• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권5호
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• pp.1489-1515
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• 2022

The number of interconnected real-world devices such as sensors, actuators, and physical devices has increased with the advancement of technology. Due to this advancement, users face difficulties searching for the location of these devices, and the central issue is the findability of Things. In the WoT environment, keyword-based and geospatial searching approaches are used to locate these devices anywhere and on the web interface. A few static methods of indexing and ranking are discussed in the literature, but they are not suitable for finding devices dynamically. The authors have proposed a mechanism for dynamic and efficient searching of the devices in this paper. Indexing and ranking approaches can improve dynamic searching in different ways. The present paper has focused on indexing for improving dynamic searching and has indexed the Things Description in Solr. This paper presents the Things Description according to the model of W3C JSON-LD along with the open-access APIs. Search efficiency can be analyzed with query response timings, and the accuracy of response timings is critical for search results. Therefore, in this paper, the authors have evaluated their approach by analyzing the search query response timings and the accuracy of their search results. This study utilized different indexing approaches such as key-words-based, spatial, and hybrid. Results indicate that response time and accuracy are better with the hybrid approach than with keyword-based and spatial indexing approaches.

• 한국컴퓨터정보학회논문지
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• 제11권1호
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• pp.19-25
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• 2006

홍채인식은 개인의 홍채 패턴을 이용한 인식시스템으로 정보보안 분야나 개인 인증에 최고의 인증시스템중 하나로 알려져 있다. 홍채 인식을 위해 가장 먼저 해결해야하는 문제는 동공중심점탐색 이 매우 중요하다. 지금까지 많은 탐색 알고리즘들이 개발되었으나 대부분 처리시간이 매우 많이 소요된다. 본 논문에서는 새로운 동공 중심점 탐색 방법을 제시하고, Hough 변환을 이용한 방법과 비교하였다. 그 결과 120개의 이미지를 대상으로 실험한 결과 약 30%의 처리 속도 개선의 결과를 얻었다.

• 한국정보통신학회논문지
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• 제14권1호
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• pp.115-121
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• 2010

인터넷의 이용이 활발해짐에 따라 수많은 정보들이 웹을 통하여 공개되고 있으며, 이용자는 웹 검색 서비스를 이용하여 이러한 정보들에 효과적으로 접근할 수 있다. 웹 검색 서비스의 구축을 위해서는 웹 로봇을 사용한 웹 문서 수집이 선행되어야 하며, 웹 문서들의 수가 급격히 증가하면서 양질의 웹 문서들을 효과적으로 수집할 수 있는 웹 로봇에 대한 필요성이 증가되고 있으며, 그에 따른 많은 웹 수집 로봇이 탄생되고 있다. 본 논문에서는 효과적인 웹 수집 로봇의 설계와 동적인 웹페이지에서 사용하는 자바스크립트의 링크추출 방안을 제안하였다. 본 논문에서는 성능 분석을 위하여 제안된 모델을 사용하여 수집 모델을 1개로 설정해 놓고 299개의 웹 페이지를 점검 하였을 경우, 2분 12.67초가 소요되었고, 수집 모델을 10개로 생성하여 점검 하였을 경우 12.33초가 소요됨을 알 수 있었다.

• 한국통신학회논문지
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• 제30권9A호
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• pp.714-721
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• 2005

본 논문에서는 직교 주파수 분할 다중 접속/시 분할 다중화(OFDMA/TDD :OFDM-FDMA/ Time Division Duplexing) 시스템에서의 프리앰블 모델을 분석하고, AWGN과 ITU-R M.1225 Ped-B 및 Veh-A 채널 환경에서 OFDMA/TDD 시스템에 적용된 심볼 타이밍 및 반송파 주파수 오프셋 추정과 셀 탐색 성능을 모의 실험을 통하여 그에 따른 성능을 Detection Probability, False Alarm, Missing Probability, Mean Acqusition Time 및 (MSE) Mean Square Error 로 확인한다. 특히, 심볼 타이밍 오프셋 추정에서는 향상된 성능을 가지는 프리앰블 구조 및 알고리즘을 제안한 후, 기존의 프리앰블 구조와 그에 따른 성능을 비교 분석한다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.390-395
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• 2009

The robustness of audio fingerprinting system in a noisy environment is a principal challenge in the area of content-based audio retrieval. The selected feature for the audio fingerprints must be robust in a noisy environment and the computational complexity of the searching algorithm must be low enough to be executed in real-time. The audio fingerprint proposed by Philips uses expanded hash table lookup to compensate errors introduced by noise. The expanded hash table lookup increases the searching complexity by a factor of 33 times the degree of expansion defined by the hamming distance. We propose a new method to improve noise robustness of audio fingerprinting in noise environment using predominant pitch which reduces the bit error of created hash values. The sub-fingerprint of our approach method is computed in each time frames of audio. The time frame is transformed into the frequency domain using FFT. The obtained audio spectrum is divided into 33 critical bands. Finally, the 32-bit hash value is computed by difference of each bands of energy. And only store bits near predominant pitch. Predominant pitches are extracted in each time frames of audio. The extraction process consists of harmonic enhancement, harmonic summation and selecting a band among critical bands.

