bluuebunny/crossref_metadata_2025 huggingface dataset:
Particle Swarm Optimization Algorithms Inspired by Immunity-Clonal Mechanism and Their Applications to Spam Detection
Authors: Tan Ying
Published: April 2010

Compared to conventional PSO algorithm, particle swarm optimization algorithms inspired by immunity-clonal strategies are presented for their rapid convergence, easy implementation and ability of optimization. A novel PSO algorithm, clonal particle swarm optimization (CPSO) algorithm, is proposed based on clonal principle in natural immune system. By cloning the best individual of successive generations, the CPSO enlarges the area near the promising candidate solution and accelerates the evolution of the swarm, leading to better optimization capability and faster convergence performance than conventional PSO. As a variant, an advance-and-retreat strategy is incorporated to find the nearby minima in an enlarged solution space for greatly accelerating the CPSO before the next clonal operation. A black hole model is also established for easy implementation and good performance. Detailed descriptions of the CPSO algorithm and its variants are elaborated. Extensive experiments on 15 benchmark test functions demonstrate that the proposed CPSO algorithms speedup the evolution procedure and improve the global optimization performance. Finally, an application of the proposed PSO algorithms to spam detection is provided in comparison with the other three methods.
When I Seem More Important than T in IT
Authors: Gottschalk Petter
Published: April 2010

It has long been argued that information (I) is more important than technology (T) in information technology (IT). Thus in this case study, we will focus on information. The case is concerned with intelligence, which is the kind of information needed to prevent crime. This article starts by describing police intelligence, the case of U.S. intelligence strategy, and intelligence sources. Intelligence supports knowledge work as classified in the knowledge matrix. Next, technology is introduced in terms of the stages of growth model for knowledge management technology, since police intelligence work is conceptualized as knowledge work in this article.
It Takes Two to Tango
Authors: Spil Ton A.M. , van den Broek Tijs , Salmela Hannu T.T.
Published: April 2010

The view of evaluating Strategic Information Systems Planning (Grover & Segars, 2005) process and effectiveness has matured. However, the inter-organizational view or network view is understudied. The introduction of information strategy in networks seems more reactive than proactive; many organizations continue to use SISP as a way to support their internal decision-making process without actually cooperating with their business partners. This article aims to qualitatively explore and validate, respectively, context and process dimensions in two inter-organizational cases: a network of municipalities in Finland and a network of healthcare organizations in the Netherlands. The first case study explores the network context and theorizes how network context influences inter-organizational SISP, discovering that the inter-organisational SISP process is influenced by the context, especially by the role of trust and complexity. The second case study is the exploration of three process dimensions: contingency, certainty and contractual agreements.
An Open Source Software Evaluation Model
Authors: Confino Joel P. , Laplante Phillip A.
Published: April 2010

The allure of free, industrial-strength software has many enterprises rethinking their open source strategies. However, selecting an appropriate open source software for a given problem or set of requirements is very challenging. The challenges include a lack of generally accepted evaluation criteria and a multitude of eligible open source software projects. The contribution of this work is a set of criteria and a methodology for assessing candidate open source software for fitness of purpose. To test this evaluation model, several important open source projects were examined. The results of this model were compared against the published results of an evaluation performed by the Defense Research and Development Canada agency. The proposed evaluation model relies on publicly accessible data, is easy to perform, and can be incorporated into any open source strategy.
Performing Charlotte
Authors: Light Ann , Kleine Dorothea , Holloway Royal , Vivent Macarena
Published: April 2010

This article describes the use of a performed persona as a device in cross-cultural design activities. The device serves to elicit knowledge and manage expectations in the context of participatory design workshops to explore the purpose and function of a tool for tracing the supply chain of ethical goods from producer to consumer. The use of the method with the staff of a wine producer in Chile is analyzed and the benefits and challenges identified in using the form live in workshops. The authors conclude that the device offers potential but also requires some confidence and skill to invoke.
Agent-Based Middleware for Advanced Communication Services in a Ubiquitous Computing Environment
Authors: Suganuma Takuo , Takahashi Hideyuki , Shiratori Norio
Published: April 2010

In a ubiquitous computing (ubicomp) environment, system components of different types, including hardware elements, software components, and network connections, must cooperate mutually to provide services that fulfill user requirements. Consequently, advanced and flexible characteristics of software that are specialized for a ubicomp environment are needed. This article presents a proposal of an agent-based middleware for a ubicomp environment comprising computers and home electric appliances. The middleware, called AMUSE, can take quality of service (QoS) in a ubicomp environment into consideration by coping not only with user context but also with the resource context, using agent-based computing technology. Herein, we describe the concept, design, and initial implementation of AMUSE. Simulation results of an experimental ubiquitous service using AMUSE demonstrate the effectiveness of our proposed scheme. Additionally, to confirm our scheme’s feasibility and effectiveness, we describe the initial implementation of a multimedia communication application based on AMUSE.
Estimating which Object Type a Sensor Node is Attached to in Ubiquitous Sensor Environment
Authors: Maekawa Takuya , Yanagisawa Yutaka , Okadome Takeshi
Published: April 2010

