• Journal of KIISE:Software and Applications
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• v.31 no.8
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• pp.1062-1072
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• 2004

Collaborative filtering systems based on ｛user-document｝ matrix are effective in recommending web documents to user. But they have a shortcoming of decreasing the accuracy of recommendations by the first rater problem and the sparsity. This paper proposes the automatic preference rating method that generates user profile to solve the shortcoming. The profile in this paper is content-based collaborative user profile. The content-based collaborative user profile is generated by combining a content-based user profile with a collaborative user profile by mutual information method. Collaborative user profile is based on ｛user-document｝ matrix in collaborative filtering system, thus, content-based user profile is generated by relevance feedback in content-based filtering systems. After normalizing combined content-based collaborative user profiles, it automatically rates user preference by reflecting normalized profile in ｛user-document｝matrix of collaborative filtering systems. We evaluated our method on a large database of user ratings for web document and it was certified that was more efficient than existent methods.

• Journal of the Korean Association of Geographic Information Studies
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• v.1 no.1
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• pp.70-85
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• 1998

This study intends to identify the effects of user attitude, user education & training on the information systems implementation performance. In order to obtain data, survey questionnaires were distributed to the users of 'D' company, the major findings can be summarized as follows. First, it's suggested from the analyses that user attitude and user education & training independently have statistically significant effects on information systems implementation performance. Second, it's revealed that even though the interaction effects by both user attitude and user education & training have positive effects on the level of usage, but have no statistically significant effects on satisfaction level. Based on these results, it's recommended to convert user attitude favorably toward user environment and to increase the level of user education & training, in order to promote information systems implementation performance. Especially, differentiated user education & training are highly recommended.

• Archives of design research
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• v.20 no.2 s.70
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• pp.5-16
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• 2007

The main objective of our research is analyzing user's emotional changes while using a product, to reveal the influence of usability on human emotions. In this study we have extracted some emotional words that can come up during user interaction with a product and reveal emotional changes through three methods. Finally, we extracted 88 emotional words for measuring user's emotions expressed while using products. And we categorized the 88 words to form 6 groups by using factor analysis. The 6 categories that were extracted as a result of this study were found to be user's representative emotions expressed while using products. It is expected that emotional words and user's representative emotions extracted in this study will be used as subjective evaluation data that is required to measure user's emotional changes while using a product. Also, we proposed the effective methods for measuring user's emotion expressed while using a product in the environment which is natural and accessible for the field of design, by using the emotion mouse and the Eyegaze. An examinee performs several tasks with the emotion mouse through the mobile phone simulator on the computer monitor connected to the Eyegaze. While testing, the emotion mouse senses user's EDA and PPG and transmits the data to the computer. In addition, the Eyegaze can observe the change of pupil size. And a video camera records user's facial expression while testing. After each testing, a subjective evaluation on the emotional changes expressed by the user is performed by the user him/herself using the emotional words extracted from the above study. We aim to evaluate the satisfaction level of usability of the product and compare it with the actual experiment results. Through continuous studies based on these researches, we hope to supply a basic framework for the development of interface with consideration to the user's emotions.

• Journal of Digital Convergence
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• v.6 no.4
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• pp.177-183
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• 2008

This paper aims to offer a solution based on intelligent document classification to create a user-centric information retrieval system allowing user-centric linguistic expression. So, structures expressing user intention and fine document classifying process using EBL, similarity, knowledge base, user intention, are proposed. To overcome the problem requiring huge and exact semantic information, a hybrid process is designed integrating keyword, thesaurus, probability and user intention information. User intention tree hierarchy is build and a method of extracting group intention between key words and user intentions is proposed. These structures and processes are implemented in HDCI(Hybrid Document Classification with Intention) system. HDCI consists of analyzing user intention and classifying web documents stages. Classifying stage is composed of knowledge base process, similarity process and hybrid coordinating process. With the help of user intention related structures and hybrid coordinating process, HDCI can efficiently categorize web documents in according to user's complex linguistic expression with small priori information.

• Journal of Information Processing Systems
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• v.14 no.2
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• pp.523-538
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• 2018

Keystroke dynamics user authentication is a behavior-based authentication method which analyzes patterns in how a user enters passwords and PINs to authenticate the user. Even if a password or PIN is revealed to another user, it analyzes the input pattern to authenticate the user; hence, it can compensate for the drawbacks of knowledge-based (what you know) authentication. However, users' input patterns are not always fixed, and each user's touch method is different. Therefore, there are limitations to extracting the same features for all users to create a user's pattern and perform authentication. In this study, we perform experiments to examine the changes in user authentication performance when using feature vectors customized for each user versus using all features. User customized features show a mean improvement of over 6% in error equal rate, as compared to when all features are used.

