re-ADA for C4ISR Sheldon X. Liang, PhD Computer Science

re-ADA for C4ISR Reliable Ada-based Descriptive Architecture via a Quantifiable Interoperating Model  Why re-ADA?  Scalable re-ADA  Formal re-ADA  A C4ISR Case Study  Practical re-ADA  Quantifiable re-ADA

The International Language for SE The Language for a Complex World The first ISO-standardized OOPL The Quantitative ADL for C4ISR re-ADA for C4ISR Why re-ADA?  Excellence and Drawbacks Why? Ada95 has the meaning of OOP but does not have the class-like form What an embarrassing – a C++ or Java programmer who has expertise in OOP may not be able to write code in Ada95

re-ADA for C4ISR Why re-ADA?  Expectations and Accomplishments OOPL Mean / Form Perfect OOPL Like Java/C++ Not just OOPL But ADL re-Ada Ada95 re-ADA

re-ADA for C4ISR Why re-ADA?  Approach against Drawbacks re-Ada Ada95 ISO OOPL re-ADA Class-like OODM C++/Java-like Class construct C++/Java-like Class construct CSP-based Semantics CSP-based Semantics CORBA-based Infrastructure CORBA-based Infrastructure Quantitatively Modeling Dependability (RT) Reliable Architecture for C4ISR Interoperability C4ISR

re-ADA for C4ISR Why re-ADA?  Quantitatively Modeling Interoperability Dependable Interoperability with respect to RT constraints can be monitored at runtime

re-ADA for C4ISR Scalable re-ADA  An Evolutionary Approach Interoperability for C4ISR Interoperability for C4ISR System Interoperability Information Interoperability Dependable Interoperation Effective Intercommunication Software Interoperability Seamless Interconnection

re-ADA for C4ISR Scalable re-ADA  An Evolutionary Approach re-ADA aims to enable legacy (heterogeneous) components to work together over the network by using interoperability technologies:  data unification,  message-sending, and  interoperable shell.

Seamless Interconnection re-ADA for C4ISR Scalable re-ADA  An Evolutionary Approach Software interoperability refers to inconsistent representation of the same real world entity in various legacy component systems. By data unification and OOMI (Object-Oriented Model for Interoperability), the heterogeneous legacy component can be abstracted as a coarser-grained object that is unified into a standard representation.

Seamless Interconnection Effective Intercommunication re-ADA for C4ISR Scalable re-ADA  An Evolutionary Approach For the sake of effective SMS/RMI between distributed components, a set of explicit functionalities needs to realize effective intercommunication. Information interoperability refers to two message-sending ways: Simple Message Sending (SMS) and Remote Method Invocation (RMI) via message-sending.

Seamless Interconnection Effective Intercommunication re-ADA for C4ISR Scalable re-ADA  An Evolutionary Approach

Seamless Interconnection Effective Intercommunication Dependable Interoperation re-ADA for C4ISR Scalable re-ADA  An Evolutionary Approach System interoperability refers to joint task execution over the network that is realized via message-sending in a dependable way Dependable Interoperability with respect to RT constraints can be monitored at runtime

re-ADA for C4ISR Scalable re-ADA  An Evolutionary Approach Interoperability for C4ISR Interoperability for C4ISR System Interoperability Information Interoperability Dependable Interoperation Effective Intercommunication Software Interoperability Seamless Interconnection

re-ADA for C4ISR Scalable re-ADA  An Evolutionary Approach

Formal dependability model re-ADA for C4ISR Formal re-ADA  Quantitative Interoperating Model Constructing formal dependability model for C4ISR the process that incorporates three views of dependability throughout software development process  Quantitative view  Conceptual view  Semantic view acquiring dependability requirements that refer to fundamental attributes: mapping attributes into measurable constraints binding attributes onto architectural artifacts, like the role, style, and protocol

Formal dependability model re-ADA for C4ISR Formal re-ADA  Quantitative Interoperating Model Constructing formal dependability model for C4ISR the process that incorporates three views of dependability throughout software development process  Quantitative view  Conceptual view  Semantic view

Formal dependability model re-ADA for C4ISR Formal re-ADA  Quantitative Interoperating Model Dependable Interoperation between two collaborative components in production-consumption (Prepare  Respond) pattern. Three kinds of timing constraints have been developed to reflect dependability attributes, such as availability or reliability:  MET (maximum execution time) for client side,  MRT (maximum response time) for server side, and  LATENCY (maximum delay during communication)

Formal dependability model re-ADA for C4ISR Formal re-ADA  Quantitative Interoperating Model Client/Publisher Server/Subscriber The client prepares message (constrained by MET), and sends it out as a RMI message (constrained by LATENCY), and then expects response from the server (constrained by MRT)

Formal dependability model re-ADA for C4ISR Formal re-ADA  Quantitative Interoperating Model

Formal dependability model Real-time constraints monitor re-ADA for C4ISR Formal re-ADA  Quantitative Interoperating Model In distributed computing environment, multi-threads dominate the interoperation between Publisher and Subscriber., and Agent that plays a role of Publisher that delivers message for response, and a role Subscriber that observes message by giving response. Real-time constraints can be monitored at runtime on the basis of multi-threading communication.