By simply attaching sensor nodes to physical objects with no information about the objects, the method proposed in this article infers the type of the physical indoor objects and the states they are in. Assuming that an object has its own states that have transitions represented by a state transition diagram, we prepare the state transition diagrams for such indoor objects as a door, a drawer, a chair, and a locker. The method determines the presumed state transition diagram from prepared diagrams that matches sensor data collected from people’s daily living for a certain period. A 2 week experiment shows that the method achieves high accuracy of inferring objects to which sensor nodes are attached. The method allows us to introduce ubiquitous sensor environments by simply attaching sensor nodes to physical objects around us.
Integrating Access Control into UML for Secure Software Modeling and Analysis
Authors: Doan Thuong , Demurjian Steven , Michel Laurent , Berhe Solomon
Published: April 2010

Access control models are often an orthogonal activity when designing, implementing, and deploying software applications. Role-based access control (RBAC) which targets privileges based on responsibilities within an application and mandatory access control (MAC) that emphasizes the protection of information via security tags are two dominant approaches in this regard. The integration of access control into software modeling and analysis is often loose and significantly lacking, particularly when security is such a high-priority concern in applications. This article presents an approach to integrate RBAC and MAC into use-case, class, and sequence diagrams of the unified modeling language (UML), providing a cohesive approach to secure software modeling that elevates security to a first-class citizen in the process. To insure that a UML design with security does not violate RBAC or MAC requirements, design-time analysis checks security constraints whenever a new UML element is added or an existing UML element is modified, while post-design analysis checks security constraints across the entire design for conflicts and inconsistencies. These access control extensions and security analyses have been prototyped within a UML tool.
Security Requirements Engineering for Evolving Software Systems
Authors: Nhlabatsi Armstrong , Nuseibeh Bashar , Yu Yijun
Published: April 2010

Long-lived software systems often undergo evolution over an extended period. Evolution of these systems is inevitable as they need to continue to satisfy changing business needs, new regulations and standards, and introduction of novel technologies. Such evolution may involve changes that add, remove, or modify features; or that migrate the system from one operating platform to another. These changes may result in requirements that were satisfied in a previous release of a system not being satisfied in subsequent versions. When evolutionary changes violate security requirements, a system may be left vulnerable to attacks. In this article we review current approaches to security requirements engineering and conclude that they lack explicit support for managing the effects of software evolution. We then suggest that a cross fertilization of the areas of software evolution and security engineering would address the problem of maintaining compliance to security requirements of software systems as they evolve.
Engineering e-Collaboration Services with a Multi-Agent System Approach
Authors: Chiu Dickson K.W. , Cheung S.C. , Leung Ho-fung , Hung Patrick C.K. , Kafeza Eleanna , Hu Hua , Wang Minhong , Hu Haiyang , Zhuang Yi
Published: April 2010

With recent advances in mobile technologies and e-commerce infrastructures, there have been increasing demands for the expansion of collaboration services within and across systems. In particular, human collaboration requirements should be considered together with those for systems and their components. Agent technologies have been deployed in order to model and implement e-commerce activities as multi-agent systems (MAS). Agents are able to provide assistance on behalf of their users or systems in collaboration services. As such, we advocate the engineering of e-collaboration support by means of MAS in the following three key dimensions: (i) across multiple platforms, (ii) across organization boundaries, and (iii) agent-based intelligent support. To archive this, we present a MAS infrastructure to facilitate systems and human collaboration (or e-collaboration) activities based on the belief-desire-intension (BDI) agent architecture, constraint technology, and contemporary Web Services. Further, the MAS infrastructure also provides users with different options of agent support on different platforms. Motivated by the requirements of mobile professional workforces in large enterprises, the authors present their development and adaptation methodology for e-collaboration services with a case study of constraint-based collaboration protocol from a three-tier implementation architecture aspect. They evaluate our approach from the perspective of three main stakeholders of e-collaboration, which include users, management, and systems developers.
Autonomic Business-Driven Dynamic Adaptation of Service-Oriented Systems and the WSPolicy4MASC Support for Such Adaptation
Authors: Tosic Vladimir
Published: April 2010

When a need for dynamic adaptation of an information technology (IT) system arises, often several alternative approaches can be taken. Maximization of technical quality of service (QoS) metrics (e.g., throughput, availability) need not maximize business value metrics (e.g., profit, customer satisfaction). The goal of autonomic business-driven IT system management (BDIM) is to ensure that operation and adaptation of IT systems maximizes business value metrics, with minimal human intervention. The author presents how his WS-Policy4MASC language for specification of management policies for service-oriented systems supports autonomic BDIM. WS-Policy4MASC extends WS-Policy with new types of policy assertions: goal, action, probability, utility, and meta-policy assertions. Its main distinctive characteristics are description of diverse business value metrics and specification of policy conflict resolution strategies for business value maximization according to various business strategies. The author’s decision making algorithms use this additional WS-Policy4MASC information to choose the adaptation approach best from the business viewpoint.
Using Description Logics for the Provision of Context-Driven Content Adaptation Services
Authors: Yang Stephen J.H. , Zhang Jia , Huang Jeff J.S. , Tsai Jeffrey J.P.
Published: April 2010

