• Journal of Electrical Engineering and Technology
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• v.9 no.1
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• pp.60-70
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• 2014

This paper discusses the impacts of large scale grid-connected wind farm equipped with permanent magnet synchronous generator (PMSG) on power system small signal stability (SSS) incorporating wind generation uncertainty and volatility. Firstly, a practical simplified PMSG model with rotor-flux-oriented control strategy applied is derived. In modeling PMSG generator side converter, the generator-voltage-oriented control strategy is utilized to implement the decoupled control of active and reactive power output. In modeling PMSG grid side converter, the grid-voltage-oriented control strategy is applied to realize the control of DC link voltage and the reactive power regulation. Based on the Weibull distribution of wind speed, the Monte Carlo simulation technique based is carried out on the IEEE 16-generator-68-bus test system as benchmark to study the impacts of wind generation uncertainty and volatility on small signal stability. Finally, some preliminary conclusions and comments are given.

• The Mathematical Education
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• v.53 no.3
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• pp.357-381
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• 2014

This study analyzed the cases of three teacher communities participating in an innovative professional development program and clarified the characteristics and the process of lessons for mathematics-oriented convergence that were developed and applied during the program. Each of the teacher communities designed and implemented lessons according to the context of each community and the concept of lessons for mathematics-oriented convergence were developed and refined. The lessons developed by the three teacher communities were characterized as convergence problem posing lessons using technology, convergence of various subject content focused on mathematical concepts through team teaching, and convergence lessons according to students' achievement levels. The program contributed to teacher community activities by proving sustainable professional development in the area of convergence education, a connection between the content of their professional development and the context of the field, and opportunities for active participation in the process of developing and implementing the convergence lessons.

• Journal of the Korea Society for Simulation
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• v.8 no.1
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• pp.1-18
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• 1999

Current CIM systems need to correspond flexibly to the frequent change of demands of the customers and the fast changing informations about the production environment. The demands have brought forth CIM systems developed using object-oriented technology, with reusability, expansibility, and flexibility for the system components. Due to the fact that the OO-CIM system has been developed based on an incomplete data, the constructed system must be implemented to the actual surroundings to see how pertinent it is. Hence, this paper presents an OO-simulator as a means to evaluate the pertinency and the efficiency of the developed CIM system. The OO-simulator can determine the problems likely to occur when a developed CIM system is implemented to the actual site and evaluate the efficiency beforehand. Such properties will decrease the cost of CIM system development and increase the reliability of the system. This paper presents a framework for an OO-simulator composed of a virtual factory component embodying the characteristics of a virtual factory, a connector component for the interface between the CIM system and the simulator, a configuration component for modeling the constituent structure of the CIM system, and a timer component in charge of the time advance for the simulation.

• International journal of advanced smart convergence
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• v.7 no.3
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• pp.79-91
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• 2018

Service Oriented Architecture (SOA) has appeared as an absorbing architectural approach that empowers the available systems to reveal their performance in the act of services, without creating important changes to the systems. This approach, due to its flexibility of adoption, has been widely recognized as an appropriate approach for implementing in organizations by many scholars and practitioners. Though, there are many studies that depict success factors of SOA; at the same time a few minor cases of failure has also been reported in the literature. In spite of the availability of rich material on SOA (in general), there is no systematic literature review on the potential aspect of SOA adoption factors. Hence, this article presents a systematic review of existing studies related to the SOA adoption and its success and failure factors from 2009 to 2015. The principle purpose of the study is to bring forward the existing issues and share our findings with researchers. Moreover, the findings of this paper would help IT experts in organizations to concentrate on the key factors highlighted in this study, so that they could decide whether it is advisable to adopt SOA or not in their context.

• Journal of Information Technology Applications and Management
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• v.14 no.3
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• pp.49-77
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• 2007

Role-based access control (RBAC) models are recently receiving considerable attention as a generalized approach to access control. In line with the increase in applications that deal with spatial data. an advanced RBAC model whose entities and constraints depend on the characteristics of spatial data is required. Even if some approaches have been proposed for geographic information systems. most studies focus on the location of users instead of the characteristics of spatial data. In this paper. we extend the traditional RBAC model in order to deal with the characteristics of spatial data and propose new spatial constraints. We use the object-oriented modeling based on open GIS consortium geometric model to formalize spatial objects and spatial relations such as hierarchy relation and topology relation. As a result of the formalization for spatial relations. we present spatial constraints classified according to the characteristics of each relation. We demonstrate our extended-RBAC model called OOGIS-RBAC and spatial constraints through case studies. Finally. we compare our OOGIS-RBAC model and the DAC model in the management of access control to prove the efficiency of our model.

