• International Journal of Contents
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• 제5권3호
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• pp.8-13
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• 2009

The recent Web service field emerges as the fastest growing IT paradigm as a result of the increasing interest in SOA (Services-Oriented Architecture) and the expansion of B2B market. With an increasing number of Web service that provide similar features, it becomes more important to provide the most appropriate service for the user's request. A service user in general requires the quality information of Web service when selecting a service among a number of similar Web services. Yet, finding a service through UDDI (Universal Description, Discovery and Integration) does not consider the non-functional aspects of users because it is only based on the functional aspects. That is, the quality, non-functional aspect will be an important factor for the mutual success of the user and provider. Using 3 factors in the Qos factors of the existing studies: the execution cost, reliability, and the quality level, the QoS of Web service is saved and the factors for the QoS are recorded in order to consider non-functional factors when selecting a Web service in this study. The Quality Broker determines the rank and shows the desired result of the service for users. The Quality Broker suggested in this thesis can be used to select a Web Service that considers the user-oriented and non-functional factors.

• 한국멀티미디어학회논문지
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• 제13권9호
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• pp.1285-1298
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• 2010

비선점형 태스크 스케줄링 정책을 사용하는 TinyOS는 선입선출 (FIFO: First-In First-Out) 방식의 태스크 스케줄링만 제공하기 때문에 최상위 우선순위를 가친 사용자 태스크가 즉시 실행이 필요한 태스크임에도 불구하고 우선순위가 낮은 태스크가 획득한 CPU 사용권한을 선점하지 못한다. 따라서 실시간 서비스를 요구하는 사용자 태스크 (User Task) 의 마감시한 (Deadline)을 보장할 수 없다. 또한, 비선점 환경의 TinyOS에서 사용자 태스크가 요청한 실시간 서비스를 완료하기 위해서는 사용자 태스크의 마감시한을 보장함과 동시에 사용자 태스크에서 호출 및 실행되는 TinyOS 플랫폼 태스크들의 마감시한도 보장해야 한다. 이에 본 논문에서는 비선점형 태스크 스케줄링 정책을 사용하는 기존 TinyOS 환경에서 실시간성을 제공하는 태스크 그룹 기반의 스케줄링 기법을 제안하였다. 제안한 기법은 요청한 사용자 태스크의 마감시한을 보장하기 위하여 사용자 태스크와 함께 사용자 태스크가 완료되기 위하여 호출 및 실행이 필요한 다수의 TinyOS 플랫폼 태스크를 태스크 그룹으로 형성한 후, 해당 태스크 그룹을 하나의 가상적인 큰 태스크 단위로 스케줄링한다. 제안한 기법의 동작을 시험한 결과, 제안한 기법은 비선점형 태스크 스케줄링 정책을 사용하는 TinyOS 환경에서 사용자 태스크의 마감시한을 보장함과 동시에 사용자 태스크의 평균 응답시간을 줄이고 기존 TinyOS 플랫폼간의 호환성을 제공할 수 있었다.

• 경영과학
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• 제25권1호
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• pp.1-9
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• 2008

This paper investigates the R&D project portfolio selection problem. Despite its importance and impact on real world projects, there exist few practical techniques that help construct an non-dominated portfolio for a decision makers satisfaction. One of the difficulties constructing the portfolio is that such project portfolio problem is, in nature, a multi-attribute decision-making problem, which is an NP-hard class problem. This paper investigates the R&D project portfolio selection problem. Despite its importance and impact on real world projects, there exist few practical techniques that help construct an non-dominated portfolio for a decision makers satisfaction. One of the difficulties constructing the portfolio is that such project portfolio problem is, in nature, a multi-attribute decision-making problem, which is an NP-hard class problem. In order to obtain the non-dominated portfolio that a decision maker or a user is satisfied with, we devise a user-interface algorithm, in that the user provides the maximum/minimum input values for each project attribute. Then the system searches the non-dominated portfolio that satisfies all the given constraints if such a portfolio exists. The process that the user adjusts the maximum/minimum values on the basis of the portfolio found continues repeatedly until the user is optimally satisfied with. We illustrate the algorithm proposed, and the computational results show the efficacy of our procedure.

• 전기전자학회논문지
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• 제23권1호
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• pp.302-305
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• 2019

Non-orthogonal multiple access (NOMA) has been considered for the fifth generation (5G) mobile networks to provide high system capacity and low latency. We calculate the channel capacity for the weak channel user in NOMA and the channel capacity region for NOMA. In this paper, Gaussian mixture channel is compared to the additive white Gaussian noise (AWGN) channel. Gaussian mixture channel is modeled when we assume the practical signal modulation for the inter user interference, such as the binary phase shift keying (BPSK) modulation. It is shown that the channel capacity with BPSK inter user interference is better than that with Gaussian inter user interference. We also show that the channel capacity region with BPSK inter user interference is larger than that with Gaussian inter user interference. As a result, NOMA could perform better in the practical environments.

• Journal of Information Science Theory and Practice
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• 제6권3호
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• pp.25-36
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• 2018

Anonymity plays an increasingly important role on social media. This is reflected by more and more applications enabling anonymous interactions. However, do social media users behave different when they are anonymous? In our research, we investigated social media services meant for solely anonymous use (Jodel) and for widely spread non-anonymous sharing of pictures and videos (Instagram). This study examines the impact of anonymity on the behavior of users on Jodel compared to their non-anonymous use of Instagram as well as the differences between the user types: producer, consumer, and participant. Our approach is based on the uses and gratifications theory (U>) by E. Katz, specifically on the sought gratifications (motivations) of self-presentation, information, socialization, and entertainment. Since Jodel is mostly used in Germany, we developed an online survey in German. The questions addressed the three different user types and were subdivided according to the four motivation categories of the U>. In total 664 test persons completed the questionnaire. The results show that anonymity indeed influences users' usage behavior depending on user types and different U> categories.

