A Type-Safe Model of Adaptive Object Groups

Services are autonomous, self-describing, technology-neutral software units that can be described, published, discovered, and composed into software applications at runtime. Designing software services and composing services in order to form applications or composite services requires abstractions beyond those found in typical object-oriented programming languages. This paper explores service-oriented abstractions such as service adaptation, discovery, and querying in an object-oriented setting. We develop a formal model of adaptive object-oriented groups which offer services to their environment. These groups fit directly into the object-oriented paradigm in the sense that they can be dynamically created, they have an identity, and they can receive method calls. In contrast to objects, groups are not used for structuring code. A group exports its services through interfaces and relies on objects to implement these services. Objects may join or leave different groups. Groups may dynamically export new interfaces, they support service discovery, and they can be queried at runtime for the interfaces they support. We define an operational semantics and a static type system for this model of adaptive object groups, and show that well-typed programs do not cause method-not-understood errors at runtime.Comment: In Proceedings FOCLASA 2012, arXiv:1208.432

Composing concurrent objects

Adopting the object-oriented paradigm for the development of large and complex software systems offers several advantages, of which increased extensibility and reusability are the most prominent ones. The object-oriented model is also quite suitable for modelling concurrent systems. However, it appears that extensibility and reusability of concurrent applications is far from trivial. In addition, very little attention has been paid by the conventional object-oriented development methodologies to the analysis and design of\ud synchronisation constraints for concurrent objects.\ud To address these problems, in this thesis the framework of composition-filters, an extension to the object-oriented model, is adopted. An analysis is presented of the problems involved in reusing and extending concurrent objects, in particular the so-called inheritance anomalies. Based on this analysis, a set of criteria for effective extensible concurrent objectoriented\ud programming languages is formulated.\ud The thesis introduces techniques for the creation of concurrency and the synchronisation of concurrent activities, fully integrated within the (object-oriented) composition-filters model. Important properties of the proposed object model are: all objects are -potentially- active, intra-object concurrency is supported and synchronisation specifications are fully separated\ud from method implementations. The applicability and expressive power of the proposed technique are demonstrated, and it is shown how reusability and extensibility of concurrent objects are achieved

Towards Multi-class Object Detection in Unconstrained Remote Sensing Imagery

Automatic multi-class object detection in remote sensing images in unconstrained scenarios is of high interest for several applications including traffic monitoring and disaster management. The huge variation in object scale, orientation, category, and complex backgrounds, as well as the different camera sensors pose great challenges for current algorithms. In this work, we propose a new method consisting of a novel joint image cascade and feature pyramid network with multi-size convolution kernels to extract multi-scale strong and weak semantic features. These features are fed into rotation-based region proposal and region of interest networks to produce object detections. Finally, rotational non-maximum suppression is applied to remove redundant detections. During training, we minimize joint horizontal and oriented bounding box loss functions, as well as a novel loss that enforces oriented boxes to be rectangular. Our method achieves 68.16% mAP on horizontal and 72.45% mAP on oriented bounding box detection tasks on the challenging DOTA dataset, outperforming all published methods by a large margin (+6% and +12% absolute improvement, respectively). Furthermore, it generalizes to two other datasets, NWPU VHR-10 and UCAS-AOD, and achieves competitive results with the baselines even when trained on DOTA. Our method can be deployed in multi-class object detection applications, regardless of the image and object scales and orientations, making it a great choice for unconstrained aerial and satellite imagery.Comment: ACCV 201

Object-oriented construction of a multigrid electronic-structure code with Fortran 90

We describe the object-oriented implementation of a higher-order finite-difference density-functional code in Fortran 90. Object-oriented models of grid and related objects are constructed and employed for the implementation of an efficient one-way multigrid method we have recently proposed for the density-functional electronic-structure calculations. Detailed analysis of performance and strategy of the one-way multigrid scheme will be presented.Comment: 24 pages, 6 figures, to appear in Comput. Phys. Com

Improving the reuse possibilities of the behavioral aspects of object-oriented domain models.

Reuse of domain models is often limited to the reuse of the structural aspects of the domain (e.g. by means of generic data models). In object-oriented models, reuse of dynamic aspects is achieved by reusing the methods of domain classes. Because in the object-oriented approach any behavior is attached to a class, it is impossible to reuse behavior without at the same time reusing the class. In addition, because of the message passing paradigm, object interaction must be specified as a method attached to one class which is invoked by another class. In this way object interaction is hidden in the behavioral aspects of classes. This makes object interaction schemas difficult to reuse and customize. The focus of this paper is on improving the reuse of object-oriented domain models. This is achieved by centering the behavioral aspects around the concept of business events.Model; Models;

A theorem prover-based analysis tool for object-oriented databases

We present a theorem-prover based analysis tool for object-oriented database systems with integrity constraints. Object-oriented database specifications are mapped to higher-order logic (HOL). This allows us to reason about the semantics of database operations using a mechanical theorem prover such as Isabelle or PVS. The tool can be used to verify various semantics requirements of the schema (such as transaction safety, compensation, and commutativity) to support the advanced transaction models used in workflow and cooperative work. We give an example of method safety analysis for the generic structure editing operations of a cooperative authoring system

A Software-Defined Radio Simulation Method using Observer Patterns

A problem with object-oriented simulation models is that internal model states are hidden and cannot be monitored easily. Object-oriented models are essentially black-box models. This article describes a method to expose the internal states of an object-oriented simulation model. Exposure of the states is achieved though application of the Observer software pattern in the form of data sources. Data sources can be connected to a data sink which then receives data from the sources. Connections between data sources and sinks are made though a broker. The globally accessible broker holds information on the available data sources. Some implementation details of a simulation framework\ud based around the method are discussed. The framework is tested using a small simulation example on I/Q imbalance. Although the focus is on software-defined radio and communication systems, the concepts presented here can also be applied to other types of object-oriented simulation

Advanced software development workstation. Comparison of two object-oriented development methodologies

This report is an attempt to clarify some of the concerns raised about the OMT method, specifically that OMT is weaker than the Booch method in a few key areas. This interim report specifically addresses the following issues: (1) is OMT object-oriented or only data-driven?; (2) can OMT be used as a front-end to implementation in C++?; (3) the inheritance concept in OMT is in contradiction with the 'pure and real' inheritance concept found in object-oriented (OO) design; (4) low support for software life-cycle issues, for project and risk management; (5) uselessness of functional modeling for the ROSE project; and (6) problems with event-driven and simulation systems. The conclusion of this report is that both Booch's method and Rumbaugh's method are good OO methods, each with strengths and weaknesses in different areas of the development process