Abstract:Stylized liquid animations are produced in this paper. The liquid simulator is mainly based onoctree-staggered grid. This paper uses the compact difference scheme which is often used in non-staggered grid toachieve fourth order accuracy. The compact scheme is modified suitable to adaptive octree-staggered grid. In stylized rendering procedure, a 2D texture mapping method is used to generate still images. Laplacian scheme smoothing in time axes is introduced to maintain temporal coherence in animation. This algorithm can reduce the stroke “twinkle” phenomenon among frames.

Abstract:This paper addresses the problem of spherical parameterization, i.e., mapping a given polygonal surface of genus-zero onto a unit sphere. There exist some methods to deal with the problem in literatures. In this paper, an improved algorithm is constructed for parameterization of genus-zero meshes and aim to obtain high-quality surfaces fitting with PHT-splines. This parameterization consists of minimizing discrete harmonic energy subject to spherical constraints and solving the constrained optimization by the Lagrange-Newton method. Several examples show that parametric surfaces of PHT-splines can be constructed adaptively and efficiently to fit given meshes associated with the parameterization results.

Abstract:Two algorithms for evaluation of regular quad-mesh interpolatory subdivision surfaces are proposed.Algorithms are designed based on the parametric m-ary decomposition and construction of matrix sequence. The weights of the control points on the initial mesh can be obtained, through direct computation of the basic function values by multiplying the finite matrix sequence corresponding to the decomposition number sequence. Algorithm-I is based on 2D subdivision masks while the other is based on tensor-product. Numerical experiments show that the algorithms are efficient with low storage cost.

Abstract:The paper proposes a smooth schedule algorithm to render terrain data out-of-core. The terrain data is organized as a quad-tree with Z-order filling curve, which preserves the data continuity and improved the schedule efficiency. A schedule strategy basing memory allocation is designed to support the stable frame rate terrain rendering. Controllable schedule area, instead of the view frustum culling, is applied to achieve the balance between the in-core memory requirements and scheduling time. A pre-estimated approach is adopted to smooth the data exchange. The algorithm achieves a smooth schedule and successfully avoides the slow or jerky phenomena, usually caused by inefficient and unsmooth schedule. By compared with traditional methods, the algorithm proposed is feasible and efficient in out-of-core terrain visualization.

Abstract:Diagrams are used for representing design concepts and constructing function structure in the stage of conceptual design. This paper considers sketches as the language of communication in cooperative conceptual design and presents a tool that enables distributed participants to cooperatively construct diagrams in the form of freehand sketches. The tool is designed and implemented as a multi-agent system, which contains a set of agents to fulfill the requirements, including sketch-based interaction, sketch recognition, communication and coordination. The operating strategies of these agents are also addressed, including communication between agents, sketch recognition algorithm, and semantic consistency maintenance. The proposed approach is implemented in cooperative flowchart drawing.

Abstract:Traditionally, synthesizing the animation of floral blossom is accomplished mostly manually and hence a time-consuming and laborious task. This paper proposes an interactive biology-based flower modeling and animating approach. It models the initial shape of the floral components including petal, pistil, stamen and pedicel,and two terminal status of floral blossom with a sketch-based interface. The subtle geometry of the whole flower is created according to the phyllotactic rules. Then, it extracts a set of growth parameters for describing the floral blossom, and builds a dynamic growth model to regulate the continuous morphing of floral components in the process of blossom. Finally, a sequence of naturally deforming flower models is generated with these parameters.The initial experimental results demonstrate that this approach can efficiently generate visually pleasing simulation of floral blossom, which is consistent with biological rules.

Abstract:In pervasive computing environment, applications available for end-users are abundant, distributed and heterogeneous. In order to share these applications, this paper presents a user-centric applications sharing model which called U-ASM. The basic concepts and structure of U-ASM are defined, which abstract the applications from service providers as well as end-users. The paper uses ontology to organize distributed applications as a logic unit with semantic relationships and utilizes virtualization technology to encapsulate applications. Finally the paper presents a prototype of the U-ASM which validates feasibility and validity of the model. The research result has been applied in R&D infrastructure and facility development of ministry of science and technology and has great flexibility and extensibility.

Abstract:The original organizational evolutionary algorithm (OEA) is often trapped in local optima when optimizing multimodal functions with high dimensions. In this paper, following an analysis of the main causes of the premature convergence, it proposes a novel algorithm, called the multipoint organizational evolutionary algorithm (mOEA). To discourage the premature convergence, a crossover strategy of multiple points is designed to achieve a better diversity of leader population. Inspired by the cognition and learning physics of social swarms, an improved annexing operator enables members in an organization to either partially climb around their leader or randomly mutate within the search range. The new annexing manipulation both enhances fitness values and preserves a good diversity of member population. Experiments on six complex optimization benchmark functions with 30 or 100 dimensions and very large numbers of local minima show that, comparing with the original OEA and CLPSO, mOEA effectively converges faster, results in better optima, is more robust.