• Journal of Information Technology Services
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• v.16 no.1
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• pp.119-138
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• 2017

Mobile easy payment is a term for using mobile devices to facilitate financial transactions. Mobile easy payment is a quickly emerging practice, supported by the dramatic increase of mobile phone or device users around the world. The purpose of this study is to classify user's group of the mobile easy payment service by their lifestyle based on I-VALS type and to investigate differences in usage behavior among the user groups. For empirical study, a questionnaire survey was carried out with users of mobile easy payment services using the Internet from June 7 to 10 in 2016. We conducted factor analysis for I-VALS, usage factors, satisfaction factors. We also performed cluster analysis for group classification, and analysis of variance, cross analysis to compare the different usage behavior among the user groups. In analysis results, first three cluster appeared including "ICT task-oriented group", ICT positive and socialities oriented group", "ICT leader-oriented group". Second, it was found significant differences among the clusters about factor of "easy of use", "securities", "universality", "satisfaction". Third, we showed that there were significant differences in time first used the service. Based on these findings, we provide practical implications. Results of our study can be expected to provide the basis of differentiated marketing strategy of mobile easy payment services.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.27 no.4
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• pp.33-41
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• 2004

This study examines the relationship between multiple sales force management practices and performance within each of Miles & Snow (1978)'s strategy types and Walker & Ruekert (1987)'s strategy types. The findings are as follows : First, Prospectors seem to be associated with increased performance when they are utilizing a relationship selling strategy, internal sales force, moderate levels of supervision, outcome-based control system and incentive-oriented compensation system. Second, Analyzers seem to be associated with increased performance when they are utilizing a relationship selling strategy, internal sales force, outcome-based control system to deal with the instability in their strategic focus. Third, Low Cost Defender seem to be associated with increased performance when they are utilizing a relationship selling strategy, external sales force, low levels of supervision, outcome-based control system and salary-oriented compensation system. Fourth, Differentiated Defenders seem to be associated with increased performance when they are utilizing a relationship selling strategy, high levels of supervision, balanced (outcome+behavior) control system and salary-oriented compensation system.

• The Journal of Information Systems
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• v.28 no.2
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• pp.1-23
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• 2019

Purpose This study exploratory investigated the effects of the fit between forms of knowledge management(KM) strategy and types of information technology(IT) capability on the kinds of innovations such as product and process innovations. In this study, the openness of innovations that affects the innovations of a firm is considered. Design/methodology/approach For this empirical study, 104 manufacturing firms' data were finally collected through field survey. For the analysis of the data, cluster analysis and multiple regression analysis were employed. Findings This study demonstrated that when a system-oriented KM strategy is adopted, IT flexibility, which supports the implementation of a system-oriented strategy, is highly employed and utilized. It was also found that under a dynamic KM strategy, both IT integration and IT flexibility are highly employed. For the innovation of a firm, it was found that when a system-oriented strategy is employed and the flexibility of IT is highly adopted, the levels of product innovation are enhanced. Under a dynamic strategy, when the degrees of IT integration and IT flexibility are high, high levels of product and process innovations were empirically found. The impact of innovation openness on the innovations of a firm were partially demonstrated. Finally, the positive impact of the innovations on the improvement of performance in manufacturing firms were demonstrated.

• Journal of information and communication convergence engineering
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• v.17 no.1
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• pp.67-73
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• 2019

In the current era of digital technology, and with the help of existing software, digital photo manipulation is becoming easier and faster. One example of this is the development of powerful image processing software that makes it easy for a digital image to be manipulated and edited. It is therefore very important to protect and maintain public trust in digital images. Several methods have been developed to detect image manipulation. In this paper, we compare two methods for detecting image duplication due to copy-move actions, namely the polar coordinate system and the histogram of oriented gradients methods. The former is a method based on the transfer of a Cartesian image to a polar form, making it easy to tell whether there are objects that have undergone a copy/move in an image, while the latter is a method for retrieving information related to the distribution, which uses a target in the local area as a tool to represent the shape of the target. We compare the accuracy, speed and memory usage of these two methods.

• Korean Journal of Materials Research
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• v.29 no.5
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• pp.277-281
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• 2019

The objective of this research is to evaluate the effect of adhesive types on dimensional stability of bamboo-oriented particleboard. The materials used in this research are bamboo tali(Gigantochloa apus J.A & J.H. Schult. Kurz), UF/MDI(8, 10, 12 % level), and MF, MDI, and PF at 7 % level. Particle and adhesive are mixed using a blending machine; then, mat forming and hot pressing processes are performed using adhesive-suitable temperature and time references. MDI resin is set at $160^{\circ}C$ temperature for 5 minutes. PF resin and MF resin are pressed at $170^{\circ}C$ for 10 minutes, and $140^{\circ}C$ for 10 minutes, respectively, while UF/MDI sets at temperature of $140^{\circ}C$ for 10 minutes. The results show that particleboard using PF resin produces the lowest thickness swelling value. The particleboard using UF/MDI resin also produces good response for thickness swelling value. Interesting things happen in that UF/MDI adhesive produces a thickness swelling value better than that of MDI resin. FTIR analysis on particleboard bonded by UF/MDI resin combination shows the presence of carbonyl group C=O vibration on multi substitution of urea at wave number of around $1,700cm^{-1}$.