• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제4권9호
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• pp.371-376
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• 2015

사물인터넷 (IoT)은 데이터의 양을 상당히 증가시킨다. 데이터베이스 압축은 저장 시스템 비용과 I/O 대역폭을 절약할 수 있기 때문에 빅데이터에 있어서 중요하다. 그러나 데이터베이스 압축은 압축된 페이지에 대한 업데이트로 인해 OLTP와 같은 쓰기 집중적인 워크로드에 대해 낮은 성능을 보일 수 있다. 본 논문에서는 데이터베이스 압축의 성능 향상을 위한 실용적 가이드라인을 제시한다. 특히, 압축 페이지 크기에 의한 계산으로부터 예상되는 공간 절약과 거의 같은 공간 절약을 보이는 테이블들만을 압축하는 SELECTIVE 전략을 제시한다. TPC-C 벤치마크와 MySQL을 이용한 실험을 통해 SELECTIVE 전략이 압축하지 않는 방법에 비해 1.1배 높은 성능을 보이면서 17.3%의 공간을 절약한다는 것을 보였다.

• 인터넷정보학회논문지
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• 제6권1호
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• pp.73-84
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• 2005

ALTIBASE/sup TM/ 시스템은 메인 메모리를 주 저장장치로 사용하는 관계형 주기억장치 DBMS이다. 본 논문에서는 최근 데이터베이스 응용들의 요구사항으로 부각되고 있는 데이터베이스의 고가용성과 실시간 데이터베이스 시스템의 높은 트랜잭션 처리율을 동시에 보장하기 위하여 ALTIBASETM시스템의 구조 및 설계에 대하여 기술한다. 특히, 고가용성 보장을 위한 ALTIBASETM 시스템의 이중화 기능에 대하여 논의한다. 이중화 기법의 분류를 통해 다른 기법과의 비교를 하였으며, 이중화 관리를 위한 프로세스 구조 및 이중화 통신 모델, 프로토콜에 대하여 설명한다. 또한, 다양한 실험을 통하여 트랜잭션 처리율을 측정하였으며, 이중화 기능을 지원하기 위해 요구되는 오버헤드를 독립 시스템의 성능과 비교하여 측정하였다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.623-626
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• 2006

Group of genes controls the functioning of a cell by complex interactions. These interacting gene groups are called Gene Regulatory Networks (GRNs). Two previous data mining approaches, clustering and classification have been used to analyze gene expression data. While these mining tools are useful for determining membership of genes by homology, they don't identify the regulatory relationships among genes found in the same class of molecular actions. Furthermore, we need to understand the mechanism of how genes relate and how they regulate one another. In order to detect regulatory relationships among genes from time-series Microarray data, we propose a novel approach using frequent pattern mining and chain rule. In this approach, we propose a method for transforming gene expression data to make suitable for frequent pattern mining, and detect gene expression patterns applying FP-growth algorithm. And then, we construct gene regulatory network from frequent gene patterns using chain rule. Finally, we validated our proposed method by showing that our experimental results are consistent with published results.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.619-624
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• 2000

Design of experiments based on Taguchi's orthogonal array is utilized for exploring the design space and for building response surface models of insulator and isolator database in order to facilitate the effective solution of multi-objective optimization commonly occurred in NVH problems. Response surface models, called engineering database of design space, provide an efficient means to rapidly model the trade-off among many conflicting NVH goals in automotive. In the design of insulator and isolator in automotive interior part, it is important not only to construct effective matrices of NVH but also to build up engineering database of current products. The experimental design especially based on orthogonal array and the nonlinear optimization algorithms are successfully used together to obtain the optimal design of insulator and isolator. The $2^{nd}$ order response surface models of absorption coefficient and insertion loss are constructed by using modified Taguchi's $L_{12}2^13^7$ orthogonal array and successfully used in optimal design of insulator and isolator.

• 정보처리학회논문지D
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• 제12D권1호
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• pp.13-20
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• 2005

조인 연산은 데이터베이스 시스템의 가장 기본적이고 중요한 연산이며, 큰 수행 비용을 필요로 하는 연산이다. 지금까지 효율적인 조인 연산의 구현과 평가를 위한 다양한 연구가 진행되었다. 기존의 조인 연산 평가는 구현자 관점에서 우수한 알고리즘을 규명하기 위해 개발되었다. 본 논문은 사용자 관점에서 조인 연산 성능을 평가하는 조인 연산 평가 방법론을 기술한다. 본 성능 평가는 사용자가 자신의 업무에 적합한 조인 연산을 수행하는 데이터베이스 시스템을 선택하는데 도움을 준다. 본 논문에서는 두 가지 조인 범주와 여섯 가지의 조인 성능 영향 요소를 고려하여 42개의 평가 질의를 제안한다. 마지막으로 제안된 방법론에 따라 두 개의 상용 데이터베이스 시스템을 대상으로 구현하고 성능 평가 결과를 기술하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제4권2호
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• pp.154-173
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• 2010

