다차원 색인구조를 위한 동시성제어 기법 및 회복기법

송석일,유재수,Song, Seok-Il,Yoo, Jae-Soo 한국정보처리학회 2003 정보처리학회논문지D Vol.10 No.2

이 논문에서는 다차원 색인구조의 동시성을 최대화하는 동시성제어 알고리즘과 이를 위한 회복기법을 제안한다. 다차원 색인구조에서 동시성을 저하는 가장 큰 요인은 MBR 변경연산과 분할 연산이다. 제안하는 알고리즘은 먼저 MBR 변경연산으로 인한 동시성 저하를 최소화하기 위해서 PLC(Partial Lock Coupling) 기법을 제안한다. 이 기법은 기존 방법에 비해 잠금결합을 사용하는 회수를 크게 줄여 동시성을 높인다. 또한, MBR 변경의 수행 중에도 탐색자들이 해당 노드를 접근할 수 있도록 하는 MBR 변경 방법을 제안한다. 분할로 인한 동시성 저하를 해결하기 위해서 노드 분할로 인한 탐색자의 지연 시간을 최소화 할 수 있는 새로운 분할방법을 제안한다. 제안하는 알고리즘을 BADA-4 DBMS의 저장시스템인 MiDAS-3에서 구현하여 성능평가를 수행한다. 다양한 실험을 통해 제안하는 방법이 기존 방법보다 우수함을 보인다. 마지막으로, 이 논문에서는 제안하는 동시성제어 방법에 적절한 회복기법을 제안한다. 회복기법은 동시성을 최대한 보장할 수 있도록 설계되었으며 빠른 회복시간을 보장한다. In this paper, we propose an enhanced concurrency control algorithm that maximizes the concurrency of multi-dimensional index structures. The factors that deteriorate the concurrency of index structures are node splits and minimum bounding region (MBR) updates in multi-dimensional index structures. The proposed concurrency control algorithm introduces PLC(Partial Lock Coupling) technique to avoid lock coupling during MBR updates. Also, a new MBR update method that allows searchers to access nodes where MBR updates are being performed is proposed. To reduce the performance degradation by node splits the proposed algorithm holds exclusive latches not during whole split time but only during physical node split time that occupies the small part of a whole split process. For performance evaluation, we implement the proposed concurrency control algorithm and one of the existing link technique-based algorithms on MIDAS-3 that is a storage system of a BADA-4 DBMS. We show through various experiments that our proposed algorithm outperforms the existing algorithm in terms of throughput and response time. Also, we propose a recovery protocol for our proposed concurrency control algorithm. The recovery protocol is designed to assure high concurrency and fast recovery.

한국어 음성인식을 위한 음소분할에 관한 연구 ( A Study on the Phoneme Segmentation Method for the Korean Languae Recognition )

송석일,한영일 한국통신학회 1986 한국통신학회 학술대회논문집 Vol.5 No.2

Disign of the Communication Protocol between Client and Server for MIDISK Based on Windows CE

송석일,곽윤식,김병주 한국정보기술학회 2006 한국정보기술학회논문지 Vol.4 No.1

The internet disk that this paper presents for mobile device makes a long-distanced storage recognized as a local storage. It goes beyond the established concept of saving the data of a distant area and down-loading or up-loading them into mobile device; assuming the storage of the distant area as a local storage of mobile device, this system makes the storage of the distant area available anywhere to the user. The MIDISK consists of designing parts of the protocol of internet disk for mobile device, the client, and the server. It was implemented by information device of Windows CE environment. For this purpose, we suggest the design of communication protocol between MIDISK client and server.

멀티미디어 이동체통신의 요소기술

송석일,정태진,Song, Seok-Il,Jeong, Tae-Jin 한국전자통신연구원 1996 전자통신동향분석 Vol.11 No.3

본 고에서는 멀티미디어 이동체 통신핵심 관련 기술분야인 멀티미디어 이동체통신을 위한 음성, 화상의 정보압축기술과 표준화동향에 대하여 서술하고, 개인이동통신의 무선액세스 기술과 개인이동통신을 지원하는 인텔리전트 네트워크의 개념에 따른 이동네트워크의 플렛폼화를 목표로 한 구조에 대하여 기술한다.