This article presents our design and development of a description logics-based planner for providing contextdriven content adaptation services. This approach dynamically transforms requested Web content into a proper format conforming to receiving contexts (e.g., access condition, network connection, and receiving device). Aiming to establish a semantic foundation for content adaptation, we apply description logics to formally define context profiles and requirements. We also propose a formal Object Structure Model as the basis of content adaptation management for higher reusability and adaptability. To automate content adaptation decision, our content adaptation planner is driven by a stepwise procedure equipped with algorithms and techniques to enable rule-based context-driven content adaptation over the mobile Internet. Experimental results prove the effectiveness and efficiency of our content adaptation planner on saving transmission bandwidth, when users are using handheld devices. By reducing the size of adapted content, we moderately decrease the computational overhead caused by content adaptation.
Harnessing Information and Communication Technologies for Diffusing Connected Government Applications in Developing Countries
Authors: Ruhode E. , Owei V.
Published: April 2010

Improving information management practices is a key focus for many organisations across both the public and private sectors. An information society begins with a connected government and ICTs are the bedrock and founding pillars of such societies. To assist public administrators think beyond traditional e-government, this study describes a concept of connected government, whose philosophy rests on the integration story that happens behind the scenes of the visible web interface as well as the collaboration among government agencies. Diffusion of Innovations theory is the conceptual framework underpinning this study. The connected government phenomenon is also put into perspective by the systems theory that is explained in this study. This article describes a case study of an organisation in a developing country environment where even the basic e-government services are barely extant. This study was done to determine the connectedness within and across government agencies, with the idea of stimulating some thinking within and among public administrators, around the possibility that a connected government can indeed be established in a developing country setting. The study exposes shortcomings to e-government diffusion not only of the organisation under investigation, but also of other similar enterprises in developing countries within the same context. The paper concludes by proposing a set of recommendations toward diffusing connected government applications as an antidote to identified problems.
Adoption of Short Messaging Service (SMS) in Malaysia
Authors: Sulaiman Ainin , Zolait Ali Hussein Saleh
Published: April 2010

Short Messaging Service (SMS) being an almost instantaneous communication medium that connects people is now a phenomenon that has grown and spread around the globe at an amazing speed. Given the current trend of SMS usage and its potential growth, this paper provides an insight into SMS adoption. The study attempts to delineate the demographics and usage profile of SMS users in Malaysia, as well as explaining the factors influencing SMS adoption in Malaysia by using a modified version of the Technology Acceptance Model (TAM), which was originally introduced by Davis (1989). The study presents the demographic and usage profile in terms of gender, age, occupation, monthly personal income, extent of SMS usage and so forth of 489 SMS users from four institutions of education in the Klang Valley and Selangor. The present research uses and validates the scales for variables developed by earlier studies, namely perceived usefulness, perceived ease of use, perceived enjoyment, and perceived fees, which are hypothesized to be fundamental determinants of behavioural intention. The scale items for the said variables were tested for reliability, correlation and regression. The application of correlation analysis reveals a significant relationship among the independent variables, namely, perceived usefulness, perceived enjoyment, and perceived ease of use with the dependent variable that is behavioural intention. With regards to the level of importance derived from regression analysis, usefulness ranks the highest, followed by ease of use and enjoyment in explaining SMS adoption in Malaysia. Perceived fees do not seem to have a significant relationship with behavioural intention. Some implications, limitations and recommendations for future research are also discussed.
E-Government Initiative in the Sultanate of Oman
Authors: Al-Gharbi Khamis , Al-Kindi Ahmed
Published: April 2010

There are many interesting initiatives regarding the use of internet technologies in e-government that are taking place in developing countries. A number of studies have been conducted in recent years regarding the adoption and use of internet technologies in e-government. However, most of these studies focused on the developed countries. There are many interesting initiatives regarding the use of internet technologies in e-government that are taking place in the developing countries and yet have received very little research attention. The Sultanate of Oman is currently working on a project called e-Oman to provide e-government, e-commerce, e-learning and other e-services. The hope is to enhance the quality of services offered by the government to its citizens. The purpose of this paper is to highlight e-government Initiatives in Oman.
Material Cultures and Moral Mediators in Human Hybridization
Authors: Magnani Lorenzo
Published: April 2010