Abstract:In this paper, a 3D polar-radius surface moment is proposed, and is used for 3D model retrieval. 3D polar-radius surface moments are new moment invariants based on 3D polar-radius moments including the invariance on shift, rotation and scale transforms. Compared to previous methods to compute such moments, the computational complexity for calculating 3D moments can be decreased considerably. With the help of these moment invariants, the 3D models are distinguished accurately.

Abstract:The interaction modality constrained to desktop PC between user and WFMS is one of the main factors obstructing business processes to be widely applied in pervasive computing environment. In addition, the increasingly complicated and flexible group activities have been a salient feature of current business processes.Traditional workflow management systems have difficulties in supporting such features. By extending and improving modeling method and executing mechanism of workflow management system, a group-supported system is designed and implemented, which has the ability of interacting with users in multiple modalities. This paper introduces the new modeling method for multifold group activities as well as the mechanism supporting interaction with multiple modalities. Then some outcomes and findings in the applications of the system are discussed.

Abstract:The deployment of symmetric NAT makes the communication between hosts in a peer-to-peer application very difficult, which needs many relay node to provide NAT traversal service. Traditional relay nodes are all server hosts lie in the edge of network. To reduce the duplicate traffic and excess router load caused by server relaying, a UDP switch based router enhanced NAT method is proposed in this paper, which can resolve the bottleneck of network bandwidth by enhance router function independently.

Abstract:In CSCW community, group awareness model and application are an important research field. Base on the foundation of the past research, this paper proposes a model that support hierarchical role based structure called RHAM (role based hierarchical group awareness model) to analyze awareness information, base on relevant of tasks, as well as relationship of organization structure between collaborators. In RHAM, a group cooperation environment (GCE) is constructed firstly, and then GCE is extended by group awareness content, awareness hierarchy, the task decomposition rules. The model divides the awareness information into four levels based on role-task decomposition graph and relationship of group structure. Finally, the implementation mechanism, application and some related questions in the future research are discussed.

Abstract:The environment changes of the each part of the cooperative region are the key contexts for location-based collaboration. It’s important for users in different parts to have a spatial-fair opportunity to use shared resources such as communication channels in location-based collaborative system. So the floor control policy must consider the spatial fairness. Firstly, a floor quad-tree is put forward to record the spatial distribution of historical floor assignment and then floor index is constructed to judge the spatial priority of users’ floor requests. Secondly, a spatial fairness based floor sorting algorithm is proposed to sort the floor requests. Finally, a spatial fairness based fuzzy floor control policy is presented and verified by simulation. The conclusion is that the policy can reduce the spatial unfairness of floor-assignment times and longest-waiting time.

Abstract:Particle Swarm Optimizers (PSOs) have been applied to solve Multi-Objective Optimization Problems (MOPs) for its successful applications in solving single objective optimization problems and are named as Multi-Objective PSOs (MOPSOs). However, MOPSOs are often trapped in local optima, cost more function evaluations and suffer from the curse of dimensionality. A cooperative coevolutionary and ε-dominance based MOPSO (CEPSO) is proposed to attack the above disadvantages. In CEPSO, the MOPs are decomposed according to their decision variables and are optimized by corresponding subswarms respectively. Uniform distribution mutation operator is adopted to avoid premature convergence. All subswarms share one archive based on ε-dominance, which is also used as leader set. Collaborators are selected randomly from archive and used to construct context vector in order to evaluate particles in subswarm. CEPSO is tested on several classical MOP benchmark functions and the simulation results show that CEPSO can escape from local optima, optimize high dimension problems and generate more Pareto solutions. Therefore, CEPSO is competitive in solving MOPs.

Abstract:WIMP-Based electronic teaching systems can not meet teachers’ requirements of natural and efficient interaction, especially continuous drawing and writing in geometry teaching. In this paper, an intelligent pen-based whiteboard system (IPW) for dynamic geometry visualization is designed and implemented. IPW can be used to add handwriting, outline and recognize geometry and manipulate interface elements with pen gestures. Through extended LIM0 algorithm dynamic geometric constraint solving and dynamic geometric visualization are supported. This paper discusses IPW’s framework and its key technologies, and gives application examples. Experimental results show that IPW has higher task completion efficiency and user satisfaction.