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181.
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
182.
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
183.
在轨交环控负载配电中,智能型成套设备通过对智能化仪表、控制器的遥信、遥测、遥控和遥调,实现了环控设备就地控制、环控电控室控制、上级监控系统控制的三级控制。在各种智能型成套设备方案中,分散式可编程逻辑控制器(PLC)方案在保证可靠性、实时性、适应性、集中度的同时,做到了资源整合共享、缩小故障范围,减少设备投资,为环控设备的配电、控制提供了有力的保障。 相似文献
184.
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
185.
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
186.
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
187.
A novel method toward color image segmentation is proposed based on edge linking and region grouping. Firstly, the edges extracted
by the Canny detector are linked to form regions. Each of the end points of edges is connected by a direct line to the nearest
pixel on another edge segment within a sub-window. A new distance is defined based on the feature that the edge tends to preserve
its original direction. By sampling the lines to the image, the image is over-segmented to labeled regions. Secondly, the
labeled regions are grouped both locally and globally. A decision tree is constructed to decide the importance of properties
that affect the merging procedure. Finally, the result is refined by user’s selection of regions that compose the desired
object. Experiments show that the method can effectively segment the object and is much faster than the state-of-the-art color
image segmentation methods. 相似文献
188.
Democratic group signature (DGS) is a group-oriented primitive with great flexibilities, i.e., no group manager, anonymity,
and traceability. In a DGS scheme with (t, n)-threshold traceability, any subset of not less than t members can jointly reveal the identity of the signer while preserving security even in the presence of an active adversary
can corrupt up to t − 1 group members. This paper proposes an efficient DGS scheme. We use publicly verifiable secret sharing (PVSS) to distribute
the trapdoor via which the real signer is revealed. The computation cost and communication overhead of our DGS signatures
are greatly reduced, compared with the existing work. For example, the size of the resulting signature contains only 2n + 1 elements of Z
q
, except the PVSS output. 相似文献
189.
城市客运交通结构是关系城市交通系统发展方向的核心问题。从城市交通可持续发展角度出发建立了大城市客运交通结构优化的线性规划模型,其中决策变量为城市客运交通系统中各种交通方式的周转量。该模型的目标为最大化城市客运交通效率,该交通效率不是简单的各种交通方式客运周转量的函数,而是由各种交通方式的客运周转量和各种交通方式对城市客运交通效率贡献率共同决定。同时考虑客运交通结构优化过程中应满足的出行需求总量约束、可达性约束、占地约束、能耗约束、环境容量约束和各种交通方式发展规模约束等。该模型在实际应用中取得了良好的效果。 相似文献
190.