• Journal of KIISE
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• v.42 no.8
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• pp.1057-1064
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• 2015

The tactical network is system based on wireless networking technologies that ties together surveillance reconnaissance systems, precision strike systems and command and control systems. Several alternative paths exist in the network because it is connected as a grid to improve its survivability. In addition, the network topology changes frequently as forces and combatants change their network access points while conducting operations. However, most Internet routing standards have been designed for use in stable backbone networks. Therefore, tactical networks may exhibit a deterioration in performance when these standards are implemented. In this paper, we propose Priority based Multi-Path routing with Local Optimization(PMPLO) for a tactical backbone network. The PMPLO separately manages the global and local metrics. The global metric propagates to other routers through the use of a routing protocol, and it is used for a multi-path configuration that is guaranteed to be loop free. The local metric reflects the link utilization that is used to find an alternate path when congestion occurs, and it is managed internally only within each router. It also produces traffic that has a high priority privilege when choosing the optimal path. Finally, we conducted a simulation to verify that the PMPLO can effectively distribute the user traffic among available routers.

• Journal of Advanced Navigation Technology
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• v.16 no.6
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• pp.988-996
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• 2012

Assuming perfect channel state information (CSI), the conventional interference alignment (IA) algorithm in the uplink cellular system suppresses inter-cell interference (ICI) by aligning ICI to a randomly selected reference vector. However, IA in practice relies on limited feedback between base stations and users, resulting in residual ICI. In this paper, we propose the optimization of the reference vector that minimizes the upper-bound of residual ICI power. Secondly, the iterative IA that designs the direction of transmit and receive filter is proposed to minimize the residual ICI as well as maximize the desired signals. Moreover, we propose the user scheduling method combined with proposed IA schemes which provides the multiuser diversity gain in multi-cell environments. Finally, the performance gain of the proposed IA algorithms compared with the existing IA are analyzed and demonstrated by simulation results.

• Journal of Korean Institute of Industrial Engineers
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• v.39 no.1
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• pp.46-54
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• 2013

Recently, the marine leisure industry has begun to make a mark on the growth engines of the Korean economy. Hence, various government research projects are in progress to catch up with the fundamental yacht technologies of advanced countries. Research on the integrated management technologies of sail yachts is carried out as a part of those projects. Work Breakdown Structure (WBS) is a basic architecture for robust and high-level management systems. In this paper, we suggest a product-oriented Yacht Work Breakdown Structure (YWBS). General WBS has a drawback in that it can only follow the targeted purpose, but YWBS allows for a generic WBS approach. This concept allows us to apply WBS to multi-purpose uses. The YWBS is used as an infrastructure in information management and for data relationships in sail yacht management systems. YWBS is designed and managed by a web application, and the system is implemented with a website as a user interface. This application has not only a design function, but also a data transfer function that is based on the Microsoft Silverlight platform, a kind of Rich Internet Application (RIA) technology. Using this application, YWBS designers can communicate with the management system without added tasks like as uploading and updating.

• Journal of Communications and Networks
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• v.18 no.5
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• pp.837-845
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• 2016

Providing a customer with tailored location-based services (LBSs) is a fundamental problem. For location-estimation techniques with radio-based measurements, LBS applications are widely available for mobile devices (MDs), such as smartphones, enabling users to run multi-task applications. LBS information not only enables obtaining the current location of an MD but also provides real-time push-pull communication service. For indoor environments, localization technologies based on radio frequency (RF) pattern-matching approaches are accurate and commonly used. However, to survey radio information for pattern-matching approaches, a considerable amount of time and work is spent in indoor environments. Consequently, in order to reduce the system-deployment cost and computing complexity, this article proposes an indoor positioning approach, which involves using Asus Xtion to facilitate capturing RF signals during an offline site survey. The depth information obtained using Asus Xtion is utilized to estimate the locations and predict the received signal strength (RF information) at uncertain locations. The proposed approach effectively reduces not only the time and work costs but also the computing complexity involved in determining the orientation and RF during the online positioning phase by estimating the user's location by using a smartphone. The experimental results demonstrated that more than 78% of time was saved, and the number of samples acquired using the proposed method during the offline phase was twice as much as that acquired using the conventional method. For the online phase, the location estimates have error distances of less than 2.67 m. Therefore, the proposed approach is beneficial for use in various LBS applications.