We already are hybrid humans, fruit of a kind of co-evolution of both our brains and the common, scientific, social, and moral knowledge we have produced by ourselves starting from the birth of material culture with our ancestors until the recent effects generated by the whole field of technological artifacts and of information and communication technologies (ICTs). We all are “constitutively” natural-born cyborgs, that is biotechnological hybrid minds. Our minds should not be considered to be located only in the head: human beings have solved their problems of survival and reproduction, “distributing” cognitive and ethical functions to external nonbiological sources, props, and aids, which originate cultures. The paper also illustrates the interplay between cultures and distributed cognition and stresses the role of some technological artifacts as moral mediators. The second part of the paper is related to the analysis of the interplay between cultures, morality, and cognition and of some consequences concerning the problem of intercultural communication in the light of the role of moral mediators, docility, and cyberprivacy. Finally, I discuss some suggestions concerning the problem of what I call the moral principle of isolation of cultures, with respect to the effects of ICTs.
The Ethics of Cyberweapons in Warfare
Authors: Rowe Neil C.
Published: April 2010

The author discusses the ethical issues of using cyberweapons, software that attacks data and other software during warfare. Many people assume these are relatively benign weapons, but we argue that they can create serious harms like any weapon. He defines cyberweapons and describes them in general terms, and survey their status as per the laws of war. He then discusses the unreliability of cyberweapons, the problem of collateral damage, and the associated problems of damage assessment, maintenance of secrecy, and mounting cyber-counterattacks. He examines some possibilities for creating more ethical cyberweapons and discusses the alternative of cyber-blockades. He concludes that cyberattacks should generally be outlawed by international agreement.
Shaping the Ethics of an Emergent Field
Authors: Anderson Alison , Petersen Alan
Published: April 2010

Nanotechnologies present significant new challenges for the study of technoethics. While they are surrounded by high expectations there is considerable uncertainty about their impact. Discussions about their likely ethical implications have often assumed that ethical issues and standpoints are relatively clear. The commonly held narrow utilitarian conception of benefits versus risks tends to overlook broader issues concerning the operation of power in problem definition, unimagined or unknown effects, and accountability. Drawing upon data from a recent UK-based study, this article examines how scientists’ and policymakers’ representations of nanotechnologies contribute to shaping thinking about the ‘ethics’ of this field. It suggests that their particular framing of the field is likely to constrain debate on a range of important matters in need of urgent deliberation, including the direction of current research efforts and whether the investments in particular lines of research are likely to bring about the promised economic and social benefits or have deleterious impacts. Overall, the study found that most of the respondents were optimistic about the perceived benefits of nanotechnologies and sought to distance their work from wider non-technical questions. Scientists and policymakers, it is argued, need to reflect much more upon their own assumptions and consider how these may influence the trajectory of technology development and public responses.
A Framework for Integrating the Social Web Environment in Pattern Engineering
Authors: Kamthan Pankaj
Published: April 2010

In the last decade, patterns have emerged as a notable problem-solving approach in various disciplines. This paper aims to address the communication requirements of the elements of pattern engineering (namely, actors, activities, and artifacts) in general and the pattern realization process in particular. To that regard, a theoretical framework using the Social Web as the medium is proposed and its implications are explored. The prospects of using the Social Web are analyzed by means of practical scenarios and concrete examples. The concerns of using the Social Web related to cost to actors, decentralization and distribution of control, and semiotic quality of representations of patterns are highlighted. The directions for future research including the use of patterns for Social Web applications, and the potential of the confluence of the Social Web and the Semantic Web for communicating the elements of pattern engineering, are briefly explored.
Luciano Floridi's Metaphysical Theory of Information Ethics
Authors: Spence Edward
Published: April 2010

This paper falls into five main parts. Part one, offers a critical analysis and evaluation of Luciano Floridi’s metaphysical theory of information ethics (IE). Drawing on part one, part two provides a discussion of what I consider to be the main conceptual and practical difficulties facing Floridi’s IE theory. Although in agreement with the overall motivation and objective that informs Floridi’s IE position, namely, that “all entities, qua informational objects, have an intrinsic moral value…” and that “there seems to be no good reason not to adopt a higher and more inclusive, ontocentric [moral] perspective” (Floridi, 2007, 10), part three of the paper proposes an alternative New-Gewirthian approach to Information Ethics that avoids some if not all of the difficulties facing Floridi’s own position. Part four then examines the implications for Floridi’s metaphysical theory of information ethics and finally, offers a conclusion in part five.
Working Together to Improve Usability
Authors: Nørgaard Mie , Hornbæk Kasper
Published: April 2010

In theory, usability work is an important and well-integrated activity in developing software. In practice, collaboration on improving usability is ridden with challenges relating to conflicting professional goals, tight project schedules, and unclear usability findings. The authors study those challenges through 16 interviews with software developers, usability experts, and project managers. Four themes that are key challenges to successful interaction between stakeholders are identified: poor timing when delivering usability results, results lacking relevance, little respect for other disciplines, and difficulties sharing important information. The authors review practices that have successfully addressed these challenges and discuss their observations as encompassing multiple perspectives and as a collaborative cross-professional learning process.
Simulating Social Network Formation
Authors: Gilles Robert , James Tabitha , Barkhi Reza , Diamantaras Dimitrios
Published: April 2010

