Amit Kr Mandal

A Novel and Flexible Cloud Architecture for Data-Centric Applications

Software as a service or (SaaS) is a new software development and deployment paradigm over the cloud. It offers Information Technology services dynamically as “on-demand” basis over the internet. The related application data are stored in the large data centers managed by the Cloud Service Providers. Therefore the user need not to bother about the data storage or data management techniques and they can be able to access their applications from anywhere on the globe via a standard web browser. Many enterprises are facing a major research challenge due to the unavailability of generic cloud architecture for designing, developing and deploying of cloud services. In this paper flexible cloud architecture has been proposed, specifically for data centric applications which are suitable for heterogeneous types of applications. This paper also has aimed to establish the future research agendas related to design and management of data centric applications over the cloud infrastructure.

Flexible Cloud Architecture for Healthcare Applications

A healthcare cloud is used by healthcare service providers for storing, maintaining, and backing up personal health information along with structured management of the health data across multiple healthcare providers. On a daily basis, healthcare services deal with different kinds of digital information ranging from structured to unstructured. The widespread adoption of electronic health records have resulted in an improved patient health and safety as well as significant savings in healthcare costs. Moreover, deploying healthcare records over cloud environment will enable access of critical patient’s information at any time and from anywhere. But many enterprises are facing a major research challenge due to the unavailability of suitable cloud architecture for design, development, and deployment of healthcare services. In this paper, a flexible architecture for SaaS-based healthcare services has been proposed specifically for healthcare applications, which is capable of semi-structured healthcare data management and storing compatible with Health Level Seven (HL7) standard (Hennessy et al. in A framework and ontology for mobile sensor platforms in home health management, 2013; Liu et al. in iSMART: ontology-based semantic query of CDA documents AMIA annual symposium, pp. 375–379, 2009) [6, 7]. HL7 specifies the structure and semantics of “clinical documents” for the purpose of sharing; therefore, data can be easily shared among the applications.

Modelling of business processes for software as a service

The traditional approach to business process modelling frequently results in large models that are difficult to change and maintain. In cloud-based environment, business dynamics are mandating that business processes normally be increasingly responsive to changes. This demands business process should be highly modular, scalable and flexible for cloud-based applications. Further, in cloud-based business environments, besides describing new capabilities, process models should also define how those capabilities can be integrated with the existing systems. In this paper, a hierarchical graph-based specification called business component graph for SaaS (BCGS) has been proposed to address those issues. The proposed BCGS, formally, realises the business components for software as a service (SaaS)-based applications. BCGS represents the complex business logic design as a set of business components and their inter-relationships. Here, business component is defined as methodical integration of business processes and business rules. This proposed integration approach facilitates high scalability and reusability of constituent elements of business components and ensures the consistency between processes and business rules. Moreover, this paper also includes the service orientation of the proposed concepts in SaaS framework. A detailed case study of BCGS also has been illustrated to show the expressiveness of the proposed concepts.

Service Oriented System design: Domain Specific Model based approach

Several design specifications of service oriented architecture (SOA) reflects that traceability is a desired feature among business process model and service based implementation. But most of the literatures have merely drawn any suitable correspondence between business process facets and service concepts for service based system design. This paper proposes a Domain Specific Model based approach for designing and development of Service Oriented System (SOS) to reduce the semantic gap between business process and corresponding service representation. For the purpose, firstly, the domain level concepts of SOS are defined from both business process and service representation perspectives. Moreover, a set of traceability rules are devised to draw the correspondence between the business process and service domain concepts of SOS. Further the proposed modelling concepts have been implemented using Generic Modelling Environment (GME) [13] to generate the instance of SOS model in Web Service Description Language (WSDL) and corresponding process description based on Business Process Modelling Notation (BPMN). The expressiveness of the proposed SOS model has been illustrated using suitable case study.

Interface driven service composition: A highlevel colored PetriNet based approach

Service composition refers to the process of developing the complex services from existing services. In order to add or remove functionalities of the composite services and to reduce the human intervention, the service composition process should be dynamic, scalable, and reusable. For the purpose, this paper proposes a Colored PetriNet based approach for service composition. In the proposed mechanism, firstly, a conceptual model of service interface has been devised. Based on the conceptual model a Colored PetriNet (CPN) based model, called Colored PetriNet for Service Composition (CPSC) has been proposed to represent the behavioral aspects of the conceptual constructs of service interfaces and different composition aspects of the constituent services. It also implements a service composition algorithm to execute the composition sequence of services. Moreover, the proposed CPSC along with the algorithm are illustrated with a suitable case study and simulated using CPN tool. The result shows that the proposed algorithm can successfully compose services based on the user requirements. Beside these, the state space report of the proposed CPSC validates the standard behavioral properties of the concerned system.

Context driven metadata representation for SaaS

Metadata enables organizations or individuals to create and associated data that can help to define richer details about the world and events around it. For the cloud environment, metadata demands identification of associative capacity of information. At the same time, the system should be flexible, scalable and capable of supporting efficient searching mechanism over disparate information generated from varied contextual background. For the purpose, this paper proposes a conceptual model for context driven indexing system which is suitable for metadata representation of Software as a Service (SaaS) layers information of cloud environment. At the logical level, the proposed model is represented using a multidimensional tree structure and its equivalent XML document. Moreover, a set of operations has been defined on the proposed indexing system to perform the context based metadata refinement and searching operations. The expressive power of the proposed concept is illustrated using a case study of simplified electronic health record (EHR) system.

Interface driven service discovery: Colored Petri-Net based approach

Service discovery is the process of locating suitable services and retrieve their descriptions in response to the user requirements. The discovery process should include functional, behavioral and executional semantics of the services towards dynamic integration with users applications. However, most of the discovery approaches exist in the literature primarily relies only on functional aspects and data formats of the services. To address these issues, this paper proposes an interface driven service discovery mechanism. For this purpose, a conceptual model of service interfaces is proposed to express the related functional and behavioral facets based on which services are discovered. Further, a service interface behavioral model called, Colored Petri Net for Service Interface (CPSI), is also proposed to represent the conceptual constructs of service interfaces and behavioral aspects of related services. It also implements a two staged service discovery algorithm to find the target service and to integrate with the interface dynamically. The proposed CPSI and service discovery algorithm is simulated using the CPN tool. Further, the expressiveness of the proposed mechanism is illustrated using a suitable case study.

Formal representation of service interactions for SaaS based applications

Conceptualization of different aspects of cloud applications and formal representations of interactions among the different components of SaaS are most crucial issues towards the design of an effective cloud architectural framework. In this paper a graph-based specification called Cloud Service Architecture Graph (CSAG) has been proposed to model such interactions among various components of Software as a Service (SaaS). CSAG is capable of addressing several important aspects like extendibility, composability, analyzability etc. for SaaS based applications over cloud environment. Moreover, several properties of CSAG shows that the proposed approach is effective towards the design of a SaaS based applications. The proposed CSAG has been illustrated using the case study of Electronic Health Record (EHR) system over cloud environment.