• Ocean Systems Engineering
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• v.5 no.3
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• pp.139-160
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• 2015

The global performance of the 5MW OC4 semisubmersible floating wind turbine in random waves was numerically simulated by using the turbine-floater-mooring fully coupled and time-domain dynamic analysis program FAST-CHARM3D. There have been many papers regarding floating offshore wind turbines but the effects of second-order wave-body interactions on their global performance have rarely been studied. The second-order wave forces are actually small compared to the first-order wave forces, but its effect cannot be ignored when the natural frequencies of a floating system are outside the wave-frequency range. In the case of semi-submersible platform, second-order difference-frequency wave-diffraction forces and moments become important since surge/sway and pitch/roll natural frequencies are lower than those of typical incident waves. The computational effort related to the full second-order diffraction calculation is typically very heavy, so in many cases, the simplified approach called Newman's approximation or first-order-wave-force-only are used. However, it needs to be justified against more complete solutions with full QTF (quadratic transfer function), which is a main subject of the present study. The numerically simulated results for the 5MW OC4 semisubmersible floating wind turbine by FAST-CHARM3D are also extensively compared with the DeepCWind model test results by Technip/NREL/UMaine. The predicted motions and mooring tensions for two white-noise input-wave spectra agree well against the measure values. In this paper, the numerical static-offset and free-decay tests are also conducted to verify the system stiffness, damping, and natural frequencies against the experimental results. They also agree well to verify that the dynamic system modeling is correct to the details. The performance of the simplified approaches instead of using the full QTF are also tested.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.6 no.4
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• pp.341-349
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• 2016

To meet the requirements in the global age, the necessity and importance of global education in the field of education is rapidly increasing. However, according to the viewpoint on global education, a general consensus of its definition and model is not clear yet and the substantial outcome falls short of our expectation due to high cost, low effectiveness, and lack of persistency in the process of global education. Furthermore, there has been little research on global education for fostering global capabilities of pre-teachers. In this research, we compared and analyzed the ongoing global education programs for training global teachers in domestic universities. Also, through a study on IT fusion education system for tackling the difficulties in global education, we examined appropriate IT fusion education methods. In particular, beased on big data analysis techniques, we presented a recommendation system to complete a global curriculum, which can help a dual-degree or exchange student program.

• The Transactions of the Korea Information Processing Society
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• v.7 no.3
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• pp.879-890
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• 2000

Designing a multilevel database application is a complex process, and the entities and their associated security levels must be represented using an appropriate model unambiguously. It is also important to capture the semantics of a multilevel databse application as accurate and complete as possible. Owing to the focus of the IDEA Methodology for designing the non-secure database applications on the data-intensive systems, the Object Model describes the static structure of the objects in an application and their relationships. That is, the Object Model in the IDEA Methodology is an extended Entity-Relationship model giving a static description of objects. The IDEA Methodology has not been developed the multilevel secure database applications, but by using an existing methodology we could take advantage of the various techniques that have already been developed for that methodology. That is, this way is easier to design the multilevel secure schema than to develop a new model from scratch. This paper adds the security features 새？ Object Model in the IDEA Methodology, and presents the transformation from this model to a multilevel secure object oriented schema. This schema will be the preliminary work which can be the general scheme for the automatic mapping to the various commercial multilevel secure database management system such as Informix-Online/Secure, Trusted ORACLE, and Sybase Secure SQL Server.

• The Journal of Korean Philosophical History
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• no.54
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• pp.243-272
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• 2017

The final purpose of this study is to construct new education model through the modernization of traditional education. Our citizenship education model is expected to facilitate the democratic personality and comprise the political education program. To achieve our research project, this paper have tried to reinterpret and categorize diverse the normative, political, ideal meaning of tradition. The modernization of traditional virtue and capability is the main source of democratical citizenship against liberal representative democracy. In this context, Our education model consists of the structure of educational system, the principle of operation and the role of subject, the method of teaching through the consilience of East and West educational philosophy and practice. According to our approach to overcome and the real problems of education, modern 'Sunbei' class model can enable to form community ethics and competence. Furthermore, our new class model will contribute to becoming a democratic citizen of student and the development of Korean democracy in the future. The order of discussion in this paper runs as follows. Firstly, we will investigate into dynamic change of the traditional value on the basis of the political perspective and seek the possibility of modern reinterpretation of traditional capability. Finally, we will complete new education model including both western value and Korean traditional value and the applicable to class teaching.