Social networks depict complex systems as graph theoretic models. The study of the formation of such systems (or networks) and the subsequent analysis of the network structures are of great interest. For information systems research and its impact on business practice, the ability to model and simulate a system of individuals interacting to achieve a certain socio-economic goal holds much promise for proper design and use of cyber networks. We use case-based decision theory to formulate a customizable model of information gathering in a social network. In this model, the agents in the network have limited awareness of the social network in which they operate and of the fixed, underlying payoff structure. Agents collect payoff information from neighbors within the prevailing social network, and they base their networking decisions on this information. Along with the introduction of the decision theoretic model, we developed software to simulate the formation of such networks in a customizable context to examine how the network structure can be influenced by the parameters that define social relationships. We present computational experiments that illustrate the growth and stability of the simulated social networks ensuing from the proposed model. The model and simulation illustrates how network structure influences agent behavior in a social network and how network structures, agent behavior, and agent decisions influence each other.
Privacy and Security for Virtual Communities and Social Networks
Authors: Michaelides Georgios , Hosszú Gábor
Published: April 2010

The importance of the virtual communities’ privacy and security problems comes into prominence by the rapid development of online social networks. This article presents the multiple threats currently plaguing the virtual world, Internet privacy risks, and recommendations and countermeasures to avoid such problems. New generations of users feel comfortable publishing their personal information and narrating their lives. They are often unaware how vulnerable the data in their public profiles are, which a large audience daily accesses. A so-called digital friendship is built among them. Such commercial and social pressures have led to a number of privacy and security risks for social network members. The article presents the most important vulnerabilities and suggests protection methods and solutions that can be utilized according to the threat. Lastly, the authors introduce the concept of a privacy-friendly virtual community site, named CWIW, where privacy methods have been implemented for better user protection.
The Centralisation Dilemma in Educational IT
Authors: Weller Martin
Published: April 2010

The trend with organisational adoption of virtual learning environments (VLE) seems to be cyclical. Initially, a decentralised approach was adopted, wherein each department implemented different learning environments or mixtures of technology, often developed in-house. The last five years have seen an increased centralisation of learning environment implementation, with most universities adopting a single VLE. However, in more recent times the proliferation of free, easy-to-use third party tools that fulfil a range of functions has seen a desire amongst some educators to return to a more decentralised model of technology provision, by supporting Personal Learning Environments (PLE). This paper examines the issues surrounding both a centralised and decentralised model. These include pedagogic, support, financial, reliability, data and technical issues. The conclusion is that although the fully individualised PLE may not be possible or desirable in higher education, maintaining separate, often inferior versions of commonly available software is not a sustainable position.
Some Key Success Factors in Web-Based Corporate Training in Brazil
Authors: Joia Luiz Antonio , Costa Mário Figueiredo
Published: April 2010

Brazilian companies are increasingly turning to Web-based corporate training by virtue of the fact that they need to train their employees within tight budget constraints in a country of continental dimensions. However, most of these companies do not know what the critical success factors in these endeavors are. Therefore, this article seeks to investigate some key success factors associated with such digital enterprises. In order to achieve this, the multiple case study method is used, whereby two cases, both conducted within the same Brazilian company, leading to opposite outcomes—a success and a failure—are analyzed in depth. The conclusions reached in this article were that goal orientation, source of motivation, and metacognitive support were the three critical dimensions in these two Web-based corporate training programs under analysis. Lastly, some managerial implications of these results are outlined.
User Facing Web Services in Portals
Authors: Polgar Jana
Published: April 2010

In SOA framework, Portal applications aggregate and render information from multiple sources in easily consumable format to the end users. Web services seem to dominate the integration efforts in SOA. Traditional data-oriented web services require portlet applications to provide specific presentation logic and the communication interface for each web service. This approach is not well suited to dynamic SOA based integration of business processes and content. WSRP 2.0 aim at solving the problem and providing the framework for easy aggregation of presentation services.Is not practical to publish portlets locally if the organisation wishes to publish their portlets as web services to allow their business partners using these services in their portals. UDDI extension for WSRP enables the discovery and access to user facing web services while eliminating the need to design local user facing portlets. Most importantly, the remote portlets can be updated by the web service providers from their own servers.
Do You Need Content Management System?
Authors: Polgar Jana
Published: April 2010

Today the Web is used as a means to allow people and business to use services, get information and conduct transactions. Businesses today depend upon their visibility in their respective marketplaces and provision of e-services to customers. The Internet has become an important delivery mechanism of business visibility. Internet also significantly extends businesses capabilities to sell and buy worldwide. Therefore, the company website plays important role in maintaining and extending the business opportunities over the Internet.
Lotus Workforce Management-
Authors: O’Connor Jerh. , Dalton Ronan , Naro Don
Published: April 2010

