• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2012년도 추계학술발표대회
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• pp.396-399
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• 2012

Topic detection is a problem of discovering the topics of online publishing documents. For topic detection, it is important to extract correct topic words and to show the topical words easily to understand. We consider a topic tree-based approach to more effectively and more briefly show the result of topic detection for online text documents. In this paper, to achieve the topic tree-based topic detection, we propose a new term weighting method, called CTF-CDF-IDF, which is simple yet effective. Moreover, we have modified a conventional clustering method, which we call incremental k-medoids algorithm. Our experimental results with Reuters-21578 and Google news collections show that the proposed method is very useful for topic detection.

• 정보관리학회지
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• 제22권1호
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• pp.191-208
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• 2005

새로운 주제의 탐지를 위한 여러 접근법들을 지식 구조 표현 방법 중 하나인 디스크립터의 부여 및 갱신 과정에 적용하였다. 새로운 주제 탐지는, 특히 특정 학문 분야에서 새로운 주제의 출현 및 성장으로 인하여 지식구조상의 변화가 발생하는 경우에, 기존의 색인어로는 이를 표현할 수 없거나 표현상의 제한이 따르는 문제를 해결하는 데 응용할 수 있다. 실험 결과, 정보학 내에서 긍정적 측면의 변화가 발생한 것으로 식별된 신흥 주제들은 상당수가 서로 밀접하게 연관되어 있으면서 동시에 성장${\cdot}$발전의 단계에 있는 주제임을 확인하였다. 또한, 새로운 주제 탐지를 통한 후보 디스크립터 리스트의 사용이 색인자의 색인작업을 지원하는 효율적인 도구가 될 수 있다는 가능성을 보여 주었다. 특히, 적절한 디스크립터의 선정과 부여를 위한 후보 디스크립터 리스트의 제공은 색인작업의 효율성과 정확성을 향상시키는 데 기여할 수 있을 것이다.

• International Journal of Computer Science & Network Security
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• 제21권12spc호
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• pp.415-426
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• 2021

The implementation of iris biometrics on smartphone devices has recently become an emerging research topic. As the use of iris biometrics on smartphone devices becomes more widely adopted, it is to be expected that there will be similar efforts in the research community to beat the biometric by exploring new spoofing methods and this will drive a corresponding requirement for new liveness detection methods. In this paper we addresses the problem of presentation attacks (Spoofing) against the Iris Recognition System on mobile devices and propose novel Presentation Attack Detection (PAD) method which suitable for mobile environment.

• 한국컴퓨터정보학회논문지
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• 제23권1호
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• pp.17-24
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• 2018

With improvement of speech recognition and natural language processing, dialog systems are recently adapted to various service domains. It became possible to get desirable services by conversation through the dialog system, but it is still necessary to improve separate modules, such as domain detection, intention detection, named entity recognition, and out-of-domain detection, in order to achieve stable service offer. When it misclassifies an in-domain sentence of conversation as out-of-domain, it will result in poor customer satisfaction and finally lost business. As there have been relatively small number of studies related to the out-of-domain detection, in this paper, we introduce a new method using a hierarchical Dirichlet process and demonstrate the effectiveness of it by experimental results on Korean dataset.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권11호
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• pp.5592-5609
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• 2017

JPEG steganography detection is an active research topic in the field of information hiding due to the wide use of JPEG image in social network, image-sharing websites, and Internet communication, etc. In this paper, a new steganalysis method for content-adaptive JPEG steganography is proposed by integrating the evolutionary feature selection and classifier ensemble selection. First, the whole framework of the proposed steganalysis method is presented and then the characteristic of the proposed method is analyzed. Second, the feature selection method based on genetic algorithm is given and the implement process is described in detail. Third, the method of classifier ensemble selection is proposed based on Pareto evolutionary optimization. The experimental results indicate the proposed steganalysis method can achieve a competitive detection performance by compared with the state-of-the-art steganalysis methods when used for the detection of the latest content-adaptive JPEG steganography algorithms.

