• Journal of KIISE
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• v.43 no.12
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• pp.1385-1395
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• 2016

In the era of Big Data, NoSQL databases provide solutions for problems, circumventing the limitations of traditional relational databases by using new architectures and data model. Contrary to relational database products, the range of the features architectures, and limitations of NoSQL databases is very broad. Thus, choosing the right database products requires more considerations and difficulties. The advent of NoSQL does not only promote the abundance of NoSQL products, but also stimulates the relational database realm to expand their features beyond the relational model. In order to understand NoSQL trends more accurately, here we discuss and compare NoSQL databases with relational databases. We also present the newest features associated with NoSQL in one of the most advanced open-source relational databases, PostgreSQL. To discuss future directions for PostgreSQL we analyzed the performance of NoSQL and PostgreSQL by conducting experiments using the NoSQL benchmark tool (YCSB).

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.867-869
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• 2015

최근 폭발적으로 증가하는 데이터양과 데이터 특성들로 인해 관계형 데이터베이스는 빅데이터 처리에 어려움이 발생하기 시작했으며, 이러한 빅데이터의 신속한 처리를 위해 비정형 데이터 분산처리, 병렬 처리 등 특정한 영역에서 우수한 성능을 보이는 NoSQL 데이터베이스의 활용이 증가하고 있다. 기존 관계형 데이터베이스에서 악의적인 SQL Injection 공격이 시스템에 치명적인 피해를 주는 것과 마찬가지로, 다른 쿼리 언어를 사용하는 NoSQL 데이터베이스에서도 Injection 공격에 대한 취약점이 여전히 존재할 뿐만 아니라, NoSQL 데이터베이스가 비교적 최신 기술이기 때문에 개발자들은 Injection 공격에 대한 인식이 부족한 실정이다. 본 논문에서는 NoSQL 데이터베이스에 대한 대표적인 2가지 Injection 공격 방법을 소개하고, "NoSQL Injection Defender(NID)"라 명명한 Injection 공격 방어 시스템의 설계 방안을 제시하고자 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.04a
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• pp.591-594
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• 2016

최근 빅데이터 시대의 도래로 대량의 데이터에 대한 처리 및 분석 요구가 증가되면서 빅데이터를 저장하기 위해 개발된 NoSQL 데이터베이스 내의 조인 연산 필요성이 증대되고 있다. 빅데이터 환경에서는 다중 저장소 지속성의 개념에 따라 여러 NoSQL 데이터베이스를 동시 복합적으로 사용해야 하므로 이기종 NoSQL 데이터베이스간의 조인 연산이 중요시 되고 있다. 하지만 NoSQL 데이터베이스에서는 데이터 처리 과정에서 발생하는 오버헤드로 인해 조인 연산을 지원하지 않거나 조인 연산 시 성능저하가 발생한다. 이러한 조인 연산에 대한 오버헤드를 줄이기 위해 애플리케이션 단에서 맵리듀스 프레임워크를 활용한 다양한 조인 전략 연구들이 제시되었지만 단일 NoSQL 데이터베이스를 위한 방법이며 조인에 참여하는 데이터의 특성 및 연관성을 사전에 파악하고 있어야하는 한계점이 존재한다. 본 논문은 조인 연산에 참여하는 데이터에 대한 사전 정보 없이 빅데이터 환경에서 이기종 NoSQL 데이터베이스간의 조인 연산을 지원하기 위해 데이터 집합 분석, 질의 재배치, 조인 전략 자동 선정, 조인 결과가 저장될 데이터베이스 자동 선택 단계를 통한 지능적 조인 처리 기법을 제시한다.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.5
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• pp.117-126
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• 2016

Recently, increasing utilization of Big Data or Social Network Service involves the increases in demand for NoSQL Database that overcomes the limitations of existing relational database. A forensic examination of Relational Database has steadily researched in terms of Digital Forensics. In contrast, the forensic examination of NoSQL Database is rarely studied. In this paper, We introduce Redis (which is) based on Key-Value Store NoSQL Database, and research the collection and analysis of forensic artifacts then propose recovery method of deleted data. Also we developed a recovery tool, it will be verified our recovery algorithm.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.2
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• pp.95-104
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• 2017

As the technology in smart device is growing and Social Network Services(SNS) are becoming more common, the data which is difficult to be processed by existing RDBMS are increasing. As a result of this, NoSQL databases are getting popular as an alternative for processing massive and unstructured data generated in real time. The demand for the technique of digital investigation of NoSQL databases is increasing as the businesses introducing NoSQL database in their system are increasing, although the technique of digital investigation of databases has been researched centered on RDMBS. New techniques of digital forensic investigation are needed as NoSQL Database has no schema to normalize and the storage method differs depending on the type of database and operation environment. Research on document-based database of NoSQL has been done but it is not applicable as itself to other types of NoSQL Database. Therefore, the way of operation and data model, grasp of operation environment, collection and analysis of artifacts and recovery technique of deleted data in HBase which is a NoSQL column-based database are presented in this paper. Also the proposed technique of digital forensic investigation to HBase is verified by an experimental scenario.