Database outsourcing is unavoidable in the near future. In the scenario of data stream outsourcing, the data owner continuously publishes the latest data and associated authentication information through a service provider. Clients may register queries to the service provider and verify the result's correctness, utilizing the additional authentication information. Research on On-line Stream Analytics (OLSA) is motivated by extending the data cube technology for higher multi-level abstraction on the low-level-abstracted data streams. Existing work on OLSA fails to consider the issue of database outsourcing, while previous work on stream authentication does not support OLSA. To close this gap and solve the problem of OLSA query authentication while outsourcing data streams, we propose MDAHRB and MDAHB, two multi-dimensional authentication approaches. They are based on the general data model for OLSA, the stream cube. First, we improve the data structure of the H-tree, which is used to store the stream cube. Then, we design and implement two authentication schemes based on the improved H-trees, the HRB- and HB-trees, in accordance with the main stream query authentication framework for database outsourcing. Along with a cost models analysis, consistent with state-of-the-art cost metrics, an experimental evaluation is performed on a real data set. It exhibits that both MDAHRB and MDAHB are feasible for authenticating OLSA queries, while MDAHRB is more scalable.

• 한국CDE학회논문집
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• 제14권6호
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• pp.404-414
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• 2009

In the computational molecular analysis, 3D structural comparison for protein searching plays a very important role. As protein databases have been grown rapidly in size, exhaustive search methods cannot provide satisfactory performance. Because exhaustive search methods try to handle the structure of protein by using sphere set which is converted from atoms set, the similarity calculation about two sphere sets is very expensive. Instead, the filter-and-refine paradigm offers an efficient alternative to database search without compromising the accuracy of the answers. In recent, a very fast algorithm based on the inter-atomic distance has been suggested by Ballester and Richard. Since they adopted the moments of distribution with inter-atomic distance between atoms which are rotational invariant, they can eliminate the structure alignment and orientation fix process and perform the searching faster than previous methods. In this paper, we propose a new 3D shape descriptor. It has properties of the general shape distribution and useful property in screening the molecular database. We show some experimental results for the validity of our method.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제3권3호
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• pp.135-138
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• 2014

본 논문에서는 2D-DCT와 EHMM 알고리즘을 이용하여 과적합에 강인한 얼굴 표정인식 방법을 고안하였다. 특히, 본 논문에서는 2D-DCT 특징추출을 위한 윈도우 크기를 크게 설정하여 EHMM의 관측벡터를 추출함으로써, 표정인식 성능 향상을 도모하였다. 제안 방법의 성능평가는 공인 CK 데이터베이스와 JAFFE 데이터베이스를 이용하여 수행되었고, 실험 결과로부터 특징추출 윈도우의 크기가 커질수록 표정 인식률이 향상됨을 확인하였다. 또한, CK 데이터베이스를 이용하여 표정 모델을 생성하고 JAFFE 데이터베이스 전체 샘플을 테스트한 결과, 제안 방법은 87.79%의 높은 인식률을 보였으며, 기존의 히스토그램 특징 기반의 표정인식 접근법보다 46.01~50.05%의 향상된 인식률을 보였다.

• ETRI Journal
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• 제42권2호
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• pp.217-229
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• 2020

Long-term electroencephalography (EEG) monitoring is time-consuming, and requires experts to interpret EEG signals to detect seizures in patients. In this paper, we propose a novel automated method called adaptive slope of wavelet coefficient counts over various thresholds (ASCOT) to classify patient episodes as seizure waveforms. ASCOT involves extracting the feature matrix by calculating the mean slope of wavelet coefficient counts over various thresholds in each frequency subband. We validated our method using our own database and a public database to avoid overtuning. The experimental results show that the proposed method achieved a reliable and promising accuracy in both our own database (98.93%) and the public database (99.78%). Finally, we evaluated the performance of the method considering various window sizes. In conclusion, the proposed method achieved a reliable seizure detection performance with a short-term window size. Therefore, our method can be utilized to interpret long-term EEG results and detect momentary seizure waveforms in diagnostic systems.

• Genomics & Informatics
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• 제8권2호
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• pp.90-93
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• 2010

A-kinase-anchoring proteins (AKAPs) are scaffold proteins which compartmentalize protein kinase A (PKA, cAMP-dependent protein kinase) and other enzymes to specific subcellular sites. The spatiotemporal control of these enzymes by AKAPs is important for cellular function like cell growth and development etc. Hence, it is important to understand the basic function of AKAPs and their functional domains. However, diverse names, function, cellular localizations and many members of AKAPs increase difficulties when researchers search appropriate AKAPs for their experimental purpose. Nevertheless, there was no previous AKAPs-related database regardless of their important cellular functions and difficulty of finding appropriate AKAPs. So, we developed AKAPs database (AKAPDB), which contains their sequence information, functions and other information derived from prediction programs and other databases. Therefore, we propose that AKAPDB can be an important tool to researchers in the related fields. AKAPDB is available via the internet at http://plaza3.snu.ac.kr/akapdb/.