• The KIPS Transactions:PartD
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• v.10D no.2
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• pp.187-194
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• 2003

Main Memory storage system can increase the performance of the system by assigning enough slack time to real-time transactions. Due to its high response time of main memory devices, main memory resident data management systems have been used for location management of personal mobile clients to cope with urgent location related operations. In this paper we have developed a multi-threaded main memory storage system as a core component of real-time retrieval system to handle a huge amount of readers and writers of main memory resident data. The storage system is implemented as an embedded component which is working with the help of a disk resident database system. It uses multi-threaded executions and utilizes latches for its concurrency control rather than complex locking method. It only saves most recent data on main memory and data synchronization is done only when disk resident database asks for update transactions. The system controls the number of read threads and update threads to guarantee the minimum requirements of real-time retrievals.

• Proceedings of the IEEK Conference
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• 2003.07d
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• pp.1283-1286
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• 2003

Human can update the memory with new information not forgetting acquired information in the memory. ART(Adaptive Resonance Theory) does not need to change all information. The methodology of ART is followed. The ART updates the memory with the new information that is unknown if it is similar with the memorized information. On the other hand, if it is unknown information the ART adds it to the memory not updating the memory with the new one. This paper shows that ART is able to classify sensory information of a certain object. When ART receives new information of the object as an input, it searches for the nearest thing among the acquired information in the memory. If it is revealed that new information of the object has similarity with the acquired object, the model is updated to reflect new information to the memory. When new object does not have similarity with the acquired object, the model register the object into new memory

• Journal of KIISE:Databases
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• v.31 no.1
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• pp.39-47
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• 2004

Spatio-temporal databases have been mostly studied in the area of access methods. However, without considering an extraordinary update maintenance overhead after building up a spatio-temporal index, most indexing techniques have focused on fast query processing only. In this paper, we propose an efficient update management method that reduces the number of disk accesses required in order to apply the updates of moving objects to a spatio-temporal index. We consider realistic update patterns that can represent the movements of objects properly. We present a memory based structure that can efficiently maintain a small number of very frequently updating objects. For an experimental environment with realistic update patterns, the number of disk accesses of our method is about 40% lower than that of a general update method of existing spatio-temporal indexes.

• Journal of Internet Computing and Services
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• v.13 no.3
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• pp.83-91
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• 2012

Recently, column-oriented storage has become a progressive model for high-speed database systems because of its superior I/O performance. In this paper, we analysis traditional raw-oriented storage model and then propose a new column-aware storage management model using flash memory drive and assist drive to improve the effective performance of the high-speed column-oriented database system. Our storage management scheme called column-aware polarization improves the performance of update operation by dividing and compressing table columns into active-columns or inactive-columns, and balancing congested update operations using a assist drive in high workload periods. The results obtained from experimental tests show that our scheme improves the update throughput of column-oriented storage by 19 percent, and the response time by up to 49 percent.

• Journal of the Korea Society of Computer and Information
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• v.18 no.4
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• pp.1-11
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• 2013

Dynamic Software Update(DSU) is a technique, which updates a new version of the software to a running process without stopping. Many DSU systems that update C application programs are introduced. However, these DSU systems differ in implementation method or in main features. In this paper, we propose a new DSU system that can solve some disadvantages of existing DSU systems. DSU system presented in this paper splits existing program to code, global data and local data and then updates each part of the program considering the characteristics of the respective parts. The proposed system in this paper is implemented and tested on Linux. Also, we compared our DSU system with other DSU systems and we could find some strength of our DSU system. First, the code memory usage of our DSU system can be efficient since our system does not need to maintain code of an old version. Second, the global data memory waste is small because our system does not need to allocate the global data again which is not modified in the new version. Finally, we restore local data of old version in stack area of the new version using stack reconstruction technique. This paper is meaningful since we proposed a new DSU method and we implemented a full DSU system using the method.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.269-272
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• 2001

Since Multi-way Search Tree reduces the number of the memory access by increasing the branch factor, it is considered a method to archive the high-speed IP address lookup. Using the combination of initial 16 bit may and Multi-way Search Tree, it also reduces the search time of If address lookup. Multi-way Search Tree consists of K keys and K＋1 key pointers. This paper shows how the E update of Multi-way Search Tree which consists of the one pointer within a node can be performed. Using the one pointer within a node, it increases the number of keys within a node and reduces the search time of IP lookup. We also describes IP updating methods such as modification, Insertion and Deletion of address entries. Our update scheme performs better than the method which rebuilds the entire IP routing table when IP update processes.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.4 no.4
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• pp.278-285
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• 2011

This paper makes an analysis of the encoding structure and the decoding algorithm proposed by the DVB-S2 specification. The methods of implementing the LDPC decoder are fully serial decoder, the partially parallel decoder and the fully parallel decoder. The partial parallel scheme is the efficient selection to achieve appropriate trade-offs between hardware complexity and decoding speed. Therefore, this paper proposed an efficient memory structure for check node update block, bit node update block, and LLR memory.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.2
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• pp.73-81
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• 2007

We give two weaknesses of a recently proposed streamcipher MICKEY. We show time-memory-data tradeoff is applicable. We also show that the state update function reduces entropy of the internal state as it is iterated, resulting in keystreams that start out differently but become merged together towards the end.

• Journal of Advanced Navigation Technology
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• v.14 no.5
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• pp.767-774
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• 2010

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.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.217-219
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• 2001

플래쉬 메모리는 데이터 저장 및 변경이 가능한 비휘발성 메모리로 가벼운 무게, 낮은 전력 소모, 충격에 대한 저항성과 빠른 데이터 처리 능력 때문에 이동형 컴퓨터 시스템에서 사용하기에 적당하다. 그러나 플래쉬 메모리는 덮어쓰기(update-in-place)가 불가능하고 각 메모리 셀에 대해 초기화 작업(erasing operation)의 수가 제한되어 있다. 이러한 단점들을 고려하여 세그먼트의 데이터 중 유효 데이터의 비율과 hot 데이터(가까운 시간 안에 update가 될 것이라는 예상되는 data)의 수, 세그멘트가 초기화되었던(easing) 횟수 등을 고려한 새로운 초기화 기법(cleaning policy)을 제안하고자 한다.