Formal dependability model Real-time constraints monitor re-ADA for C4ISR Formal re-ADA  Quantitative Interoperating Model (a) Preparation for delivering constrained by MET (b) Response for observing constrained by MRT (c) intercommunication constrained by LATENCY

Formal dependability model Real-time constraints monitor A C4ISR case study re-ADA for C4ISR Formal re-ADA  Quantitative Interoperating Model A C4ISR system is generally composed of component systems in military applications – for instance, airplanes in the sky, warships in the sea, submarines underwater or missiles on the land, all of which connects with the battle management infrastructure.

Formal dependability model Real-time constraints monitor A C4ISR case study re-ADA for C4ISR Formal re-ADA  Quantitative Interoperating Model Dependable interoperability makes a lot of sense with C4ISR in regards to the collaborative interoperation of military commands in a coalition. C4ISR is usually established on the military internetworking infrastructure (network-centric warfare).

re-ADA for C4ISR Formal re-ADA  A C4ISR Case Study

re-ADA for C4ISR Formal re-ADA  A C4ISR Case Study C4ISR architectures aim to improve capabilities by enabling the quick synthesis of “go-to-war” requirements with sound investments leading to the rapid employment of improved operational capabilities, and enabling the efficient engineering of warrior systems.

re-ADA for C4ISR Formal re-ADA  A C4ISR Case Study

Syntactic class construct re-ADA for C4ISR Practical re-ADA  Class-like OOP in Ada95 In re-ADA, all heterogeneous components are required to play a specific role -- either a Publisher or a Subscriber, or both. So we need an up-most ancestor class Role for defining generalized features for all descendant classes to inherit from, such as tagged, Controlled, Initialize and Finalize (Ada95/Ada05). In this Ada-based design approach, the pristine notion of class is introduced as a major program element in a package in support for more straightforward object-oriented construction; and through inheritance, many descendant classes can be derived.

Syntactic class construct re-ADA for C4ISR Practical re-ADA  Class-like OOP in Ada95 An Ada-based pristine class in an Ada package is treated as program unit that encloses properties (data & subprograms)

Syntactic class construct re-ADA for C4ISR Practical re-ADA  Class-like OOP in Ada95 There are five rules that have been developed as key points upon which a pre-compiler can be made to translate the pristine class into Ada95/Ada05 code.  R-1 class and type: a class name always implies two types;  R-2 member method: a member method is an access to a subprogram  R-3 constructor and destructor: They are Initialize and Finalize  R-4 prefix “Current” access within member method’s body:  R-5 object designator: “Obj<-” is introduced to to choose the member method.  R-6 Interoperation via Collaborator: a pair of publisher and subscriber will share a task that collaborates on the interoperation.  R-7 Concurrent computation and synchronous rendezvous: under the monitor of the collaborator, there are two tasks working for the publisher and the subscriber, respectively.

Syntactic class construct re-ADA for C4ISR Practical re-ADA  Class-like OOP in Ada95

Syntactic class construct Inheritance and polymorphism re-ADA for C4ISR Practical re-ADA  Class-like OOP in Ada95 The Collaborator’s connection provides a useful means by which a concrete component is assigned to play a specific role (Publisher or Subscriber). In terms of role-assignment, there are two ways to “glue” the concrete component on the specific role:  Object embedment, and  Object derivation. The object derivation is to derive a new class and override the existing member method (predefined by the framework) – for instance, procedure Prepare is abstract. An abstract member method represents polymorphism and dynamic binding.

Syntactic class construct Inheritance and polymorphism re-ADA for C4ISR Practical re-ADA  Class-like OOP in Ada95 Through inheritance, the subclass can redefine a subprogram by overriding it, which means polymorphism

Syntactic class construct Inheritance and polymorphism Computational collaboration re-ADA for C4ISR Practical re-ADA  Class-like OOP in Ada95 We now take a closer look at the C4ISR case study. Although we already have an outlined configuration with Ada-based descriptive architecture, here we apply the 6th rule and the 7th rule to translate the Ada-based description into real Ada95 code

re-ADA for C4ISR Practical re-ADA  Class-like OOP in Ada95  Computational collaboration Code and Semantics

C4ISR: Reliable Interoperability C4ISR architectures aim to improve capabilities by enabling the quick synthesis of “go-to-war” requirements, and enabling the efficient engineering of warrior systems QIM/re-ADA: Quantitatively Modeling Architecture The QIM/re-ADA provides the explicit loci around which designers are able to stress and evaluate the non-functional properties during architectural design. re-ADA/CORBA: Descriptive Architecture & Infrastructure re-ADA/CORBA maps dependability into quantifiable constraints as architectural (semantic) properties that are constructed on the basis of CORBA, so that dependable interoperation can be verified at runtime. re-ADA for C4ISR Quantifiable re-ADA  Conclusion

re-ADA for C4ISR Questions