6,495 research outputs found
Wireless Heterogeneous Networks and Next Generation Internet
The recent advances in wireless access technologies as well as the increasing number of mobile applications have made Wireless Internet a reality. A wide variety of bandwidth demanding services including high speed data delivery and multimedia communication have been materialized through the convergence of the next generation Internet and heterogeneous wireless networks. However, providing even higher bandwidth and richer applications necessitates a fundamental understanding of wireless Internet architecture and the interactions between heterogeneous users. Consequently, fundamental advances in many concepts of the wireless Internet are required for the ultimate goal of communication anytime anywhere.
This special issue of the ACM Mobile Networks and Applications Journal is dedicated to the recent advances in the area of Wireless Internet. We accepted 10 papers out of 59 submissions from all over the world with a 17% acceptance rate. Papers describing management schemes, protocols, models, evaluation methods, and experimental studies of Wireless Internet are included in this special issue to provide a broad view of recent advances in this field
Identification of an appropriate low flow forecast model\ud for the Meuse River
This study investigates the selection of an appropriate low flow forecast model for the Meuse\ud
River based on the comparison of output uncertainties of different models. For this purpose, three data\ud
driven models have been developed for the Meuse River: a multivariate ARMAX model, a linear regression\ud
model and an Artificial Neural Network (ANN) model. The uncertainty in these three models is assumed to\ud
be represented by the difference between observed and simulated discharge. The results show that the ANN\ud
low flow forecast model with one or two input variables(s) performed slightly better than the other statistical\ud
models when forecasting low flows for a lead time of seven days. The approach for the selection of an\ud
appropriate low flow forecast model adopted in this study can be used for other lead times and river basins\ud
as well
Identification of appropriate temporal scales of dominant low flow indicators in the Main River, Germany
Models incorporating the appropriate temporal scales of dominant indicators for low flows are assumed to perform better than models with arbitrary selected temporal scales. In this paper, we investigate appropriate temporal scales of dominant low flow indicators: precipitation (P), evapotranspiration (ET) and the standardized groundwater storage index (G). This analysis is done in the context of low flow forecasting with a lead time of 14 days in the Main River, a tributary of the Rhine River, located in Germany. Correlation coefficients (i.e. Pearson, Kendall and Spearman) are used to reveal the appropriate temporal scales of dominant low flow indicators at different time lags between low flows and indicators and different support scales of indicators. The results are presented for lag values and support scales, which result in correlation coefficients between low flows and dominant indicators falling into the maximum 10% percentile range. P has a maximum Spearman correlation coefficient (Ï) of 0.38 (p = 0.95) at a support scale of 336 days and a lag of zero days. ET has a maximum Ï of â0.60 (p = 0.95) at a support scale of 280 days and a lag of 56 days and G has a maximum Ï of 0.69 (p = 0.95) at a support scale of 7 days and a lag of 3 days. The identified appropriate support scales and lags can be used for low flow forecasting with a lead time of 14 days
Real-Time Online Re-Planning for Grasping Under Clutter and Uncertainty
We consider the problem of grasping in clutter. While there have been motion
planners developed to address this problem in recent years, these planners are
mostly tailored for open-loop execution. Open-loop execution in this domain,
however, is likely to fail, since it is not possible to model the dynamics of
the multi-body multi-contact physical system with enough accuracy, neither is
it reasonable to expect robots to know the exact physical properties of
objects, such as frictional, inertial, and geometrical. Therefore, we propose
an online re-planning approach for grasping through clutter. The main challenge
is the long planning times this domain requires, which makes fast re-planning
and fluent execution difficult to realize. In order to address this, we propose
an easily parallelizable stochastic trajectory optimization based algorithm
that generates a sequence of optimal controls. We show that by running this
optimizer only for a small number of iterations, it is possible to perform real
time re-planning cycles to achieve reactive manipulation under clutter and
uncertainty.Comment: Published as a conference paper in IEEE Humanoids 201
'Behind Enemy Lines' Menzies, Evatt and Passports for Peking
This article focuses primarily on Australian government responses to the 1952 Peace Conference for Asia and the Pacific Regions. Because the conference was to be held in Peking, it was the subject of immense controversy: Chinese
communists were fighting Australian soldiers in Korea and Australian peace activists, most communist or 'fellow travellers', sought to travel behind the 'bamboo curtain'. In this context, the Menzies government's policies on passports were sharply silhouetted. Although this conference has been overlooked in the literature, we can infer from the trajectory of relevant Cold War historiography that Prime Minister Menzies would adopt restrictive, even draconian, policies.
This article argues otherwise. It suggests that it was that consistent champion of civil liberties, former deputy prime minister, attorney-general and secretary of the General Assembly of the United Nations and now, in 1952, Leader of the Opposition, Dr Evatt, who favoured more repressive action towards prospective delegates. In contrast, Menzies and his Cabinet were more lenient and shifted towards a harsher policy belatedly and reluctantly. This episode, therefore, challenges some comfortable assumptions about how the early Cold War was fought in Australia
Discussion of âclustering on dissimilarity Representations for detecting mislabelled Seismic signals at Nevado del Ruiz Volcanoâ by Mauricio Orozco-Alzate, and CĂ©sar GermĂĄn Castellanos-DomĂnguez
The authors are to be congratulated for a systematic investigationof the accurate and non subjective classifying approach in seismic research. The authors have conducted several clustering algorithms to the seismic event records from Volcanological and SeismologicalObservatory at Manizales. Their objective was to improve the grouping of seismic data (i.e., volcano-tectonic earthquakes, long-period earthquakes and icequakes) digitized at 100.16 Hz sampling frequency.Their study seems adding new approach to their previous work of Langer et al. (2006) who applied different classification techniques to seismic data
Applications of Cognitive Radio Networks
The term cognitive radio (CR), originally coined in the late 1990s, envisaged a radio that is aware of its operational environment so that it can dynamically and autonomously adjust its radio-operating parameters to accordingly adapt to the different situations. Cognition is achieved through the so-called cognitive cycle, consisting of the observation of the environment, the orientation and planning that leads to making appropriate decisions in accordance with specific operation goals, and finally, the execution of these decisions (e.g., access to the appropriate channel). Decisions can be reinforced by learning procedures based on the past observations and the corresponding results of prior actuations
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