• Journal of the Korea Society of Computer and Information
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• v.25 no.9
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• pp.1-9
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• 2020

In this paper, we propose a method of in-depth analysis of internal operation process by recording library calls and related information that occur in the operation process of NoSQL database. It observes and records the specified library calls, compares the internal behavior differences between the NoSQL databases through recorded library call information, and evaluates the characteristics and scalability of each database by observing changes in the number of input data. The development of computing performance and the activation of big data have led to the emergence of different types of NoSQL databases for recording and analyzing various and large amounts of data, and it is necessary to evaluate the scalability of each database in order to select a database suitable for each environment. However, it is difficult to analyze or predict how a database operates in traditional ways, such as benchmarking, observing external behavior through performance models, or analyzing structural features based on design. Therefore, it is necessary to utilize the techniques proposed in this paper to understand the scalability of NoSQL databases with high accuracy.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.223-225
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• 2013

For a long time, Relational Databases have been widely used in many enterprises. Even though the Relational Databases have merits such as excellent power of data preservation, concurrency controlling as a standard model in databases, there are a demerit in the inconsistency of objects and relations. Against this backdrop, NoSQL is being magnified as a new solution for Big Data since it can be operated without any schema. In this paper, we research on not only merits and demerits of Relational Databases but also the comparison between application databases and integrated databases. And then, we define NoSQL for Big Data and check its characteristics.

• The Journal of the Korea Contents Association
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• v.17 no.7
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• pp.93-100
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• 2017

Recently, demands for high-performance flash-based storage devices (i.e., flash SSD) have rapidly grown in social network services, cloud computing, super-computing, and enterprise storage systems. The industry and academic communities made the NVMe specification for high-performance storage devices, and NVMe-based flash SSDs can be now obtained in the market. In this article, we evaluate performance of NoSQL databases that social network services and cloud computing services heavily adopt by using NVMe-based flash SSDs. To this end, we use NVMe SSD that Samsung Electronics recently developed, and the SSD used in this study has performance up to 3.5GB/s for sequential read/write operations. We use WiredTiger for NoSQL databases, and it is a default storage engine for MongoDB. Our experimental results show that log processing in NoSQL databases is a major overhead when high-performance NVMe-based flash SSDs are used. Furthermore, we optimize components of log processing and optimized WiredTiger show up to 15 times better performance than original WiredTiger.

• Proceedings of the Korea Contents Association Conference
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• 2019.05a
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• pp.445-446
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• 2019

빅데이터 시대의 도래로 다양한 NoSQL 데이터베이스 엔진이 활용되고 있다. NoSQL 데이터베이스 엔진 기반의 다양한 응용들이 수행될 때 스토리지의 성능을 평가하기 위한 스토리지 벤치마킹 툴이 요구된다. 본 논문에서는 NoSQL 데이터베이스를 이용한 스토리지 벤치마킹 시스템을 설계한다. 제안하는 스토리지 벤치마킹 시스템은 IO 추적기를 통해 스토리지의 성능을 측정하고, 웹 UI를 통해 사용자 정의 워크로드 생성, 벤치마킹 실행, 결과 확인을 수행할 수 있다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.3
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• pp.298-305
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• 2016

Various NoSQL databases are more excellent to process a large amount of big data than existing relational databases such as MySQL, PostgreSQL and Oracle. Among widely used NoSQL databases, performance of HBase, Cassandra, MongoDB and Redis was comparatively assessed. For distributed processing of a large amount of data, 12 servers were connected through switching hub and Ubuntu was installed as operating system. As for benchmark tool, YCSB was applied. Read and update ratios changed from 50% and 50%, 95% and 5% and finally, 100% and 0% and each of them was assessed as 200,000 commands developed into 1,200,000 commands for each case. Cassandra was most excellent with transaction processing per second while MongoDB was most excellent with the number of processes carried out per unit time.