• Journal of Information Technology and Architecture
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• v.11 no.3
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• pp.321-332
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• 2014

In this paper we propose a new notion of predictable flags type of authorization for controlling access to XML documents. By using predictable flags, we are able to efficiently detect conflicts between existing authorizations and new authorizations to be added. XML documents have an element-composition hierarchical structure in that a higher level element consists of multiple lower level sub-elements. Many XML documents systems have used the notion of implicit authorization that grants authorizations to an element and the all descendants to avoid the overhead caused by explicitly storing all authorization for each element. When we grant an authorization on an element in the XML documents, the implicit authorization method is inefficient in determining the conflicts since it needs to examine all authorizations on the descendants of that element. In contrast, our mechanism using predictable flags has the advantage of detecting the conflicts immediately at the element where an explicit authorization is to be granted.

• 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 Institute of Information Security & Cryptology
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• v.29 no.2
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• pp.261-273
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• 2019

Recently, with the development of IT technology, there is an increasing interest in cloud services as the number of users using mobile devices such as mobile phones and tablets is increasing. However, there is a need for techniques to control or control various methods of accessing data as the user's service demands increase. In this paper, we propose a dual key based user authentication model that improves the user 's authentication efficiency by using two keys (secret key and access control key) to access the users accessing various services provided in the cloud environment. In the proposed model, the operation process and the function are divided through the sequence diagram of the algorithms (key generation, user authentication, permission class permission, etc.) for controlling the access right of the user with dual keys. In the proposed model, two keys are used for user authentication and service authorization class to solve various security problems in the cloud service. In particular, the proposed model is one of the most important features in that the algorithm responsible for access control of the user determines the service class of the user according to the authority, thereby shortening the management process so that the cloud administrator can manage the service access permission information of the user.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.3
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• pp.330-338
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• 2016

Phase change memory (PCM) has been studied as an emerging memory technology for last-level cache (LLC) due to its extremely low leakage. However, it consumes high levels of energy in updating cells and its write endurance is limited. To relieve the write pressure of LLC, we propose a delta value indicator (DVI) by employing a small cache which stores the difference between the value currently stored and the value newly loaded. Since the write energy consumption of the small cache is less than the LLC, the energy consumption is reduced by access to the small cache instead of the LLC. In addition, the lifetime of the LLC is further extended because the number of write accesses to the LLC is decreased. To this end, a delta value indicator and controlling circuits are inserted into the LLC. The simulation results show a 26.8% saving of dynamic energy consumption and a 31.7% lifetime extension compared to a state-of-the-art scheme for PCM.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.3
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• pp.591-597
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• 2009

The problem of controlling a finite-state asynchronous sequential machine is examined. The considered machine is governed by input/output control, where access to the state of the machine is not available. In particular, disturbance inputs can infiltrate into the asynchronous machine and provoke unauthorized state transitions. The control objective is to use output feedback to compensate the machine so that the closed-loop system drive the faulty asynchronous machine from a failed state to the original one. Necessary and sufficient condition for the existence of appropriate controllers are presented in a theoretical framework. As a case study, the closed-loop system of an asynchronous machine with the proposed control scheme is implemented in VHDL code.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.239-240
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• 2012

When users access to use the computing resources in the cloud, they expect specific quality of service (QoS) which should be guaranteed by the service provider. Meanwhile, the service provider should adopt proper schemes to enhance the resource utilization. In this thesis, we propose the MapChem-Broker which aims to satisfy users' QoS requirements as well as enhance the resource utilization by controlling the provision of VM resources in the cloud. On the experimental cloud testbed, we compare the proposed scheme with an existing one for VM resource provisioning. Results show that the proposed scheme outperforms the existing one.

• Journal of Korea Multimedia Society
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• v.20 no.2
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• pp.396-403
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• 2017

In recent years, the use of touch screens has expanded, and devices such as remote controllers have been developed in various ways to control and access contents at long range. The wireless-based touch screen is used in classroom, seminar room, and remote video conversation in addition to the TV remote control. The purpose of the study is to design a smart phone-based intuitive interface that can perform the role of a wireless mouse and a wireless keyboard at range using Bluetooth and to develop an application that integrates functions of a mouse and a keyboard. Firstly, touch interaction model for controlling software such as PowerPoint by connecting to a general PC on a smart phone has been studied. The most simple touch operation interface is used to reproduce the function of existing devices and design more simply. The studies of the extension of interfaces with various functions are important, but development of optimized interfaces for users will become more important in the future. In this sense, this study is valuable.

• Journal of Korea Foundry Society
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• v.26 no.1
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• pp.27-33
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• 2006

Phase evolutions involving nucleation stages together with diffusional growth have been examined in order to provide a guideline for determining rate limiting stages during phase evolutions. In multiphase materials systems in coatings, composites or multilayered structures, diffusion treatments often result in the development of metastable/intermediate phases at the reaction interfaces. The development of metastable phases during solid state interdiffusion demonstrates that the nucleation reaction can be one controlling factor. Also, the concentration gradient and the relative magnitudes of the component diffusivities provide a basis for a phase selection and the application of a kinetic bias strategy in the phase selection. For multicomponent alloy systems, the identification of the operative diffusion pathway is central to control phase formation. Experimental access to the nucleation and growth stage is discussed in thin film multi layers and bulk samples.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.497-499
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• 2015

According to the rapid progress of the altitude information society and various sensor technologies, The role of information and communication systems became important during social activities. In this paper, It is measured access and availability alongside parking and availability using an ultrasonic sensor and a pressure sensor. And the measuring data is sent to the controller by using the PLC (Power Line Communication). And it is implementing the parking management system made secure by controlling the LED and LCD with the received data.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.2
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• pp.53-60
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• 2014

The recent electric power shortage has led to the vigorous study for energy conservation in the many different fields. In this paper, cell zooming technology, which can reduce the energy loss at the base stations controlling the transmission power of the stations depending on the changing trffic density for reduce energy consumption that occurs when there is little or no trffic in the service area, is proposed and energy conservation is confirmed by comparing base stations' service scenario depending on traffic change.