Skyline query is important in the circumstances that require the support of decision making. The existing work on skyline queries is based mainly on the assumption that the datasets are static. Querying skylines over moving objects, however, is also important and requires more attention. In this paper, we propose a framework, namely PRISMO, for processing predictive skyline queries over moving objects that not only contain spatio-temporal information, but also include non-spatial dimensions, such as other dynamic and static attributes. We present two schemes, RBBS (branch-and-bound skyline with rescanning and repacking) and TPBBS (time-parameterized branchand-bound skyline), each with two alternative methods, to handle predictive skyline computation. The basic TPBBS is further extended to TPBBSE (TPBBS with expansion) to enhance the performance of memory space consumption and CPU time. Our schemes are flexible and thus can process point, range, and subspace predictive skyline queries. Extensive experiments show that our proposed schemes can handle predictive skyline queries effectively, and that TPBBS significantly outperforms RBBS.

Service Oriented Architecture is currently regarded as the next step for software architectures and achieve great usage in web services. However, the traditional SOA uses request/response pattern and is not suit for loose coupling, asynchronous scene while Even-Driven Architecture works well. To support the effective execution of possibly distributed and completely decoupled and heterogeneous services, synchronously or asynchronously executed in an efficient manner, there is an urgent need to integrate EDA and SOA into the next generation of SOA. We propose a semantic publish/subscribe system called JTangPS to serve as the event platform for event based SOA to satisfy the new challenges.

We propose a novel iterative searching and refining prototype for tagged images. This prototype, named PivotBrowser, captures semantically similar tag sets in a structure called pivot. By constructing a pivot for a textual query, PivotBrowser first selects candidate images possibly relevant to the query. The tags contained in these candidate images are then selected in terms of their tag relevances to the pivot. The shortlisted tags are clustered and one of the tag clusters is used to select the results from the candidate images. Ranking of the images in each partition is based on their relevance to the tag cluster. With the guidance of the tag clusters presented, a user is able to perform searching and iterative query refinement.

In this paper, we propose an image semantic model based on the knowledge and criteria in the field of linguistics and taxonomy. Our work bridges the "semantic gap" by seamlessly exploiting the synergy of both visual feature processing and semantic relevance computation in a new way, and provides improved query efficiency and effectiveness for large general image databases. Our main contributions are as follows: we design novel data structures, namely, a lexical hierarchy, an image-semantic hierarchy, and a number of atomic semantic domains, to capture the semantics and the features of the database, and to provide the indexing scheme. We present a novel image query algorithm based on the proposed structures. In addition, we propose a novel term expansion mechanism to improve the lexical processing. Our extensive experiments indicate that our proposed techniques are effective in achieving high runtime performance with improved retrieval accuracy. The experiments also show that the proposed method has good scalability.

In this paper, we present an optimization framework for querying XML data by caching frequent query patterns. In this framework, frequent query patterns are mined online from user queries, and these query results are cached for future use. The mining process of frequent query patterns is launched automatically when user queries meet predefined requirements. To deal with queries that are similar to but not exactly same as the cached ones, a novel technique named query rewriting is adopted. This technique is able to handle four kinds of similar queries namely exact matching, exact containment, semantic matching and semantic containment. A cache replacement scheme that utilizes both the query pattern support and query pattern accessing time is employed to perform a fine-grained region purging. Experiments are carried out on the XMARK datasets. The results show that the proposed methods are both effective and efficient in improving the performance of XML queries.

Mobile devices quickly become popular tools in collaborative design for their portability and supporting of graphics user interface. However, their limited resources may result in the complexity of rendering 3D products. Non-photorealistic rendering is extremely suitable for mobile devices since they efficiently save computational power and convey visual information. In this paper, a new approach is proposed to deal with mobile collaboration based on non-photorealistic rendering. In contrast to traditional methods, our method describes the user's design intent in an XML-based model, which is customizable and improves the collaboration between mobile users.

Over the last decade, the architectures and technologies used for enterprise application integration have been improved, and many companies have proposed varied solutions for integration. But these traditional approaches have some disadvantages such as high cost, poor flexibility and vendor lock-in. And now, the service oriented architecture, advanced in loose-couple, low cost and high integration ability, is thought to be the most advisable approach for business integration. In this paper, we introduce an SOA based enterprise application integration platform named JTang Synergy. JTang Synergy is composed of a basic integration platform, a supported platform, administration tools and development tools. As the core of JTang Synergy, the basic integration platform is implemented according to Java Business Integration which makes JTang Synergy more flexible and vendor-neutral. And we employed an event-based enterprise service bus to realize integration. The supported framework and the tools ease JTang Synergy to develop and integrate services. And a scenario is introduced to illustrate the integration process using JTang Synergy.

Internet-based manufacturing can greatly improve the efficiency of collaboration between enterprises and exploit more of the resource for legitimate use, so it is valuable for both the improvement of new product development and reduction of cost. With the augment of the resources and services, it's become difficult to find what a user wants using a key word based method. Semantic Web is a useful tool for resource and service sharing. We present a framework for manufacturing resource and service discovery, and give a method to ranking the search results semantically.

