• 제목/요약/키워드: comment

검색결과 399건 처리시간 0.026초

A reversible data hiding scheme in JPEG bitstreams using DCT coefficients truncation

  • Zhang, Mingming;Zhou, Quan;Hu, Yanlang
    • KSII Transactions on Internet and Information Systems (TIIS)
    • /
    • 제14권1호
    • /
    • pp.404-421
    • /
    • 2020
  • A reversible data hiding scheme in JPEG compressed bitstreams is proposed, which could avoid decoding failure and file expansion by means of removing of bitstreams corresponding to high frequency coefficients and embedding of secret data in file header as comment part. We decode original JPEG images to quantified 8×8 DCT blocks, and search for a high frequency as an optimal termination point, beyond which the coefficients are set to zero. These blocks are separated into two parts so that termination point in the latter part is slightly smaller to make the whole blocks available in substitution. Then spare space is reserved to insert secret data after comment marker so that data extraction is independent of recovery in receiver. Marked images can be displayed normally such that it is difficult to distinguish deviation by human eyes. Termination point is adaptive for variation in secret size. A secret size below 500 bits produces a negligible distortion and a PSNR of approximately 50 dB, while PSNR is also mostly larger than 30 dB for a secret size up to 25000 bits. The experimental results show that the proposed technique exhibits significant advantages in computational complexity and preservation of file size for small hiding capacity, compared to previous methods.

댓글이 음원 판매량에 미치는 차별적 영향에 관한 텍스트마이닝 분석 (The Impact of Comments on Music Download and Streaming: A Text Mining Analysis)

  • 박명석;권영진;이상용
    • 지식경영연구
    • /
    • 제19권2호
    • /
    • pp.91-108
    • /
    • 2018
  • This study mainly focused on measuring the impact of comments for a particular song on the number of streamings and downloads. We modeled multiple regression equations to perform this analysis. We chose digital music market for the object of analysis because of its inherent characteristics, such as experience goods, high bandwagon effect, and so on. We carefully utilized text mining technique in accordance with the algorithm of Naïve Bayes classifier to distinguish whether a comment for a piece of music be regarded as positive or negative. In addition, we used 'size of agency' and 'existence of hit song' as moderating variables. The reason for usage of those variables is that those are assumed to affect users' decision for selecting particular song especially when downloading or streaming via music sites. We found empirical evidences that positive comments for a particular song increase the number of both downloads and streamings. However, positive comments may decrease the number of downloads when the size of agency of the artist is big. As a result, we were able to say that a positive comment for a particular song functioned as 'word-of-mouth' effect, inducing other users' behavioral response. We also found that other features of an artist such as size of the agency that the artist belongs to functioned as an external factor along with feature of the song itself.

The Main Contents, Comment and Future Task for the Space Laws in Korea

  • Kim, Doo-Hwan
    • 한국항공우주법학회:학술대회논문집
    • /
    • 한국항공우주법학회 2008년도 제40회 국제학술발표대회
    • /
    • pp.273-294
    • /
    • 2008
  • Korea now has a rapidly expanding space programme with exploration aspirations. The government is giving priority to the aerospace industry and, to put it on a better footing, enacted an Aerospace Industry Development Promotion Act in 1987, a Space Development Promotion Act in 2005 and a New Space Compensation for Damage Act in 2007. I would like to describe briefly the legislative history, main contents and comment for these three space acts including especially launch licensing, registration of space objects, use of satellite information, astronaut rescue, liability for compensation, third party liability insurance and establishment of committee and plans to assist the Korean space effort. Furthermore author proposed to legislate a draft for the establishment of a new Korean National Space Development Agency (KNSDA: tentative title) to create a similar body to Japan Aerospace Exploration Agency (JAXA), British National Space Centre (BNSC) of UK, French Centre National d'Etudes Spatiales (CNES), German Aerospace Center (DLR), Swedish Space Corporation, China Aerospace Science and Industry Corporation, Indian Space Research Organization (ISRO) as well as the Korean Space Agency (KSA: Tentative title) to create a similar body to Canadian Space Agency, European Space Agency, Russian Space Agency, Italian Space Agency, Israel Space Agency, Indian Department of Space, National Aeronautics and Space Administration (NASA) of USA, China National Space Administration in order to develope efficiently space industry. A call is made for Asian countries to unite and further their space development through a regional space agency.

