• Proceedings of the Korean Society of Computer Information Conference
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• 2014.07a
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• pp.227-229
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• 2014

플래시 메모리는 빠른 처리 속도, 비휘발성, 저 전력, 강한 내구성 등으로 인해 최근 스마트폰, 태블릿, 노트북, 컴퓨터와 같은 여러 분야에서 많이 사용하고 있다. 최근 기존에 사용하던 NAND 플래시가 미세화 기술의 한계에 봉착함에 따라 기존 2차원 구조의 NAND플래시를 대처할 장치로 3차원 수직구조 NAND 플래시 메모리(3D Vertical NAND)가 주목받고 있다. 기존의 플래시 메모리는 데이터를 효율적으로 삽입/삭제/검색하기 위해 B-tree와 같은 색인기법을 필요로 한다. 플래시 메모리 상에서 B-tree 구현에 관한 기존 연구로서는 BFTL(B-Tree Flash Translation Layer)기법이 최초로 제안되었다. 현재 3차원 V-NAND 구조의 플래시 메모리가 시작품으로 제작되어 머지않아 양산 될 예정이다. 본 논문에서는 향후 출시될 3차원 구조의 플래시 메모리에 적합한 Octree 기반의 파일시스템을 제안한다.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.9
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• pp.483-490
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• 2005

Recently, flash memory is widely used in embedded applications since it has strong points: non-volatility, fast access speed, shock resistance, and low power consumption. However, due to its hardware characteristics, it requires a software layer called FTL(flash translation layer). The main functionality of FTL is to convert logical addresses from the host to physical addresses of flash memory We present a new FTL algorithm called STAFF(State Transition Applied Fast Flash Translation Layer). Compared to the previous FTL algorithms, STAFF shows five times higher performance than basic block mapping scheme and requires less memory. We provide performance results based on our implementation of STAFF and previous FTL algorithms.

• International journal of advanced smart convergence
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• v.10 no.1
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• pp.142-150
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• 2021

Open-channel SSD is a new type of Solid-State Disk (SSD) that improves the garbage collection overhead and write amplification due to physical constraints of NAND flash memory by exposing the internal structure of the SSD to the host. However, the host-level Flash Translation Layer (FTL) provided for open-channel SSDs in the current Linux kernel consumes host memory excessively because it use page-level mapping table to translate logical address to physical address. Therefore, in this paper, we implemente a selective mapping table loading scheme that loads only a currently required part of the mapping table to the mapping table cache from SSD instead of entire mapping table. In addition, to increase the hit ratio of the mapping table cache, filesystem information and mapping table access history are utilized for cache replacement policy. The proposed scheme is implemented in the host-level FTL of the Linux kernel and evaluated using open-channel SSD emulator. According to the evaluation results, we can achieve 80% of I/O performance using the only 32% of memory usage compared to the previous host-level FTL.

• Korean Journal of Cognitive Science
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• v.14 no.1
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• pp.29-40
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• 2003

Cross-Language Information Retrieval (CLIR) deals with the documents in various languages by one language query. A user who uses one language can retrieve the documents in another language through CLIR system. In CLIR, query translation method is known to be more efficient. For the better performance of query translation, we need more resources like dictionary, ontology, and parallel/comparable corpus but usually not available. This paper proposes a new concept called the Common Base Axis which is adapted to Korean-English Query translation ann a new weighting method in dictionary based query translation. The essential idea is that we can express Korean and English word in one vector space by Common Base Axis and use it in calculating sense distance for query weighting. The experiments show that Common Base Axis gives us good performance without ontology and is especially good for one word query translation.