Hybrid P2P technique recently has become more and more popular for collaborative systems. However, reliability is issue of major importance in the server end of these systems. TMR technique for Collaborative System (CS-TMR) is presented in this paper to improve the server reliability. This software schema incorporates three homogeneous microcomputers and provides the fault-tolerant function through package interfaces to server applications. As it is COS-based, the method is more general-purpose, and programmers need not pay too much attention to the fault tolerance technology in detail. This method helps the collaborative server work in normal and degraded (duple or even single modular) modes, and can tolerate transient or permanent faults. Meanwhile, due to the importance of the server in hybrid P2P server, server application upgrade is impossible without server stop. A novel seamless software upgrade method is brought forward through the intelligent state-transition-control in CS-TMR package to reduce the cost of software upgrade.

The responsibility of resource server is to store and manage the reusable and product-specific assets produced in the process of software development applying software product line principals. Separately designed for each specific resource type, classical resource server could not satisfy the demands for mass storage of various resource types in collaborative development environment. Interception design pattern is introduced as a novel means to implement resource server. Interceptors with specific functionalities are developed and configured for various resource types in domain to provide a uniform framework to deal with distinct types of resource, including customized resource type. The description of the resource handling process using Pi calculus demonstrates the validity of the approach.

To effectively integrate product information spanning various stages throughout the whole product life cycle, and facilitate seamless sharing and interoperability at knowledge level in heterogeneous collaborative environment, a framework of integrated product modeling based on multiple ontologies is presented. This framework is composed of master model and domain models with the development of a shared basic ontology and domain-specific ontologies. Both the ontologies enable product knowledge acquisition and management. The layered master model contains semantic-enriched core and shared information and supports product and process integration. By extracting from master model and knowledge-based reusing from others in different contexts, the domain models are established with well-defined meaning, which permits each discipline to work on its own perspective while ensuring co-ordination and consistency at knowledge level in multidisciplinary collaborative product development.

With the rapidly increasing popularity of XML as a data format, there is a large demand for efficient XML structural matching techniques. Normally, data in XML are stored in a tree-like structure where nodes (with data) are located using the path relations in the tree. This paper proposes a coding policy named path code to accelerate an important category of structure matching in XML, namely the Parent-Child paths. A Parent-Child path is the path expression that contains only parent-child relationships. The proposed path code employs a partial prefix Path of XML elements using a special compression technique. Based on the path code, we present a Boosting algorithm, which has low-linear time complexity and little I/O cost, to match Parent-Child paths. In addition, we propose two heuristic policies to optimize the Boosting algorithm further by reducing the memory consumption. Our experiments show that the Boosting algorithm considerably outperforms previous algorithms in run-time Parent-Child path matching.

Heterogeneity and uncertainty are two main characteristics of pervasive computing environment and CSCW. CSCW can be viewed as a special case of pervasive computing. Middleware is a good approach to accommodate heterogeneous and dynamically changing devices for CSCW and pervasive computing. In this paper, we propose the service discovery method adopted in our DOM-based middleware architecture, which aims to support as many types of pervasive environments as possible. Services in our middleware architecture are dynamically structured and can be adapted to the environments' changes or users' requirements. Our middleware architecture can also be used to support service collaboration in CSCW.

We designed and implemented MSFSS, a scalable and flexible distributed file system for storage and retrieval of mass small files. MSFSS is a platform built upon the existing commodity file systems. It automatically stores files onto the best-fit commodity file systems according their access patterns. To avoid central bottleneck, it optimizes metadata size, separates metadata operations from file data transfer, and implements batch metadata operations. The system provides data migration, hot file caching, and replication, which are essential for large scale, reliable storage systems. It has successfully been deployed as storage system for our Web application which has about 50 TB of small files. Experimental results show that MSFSS provides high scalability and throughput in file operation services.

Virtual manufacturing (VM) has been proved in different industrial contexts as an effective technology to ensure competitivity and increase profit margins. This paper presents such a system named MEWS, short for module-based extensible integrated VM system. The system now contains 7 modules and owns good extensibility. One of the most important modules is assembling module. It has significant impact on the performance of the system. The adoption of hierarchical assembly model with discrete patches brings many benefits for the whole system as well as the assembling module itself. And the hybrid assembly sequence planning based on subassembly identification with human-interaction expands the planner's scope of application and enhances its robustness, while restricts human-interaction in hierarchical layers of the assembly model.

In this paper, we propose a new algorithm called Orthogonal Neighborhood Preserving Embedding (ONPE) for face recognition. ONPE can preserve local geometry information and is based on the local linearity assumption that each data point and its k nearest neighbors lie on a linear manifold locally embedded in the image space. ONPE is based on Neighborhood Preserving Embedding (NPE), but overcomes the metric distortion problem of NPE, while metric distortion usually leads to performance degradation. Besides, we propose a classification method (ONPC) based on the ONPE, which use local label propagation method in the reduced space for face recognition. ONPC is based on the natural assumption that the local neighborhood information is also preserved in reduced space, and the label of a data point can be obtained in the reduced space by the labels of its neighbors. Experimental results on two face databases demonstrate the effectiveness of our proposed method.

