• The Journal of Information Systems
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• v.16 no.4
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• pp.131-155
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• 2007

The purpose of this thesis is to study on the philosophical analysis model and its methodological application of information systems research evaluation from critical realist perspective. Fist of all, I examine ontological epistemological methodological assertions of critical realism. Because the philosophy of critical realism is an opportunity for information systems study. I examine Dobson and Mutch's critical realist perspective on actors-structure model. I suggest a critical realist actors-praxis-structure model. This model provides the potential for a new approach to social investigations in its provision of an ontology for the analytical separation of structure and agency. Of most importance might be the incorporation of non-humans into the analysis of social interaction and of technology into the elaboration of structures. I also examine Tsoukas's critical realistic meta-theory of management. I suggest a critical realist IS management model. This model elucidate the nature of management and delineate the scope of applicability of various perspectives on management. The causal powers of management reside in the real domain and, taken together, their logics are contradictory, the effects of their contradictory composition are contingent upon prevailing contingencies. I analyze Carlsson's theory of design knowledge. His framework builds on that the aim of IS design science research is to develop practical knowledge for the design and realization of different classes of IS initiatives, where IS are viewed as socio-technical systems and not just IT artefacts. The framework proposes that the output of IS design science research is practical IS design knowledge in the form of field-tested and grounded technological rules. The IS design knowledge is developed through an IS design science research cycle. In conclusion, I think that IS actors-praxis-structure model, meta-theoretical IS management model, and IS design knowledge model according to critical realistic approach are very useful for IS research evaluation. Nevertheless, important problems are left not resolved.

• Coupled systems mechanics
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• v.6 no.3
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• pp.251-272
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• 2017

In this paper, the thermo-mechanical vibration characteristics of functionally graded (FG) nanobeams subjected to three types of thermal loading including uniform, linear and non-linear temperature change are investigated in the framework of third-order shear deformation beam theory which captures both the microstructural and shear deformation effects without the need for any shear correction factors. Material properties of FG nanobeam are assumed to be temperature-dependent and vary gradually along the thickness according to the power-law form. Hence, applying a third-order shear deformation beam theory (TSDBT) with more rigorous kinetics of displacements to anticipate the behaviors of FG nanobeams is more appropriate than using other theories. The small scale effect is taken into consideration based on nonlocal elasticity theory of Eringen. The nonlocal equations of motion are derived through Hamilton's principle and they are solved applying analytical solution. The obtained results are compared with those predicted by the nonlocal Euler-Bernoulli beam theory and nonlocal Timoshenko beam theory and it is revealed that the proposed modeling can accurately predict the vibration responses of FG nanobeams. The obtained results are presented for the thermo-mechanical vibration analysis of the FG nanobeams such as the effects of material graduation, nonlocal parameter, mode number, slenderness ratio and thermal loading in detail. The present study is associated to aerospace, mechanical and nuclear engineering structures which are under thermal loads.

• Structural Engineering and Mechanics
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• v.89 no.2
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• pp.199-211
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• 2024

The loading capacity of engineering structures/components reduces after the initiation and propagation of crack eventually leads to the final failure. Hence, it becomes essential to deal with the crack and its effects at the design and simulation stages itself, by detecting the prone area of the fracture. The phase-field (PF) method has been accepted widely in simulating fracture problems in complex geometries. However, most of the PF methods are formulated with second order continuity theoryinvolving C⁰ continuity. In the present study, PF method based on fourth-order (i.e., higher order) theory, maintaining C¹ continuity has been proposed for ductile fracture simulation. The formulation includes fourth-order derivative terms of phase field variable, varying between 0 and 1. Applications of fourth-order PF theory to ductile fracture simulation resulted in novelty in this area. The proposed formulation is numerically solved using a two-dimensional finite element (FE) framework in 3-layered manner system. The solutions thus obtained from the proposed fourth order theory for different benchmark problems portray the improvement in the accuracy of the numerical results and are well matched with experimental results available in the literature. These results are also compared with second-order PF theory and a comparison study demonstrated the robustness of the proposed model in capturing ductile behaviour close to experimental observations.

• Proceedings of the KSPS conference
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• 1996.02a
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• pp.41-46
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• 1996

Within the framework of prosodic phonology (or the theory of phonology-syntax connection), the rhythm unit is not regarded as a domain of phonological rules. But I argue in this paper that the rhythm unit functions as a domain of phonological rules in Korean. I discuss five phonological rules whose domain of application is the rhythm unit.

