• Journal of KIISE:Information Networking
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• v.29 no.5
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• pp.562-572
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• 2002

Distributed object technologies have become popular in developing distributed systems. Although such middleware platforms as DSOM, DCOM, CORBA and Java RMI ease the development of distributed applications, they do not directly improve the reliability and the availability of these applications. Because the task of developing fault-tolerance techniques for distributed object paradigms is often complicated and error-prone, there is a great need for a development toolkit that enhances the reliability and the availability of distributed objects. In this paper, we propose a fault-tolerant distributed middleware system based on RMI, called IMMORTAL. We use a log-based rollback-recovery mechanism for supporting reliable distributed computing. Through a series of experiments, we observe that benchmark applications on the IMMORTAL tolerate hardware and software failures and evaluate its performance and scalability.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.649-652
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• 2007

Recently, it is increasing the interest in previous web and web 2.0 which mean differentiation. The previous system is typical Static web based on client and server model, while web 2.0 mean next generation web which web change and evolve fundamentally. In this paper, I suggest that the module on RSS reader available under web 2.0 standards. A currently used RSS feed do correct the part distortion which can be possible resolve the encoding problem of Hanguel and third-world language. The suggested module is implemented using Ajax. I developed the module for the use of effective contents on web 2.0 through the DragBox module based on the programming on mobility of Ajax and the design and implementation of automatic update module of RSS feed.

• Journal of the Korea Convergence Society
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• v.10 no.12
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• pp.71-80
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• 2019

DevOps is a combining which means giving a diverse environments for software development and operations through whole software lifecycle. The key value of the proposed DevOps platform is the fast and stable service capability for a software development and operation environment. To do this, the DevOps gives pre-embedded 7 programming languages-Java, C/C++, Python, PHP, Ruby, Node.js, goLang and 7 service frameworks - Korea eGov Framework, Spring, Struts, Django, Laravel, Rails, Express. With the DevOps platform, it is possible to develop a software and also to build and distribute operation packages directly with the Linux containers. In this paper, the performance evaluation for a compile time, a distribution time and a processing capability is will be also proved. Though the performance evaluation, this paper shows capabilities of the proposed DevOps for Cloud services with commercial service level, prospectively.

• Wind and Structures
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• v.23 no.2
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• pp.109-125
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• 2016

Flow interference is investigated between two tripped cylinders of identical diameter D at stagger angle ${\alpha}=0^{\circ}{\sim}180^{\circ}$ and gap spacing ratio $P^*$ (= P/D) = 0.1 ~ 5, where ${\alpha}$ is the angle between the freestream velocity and the line connecting the cylinder centers, and P is the gap width between the cylinders. Two tripwires, each of diameter 0.1D, were attached on each cylinder at azimuthal angle ${\beta}={\pm}30^{\circ}$, respectively. Time-mean drag coefficient ($C_D$) and fluctuating drag ($C_{Df}$) and lift ($C_{Lf}$) coefficients on the two tripped cylinders were measured and compared with those on plain cylinders. We also conducted surface pressure measurements to assimilate the fluid dynamics around the cylinders. $C_D$, $C_{Df}$ and $C_{Lf}$ all for the plain cylinders are strong function of ${\alpha}$ and $P^*$ due to strong mutual interference between the cylinders, connected to six interactions (Alam and Meyer 2011), namely boundary layer and cylinder, shear-layer/wake and cylinder, shear layer and shear layer, vortex and cylinder, vortex and shear layer, and vortex and vortex interactions. $C_D$, $C_{Df}$ and $C_{Lf}$ are very large for vortex and cylinder, vortex and shear layer, and vortex and vortex interactions, i.e., the interactions where vortex is involved. On the other hand, the interference as well as the strong interactions involving vortices is suppressed for the tripped cylinders, resulting in insignificant variations in $C_D$, $C_{Df}$ and $C_{Lf}$ with ${\alpha}$ and $P^*$. In most of the (${\alpha}$, $P^*$ ) region, the suppressions in $C_D$, $C_{Df}$ and $C_{Lf}$ are about 58%, 65% and 85%, respectively, with maximum suppressions 60%, 80% and 90%.

