• Journal of Broadcast Engineering
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• v.24 no.7
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• pp.1259-1265
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• 2019

Maintaining timing relationships among packets in a single media stream or between packets from different media streams is an essential criterion in MMT system. It is the function of the synchronization and de-jittering algorithms to re-adjust timing relationship between the MMT packets to assure synchronized playback. Thus, delivery of time constrained MPEG media on time, according to their temporal requirements, is an important goal of MMT. For this purpose MMT needs to specify syntax and semantics of a timing model to be used by the delivery functions. In this paper, we propose a proper timestamp-related header format for MMT delivery timing model to support media synchronization in various delivery scenarios including hybrid delivery.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.2 no.1
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• pp.26-32
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• 2002

The objectives of this paper are twofold. First is to introduce a model for representing documents with semantics relatedness using rough sets but with tolerance relations instead of equivalence relations (TRSM). Second is to introduce two document hierarchical and nonhierarchical clustering algorithms based on this model and TRSM cluster-based information retrieval using these two algorithms. The experimental results show that TRSM offers an alterative approach to text clustering and information retrieval.

• Journal of the Korea Society for Simulation
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• v.21 no.2
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• pp.19-30
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• 2012

In recent decades, it has been known that the Discrete Event System Specification, or DEVS, formalism provides sound semantics to design a modular and hierarchical model of a discrete event system. In spite of this benefit, practitioners have difficulties in applying the semantics to real-world systems modeling because DEVS needs to specify a large size of sets of events and/or states in an unstructured form. To resolve the difficulties, this paper proposes an extension of the DEVS formalism, called the Structured DEVS formalism, with an associated graphical representation, called the DEVS diagram, by means of structural representation of such sets based on closure property of set theory. The proposed formalism is proved to be equivalent to the original DEVS formalism in their model specification, yet the new formalism specifies sets in a structured form with a concept of phases, variables and ports. A simplified example of the structured DEVS with the DEVS diagram shows the effectiveness of the proposed formalism which can be easily implemented in an objected-oriented simulation environment.

• Journal of Internet Computing and Services
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• v.11 no.4
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• pp.107-117
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• 2010

The feature models representing the common and variable concepts among the software products and the feature configurations generated by selecting the features to be included in the target product are the essential components in the software product lines methodology. Although the researches on the formal semantics and reasoning of the feature models and feature configurations are in progress, the researches on feature model ontologies and feature configuration validation using the semantic web technologies are yet insufficient. This paper defines the formal semantics of the feature models and proposes a feature configuration validation technique based on ontology and semantic web technologies. OWL(Web Ontology Language), a semantic web standard language, is used to represent the knowledge in the feature models and the feature configurations. SWRL(Semantic Web Rule Language), a semantic web rule languages, is used to define the rules to validate the feature configurations. The approach in this paper provides the formal semantic of the feature models, automates the validation of feature configurations, and enables the application of various semantic web technologies, such as SQWRL.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.12
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• pp.1-12
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• 1998

In this paper, a design and implementation of VHDL-to-C mapping in the VHDL compiler back-end is described. The analyzed data in an intermediate format(IF), produced by the compiler front-end, is transformed into a C-code model of VHDL semantics by the VHDL-to-C mapper. The C-code model for VHDL semantics is based on a functional template, including declaration, elaboration, initialization and execution parts. The mapping is carried out by utilizing C mapping templates of 129 types classified by mapping units and functional semantics, and iterative algorithms, which are combined with terminal information, to produce C codes. In order to generate the C program, the C codes are output to the functional template either directly or by combining the higher mapping result with intermediate mapping codes in the data queue. In experiments, it is shown that the VHDL-to-C mapper could completely deal with the VHDL analyzed programs from the compiler front-end, which deal with about 96% of major VHDL syntactic programs in the Validation Suite. As for the performance, it is found that the code size of VHDL-to-C is less than that of interpreter and worse than direct code compiler of which generated code is increased more rapidly with the size of VHDL design, and that the VHDL-to-C timing overhead is needed to be improved by the optimized implementation of mapping mechanism.

