• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.490-493
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• 2004

In the analysis of early-age concrete behavior, the fresh concrete is considered as a structural element immediately after mixing. But for the activation of real structural behavior in the fresh concrete, the so-called setting time is necessary a few hours after the beginning of hydration reaction. In this paper, analysis on the setting behavior is carried out by proposing an analytical model based on the percolation theory as well as the expanding cluster model by defining the setting as a microstructure formation in fresh concrete. An experimental investigation is also carried out to show the influences of curing temperature, mineral admixtures and chemical admixture on setting behavior of fresh concrete. Finally, the analytical results using proposed model are compared with the experimental results for the sake of verification.

• Journal of Korean Institute of Industrial Engineers
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• v.17 no.1
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• pp.51-58
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• 1991

This paper presents a single-echelon, single item, stochastic lead time and static demand inventory model for situations in which, during the stockout period, a fraction ${\beta}$ of the demand is backordered and the remaining fraction $(1-{\beta})$ is lost. In this situations, an objective function representing the average annual cost of inventory system is obtained by defining a time-proportional backorder cost and a fixed penalty cost per unit lost. The optimal operating policy variables minimizing the average annual cost are calculated iteratively. At the extremet ${\beta}=1$, the model presented reduces to the usual backorder case. A numerical example is solved to illustrate the algorithm developed.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1510-1515
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• 2005

This paper is concerned with a Logic-based Fuzzy Neural Networks (LFNN) with the aid of fuzzy granulation. As the underlying design tool guiding the development of the proposed LFNN, we concentrate on the context-based fuzzy clustering which builds information granules in the form of linguistic contexts as well as OR fuzzy neuron which is logic-driven processing unit realizing the composition operations of T-norm and S-norm. The design process comprises several main phases such as (a) defining context fuzzy sets in the output space, (b) completing context-based fuzzy clustering in each context, (c) aggregating OR fuzzy neuron into linguistic models, and (c) optimizing connections linking information granules and fuzzy neurons in the input and output spaces. The experimental examples are tested through two-dimensional nonlinear function. The obtained results reveal that the proposed model yields better performance in comparison with conventional linguistic model and other approaches.

• Journal of Industrial Technology
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• v.24 no.A
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• pp.47-57
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• 2004

Industrial efforts for increased market sales have directed towards the development and implementation of on-line marketing systems under recent e-business environment. Internet-based shopping mall is one of the most popular system. A business process model for an intermediary type shopping mall using IDEF0 has been presented in this study. Specific efforts have been focused on defining and analyzing a diversity of business processes embedded in practical B2B and B2C mall system operations. We first briefly examined the considered system with IDEF0 design. We then defined fundamental business processes within shopping mall systems. Upon careful examination and analysis of them, a detailed business process model based on IDEF methodology has been designed. The results in this study may well form a conceptual framework for shopping mall development and operations.

• Steel and Composite Structures
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• v.6 no.2
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• pp.123-138
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• 2006

This paper proposes a model for the analysis of the construction sequences of steel-concrete composite decks in which the slab is cast-in-situ for segments. The model accounts for early age shrinkage, such as thermal and endogenous shrinkage, drying shrinkage, tensile creep effects and the complex sequences of loading due to pouring of the different slab segments. The evolution of the structure is caught by suitably defining the constitutive relationships of the concrete and the steel reinforcements. The numerical solution is obtained by means of a step-by-step procedure and the finite element method. The proposed model is then applied to a composite deck in order to show its potential.

• Journal of the Korean Society for Nondestructive Testing
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• v.26 no.3
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• pp.198-205
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• 2006

The necessity of nondestructively inspecting austenitic steels, fiber-reinforced composites, and other inherently anisotropic materials has stimulated considerable interest in developing beam models for anisotropic media. The properties of slowness surface playa key role in the beam models based on the paraxial approximation. In this paper, we apply a modular multi-Gaussian beam (MMGB) model to study the effects of material anisotropy on ultrasonic beam profile. It is shown that the anisotropic effects of beam skew and excess beam divergence enter into the MMGB model through parameters defining the slope and curvature of the slowness surface. The overall beam profile is found when the quasilongitudinal(qL) beam propagates in the symmetry plane of transversely isotropic austenitic steels. Simulation results are presented to illustrate the effects of these parameters on ultrasonic beam diffraction and beam skew. The MMGB calculations are also checked by comparing the anisotropy factor and beam skew angle with other analytical solutions.

• Journal of Korea Multimedia Society
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• v.18 no.7
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• pp.873-885
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• 2015

Today, It is difficult to search the various and numerous information efficiently. For this reason, Semantic Web emerged to provide searching services more easily through the structuring of a variety of unstructured format data and the definition of meaningful relationships between information. Especially, definition of relationship and meaning among resources is significant to share and infer related information. Ontology modeling plays just that role. Weapon parts development information is unstructured and dispersed all over. There are many difficulties in finding desired information, leading to getting improper outcomes. In this paper, we present an intuitive ontology model with weapon parts development information including the multi-dimensional information analysis and expansion of the relevant information. This study build up a ontology model through creating class and hierarchy about parts information and defining the properties of classes with Ontology Development 101[1] procedures using Protégé tools. The ontology model provides users with a platform on which search of needed information can be easy and efficient.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.311-311
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• 2000

We propose a DP-based formulation for matching line patterns by defining a robust and stable geometric representation that is based on the conceptual organizations. Usually, the endpoint proximity and collinearity of image lines, as two main conceptual organization groups, are useful cues to match the model shape in the scene. As the endpoint proximity, we detect junctions from image lines. We then search for junction groups by using geometric constraint between the junctions. A junction chain similar to the model chain is searched in the scene, based on a local comparison. A Dynamic Programming-based search algorithm reduces the time complexity for the search of the model chain in the scene. Our system can find a reasonable matching, although there exist severely distorted objects in the scene. We demonstrate the feasibility of the DP-based matching method using both synthetic and real images.

• Water Engineering Research
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• v.1 no.3
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• pp.199-208
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• 2000

The relationship between areal total phosphorus(TP) and areal hydraulic loading was identified and used as defining the trophic state of the reservoir. And three simple, conceptual TP models were tested against the measured in-reservoir TP concentration. The analyses were based on water quality data measured in the Ki Heung reservoir for two years. The results showed that Ki Heung reservoir has undergone eutrophic state, and Dillon's and Vollenweider's TP models were in close agreement with the measured annual mean TP concentration. However, the OECD's model understimated the measured annual mean TP concentration in the Ki Heung reservor. A discussion is given for the hypothetical application of TP loading plot which might be useful for establishing the TP control program in the resavoirs/lakes.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1499-1504
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• 2008

This study shows risk-based evaluation results of casualty accidents for passengers, railway staffs and MOP(Member of public) on the national railway in South Korea. To evaluate risk of these accidents, the hazardous events and the hazardous factors were identified by the review of the accident history and engineering interpretation of the accident behavior. A probability evaluation model for each hazardous event which was based on the accident appearance scenario was developed by using the Fault Tree Analysis (FTA) technique. The probability for each hazardous event was evaluated from the historical data and structured expert judgment. In addition, the severity assessment model utilized by the Event Tree Analysis (ETA) technique was composed of the accident progress scenarios. And the severity for the hazardous events was estimated using fatalities and weighted injuries. The risk assessment model developed can be effectively utilized in defining the risk reduction measures in connection with the option analysis.