Cross-Layer Optimization in OFDM Wireless Communication Network

The wide use of OFDM systems in multiuser environments to overcome problem of communication over the wireless channel has gained prominence in recent years. Cross-layer Optimization technique is aimed to further improve the efficiency of this network. This chapter demonstrates that significant improvements in data traffic parameters can be achieved by applying cross-layer optimization tech- niques to packet switched wireless networks. This work compares the system capacity, delay time and data throughput of QoS traffic in a multiuser OFDM system using two algorithms. The first algorithm, Maximum Weighted Capacity, uses a cross-layer design to share resources and schedule traffic to users on the network, while the other algorithm (Maximum Capacity) simply allocates resources based only on the users channel quality. The results of the research shows that the delay time and data throughput of the Maximum Weighted Capacity algorithm in cross layer OFDM system is much better than that of the Maximum Capacity in simply based users channel quality system. The cost incurred for this gain is the increased complexity of the Maximum Weighted Capacity scheme

Information Systems Change and Social Interaction: A Research Agenda

As the investments in IT are still growing and organizations are more dependent on IT than ever before practitioners as well as researchers are still lacking theories or models that help and explain if and when IT has to be adapted, partly exchanged or entirely implemented. In this paper we claim that one major reason for IS change lies in the interaction of human agents while using IT to solve tasks. Human agents cooperate within and simultaneously build a social network that is partly selforganizing, dynamic and uncontrollable from the outside. This dynamic can cause unintended pressure on the use and the usability of IT and therefore may force organizations to change the IS. This article discusses the Structurational Model of IT and concepts of the Social Network Analysis and draws several implications of examining the impact of social interaction on IS change

Information systems, software engineering, and systems thinking: challenges and opportunities

This article traces past research on the application of the systems approach to information systems development within the disciplines of information systems and software engineering. Their origins historically are related to a number of areas, including general systems theory. While potential improvement of software development practices is linked by some leading experts to the application of more systemic methods, the current state of the practice in software engineering and information systems development shows this is some way from being achieved. The authors propose possible directions for future research and practical work on bringing together both fields with systems thinking

Evaluating follow- up and complexity in cancer clinical trials (EFACCT): an eDelphi study of research professionals’ perspectives.

Objectives: To evaluate patient follow-up and complexity in cancer clinical trial delivery, using consensus methods to: (1) identify research professionals’ priorities, (2) understand localised challenges, (3) define study complexity and workloads supporting the development of a trial rating and complexity assessment tool (TRACAT). Design: A classic eDelphi completed in three rounds, conducted as the launch study to a multiphase national project (evaluating follow-up and complexity in cancer clinical trials). Setting: Multicentre online survey involving professionals at National Health Service secondary care hospital sites in Scotland and England varied in scale, geographical location and patient populations. Participants: Principal investigators at 13 hospitals across nine clinical research networks recruited 33 participants using pre-defined eligibility criteria to form a multidisciplinary panel. Main outcome measures: Statements achieving a consensus level of 70% on a 7-point Likert-type scale and ranked trial rating indicators (TRIs) developed by research professionals. Results: The panel developed 75 consensus statements illustrating factors contributing to complexity, follow-up intensity and operational performance in trial delivery, and specified 14 ranked TRIs. Seven open questions in the first qualitative round generated 531 individual statements. Iterative survey rounds returned rates of 82%, 82% and 93%. Conclusions: Clinical trials operate within a dynamic, complex healthcare and innovation system where rapid scientific advances present opportunities and challenges for delivery organisations and professionals. Panellists highlighted cultural and organisational factors limiting the profession’s potential to support growing trial complexity and patient follow-up. Enhanced communication, interoperability, funding and capacity have emerged as key priorities. Future operational models should test dialectic Singerian-based approaches respecting open dialogue and shared values. Research capacity building should prioritise innovative, collaborative approaches embedding validated review and evaluation models to understand changing operational needs and challenges. TRACAT provides a mechanism for continual knowledge assimilation to improve decision-making