• Journal of the Korea Computer Industry Society
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• v.7 no.4
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• pp.427-436
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• 2006

State-space method for the analysis of the dynamic characteristics of a body motion is set up as mathematical tool for the solution of differential equation by computer. Representation of a system is described as a simple form of matrix calculation and unique form of model is available for the linear or nonlinear, time variant or time invariant, mono variable or multi variable system etc. For the analysis of state-space method a complicated vector calculation is required, but this analysis can be simplified with the specific functions of a software package. Recently as the Graphical User Interface softwares are well-developed, then it is very simplified to execute the simulation of the dynamic characteristics for the state-space model with the interactive graphics treatment. The purpose of this study is to developed the simulator for the educational analysis of the dynamic characteristics of body motion, and for the analysis of the longitudinal dynamic characteristics of an aircraft that is primarily to design the simulator for the analysis of the transient response of an aircraft longitudinal stability.

• Structural Engineering and Mechanics
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• v.67 no.6
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• pp.643-658
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• 2018

In this paper, we introduce a new framework for running the finite element (FE) packages inside an online Loop together with MATLAB. Contrary to the Hardware-in-the-Loop techniques (HiL), in the proposed Software-in-the-Loop framework (SiL), the FE package represents a simulation platform replicating the real system which can be out of access due to several strategic reasons, e.g., costs and accessibility. Practically, SiL for sophisticated structural design and multi-physical simulations provides a platform for preliminary tests before prototyping and mass production. This feature may reduce the new product's costs significantly and may add several flexibilities in implementing different instruments with the goal of shortlisting the most cost-effective ones before moving to real-time experiments for the civil and mechanical systems. The proposed SiL interconnection is not limited to ABAQUS as long as the host FE package is capable of executing user-defined commands in FORTRAN language. The focal point of this research is on using the compiled FORTRAN subroutine as a messenger between ABAQUS/CAE kernel and MATLAB Engine. In order to show the generality of the proposed scheme, the limitations of the available SiL schemes in the literature are addressed in this paper. Additionally, all technical details for establishing the connection between FEM and MATLAB are provided for the interested reader. Finally, two numerical sub-problems are defined for offline and online post-processing, i.e., offline optimization and closed-loop system performance analysis in control theory.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.30-34
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• 2009

Recently, systems providing the interaction different according to an interval between a user and the display were developed in order to construct the ambient or the ubiquitous computing environment. Therefore, we propose a new type of spatial interaction system; our main goal is to provide the interactive domain in the large-scale ambient display environment. So, we divide into two zones of interaction dependent on the distance from the interaction surface interactive zone and ambient zone. In interactive zone, the users can approach the interaction surface and interact with natural hand-touch. When the users are outside the range of the interactive zone, the display shows only general information. Therefore, this system offers the various interactions and information to users in the ubiquitous ambient environment.

• The Transactions of the Korea Information Processing Society
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• v.5 no.1
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• pp.73-85
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• 1998

Today's Software Systems are becoming bigger, larger and more complex than ever before. To develop largerscale projects, it is required that many experts of different fields participate and cooperate in the same project. So, it is an applied area of CSCW(Computer Supported Cooperative Works} that centers around methodologies and tools that enable cooperative works by geographically distributed people engaged in all aspects of product development. In this paper, we designed a multi-user cooperative works platform, SPACE(Software Platform for distributed Application sharing under Cooperative Environment} as a infrastructure that support to CSCW based system development for telecommunication and information system. SPACE has a fully distributed architecture under Windows 95 environment, has an application sharing mechanism enabling collaborative use of mteractive application adapt to a mixed GUI sharing technology which capture GUI and screen information, and also, an event sharing technology that has a replicated architecture.

• Journal of Convergence for Information Technology
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• v.8 no.5
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• pp.69-75
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• 2018

The purpose of access control is to prevent computing resources from illegal behavior such as leakage, modification, and destruction by unauthorized users. As the cloud computing environment is expanded to resource sharing services using virtualization technology, a new security model and access control technique are required to provide dynamic and secure cloud-based computing services. The virtualization management convergence access control model provides a flexible user authorization function by applying the dynamic privilege assignment function to the role based access control mechanism. In addition, by applying access control mechanism based on security level and rules, we solve the conflict problem in virtual machine system and guarantee the safeness of physical resources. This model will help to build a secure and efficient cloud-based virtualization management system and will be expanded to a mechanism that reflects the multi-level characteristics.

• The Journal of Society for e-Business Studies
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• v.12 no.1
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• pp.151-166
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• 2007

As the number of users who are involved in a business process increases, it becomes imperative to effectively control their privileges of accessing sensitive data and information which are usually easily obtained by BPM system. Traditional RBAC (Role-based Access Control) model was first introduced to provide a logical framework to prevent unauthorized users from obtaining confidential, but in more dynamic environment such as B2B and SCM process, it usually lacks in capability of addressing such issues as configurability, customizability, or scalability of user privileges. In this study, we have proposed a privilege-template based RBAC model that can address such issues effectively. We also provided a design of the RBAC model along with illustrative examples and pseudo codes that can be used for implementing a prototype system.