• The KIPS Transactions:PartD
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• v.9D no.3
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• pp.365-380
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• 2002

Temporal data mining, the incorporation of temporal semantics to existing data mining techniques, refers to a set of techniques for discovering implicit and useful temporal knowledge from large quantities of temporal data. Temporal knowledge, expressible in the form of rules, is knowledge with temporal semantics and relationships, such as cyclic pattern, calendric pattern, trends, etc. There are many examples of temporal data, including patient histories, purchaser histories, and web log that it can discover useful temporal knowledge from. Many studies on data mining have been pursued and some of them have involved issues of temporal data mining for discovering temporal knowledge from temporal data, such as sequential pattern, similar time sequence, cyclic and temporal association rules, etc. However, all of the works treated data in database at best as data series in chronological order and did not consider temporal semantics and temporal relationships containing data. In order to solve this problem, we propose a theoretical framework for temporal data mining. This paper surveys the work to date and explores the issues involved in temporal data mining. We then define a model for temporal data mining and suggest SQL-like mining language with ability to express the task of temporal mining and show architecture of temporal mining system.

• Knowledge Management Research
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• v.7 no.2
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• pp.53-68
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• 2006

Knowledge has become an important resource for organization. The manufacturing industry is usually operated on the basis of business processes, and most workers are familiar with their own processes. The process-based approach, therefore, can provide an efficient way to capture and navigate knowledge. In this study, we focus on knowledge which may be missed during knowledge transfer among workers. For this, we propose a method for analyzing knowledge flow, which is passed among business processes. We propose a process-based knowledge management framework for analyzing knowledge flow, which employs a two-phase analysis: process analysis and knowledge flow analysis. A knowledge flow model, represented by Knowledge Flow Diagram, is proposed as a tool for representing knowledge. We formulate several semantics for knowledge flow modeling. We build the three-level schema: conceptual, logical, and physical in order to automate the knowledge model adaptive to knowledge management systems. The proposed approach is verified and illustrated through a case study on the manufacturing process of A Company.

• Proceedings of the Korean Information Science Society Conference
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• 2008.06a
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• pp.55-59
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• 2008

In the field of software reuse, several methods for storage and retrieval of assets abound. However, these methods often find their limits; they fail to turn up the suitable reusable assets that satisfy the needs of a particular software system under development. Two problems are the root cause of this situation. One is the lack of accurate semantics for describing software assets. The other is the ignorance of the user query context. In such a context, this paper presents an XML-based asset representation model for describing all kinds of software asset that can be reused within software development process. The proposed model provides semantic metadata for describing assets oriented user context in order to build the foundation for semantic reasoning in the retrieval process.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.6
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• pp.197-202
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• 2019

XML has been established as a de facto standard for representing and exchanging documents, and has been widely used as a logical data model. Using XML as a logical database model, it requires a conceptual model for the semantics that XML has. However, the existing conceptual models, such as Entity Relationship models and UML, have been extended their concepts to express the specific characteristics of XML, but so far, there are no standard models. This paper compares the characteristics of the typical model of conceptual model of XML by Extended Entity Relationship model from the perspective of database field. For this, we propose the requirements that must be met for XML, and on the basis of these requirements, the approaches of each model are compared.

• Proceedings of the KAIS Fall Conference
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• 2006.11a
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• pp.290-293
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• 2006

The goal of research is to propose a framework for drawing data search system which is based on the web. The existing search systems were reviewed in the form of case studies and thereby the limitation were addressed: the unsystematic translation between the presentational building model and the discursive design criteria. besides the limited area in sharing and space. Therefore, a web-based drawing search with common structure which building representational model and building behavior model is proposed. The system contains a number of phases: firstly, a user is required to build a building model with the proposed building representational model and then this model is automatically transformed into an aspect model; secondly, a user is also required to present his query in form of the propose building behavior model by web page; finally, these two models - building representational model and building behavior model - are compared by database data so as to retrieve the proper result.