• 복식문화연구
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• 제21권1호
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• pp.129-138
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• 2013

Consumers' perception of risk plays a major role in how they make online purchase decisions. Since online shopping is perceived to be riskier than in-store shopping, consumers engage in a variety of risk reduction strategies such as searching online for alternative products and alternative e-tailers. This study examines the influence of risk involvement on risk reduction strategies and customer satisfaction. It discusses three aspects of risk reduction strategies: time spent in making a purchasing decision, searching for alternative e-tailers, and searching for alternative products. Data from 294 female shoppers who had experience in purchasing fashion products online was analyzed. This study found that risk involvement had a positive influence on the time spent in making decisions, while the influence of risk involvement on searching for alternative retailers and alternative products was not significant. However, consumer satisfaction was negatively related to search for alternative retailers and positively related to risk involvement. This study provides a better understanding of customers' risk involvement and risk reduction strategies in online shopping. This information would be beneficial for marketers and retailers to reduce customer perception of risks and to promote online sales.

• 한국통신학회논문지
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• 제19권4호
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• pp.740-749
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• 1994

본 논문에서는 기존의 PSELP음성 부호화기의 성능을 개선하는 방법들을 제안하였다. 혼합 방법에 의한 주기추출법을 제안하여 기존의 PSELP음성 부호화기의 피치 주기 탐색시간을 줄였으며, 장기 필터(long term filter)의 출력 여기신호에서의 양자화 오차로 인해 발생할 수 있는 주기추출 오류를 개선시켰다. 또한 주기성을 향상기키고 잡음을 줄이기위해 본 논문에서 제안한 주기성 향상 필터를 복호기의 여기신호에 적용하여으며, 합성된 음성신호에서 음의 명료도를 높이기 위해 적응 일차 필터를 적용하였다. 작시한 방식과 필터를 적용한 결과 주기탐색시간이 기존에 대해 26%로 줄었으며, 최종합성음의 MOS(mean opinion score) 측정기에서 기존함성음은 3.19를 나타낸데 비해 개선된 합성읍의 4.04를 나타내었다.

• 한국실내디자인학회논문집
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• 제25권5호
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• pp.71-81
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• 2016

This research has been carried out with the objects of sporting goods shops to find out what structure of those shops raises more interest from customers. The tracking eyes on the objects which are the same but seen to have different structures has revealed the followings. Customers' visual appreciation of Reverse left/right Images (11.1) was found to be higher than that of Original Images (10.6). Furthermore, the reverse left/right image of the space also was found to attract more interest from customers, which led them to have longer observation. The below is about the interpretation of the spatial exploration by observation time and the appreciation of its visual content in line with the experiment objects of selling spaces. The longer the space was observed, (1)the higher the expansive searching of space was, (2)the more spots were observed as if they did not know what to see after they first observed at early hours, (3)later (in the time range of 64~73 seconds) they came to look at the spots in which they got interested, (4)and then again they suddenly got lost what to see. When the change of observation characteristics by time range is reviewed, it can be seen that the searching of original images is changed from Divergent Feature to Convergent Feature when the observation time increases from the early stage of observation to the later. On the contrary, the reverse left/right images were found to have the opposite searching features, that is, from convergent exploration to divergent exploration. These findings show that the reverse left/right images of the sporting goods shops, which were the experiment objects, have more factors attracting customers' attention and interest and that it is the very shop-structure which makes customers have better visual appreciation of those shops.

• 한국문헌정보학회지
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• 제30권2호
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• pp.51-86
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• 1996

본 연구는 전문데이터베이스의 탐색에 있어서 주제전문가와 탐색전문가는 어떠한 특징적인 차이가 있는지를 밝히려 하였다. 이 연구를 통하여 얻어진 결론을 요약하면, 주제전문가와 탐색전문가는 전문데이터베이스의 탐색에, 있어서 탐색질문의 분석(탐색질문의 이해도. 탐색어 선정의 난이도, 탐색결과에 대한 기대수준), 탐색과정(탐색어수, 연산자 순 브라우징 문헌 순 접속시긴 출력문헌 건당 소요시긴 적합문헌 건당 소요시간), 탐색결과 (적합문헌수 재현율 정확율, 총 탐색비용 출력문헌 건당 소요비용, 적합문헌 건당 소요비용, 탐색결과에 대한 만족도)에 대하여 뚜렷한 차이를 나타내는 것으로 밝혀졌다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.31-34
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• 1999

In this paper, the improved initial cell searching algorithm is proposed for 3GPP W-CDMA system. The key objective of the proposed algorithm is to utilize the reliability of the first stage of cell searching algorithm in order to accomplish the second stage. So the proposed algorithm makes the mobile station transfers to the second stage from the first stage, just after the slot synchronization is declared successively at the same time-offset. In order to compare the proposed algorithm with the conventional one, the simulations are accomplished for cell search algorithm for 3GPP W-CDMA systems in the multipath Rayleigh fading channel. Some parameters are also presented for the better performance in the initial cell searching algorithm.