• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.430-436
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• 2018

Special railway vehicles for track maintenance are equipped with a tamping device that adjusts various track trajectories to reduce the vibration of rolling stock and improve ride quality during trains passing over a track. The development of a simulator that can confirm the error of the actual tamping work is important for reducing human error in the linearization of the track misalignment. In this study, to improve the reality and training effect of conventional 2D simulator, 3D simulator modeling was implemented for tamping work of special railway vehicles in virtual space. The problem of buffering during high screen quality of tamping work was solved using the Unwrap UVW mapping technique of a low polygon extracted from high quality polygon modeling. The human error in the training of the tamping work was detected by the principle of circle and square collision when the tamping tyne and the sleeper collided. In addition, vibration of the driving chair was generated at the same time as the collision, and the number of the sleeper strikes is displayed on the simulator exercise screen. Owing to the scattering of railway ballast protruding from the sleepers, which had a serious effect on the safety of the vehicle, the gravel bouncing effect of the tamping unit was applied.

• Geophysics and Geophysical Exploration
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• v.17 no.2
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• pp.49-57
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• 2014

3D magnetic inversion, based on the assemblage of 2D forward modeling and inversion as a practical technique to reflect the a priori information, was conducted to investigate the spatial distribution features of black-shale related and pyrometamorphic uranium deposit and several lithological units of Ogcheon Super Group in an area of Geumsan. By using the 3D visualization technique with suitable susceptibility interval and horizontal slice map, the spatial distribution of magnetic susceptibility corresponded to the black shale related uranium bearing lithological units, Black Slate member was well coincided with a information of uranium deposit. Also, even though it is indirect indicator for the detetction of uranium deposits interbedded in Gray Hornfels member, spatial susceptibility distribution which shows the south-east magnetic linearment corresponding to the Majeon-ri formation and Dark Gray Slate were matched well. From this investigation, we inferred that maximum depth extension which Black Slate member can be separately recognized with respect to adjacent Dark Gray Slate with strong magnetic susceptibility anomaly is about 150m with reference elevation level of 306m. In addition, Majeon-ri formation located south of Black Slate member revels relatively high magnetic susceptibility range but shows high spatial susceptibility fluctation. And, as an intrusive rocks, Jurassic Biotite Granite shows relatively low magnetic susceptibility characteristics. On the contrary, Cretaceous granite distributed in soutthern part of the study area shows the relatively high susceptibility distribution.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.5
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• pp.22-33
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• 2021

In the case of open phase faults caused by the disconnection of distribution feeders interconnected to a PV system, many problems can occur depending on the core type and wiring method of the grid-connected transformers. Moreover, open phase faults are difficult to detect because the open phase voltage of the existing protection relay (Open Phase Relay (47)) can be maintained, even though a disconnection fault occurred, depending on the wiring method and the iron core type of the grid-connected transformer for a PV system. Therefore, this paper proposes a novel algorithm to detect open phase faults by comparing the currents and phases between the primary and secondary sides of a grid-connected transformer. In addition, this paper presents the modeling of a distribution system and protection devices for detecting open phase faults using PSCAD/EMTDC S/W, and implements a test protection device for detecting open phase faults based on the above-mentioned modeling. The simulation and test results confirmed that the proposed algorithm is useful for detecting open phase faults according to the wiring method and iron core type of grid-connected transformer for a PV system because operation slope and unbalance rate of the primary current exceed the setting value (30[%]) of the protection device.

• Journal of Intelligence and Information Systems
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• v.21 no.1
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• pp.99-118
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• 2015

Object-oriented programming languages have been widely selected for developing modern information systems. The use of concepts relating to object-oriented (OO, in short) programming has reduced efforts of reusing pre-existing codes, and the OO concepts have been proved to be a useful in interpreting system requirements. In line with this, we have witnessed that a modern conceptual modeling approach supports features of object-oriented programming. Unified Modeling Language or UML becomes one of de-facto standards for information system designers since the language provides a set of visual diagrams, comprehensive frameworks and flexible expressions. In a modeling process, UML users need to consider relationships between classes. Based on an explicit and clear representation of classes, the conceptual model from UML garners necessarily attributes and methods for guiding software engineers. Especially, identifying an association between a class of part and a class of whole is included in the standard grammar of UML. The representation of part-whole relationship is natural in a real world domain since many physical objects are perceived as part-whole relationship. In addition, even abstract concepts such as roles are easily identified by part-whole perception. It seems that a representation of part-whole in UML is reasonable and useful. However, it should be admitted that the use of UML is limited due to the lack of practical guidelines on how to identify a part-whole relationship and how to classify it into an aggregate- or a composite-association. Research efforts on developing the procedure knowledge is meaningful and timely in that misleading perception to part-whole relationship is hard to be filtered out in an initial conceptual modeling thus resulting in deterioration of system usability. The current method on identifying and classifying part-whole relationships is mainly counting on linguistic expression. This simple approach is rooted in the idea that a phrase of representing has-a constructs a par-whole perception between objects. If the relationship is strong, the association is classified as a composite association of part-whole relationship. In other cases, the relationship is an aggregate association. Admittedly, linguistic expressions contain clues for part-whole relationships; therefore, the approach is reasonable and cost-effective in general. Nevertheless, it does not cover concerns on accuracy and theoretical legitimacy. Research efforts on developing guidelines for part-whole identification and classification has not been accumulated sufficient achievements to solve this issue. The purpose of this study is to provide step-by-step guidelines for identifying and classifying part-whole relationships in the context of UML use. Based on the theoretical work on Meta-model Formalization, self-check forms that help conceptual modelers work on part-whole classes are developed. To evaluate the performance of suggested idea, an experiment approach was adopted. The findings show that UML users obtain better results with the guidelines based on Meta-model Formalization compared to a natural language classification scheme conventionally recommended by UML theorists. This study contributed to the stream of research effort about part-whole relationships by extending applicability of Meta-model Formalization. Compared to traditional approaches that target to establish criterion for evaluating a result of conceptual modeling, this study expands the scope to a process of modeling. Traditional theories on evaluation of part-whole relationship in the context of conceptual modeling aim to rule out incomplete or wrong representations. It is posed that qualification is still important; but, the lack of consideration on providing a practical alternative may reduce appropriateness of posterior inspection for modelers who want to reduce errors or misperceptions about part-whole identification and classification. The findings of this study can be further developed by introducing more comprehensive variables and real-world settings. In addition, it is highly recommended to replicate and extend the suggested idea of utilizing Meta-model formalization by creating different alternative forms of guidelines including plugins for integrated development environments.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.6
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• pp.591-599
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• 2011

