• 한국IT서비스학회:학술대회논문집
• /
• 2005.05a
• /
• pp.562-571
• /
• 2005

본 연구에서는 정보시스템 구축 ${\cdot}$ 운영에 필요한 하드웨어 도입시 용량산정의 객관성을 확보하고 아울러 정보시스템 업무유형 및 규모를 감안한 용량산정 기준을 설정하기 위하여 CPU를 중심으로 메모리와 하드디스크의 용량을 적절히 산출할 수 있는 용량산정식과 용량산정식에 포함될 항목 및 각 항목별 중요도(입력값의 범위)를 실증적으로 도출하였다. 실증분석은 기존연구에서 설정된 용량산정 프레임워크와 하드웨어 용량산정 지침을 바탕으로 설문조사 및 전문가 집단토의 방식을 병행하여 수행하였다. 실증분석 및 전문가집단의 토의결과 CPU(WEB/WAS 및 OLTP), 메모리, 디스크에 대한 용량산정식의 타당도 및 각 용량산정식에 포함될 항목별 입력값의 범위 와 기타 부가적으로 정보시스템의 유형(개발목적과 구축영역)에 따른 항목별 중요도가 각각 도출되었다. 본 연구의 주요의의로는 공공기관의 실무 전문가들을 대상으로 실행적 측면에서 용량산정식의 타당도를 확인하였으며, 항목별 입력값의 경우에도 정형화된 설문서를 통하여 기존 연구들에서 설정된 정보시스템 용량산정식의 객관성을 확보하였다는 점이다. 또한, 주로 공급업체 전문가의 자의적 판단에 따라 설정된 입력값의 범위 등을 공공기관의 현업전문가를 통하여 실증적으로 검증하고 확인하였다는 점이다.

• Journal of Digital Contents Society
• /
• v.19 no.2
• /
• pp.335-341
• /
• 2018

There exists a limit in efficient processing of mixed workloads that database markets requires in recent years since existing database systems utilize a static page storage model. In this paper we propose a dynamic page storage model that can reflect the characteristics of mixed workloads. We also describe how to extract optimized column groups from given mixed workloads and how to construct pages dynamically. Finally, we show in our experiments that the proposed model is more efficient than the existing model in processing given mixed workloads.

• The KIPS Transactions:PartD
• /
• v.16D no.3
• /
• pp.295-306
• /
• 2009

Query execution time minimization is an important objective in distributed database design. While total time minimization is an objective for On Line Transaction Processing (OLTP), response time minimization is for Decision Support queries. We formulate the sub-query allocation problem using analytical models and solve with genetic algorithm (GA). We show that query execution plans with total time minimization objective are inefficient from response time perspective and vice versa. The procedure is tested with simulation experiments for queries of up to 20 joins. Comparison with exhaustive enumeration indicates that GA produced optimal solutions in all cases in much less time.

• The Journal of Bigdata
• /
• v.4 no.2
• /
• pp.207-220
• /
• 2019

Recent developments in information and communication technology has enabled the deployment of sensor based data to provide real-time services. In Korea, The Korea Transportation Safety Authority is collecting driving information of all commercial vehicles through a fitted digital tachograph (DTG). This information gathered using DTG can be utilized in various ways in the field of transportation. Notably in autonomous driving, the real-time analysis of this information can be used to prevent or respond to dangerous driving behavior. However, there is a limit to processing a large amount of data at a level suitable for real-time services using a traditional database system. In particular, due to a such technical problem, the processing of large quantity of traffic big data for real-time commercial vehicle operation information analysis has never been attempted in Korea. In order to solve this problem, this study optimized the new database server system and confirmed that a real-time service is possible. It is expected that the constructed database system will be used to secure base data needed to establish digital twin and autonomous driving environments.

• Journal of KIISE:Databases
• /
• v.30 no.2
• /
• pp.209-224
• /
• 2003

Recent development of electronic commerce enables the use of Electronic Stock Trading Systems(ESTS) to be expanded. In ESTS, information with various sensitivity levels is shared by multiple users with mutually different clearance levels. Therefore, it is necessary to use Multilevel Secure Database Management Systems(MLS/DBMSs) in controlling concurrent execution among multiple transactions. In ESTS, not only analytical OLAP transactions, but also mission critical OLTP transactions are executed concurrently, which causes it difficult to adapt traditional secure transaction management schemes to ESTS environments. In this paper, we propose Secure One Snapshot(SOS) protocol that is devised for Secure Transaction Management in ESTS. By maintaining additional one snapshot as well as working database SOS blocks covert-channel efficiently, enables various real-time transaction management schemes to be adapted with ease, and reduces the length of waiting queue being managed to maintain freshness of data by utilizing the characteristics of less strict correctness criteria. In this paper, we introduce the process of SOS protocol with some examples, and then analyze correctness of devised protocol.

