Xiangxu Meng

LBVS: A Load Balancing Strategy for Virtual Storage

Cloud Storage is an important part of Cloud Computing, and it provides a way to achieve large scale storage architecture. And virtual storage is a strategy for Cloud Storage. A load balancing virtual storage strategy (LBVS) is proposed in this paper. The contribution of this strategy is that, it provides a large scale net data storage model and Storage as a Service model based on Cloud Storage. Three layers architecture is used to achieve storage virtualization, and two load balancing modules are used to balance systems load. This paper describes details of LBVS strategy, the model of virtual storage as well as how to implement the LBVS with iRODS and two load balancing algorithms.

Hermite variational implicit surface reconstruction

We propose a new technique for reconstructing surfaces from a large set of unorganized 3D data points and their associated normal vectors. The surface is represented as the zero level set of an implicit volume model which fits the data points and normal constraints. Compared with variational implicit surfaces, we make use of surface normal vectors at data points directly in the implicit model and avoid of introducing manufactured off-surface points. Given n surface point/normal pairs, the proposed method only needs to solve an n×n positive definite linear system. It allows fitting large datasets effectively and robustly. We demonstrate the performance of the proposed method with both globally supported and compactly supported radial basis functions on several datasets.

Specification and enforcement of flexible security policy for active cooperation

Interoperation and services sharing among different systems are becoming new paradigms for enterprise collaboration. To keep ahead in strong competition environments, an enterprise should provide flexible and comprehensive services to partners and support active collaborations with partners and customers. Achieving such goals requires enterprises to specify and enforce flexible security policies for their information systems. Although the area of access control has been widely investigated, current approaches still do not support flexible security policies able to account for different weighs that typically characterize the various attributes of the requesting parties and transactions and reflect the access control criteria that are relevant for the enterprise. In this paper we propose a novel approach that addresses such flexibility requirements while at the same time reducing the complexity of security management. To support flexible policy specification, we define the notion of restraint rules for authorization management processes and introduce the concept of impact weight for the conditions in these restraint rules. We also introduce a new data structure for the encoding of the condition tree as well as the corresponding algorithm for efficiently evaluating conditions. Furthermore, we present a system architecture that implements above approach and supports interoperation among heterogeneous platforms.

Grid-Enabled Workflow Management System Based On BPEL

A grid-enabled workflow management system provides a set of tools to facilitate building high-level grid application services by orchestrating low-level grid services. BPEL (Business Process Execution Language) is the de facto standard in the Web service community. The purpose of this paper is to design and implement a workflow management system based on BPEL in a grid environment. The approach to integrating BPEL with WSRF (Web Services Resource Framework), is to put forward a simple cluster model of BPEL engines and application component oriented workflow defining respectively to satisfy the specific requirements in a grid environment, such as stateful interactions, dynamic service binding, high throughput and scalability, and friendly workflow defining. Finally, a prototype of a workflow system implemented in ChinaGrid Supporting Platform (CGSP) is also given.

A RFID & Handheld Device-Based Museum Guide System

A museum guide system which is based on handheld devices (e.g. PDAs, short for Personal Digital Assistants) is presented in this paper. Radio-frequency identification (RFID) is used to navigate and get the index number of exhibit. Compared to traditional guide systems, such as tape or CD guide machine, this system provides visitors good visual and audio experience with multimedia technologies. Visitors can either roam at their pleasures and browse the expositive information from the device themselves, or sit on chairs searching for information and relevant interesting knowledge.

Towards high level SaaS maturity model: Methods and case study

This paper introduces a Software as a Service (SaaS) application which is designed and delivered in high level maturity model. In order to realize the configurability, metadata is used to define all the variability points of the application. Meanwhile, JMX is used to manage the metadata so that changed metadata can be hot deployed immediately during runtime. Scalability is discussed both in application layer and data layer. Integration requirements and roadmap between SaaS application and on-premise applications are introduced. Whats more, service surrogate extended from SCA and a message engine are used to meet the integration requirements in business processes.

Vector coevolving particle swarm optimization algorithm

In this paper, we propose a novel vector coevolving particle swarm optimization algorithm (VCPSO). In VCPSO, the full dimension of each particle is first randomly partitioned into several sub-dimensions. Then, we randomly assign either one of our newly designed scalar operators or learning operators to update the values in each sub-dimension. The scalar operators are designed to enhance the population diversity and avoid premature convergence. In addition, the learning operators are designed to enhance the global and local search ability. The proposed algorithm is compared with several other classical swarm optimizers on thirty-three benchmark functions. Comprehensive experimental results show that VCPSO displays a better or comparable performance compared to the other algorithms in terms of solution accuracy and statistical results.

G1 continuous approximate curves on NURBS surfaces

Curves on surfaces play an important role in computer aided geometric design. In this paper, we present a parabola approximation method based on the cubic reparameterization of rational Bezier surfaces, which generates G1 continuous approximate curves lying completely on the surfaces by using iso-parameter curves of the reparameterized surfaces. The Hausdorff distance between the approximate curve and the exact curve is controlled under the user-specified tolerance. Examples are given to show the performance of our algorithm. Highlights? We present a method to generate G1 continuous approximate curves on NURBS surfaces. ? We give the cubic reparameterizations of rational Bezier surfaces. ? The Hausdorff distance between the approximate and exact curves is controlled. ? The approximate curve is lying completely on the NURBS surface. ? Iso-parameter curves of the reparameterized surfaces constitute the resulting curve.

A BPEL4WS-based Composite Service Modeling Solution in Manufacturing Grid

In Manufacturing Grid, a lot of applications and resources in manufacturing enterprises are encapsulated as web services and a cooperative work environment is provided. Applying web service composition and workflow technologies, services are integrated into a composite service to represent a cooperative business process. Therefore the enterprise cooperation can be implemented by executing and monitoring the composite service. According to the characteristics of Manufacturing, this paper presents a composite service modeling solution based on BPEL4WS and discusses how this solution support BPEL4WS during the whole modeling process. The solution includes dynamic service discovery and service selection to support a flexible binding with the partners? services. This paper also describes how to execute and monitor the composite service.

A framework for physiological indicators of flow in VR games: construction and preliminary evaluation

Flow experience is often considered as an important standard of ideal user experience (UX). Till now, flow is mainly measured via self-report questionnaires, which cannot evaluate flow immediately and objectively. In this paper, we constructed a physiological evaluation model to evaluate flow in virtual reality (VR) game. The evaluation model consists of five first-level indicators and their respective second-level indicators. Then, we conducted an empirical experiment to test the effectiveness of partial indicators to predict flow experience. Most results supported the model and revealed that heart rate, interbeat interval, heart rate variability (HRV), low-frequency HRV (LF-HRV), high-frequency HRV (HF-HRV), and respiratory rate are all effective indicators in predicting flow experience. Further research should be conducted to improve the evaluation model and conclude practical implications in UX and VR game design.