An Empirical Study on Supporting System for Agricultural Product Storage Technology

송석일,곽윤식 한국정보기술학회 2014 JOURNAL OF ADVANCED INFORMATION TECHNOLOGY AND CON Vol.4 No.1

Most of the existing agricultural product management systems based on ICT convergence are designed to trace the history of harvesting and distribution procedures or to monitor the growth process. ICT convergence management system needs to grow beyond the boundary of merely tracing the distribution history and monitoring growth environments; it should monitor environmental factors that affect agricultural products in the storage and distribution process, measure the level of deterioration based on the monitoring result, and thus reduce the rates of disposal due to quality deterioration. In addition, there should be a system to predict prices of agricultural products and to determine the best timing of sales so that farmers can sell goods at reasonable prices. This study relates the basic structure and functions of this system and presents the result of the empirical research project.

An Empirical Study on Agricultural Product Distribution Technology by Means of ICT Convergence

송석일,곽윤식 한국정보기술학회 2014 JOURNAL OF ADVANCED INFORMATION TECHNOLOGY AND CON Vol.4 No.1

When it comes to the high distribution cost ratio of agricultural products, the major causes include lack of competition among distribution channels and inefficiency of distribution steps in addition to inevitable aspects such as the large volume and weight compared to the price, distance between producers and consumers, advanced types of consumption, gradual decomposition, and natural spoilage, the last two of which are primary factors that increase the distribution cost ratio. In general, agricultural products are vulnerable to supply shock, and thus price fluctuation rates are higher than those of industrial products. In particular, vegetables and fruits, which are difficult to keep fresh for a long period of time and easily affected by weather conditions, are of high price fluctuation rates. For these reasons, it is of urgent need to come up with ways to minimize natural spoilage and disposal in distribution of agricultural products. The suggested system provides various functions : a function to predict weight reduction of products during the storage and distribution process based on the analysis of data collected by the server to judge the level of quality deterioration.

Dynamic Log Page Allocation Method for Flash Memory

송석일,길기정 한국정보기술학회 2011 JOURNAL OF ADVANCED INFORMATION TECHNOLOGY AND CON Vol.1 No.1

Due to advantages of NAND flash memory such as non-volatility, low access latency, low energy consumption, light weight, small size and shock resistance, it has become a better alternative over traditional magnetic disk drives, and has been widely used. Traditional DBMSs including mobile DBMSs may run on flash memory without any modification by using Flash Translation Layer (FTL), which emulates a random access block device to hide the characteristics of flash memory such as “erase-before-update”. However, most existing FTLs are optimized for file systems, not for DBMSs, and traditional DBMSs are not aware of them. Also, traditional DBMSs do not consider the characteristics of flash memory. In this paper, we propose a flash-conscious storage system for DBMSs that utilizes flash memory as a main storage medium, and carefully put the characteristics of flash memory into considerations. The proposed flash-conscious storage system exploits log records to avoid costly update operations. It is shown that the proposed storage system outperforms the state of the art flash-conscious DBMSs through the simulation.

Continuous Skyline Query on Sensor Network

송석일 한국정보기술학회 2011 JOURNAL OF ADVANCED INFORMATION TECHNOLOGY AND CON Vol.1 No.2

Data centric storages for sensor networks have been proposed to efficiently process multi-dimensional range queries as well as exact matches. Usually, a sensor network does not process only one type of the query but supports various types of queries such as range queries, exact matches and skyline queries. Therefore, a sensor network based on a data centric storage for range queries and exact matches should process skyline queries efficiently. However, existing algorithms for skyline queries have not considered the features of data centric storages. Some of the data centric storages store similar data in sensor nodes that are placed on geographically similar locations. Consequently, all data are ordered in a sensor network. In this paper, we propose a new skyline query processing algorithm that exploits the above features of data centric storages.

Survey on Seamless Migration Methods in Cloud Computing Environments

송석일 한국정보기술학회 2012 JOURNAL OF ADVANCED INFORMATION TECHNOLOGY AND CON Vol.2 No.2

Generally, in cloud platforms, multiple applications (tenants) are hosted in a single node and they show various load patterns that are not easy to predict. Also, since cloud platforms usually use pay-per-use policy, they should be able to minimize the operating cost. Consequently, elastic load balancing to scale up and down according to work load is the most important feature for cloud providers. A low cost live migration is the key technique for the elastic load balancing. Subsequently, many migration methods have been proposed. In this paper, we summarize them, and analyze them in terms of several aspects. Finally, we compare the methods and draw further research issues

B-NT 시스템의 클럭분배에 관한 연구 ( A Study of Clock Distribution Mechnism in the B-NT System )

송석일,정동범,김찬,최준균 대한전자공학회 1994 대한전자공학회 학술대회 Vol.1994 No.1