• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.133-136
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• 2002

This paper presents a new method of Huffman decoding which gives a significant improvement of processing efficiency based on the reconstruction of an efficient one-dimensional array data structure incorporating the numeric interpretation of the accrued codewords in the binary tree. In the Proposed search method, the branching address is directly obtained by the arithematic operation with the incoming digit value eliminating the compare instruction needed in the binary tree search. The proposed search method gives 30% of improved Processing efficiency and the memory space of the reconstructed Huffman table is reduced to one third compared to the ordinary ‘compare and jump’ based binary tree. The experimental result with the six MPEG-2 AAC test files also shows about 198% of performance improvement compared to those of the widely used conventional sequential search method.

• 정보처리학회 논문지
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• 제13권7호
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• pp.311-318
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• 2024

인공지능과 인터넷의 발전으로 인한 데이터의 증가로 데이터 관리의 중요성이 부각되고 있는 상황에서, 데이터 검색과 메모리 공간의 효율적 활용이 매우 중요한 시대가 도래하였다. 본 연구에서는 메타데이터를 기반으로 데이터 구조를 분석하여 검색 속도와 메모리 효율을 최적화하는 방안을 연구한다. 연구방법으로는 사진 이미지의 메타데이터를 활용하여 배열, 연결리스트, 딕셔너리, 이진 트리, 그래프의 데이터 구조에 대한 성능을 시간적, 공간적 복잡도를 중심으로 비교하고 분석하였다. 실험을 통해 대규모의 이미지 데이터를 다루는 상황에서 딕셔너리 구조는 수집속도에서, 그래프 구조는 검색 속도에서 가장 우수한 성능을 보여주는 것을 확인할 수 있었다. 본 논문의 결과는 이미지 데이터 검색 속도와 메모리 효율을 최적화하기 위한 데이터 구조를 선택하는데 실용적인 가이드라인을 제시할 것으로 기대한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권7호
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• pp.3699-3719
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• 2017

Conjunctive keyword search encryption is an important technique for protecting sensitive personal health records that are outsourced to cloud servers. It has been extensively employed for cloud storage, which is a convenient storage option that saves bandwidth and economizes computing resources. However, the process of searching outsourced data may facilitate the leakage of sensitive personal information. Thus, an efficient data search approach with high security is critical. The multi-user search function is critical for personal health records (PHRs). To solve these problems, this paper proposes a novel multi-user conjunctive keyword search scheme (mNCKS) without a secure channel against keyword guessing attacks for personal health records, which is referred to as a secure channel-free mNCKS (SCF-mNCKS). The security of this scheme is demonstrated using the Decisional Bilinear Diffie-Hellman (DBDH) and Decision Linear (D-Linear) assumptions in the standard model. Comparisons are performed to demonstrate the security advantages of the SCF-mNCKS scheme and show that it has more functions than other schemes in the case of analogous efficiency.

• 한국정보통신학회논문지
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• 제24권1호
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• pp.44-49
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• 2020

최근 조선해양의 주요 이슈 중 하나는 선박의 대기 및 해양 오염 배출량 감소 문제이다. 이에 대하여 국제해사기구(IMO)에서는 선박으로 부터의 오염방지를 위한 국제협약(MARPOL)을 체결하고, 부속서 6을 통해 선박의 배기가스에 포함된 대기와 해양의 오염을 제한하고 규제하고 있다. 이를 위해 조선사의 신규 선박 건조에 대해서는 에너지 효율 설계 지수(EEDI)를 적용하고, 운항중인 선박에 대해서는 에너지 효율 운항 지표(EEOI)를 적용을 권고함으로써 환경오염물질의 배출을 최소화하도록 하고 있다. 이에 본 연구는 운항중인 선박의 실제 항해 데이터를 기반으로 선박의 운항 효율 등급(EG)을 산출하고, 해양환경 데이터 분석을 통해 에너지 효율적인 최적항로 탐색 정보를 제안하고자 한다.

