• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.34 no.6
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• pp.609-618
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• 2016

Since demand for location-based services increases and the relevant service becomes more diverse, the use of POI (Point of Interest) is being required in various fields. Various roles of POI for display, search and inquiry exist, but the implementation and expression of such roles are partially limited. Therefore, the data model for implementation is suggested in this paper to enable practical implementation, expression and inquiry of POI data. The data model was developed based on 3 roles of POI including search, expression and linkage, and especially, the spatial relationship between POI objects which was not suggested in previous data models is considered and time series scheme is suggested to enable various expressions and inquiries in application services.

• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.2
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• pp.133-144
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• 1996

To get accurate results, the realistic stress-strain relationships of soils are dependent on a number of factors such as soil types, density, stress levels and stress path. Such attempts are continuously being made by the developement of analytical models for soils incorporating all such factors. Isotropic compression-expansion test and a series of drained conventional triaxial tests with several stress path for Baekma river sand were performed to investigate parameters characteristics of Lade's single work hardening model dependant on the stress path. Using the computer program based on the regression analysis, the values of parameters for the model were determined. In conclusion, the parameters of Lade's model are little influenced by the stress paths. Though yield criterion parameters ( h, ${\alpha}$a) are much influenced by stress level and stress path, the parameters don't have influence on stress-strain behavior.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.3
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• pp.107-118
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• 1998

Two-phase neuro-system identification method is presented. The 1$^{st}$-phase identification uses conventional neural network mapping for modeling an input-output system. The 2$^{nd}$ -phase modeling is also performed sequentially using the 1$^{st}$-phase modeling errors. In the 2$^{nd}$ a phase modeling, newly generated input signals, which are obtained by summing the 1st-phase modeling error and artificially generated uniform series, are utilized as system's I-O mapping elements. The 1$^{st}$-phase identification is interpreted as a “Real Model” system identification because it uses system's real data(i.e., observations and control inputs) while the 2$^{nd}$ -phase identification as a “Artificial Model” identification because of using artificial data. Experimental results are given to verify that the two-phase neuro-system identification could reduce the overall modeling errors.rrors.

• Journal of The Korean Society of Agricultural Engineers
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• v.46 no.7
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• pp.23-32
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• 2004

A spatial simulation model for rural and urban sprawl phenomena was developed with GIS and cellular automata techniques. The model finds out built-up areas invading toward rural areas required for development of existing urban area. Probability of land use change for optimizing the development area was determined using a land suitability analysis method interfaced with GIS methods, based on several criteria in terms of geographic and accessibility factors such as slope of land and distance from city center. Weighting values of the criteria were quantified by an analytic hierarchy process method. For model applicability test, the parameters of criteria were calibrated based on the changes in time series land use data of the test city for 1986, 1996, and 2000, which were classified by remote sensing techniques. Simulated and observed areas in land use maps for city shape of 1996 showed good similarities with each other through a morphology verification method. The model enabled us to evaluate the spatial expansion phenomena of cities considering boundary conditions, and also to simulate land use planning for rural areas in urban fringe.

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.563-565
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• 1998

In this paper, we are proposed optimization method of fuzzy model in order to complex and nonlinear system. In the fuzzy modeling, a premise identification is very important to describe the charateristics of a given unknown system. Then, the proposed fuzzy model implements system structure and parameter identification, using the fuzzy inference method and genetic algorithms. Inference method for fuzzy model presented in our paper include the simplified inference and linear inference. Time series data for gas furance and sewage treatment process are used to evaluate the performance of the proposed model. Also, the performance index with weighted value is proposed to achieve a balance between the results of performance for the training and testing data.

• International Journal of Reliability and Applications
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• v.15 no.1
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• pp.51-64
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• 2014

This paper develops a warranty cost model for complex systems with imperfect repair within a warranty period by addressing a practical case that the first inter-failure interval is longer than any other inter-failure intervals. The product is in its best condition before the first failure if repair is imperfect. After the imperfect repair, other inter-failure intervals which are explained by renewal processes, are stochastically smaller than the first inter-failure interval. Based on this idea, we suggest the failure-interval-failure-criterion model. In this model, we consider two random variables, X and Y where X represents failure intervals and Y represents failure criterion. We also obtain the distribution of the number of failures and conduct the warranty cost analysis. We investigate different types of warranty cost models, reliabilities and other measures for various systems including series-parallel configurations. Several numerical examples are discussed to demonstrate the applicability of the methodologies derived in the paper.

• Smart Structures and Systems
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• v.1 no.3
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• pp.309-324
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• 2005

This paper presents an efficient and accurate coupled beam model for piezoelectric bimorphs based on improved first-order shear deformation theory (FSDT). The model combines the equivalent single layer approach for the mechanical displacements and a layerwise modeling for the electric potential. General electric field function is proposed to reasonably approximate the through-the-thickness distribution of the applied and induced electric potentials. Layerwise defined shear correction factor (k) accounting for nonlinear shear strain distribution is introduced into both the shear stress resultant and the electric displacement integration. Analytical solutions for free vibrations and forced response under electromechanical loads are obtained for the simply supported piezoelectric bimorphs with series or parallel arrangement, and the numerical results for various length-to-thickness ratios are compared with the exact two-dimensional piezoelasticity solution. Excellent predictions with low error estimates of local and global responses as well as the modal frequencies are observed.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.360-364
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• 2009

To verify the suitability of the Railroad safety requirements analysis, the actions of the function which it follows in a given operation condition are composed of the rule model or the state model. And it test must be possible. The subject of condition transfer in compliance with the transfer condition which is an event of system it will be able to accomplish the operation of system. However, tasks allocated to the actor are the duty which is added in organization. This time, the start of duty task is started in compliance with an external or internal condition. If there are 9 tasks which have one objective, the relationship among the previous and the current internal tasks and next tasks which will given is able to show in logical model. Thus when planning an organization, the integral part of class must include Task, Role and Position. And this time we make a series of outputs of examination of organizing model and examples to meet the capable skill.

• Korean System Dynamics Review
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• v.7 no.1
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• pp.67-90
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• 2006

A series of system dynamics model was developed for forecasting demand and supply of human resource in the electricity industry. To forecast demand of human resource in the electric power industry, BLS (Bureau of Labor Statistics) methodology was used. To forecast supply of human resource in the electric power industry, forecasting on the population of our country and the number of students in the department of electrical engineering were performed. After performing computer simulation with developed system dynamics model, it is discovered that the shortage of human resource in the electric power industry will be 3,000 persons per year from 2006 to 2015, and more than a double of current budget is required to overcome this shortage of human resource.

• Journal of The Korean Society of Agricultural Engineers
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• v.51 no.2
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• pp.43-49
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• 2009

Many researcher uses simulation techniques for understanding the phenomenon and expecting the response. Simulation techniques have many advantages which is less time-consuming, easy to control constraints, and cheaper than experimental study. However Researches usually are not good at programming the model, it's hard to implement simulation model using computer language. They use spreadsheet program like Microsoft $excel^{TM}$ Although a spreadsheet program is good for modeling, it's cumbersome to describe expressions which consist of not variable name but location indicator. This study suggests the program which helps researcher developing model using graphical interface and variable name. For verifying usability, the model which is implemented by developed modeler were compared with by spreadsheet program.