some related properties, of positive solutions of second order elliptic equations. Our methods employ various forms of the maximum principle, and a device of moving parallel planes to a critical position, and then showing that the solution is symmetric about the limiting plan ..."
Abstract

Cited by 539 (4 self)
 Add to MetaCart
We prove symmetry, and some related properties, of positive solutions of second order elliptic equations. Our methods employ various forms of the maximum principle, and a device of moving parallel planes to a critical position, and then showing that the solution is symmetric about the limiting plane. We treat solutions in bounded domains and in the entire space.
Risk and protective factors for alcohol and other drug problems in adolescence and early adulthood: Implications for substance abuse prevention
 Psychological Bulletin
, 1992
"... The authors suggest that the most promising route to effective strategies for the prevention of adolescent alcohol and other drug problems is through a riskfocused approach. This approach requires the identification of risk factors for drug abuse, identification of methods by which risk factors hav ..."
Abstract

Cited by 693 (18 self)
 Add to MetaCart
The authors suggest that the most promising route to effective strategies for the prevention of adolescent alcohol and other drug problems is through a riskfocused approach. This approach requires the identification of risk factors for drug abuse, identification of methods by which risk factors have been effectively addressed, and application of these methods to appropriate highrisk and general population samples in controlled studies. The authors review risk and protective factors for drug abuse, assess a number of approaches for drug abuse prevention potential with highrisk groups, and make recommendations for research and practice. In spite of general decreases in the prevalence of the nonmedical use of most legal and illegal drugs in recent years, the abuse of alcohol and other drugs during adolescence and early adulthood remains a serious public health problem (Adams, Blanken, Ferguson, & Kopstein, 1990). The consequences of drug abuse are acute on both a personal and a societal level. For the developing young adult, drug and alcohol abuse undermines motivation, interferes with cognitive processes, contrib
Testing for Common Trends
 Journal of the American Statistical Association
, 1988
"... Cointegrated multiple time series share at least one common trend. Two tests are developed for the number of common stochastic trends (i.e., for the order of cointegration) in a multiple time series with and without drift. Both tests involve the roots of the ordinary least squares coefficient matrix ..."
Abstract

Cited by 455 (7 self)
 Add to MetaCart
Cointegrated multiple time series share at least one common trend. Two tests are developed for the number of common stochastic trends (i.e., for the order of cointegration) in a multiple time series with and without drift. Both tests involve the roots of the ordinary least squares coefficient matrix obtained by regressing the series onto its first lag. Critical values for the tests are tabulated, and their power is examined in a Monte Carlo study. Economic time series are often modeled as having a unit root in their autoregressive representation, or (equivalently) as containing a stochastic trend. But both casual observation and economic theory suggesthat many series might contain the same stochastic trendso that they are cointegrated. If each of n series is integrated of order 1 but can be jointly characterized by k < n stochastic trends, then the vecto representation of these series has k unit roots and n k distinct stationary linear combinations. Our proposed tests can be viewed alternatively as tests of the number of common trends, linearly independent cointegrating vectors, or autoregressive unit roots of the vector process. Both of the proposed tests are asymptotically similar. The firstest (qf) is developed under the assumption that certain components of the process have a finiteorder vector autoregressive (VAR) representation, and the nuisance parameters are handled by estimating this VAR. The second test (q,) entails computing the eigenvalues of a corrected sample firstorder autocorrelation matrix, where the correction is essentially a sum of the autocovariance matrices. Previous researchers have found that U.S. postwar interest rates, taken individually, appear to be integrated of order 1. In addition, the theory of the term structure implies that yields on similar assets of different maturities will be cointegrated. Applying these tests to postwar U.S. data on the federal funds rate and the three and twelvemonth treasury bill rates providesupport for this prediction: The three interest rates appear to be cointegrated.
Study on Measured Data Processing Method of Model Test for Relative Motions between Two Sidebyside Replenishment Ships in Waves Pingan Shi1,2,a and Jiawei Ye1,b
"... Abstract. The method to process measured data of ship model test with contact measurement to study the characteristics of relative motion between two sidebyside ships was investigated. The reference coordinate systems and the relative motions of two sidebyside replenishment ships were defined. ..."
Abstract
 Add to MetaCart
Abstract. The method to process measured data of ship model test with contact measurement to study the characteristics of relative motion between two sidebyside ships was investigated. The reference coordinate systems and the relative motions of two sidebyside replenishment ships were defined. Then the integration transform method which combines Fast Fourier Transform(FFT) with Empirical Mode Decomposition(EMD) selfadaptive filter was applied to transform measured acceleration signal into displacement. The EMD adaptive filter is designed, and the integration results from acceleration to displacement with and without EMD adaptive filter were compared, which shows that the EMD adaptive filter can effectively eliminate the noise embedded in the measured data. At last, the relative motions are acquired, which are consistent with the practical situation.
Inference in Linear Time Series Models with Some Unit Roots," Econometrica
, 1990
"... This paper considers estimation and hypothesis testing in linear time series models when some or all of the variables have unit roots. Our motivating example is a vector autoregression with some unit roots in the companion matrix, which might include polynomials in time as regressors. In the general ..."
Abstract

Cited by 376 (12 self)
 Add to MetaCart
This paper considers estimation and hypothesis testing in linear time series models when some or all of the variables have unit roots. Our motivating example is a vector autoregression with some unit roots in the companion matrix, which might include polynomials in time as regressors. In the general formulation, the variable might be integrated or cointegrated of arbitrary orders, and might have drifts as well. We show that parameters that can be written as coefficients on mean zero, nonintegrated regressors have jointly normal asymptotic distributions, converging at the rate T'/2. In general, the other coefficients (including the coefficients on polynomials in time) will have nonnormal asymptotic distributions. The results provide a formal characterization of which t or F testssuch as Granger causality testswill be asymptotically valid, and which will have nonstandard limiting distributions.
The Hero with a Thousand Faces
, 1972
"... Botiingen Foundation, andpttt.!.,.: b % / ,.,;:,c,m B<,.ik.*, second ..."
Abstract

Cited by 353 (0 self)
 Add to MetaCart
Botiingen Foundation, andpttt.!.,.: b % / ,.,;:,c,m B<,.ik.*, second
WeiYang Lu,* # HengYe Man,ยง#
"... in the trafficking of postsynaptic AMPA receptors would provide an attractive hypothesis. Although incorporation of recombinant AMPA receptor GluR1 subunits into synapses has been demonstrated (Hayashi et al., 2000), ..."
Abstract
 Add to MetaCart
in the trafficking of postsynaptic AMPA receptors would provide an attractive hypothesis. Although incorporation of recombinant AMPA receptor GluR1 subunits into synapses has been demonstrated (Hayashi et al., 2000),
Results 1  10
of
16,924