• Journal of KIISE:Databases
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• v.36 no.3
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• pp.226-234
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• 2009

A data stream is a massive unbounded sequence of data elements continuously generated at a rapid rate. Due to the characteristics of a data stream, it is impossible to save all the data elements of a data stream. Therefore it is necessary to define a new synopsis structure to store the summary information of a data stream. For this purpose, this paper proposes a cuboid prefix tree that can be effectively employed in evaluating an iceberg query over data streams. A cuboid prefix tree only stores those itemsets that consist of grouping attributes used in GROUP BY query. In addition, a cuboid prefix tree can compute multiple iceberg queries simultaneously by sharing their common sub-expressions. A cuboid prefix tree evaluates an iceberg query over an infinitely generated data stream while efficiently reducing memory usage and processing time, which is verified by a series of experiments.

• The Transactions of the Korea Information Processing Society
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• v.7 no.11S
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• pp.3603-3612
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• 2000

This paper presents is for the design and implementation of EDI document exchange system based on XML To create a customized document of the users' choice, it designed and created the transaction processor and the template manager, and to make it accessable with the original EDI, a converter function is included, Also, on this system, this protocol stores EDI message structure that needed to exchange as XML format and controls it as DOM API for user can use previous system, And provides interface for user can create template files with converter and transfer necessary elements that can be chosen by user. For this purpose, This system proposes a shows structure information and document converting mechanism solution of EDI documents based on by using XML which does not show proper document conversion mechanism solution in other system so far.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.10
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• pp.1957-1967
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• 2007

User can be offered various information form internet and reserve. However this operation is hard to be satisfied with user's requirement. Because it offer the alternative by self-mediation and the place where offer the information is distributed and a form or stored f[nm of data would be different. These cases occurred in change of enterprise recently. In a process of M&A, outsourcing or cooperation. necessity of new strategy become a pressing issue for ensuring interoperability on application, database of each enterprise and integration information management. Thus, interoperability of distributed data is a base condition for cooperation of legacy system, it will solve a problem such as available or clarity of data, problem of cooperation system. This paper use a XMDR for integration of distributed system and ensuring interoperability. By using XMDR, integrate a traveling information system and it will be solve the problem of interoperability and variety data problem that be occurred in integration of data by suggesting a technique of transaction management.

• Journal of IKEEE
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• v.23 no.2
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• pp.508-516
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• 2019

Smart home with various IoT devices provides convenient and efficient services. However, security is important because sensitive information such as private video and audio can be collected and processed, as well as shared over the Internet. To manage such smart home IoT devices, we use blockchain technology that provides data integrity and secure management. In this paper, we utilize a PoS(Proof of Stake) method that verifies the block through the accumulated stake in the network rather than the computation power, out of the PoW(Proof of Work) block chain, in which the computation for the existing verification must be continuously performed. Among them, we propose a blockchain based system with DPoS(Delegated Proof of Stake) method to actively solve the scalability part, for security that is suitable for smart home IoT environment. We implement the proposed system with DPoS based EOSIO to show realization, and we show performance improvement in terms of transaction processing speed.

• The KIPS Transactions:PartC
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• v.10C no.4
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• pp.433-440
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• 2003

According as the real economic activities are carried out in the cyber world and the identity problem of a trade counterpart emerges, digital signature has been diffused. Due to the weakness for real-time validation using the validation method of digital signature, Certificate Revocation List, On-line Certificate Status Protocol was introduced. In this case, every transaction workload requested to verify digital signature is concentrated of a validation server node. Currently this method has been utilized on domestic financial transactions, but sooner or later the limitation will be revealed. In this paper, the validation method will be introduced which not only it can guarantee real-time validation but also the requesting node of certificate validation can maintain real-time certificate status information. This method makes the revocation management node update the certificate status information in real-time to the validation node while revoking certificate. The characteristic of this method is that the revocation management node should memorize the validation nodes which a certificate holder uses. If a certificate holder connects a validation node for the first time, the validation node should request its certificate status information to the above revocation management node and the revocation management node memorizes the validation node at the time. After that, the revocation management node inform the revocation information in real-time to all the validation node registered when a request of revocation happens. The benefits of this method are the fact that we can reduce the validation time because the certificate validation can be completed at the validation node and that we can avoid the concentration of requesting certificate status information to a revocation node.

• Journal of KIISE:Computing Practices and Letters
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• v.7 no.1
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• pp.24-37
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• 2001

This paper deals with our experience for the design and implementation of Transport and Session managers in the Integrated Streaming Service Architecture (IS SA) that was developed by the authors. The ISSA is a streaming framework that allows to develop integrated multimedia streaming applications such as VOD system in unicast/multicast and real-time broadcastOive-cast). It also facilities standard real-time transport protocols such as RTp(Real-Time Transport Protocol)/RTCP(Real-time Control Protocol) and RTSP(Real-Time Streaming ProtocoD that allows to user openness. The ISSA supports diverse media fonnats and is independent from underlying networks and operating systems, and compatible with the global real-time multimedia database system (BeeHive) so that streaming media are efficiently retrieved, stored, and serviced. The role of the Transport Manager is to do packetization and depacketization for the different types of multimedia data and delivers the packetized media data in real-time. The Transport Manager uses RTP protocol. The role of the Session Manager is to establish and control the media channel by using RTSP protocol and to deliver the database transactions for the multimedia database by using RTTP(Real-Time Transaction Protocol) protocol. Both the Transport and Session Manager are doing their functions through the network interface in the ISSA that allows developers to various network programming interfaces and provides flexibility to the system.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.3
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• pp.513-525
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• 2022