Human Resources departments are often burdened with administrative tasks performed on behalf of employees who lack the tools necessary to complete these tasks themselves. A software approach known as self-service aims to streamline HR processes by providi
WSBen
Authors: Oh Seog-Chan , Lee Dongwon
Published: April 2010

In this article, a novel benchmark toolkit, WSBen, for testing web services discovery and composition algorithms is presented. The WSBen includes: (1) a collection of synthetically generated web services files in WSDL format with diverse data and model characteristics; (2) queries for testing discovery and composition algorithms; (3) auxiliary files to do statistical analysis on the WSDL test sets; (4) converted WSDL test sets that conventional AI planners can read; and (5) a graphical interface to control all these behaviors. Users can fine-tune the generated WSDL test files by varying underlying network models. To illustrate the application of the WSBen, in addition, we present case studies from three domains: (1) web service composition; (2) AI planning; and (3) the laws of networks in Physics community. It is our hope that WSBen will provide useful insights in evaluating the performance of web services discovery and composition algorithms. The WSBen toolkit is available at: http://pike.psu.edu/sw/wsben/.
A Federated Approach to Information Management in Grids
Authors: Aktas Mehmet S. , Fox Geoffrey C. , Pierce Marlon
Published: April 2010

We propose a novel approach to managing information in grids. The proposed approach is an add-on information system that provides unification and federation of grid information services. The system interacts with local information services and assembles their metadata instances under one hybrid architecture to provide a common query/publish interface to different kinds of metadata. The system also supports interoperability of major grid information services by providing federated information management. We present the semantics and architectural design for this system. We introduce a prototype implementation and present its evaluation. As the results indicate, the proposed system achieves unification and federation of custom implementations of grid information services with negligible processing overheads.
Apparent Activation Energy in Low Temperature Aging of Y-TZP Ceramics
Authors: Xie Qi Fei , Wang Cheng , Zan Qing Feng , Dong Li Min
Published: April 2010

Apparent activation energy in low temperature aging of two kinds of Y-TZP ceramic was studied in this paper. The ceramics were processed into small pieces, and aging in 100°C, 110°C, 120°C, 130°C and 140°C respectively. The content of monoclinic phase was calculated by X-ray diffraction patterns and the microstructure was scanned by SEM. According to MAJ law and Arrhenius formation, straight lines were fitted in coordinate systems of ln (ln (1/(1 − f )))-ln t and ln b-1/T, and the kinetic parameters of low temperature aging of Y-TZP ceramic were calculated according to these lines. The results revealed that grain size significantly affected apparent activation energy of Y-TZP ceramics.
Effects of Different Heat Treatment Temperatures on the Properties of Quartz Fibers
Authors: Wei Qi Hong , Wang Chong Hai , Cheng Zhi Qiang , Li Ling , Wang Hong Sheng , Wei Zhong Hua , Gao Fang
Published: April 2010

In this paper, XRD was engaged in studying phase transformation of quartz fibers, SEM was engaged in studying the surface micromorphology of quartz fibers heat treated at different temperatures, and the tensile strength was measured by a single fiber strength electronics instrument. The results indicate that surface infiltration agent have been iliminated after heat treatment at 500°C, and the tensile strength decreaced significantly. The higher the temperature was, the more the tensile strength decreaced. There were no significant phase transformation and no crystallization heat treatmented at 500~800°C. But there were some round and strip bulges, and scap defects on the surface. With temperature increasing,some scab defects and bulges began to flake off, and some new rifts and cracks were formed. This was one of the important factors that decreaced tensile strength markedly.
Fabrication and Properties of Si3N4-SiC-C Refractory Composites
Authors: Xu You Guo , Jiang Bin , Huang Zhao Hui , Fang Ming Hao , Liu Yan Gai
Published: April 2010

Si3N4-SiC-C refractory composites were prepared under the condition of 1450°C × 3h with electrofoging anthracite, Si3N4, SiC as the raw material and the modification emulsified bitumen as the binder. The effects of the silicon and silica fine powder additives on the compressive strength of Si3N4- SiC-C refractory composites were studied. The results indicated that adding an appropriate ratio range of silicon or silica fine powder in the composites both can improve the compressive strength of the material.
Mechanical Properties of Al-Si Alloy-Based Composites Reinforced by In Situ TiB2 Particulates
Authors: Yao Jun Ping , Zhong Sun , Zhang Lei , Zhao Huo Ping
Published: April 2010