• International Journal of Internet, Broadcasting and Communication
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• 제15권2호
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• pp.22-30
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• 2023

The portable mobile devices with high performance and high speed 5G network activate and explode the demands for ubiquitous information services that remove the limitations of time for the communication and places to request for the information. NN (Nearest Neighbor) search is one of the most important types of queries to be processed efficiently in the information services. Various indexes have been proposed to support efficient NN search in the wireless broadcast system. The indexes adopting Hilbert curve, grid partition or Voronoi diagram enable the clients to search for NN quickly in the wireless broadcast channel. It is necessary that an efficient means to evaluate the performances of various indexes. In this paper, we propose an open framework that can adopt a variety of indexing schemes and evaluate and compare the performances of them. The proposed framework is organized with open and flexible structure that can adopt hybrid indexing schemes extensible to Voronoi diagram as well as simple indexing schemes. With the implemented framework, we demonstrate the efficiency and scalability and flexibility of the proposed framework by evaluating various indexing schemes for NN query.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅳ
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• pp.2044-2047
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• 2003

In this paper, we propose efficient motion vector refinement algorithm for frame-rate reduction transcoding. The proposed algorithm is to set the search range for motion refinement based on the incoming motion vector. The algorithm calculates the importance of motion vector of the skipped frame and then selects two motion vector to set search range. Through this process, we determine the accuracy of incoming motion vector and set the search range lot refinement adaptively by means of the accuracy. In experiments, we show efficiency of our algorithm to reduce the search points for refinement.

• 정보관리연구
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• 제26권2호
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• pp.61-79
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• 1995

정보검색의 성공여부는 적절한 검색어의 선정에 달려있다고 해도 과언이 아니다. 특히 CD-ROM이나 온라인목록시스템에서 주제검색시 분류표, 주제명과 같은 통제어와 자연어 등 비통제어의 비교 우위 문제는 아직도 논란이 되고 있다. 본고는 두 시스템의 검색효율성을 비교하기 위하여 특히 다언어 환경하에서의 검색어 사용에 중점을 두고 다양한 형태의 검색어휘를 조사 분석하였다.

• 한국통신학회논문지
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• 제40권12호
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• pp.2485-2487
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• 2015

해시태그는 현재 페이스북, 트위터와 같은 SNS와 개인 블로그 등에서 활발하게 사용되고 있다. 하지만 스팸성 목적 또는 게시글 조회수 증가 등의 목적으로 무분별하게 해시태그를 사용하여 태그검색의 효율성이 떨어지고 있다. 이에 따라 본 논문에서는 태그검색의 정확도를 높이고자 기존의 키워드 추출 알고리즘과 단어간 유사도 평가 알고리즘을 이용한 태그 검색 시스템을 제안하였다. 제안하는 시스템의 테스트 결과 태그 검색의 정확도가 향상됨을 알 수 있었다.

• Journal of Information Processing Systems
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• 제14권5호
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• pp.1195-1214
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• 2018

Typical search engines may not be the most efficient means of returning images in accordance with user requirements. With the help of semantic web technology, it is possible to search through images more precisely in any required domain, because the images are annotated according to a custom-built ontology. With appropriate annotations, a search can then, return images according to the context. This paper reports on the design of a tourism ontology relevant to touristic images. In particular, the image features and the meaning of the images are described using various properties, along with other types of information relevant to tourist attractions using the OWL language. The methodology used is described, commencing with building an image and tourism corpus, creating the ontology, and developing the search engine. The system was tested through a case study involving the western region of Thailand. The user can search specifying the specific class of image or they can use text-based searches. The results are ranked using weighted scores based on kinds of properties. The precision and recall of the prototype system was measured to show its efficiency. User satisfaction was also evaluated, was also performed and was found to be high.

• Journal of Information Processing Systems
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• 제18권2호
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• pp.188-196
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• 2022

Recently, neural architecture search (NAS) has received increasing attention as it can replace human experts in designing the architecture of neural networks for different tasks and has achieved remarkable results in many challenging tasks. In this study, a path-based computation neural architecture encoder (PCE) was proposed. Our PCE first encodes the computation of information on each path in a neural network, and then aggregates the encodings on all paths together through an attention mechanism, simulating the process of information computation along paths in a neural network and encoding the computation on the neural network instead of the structure of the graph, which is more consistent with the computational properties of neural networks. We performed an extensive comparison with eight encoding methods on two commonly used NAS search spaces (NAS-Bench-101 and NAS-Bench-201), which included a comparison of the predictive capabilities of performance predictors and search capabilities based on two search strategies (reinforcement learning-based and Bayesian optimization-based) when equipped with different encoders. Experimental evaluation shows that PCE is an efficient encoding method that effectively ranks and predicts neural architecture performance, thereby improving the search efficiency of neural architectures.