Database encryption is a crucial technique in the security mechanisms of database. It is widely recognized as one of the key issues of data security. Current techniques of sharing the keys and the encrypted data for databases are neither convenient nor flexible in the real applications. Inspired by the PGP technique, we propose a novel database encryption scheme for enhanced data sharing inside a database, while preserving data privacy. It is characterized by both the fast speed of the conventional encryption and the convenience of key distribution of public key encryption. It also provides secured storage for security related data and effective key management, which enables the encrypted data to be shared conveniently. The scheme has been implemented and successfully applied on Oscar, a commercial DBMS developed by us

With the development of advance manufacture applications, enterprise must interact with their suppliers and customers to share more product data information. Consequently, copyright and integrity protection over product data is becoming an urgent requirement. Product data information consists of two parts: product structure and part content, besides protecting the three-dimensional (3D) model of part by watermarking, we also need to protect product structure information, which describes the relations among product parts and can be represented as a tree. In this paper, based on the 3D polygonal meshes watermark technology, the structure/semi-structure data watermark technologies and the idea of Fractal, we propose a novel watermark scheme for tree-structure product data with the value lying both in product structure and in part node content, which gives a more comprehensive and resilient right protection for both part node content and product structure. Moreover it is particularly effective when resisting invertibility attacks

This paper analyses the operational coordination mechanisms between the core enterprise and the partners within a supply chain having private local information. For a make to order production setting, a hybrid model of synergic production scheme based on negotiation is proposed. After analyzing the characteristic of synergic production process, this paper establishes the hierarchy of synergic production process monitoring. In the production process monitoring, four monitoring modes are defined according to the significance of the items in the whole product. A Web-based synergic production management system for supply chain has been implemented with programming in ASP and Ms SQL server. The application shows that the approach proposed in this paper is applicable to practical production in supply chain

The traditional OBSM method in spacecraft and other real time embedded system is to re-compile the whole system after source code modification, and then reboot the target machine with the new version software. This hurts the availability of the system. Most of the new methods are based software or hardware redundancy. To reduce the cost and make the OBSM more conveniently, we classify OBSM, and patch the target system with different method according to different OBSM type, so the new solution can reduce the cost

Physical database design is a key phase in devising and deploying a database system to improve overall system performance, and automatic physical database design becomes an important value-added feature in a database system to decrease the TCO (total cost of ownership). A GAPDD (general automatic physical database design) framework, with two phases, the workload mining phase and the design advising phase, is provided to support automatic physical database design for relational database systems. Three collaborative agents, the workload mining agent (WMA), the feature generation agent (FGA), and the optimal search agent (OSA) work together in GAPDD. The feature generation procedure in FGA is further studied, and a reasoner based on description logics (DL) is offered to reason useful features. An index advisor for OSCAR relational engine is prototyped, and experiment results show its feasibility and efficiency

This paper proposes a local registration approach of medical images with niche genetic algorithm. In our approach, the deformation function is obtained by interpolating discrete point-landmarks using radial basis function with compact support. The locality of deformation function can be conveniently controlled by distributing the point-landmarks into the desired regions, which especially allows us to deal with local changes in medical images. With niche genetic algorithm, the action scope of each point-landmark is optimized to minimize the sum of squared difference of intensity between two images. Experimental results show that the performance of our image registration approach is very promising in controlling the locality of deformation function

This paper presents a new reverse engineering method for creating 3D mesh models, which approximate an unorganized noisy point set without orientation information. The new method computes sample points by the extended moving least squares method in adaptive octree cell. The octree subdivision is decided by weighted covariance matrix. Then the points are connected by intersections of supported spheres. Further, the triangular meshes are refined to remove non-manifold parts and holes. The new algorithm allows us to construct mesh models from very large point set quickly

This paper presents a framework for design of online courses and collaborative learning based on Web technologies. It provides the following features: construction of structured learning materials in a distributed environment; personalization of course contents in the run-time that adapts to the progress of individual students; it can supply relevant Web resources to the students by analyzing the learning history dynamically; students in a group could exchange their learning experiences and discover relevant knowledge via the communication channels provided by the framework. The proposed techniques could be deployed to a variety of online computer-assisted modules to improve the effectiveness of Web-based e-learning

XML is rapidly emerging as a standard for information storage, representation and exchange on the Web. How to rapidly search and query XML documents efficiently has received many attentions in resent research. However, current querying schemes of XML documents typically involve in both node content and tree structural information, which may limit efficiency when facing the application that the tree structural information is more complicated than the tree node itself. In this paper, we propose the node relationships joins algorithms that utilize available indexes mainly on tree structural information. The relationships join algorithms work perfectly especially for searching paths that are very long or whose lengths are unknown. Experimental results from our prototype system implementation highlight the correctness and efficiency of our solution

Collaborative design and application integration emphasize the demand for database security. Database encryption is widely adopted to ensure data privacy, which can prevent attacks from both outside intruders and inside malicious users. Current researches on this area are mainly focusing on encryption algorithms, key management and encryption efficiency. However, data sharing nature of database system is usually neglected. In this paper, we propose an access control model, 3S-RBAC, which enables data sharing while guaranteeing privacy. The model has many features: the novel concept of strong permission and weak permission; the hierarchy of database objects and keys; the permission and key inheritance; the binding of keys and permissions. Implementation in OSCAR Secure DBMS shows that the model is flexible, secure, practical, and can be integrated easily into existing enterprise applications

The access control architecture using state-transfer-based dynamic policy is proposed to make access control more flexible and dynamic. This architecture can dynamically change the policy according to a state-transfer composed of a previous state and a current state. It can indicate the tendency of the system by using both previous and current information in order to decide a more appropriate policy to the current system and future condition. And there are two steps in this dynamic policy method, one is deciding a partial-state and the other one is deciding a state, two dynamic policy decision layers are included into this architecture in order to manage these two steps.