  • PDF

온라인 커뮤니티 성장에 영향을 미치는 요인에 관한 연구 (An Study on Determinants Affecting a Growth of Online Community)

  • 곽나연
    • 디지털산업정보학회논문지
    • /
    • 제12권4호
    • /
    • pp.163-169
    • /
    • 2016
  • This study is to analyze factors affecting a growth of online community with perspectives of social network. Particularly this study tries to explore structural phenomenon built by interactions between users in a certain of free board belonging to the online community, in which focuses on one's writing a comments responding on those of others. With using SNA(Social Network Analysis), the social network data calculated from users' interaction shown as their comments were collected to draw out each individual's centrality value representing the structure of the online community and also we estimated duration time and the number of each comments as a proxy variable representing growth of the online community. And then cause-and-effect relationship between individual's centrality value and the duration time and the number of each comment were analyzed. As a result of the analysis, Core-Periphery, Centralization and Reciprocity have significant effects on the duration time and the number of each comment, therefore those significant values representing online structure will give an implication to manage, to promote the online community, to forecast its evolution path and to build critical policies.

초등수학과 수행평가도구 개발 -1, 2학년 포트폴리오를 중심으로- (A Study on Development of Performance Assessment Tools for Mathematics in the Primary School)

  • 정영옥
    • 대한수학교육학회지:학교수학
    • /
    • 제2권2호
    • /
    • pp.357-388
    • /
    • 2000
  • This study aims to develop performance assessment tools for mathematics in the primary school. In order to achieve this aim, it reviews the tics in the primary school. In order to achieve this aim, it reviews the meaning and the purpose of mathematics performance assessment, and the characteristics of performance assessment tasks. Then the framework for portfolio developed in this study is introduced. This portfolio is called 'mathematical thinking and applying'. It aims at balanced assessment for improvement of mathematics instruction. It is composed of journal writhing, problem by the student, constructed task, work samples, written test, self assessment, teacher's comment and parents' comment. The criteria of performance tasks is categorized in impact, reasoning, accuracy and communication. The procedures of development of these tasks are as follows: the analysis of mathematics curriculum for the primary school, the design of performance tasks with considering teaching unit goals, designing rubrics, discussing these tasks with teachers in primary school, modifying them when is needed, observing the process of children's task performing, interviewing with teachers and final modifying. After performance assessment tasks are implemented, the answers by the students is analyzed using rubrics. Then anchor papers are selected. Also, the errors of children are analyzed. Through the process, teachers can obtain the information of children for improvement of mathematics instruction. Finally in order to generalize this study, I suggest that we need to cooperate with the field of education and to establish expert assessment groups.

  • PDF

영양상담을 위한 전산화 프로그램 개발연구 (Development of computer programs for Nutrition Counseling)

  • 홍순명
    • Journal of Nutrition and Health
    • /
    • 제22권4호
    • /
    • pp.275-289
    • /
    • 1989
  • The purpose of this study is to develop a computer system with data file and computerized programs for nutrition counseling. In this research, a 16 / XT personal computer (word : COBOL) compatible with IBM-PC/XT was used. Computer system developed for this study was as follows: Data files(food composition list, food exchange list, nutrition management comment, special diet therapy) were used for analysis the nutritional status and the ntrition education comment. (1) Programs for the nutritional status assessment 1) General information a) Name, age, sex, higher, weight, activity, disease and special diet b) Ideal body weight and Obesity assessment(Kaup index and Broca index) c) Rest and athletics status d) Biochemical data comparision with standard 2) Food Intakes 3) Nutrient Intakes a) Comparison of the amounts intaked with the recommended dietary allowances for present weight. b) Comparison of the energy composition rate intaked with the recommended dietary allowances for present weight. b) Comparison of the energy composition rate intaked with the recommended for present weight and ideal weight. c) Nutrient analysis by each meal and snack. 4) Food intakes from each food group and comparison with recommended 5) Special nutrient analysis. (2) Programs for the nutrition education based on nutritional status assessment. 1) Suggestion of number of food exchange group 2) Nutritional assessment and advise comments 3) Nutritional management comments 4) Special diet therapy In the study, the nutritioal status and nutrition education comments are based on individual data from nutrition counseling.

  • PDF