• Journal of the Korea Computer Industry Society
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• v.5 no.1
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• pp.39-48
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• 2004

An IP address shortage problem is happening with a rapid propagation of the Internet and demands about a new IP address. Address translation technology as NAT is becoming use widely in order to solve these problems. NAT is an very useful If address translation technique that allows two connected networks to use different and incompatible IP address schemes. Rut it is difficult to use NAT particularly for applications that embeded IP addresses in data payloads or encrypted IP packet to guarantee End-to-End Security such as IPSec. In addition to rewiting the source/destination IP address in the packet, NAT must modify IP checksum every time, which could lead to considerablely performance decrease of the overall system in the process of address translation. RSIP is an alternative to solve these disadvantages and address shortage problems of NAT. Both NAT and RSIP divide networks into inside and outside addressing realms. NAT translates addresses between internal network and external network, but RSIP uses a borrowed external address for outside communications. RSIP server assigns a routable, public address to an RSIP client temporaily to communicate with public network outside the private network. In this paper, I will analyze NAT and RSIP gateway system, and then I will propose the Linux-based RSIP gateway for more efficient IP Address Translation in Intranet environments based on RSIP standard of IETF.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.7
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• pp.108-118
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• 1994

By using a concept of interrelation vector between line segments a new algorithm for partial shape recognition of two-dimensional objects is introduced. The interrelation vector which is invariant under translation rotation and scaling of a pair of line segments is used as a feature information for polygonal shape recognition. Several useful properties of the interrelation vector are also derived in relation to efficient partial shape recognition. The proposed algorithm requires only small space of storage and is shown to be computationally simple and efficient.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.37 no.3
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• pp.1-11
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• 2000

An example-based machine translation approach is a new paradigm for resolving various problems caused by the rules of conventional rule-based machine translation. But, in pure example-based machine translation, it is very hard to find similar examples matched with input sentences by using reasonable parallel corpus. This problem causes large overheads in the process of sentence generation. This paper proposes new method of English-Korean transfer using both patterns and examples. The patterns are composed of sentence patterns and phrase patterns. Meta parts of the patterns make the example-based machine translation more practical by raising the probability to find similar examples. The use of patterns and examples can reduce the ambiguities in source language analysis and give us a high quality of MT. And experimental results with a test corpus are discussed.

• The KIPS Transactions:PartA
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• v.17A no.4
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• pp.173-180
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• 2010

To specify a formal semantics is to do a significant part for design, standardization and translation of programming languages. The existing studies of a formal semantics for Java have a weak point to describe a clear and practical semantics for an efficient translation. It is necessary to do research for a formal semantics to specify a static and dynamic semantics clearly in order to do an efficient translation. This paper presents the improved Action Equation that specifies a formal semantics for Java to extend the research using Action Equation. The Action Equation is a practical and accurate specification that describes object-oriented programming features and handles exceptions. The specified Action Equation is compared to other descriptions, in terms of readability, modularity, extensibility, and flexibility and then we verified that Action Equation is superior to other formal semantics.

• The Journal of the Korea Contents Association
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• v.8 no.6
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• pp.82-88
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• 2008

ARM processors are being utilized in a variety of embedded systems. It is also that most ARM processor accepts C application, and then generates ARM assembly code using GNU gcc Cross-compiler. For the purpose of improving the quality of code generated and the efficient code generation, the various researches are underway. In this paper, we generates the ARM assembly code from the ANSI C programs using Syntax-directed Translation Techniques, and then the performance evaluation results for our research experimental compare to GNU gcc Cross-compiler are described. The techniques are presented in this research compared to GNU gcc cross-compiler very simple and convenient in extension of the production rules.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.10
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• pp.1183-1192
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• 1988

In this paper, we describe heuristic information-added morphological dictionary and connection table, and automatic MUNJEUL separation process on the basis of least cost method for efficient morphological analysis. It is simplified the composition of connection and inflective word information by mutually interconnect conjugation table with connection tables. As a result, the applicability of system is increased. Translation dictionary consists of analysis and generation part and, increase the applicability by describing frequently using termination phrase which is extracted statistically as idiom and the procedure directly on the dictionary for the efficiency of analysis process and more natural generation of translation sentence.