This paper presents a novel architecture for collaborative multi-agent functional modeling in design on the semantic Web. The proposed architecture is composed of two visiting levels, i.e., local level and global level. The local level is an ontology-based functional modeling framework, which uses Web ontology language (OWL) to build a domain-specific local functional design ontology repository. Using this local ontology repository, the requests coming from the functional design agent can be parsed and performed effectively. The global level is a distributed multi-agent collaborative virtual environment, in which, OWL is used as a content language within the standard FIPA agent communication language (FIPA ACL) messages for describing ontologies, enabling diverse functional design ontologies between different agents to be communicated freely. The proposed architecture facilitates the exchange between diverse knowledge representation schemes in different functional modeling environments, and supports computer supported cooperative work (CSCW) between multiple functional design agents

Several existing research protocols have already studied long running transactions within a formal context and many of them seemed to use concepts which are not suitable. However, there still exists a great challenge to perform transactions in the loosely coupled environment. In this paper, we present formal model for compositional protocol with the asynchronous /spl pi/-calculus with compensation and exception handling. We study the practice of /spl pi//sub RBT/-calculus, by discussing few paradigmatic examples, its theory, by defining semantics and providing a correct encoding of /spl pi//sub RBT/-calculus into asynchronous /spl pi/-calculus. /spl pi//sub RBT/-calculus is a business process modeling protocol and a distinctive feature of the language is its support for compensation. Compensation is an action taken to recover from error or cope with a change of plan, especially when rollback of a process is not possible. We also propose a process-oriented transactional business coordination model with hierarchical structure. It allows dependencies across hierarchies and supports various transactional behaviors of different services. Based on this model, a novel failure recovery algorithm is presented. It can ensure semantic atomicity for long running Web services composition. Analysis shows it can effectively reduce compensation sphere and thus decrease costs.

This work presents agent-oriented and service-oriented environment, which combines the concept of services and agents to build distributed system. Customers may find services that help complete their tasks. Services are wrapped by service interface agents. It is mainly described here how agents locate specific service interface agent by submitting requests to the service server with descriptions of required services in the network. We also discuss the intermediate source role of /spl pi/-calculus technology in the co-operation of P2P process systems to get services within intra-organizational and inter-organizational connectivity. Our translation replaces P2P communication shared with different local and global organizations; we prove that this preserves and reflects process meets essential requirements for inter-organizational processes system based on an Internet service daemon. This paper mainly describes the approaches, how agents locate specific product service interface agent by submitting requests to the different organizations product service server with descriptions of required product services in the inter-connected organizations.

An efficient method for simulating cartoon style rain in 3D environment is proposed here. By taking advantage of the parallelism and programmability of GPUs (graphic processing units), real-time interaction can be achieved. Splashing of raindrop is simulated using collision detection, series of stylized textures and rotations of point sprites. To simulate wind-driven raining effect, the motion of particles can be freely controlled based on Newtonian dynamics. We can also control the size of raindrops dynamically by using different textures or changing the size of point sprites. Many experiments have been done in 3D scenes with different complexity and GPU-based stylized rendering. The experimental results demonstrated the efficiency of our method for real-time rain simulation in cartoon style with complex geometries of 3D scenes.

This paper presents a new method for rapidly generating accurate patient-specific lumbar spine volume mesh for finite element analysis. First, initial isosurface of the vertebral body is extracted from CT volume data. Then, a series of non-parallel "best cross-section planes" are placed semi-automatic ally according to the morphologic characteristic of surface model, forming a "non-regular piecewise subspace". This subspace and the embedded surface model are transformed to a "regular subspace" covered by a regular structure grid. Based on the information from the 2D contours of warped surface model, the "structure grid contours" are generated, from which a surface mesh of high quality is generated. At the same time, these grid nodes inside of the surface mesh are recorded as insertion points, and the tetrahedral volume mesh is created quickly by a boundary constrained Delaunay triangulation procedure in the "regular subspace". Finally a two-step reverse transform procedure is employed to recover the shape feature of the lumbar volume mesh in the original three-dimensional space, achieving a smooth change of element size transition.

With the rapid development of CSCW techniques, CSCW system security has been of much attention. Its major challenge comes from malicious attacks, which cannot be handled by traditional security mechanisms, such as authorization, access control, encryption, etc. Although there existed some intrusion detection systems, current researches on intrusion detection are still insufficient in accuracy and efficiency for two reasons: firstly, most of them implement malicious transaction detection only by matching samples with predefined patterns; secondly, most current researches mainly resort to semantic analyzing or even only manual interventions to judge the malicious attacks. Inspired by the replication technique, we propose and implement a novel logical replication-based intrusion detection solution for CSCW system in this paper. It provides an additional layer of defense against application attacks, especially program attacks. The approach entitles the system to detect malicious intrusions efficiently at low false positive rate.

Nowadays, networked manufacturing system based on ASP (application service provider) has become one of the hotspots of research and application. How to manage large amount of ASP services, and how to provide better service quality, has become very important. The paper mainly studies the ASP service management technologies. We present the concept of service lifecycle management (SLM), defines ASP service, and set up a state model for service lifecycle. Then, we give several key technologies' solutions for implementation of service management. Finally the application of these technologies in a real networked manufacturing system is introduced.

