• 한국광학회:학술대회논문집
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• 한국광학회 2000년도 제11회 정기총회 및 00년 동계학술발표회 논문집
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• pp.56-57
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• 2000

In this paper, DFE with feedforward section(FDFE) is used to mitigate ISI and improve BER generated in the course of storage and retrieval of high-density 2-dimensional data in digital holographic memory system. From the result of experiment, BER performance of DFE with feedforward section is improved about 37% than binary-decision course by direct thresholding.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1998년도 The Third Asian Fuzzy Systems Symposium
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• pp.240-245
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• 1998

Fuzzy information retrieval which uses the concept of fuzzy relation is able to retrieve documents in the way based on not morphology but semantics, dissimilar to traditional information retrieval theories. Fuzzy information retrieval logically consists of three sets : the set of documents, the set of terms and the set of queries. It maintains a fuzzy relational matrix which describes the relationship between documents and terms and creates a thesaurus with fuzzy relational product. It also provides the user with documents which are relevant to his query. However, there are some problems on building a thesaurus with fuzzy relational product such that it has big time complexity and it uses fuzzy values to be processed with flating-point. Actually, fuzzy values have to be expressed and processed with floating-point. However, floating-point operations have complex logics and make the system be slow. If it is possible to exchange fuzzy values with binary values, we could expect sp eding up building the thesaurus. In addition, binary value expressions require just a bit of memory space, but floating -point expression needs couple of bytes. In this study, we suggest a new method of building a thesaurus, which accelerates the operation of the system by pre-applying an ${\alpha}$-cut. The experiments show the improvement of performance and reliability of the system.

• Structural Engineering and Mechanics
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• 제17권3_4호
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• pp.331-346
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• 2004

A new sensor system is proposed for measuring damage indexes. The damage index is a physical value that is well correlated to a critical damage in a device or a structure. The mechanism proposed here utilizes elastic buckling of a thin wire and does not require any external power supply for memorizing the index. The mechanisms to detect peak strain, peak displacement, peak acceleration and cumulative deformation as examples of damage indexes are presented. Furthermore, passive and active wireless data retrieval mechanisms using electromagnetic induction are proposed. The passive wireless system is achieved by forming a closed LC circuit to oscillate at its natural frequency. The active wireless sensor can transmit the data much further than the passive system at the sacrifice of slightly complicated electric circuit for the sensor. For wireless data retrieval, no wire is needed for the sensor to supply electrical power. For the active system, electrical power is supplied to the sensor by radio waves emitted from the retrieval system. Thus, external power supply is only needed for the retrieval system when the retrieval becomes necessary. Theoretical and experimental studies to show excellent performance of the proposed sensor are presented. Finally, a prototype damage index sensor installed into a 7 storey base-isolated building is explained.

• 인터넷정보학회논문지
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• 제3권2호
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• pp.1-13
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• 2002

최근 인터넷 지리정보시스템에 대한 요구가 증가하면서 효율적인 공간 데이터 검색에 대한 필요성이 커지고 있다. 효율적인 공간 데이터 검색을 위해서는 단계별로 상세 화된 데이터를 검색하는 기법이 요구되며, 이러한 데이터를 효율적으로 처리하는 공간 인덱싱 기법이 필요하다. 본 논문에서는 효율적인 공간 데이터 검색을 위한 단계화 된 지리정보 데이터 검색을 지원하는 공간 인덱싱 기법을 제안한다. 기존의 공간 인덱싱 기법은 단계별 데이터를 검색하는데 비효율적이며, 단계별 데이터를 지원하는 몇 가지 공간 인덱싱 기법도 모든 종류의 단계별 데이터를 지원할 수 없는 문제점을 가진다. 제안된 구조는 모든 종류의 단계별 데이터를 지원하며, 메모리 용량과 검색 시간 모두에서 이전의 공간 인덱싱 기법보다 우수하다.

• International Journal of Contents
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• 제3권3호
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• pp.1-5
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• 2007

The main memory DBMS (MMDBMS) efficiently supports various database applications that require high performance since it employs main memory rather than disk as a primary storage. An index manager is an essential sub-component of a DBMS used to speed up the retrieval of objects from a large volume of a database in response to a certain search condition. Previous research efforts on indexing proposed various index structures. However, they hardly dealt with the practical issues occurred in implementing an index manager on a target DBMS. In this paper, we touch these issues and present our experiences in developing the index manager. The main issues are (1) compact representation of an index entry, (2) support of variable-length keys. (3) support of multiple-attribute keys, and (4) support of duplicated keys.

