• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.4
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• pp.315-325
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• 2014

In ubiquitous environment, User's location information is very important to serve personalized service to user. Previous works consider only User's locations in the big buildings and assume APs are fixed. Normal home environment, However, is consists of small spaces. And the state of APs is highly fluid. Previous research has focused on indoor localization in the building where has stationary AP environment. However, in this paper, we propose as User's Location Predicting System that finds out a space where a user is located based on Wi-Fi Fingerprint approach in home environments. The results that conducted real home environments are using the system show more than 80% accuracy.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.5
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• pp.387-395
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• 2009

The establishment of security architecture is essential because security vulnerabilities occur such as user's unjustifiable connection for the opened gateway and access to resources without permission in OSGi service platform environment. In this paper, it proposes a authentication technique for an Automatic user authentication which is used the Symmetric Key and the Service bundle authentication to consider the constraints of the hardware in the OSGi service platform environment. Typically, the type of entering a password is used for the user authentication mechanism however OSGi platform environment studies not entering the password but using MAC address and encrypted identifier of the automatic user authentication mechanism because the devices are limited in their input. In this paper, the Symmetric Key is used for bundle authentication mechanism. Therefore operation becomes quick and secure authentication process has been successfully completed by using the time data and a ticket which contains a license. Based on these two different authentication mechanisms, it could eliminate the constraints of resources and improve the convenience of users and administrators. Also it shows an effect from omitting the waiting time to enter a password and reducing operations which need for authentication in the OSGi service platform environment.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.5
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• pp.209-218
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• 2005

In this paper, we propose CIVE, context-based interactive system for heterogeneous distributed virtual environments that delivers contexts irom real world to virtual environment and vice versa. The proposed system ronsists of obi-UCAM for generating user's contexts, NAVER for managing virtual environment, and Interface for linking obi-UCAM with NAVER. The connection between real and virtual worid through context is brneficial in following ways. Firstly. CIVE Provides a personalized user interface for virtual environment according to a user profile such as identity, age and vernacular. Secondly, translating all input signals into context, it guarantees adaptive access that enables a user to exploit unencumbered input devices controlling a shared object in virtual environment even if he moves with his own device from a virtual system to another. Finally, it provides a mechanism for synchronizing distributed virtual systems that share context representing changes at remote nodes. The context reduces the inconsistency of representing the same data among heterogeneous systems. Therefore, CIVE plays an important role in implementing VR applications such as teleconference, game and entertainment.

• Journal of the Korea Society for Simulation
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• v.20 no.1
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• pp.39-49
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• 2011

Nowaday, Many equipments like TabletPC, Digital kiosk, ATM using touch-panel service instead of keyboard or button, to support intuitively input for user. Furthermore these days touch-panels recognize up to 5 contact points using recent technology. On this study, I Introduce password input/store methodology on multi-touch environment. On past, User must input password 1 character by 1 character, like [1, 2, 3, 4]. but, on multi-touch environment user can input more than one character at the same time, like [(1,3), 2, (3,4), (1,2,3)]. In result, users can use password more intensely. This study is utilized post security technology study on multi-touch environment.

• Journal of Korea Multimedia Society
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• v.16 no.7
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• pp.879-887
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• 2013

In the recently diversified web environment, the existing methodologies for studying and evaluating the usability of infographics have limit in being applied to new user experience environment. To ensure effective web design that considers various user environments, research needs to be done for such usability of infographics that executes 'simplification and compression of information'. The purpose of this study is to understand the expandability of web-based infographic design, re-establish its concept, and produce the elements involved in the usability evaluation to come up with effective data on user experience. It is expected that this study will be used as a basic research for elucidating the connection to type-based or experienced-based data through convergence of various areas of information technology in the continuously transforming smart media environment.

• Asia pacific journal of information systems
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• v.10 no.2
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• pp.51-69
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• 2000

Recently, as business problems become more complicated and require more precise quantitative results, large-scale model management systems are increasingly in demand for supporting the decision-making activities. In addition, as distributed computing over networks gains popularity, departmental computing systems are gradually adopted in an organization to facilitate collaboration of geographically dispersed multiple departments. In departmental collaborative model management systems, multiple departments share common models but approach them with different user-views depending on their departmental needs. Moreover, the shared models become evolved as their structures and the corresponding data sets change due to the dynamic nature of the operating environment and the inherent uncertainty associated with the problems. In such capacity, providing the multiple departmental users with synchronized and consistent views of the models is important to improve the overall productivity. In this paper, we propose a collaborative model management framework for coordinating model change and automatic user-view update in a departmental computing environment. To do so, we describes changes in the model and their effects occurred in departmental model management environments and identifies the constructs and processes for maintaining the consistency between a shared model and its departmental user-views. Especially, in this framework, generic model concept was adopted for accommodating diverse mathematical models in a uniform way in a modelbase and object-oriented database management systems(ODBMS) for combining the model management constructs and automatic user-view update mechanisms in a single formalism. A prototype object-oriented modeling environment was developed using an ODBMS called ObjectStore and $C^{++}$ programming language on Windows NT.