• Asia pacific journal of information systems
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• v.19 no.4
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• pp.77-100
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• 2009

Information Systems (IS) is an essential tool for any organizations. The last decade has seen an increasing body of knowledge on IS usage. Yet, IS often fails because of its misuse or non-use. In general, decisions regarding the selection of a system, which involve the evaluation of many IS vendors and an enormous initial investment, are made not through the consensus of employees but through the top-down decision making by top managers. In situations where the selected system does not satisfy the needs of the employees, the forced use of the selected IS will only result in their resistance to it. Many organizations have been either integrating dispersed legacy systems such as archipelago or adopting a new ERP (Enterprise Resource Planning) system to enhance employee efficiency. This study examines user resistance prior to the adoption of the selected IS or ERP system. As such, this study identifies the importance of managing organizational resistance that may appear in the pre-adoption context of an integrated IS or ERP system, explores key factors influencing user resistance, and investigates how prior experience with other integrated IS or ERP systems may change the relationship between the affecting factors and user resistance. This study focuses on organizational members' resistance and the affecting factors in the pre-adoption context of an integrated IS or ERP system rather than in the context of an ERP adoption itself or ERP post-adoption. Based on prior literature, this study proposes a research model that considers six key variables, including perceived benefit, system complexity, fitness with existing tasks, attitude toward change, the psychological reactance trait, and perceived IT competence. They are considered as independent variables affecting user resistance toward an integrated IS or ERP system. This study also introduces the concept of prior experience (i.e., whether a user has prior experience with an integrated IS or ERP system) as a moderating variable to examine the impact of perceived benefit and attitude toward change in user resistance. As such, we propose eight hypotheses with respect to the model. For the empirical validation of the hypotheses, we developed relevant instruments for each research variable based on prior literature and surveyed 95 professional researchers and the administrative staff of the Korea Photonics Technology Institute (KOPTI). We examined the organizational characteristics of KOPTI, the reasons behind their adoption of an ERP system, process changes caused by the introduction of the system, and employees' resistance/attitude toward the system at the time of the introduction. The results of the multiple regression analysis suggest that, among the six variables, perceived benefit, complexity, attitude toward change, and the psychological reactance trait significantly influence user resistance. These results further suggest that top management should manage the psychological states of their employees in order to minimize their resistance to the forced IS, even in the new system pre-adoption context. In addition, the moderating variable-prior experience was found to change the strength of the relationship between attitude toward change and system resistance. That is, the effect of attitude toward change in user resistance was significantly stronger in those with prior experience than those with no prior experience. This result implies that those with prior experience should be identified and provided with some type of attitude training or change management programs to minimize their resistance to the adoption of a system. This study contributes to the IS field by providing practical implications for IS practitioners. This study identifies system resistance stimuli of users, focusing on the pre-adoption context in a forced ERP system environment. We have empirically validated the proposed research model by examining several significant factors affecting user resistance against the adoption of an ERP system. In particular, we find a clear and significant role of the moderating variable, prior ERP usage experience, in the relationship between the affecting factors and user resistance. The results of the study suggest the importance of appropriately managing the factors that affect user resistance in organizations that plan to introduce a new ERP system or integrate legacy systems. Moreover, this study offers to practitioners several specific strategies (in particular, the categorization of users by their prior usage experience) for alleviating the resistant behaviors of users in the process of the ERP adoption before a system becomes available to them. Despite the valuable contributions of this study, there are also some limitations which will be discussed in this paper to make the study more complete and consistent.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.6C
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• pp.793-800
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• 2004

In this paper, we propose a new automatic pipe grading algorithm for an efficient management of transmission pipe under the ground. Since the conventional transmission pipe evaluation was conducted by subjective decision made by an individual operator, it was difficult to grade them by means of numerical methods and also hard to realistically construct numerical database system. To solve these problems, we Int obtain some information on the current condition of pipes' sections by shooting laser beam at a regular rate and then apply grading algorithm after complete calculation of minimum diameter of pipe. We use some of preprocessing techniques to reduce noise and also use various color models to consider special conditions of each inner pipe. The measurement of pipes' minimum diameter and decision of grade are performed through a detailed processing stages. By some experimental results performed in the field, we show that over 90 percent of correct grade decisions are made by the proposed algorithm.

