Emerging challenges and frontiers in cloud computing

Cloud computing has become an exciting platform in modern IT era that provides on-demand services and resources such as compute power, memory, storage, networking, and various software services. A large number of small and medium size companies and big organizations have been exploiting cloud computing services for various applications in order to save time and cost as they do not have to maintain their own IT infrastructure. Cloud computing has various benefits such as flexibility, scalability, automatic maintenance of software, and anywhere and anytime service provisioning over the Internet.1 This special issue was organized to solicit papers via an open call as well as selected papers from the IEEE 4th International Conference on Future Internet of Things and Cloud (FiCloud 2016) and the 13th International Conference on Mobile Web and Intelligent Information Systems (MobiWis 2016), which were held in Vienna, Austria, 22-24 August 2016. The conferences were attended by a large number of participants from different countries across the world. The conferences featured a number of technical sessions of research papers, industry talks, and keynote talks. A number of workshops and symposia were also organized alongside the FiCloud and MobiWis conferences. This special issue focused on the emerging challenges and frontiers in cloud computing. The objective of this special issue is to showcase the most recent developments and research in the area of cloud computing such as cloud models and architectures, eg, Software as a Service (SaaS), Software-defined network (SDN), security in cloud computing, mobile cloud, cloud networking, and communication and cloud REST services. A number of papers were submitted to this special issue. Each of the paper was reviewed by multiple reviewers. Based on the reviews, eight papers were accepted for this special issue. The work presented in these papers is summarized as follows. Stavrinides and Karatza2 carry out investigations into the challenges involved in Software as a Service cloud computing. These challenges are mainly due to heterogeneity and multi-tenancy in the host environment. Authors argue that according to the Service Level Agreement (SLA) between the cloud providers and the end-users, the execution of applications must be time constrained. It has been claimed that the effective scheduling of multiple parallel applications is one of the most important aspects of SaaS in order to avoid any violation of SLA. Their work focuses on the enhancement of the most commonly used scheduling algorithms by utilizing approximate computation and evaluating the impact of the computational demand variability on the performance of the employed scheduling strategies. The simulated-based experimental results give a very interesting insight. One of the main objectives of Software-Defined Networking (SDN) is to enable cloud computing to be flexible and agile in order to support virtualized servers and data storage infrastructure of the data centers. Benkhelifa et al3 underpin a very interesting issue of combining mobile computing with cloud computing. The basic idea in this research is to create a cloud-computing environment by exploiting localized mobile devices. Through application of social models, they claim that the mobile devices can employ cooperative strategies for effective sharing of resources. They propose the design of a system that employs aggregated user and application resource profiling. This determines the optimal place for data processing and leads to finding a balance between optimum energy consumption and efficient resource utilization. Vinh et al4 investigate the security aspects of mobile cloud computing. One of the key challenges highlighted in this work is the assurance of trust on mobile devices, which play a key role in mobile cloud computing. Mobile device attestation has been recognized as a way to tackle this problem. The main contribution presented in this paper includes the property-based token attestation (PTA), which takes the advantage of existing techniques, such as Trusted Platform Module (TPM), Bring Your Own Device (BYOD), etc, to secure the mobile devices. A detailed analysis of the security threats has been included. This is followed by the proposed attestation schema for tackling these threats. Omezzine et al5 highlight the complexity of a cloud operational environment where the application providers want to maximize their profit and the end user demands high quality efficient application provisioning. The significance of negotiation has been addressed as a way forward to satisfy both service providers and service users. Two of the main characteristics of cloud application provisioning, which have been identified in this work, have been neglected in the current negotiation models. This work addresses both these properties and proposes a multi-layered negotiation framework that includes a generic negotiation model for cloud provisioning. The paper also presents an instantiation among cloud layers for efficient SaaS provisioning to demonstrate maximization of provider profit and increased satisfaction of users. Simulation-based experiments using multi-agent system technology demonstrate that negotiation improves the application provisioning in terms of profit for the SaaS provider and in terms of user satisfaction. Bull et al6 investigate the performance of periodic data flows on the real SDN hardware in a variety of situations. The work uses a Preemptive Flow Installation Mechanism (PFIM) to improve SDN performance for periodic