CAD systems increasingly require distributed collaborative design capabilities to meet the designers at different geographical locations to co-develop parts. It involves transmitting the CAD models back and forth among the systems in a distributed design environment. However, it is very difficult to apply because the CAD models are always very complex and the current network bandwidth is limited. In this paper, some important work about the compression and transmission of CAD models through the network is elaborated. Meanwhile, because a feature-based model always contains many extruded and revolved features, then we propose a new approach to transmission of feature-based models to deal with these extruded and revolved features. This approach can effectively cut down the transmission delay of the feature-based models, especially when the model contains many extruded and revolved features.

We present an efficient method for simulation of raining phenomenon in real time by taking advantage of the parallelism and programmability of GPU (graphic processing unit). Our implementation of the method is based on particle systems and collision detection. Splashing of raindrop is simulated using a series of stylized textures and rotations of point sprites. Taking into account human perception in raining phenomenon of real world, the effects such as light influence, depth of field, motion blur, have been applied. The test results show that our method is efficient and is feasible to solve the problem of 3D raining simulation in real time for more general environment with complex geometry.

Load balancing is a key technique in parallel computer supported collaborative work (CSCW) systems, parallel database system and P2P system for instance, to boost performance and improve scalability. In order to reduce total cost of ownership (TCO), adaptive/self-tuning administration techniques are gradually and extensively expected in the cyberspace. In parallel database systems, adaptive load balancing techniques are proposed to face the change in data storage patterns and access patterns in a dynamic real environment. The techniques utilized in both shared-nothing and shared-disk parallel database systems are discussed, and a general flexible framework based on collaborative agents is studied to support these techniques in both architectures. The framework supports two kinds of load balancing - one is passively executing query statements balancedly, and the other one is proactively adjusting data placement and task execution scheme, by means of data and task migration, whenever load unbalance is detected. Three categories of agents, scheduling agents, monitoring agents and task agents, are identified in the framework. The collaboration protocols and scheduling algorithms to support adaptive load balancing are described. The framework also applies to other parallel systems such as P2P systems and shared file processing systems due to their underlying commonness.

As the tooth root has similar bone density with the jaw where it is embedded, its complete boundaries are either missing or at low contrast in the computed tomography (CT) volume data. This paper proposes a consistent semi-automatic landmarks selection and replacing procedure, then uses thin-plate splines to deform a 3D geometric prior model to match the 3D patient CT volume, producing a "best-fit" patient specific polygonal mesh of the whole tooth.

To flexibly integrate various systems at different stages and improve the openness and reusability of information in remote collaborative product development, a framework of integrated product modeling based on Web services is presented. The integrated model consists of a master model and application models that combine static and dynamic information supporting whole product lifecycle. The master model contains the core and shared information. The application model relating to specific manufacture domain is built up by extracting the master model and complementing domain information. The flexible integration of heterogeneous systems is ensured by the use of Web services. The openness and expansibility are preserved by combining STEP and XML for information representation and exchange. The high reusability of product information is achieved by using a service-oriented multi-granularity schema. The information consistency among the master model and application models is maintained through a coordinated-protocol for rapidly acquiring alteration and reacting to it.

This paper presents an adaptive-weighted hidden Markov models (AWHMM) method for classification of 3D models into a set of pre-determinated model classes. Two new features are proposed to capture model surface orientation information. In the method, each model class is represented by four HMMs corresponding to four type features. During the training process, for each type of feature, the feature statistics of each model class and the spatial dynamics are learned by an HMM. During the classification process, characteristics of the test model are analyzed by the HMMs corresponding to each model class. The likelihood scores provided by the HMMs are calculated, and the highest weighted sum score provides the class identification of the test model. Furthermore, with unsupervised learning, each HMM and type weight are adapted with test models, which results in better modeling over time. Based on experiments, the proposed algorithm achieves much better performance than a baseline method and better performance than HMMs using only two features with fixed weights method.

This paper presents a novel algorithm for optimal packing problem by combining ant colony algorithm with BLF (bottom-left-fill) heuristic approach. The proposed algorithm not only automatically looks for the best sequence of the polygons and each polygon's optimum rotation by ant colony algorithm but also implements the exact layout with the BLF heuristic algorithm. Moreover, the algorithm supports the parallel computation and facilitates quick convergence to the optimal solution. The experimental results show the effectiveness of our algorithm comparing with the other methods.

In this paper, we propose a generic framework for multidisciplinary design optimization application, which incorporates several existing technologies such as workflow, agent, adapter, Web and XML workflow is used to allow the designer to construct complex branching and iterative MDO problem formulations and automate the design process execution. Agent is employed to manage and coordinate the operations on system resources, and more significantly perform the dynamic load balancing among a cluster of computers. Adapter is integrated to encapsulate commercial or noncommercial engineering tools to provide the designer with uniform interfaces. Web enables the geographically distributed experts to solve a multi-disciplinary problem cooperatively. XML is used to exchange data between adapters and applications. A Java-based prototype system implementation of the proposed MDO framework is presented.

Most of current collaborative feature modeling systems use the token-passing method as its collaborative strategy that makes the collaborative design between multi-clients inflexible and inefficient. Based on the analysis of feature operation in collaborative environment, we propose a new method to solve the concurrency conflicts, an enhanced naming mechanism for collaborative feature modeling to preserve the design intensions, and a process for non-locked multi-client collaborative design. The algorithms have been implemented in a prototype system integrating C++, Java3D and VML, CORBA technologies. Flexibility and efficiency in collaborative feature modeling environment have been achieved in our system.

