• Journal of the Korea Society of Computer and Information
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• v.19 no.5
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• pp.79-87
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• 2014

In this paper, we propose contents sharing model for consolidating distributed collaboration environments. We provide the combined model by integrating different features-scalable resolution display walls resource, sharing contents on local and remote, multi-user interaction, and access control. There is a benefit that every user can interact within an environment, but overlaps would occur because of multi-user interaction. To manage overlap issue, the model includes access control. Access control would interfere flow of work process. Therefore, we conduct user study to evaluate these two factors of the model. The result shows that the proposed contents sharing model makes it possible to concentrate in a work.

• Proceedings of the ESK Conference
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• 1995.10a
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• pp.41-45
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• 1995

Menu-driven interfaces are frequently employed for user -system interfaces on many electronic products. Due to the space and budget constraint, a single or multi-line display is used to show menu items. Single or Multi-line display present 8 .approx. 21 characters on an LCD screen and users select items using a series of button pushes. Multi-line displays are different from the single-line ones in the following aspects. First, they can present multiple menu items at the same time. Second, they can present menu items in a various way, for example, same-depth presentation, sub-depth presentation, previous selection, etc. In this study, a human factors experiment is being conducted to examine the effects of three independent variables on the design of a multi-line display. Factors investigated include menu structure, number of lines on the display, item presentation methodl. Usability of the multi-line display is being measured quantitatively in terms of four different aspects: task completion time, accuracy, inefficiency, user preference. A set of design guidelines will be drawn from this study which can be applied to usef-system interfaces of a various types of consumer products.

• Journal of KIISE:Software and Applications
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• v.30 no.5_6
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• pp.540-549
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• 2003

In collaborative recommendation two models are generally used: the user model and the article model. A user model learns correlation between users preferences and recommends an article based on other users preferences for the article. Similarly, an article model learns correlation between preferences for articles and recommends an article based on the target user's preference for other articles. In this paper, we investigates various combination methods of the user model and the article model for better recommendation performance. They include simple sequential and parallel methods, perceptron, multi-layer perceptron, fuzzy rules, and BKS. We adopt the multi-layer perceptron for training each of the user and article models. The multi-layer perceptron has several advantages over other methods such as the nearest neighbor method and the association rule method. It can learn weights between correlated items and it can handle easily both of symbolic and numeric data. The combined models outperform any of the basic models and our experiments show that the multi-layer perceptron is the most efficient combination method among them.

• The KIPS Transactions:PartC
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• v.12C no.7 s.103
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• pp.999-1006
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• 2005

The Secure OS is an operating system which adds security functions to the existing operating system, in order to secure a system from sorority problems originated from inherent frailty of applications or operating systems. With the existing Secure Oses for it is difficult to set an effective security policy securing personal resources in a multi-user environment system. To solve this problem in this paper we present two Techniques to secure user data efficiently in the RBAC-based Secure OS for a multi-user environment. Firstly we utilizes object's owner information in addition to object's filename. Secondly we make use of meta symbol('$\ast$'), which is able to describe multiple access targets. In addition this paper gives some examples to show advantages from these techniques. And these features are implemented in an solaris-based Secure OS called Secusys.

• The Journal of the Korea Contents Association
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• v.10 no.3
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• pp.141-148
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• 2010

The aim of this paper is to propose a communication middleware which makes it possible to easily and efficiently develop the networking support for multi-user applications. Even though existing middleware and development tools provides lots of functionalities to realize distributed applications, they are purely low-level services passing the most development efforts to developers, or too specialized for a specific application. It brings a challenging issue of how the middleware supports general and efficient high-level mechanisms. To meet different networking and interaction requirements of multi-user applications, we propose various schemes to provide the communication architecture, the user membership management, the content transmission mechanism and the event management. Our middleware provides developers with application-level APIs and configuration files so that the different interaction requirements of a multi-user application can be easily handled in the developers' point of view.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.4C
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• pp.386-394
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• 2010

In this paper, we propose an adaptive coordinated Tx-Rx beamforming scheme for inter-user interference cancellation, when a BS communicates with multiple users that each has multiple receive antenna. The conventional coordinated Tx-Rx beamforming scheme uses a fixed multi-stream per user regardless of the instantaneous channel states, that is, both user with ill-conditioned and well-conditioned channels have the same number of data streams. However, in the proposed adaptive coordinated Tx-Rx beamforming scheme, we select the number of streams per user to solve the inefficient problem of the conventional coordinated Tx-Rx beamforming. As a result of applying the adaptive coordinated Tx-Rx beamforming scheme, the BER performance is improved. Simulation results show that the proposed algorithm outperforms the conventional coordinated Tx-Rx beamforming algorithm by 2.5dB at a target BER of $10^{-2}$.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.3
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• pp.372-377
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• 2006

In this paper, we propose sensibility recognition model that recognize user's sensibility using brain waves. Method to acquire quantitative data of brain waves including priority living body data or sensitivity data to recognize user's sensitivity need and pattern recognition techniques to examine closely present user's sensitivity state through next acquired brain waves becomes problem that is important. In this paper, we used pattern recognition techniques to use Multi Layer Perceptron (MLP) that is pattern recognition techniques that recognize user's sensibility state through brain waves. We measures several subject's emotion brain waves in specification space for an experiment of sensibility recognition model's which propose in this paper and we made a emotion DB by the meaning data that made of concentration or stability by the brain waves measured. The model recognizes new user's sensibility by the user's brain waves after study by sensibility recognition model which propose in this paper to emotion DB. Finally, we estimates the performance of sensibility recognition model which used brain waves as that measure the change of recognition rate by the number of subjects and a number of hidden nodes.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.1
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• pp.3-14
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• 2011

In recent days, people used to store and share the data with other users through the web storage services. It is more convenient for using the data, but it raise problems such as access control of stored data and privacy exposure to untrusted server. Searchable encryption is used to share the data securely in multi-user setting. Especially in the multi-user setting, the revoked users should not be able to search the data and access the stored data. That is, it should be considered the security from revoked users. However in the existing schemes, the revoked users can decrypt the shared data by passive attack. Proposed scheme is the secure searchable encryption that resolves the problem and guarantees the security for revoked users.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.2
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• pp.811-829
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• 2015

One-way authenticated key agreement protocols, aiming at solving the problems to establish secure communications over public insecure networks, can achieve one-way authentication of communicating entities for giving a specific user strong anonymity and confidentiality of transmitted data. Public Key Infrastructure can design one-way authenticated key agreement protocols, but it will consume a large amount of computation. Because one-way authenticated key agreement protocols mainly concern on authentication and key agreement, we adopt multi-server architecture to realize these goals. About multi-server architecture, which allow the user to register at the registration center (RC) once and can access all the permitted services provided by the eligible servers. The combination of above-mentioned ideas can lead to a high-practical scheme in the universal client/server architecture. Based on these motivations, the paper firstly proposed a new one-way authenticated key agreement scheme based on multi-server architecture. Compared with the related literatures recently, our proposed scheme can not only own high efficiency and unique functionality, but is also robust to various attacks and achieves perfect forward secrecy. Finally, we give the security proof and the efficiency analysis of our proposed scheme.

• Journal of Korea Multimedia Society
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• v.10 no.6
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• pp.799-806
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• 2007

The prototypical smart environment to support the context-aware interactions between user and ubiquitous campus environment based on multi-agent system paradigm is proposed in this paper. In this model, the dynamic Bayesian is investigated to solicit and organize agents to produce information and presentation assembly process in order to allocate the resources for an unseen task across multiple services in a dynamic environment. The user model is used to manage varying user constraints and user preferences to achieve system's goals.