traffic by limiting the number of controller look-ups through predicting when a flow is likely to need a particular rule. The experimental results demonstrate that the system can detect the majority of temporary periodic flows and preemptively install a flow rule, facilitating performance comparable to layer two switching speeds. Kim et al7 investigated the transmission of data in IoT devices using Low Power Wide Area Network (LPWAN), which is managed by a centralized server in the cloud. Their research highlights the vulnerability of the server in terms of response time and bandwidth utilization. To address this issue, the authors have proposed an interesting approach to move the control of LPWAN to the edge cloud. In the proposed approach, an LPWAN gateway is integrated with the edge cloud and LPWAN data is cached at the edge cloud in the gateway for LPWAN control. The proposed approach has demonstrated performance gains over the existing approaches and improves the data transmission response time while enhancing the bandwidth utilization. Khosrowshahi-Asl et al8 investigate a very complex issue of forming communities of identical or complementary cloud services for better visibility and efficiency. Contrary to most of the existing models, which require real-time global knowledge of services, this work proposes an efficient yet computationally cost-effective model based on partially available information to form communities. The proposed strategic Distributed Decision-making Mechanism (DDM) regulates the cloud services decision-making process. DDM generates an initial set of data based on information obtained from existing cloud services regarding their single and cooperative efficiency. This is then analyzed based on the distance function followed by the implementation of communities formation. The experimental results clearly indicate the performance gains over the existing solution. Mesfin et al9 work underpins an interesting framework of the REST services development for smartphones. The main objective of this work is to enhance the usability of composing services on smartphones. This work employed the design science research methodology to describe the new framework, REST4Mobile. The framework's usability evaluation is conducted using a systems usability scale. The evaluation results reveal that the guidelines in the REST4Mobile framework can enhance usability of REST services on smartphones. This encourages further studies on design approaches for enterprise level mobile end-users. The papers presented in this special issue are related to the emerging topics in cloud computing. The topics covered in this collection include scheduling, security, formation of community, service negotiation, and Data control, among others. We hope the readers will benefit from the research findings included in this special issue. Irfan Awan is a Professor of Computer Science at the University of Bradford. His research focuses on Network Security, Cyber Security, Performance Modeling of Cloud, and Communication Networks. His research work won Best Paper Awards from 24th IEEE AINA 2010, Australia and 8th BWCCA 2013, France. His research work has been published in IEEE Transactions, IEE Proceedings, IEEE Computer Magazine, among others. He is a member of editorial board of the Elsevier journal of Simulation, Modeling and Practice and served as a guest editor for various special issues. Professor Awan organized and chaired several international conference and workshops and edited proceedings. He has successfully supervised 34 Ph.D. students. Professor Awan is a fellow of HEA, fellow of BCS, and member IEEE. Muhammad Younas is a Reader in Computer Science at the School of Engineering, Computing and Mathematics, Oxford Brookes University, UK. His research interests include Web technologies, cloud and services computing, and Big data. He received a Ph.D. in Computer Science from the University of Sheffield, UK. He has published more than hundred papers in international journals and conferences. He is on the editorial and advisory boards of international journals and is also involved in the steering, organizing, and program committees of refereed international conferences and workshops. Farookh Khadeer is Associate Professor at the School of Computer Science, University of Technology, Sydney, Australia. He received the B.Tech. degree in Computer Science and Computer Engineering and the M.S. degree in Information Technology from the La Trobe University, Melbourne, Australia, and the Ph.D. degree in Information Systems from Curtin University of Technology, Perth, Australia, in 2006. His areas of active research are cloud computing, services computing, trust and reputation modeling, semantic web technologies, and industrial informatics. He works actively in the domain of cloud computing and business intelligence. In the area of business intelligence, the focus of his research is to develop smart technological measures such as trust and reputation technologies and semantic web for enhanced and accurate decision making. We would like to express our special thanks to all authors who contributed to this special issue. We are also very thankful to all reviewers for participating in a rigorous review process and providing useful feedback to authors to enhance their work. Finally, we would like to express our special gratitude to Professor Geoffrey Fox, the Editor-in-Chief, for providing us with this unique opportunity to present state-of-the-art research work in a special issue of the international journal of Concurrency and Computation: Practice and Experience.