This paper introduces DXEC, a database, XML and email enabled framework for better collaborative work. The framework use emails as the main collaboration medium, which are mainly generated automatically by OA applications and groupware systems. But instead of using them naively, each email in the system are wrapped in a XML envelop, which provides superior searching and filtering ability. Emails are stored in a XML enable database, and a XML filter engine is used to filter the incoming messages and disseminate them to relevant audiences. User profile in XPath, which can be specified by hand and refined through feedbacks, are used by the filter engine to ensure everyone received only interested messages. In this paper, we present the architecture of DXEC and introduce major components and important algorithms. We also demonstrate its use in software development process.

Networked manufacturing oriented cooperative CAPP system has become one of the hotspots of research and application. The paper mainly studies how to realize cooperative planning among heterogeneous CAPP systems in a networked manufacturing oriented environment. We put forward an idea for cooperative process planning. Then, we study some key technologies of it, including cooperative control command management technology and shared data processing. Finally an example of the networked manufacturing oriented cooperative CAPP system is introduced.

Currently available workflow management systems lack abilities for supporting interorganizational processes. In this paper, we present an approach to model interorganizational business processes based on the pi-calculus technique. This approach provides a formal foundation for processes with interorganizational interaction structures, appropriate for modeling distributed cooperative workflow systems.

Project management for virtual enterprise is a challenging task, current project system cannot support it very well because of the gap between enterprises. After analyzing the characteristics of virtual enterprise, the project domain was defined for supporting the virtual enterprise project management system. Then we discuss the information sharing mechanism between domains based on public, protected and primate library, and present a system architecture based on grid service. Experiments show that the proposed approach can be used in distributed project management environment, such as networked manufacture system.

When people navigate through virtual environments, they often manually control the camera, which may result in dizzy camera motions. In this paper, we introduce a new algorithm for camera planning in virtual environments, which will complete path planning, trajectory planning and orientation planning of virtual camera for the user with desired aesthetic qualities, while the user simply specifies the goal position. The path planning part of the algorithm is based on octree representation of the scene, associating with some ideas from visibility graph. It is more efficient and the resulting path is suitable for camera motion. We also describe an innovative approach for path smoothing and camera speed control in sharp turns, which strengthens the aesthetic effect with little overhead.

The CAD model simplification technology has been paid more and more attentions for the requirement of seamless integration of CAD/CAE/CAM. This paper presents a new approach for feature suppressing of Brep models using local error evaluation. The improvement is that several features can synchronously be suppressed, and time overhead will be reduced at initial step without recognizing among most of them.

The researchers and developers of DM system always ignore the fact that the development of complicated product is composed of several phases, each of which has its own management demands to documents. In this paper, we present a collaborative DM (document management) system to manage heterogeneous, distributed data of complicated products in the large size enterprises. A concept of library was introduced as the basic logic unit for storage and management of document data in accordance with phase. The difference of operations permitted in each library promised distinct management demands of specific phase. Typically, a product was divided into three libraries: a design library, a controlled library and a product library. Automatic document transfer between libraries was implemented in the charge of workflow. According to the concept of library, there could be one-to-one correspondence between each product and an independent database. In addition, each library operated with an individual, distributed file server for high throughput.

The increasing complexity of DBMSs and their workloads has made it a difficult and time-consuming task to manage their performance manually. Autonomic computing has emerged as a promising approach to deal with this complexity by making DBMSs self-managed. Automatic statistics management, as an important part of autonomic computing, is especially necessary in decision-support systems. In this paper, we introduce a novel technique for automatic statistics management called Self-Learning Histograms (SLH), which can adapt to workload and data distribution changes by automatically building and maintaining itself using query feedback information. Query feedback is encoded as deducible rules and the histogram can be viewed as a set of these rules. Through deducing among rules, more accurate statistics can be inferred and damages to results of former tunings are avoided. Selectivity estimation based on validity of rules greatly lowered estimation errors. Extensive experiments showed the effectiveness of SLH.

An architectural solution to reducing energy consumption of flash-memory storage system is to take advantage of a multi-bank architecture instead of a single-bank one. Thus, allowing unused banks to be placed into low-power operating modes can help reduce energy. In this paper, an adaptive energy-aware bank assignment policy is proposed to cluster data with temporal affinity into the same bank, increasing the number of banks put into low-power modes. Then we propose an energy-aware garbage collection policy, which could keep banks in idle conditions for long durations of time to compensate for resynchronization penalties. Experiments over the prototype show the effectiveness of these policies and indicate that large energy savings can be achieved with low overhead.

Silhouettes play a critical role in non-photorealistic rendering. The effect of the NPR greatly depends on the silhouette performance. And it is also a key technology for real-time NPR applications. This paper introduces the most popular and latest techniques in silhouette detection. We classify and analyze them, and discuss them with the problem of visibility determination. After analyze the advantage and disadvantage of them, the working context of them is also concluded.

In this paper we make an analysis of the product data integration problem and propose an ontology-based framework to facilitate the product data integration among enterprise information sources. Advantages of the framework are analyzed in detail, and an example described in DAML+OIL is given. We also make a comparison with EXPRESS modeling language.

Proxy signature is the solution to delegation of signing capabilities in electronic world. Proxy signatures are signature schemes that an original signer delegates his signing capability to a proxy signer, and the proxy signer creates signatures on behalf of the original signer. To avoid the misuse of proxy signatures, the original signer hopes that he can restrict the signing capability delegated to the proxy signers. In this paper, a designated-receiver proxy signature scheme is proposed. In this scheme, an original signer nominates a person as signature receiver when he delegates his signing capability to a proxy signer, and the proxy signer can generate valid proxy signature on behalf of the original signer which none but the nominated receiver can verify and accept, thus the misuse of proxy signature is avoided. The security of the proposed signature scheme is analyzed. The scheme will be applied in e/spl I.bar/commerce and other fields.