• Journal of the Institute of Convergence Signal Processing
• /
• v.10 no.4
• /
• pp.256-261
• /
• 2009

While .NET and J2EE bisects recent distributed environment, .NET displays "Remoting" as a technology to call remote object. Remoting is frequently used as a protocol in OLTP's WEB program development in form of RPC that exchange data in XML form under HTTP environment. Purpose of this research is to draw problems when applying security to .NET remoting technology that is recently used in web programming, and to find effective application plan by implementing. The main discussion is following. First, network layer security should be replaced to application layer security for better performance and flexibility. Second, the serialization procedure that is repeated in both remoting and encryption module should take place once. Lastly, implementation of "Surrogate" and "Compress" will be discussed that enables to eliminate unnecessary data(table relations, keys, etc) that is used in dataset object of .NET in order to reduce the size of data. It is possible to achieve improvement in speed by two times through immediate implementation in these cases. In order for easier use, component based framework should be supplied hereafter.

• The KIPS Transactions:PartD
• /
• v.11D no.4
• /
• pp.747-754
• /
• 2004

Database administrators should be aware of performance characteristics of database systems in order to manage database system effectively. The usages of system resources in database systems could be quite different under database workloads. The objective of this paper is to identify and analyze performance characteristics of database systems in different workloads, which could help database tuners tune database systems Under the TPC-C and TPC-W workloads, which represent typical workloads of online transaction processing and electronic commerce respectively, we investigated usage types of resource that are determined by fourteen performance indicator, and are behaved in response to changes of four tuning parameters (data buffer, private memory, I/O process, shared memory). Eight out of the fourteen performance indicators cleary show the performance differences under the workloads. Changes of data buffer parameter give a influences to database system. The tuning parameter that affects the system performance significantly is the database buffer size in the both workloads.

• KIPS Transactions on Computer and Communication Systems
• /
• v.11 no.12
• /
• pp.419-428
• /
• 2022

Since in-place updates for pages are not allowed in flash memory, all new page writes should be written in an out-of-place manner. The old overwritten pages are invalidated. Such invalidated pages eventually trigger the costly garbage collection process. Since the garbage collection causes numerous read and write operations, it is one of the flash memory's major performance issues. In 2R, it modified the garbage collection algorithm, which applies the I/O characteristics of the On-Line Transaction Process workload to improve the Write Amplification Factor. However, this algorithm has a region pollution problem. Therefore, in this paper, we developed 2R++ that additionally separates pages with long access intervals to solve the region pollution problem. 2R++ introduces an extra bit per block to separate warm pages based on a second chance mechanism. Prevents warm pages from being misidentified as cold pages to solve region pollution problem. We conducted the experiments on TPC-C and Linkbench to make the performance comparison. The experiment showed that 2R++ achieved a Write Amplification Factor improvement of 57.8% and 13.8% compared to 2R, respectively.

• The KIPS Transactions:PartD
• /
• v.10D no.3
• /
• pp.407-416
• /
• 2003

As the usage of database systems dramatically increases and the amount of data pouring into them is massive, the performance administration techniques for using database systems effectively are getting more important. Especially in data warehouses, the performance management is much more significant mainly because of large volume of data and complex queries. The objectives and characteristics of data warehouses are different from those of other operational systems so adequate techniques for performance monitoring and tuning are needed. In this paper we extend functionalities of the DBMax, a performance administration tool for Oracle database systems, to apply it to data warehouse systems. First we analyze requirements based on summary management and ETL functions they are supported for data warehouse performance improvement in Oracle 9i. Then, we design architecture for extending DBMax functionalities and implement it. In specifics, we support SQL tuning by providing details of schema objects for summary management and ETL processes and statistics information. Also we provide new function that advises useful materialized views on workload extracted from DBMax log files and analyze usage of existing materialized views.