Sustainability of systems interoperability in dynamic business networks

Dissertação para obtenção do Grau de Doutor em Engenharia Electrotécnica e de ComputadoresCollaborative networked environments emerged with the spread of the internet, contributing to overcome past communication barriers, and identifying interoperability as an essential property to support businesses development. When achieved seamlessly, efficiency is increased in the entire product life cycle support. However, due to the different sources of knowledge, models and semantics, enterprise organisations are experiencing difficulties exchanging critical information, even when they operate in the same business environments. To solve this issue, most of them try to attain interoperability by establishing peer-to-peer mappings with different business partners, or use neutral data and product standards as the core for information sharing, in optimized networks. In current industrial practice, the model mappings that regulate enterprise communications are only defined once, and most of them are hardcoded in the information systems. This solution has been effective and sufficient for static environments, where enterprise and product models are valid for decades. However, more and more enterprise systems are becoming dynamic, adapting and looking forward to meet further requirements; a trend that is causing new interoperability disturbances and efficiency reduction on existing partnerships. Enterprise Interoperability (EI) is a well established area of applied research, studying these problems, and proposing novel approaches and solutions. This PhD work contributes to that research considering enterprises as complex and adaptive systems, swayed to factors that are making interoperability difficult to sustain over time. The analysis of complexity as a neighbouring scientific domain, in which features of interoperability can be identified and evaluated as a benchmark for developing a new foundation of EI, is here proposed. This approach envisages at drawing concepts from complexity science to analyse dynamic enterprise networks and proposes a framework for sustaining systems interoperability, enabling different organisations to evolve at their own pace, answering the upcoming requirements but minimizing the negative impact these changes can have on their business environment

Salient complexities of engaging external consultants in information systems projects

Project sponsors have sought to develop the necessary competence to address various challenges they face during project development, implementation, and exploitation by employing different initiatives including the engagement and use of external consultants. However, doing so is associated with a number of consequences, including a significant risk of exacerbating project complexities. With this in mind, we set out in this article to examine the salient differences in the key project complexities between projects engaging consultants and those not engaging consultants. Data are obtained from 146 project management practitioners engaged in projects in Canada and the USA. Data analysis is undertaken using three-way multidimensional scaling. Findings as relates to the key complexities associated with information systems projects, points to the manifestation of six broad dimensions of complexity namely 1) “Variety,” 2) “Control,” 3) “Criticality,” 4) “Scope and repetition,” 5) “Information,” and 6) “Dependence.” As relates to how consultant engagement changes the salience of these key project complexities, we find that consultant engagement leads to more varied and stronger structural complexity and higher salience of interpersonal and organizational complexity

Salient complexities of engaging external consultants in information systems projects

Project sponsors have sought to develop the necessary competence to address various challenges they face during project development, implementation and exploitation by employing different initiatives including the engagement and use of external consultants. However, doing so is associated with a number of consequences, including a significant risk of exacerbating project complexities. With this in mind, we set out in this study to examine the salient differences in the key project complexities between projects engaging consultants and those not engaging consultants. Data is obtained from 146 project management practitioners engaged in projects in Canada and the United States. Data analysis is undertaken using 3-way Multidimensional Scaling (MDS). Findings as relates to the key complexities associated with information systems projects, points to the manifestation of six broad dimensions of complexity namely (i) ‘Variety’ (ii) ‘Control’ (iii) ‘Criticality’ (iv) ‘Scope and repetition’ (v) ‘Information’ and (vi) ‘Dependence’. As relates to how consultant engagement changes the salience of these key project complexities, we find that consultant engagement leads to more varied and stronger structural complexity and higher salience of interpersonal and organisational complexity

Framework to assist organisations with information technology adoption governance

The evidence from the literature suggests that Information Technology adoption (IT) governance in organisations is still a challenge. The diversity of application and the ever-increasing use of IT results in making decisions on IT adoption a major challenge for organisations. The decision about using a particular technology from an organisational perspective is problematic since individual users have different worldviews. The implicit assumption in IT adoption literature is that stakeholders always reach consensus during IT adoption decision making in organisations. This study explored the existing models and frameworks in order to develop a preliminary improved IT adoption governance framework. This study used a case study sequential explanatory mixed methods research approach to validate the preliminary IT adoption governance framework. The first validation phase of the framework was done using a quantitative approach followed by the second validation phase based on qualitative interviews. The last validation was done after integrating the quantitative and qualitative results to produce the refined framework. The results suggest that the developed framework may improve IT adoption governance in organisations. The results showed that the framework components facilitate IT adoption governance in organisations. The results also suggest that the components have an association with each other except for the Technology Acceptance Model component. The results indicate that stakeholder participation and hard systems thinking components have a strong predictive impact on IT governance framework component perception in organisations. The study results suggest that IT adoption decision makers need to balance different stakeholders’ demands during IT adoption decision making in organisations. The framework helps in that regard by reconciling different stakeholders’ demands through collective IT adoption decision making. The strength of the framework is its integration of theories from various disciplines in understanding stakeholder expectations. On that basis the framework is in a better position to offer more insight into understanding challenges of IT adoption decision making than existing frameworks and models. The framework offers a potentially valuable basis for future research in IT adoption decision making in organisations. The results suggest that the framework may facilitate IT adoption in organisations using different components.Information ScienceD. Litt. et Phil. (Information systems