Based on the comparison and analysis to automated assemble planning and virtual assembly planning, a new assembly planning method named Intelligent Virtual Assembly Planning (IVAP) is proposed in this paper. After the main idea of IVAP is introduced, the architecture of the IVAP system, and the structure and functions of the main parts are discussed in detail. Then the paper focuses on the Integrated Assembly Model (IAM), which is the kernel part of the IVAP system and is used to represent different types of assembly knowledge and data. At last this paper presents the strategy of Multi-Level Intelligent Assembly Planning that is based on IAM.

Geometric constraint solving is a rapidly developing field, with applications in areas such as kinematics, molecular modeling, surveying, and geometric theorem proving. This paper has incorporated conic arcs into a geometric constraint solver and describes how to construct conic blending arcs from constraints using a rational parametric representation - rational quadratic Bezier which combines the separate cases of blending edges. There are some possible constraints: traverse a fixed point, or tangency to or distance from a line. Here a uniform rational Bezier representation has been developed first, then the paper presents two methods to solve tangency to or distance from a line.

In this paper, a model and algorithm of optimum layout is proposed for blank layout of single pattern on single rectangular sheet. The approach arranges the cutting patterns on rectangular sheet in the typical style of Double Opposite Layout (DOL). The remains of the sheet, which has been left in one direction after arranging patterns, called as "Step Leavings" (SL) is considered while the optimum layout is discussed We make full use of material of the sheet, including the A in x-direction and y-direction, and set up a reasonable mathematical model for the two-dimensional optimum layout. A corresponding algorithm is also provided to work out the optimum layout quickly and automatically. In this way, we can get the best layout scheme to arrange the maximum shapes on the sheet.

Access control, which is one of the most important aspects of security services, is becoming increasingly an important challenge in workflow management systems. However, the traditional models of access control, such as the role-based access control (RBAC), are static models without recognition of the dynamic environments in which the workflows are rooted. These context-independent models rarely can meet the requirements that the highly dynamic environments raise. In this paper, we regard authorization as a dynamic process instead of the traditional static view and take two contextual factors into account: (1) the state of related authorization processes; and (2) the state of related process instances. Then, we propose a Petri-net-based model as a practical solution to the context-sensitive access control on this basis.

One of the key technologies for distributed integrated manufacturing systems is to realize automatic transmission and conversion of product data among distributed and heterogeneous systems like CAD, CAPP, CAM, CAE, etc. This paper presents an Internet-based framework of product data exchange and the architecture of the framework, which uses Internet/CORBA as the communication platform and XML as product data exchange language. This framework within which, conversion of other data formats to XML format is implemented by software agents, supports exchange of structured and non-structured product data.

Three-dimensional geometric constraint solving is a rapidly developing field, with applications in areas such as kinematics, molecular, modeling, surveying, and geometric theorem proving. While two-dimensional constraint solving has been studied extensively, there still remain many open questions in the arena of three-dimensional problems. We first introduce some techniques presented by (Hoffmann and Vermeer, 1995). The constraint system Hoffmann has studied consists of six geometric elements and pairwise constraints between triples of the elements. The core idea is to solve the geometric constraint template problems. Based on this, we continue to demonstrate how to solve a special template system composed of three points and three planes. This constraint system includes the angle constraints between two planes that are not discussed before.

Feature is the fundamental design unit in modern solid modeling systems, and this makes a well defined feature interface a matter of concernment in the component based distributed modeling environment. This paper introduces a feature based modeling service framework and proposes an interface model of feature based modeling service toward such a modeling environment, including support of remote feature attachment and semantic maintenance. A prototype based feature interface definition strategy using procedural attaching and declarative validation mechanism is discussed and how the interface model tackles with the problems in distributed environment, such as locality transparently model reusing, is also explained.

In this paper, we propose an event specification language for event-based collaboration support software architecture, which incorporates some basic concepts, four event operators and four event-occurrence operators to conveniently allow complex event descriptions. The semantics of the language is also studied In the event specification language, we distinguish between event and event occurrence, identify primitive events, and introduce a small number of event operators for constructing composite (or complex) events. The novel aspect of our work lies in supporting a rich set of events and event expressions.

With the intensification of the competition in manufacture, the distributed technology, whose aim is to promote product design process, has changed the traditional CAD serial design approach. But the distributed design systems also bring some new problems such as design conflict. To avoid this inconsistent situation, there must be some coordination mechanisms. At the same time, these mechanisms must not constrain the freedom of the designers too much to take their creativity away. This paper introduces a feature-based distributed CAD system to support this collaborative work. We analyze the reason of the design conflict. For addressing this conflict, we present feature-based concurrency operation model. In such model, the feature is the basic atom that can be locked and excluded from other designers using. Comparing with part level concurrency system, this mechanism doesn't limit the design flexibility too much.

Shadow mapping has been a popular way of generating shadows in real-time applications, but it is still incapable of generating realistic real time soft shadows for area light. There is an algorithm for generating soft shadows for linear light with few samples, but the algorithm is not suitable for area light. The author presents a modified method to the shadow mapping algorithm for linear light. The new method can produce convincing soft shadows for area light in real time applications.

