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191.
A digital signature with message recovery is a signature that the message itself (or partial of the message) is not required
to be transmitted together with the signature. It has the advantage of small data size of communication comparing with the
traditional digital signatures. In this paper, combining both advantages of the message recovery signatures and the certificateless
cryptography, we propose the first certificatelss signature scheme with message recovery. The remarkable feature of our scheme
is that it can achieve Girault’s Level-3 security while the conventional certificateless signature scheme only achieves Level-2
security. The security of the scheme is rigorously proved in the random oracle model based on the hardness of the k bilinear Diffie-Hellman inverse (k-BDHI) problem. 相似文献
192.
User selection is necessary for multiuser multiple-input multiple-output (MIMO) downlink systems with block diagonalization
(BD) due to the limited free spatial transmit dimensions. The pure user selection algorithms can be improved by performing
receive antenna selection (RAS) to increase sum rate. In this paper, a joint user and antenna selection algorithm, which performs
user selection for sum rate maximization in the first stage and then performs antenna selection in the second stage, is proposed.
The antenna selection process alternately drops one antenna with the poorest channel quality based on maximum determinant
ranking (MDR) from the users selected during the first stage and activates one antenna with the maximum norm of projected
channel from the remaining users. Simulation results show that the proposed algorithm significantly outperforms the algorithm
only performing user selection as well as the algorithm combining user selection with MDR receive antenna selection in terms
of sum rate. 相似文献
193.
Of different model-based methods in vision based human tracking, many state of the art works focus on the stochastic optimization
method to search in a very high dimensional space and try to find the optimal solution according to a proper likelihood function.
Seldom works perform a framework of interactive multiple models (IMM) to track a human for challenging problems, such as uncertainty
of motion styles, imprecise detection of feature points and ambiguity of joint location. This paper presents a two-layer filter
framework based on IMM to track human motion. First, a method of model based points location is proposed to detect key feature
points automatically and the filter in the first layer is performed to estimate the undetected points. Second, multiple models
of motion are learned by the prior motion data with ridge regression and the IMM algorithm is used to estimate the quaternion
vectors of joints rotation. Finally, experiments using real images sequences, simulation videos and 3D voxel data demonstrate
that this human tracking framework is efficient. 相似文献
194.
Maren L. Outwater Greg Spitz John Lobb Margaret Campbell Bhargava Sana Ram Pendyala William Woodford 《Transportation》2011,38(4):605-623
This research seeks to improve the understanding of the full range of determinants for mode choice behavior and to offer practical
solutions to practitioners on representing and distinguishing these characteristics in travel demand forecasting models. The
principal findings were that the representation of awareness of transit services is significantly different than the underlying
assumption of mode choice and forecasting models that there is perfect awareness and consideration of all modes. Furthermore,
inclusion of non-traditional transit attributes and attitudes can improve mode choice models and reduce bias constants. Additional
methods and analyses are necessary to bring these results into practice. The work is being conducted in two phases. This paper
documents the results of Phase I, which included data collection for one case study city (Salt Lake City), research and analysis
of non-traditional transit attributes in mode choice models, awareness of transit services, and recommendations for bringing
these analyses into practice. Phase II will include data collection for two additional case study cities (Chicago and Charlotte)
with minor modifications based on limitations identified in Phase I, additional analyses where Phase I results indicated a
need, and a demonstration of the research in practice for at least one case study city. 相似文献
195.
Nicole A. Costa Jeanette J. Jakobsen Reto Weber Monica Lundh Scott N. MacKinnon 《WMU Journal of Maritime Affairs》2018,17(4):521-542
The aim of this study was to assess proof of concept and usability of a maritime service website prototype in a full-mission ship bridge simulator through Swedish mariners’ experiences and perceptions. This test was part of the European Commission’s EfficienSea2 project for e-navigation. The prototype was intended as an aid to existing standard systems and methodologies for planning, executing and monitoring voyages. The study began with 5 days of simulator trials focused on today’s standard practices. This served as a baseline to compare to subsequent 4 days of simulator trials testing the prototype. For data collection, observations, video footage, interviews, and eye tracking were used. Data analysis included breaking apart the qualitative data to capture the perceptions of the participants, and a preliminary analysis of eye-tracking data as a complement. The results suggested that the prototype could be more suitable for a route planning stage, that the participants were familiar with similar existing solutions from other manufacturers, and that the contents of the tool would be most beneficial if integrated within the Electronic Chart Display and Information Systems (ECDIS). There is a pressing need for the novel solutions to be user needs-driven, integrated with the existing technologies, and standardized across the domain, and these processes must go hand-in-hand with accounting for all involved stakeholders, procedures, regulations, and training, as this will alter the course of shipping. 相似文献
196.