• Journal of the Korea Society of Computer and Information
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• v.21 no.10
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• pp.63-68
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• 2016

Recently, Biometrics is being magnified than ID or password about user authentication. However, unlike a PIN, password, and personal information there is no way to modify the exposure if it is exposed and used illegally. As FIDO(Fast IDentity Online) than existing server storing method, It stores a user's biometric information to the user device. And the user device authentication using the user's biometric information, the user equipment has been used a method to notify only the authentication result to the server FIDO. However, FIDO has no mutual authentication between the user device and the FIDO server. We use a Certificate Authority in order to mutually authenticate the user and the FIDO server. Thereby, we propose a more reliable method and compared this paper with existed methods about security analysis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.9
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• pp.1590-1595
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• 2006

This paper proposes a technique of user oriented document ranking using user refile to provide more satisfied results which reflect preference of specific users. User profile is constructed to represent his or her preference. User pfofile consists of 'term array' and 'preference vector' according to the interest field of one. And the User profile for a particular person is updated by 'user access', 'latent relaeon', 'User Profile' proposed in this paper. The latent structures of documents in same domain are analysed by singular value decomposition(SVD). Then, the rank of documents is determined by comparison of user profile with analyzed document on the basis of relevance.

• International Journal of Contents
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• v.8 no.3
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• pp.79-82
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• 2012

In digital contents distribution environments, a user authentication is an important security primitive to allow only authenticated user to use right services by checking the validity of membership. For example, in Internet Protocol Television (IPTV) environments, it is required to provide an access control according to the policy of content provider. Remote user authentication and key agreement scheme is used to validate the contents accessibility of a user. We propose a novel user authentication scheme using smart cards providing a secure access to multimedia contents service. Each user is authenticated using a subset of attributes which are issued in the registration phase without revealing individual's identity. Our scheme provides the anonymous authentication and the various permissions according to the combination of attributes which are assigned to each user. In spite of more functionality, the result of performance analysis shows that the computation and communication cost is very low. Using this scheme, the security of contents distribution environments in the client-server model can be significantly improved.

• Journal of Korea Society of Digital Industry and Information Management
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• v.14 no.3
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• pp.77-85
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• 2018

Multi-User Multiple-Input Multiple-Output (MU-MIMO) is the core technology for improving the channel capacity compared to Single-User MIMO (SU-MIMO) by using multiuser gain and spatial diversity. Key problem for the MU-MIMO is the user selection which is the grouping the users optimally. To solve this problem, we adopt Extreme Value Theory (EVT) at the beginning of the proposed algorithm, which defines a primary user set instead of a single user that has maximum channel power according to a predetermined threshold. Each user in the primary set is then paired with all of the users in the system to define user groups. By comparing these user groups, the group that produces a maximum sum rate can be determined. Through computer simulations, we have found that the proposed method outperforms the conventional technique yielding a sum rate that is 0.81 bps/Hz higher when the transmit signal to noise ratio (SNR) is 30 dB and the total number of users is 100.

• Management & Information Systems Review
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• v.3
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• pp.399-417
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• 1999

The purpose of this paper id to study the factors influencing MIS user satisfaction. For this purpose. I have reviewed the results of past studies on the performance factor of MIS, and introduced a new model associated with small & Medium Business. On the basis of this model, I have hypothesized that the following variables influence user satisfaction : (gender, age), individual characteristics(user attitude, training for user), managerial characteristic(top management involvement, organizational support) and task characteristics(task structure). There were 195 participants surveyed using questionnaires from 25 different small & medium Business in Pusan. The research model and associated hypotheses were tested by following statistical techniques: reliability test, regression, t-test and ANOVA. The findings of this study are follows; 1. It was found that gender and age are not correlated user satisfaction. 2. Among individual characteristics, only user attitude influence user satisfaction significantly. 3. While organizational supports influence positively user satisfaction, top management involvement do not influence it. 4. Task structure is highly correlated with user satisfaction. In spite of many factors affecting MIS success, this study did not consider all variables affect on user satisfaction. We need integrated model including more various factors.