• Journal of Internet Computing and Services
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• v.6 no.6
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• pp.107-115
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• 2005

A workflow procedure has recently become more complicated and large scaled. In this paper, we propose an advanced workflow modeling methodology, called a fragment driven cooperative workflow modeling methodology. which enables several real workflow designers to cooperatively define a workflow model. The methodology is a Bottom-Up approach in terms of integrating a set of fragment ICNs to compose a complete workflow model. Each fragment ICN is defined by each participant in the cooperative modeling session, We also use the ICN based formal description and the ICN based graphical notation as well. Finally, we prove the feasibility of the methodology by implementing a cooperative workflow modeling system.

• Journal of KIISE:Software and Applications
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• v.33 no.1
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• pp.44-57
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• 2006

With the rapid growth of network technology, two or more products from different vendors are integrated and interact with each other to perform a certain function in the latest systems. Thus. interoperability testing is considered as an essential aspect of correctness of integrated systems. Interoperability testing is to test the ability of software and hardware on different machines from different vendors to share data. Most of the researches model communication system behavior using EFSM(Extended Finite State Machines) and use EFSM as an input of test scenario generation algorithm. Actually, there are many studies on systematic and optimal test case generation algorithms using EFSM. But in these researches, the study for generating EFSM model which is a foundation of test scenario generation isn't sufficient. This study proposes an EFSM generating technique from informal requirement analysis document for more complete interoperability testing. and implements prototype of Test Case Generation Tool generating test cases semi-automatically. Also we describe theoretical base and algorithms applied to prototype implementation.

• International Journal of Highway Engineering
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• v.19 no.4
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• pp.61-68
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• 2017

PURPOSES : A complete signal system is not always the best solution for improving traffic operation efficiency at intersections. An alternative solution is to use a Protected Permitted Left Turn (PPLT) operation method. However, the PPLT method needs to be developed after a detailed study of driving tendencies, most notably the gap acceptance behavior, for successful implementation. In this study, the gap acceptance behavior was investigated under various variables and weather conditions, especially under rain, and the results were compared to the case of normal weather. The results of this study will be helpful in introducing the PPLT method, and are important considering the tendency of attempting unprotected left turns that is extremely common in Korean drivers. METHODS : Data was obtained by analyzing traffic footage at four intersections on a day when the precipitation was greater than 5 mm/h. The collected data was classified into seven variables for statistical analysis. Finally, we used logistic regression analysis to develop a probability distribution model. RESULTS : Gap, traffic volume, and the number of conflicting lanes were factors affecting the gap acceptance behavior of unprotected left turns under rainy conditions. CONCLUSIONS : The probability of attempting unprotected left turns is higher for larger gaps. On the other hand, the probability of attempting unprotected left turns decreases with an increase in the traffic volume. Finally, an increase in the number of conflict lanes leads to a decrease in the probability of attempting unprotected left turns.

• Membrane Journal
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• v.11 no.1
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• pp.14-21
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• 2001

Rapid backpulsing to reduce membrane fouling of hollow fiber ultrafiltration module (polyacrylonitrile with 50000 l'vlWCO, 1.4 rom OD and 0,9 mm ID) was studied with latex solutions. Values estimated by a theoretical model were compared with the ones obtained from the systems with or without backpulsing, Specific Cake resistance, time consUmt for cake growth, diffusion coefficient, and the rate constants of fnur fouling models; the complete, intermediate. standard blocking and cake filtration were calculated to obtain the theoretical values. High frequency backpulsing gave net increase of fluxes by 40~120%. Fluxes predicted by the model were in good agreement with experimental ones within 14% error bound, The optimum backpulsing strength was acquired at 20% in the ranges of 20~40% strength and the optimum frequcncv was acquired at 2 Hz in the ranges of 0.67~3 Hz.