This study investigates influencing factors on numerical crash simulation between RC slab and soft projectile using explicit dynamic method. Considered experimental test is the MEPPEN II/4 test, which has been conducted at the end of the years 70' in Germany as one of the numerous experimental test related to design of nuclear power plants. LS-DYNA software is adopted for numerical study, and influencing factors such as constitutive model of concrete, strain rate effect of steel and concrete, support modeling method, etc. are investigated. More reasonable simulation results can be achieved through appropriate consideration of these factors, especially of constitutive model of concrete material since this factor affects most among the investigated factors.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.5
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• pp.147-154
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• 2015

In this paper, we employed a model which defines the sensitivity according to the background luminance, so called JND (Just Noticeable Difference), and applied to the video coding. The proposed method finds out the maximum possible quantization parameter for the current unit based on the threshold of JND model and reduce the bitrate with similar perceptual quality. It selects the higher quantization parameter and reduce the bitrate when the reconstructed signal which is coded with higher quantization parameter is in a range of allowance based on the JND threshold, i.e. the signal has the similar perceptual quality compared to that is coded with the initial quantization parameter. The proposed algorithm was implemented on HM16.0, which is a reference software of the latest video coding standard HEVC (High Efficiency Video Coding) and the coding performance was evaluated. Compared to HM16.0, the proposed algorithm achieved maximum 20.21% and 6.18% of average bitrate reduction with the similar perceptual quality.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.9
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• pp.1785-1790
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• 2016

There is exhibit a degree of pain in the occurrence and course of treatment levels or oral, pain rating scale actions, such as illness, for example, the discomfort scale because of the pain "annoying", "unpleasant" "annoyed am", "painful" represents a pain scale of the order of "painful", "hard to bear", "very difficult to bear". Depression is recognized based on the premise of the situation, because it is difficult to recognize themselves. In this paper we define the components of the depression can be seen lifestyle which can lead to depression or through a biological signal. The depression index was derived from the ontology modeling to understand the state of depression. Depression ontology components and depression index will be aware of the situation based information services for depression. Combined with the situational awareness based devices and can be synchronized to verify the results of the depression index. It will be applied to improve lifestyle factors that of depression.

• Archives of design research
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• v.13 no.3
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• pp.29-38
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• 2000

Human has been living in the relation with diverse artifacts ranging from simple tools to complex systems. The relation is an interaction between user and product with input and output process to achieve a certain goals. Natural inter-connection is very important to this interaction. The visualized operation and the dear feedback of product play a critical role in making input and output distinct at both sides. So product innovation means removing mental and physical loads between product and user based on understanding and analyzing interaction. This study proposes the interaction grid as a framework to visualize the interaction. The interaction grid is the format to describe the input and output process between user and product. Modeling and analysis of interaction is based on the interaction grid. Finally, this study discusses the idea exploration method for product innovation with interaction grid, and develops prototype of interaction analysis system for supporting idea exploration.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.6C
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• pp.561-570
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• 2009

Ultra-wideband communication systems based on impulse radio have merits that are possible for the high data rate transmission, high resolution ranging are positioning system. Conventionally, in order to accomplish these features, the high-speed ADC (Analog to Digital Convertor) is necessary to apply radio determination system operating in time domain. However, considering low rate - wireless personal area network (LR-WPAN) aims to low-cost hardware implementation, the expensive ADC converting GHz sampling per second is not appropriate. So, this paper introduces a low complex AR (Auto Regressive) model based non-coherent ranging scheme operating in frequency domain with using low-speed ADC utilizing analog Voltage Control Oscillator (VCO) mode for the frequency domain transformation. To verify the superiority of the proposed ranging and location algorithm working in frequency domain, the suggested IEEE 802.15.4a TG channel model is used to exploit affirmative features of the proposed algorithm with conducting the simulation results.

• Journal of the Korea Convergence Society
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• v.6 no.3
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• pp.127-134
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• 2015

In this paper, we design a semantic-based syllabus template including learning ontologies. A syllabus has been considered as a important blueprint of teaching in universities. However, the current syllabus has no importance in real world because most of all syllabus management systems provide simple functionalities such as, creation, modification, and retrieval. In this paper, our approach consists of definition of hierarchical structure of syllabus and semantic relationships of syllabuses, formalization of learning goals, learning activity, and learning evaluation using Bloom's taxonomy and design of learning subject ontologies for improving the usability of syllabus. We prove the correctness of our proposed methods according to implementing a real syllabus for JAVA programing course and experiments for retrieving syllabuses.