Abstract.

In this paper we present a new approach to data modelling, called the concept-oriented model (CoM), and describe its main features and characteristics including data semantics and operations. The distinguishing feature of this model is that it is based on the formalism of nested ordered sets where any element participates in two structures simultaneously: hierarchical (nested) and multi-dimensional (ordered). An element of the model is postulated to consist of two parts, called identity and entity, and the whole approach can be naturally broken into two branches: identity modelling and entity modelling. We also propose a new query language with the main construct, called concept, defined as a pair of two classes: identity class and entity class. We describe how its operations of projection, de-projection and product can be used to solve typical data modelling tasks.

Table of contents:

• 1. Introduction
• 2. Nested Ordered Sets
• 3. Data Semantics and Operations
• 4. Concept-Oriented Query Language
• 5. Related Work
• 6. Conclusions

Abstract.

In the paper we introduce a new programming language construct, called concept, which is defined as a pair of two classes: one reference class and one object class. Instances of the reference class are passed-by-value and are intended to indirectly represent objects. Instances of the object class are passed-by-reference. Each concept has a parent concept specified by means of the concept inclusion relation. This approach where concepts are used instead of classes is referred to as concept-oriented programming (CoP). CoP is intended to generalize object-oriented programming (OOP). Particularly, concepts generalize conventional classes and concept inclusion generalizes class inheritance in OOP. This approach allows the programmer to describe not only objects but also references which are made integral and completely legal part of the program. Program objects at run-time exist within a virtual hierarchal address space and CoP provides means to effectively design such a space for each concrete problem domain.

Table of contents:

• 1. Introduction
• 2. Concept Definition
• 3. Concept Inclusion
• 4. Other Mechanisms
• 5. Related Work
• 6. Conclusions

A. Savinov, Informal Introduction into the Concept-Oriented Programming

Abstract.

This paper describes a new approach to programming, called the concept-oriented programming (CoP). It is based on using a new programming construct, called concept, which generalizes conventional classes. Concepts describe behaviour of both objects and references. Hence references are completely legalized and made first-class citizens with the same rights as objects. Using concepts the programmer can easily describe custom virtual address spaces where objects will exist. The hierarchical structure of such a space is modelled by means of concept inclusion relation which generalizes class inheritance. In CoP, a great deal or even most of functions are executed implicitly during object access rather than in target objects themselves. These functions have cross-cutting nature but can be effectively separated using CoP.

Table of contents:

• 1. Introduction
• 2. Hierarchical Addresses
• 3. References and Objects
• 4. From Classes to Concepts
• 5. Access via Dual Methods
• 6. CoP vs. OOP
• 7. CoP vs. AOP
• 8. Concept-Oriented Model
• 9. Conclusions

A. Savinov, Two-Level Concept-Oriented Data Model, Technical Report RT 0006, Institute of Mathematics and Computer Science, Academy of Sciences of Moldova, 2007

Abstract.

In this paper we describe a new approach to data modelling called the concept-oriented model (CoM). This model is based on the formalism of nested ordered sets which uses inclusion relation to produce hierarchical structure of sets and ordering relation to produce multi-dimensional structure among its elements. Nested ordered set is defined as an ordered set where an each element can be itself an ordered set. Ordering relation in CoM is used to define data semantics and operations with data such as projection and de-projection. This data model can be applied to very different problems and the paper describes some its uses such grouping with aggregation and multi-dimensional analysis.

A. Savinov, An Approach to Programming Based on Concepts, Technical Report RT 0005, Institute of Mathematics and Computer Science, Academy of Sciences of Moldova, 2007

Abstract.

In this paper we describe a new approach to programming which generalizes object-oriented programming. It is based on using a new programming construct, called concept, which generalizes classes. Concept is defined as a pair of two classes: one reference class and one object class. Each concept has a parent concept which is specified using inclusion relation generalizing inheritance. We describe several important mechanisms such as reference resolution, context stack, dual methods and life-cycle management, inheritance and polymorphism. This approach to programming is positioned as a new programming paradigm and therefore we formulate its main principles and rules.

A. Savinov, Concepts and their Use for Modelling Objects and References in Programming Languages, Technical Report RT 0004, Institute of Mathematics and Computer Science, Academy of Sciences of Moldova, 2007.

Abstract.

In the paper a new programming construct, called concept, is introduced. Concept is pair of two classes: a reference class and an object class. Instances of the reference classes are passed-by-value and are intended to represent objects. Instances of the object class are passed-by-reference. An approach to programming where concepts are used instead of classes is called concept-oriented programming (CoP). In CoP objects are represented and accessed indirectly by means of references. The structure of concepts describes a hierarchical space with a virtual address system. The paper describes this new approach to programming including such mechanisms as reference resolution, complex references, method interception, dual methods, life-cycle management inheritance and polymorphism.