Matt Johnston Erica Bickford Tracey Holloway Chris Dresser Teresa M. Adams 《Transportation Research Part D: Transport and Environment》2012,17(6):457-465
We use a combination of petroleum–diesel models, datasets and tools along with biodiesel-specific corrections to create a roadway-level emissions inventory capable of evaluating spatial, temporal and scale aspects of fuel distribution options for the Midwestern US. Specifically, we compare the emissions of a year-round “low-blend” biodiesel implementation scenario, already under consideration in a variety of states, with a more strategic summer-only, interstate-only “high-blend” scenario. Our results indicate that spatial and seasonal distribution decisions do affect the overall emissions impacts of any biodiesel deployment, even those at low-blend levels. However, we also finds that changes in emissions due to biodiesel are considerably smaller than those anticipated from improvements to engine and control technologies. 相似文献
197.
The coastal zone is attractive for human settlement because it tends to be resource rich, providing a good location to generate incomes and livelihoods. Equally, however, it is a complex and powerful natural environment, which means that the coastal zone often becomes a focus of conflict with multiple users competing for limited space and resources. Understanding the causes of, and determining solutions to, the ensuing problems requires inputs from a range of analyses across sectors and disciplines. However, different disciplinary and sectoral approaches frequently use different investigative methods, language, and means of presenting results. This article presents a framework that has been developed in collaboration with Indian institutions over the past three years in an effort to address some of these fundamental problems of analysis and translation into policy action. Key components addressed by the framework are strengthening the capacity to practice, knowing how to proceed and how to find out what needs to be known using experience-based problem solving. 相似文献
198.
Radar target signals and chaff cloud jamming signals have different characters by the wavelet transform. The wavelet coefficients
of radar target signals are highly correlated with its near-and-near-scale wavelet coefficients, however the correlativity
between the wavelet coefficients of chaff cloud jamming signals and its near-and-near scale wavelet coefficients is less significant.
Based on the binary-base discrete wavelet transform and the correlation algorithm, the method of target entropy to estimate
standard variance of the jamming signals and each scale is proposed to ensure reasonable threshold, to suppress chaff cloud
signals and finally to reconstruct mixed signals by the improved spatially selective noise filtration (ISSNF) method. The
extensive simulation results show that the proposed method can availably suppress chaff cloud jamming and decontaminate target
echo. 相似文献
199.
Bevan Marten 《WMU Journal of Maritime Affairs》2011,10(1):45-61
This article discusses the enforcement of shipping standards, with a particular focus on Part XII of UNCLOS. Section 6 of
Part XII contains the only comprehensive set of vessel-related enforcement provisions in the Convention, but the Part’s scope
is limited to “the preservation and protection of the marine environment.” Therefore, not all shipping standards fall clearly
within Part XII’s ambit, including those centered on safety, security, and crewing considerations. The enforcement provisions
of Section 6 are favorable to flag states and their vessels, and Section 7 contains a number of safeguards for their benefit,
so it is in the interests of these parties to have coastal state enforcement governed by Part XII. However, the ability of
coastal states to establish and enforce shipping standards that apply within the territorial sea extends to more than just
environmental matters. The result is that different standards give rise to different enforcement powers, depending on the
maritime zone in which a vessel is located, even if those standards arise from the same international agreement. It is suggested
that to remedy these problems, UNCLOS would need to be amended in order to provide a comprehensive enforcement regime for
the enforcement of shipping standards. 相似文献
200.
The Sydney Olympics held in September 2000 provided an opportunity to monitor the planning of transport provision for the world's greatest sporting spectacular. As the single largest major event, the pressures on a city's transport system are enormous, as witnessed by the previous Games in Atlanta and Barcelona. This paper takes a value-chain approach to assess transport performance as a crucial element in the delivery of the Sydney Olympic Games. We begin with a brief overview of strategic value, highlighting some generic aspects of value chains followed by the transport delivery system that came to the fore as significant 'drivers' in the value chain. This is followed by a summary of the effectiveness of the buses, trains, taxis, roads and the airport. A more detailed look is provided of the private bus sector where the problems leading up the opening of the Games received a great deal of media attention. The paper concludes with two stories, one good, one not so good, about transport and the Olympic Games. 相似文献