We describe an algorithm to watermark appearance attributes, as well as the shape of the mesh. Appearance attributes are potential watermarking primitives and the watermarking approach for them can be generalized from that for the shape. The major challenge of generalization is that the watermarking for appearance attributes has more constraints. We focus on this challenge. Especially for the normal vector, we embed the watermark by modifying its orientation, not magnitude. Results show our scheme effectively improves the capacity and enhances the robustness of mesh watermarking.

This paper proposes a virtual brush model based on droplet operation and its application on retrieving character outlines and character modeling in Chinese calligraphy style. In the proposed approach, a virtual brush model based on droplet operation is applied to produce vivid character outlines. The droplet model helps to compute stroke area with well-defined geometry information and leads to the feasibility to retrieve the outlines of characters with well-defined geometry representation. Further more, the variations of the model can express various Chinese brush styles, so by using the droplet model, we successfully overcome the poor expressive ability of the previous curve-offset method The complex evaluation of stroke area based on physical solid-model brush is also eliminated since the simplicity of the model.

In the field of computer graphics there is an increasing demand for non-photorealistic effects. We add the idea of pattern recognition guided by theoretical rules into a traditional NPR system and create non-photorealistic drawings intelligently. The Style Sample Library functions as an expert library and makes it easier to render a picture with nonphotorealistic effects even by an amateur user.

With the demand of distributed designers to cooperatively design a single product, these designers need to simultaneously access a common database, which holds the geometric model and other information of the product. But frequently, their design will lead to invalid results. Therefore, it is very important to build a distributed model to coordinate these designers to ensure the consistency of the product. The paper introduces a collaborative model to support this concurrent work. First, the architecture of this system is presented. Then a collaborative design model is described in detail. We analyze two reasons for the conflict and give two collaborative modes to coordinate the design process. These two modes can be used in different environments and can be used in a mixed way. So we can keep the consistency of the common solid model and maintain the maximal freedom of the designers at the same time. Finally, we give some design examples to further illustrate our model.

It is necessary to use libraries of parts when using CAD software. But, deficiencies and problems exist in most libraries, so we developed a part management system called GS-PM. Based on features, but not geometric information, it not only improves efficiency but also enables some applications of higher levels, for instance, the parts can be used in different CAD software. This part library can work in client/server mode to share information. It can also be applied to establish a customized visual part library (a Web part library), which can build parts dynamically according to the user's needs.

Feature based design is the main characteristic of current prevailing parametric solid modeling systems. By means of enabling users to build their own feature libraries, user defined features (UDF) provided as an extensional design method can overcome the shortcoming of inconvenience that exists in the traditional feature based modeling system. Traditional UDF representation is implemented either by procedural definition, which represents the features implicitly (J.J. Shah, 1991), or by an explicit representation or enumerative way (M.J. Pratt, 1989; M. Ranta and M. Mantyla, 1993). The paper proposes an innovative approach to the representation of UDFs by extending the common procedural UDFs' data structure with boundary features. Then a unified feature attachment interface is described. Thus, a unified representation of UDFs is introduced.

In this article we propose a hybrid modeling system based on B-rep model and volume model to overcome the inability of representing volume information of modeling object in conversional feature based modeling systems. Using this hybrid representation, we can easily solve the visualization and mass property computation for designing objects with specified volume attribute. In this article we propose a new method of converting B-rep models into volume models. This converting method is based on marching cube algorithm, and is optimized by octree algorithm. Using this converting method, we can efficiently convert the B-rep models into volume models. We also discuss the antialiasing technical on those volume models, we analyze different filters used for the voxelization of analytically described objects. To solve the visualization product problems in modeling systems, such as dynamic simulation, we present the methods of how to add Boolean operations on the hybrid modeling system to solve these problems. Voxelization enables uniform representation of all objects by a single primitive. Thus, instead of dealing with a number of different objects with specific features, dynamic simulation and dynamic interference on volume models only need simple calculations and is more efficient. We show that, using volume modeling, difficult problems in old modeling systems can be easily solved. The details of our algorithm are discussed in this article. We have implemented a volume modeling system based on our old feature based modeling system-GSCAD.

In distributed systems based on B/SM, events and event-condition-action rules are the fundamental metaphors for defining and enforcing the system. Processing entities execute behavior by reacting to and generating new events. It is important that event semantics is explicit. Although a lot of research has concentrated on event semantics, there still exists potential semantic ambiguity which is unacceptable in some circumstances. We propose an event model and incorporate an interaction group identifier into it. We emphasize that the semantics is a key to capture the actual meaning of events in real life, in which the same composite event patterns may imply totally different semantic meanings. Based on this observation, a graph-ESIG (Event and Service Interacting Graph) and ESIC (Event and Service Interacting Chain), which are constructed according to ECA-Rules, are proposed to trace events. ESIG greatly enhanced the expressive power to allow event detection correctly, which matches situations in reality. Finally, we develop a event detection algorithm that uses ESIG and ESIC.

The Knowledge-based Virtual Assembly System (KVAS) focuses on the generation, selection, evaluation, planning, optimization and simulation of mechanical product assembly in a virtual environment with the help of a knowledge-based system. The system we present uses the virtual environment as the user interface for engineers to manipulate the assembly interactively, together with a knowledge-based system as an intelligent assistant to do some automatic assembly planning.