A. Savinov, Query by Constraint Propagation in the Concept-Oriented Data Model, Computer Science Journal of Moldova, Vol. 14, No. 2, 219-238, 2006

Abstract. The paper describes an approach to query processing in the concept-oriented data model. This approach is based on imposing constraints and specifying the result type. The constraints are then automatically propagated over the model and the result contains all related data items. The simplest constraint propagation strategy consists of two steps: propagating down to the most specific level using de- projection and propagating up to the target concept using projection. A more complex strategy described in the paper may consist of many de-projection/projection steps passing through some intermediate concepts. An advantage of the described query mechanism is that it does not need any join conditions because it uses the structure of the model for propagation. Moreover, this mechanism does not require specifying an access path using dimension names. Thus even rather complex queries can be expressed in simple and natural form because they are expressed by specifying what information is available and what related data we want to get.

A. Savinov, Indirect Object Representation and Access by Means of Concepts Institute of Mathematics and Informatics, Academy of Sciences of Moldova, Technical Report, 8pp., September 2006

Abstract. The paper describes a mechanism for indirect object representation and access (ORA) in programming languages. The mechanism is based on using a new programming construct which is referred to as concept. Concept consists of one object class and one reference class both having their fields and methods. The object class is the conventional class as defined in OOP with instances passed by reference. Instances of the reference class are passed by value and are intended to represent objects. The reference classes are used to describe how objects have to be represented and accessed by providing custom format for their identifiers and custom access procedures. Such an approach to programming where concepts are used instead of classes is referred to as concept-oriented programming. It generalizes OOP and its main advantage is that it allows the programmer to describe not only the functionality of target objects but also intermediate functions which are executed behind the scenes as an object is being accessed.

A. Savinov, Grouping and Aggregation in the Concept-Oriented Data Model, Proc. ACM Symposium on Applied Computing (SAC 2006), April 23-27, 2006, Dijon, France, 482-486

Abstract. In the paper we describe the problem of grouping and aggregation in the concept-oriented data model. The model is based on ordering its elements within a hierarchical multidimensional space. This order is then used to define all its main properties and mechanisms. In particular, it is assumed that elements positioned higher are interpreted as groups for their lower level elements. Two operations of projection and de-projection are defined for one-dimensional and multidimensional cases. It is demonstrated how these operations can be used for multidimensional analysis.

More information on these and other concept-oriented technologies can be found on the concept-oriented portal. In particular, questions on these next generation technologies can be asked on the recently opened forum.

CoP is part of the new concept-oriented paradigm which includes also the concept-oriented data model (CoM). If the concept-oriented data model describes the meaning of objects and how we can manipulate it, then CoP is intended to describe object identification mechanism, i.e., how objects are represented and accessed. Both they provide a very expressive and powerful framework for describing complex systems. More information on these and other concept-oriented technologies can be found on the concept-oriented portal. In particular, questions on these next generation technologies can be asked on the recently opened forum.

A. Savinov, Concept as a Generalization of Class and Principles of the Concept-Oriented Programming, Computer Science Journal of Moldova 13(3), 292-335, 2005.

Abstract. In the paper we describe a new construct which is referred to as concept and a new concept-oriented approach to programming. Concept generalizes conventional classes and consists of two parts: an objects class and a reference class. Each concept has a parent concept specified via inclusion relation. Instances of reference class are passed by value and are intended to represent instances of child object classes. The main role of concepts consists in indirecting object representation and access. In concept-oriented programming it is assumed that a system consists of (i) conventional target business methods (BMs), and (ii) hidden representation and access (RA) methods. If conventional classes are used to describe only BMs then concepts allow the programmer to describe both types of functionality including its hidden intermediate functions which are automatically executed when objects are being accessed.

The new forum is aimed at discussing all problems concerning the concept-oriented paradigm. In particular, one can ask and discuss any questions on the concept-oriented data model and concept-oriented programming, advantages and disadvantages of these next generation technologies, their properties, how they relate to other approaches and open issues.

A. Savinov, Hierarchical Multidimensional Modelling in the Concept-Oriented Data Model, Proc. the 3rd international conference on Concept Lattices and Their Applications (CLA'05), Olomouc, Czech Republic, September 7-9, 2005, 123-134.

Abstract. In the paper the concept-oriented data model (COM) is described from the point of view of its hierarchical and multidimensional properties. The model consists of two levels: syntactic and semantic. At the syntactic level each element is defined as a combination of its superconcepts. At the semantic level each item is defined as a combination of its superitems. Such a definition has several general interpretations such as a hierarchical coordinate system or multidimensional categorization schema. The described approach can be applied to very different problems for dimensional modelling including database systems, knowledge based systems, ontologies, complex categorizations, knowledge sharing and semantics web.

• Principles and Goals
• Multidimensional Hierarchical Schema
• Modelling Relationships
• Inverse Dimensions and Access Path
• Query Language
• Conclusions