• 한국정보시스템학회지:정보시스템연구
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• 제30권4호
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• pp.277-301
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• 2021

Purpose The purpose of this study is to analyze the sentiment responses of the general public to non-face-to-face work using text mining methodology. As the number of non-face-to-face complaints is increasing over time, it is difficult to review and analyze in traditional methods such as surveys, and there is a limit to reflect real-time issues. Approach This study has proposed a method of the research model, first by collecting and cleansing the data related to non-face-to-face work among tweets posted on Twitter. Second, topics and keywords are extracted from tweets using LDA(Latent Dirichlet Allocation), a topic modeling technique, and changes for each section are analyzed through DTM(Dynamic Topic Modeling). Third, the complaints of non-face-to-face work are analyzed through the classification of positive and negative polarity in the COVID-19 section. Findings As a result of analyzing 1.54 million tweets related to non-face-to-face work, the number of IDs using non-face-to-face work-related words increased 7.2 times and the number of tweets increased 4.8 times after COVID-19. The top frequently used words related to non-face-to-face work appeared in the order of remote jobs, cybersecurity, technical jobs, productivity, and software. The words that have increased after the COVID-19 were concerned about lockdown and dismissal, and business transformation and also mentioned as to secure business continuity and virtual workplace. New Normal was newly mentioned as a new standard. Negative opinions found to be increased in the early stages of COVID-19 from 34% to 43%, and then stabilized again to 36% through non-face-to-face work sentiment analysis. The complaints were, policies such as strengthening cybersecurity, activating communication to improve work productivity, and diversifying work spaces.

• 한국위성정보통신학회논문지
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• 제12권1호
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• pp.28-33
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• 2017

본 논문에서는 여러 곳에서 통용되고 있는 기존의 CW(continuous-wave) 레이더 송수신모델을 수정한 송수신모델을 제안한다. 최근에 심장박동과 호흡을 검출하기 위해 기존신호모델을 기반으로 CW(continuous-wave) 레이더에 대한연구가 진행 되고 있다. 그러나 이 통용되고 있는 수신모델은 인체 공학적으로 개념과 일치하지 않기 때문에 이모델을 근거로 실험을 할 경우 실제 개발되는 시스템 성능을 정확하게 예측할수 없다. 본 논문에서는 인체 공학상 개념과 일치하는 수정된 CW(continuous-wave) 레이더 송수신모델을 제안하고 가운시안 잡음rhk 다중경로 환경에서 심장박동 및 호흡검출에 대한 시뮬레이션을 수행하고 이를 기존수신모델과의 심장박동과 호흡검출에 대한 성능을 비교 분석한다.

• 정보과학회 논문지
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• 제42권12호
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• pp.1522-1534
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• 2015

본 연구에서는 미리 구축해 놓은 학습데이터 없이도 입력된 작문이 주어진 작문 주제에 적합한 내용인지 아닌지를 자동으로 판단할 수 있는 방법을 제안한다. ConceptNet은 다양한 종류의 문서에서 추출한 자연언어 문장들로부터 구축된 그래프 형태의 지식베이스이다. 본 연구에서는 작문 주제에 해당하는 작문 프롬프트(essay prompt)와 ConceptNet만을 이용하여 문서의 주제-이탈 여부를 판별하는 방법을 제안한다. ConceptNet에서 두 개념간의 최단 경로를 찾고 이에 대한 의미 유사도를 계산하는 방법을 제안한다. 이를 이용하여 작문 프롬프트와 수험생 작문 내용을 ConceptNet의 개념들로 매핑하고 이 개념들 사이의 의미 유사도를 계산하여 작문 프롬프트와 수험생 작문 사이의 주제 부합 여부를 판단한다. 8개의 작문 시험을 수행하여 얻은 수험생 작문 데이터에 대하여 평가를 수행한 결과 기존의 연구에 비해 좋은 성능을 얻을 수 있었다. ConceptNet을 활용하면 유의미한 단순 추론이 가능하기 때문에 본 연구에서 제안한 방법은 추론을 요하는 작문 문제에도 적용 가능함을 보였다.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2008년도 제38차 하계학술발표논문집 16권1호
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• pp.199-204
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• 2008

Visual surveillance is an active topic recently in Computer Vision. Event detection and recognition is one important and useful application of visual surveillance system. In this paper, we propose a new method to recognize the entering and exiting events based on the human's movement feature and the door's state. Without sensors, the proposed approach is based on novel and simple vision method as a combination of edge detection, motion history image and geometrical characteristic of the human shape. The proposed method includes several applications such as access control in visual surveillance and computer vision fields.

• 한국멀티미디어학회논문지
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• 제11권6호
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• pp.787-795
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• 2008

Human recognition on camera is an interesting topic in computer vision. While fingerprint and face recognition have been become common, gait is considered as a new biometric feature for distance recognition. In this paper, we propose a gait recognition algorithm based on the knee angle, 2 feet distance, walking velocity and head direction of a person who appear in camera view on one gait cycle. The background subtraction method firstly use for binary moving object extraction and then base on it we continue detect the leg region, head region and get gait features (leg angle, leg swing amplitude). Another feature, walking speed, also can be detected after a gait cycle finished. And then, we compute the errors between calculated features and stored features for recognition. This method gives good results when we performed testing using indoor and outdoor landscape in both lateral, oblique view.