7931157
A Heuristic Approach to Reconstruct Triangle Mesh from Unorganized Point Cloud
A heuristic algorithm was presented to reconstruct triangle mesh from unorganized point cloud, and a new error evaluation rule was presented to measure the reconstruction errors. The triangle meshes were reconstructed through two phases of mesh growing based on different strategies, where regions with high point density usually grow at the first phase and the remaining regions grow later. In each phase of mesh growing, the smoothest regions always grow firstly and then largely avoid errors emerging in sharp regions. The reformative best point selection method can improve the topology and geometry quality of the reconstructed meshes. The presented error estimation was inspired by the level of detail model and was also can be used in other region grow reconstruction approaches. Experiments show that the algorithm is efficient and effective.
35950271
Partition Triangle Meshes into Coarsely Quadrangular Segmentation
A feature captured approach was presented to automatically partition a triangle meshes into a coarsely quadrangular segmentation. The triangle meshes was firstly partitioned into a polygonal segmentation which was further split into triangular and quadrangular patches. After the convex and concave features were identified, the triangular patches were eliminated according to their topological relations to achieve the quadrangular segmentation. The optimization methods based on globally smooth parameterization and active contour model were also adopted to improve the qualities of quadrangular patches and their edges. The final segmentation consisted of pure-quadrangular patches with appropriate sizes according to the model's geometric characteristics, and the features of input model werewell captured.
42801293
Evaluation of an ultra-wide bandwidth wireless indoor non-line-of-sight channels
27110930
Solving the Group Priority Inversion Problem in a Timed Asynchronous System
Considers the priority inversion problem in an actively replicated system. Priority inversion was originally defined in the context of nonreplicated systems. Therefore, we first introduce the concept of group priority inversion, which extends the concept of (local) priority inversion to the context of a group of processors that perform an actively replicated processing. We then present the properties of a request scheduling protocol to enforce a total ordering for the processing of requests while avoiding group priority inversions. These properties have been implemented in a protocol that relies on a timed asynchronous system model equipped with a failure detector of the class /spl diams/S. The proposed solution allows us to replicate a critical server while ensuring that the processing of all the incoming requests is consistent (mechanisms for solving the atomic broadcast problem) and predictable (mechanisms for solving the group priority inversion problem). Thus, the described request scheduling protocol is a key component which can be used to develop fault-tolerant real-time applications in a timed asynchronous system.
45310315
Enterprise Modelling Based Services Orchestration
Aiming at the problems of system integration and cross-system interoperability, Service-oriented Architecture (SOA) provides a new integration method and system infrastructure. The key for SOA development and implementation is services encapsulating and orchestrating of applications through certain mechanism so as to operate a complex business. Current workflow technique, business process modelling notation (BPMN) and business process execution language (BPEL) have made very meaningful attempt in this field. But these process modelling technologies have semantics incompleteness when they describe processes in multi-platforms and multi-departments environment. Regarding service-oriented business process modelling technology as the kernel technology, this paper presents the concepts and expression method of process collaboration, proposes services orchestration solution based on process collaboration, specifies service models' expression method and service modelling process through case study, and points out the role of business process modelling in services orchestration.
13971731
Video segmentation based on graphical models
This paper proposes a unified framework for spatiotemporal segmentation of video sequences. A Bayesian network is presented to model the interactions among the motion vector field, the intensity segmentation field, and the video segmentation field. The notions of distance transformation and Markov random field are used to express spatiotemporal constraints. Given consecutive frames, an optimization method is proposed to maximize the conditional probability density of the three fields in an iterative way. Experimental results show that the approach is robust and generates spatiotemporally coherent segmentation results.
117805231
Hierarchical methods for three-dimensional surface reconstruction
Surface reconstruction from raw data such as volume data, implicit functions, and scattered data in three-dimensional space is very useful in medical imaging, scientific visualization, and geometric modeling. In this study, several surface reconstruction techniques are investigated. A new surface reconstruction technique and several interpolation schemes are introduced for processing the volume data. A new hierarchical scheme for extracting three-dimensional surfaces from volume data is presented. The hierarchical scheme is used to visualize different levels of surface detail allowing a user to explore different features of the surface at different scales. Estimated surface curvature is used as a smoothness condition, and the distance measurement between different levels of surfaces constructed is used as a stopping criterion. The volume pyramid used by the hierarchical scheme was built and tested by two different data structures: an octree and wavelet transforms. The hierarchical method using three-dimensional wavelet transforms is also useful in multiresolution surface analysis. An adaptive hierarchical method using an octree is implemented to increase the accuracy of the surface by adaptively subdividing regions of high curvature using an appropriate interpolation scheme without substantially increasing the number of polygons.
9142519
Utilizing field usage patterns for Java heap space optimization
This research studies the characteristics of field usage patterns in the SpecJVM98 benchmarks. It finds that multiple object instances of the same class often exhibit different field-usage patterns. Motivated by this observation, we designed a heap compression mechanism that classifies object instances at runtime based on their field-usage patterns and eliminates unused fields to save space. To achieve the maximum space savings while minimizing the space and time overhead, our design combines three interrelated techniques in a novel manner: runtime object instance classification, field virtualization, and bidirectional object layout. An experimental evaluation reveals that this mechanism can reduce the maximum heap occupancy of SpecJVM98 benchmarks by up to 18% and 14% on average while keeping the application execution overhead low.