• 재활치료과학
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• 제4권2호
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• pp.73-83
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• 2015

목적 : 본 연구는 오차배제훈련을 병행한 시간차회상훈련이 경도인지장애(Mild Cognitive Impairment; MCI) 환자의 기억력에 미치는 효과와 수단적 일상생활(Instrumental Activities of Daily Living; IADL) 및 우울에 미치는 영향을 알아보고자 하였다. 연구방법 : 주간보호시설에 등록된 78세 MCI 노인을 대상으로 단일 대상 실험 연구 중 ABA 설계를 사용하여 실험을 진행하였다. 연구를 진행한 총 16회기 중 기초선 A는 총 3회기, 중재기간 B는 총 10회기, 기초선 A'는 총 3회기였다. 기억력을 측정하기 위한 회기별 평가로 Rey-Kim 언어 기억 검사(K-Auditory Verbal Learning Test; K-AVLT)를 사용하였고, 인지기능, IADL 수행 능력, 우울을 측정하기 위하여 각각 한국판 몬트리올 인지평가(Korean version of Montreal Cognitive Assessment; MoCA-K), 필라델피아 노인 센터 IADL 도구(Philadelphia Geriatric Center Instrumental Activities Daily Living; PGC IADL), 한국판 노인우울척도(Geriatric Depression Scale Korean Version; GDS-K)를 사용하였다. 결과 : 대상자는 기초선 A기간에 비하여 중재를 제공한 B기간에서의 즉시회상 및 지연회상이 현저히 증가하였다. 또한, 즉시회상과 지연회상 모두 B 기간에서 증가하던 측정값의 경향이 중재를 제거한 후인 기초선 A'구간에서 감소하는 경향을 보였다. MoCA-K 점수는 향상을 보였으며, PGC IADL 점수는 중재 전과 후가 같았고 GDS-K의 점수는 감소하였다. 결론 : 본 연구의 결과를 통하여 MCI 환자를 대상으로 실시한 오차배제훈련을 병행한 시간차 회상훈련의 근거를 확고히 하였다. 나아가 MCI 환자들이 기억력과 함께 어려움을 겪는 요인을 향상시키기 위한 중재 및 기억력과 다른 기능적 요소들에 대한 상관관계에 대하여 추가적인 연구가 필요할 것이다.

• 동의생리병리학회지
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• 제19권2호
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• pp.434-440
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• 2005

This study was conducted to find out the effect of Bojungikgitanggamibang(BIT) on growth, learning and memory of rats. The effects of BIT on learning and memory performance were examined in normal or memory impaired mice by using water maze task. Memory was impaired by 192 saporin. Body weight and growth of bone and tail of sample group were not significant compared with those of control groups. Acquisition test of water maze revealed that acqusitive ability of sample group significantly improved on 4,5th day compared with control group, while retentive ability of sample group was not significant. ChAT cell numbers of medial septum of sample group was significant compared with control group, and so was those of CA1, CA2 parts of hippocampus. On ChAT cell numbers of hippocampus, in CA2 part. These results suggest that BIT has an improving effect on the impaired learning through the effects on memory registration and retrieval.

• 반도체디스플레이기술학회지
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• 제18권4호
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• pp.57-61
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• 2019

Nowadays, portable digital cameras such as smart phone cameras are being popularly used for entertainment and visual information recording. Given a database of geo-tagged images, a visual location recognition system can determine the place depicted in a query photo. One of the most common visual location recognition approaches is the bag-of-words method where local image features are clustered into visual words. In this paper, we propose a new bag-of-words-based visual location recognition algorithm using time-series streetview database. The proposed algorithm selects only a small subset of image features which will be used in image retrieval process. By reducing the number of features to be used, the proposed algorithm can reduce the memory requirement of the image database and accelerate the retrieval process.

• 약학회지
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• 제36권1호
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• pp.56-65
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• 1992

The present study examined the effects of carbon monoxide (CO) intoxication and aging on learning and memory deficit in young($5{\sim}8$ weeks) and aged($52{\sim}66$ weeks) mice, using the step down and step through passive avoidance failure techniques. We also investigated the effects of ginseng saponins on memory deficit. Significant decrease in memory registration, retention and retrieval function in young mice and decrease in memory registration and retention function in aged mice were observed. Normal young mice were apt to perform to a great degree of passive avoidance response than normal aged mice, but there was no difference between both groups by CO exposure. Administration of ginseng saponins showed an improvement on passive avoidance failure induced by CO exposure.

• 대한전자공학회논문지SP
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• 제40권1호
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• pp.28-33
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• 2003

본 논문에서는 동영상 압축 부호화에 대한 표준안인 MPEG 기반의 압축 비디오 스트림으로부터 DCT DC 계수를 추출하구 이들로 구성된 DE 영상으로부터 장면 전환 검출을 수행한 후 대표 프레임을 추출한다. 또한 추출된 대표 프레임을 PCA(Principal Component Analysis) 방법을 이용하여 데이터베이스의 색인 정보로 저장한 후 입력된 질의 영상과 가장 유사한 대표 영상들을 검색하는 방법에 대해 제안한다. 즉, 추출된 대표 프레임에 대해 주성분해석 기법을 적용하여 통계적인 특성을 가진 데이터를 특징으로 추출함으로써 코드워드의 수에 따른 코드북을 생성하고 이를 데이터베이스의 색인 정보로 저장한다. 실험 결과 제안된 방법이 검색에 있어 우수한 성능을 나타내고 또한 통계적인 데이터의 특성을 이용하기 때문에 처리 시간과 상당한 양의 메모리 공간을 줄일 수 있음을 확인하였다.