• 반도체디스플레이기술학회지
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• 제19권3호
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• pp.112-117
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• 2020

NAND flash memory is a non-volatile memory that retains stored data even without power supply. Internal memory used as a data storage device and solid-state drive (SSD) is used in portable devices such as smartphones and digital cameras. However, NAND flash memory carries the risk of electric shock, which can cause errors during read/write operations, so use error correction codes to ensure reliability. It efficiently recovers bad block information, which is a defect in NAND flash memory. BBT (Bad Block Table) is configured to manage data to increase stability, and as a result of experimenting with the error correction code algorithm, the bit error rate per page unit of 4Mbytes memory was on average 0ppm, and 100ppm without error correction code. Through the error correction code algorithm, data stability and reliability can be improved.

• International Journal of Internet, Broadcasting and Communication
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• 제13권3호
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• pp.104-108
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• 2021

In order to improve performance in IoT, edge computing system, a memory is usually configured in a hierarchical structure. Based on the distance from CPU, the access speed slows down in the order of registers, cache memory, main memory, and storage. Similar to the change in performance, energy consumption also increases as the distance from the CPU increases. Therefore, it is important to develop a technique that places frequently used data to the upper memory as much as possible to improve performance and energy consumption. However, the technique should solve the problem of cache performance degradation caused by lack of spatial locality that occurs when the data access stride is large. This study proposes a technique to selectively place data with large data access stride to a software-controlled cache. By using the proposed technique, data spatial locality can be improved by reducing the data access interval, and consequently, the cache performance can be improved.

• 반도체디스플레이기술학회지
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• 제11권2호
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• pp.85-91
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• 2012

In this paper, the large data processing and suitable FAT32 file system for industrial system using a PLC and CF memory was implemented. Most of PLC can't save the large data in user data memory. So it's required to the external devices of CF memory or NAND flash memory. The CF memory is used in order to save the large data of PLC system. The file system using the CF memory is NTFS, FAT, and FAT32 system to configure in various ways. Typically, the file system which is widely used in industrial data storage has been implemented as modified FAT32. The conventional FAT 32 file system was not possible for multiple writing and high speed data accessing. The proposed file system was implemented by the large data processing module can be handled that the files are copied at the 40 bytes for 1msec speed logging and creating 8 files at the same time. In a sudden power failure, high reliability was obtained that the problem was solved using a power fail monitor and the non-volatile random-access memory (NVSRAM). The implemented large data processing system was applied the modified file system as FAT32 and the good performance and high reliability was showed.

• Journal of Information Technology Applications and Management
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• 제11권1호
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• pp.189-200
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• 2004

Recently Flash Memory which is small and low-powered is widely used as a storage of embedded system, because an embedded system requests portability and a fast response. To resolve a difference of access time between a storage and RAM, Linux is using disk caching which copies a part of file on disk into RAM. It is not also an exception on embedded system. A READ access-time of flash memory is similar to RAMs. So, when a process on an embedded system reads data, it is similar to the time to access cached data in RAM and to access directly data on a flash memory. On the embedded system using limited memory, using a disk cache is that wastes much time and memory spaces to manage it and can not reflects the characteristic of a flash memory. This paper proposes the regular file access of limited using a page cache in the file system based on a flash memory and reflects the characteristic of a flash memory. The proposed algorithm minimizes power consumption because access numbers of the RAM are reduced and doesn't waste a memory space because it accesses directly to a flash memory Therefore, the performance improvement of the system applying the proposed algorithm is expected.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2003년도 가을 학술발표논문집 Vol.30 No.2 (1)
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• pp.196-198
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• 2003

Virtually every digital signal processors(DSPs) support on-chip multi- memory banks that allow the processor to access multiple words of data from memory in a single instruction cycle. Also, all existing fixed-point DSPs have irregular architecture of heterogeneous register which contains multiple register files that are distributed and dedicated to different sets of instructions. Although there have been several studies conducted to efficiently assign data to multi-memory banks, most of them assumed processors with relatively simple, homogeneous general-purpose resisters. Therefore, several vendor-provided compilers fer DSPs were unable to efficiently assign data to multiple data memory banks. thereby often failing to generate highly optimized code fer their machines. This paper presents an algorithm that helps the compiler to efficiently assign data to multi- memory banks. Our algorithm differs from previous work in that it assigns variables to memory banks in separate, decoupled code generation phases, instead of a single, tightly-coupled phase. The experimental results have revealed that our decoupled algorithm greatly simplifies our code generation process; thus our compiler runs extremely fast, yet generates target code that is comparable In quality to the code generated by a coupled approach

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.69-72
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• 2007

No doubt that more vast data and precise values are required for the detailed and accurate analysis result. People's expectation for the output of space application goes higher, and consequently satellite memory system has to process massive data faster. This paper reviews memory systems of KOMPSAT (Korea Multi-Purpose SATellite) series and try to find a suitable memory system structure to process data more faster not at device level but at system level.