• Journal of the Korea Convergence Society
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• v.9 no.9
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• pp.1-8
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• 2018

It is a key role in leading and activating coding education as a process to solve problems creatively to produce and provide the educational contents on the basis of 3D printing. In this paper, we develop a variety of fusion contents to use 3D printing and 8bit MCU base control board which provides specific functions through Arduino. The developed control program conducts various packet monitoring more than ten times per a second, supporting intrinsically full duplex. In addition, communication protocol optimized in conveying a lot of information enables to control different contents. The contents produced with the control board and 3D printing are useful as a programming education tool to train the principle and the concept of coding.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.975-977
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• 2013

Arduino is for design based on open source prototyping platform, artist, designer, hobby activists, etc, i has been designed for all those who are interested in the environment construct. Arduino adventage you can easily create applications hardware, without deep knowledge about the hardware. Configuration of arduino using AVR microcontroller ATmage 168, software to action arduino using arduino program, MATLAB, Processing. Arduino is open source base, you can hardware production directly and using shield additionally, the arduino can be combined. Processing iis open source. You can 2D, 3D, PDF output, using P3D and OpenGL graphics. Also you can check by running a stand-alone application. Through a combination of Arduino, library support, such as sound, video, and computer vision can be expanded, this program is the Android phone and iPhone programming. In this paper, sortware was used for Processing, hardware was used for arduino MegaADK board, After making easy 2axis game, using the software and hardware verification.

• Korean Journal of Ecology and Environment
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• v.43 no.1
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• pp.161-167
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• 2010

In this study, we implemented an experimental approach of ecological model development in order to emphasize the importance of input variable selection with respect to time-delayed arrangement between input and output variables. Time-series modeling requires relevant input variable selection for the prediction of a specific output variable (e.g. density of a species). Inadequate variable utility for input often causes increase of model construction time and low efficiency of developed model when applied to real world representation. Therefore, for future prediction, researchers have to decide number of time-delay (e.g. months, weeks or days; t-n) to predict a certain phenomenon at current time t. We prepared a total of 3,900 equation models produced by Time-Series Optimized Genetic Programming (TSOGP) algorithm, for the prediction of monthly averaged density of a potamic phytoplankton species Stephanodiscus hantzschii, considering future prediction from 0- (no future prediction) to 12-months ahead (interval by 1 month; 300 equations per each month-delay). From the investigation of model structure, input variable selectivity was obviously affected by the time-delay arrangement, and the model predictability was related with the type of input variables. From the results, we can conclude that, although Machine Learning (ML) algorithms which have popularly been used in Ecological Informatics (EI) provide high performance in future prediction of ecological entities, the efficiency of models would be lowered unless relevant input variables are selectively used.

• Journal of Digital Contents Society
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• v.18 no.4
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• pp.747-751
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• 2017

The log has variable informations that are important and necessary to manage a network when accessed to network servers. These informations are used to reduce a cost and efficient manage a network through the meaningful prediction information extraction from the amount of user access. And, the network manager can instantly monitor the status of CPU, memory, disk usage ratio on network using the SNMP. In this paper, firstly, we have accumulated and analysed the 6 network logs and extracted the informations that used to predict the amount of user access. And then, we experimented the prediction simulation with the time series analysis such as moving average method and exponential smoothing. Secondly, we have simulated the usage ration of CPU, memory, and disk using Xian SNMP simulator and extracted the OID for the time series prediction of CPU, memory, and disk usage ration. And then, we presented the visual result of the variable experiments through the Excel and R programming language.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.6
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• pp.147-154
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• 2015

Recently agile development process became increasing effectiveness, quality, attention to experts in customer satisfaction, as evidenced in this methodology when selecting projects promoting productive efficiency. With regard to contemporary needs and user requirements on the methodology selected to meet this paper is the product based Cross functional team suggested methodology Feature Team model to solve problems of this model, and organizing the Cross functional team, this team but this outcome (product) basis, were examined for the model that points to progress the development across multiple product as a functional unit, value-driven agile project through the Skills-based model and proposed a difference. And it examined the Agile Maturity metrics. PRINCE2 Agile Health-check entries future development direction of Agile techniques is a requirement of the project outset has studied the subject objective evaluation by the assumption that they can be changed at any time, not fixed this way and for the project team through research The proposed.

• The Transactions of the Korea Information Processing Society
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• v.3 no.6
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• pp.1522-1533
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• 1996

This paper presents a programming environment for the edition and verification of specification language SDL. It is implemented in the Concerto software factory, which has been as a support for the development of real size software. Concerto is a software factory designed for application development in the fields of computer communication protocols or real time system. It offers various kinds of tools to produce software, organize this production and automate it. Concerto allows a smooth integration of various formalism such as the C and $C^{++}$, languages, structured documentation, HOOD methodology (Hierarchical Object Orient Design). In this paper, as an important tools in the process of communication protocol software development, we describe fist describe the principles of this environment, then we illustrate its application by means of a simple example, the Inres protocol. Moreover, we study how hypertext mechanism of Concert to create logical links between a protocol and its asscoiated service.