The immutability of blockchain is core elements of security of blockchain and guarantee data integrity. However, the characteristic that the data recoreded once in the blockchain cannot be modified has place for abuse by a specific user. In fact improper contents that is inappropriate to be recorded on the blockchain, such as harmful data and user personal data, is exposed on Bitcoin. As a way to manage improper content existing in the blockchain, there is a redactable blockchain using chameleon hash proposed for the first time by Ateniese. The redactable blockchain meet the right to be forgotten of GDPR by allowing data modification and deletion. Recently, Research on personal data management is being conducted in a redactable blockchain. Research by Jia et al. proposed a model that enables users to manage their personal data in the redactable blockchain. However, semi trusted regulators, which are blockchain participation nodes, have powerful authority in the blockchain, such as modification rights and deprivation of transaction rights for all blocks, which may cause side effects. In this paper, to weaken the authority of regulators in Y. Jia et al., we propose a method of authority subject altering and authority sharing, and propose a redactable blockchain-based authority change and access control system model based on applicable scenarios.

• The Transactions of the Korea Information Processing Society
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• v.4 no.4
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• pp.895-907
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• 1997

The mining of assciation rules disovers the trndency of events ocuring simultaneously in large databases. Previous announced research on association rules deals with associations with associations with respect to the whole transaction. However, xome association rules could have very high confidence in a sub-range of the time domain, even though they do not have quite high confidence in the whole time domain. Such kind of association rules are ecpected to be very usdful in various decion making problems.In this paper, we define transient association rule, as an association with high cimfidence worthy of special attention in a partial time interval, and propose an dfficeint algorithm wich finds out the time intervals appropriate to transient association rules from large-databases.We propose the data-driven retrival method excluding unecessary interval search, and design an effective data structure manageable in main memory obtined by one scanning of database, which offers the necessary information to next retrieval phase. In addition, our simulation shows that the suggested algorithm has reliable performance at the time cost acceptable in application areas.

• Journal of KIISE:Software and Applications
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• v.26 no.8
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• pp.955-963
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• 1999

다단계 보안 실시간 데이타베이스 시스템은 데이타베이스의 일관성 유지와 실시간 요구인 마감시간의 만족, 그리고 기밀성을 띤 데이타가 노출될 수 있는 비밀채널(covert-channel)의 방지라는 요구사항을 모두 만족해야 한다. 기존의 SRT-2PL(Secure Real-Time 2 Phase Locking)은 원본과 복사본으로 데이타 객체를 분리시켜 다른 등급간에 불간섭(non-interference)을 유지하여 비밀채널의 방지를 가능하게 하였으나, 복사본이 모든 데이타 객체에 대해 항상 존재하므로 메모리의 낭비가 있을 수 있고, 복사본의 갱신을 위한 갱신 큐의 관리에 따르는 오버헤드와 그에 따른 예측성 결여라는 문제점을 갖고 있다. 이를 개선하기 위하여 본 논문에서는 다단계 보안 실시간 데이타베이스 시스템의 요구사항을 모두 만족하는 동적 복사 프로토콜을 제안한다. 동적 복사 프로토콜은 로킹 기법을 기초로 동작하고, 트랜잭션의 작업에 따라 동적으로 복사본을 생성하고 삭제한다. 모의 실험 결과 제안한 동적 복사 프로토콜은 비밀채널을 방지하고 동적인 복사본의 생성으로 SRT-2PL의 단점인 메모리 낭비를 줄일 수 있으며, 예측성을 높여 마감시간 오류율을 감소시켰다.Abstract Concurrency control of real-time secure database system must satisfy not only logical data consistency but also timing constraints and security requirements associated with transactions. These conflicting natures between timing constraints and security requirements are often resolved by maintaining several versions(or secondary copies) on the same data items. In this paper, we propose a new lock-based concurrency control protocol, Dynamic Copy Security Protocol, ensuring both two conflicting requirements. Our protocol aims for reducing the storage overhead of maintaining secondary copies and minimizing the processing overhead of update history. Main idea of our protocol is to keep a secondary copy only when it is needed to resolve the conflicting read/write operations in real time secure database systems. For doing this, a secondary copy is dynamically created and removed during a transaction's read/write operations according to our protocol. We have also examined the performance characteristics of our protocol through simulation under different workloads while comparing the existing real time security protocol. The results show that our protocol consumed less storage and decreased the missing deadline transactions.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.6
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• pp.1435-1447
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• 2015

Finance Companies are operating a security solution such as E-DRM(Enterprise-Digital Right Management), Personal information search, DLP(Data Loss Prevention), Security of printed paper, Internet network separation system, Privacy monitoring system for privacy leakage prevention by insiders. However, privacy leakages are occurring continuously and it is difficult to the association analysis about relating to the company's internal and external distribution of private document. Because log system operated in the separate and independent security solutions. This paper propose a systematic chains that can correlatively analyze business systems and log among heterogeneous security solutions organically and consistently based on security documents. Also, we suggest methods of efficient detection for Life-Cycle management plan about security documents that are created in the personal computer or by individual through the business system and distribution channel tracking about security documents contained privacy.