• 한국통신학회논문지
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• 제37권1B호
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• pp.50-58
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• 2012

본 연구의 주된 목적은 사용자 관점에서 본 통신 시스템 서비스 가용도의 이론적 모델 개발이다. 이를 위하여 호(Call) 도착은 non-homogeneous 포아손 과정의 가정, 그리고 시스템 상태는 CTMC 모델의 가정을 토대로 서비스 가용도의 추계적 모델을 개발하였다. 제시한 모델은 시간에 따라 변하는 호 도착률을 포함하여 사용자 관점에서 본 서비스 신뢰도 모형의 사용자 모델을 효율적으로 나타냈다. 아울러 시스템 자원의 고장 없이도 사용자가 서비스를 받지 못하는 시스템 상태인 운영 고장 상태를 모델에 포함하여 제공자 입장이 아니라 사용자 관점에서 모델을 구축하였다.

• 정보처리학회논문지B
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• 제13B권6호
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• pp.625-632
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• 2006

협력적 여과는 사용자 선호도를 예측하기 위해 그 사용자의 유형을 학습하는 데 목적을 둔 기술이다. 협력적 여과 시스템이 전자상거래에서 성공적인 기술일지라도 그들은 데이터의 고차원성과 희박성이라는 문제점을 갖는다. 본 논문에서는 이와 같은 문제점을 해결하기 위하여 비부정 행렬 인수분해(NNMF, Non-negative Matrix Factorization) 방법을 이용한 최근 인접 협력적 여과 방법을 제안한다. 행렬을 분해하기 위한 전처리로서 사용자 변동 계수를 이용하여 사용자-아이템 행렬의 결측치를 채우고, 이를 대상으로 비부정 분해 방식을 적용하여 행렬을 인수분해 한다. 비부정 분해 방식을 적용한 긍정 분해는 사용자들을 의미를 갖는 벡터로써 표현함으로써 사용자들을 의미 관계를 갖는 그룹으로 표현한다. 이와 같이 벡터로 표현된 사용자들은 벡터 유사도에 의해 그들간의 유사도를 계산한다. 계산된 유사도의 정도에 의해 이웃을 결정하고, 이웃들이 평가한 아이템에 대한 흥미도를 기반으로 새로운 사용자가 평가하지 않은 아이템에 대한 결측치를 예측한다.

• 한국멀티미디어학회논문지
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• 제19권2호
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• pp.512-519
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• 2016

In this paper, we compared the user experience according to utilize parallax scrolling technique in web site. For this purpose, we divided subjects into two groups. The subjects of Group1 were given to use web site interface with Parallax scrolling and the Group2 were given to use web site interface with non Parallax scrolling. Then, All Subjects answered the questionnaire of user experience. User experience were evaluated by four entries as Novelty, Esthetics, Usage of Satisfaction, Cheerfulness. Consequently. As a result, the web site interface with Parallax scrolling showed significantly higher score of Novelty, Esthetics, Cheerfulness than the web site interface with non-Parallax scrolling. In this study. we proved that using the parallax scrolling technique in web site interface improves the overall user experience, and suggested to apply as a way to advance the attention and persistency on creating a web site.

• 한국문헌정보학회지
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• 제23권
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• pp.107-125
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• 1992

The purpose of this study is to investigate the research trend of information user studies. The following findings are made. The literature on information user studies during 1980-1990 reveals 120 titles. The faculty members of university tend to publish their results in scientific journals and university publication while non-faculty members are more likely to represent their research papers in unpublished master thesis and bulletin. Subject distribution of research were classified into ten: user studies, material use studies, information needs and uses, user education, library use pattern, citation analysis, journal use, catalog use, information system, non-use study. Survey research, literature research, survey reserch and literature research use jointly, experimental research and citation analysis were employed for information user studies.

• 대한지역사회영양학회지
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• 제9권3호
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• pp.303-314
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• 2004

We studied daily micronutrient intake from vitamin-mineral supplements, health-related life style, clinical case of diseases and food frequency of the Korean middle-aged (40-59 yr, n = 404) to compare the characteristics of non-user (n = 270) and user (n = 134) of vitamin-mineral supplements. Rate of supplement use of the middle-aged was 33.2% and there was significant difference in education level (p = 0.0084) and family income (p = 0.0476) of user and nonuser. Smoking habit (p = 0.0844) and drinking frequency (p = 0.0606) tended to be lower in a supplement user than a non-user. The medical history of a case was significantly higher in users (67.9%) than in non-users (44.4%) (p = 0.001), which suggests that medical history is one of the important motivations of supplement use. Supplement users had the medical history of digestive disease (34.1%), anemia (11.0%) and hypertension (9.9%) in order. Vitamin C was the most frequently supplemented nutrient (81.3%) among vitamin-mineral supplement, and the next orders were vitamins E (73.1%), B$_2$(68.7%) and B$_{6}$ (60.4%). Mean intakes of vitamin B$_1$, iron, selenium, vitamin E, and vitamin C from supplement was 4,260%, 4,030%, 1,660% and 1,330% of RDA, respectively. The supplement users tended to consume most food items including milk ＆ milk products (p ＜ 0.01), rice (p ＜ 0.01), grains (p ＜ 0.05) and cookies (p ＜ 0.01) less frequently than non-users. Conclusively, nutrient intake of vitamin B$_1$, iron, selenium, vitamin E, and vitamin C from supplement was excessively high compared to RDA. We suggest that the toxic effect of excessive supplementation should he informed to supplement user and nutritional education should be focused on the optimal supplement dose.e.