• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.12B
• /
• pp.1407-1417
• /
• 2009

We propose a e-document management system that can provide segmented page information on a document according to different levels of authority from access control environment. The proposed system creates hierarchy identifier using a one-way hash chain and therefore does not need to own key information for all users as in existing system. Also by creating group keys by compounding hash chain hierarchy identifier with randomly formed group identifier, the system can flexibly respond to dynamic changes from group member movements while at the same time resolving the problems of key formation and management in document encoding technique using symmetric key for each page. Lastly as a result of comparative analysis through an experiment with existing e-document management systems, the proposed system showed superiority in the efficiency of encoding and decoding document and the speed of encoding and decoding by the pages.

• The Journal of Society for e-Business Studies
• /
• v.19 no.4
• /
• pp.151-168
• /
• 2014

UCI (Universal Content Identifier) as a national digital content identification system for identifying digital content and ICN (Integrated Copyright Number) for copyright management are operated by Korea copyright commission. However, They are not interoperable with international standard identification system such as ISRC (International Standard Recording Code), ISWC (International Standard Works Code), and ISAN (International Standard Audiovisual Number) due to lack of linkage system. Hence, extra works with international standard identification system are needed for international market entry and integrated management of statistical information including content settlement in international market is impossible. In this paper, the domestic/international identification systems are surveyed, and by metadata analysis of identification systems, linkage method with UCI/ICN is proposed. And also by developing the prototype model, research direction to UCI/ICN with international standard identification system is proposed.

• Smart Media Journal
• /
• v.13 no.4
• /
• pp.76-85
• /
• 2024

In this paper, we propose a system that improves the data integrity of IoT(Internet of Things) devices in the virtual environment by combining Hyperledger Indy and MQTT(Message Queuing Telemetry Transport). The system complements the limitations of the centralized system by realizing a DPKI(Decentralized Public Key Infrastructure) structure that utilizes a distributed network in publish-subscribe(pub/sub) pattern communication. Digital signature technology was applied to ensure the data integrity of IoT devices and communication scenarios between the four core components of the client, IoT device, broker, and blockchain, as well as a topic structure using a decentralized identifier to ensure safety in the virtual environment. We present a systematic method for transparent data exchange. To prove the performance of the proposed system, this paper conducted experiments on four scenarios and evaluated communication performance in a virtual environment. The experimental results confirmed that the proposed system provides a reliable IoT data communication structure in a virtual environment.

• Journal of Advanced Marine Engineering and Technology
• /
• v.23 no.6
• /
• pp.738-747
• /
• 1999

Vector controlled induction motor have been widely used in high performance applications. How-ever the performance is sensitive to the variations of motor parameters especially the rotor time constant which varies with the temperature and the saturation of the magnetizing inductance. In this paper the authors propose new identifying method for time-varying parameters of an induction motor which is based on adaptive vector control with serial block algorithm. Vector con-trol system realized on synchronous frame and parameter identification system realized on sta-tionary frame are not easily affected by the vector control frame. Parameter mismatch in the control system results in heavy transient variation in speed and torque response. In order to compensate degradation of the responses at the middle and low speed region adaptive identifier is introduced. To verify the feasibility of this technique compute simu-lations carried out.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2010.11a
• /
• pp.1050-1052
• /
• 2010

Locator and Identifier Split is considered as the solution to the scalability problem Internet is facing today. The separation approach of Locator and Identifier requires a third party called mapping system. The mapping system enables the inter-domain routing between two different edge networks. The design of this third party has generated many proposals, among them one approach use Border Gateway Protocol (BGP) for effective mapping information updates distribution. In this paper, we take advantage of this approach by considering the scalability in term of mapping information storage. Our goal is to provide scalability in term of mapping information storage as well as effective mapping information updates distribution.

• Journal of Korea Multimedia Society
• /
• v.10 no.7
• /
• pp.807-816
• /
• 2007

Since W3C proposed XML in 1996, XML documents have been widely spreaded in many internet documents. Because of this, needs for research related with XML is increasing. Especially, it is being well performed to study XML management system for storage, retrieval, and management with XML Documents. Among these studies, XRel is a representative study for XML management and has been become a comparative study. In this study, we suggest XML documents management system based on Relational DataBase Management System. This system is stored not all possible path expressions such as XRel, but filtered path expression which has text value or attribute value. And by giving each node Node Expression Identifier, we try to match given Node Expression Identifier. Finally, to prove efficiency of the suggested technique, this paper shows the result of experiment that compares XPath query processing performance between suggested study and existing technique, XRel.

• Transactions on Control, Automation and Systems Engineering
• /
• v.2 no.3
• /
• pp.207-213
• /
• 2000

This paper introduces a high-performance speed control system based on artificial neural networks(ANN) to estimate unknown parameters of a DC servo motor. The goal of this research is to keep the rotor speed of the DC servo motor to follow an arbitrary selected trajectory. In detail, the aim is to obtain accurate trajectory control of the speed, specially when the motor and load parameters are unknown. By using an artificial neural network, we can acquire unknown nonlinear dynamics of the motor and the load. A trained neural network identifier combined with a reference model can be used to achieve the trajectory control. The performance of the identification and the control algorithm are evaluated through the simulation and experiment of nonlinear dynamics of the motor and the load using a typical DC servo motor model.

• Proceedings of the KIPE Conference
• /
• 1998.10a
• /
• pp.11-16
• /
• 1998

In this paper, simultaneous estimation of rotor speed and time constant for a voltage source inverter (VSI) fed induction motor drive are disccussed. The theory is based on the Model Reference Adaptive System (MRAS). The identifier executes Simultaneous rotor speed and time constant so that vector control of the induction may be achieved in the rotor-flux oriented reference frame. Furthermore, to eliminate the offset error caused by the change in the stator resistance, a fuzzy resistance regulator is also designed which operates in parallel with the rotor speed and time constant identifier

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.37 no.12
• /
• pp.894-902
• /
• 1988

In this paper, a method for the design of robust adaptive controller using the heuristic rules of industrial engineers is presented. This scheme works on the basis of heuristic rules and includes a supervisor, a system identifier and a detuner. The supervisor detects onsetting instability based on the analysis of the amplitude and the trend of error signal, also selects running controllers. Upon detecting instability, the controller is switched to a PID algorithm and run recursively until stability is restored. Simultaneously, new input / output data is gathered and the system identifier runs to get critical sensitivity (kc) and critical period(tc). Based on the new values(kc, tc), a GPC controller is redesigned and normal GPC is finally run. The algorithm described in this paper belongs to the supervised adaptive control category with a limited use of heuristic rules. Finally, we show the robust of this scheme by simulated example.

• Journal of Korea Multimedia Society
• /
• v.24 no.6
• /
• pp.760-767
• /
• 2021

The identity verification is one of the most important technologies in online services. Many services in society are provided online, and the service is provided after confirming the user's identity. Users can do a lot of things online, but they also have side effects. Online digital information is easily manipulated and it is difficult to verify its authenticity, causing social confusion. Accordingly, there has been a movement for individuals to directly manage their identity information using DID. In this paper, we propose a system that can authenticate identity by directly adding own personal information and issuing an identifier using DID technology based on a private blockchain. Then, to verify the proposed system, the scenario is executed and verified.