• Journal of Platform Technology
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• v.12 no.1
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• pp.32-43
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• 2024

In recent years, a platform providing a Visual Programming development environment capable of 3D editing and interaction editing in an In-VR environment to quickly prototype VR/AR contents for education of VR and AR for general users and children. In the past, VR contents were mostly viewed by users. However, thanks to the rapid development of recent computing technologies, VR contents interacting with users have emerged as a device capable of tracking user behavior in a small size It was able to appear. In addition, because VR is extended to AR and MR, it can be used in all three virtual environments and requires efficient user interface(UI). In this paper, we propose UI based on eye tracking. Eye-tracking-based UI not only reduces the amount of time the user directly manipulates the controller, but also dramatically lowers the time spent on simple operations, while reducing the need for a dedicated controller by allowing multiple types of controllers to be used in combination. The proposed platform can easily create a prototype of their intended VR/AR App(or content) even for users(beginners) who do not have a certain level of knowledge and experience in 3D graphics and software coding, and share it with others. Therefore, this paper proposes a method to use VAL more effectively in a 5G environment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.3
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• pp.493-497
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• 2005

This paper is about the research of the User Agent implementation under wireless embedded environment, using SIP which is one of protocol components construct the VoIP system. The User Agent is made of the User Agent configuration block, the device thread block to control devices and the SIP stack block to process SIP messages. The device thread consists of the RTP thread and the sound lard device processing block. Futhermore, the SIP stack consist of the worker thread to process proxy events, the SIP transceiver and SIP thread to transfer and receive SIP messages. The H/W platform is a board included the Intel's XScale PXA255 processor, flash memory, SDRAM, Audio CODEC module and wireless LAN threough PCMCIA socket, furthermore a microphone and headphone is used by the audio 1/0. The system has embedded linux kernel 2.4.19. For embedded environment, the function of User Agent and SIP method is diminished. Finally, the resource of system could be reduced about $12.9\%$, compared to overall system resource, by minimizing peripherals control and excepting TCP.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.9
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• pp.3335-3356
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• 2015

In this paper, we analyze the connectivity of cognitive radio ad-hoc networks in a log-normal shadow fading environment. Considering secondary user and primary user's locations and primary user's active state are randomly distributed according to a homogeneous Poisson process and taking into account the spectrum sensing efficiency of secondary user, we derive mathematical models to investigate the connectivity of cognitive radio ad-hoc networks in three aspects and compare with the connectivity of ad-hoc networks. First, from the viewpoint of a secondary user, we study the communication probability of that secondary user. Second, we examine the possibility that two secondary users can establish a direct communication link between them. Finally, we extend to the case of finding the probability that two arbitrary secondary users can communicate via multi-hop path. We verify the correctness of our analytical approach by comparing with simulations. The numerical results show that in cognitive radio ad-hoc networks, high fading variance helps to remarkably improve connectivity behavior in the same condition of secondary user's density and primary user's average active rate. Furthermore, the impact of shadowing on wireless connection probability dominates that of primary user's average active rate. Finally, the spectrum sensing efficiency of secondary user significantly impacts the connectivity features. The analysis in this paper provides an efficient way for system designers to characterize and optimize the connectivity of cognitive radio ad-hoc networks in practical wireless environment.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.1
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• pp.125-129
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• 2010

Stateless computing supports a mobility of computing environment easily. It is becoming a major technology for securing personal user's information on shared computing environment. With the advance of virtualization technology and cloud computing, stateless computing is an essential part of personal computing environment connectivity (user's setting and data is stored in remote server or some storage, and it can be restored at any computing environment) In this paper, we propose uPC player that supports stateless computing execution environment on Windows. uPC player provides Windows operating system to user by using an uPC OS virtualization module. In this paper, we leverage how uPC player is designed and implemented for supporting a stateless computing execution environment. uPC player provides a desktop switch between host-system execution environment and uPC virtual execution environment. And it needs just one second for loading uPC virtual execution environment by using OS virtualization-based technique.