Al–Si alloy-based composites are widely used in automotive, aerospace and mineral processing industries with improved properties. In situ techniques have been developed to fabricate Al–Si alloy-based composites, which can lead to better adhesion at the interface and hence better mechanical properties. Al–Si alloy reinforced with in situ TiB2 particles was synthesized successfully by using salt reaction route. These in situ composites have shown significant improvement in mechanical properties compared with the base alloy. The wear resistance of the alloy is also significantly improved with the addition of TiB2 particles. The hardness, strength and wear resistance are strengthened with increasing TiB2 content of the composites. TiB2 can act not only as a grain refiner for primary Al but also as a modifier of Si in eutectic mixture. Analysis of the worn surface of Al–Si/TiB2 composites tested under loads of 30 and 110N suggests that ploughing is predominant at lower loads and delamination is predominant at higher loads.
Numerical Simulation of Flow-Induced Corrosion in One-Strand Tundish
Authors: Zhang Mei Jie , Lin Xiao Long , Yan Wu , Ao Huang
Published: April 2010

Flow control devices made of refractories are established in the tundish to modify the flow characteristics. In practical producing, the metallurgical function of flow control devices is weakened because of refractories corrosion. In this subject, an index named refractory wear factor which is used to evaluate the refractory wear was defined at first. And then, the characteristics of molten steel flow and the distribution of temperature and the refractory wear factor in a one-strand tundish equipped with flow control devices of a turbulence inhibitor, a weir and a dam were numerically simulated using the commercial CFD software. At last, the influence on refractory wear factor was analyzed. The following results were obtained. The high-speed molten steel is mainly confined to the injecting zone, especially to the turbulence inhibitor. The walls around the entering zone tundish and the weir wall faced to the flow direction have higher temperature than other walls. The highest value of refractory wear factor is focused on the inhibitor and bottom wall near the outlet. In order to keep the synchronization for the tundish, the refractories used in those zones should have higher anti-wear properties.
Thermal Fatigue Behavior of Ladle Purging Plug
Authors: Zhang Hui , Hong Yan Ruo , Li Hong Xia , Bin Yang
Published: April 2010

The thermal fatigue behavior of alumina-magnesia based and alumina-chromia based purging plug materials are comparatively studied. By comparing thermal shock parameters, the changes of elastic modulus and hot modulus of rupture after thermal shock cycles, we come to a conclusion that microcracks emerge in the alumina-magnesia based material, which hinder the crack growth during thermal shock cycles. The fine-grained and network structure of alumina-magnesia based material are also helpful to improve thermal shock resistance. However, cracks are difficult to form in the alumina-chromia based material but it tends to fracture damage quickly once the cracks nucleation due to coarse-grained structure of alumina-chromia based material.
Oxidation Properties of ZrB2-20vol.%SiC-10vol.%BN Ceramic Composite at 1200°C
Authors: Li Gang , Han Wen Bo
Published: April 2010

Dense ZrB2-20vol.%SiC-10vol.%BN (ZSB) ceramic composites by introducing BN as the third phase are fabricated through hot pressing sintering under inert gas protected. The static oxidation behavior of the ZrB2-SiC-BN ceramic composite at 1200°C in air is analyzed using differential thermal analysis technique, and the surface morphology of the composites after oxidation at 1200°C is examined using scanning electron microscopy along with energy dispersive spectroscopy. The microstructure change and oxidation behaviors of the ZrB2-SiC-BN ceramic composite are investigated. The effect of BN grain size is analyzed and the oxidation mechanism in ceramic composites is discussed correspondingly.
Fabrication and Superplastic Deformation of Al2O3/YSZ/MgAl2O4 Composite Ceramic
Authors: Chen Guo Qing , Zu Yu Fei , Xie Jie , Fu Xue Song
Published: April 2010

High strain rate superplastic forming is the key issue of the industrial application of superplastic ceramic and is also an effective approach to achieve “near-net shaping” of ceramic parts with complicated shape. The sol-gel method was adapted to synthesize the nano-sized composite powders. A three-phase nanocomposite ceramic Al2O3-30mol%YSZ-30mol%MgAl2O4 (AZ30S30) was prepared by using hot-pressing sintering in vacuum. Then the superplastic forming of a ceramic part with relatively complicated shape was accomplished and some new characters in superplastic forming were studied. The results demonstrate that as-sintered ceramic is a typical inter/intra granular nano-structured composite. Because the dispersed second phase inhibited the growth of the alumina matrix grains in deformation as well as in sintering, the material behaves excellent superplastic formability. The extrusion forming at a high strain rate was achieved and the part in cup shape was obtained. The yttrium element segregated obviously at the grain boundary after deformation, which demonstrated that the yttrium element directionally diffused during the deformation. The mechanical properties of the ceramic did not change much after extrusion. The maximum hardness of as-deformed composite ceramic is 32GPa, a litter lower than that of 35GPa before deformation.
Phase Formation Route of Cr2AlC Ceramics from Cr, Al and Graphite Powders
Authors: Guan Chun Long , Liu Guo Qin , Shan Ying Chun
Published: April 2010