• International Journal of Internet, Broadcasting and Communication
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• 제12권1호
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• pp.90-94
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• 2020

Artificial intelligence (AI) is software that learns large amounts of data and provides the desired results for certain patterns. In other words, learning a large amount of data is very important, and the role of memory in terms of computing systems is important. Massive data means wider bandwidth, and the design of the memory system that can provide it becomes even more important. Providing wide bandwidth in AI systems is also related to power consumption. AlphaGo, for example, consumes 170 kW of power using 1202 CPUs and 176 GPUs. Since more than 50% of the consumption of memory is usually used by system chips, a lot of investment is being made in memory technology for AI chips. MRAM, PRAM, ReRAM and Hybrid RAM are mainly studied. This study presents various memory technologies that are being studied in artificial intelligence chip design. Especially, MRAM and PRAM are commerciallized for the next generation memory. They have two significant advantages that are ultra low power consumption and nearly zero leakage power. This paper describes a comparative analysis of the four representative new memory technologies.

• 스마트미디어저널
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• 제4권3호
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• pp.16-23
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• 2015

IT 기술의 발전으로 인해 데이터 처리 시스템은 많은 양의 데이터를 처리 및 가공해야 한다. 하지만, 기존에 사용되던 온디스크(On-Disk) 시스템으로는 급증하는 데이터를 빠르게 처리하는 데 한계점을 가졌다. 이로 인해 많은 분야에서 하드디스크에 데이터를 저장하는 것이 아닌 속도가 빠른 메모리에 데이터를 저장 및 관리하는 인메모리(In-Memory) 시스템이 도입되고 있다. 하지만, 메모리에 데이터를 관리하는 것은 메모리의 특성 중 하나인 휘발성으로 인해 데이터 손실이라는 위험을 갖기 때문에 항상 결함 허용 기법이 뒤따라야 한다. 결함 허용 기법은 인메모리 시스템의 처리 속도를 낮추는 성능 저하 원인이 된다. 따라서 본 논문에서는 인메모리 시스템의 데이터 사용 특성을 고려하여 핫콜드 데이터로 분류하고, 데이터 영속성 보장을 위한 복합 백업 기법을 제안한다. 제안하는 기법은 영속성을 높이고, 성능 저하 원인을 보완한다.

• 반도체디스플레이기술학회지
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• 제19권3호
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• pp.118-123
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• 2020

In this paper, the design method of asynchronous nonvolatile memory module that can efficiently process and store large amounts of data without loss when the power turned off is proposed and implemented. PSRAM, which takes advantage of DRAM and SRAM, was used for data processing, and NAND flash memory was used for data storage and backup. The problem of a lot of signal interference due to the characteristics of memory devices was solved through PCB design using high-density integration technology. In addition, a boost circuit using the super capacitor of 0.47F was designed to supply sufficient power to the system during the time to back up data when the power is off. As a result, an asynchronous nonvolatile memory module was designed and implemented that guarantees reliability and stability and can semi-permanently store data for about 10 years. The proposed method solved the problem of frequent data loss in industrial sites and presented the possibility of commercialization by providing convenience to users and managers.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.694-698
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• 2004

In this paper, as one of these efforts for making the intelligent data mining system we propose the Associative frame of the memory according to the following three steps. First,the structured frame for performing the main brain function should be made. In this frame, the concepts of learning memory and episode memory are considered. Second,the learning mechanism for data acquisition and storing mechanism in the memory frame are provided. The obtained data are arranged and stored in the memory following the rules of the structured memory frame. Third, it is the last step of processing the inference and knowledge retrieval function using the stored knowledge in the associative memory frame. This system is applied to the area for estimating the purchasing degree from the type of customer's tastes, the pattern of commodities and the evaluation of a company.