• Journal of the Korean Ceramic Society
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• v.14 no.4
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• pp.242-247
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• 1977

By means of coloring of plane nets a number of different tetrahedral frameworks can be derived. With the aid of this method all tetrahedral framework structures which built up of layer structures with 2, 4, 8 tetrahedra per unit cell and 6-membered ring or 4-8-membered ring are given. For the systematic derivation of all possible structures, graph theory may be introduced.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.4
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• pp.1197-1208
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• 2014

The problem of the oblique water entry of a three dimensional body is considered. Wagner theory is the theoretical framework. Applications are discussed for an elliptic paraboloid entering an initially flat free surface. A dedicated experimental campaign yields a data base for comparisons. In the present analysis, pressure, force and dynamics of the wetted surface expansion are assessed.

• East Asian mathematical journal
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• v.16 no.2
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• pp.267-275
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• 2000

In this paper, we study the duality theory of nonlinear parabolic systems. The main objective is to prove the duality theorem under general conditions within an infinite-dimensional framework. As an application, an example is given.

• Korean Journal of Social Welfare
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• v.65 no.2
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• pp.103-130
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• 2013

Although both ecosystem theory and empowerment have become the most prevalent candidate for integrated paradigm for social welfare practices, they could not overcome completely the long-standing and sharp divides between micro and macro practices, that is, between subject and structure as a main explanatory element in social welfare realm. Along with such traditional dualism and tension, a new emerging divide between modernism and postmodernism regarding intrinsic mission and roles of social welfare has urged strongly to develop the overarching theoretical framework for social welfare practice. In this regard, this study aims to recast the ecosystem theory and empowerment through the reflexive modernization theory of critical sociologist Anthony Giddens. With relatively strong emphasis on human capability coined as the reflexivity, Giddens's own creative theory of modernization can be thoroughly expected to provide a solid foundation of integrated paradigm enough to bridge the existing dualisms in social welfare theory and practice. Especially, his unique account of integrated way of how human agency is involved in the construction of social structure and how to transform each other recursively has profound implication for empowerment to be adequate and proper comprehensive framework for social welfare practice.

• Journal of the Korean Operations Research and Management Science Society
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• v.38 no.2
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• pp.75-93
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• 2013

In applying Markowitz's portfolio selection model to the stock market, we developed a comprehensive investment decision-making framework including key inputs for portfolio theory (i.e., individual stocks' expected rate of return and covariance) and minimum required expected return. For estimating the key inputs of our decision-making framework, we utilized an exponentially weighted moving average (EWMA) which places more emphasis on recent data than the conventional simple moving average (SMA). We empirically analyzed the investment results of the decision-making framework with the same 15 stocks in Samsung Group Funds found in the Korean stock market between 2007 and 2011. This five-year investment horizon is marked by global financial crises including the U.S. subprime mortgage crisis, the collapse of Lehman Brothers, and the European sovereign-debt crisis. We measure portfolio performance in terms of rate of return, standard deviation of returns, and Sharpe ratio. Results are compared with the following benchmarks : 1) KOSPI, 2) Samsung Group Funds, 3) Talmudic portfolio based on the na$\ddot{i}$ve 1/N rule, and 4) Markowitz's model with SMA. We performed sensitivity analyses on all the input parameters that are necessary for designing an investment decision-making framework : smoothing constant for EWMA, minimum required expected return for the portfolio, and portfolio rebalancing period. In conclusion, appropriate use of the comprehensive investment decision-making framework based on the Markowitz's model integrated with EWMA proves to achieve outstanding performance compared to the benchmarks.

• ETRI Journal
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• v.39 no.2
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• pp.222-233
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• 2017

Debugging in distributed environments, such as wireless sensor networks (WSNs), which consist of sensor nodes with limited resources, is an iterative and occasionally laborious process for programmers. In sensor networks, it is not easy to find unintended bugs that arise during development and deployment, and that are due to a lack of visibility into the nodes and a dearth of effective debugging tools. Most sensor network debugging tools are not provided with effective facilities such as real-time tracing, remote debugging, or a GUI environment. In this paper, we present a hybrid debugging framework (HDF) that works on WSNs. This framework supports query-based monitoring and real-time tracing on sensor nodes. The monitoring supports commands to manage/control the deployed nodes, and provides new debug commands. To do so, we devised a debugging device called a Docking Debug-Box (D2-Box), and two program agents. In addition, we provide a scalable node monitor to enable all deployed nodes for viewing. To transmit and collect their data or information reliably, all nodes are connected using a scalable node monitor applied through the Internet. Therefore, the suggested framework in theory does not increase the network traffic for debugging on WSNs, and the traffic complexity is nearly O(1).