Cr2AlC ceramics (Cr:Al:C =1:1.2:1 mol.%) were synthesized by powder metallurgical method in argon in the temperature range of 700 to1250°C using Cr, Al and graphite powders as the initial materials. The phase relationships during reaction in the ternary system Cr-Al-C were investigated. The products were characterized by X-ray diffraction (XRD) and differential thermal analysis (DTA). It was found that Cr9Al17, Al8Cr5 and Cr2Al intermediate phases were formed in turn with increase of temperature. Up to 1050°C, with consumption of Cr9Al17 and Al8Cr5 phases completely, the amount of Cr2Al increased significantly. Single phase Cr2AlC with small amount of Cr7C3 was produced until 1250°C. Combined with the results of differential thermal analysis (DTA) and X-ray diffraction (XRD), it is revealed that Cr2AlC phase is formed by the reaction of Cr–Al intermetallic compounds, Cr, Al and graphite. In addition, the reaction equations of the process from 660 to1250°C were given.
Ablation Resistant of Pressureless Sintered ZrB2-Based Ceramics
Authors: Zhou Chang Ling , Wang Yan Yan , Cheng Zhi Qiang , Wang Chong Hai , Fan Jie , Sun Cheng Gong , Feng Bao Lin
Published: April 2010

ZrB2-SiC and ZrB2-SiC-C ultra-high temperature ceramics (UHTCs) were fabricated by pressureless sintering under an argon atmosphere. The mass and linear ablation rates were tested in an oxyacetylene flame with high velocity. The microstructure and phase transformation of the ZrB2-based UHTCs were characterized by scanning electron microscopy along with energy dispersive spectrometry. Results show that the UHTCs have excellent properties of ablation resistance at ultra-high temperature. The values of mass and linear ablation rates were lower in the ZrB2-SiC UHTCs than those measured for ZrB2-SiC-C. The effect of C addition on the ablation resistant was not obvious but it influenced the microstructure of the ZrB2-SiC UHTCs. And the ablation resistant mechanisms of ZrB2-based UHTCs were discussed according to microstructure analysis.
Fabrication of Layered-Ternary Ti3AlC2 Ceramics by High Energy Milling and Hot Pressing Sintering
Authors: Zhu Jian Feng , Qi Guo Quan , Liu Bo Bo , Wang Fen
Published: April 2010

Fully dense and single-phase Ti3AlC2 bulk ceramic was successfully fabricated by a high energy milling and hot-pressing with Ti, C and Al as starting materials. The details of reaction and phase evolution in high energy milling and hot pressing sintering were investigated. The results show that most of the starting materials transform to Ti-Al intermetallics and TiC in high-energy milling. The as milled powders react into Ti2AlC firstly in hot pressing sintering. When the temperature raise high enough, the Ti2AlC transform to Ti3AlC2. The content of aluminum is higher than that in the theoretical composition, which is attributing to the volatilization of Al at high temperature.
Solution-Based Synthesis of Ultra-Fine ZrB2 Powders and ZrB2-SiC Composite Powders
Authors: Che Xiao Pan , Zhu Shi Zhen , Yang Li Juan , Xu Qiang
Published: April 2010

Ultra-fine ZrB2 powders and ZrB2-SiC composite powders were synthesized by solution-based method, using zirconium oxynitrate (ZrO(NO3)2•2H2O), boric acid (H3BO3), phenolic resin, and tetraethyl orthosilicate (TEOS) as raw materials, respectively. The zirconia sol with other precursor was formed via adjustment of the pH value. After drying, grinding and sieving, the precursor powders were obtained. Exposed to carbothermal reduction heat treatments (1300°C~1500°C, 0.5h, flowing argon), pure ZrB2 powders and ZrB2-SiC composite powders with fine particle size (~1μm) were synthesized.
Properties and Structure of Micro Porous Mullite-Corundum Refractory with High Strength
Authors: Wu Juan , Yang Dao Yuan , Zhu Kai , Zhang Rui
Published: April 2010

Mullite- corundum ceramic was fabricated using bauxite and silica fume as raw materials by gel-casting process. The fluidity of the slurry, as well as strength, apparent porosity, pore size distribution, phase composition and microstructure of sintered specimen were studied. The results showed that: the slurry had low viscosity, good fluidity for casting if pH=9, dispersant 0.33wt% and solid content 60vol%; the strength of material came up to 165MPa even if the apparent porosity was about 30%; the samples were characterized by mullite 70%, corundum 22%, rutile 3%, glass phase only 5%, the size of majority grains was about 2μm, and most crystals with high melting point bonded directly; the average aperture was 264nm, the pore size distribution were divided into 2~30nm, 45~60nm and 1500~4000nm three regions. The distribution probability of nano- aperture was the largest, the volume of micron -aperture was the maximum, but all pores were less than 4μm in diameter, which suggested that the materials had micro porous characteristics. The microcrystalline, crystals combined directly and micro porous structure leaded to high strength of the refractory materials together.