• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.7
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• pp.688-696
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• 2000

A scheme for fault detection on the subsystem level is presented. The method uses analytical redundancy and consists in generating residuals by comparing each measurement with an estimate computed from the reference models. In this study regression neural network models are used as reference models. The regression neural network is memory-based feed forward network that provides estimates of continuous variables. The simulation result demonstrated that the proposed method can effectively detect faults in an air handling unit(AHU). The results show that the regression models are accurate and reliable estimators of the highly nonlinear and complex AHU.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.6
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• pp.765-771
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• 1998

An artificial neural network(NN) technique is developed for hardware redundant sensor validation. Since the measurement space is a continuous space with many operating regions, it is difficult to train a NN to correctly detect failure in an accurate measurement system. A conventional backpropagation NN is modified to include an additional preprocessing layer that extracts classification features from scalar measurements. This feature extraction means transform the measurement space to parity space. The NN is independent of the state variable being measured, the instrument range, and the signal tolerance. This NN resembles the parity space approach to signal validation, except that analytical parity equations are unneeded and the NN pattern recognition capability is utilized for decision making.

• Journal of Korean Society for Quality Management
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• v.20 no.2
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• pp.94-108
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• 1992

This study involves an experiment for the cognitive experiment design and the human reliability in software engineering. Its overall objectives are to analyze common-cause human domain error and reliability in human-software interaction. A laboratory study was performed to analyze software engineers' task behavior in software production and to identify software design factors contributing to the effects in common cause failure redundancy. Common-cause model and its function were developed, then the main experiment using programming experts was conducted in order to define a new cognitive paradigm, in the aspects of identification, pattern recognition, and behavior domain for human reliability and quality control in software development. The results and analytical procedures developed in this research can be applied to reliability improvement and cost reduction in software development for many applications. Results are also expected to provide guidelines for software engineering quality control and for more effective design of human-software interface system.

• Journal of the Ergonomics Society of Korea
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• v.11 no.2
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• pp.35-45
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• 1992

This study is to define a congitive paradigm including a new model of common cause human behavior error domain and to analyze their causal factors and their properties of common cause human error characteristics in software engineering. A laboratory study was performed to analyze the common causes of human behavior domain error in software development and to identify software design factors contributing to the common cause effects in common cause failure redundancy. The results and analytical paradigm developed in this research can be applied to reliabbility improvement and cost reduction in software development for many applications. Results are also expected to provide training guidelines for software engineers and for more effective design of ultra-high reliable software packages.

• Korean Institute of Interior Design Journal
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• no.8
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• pp.32-38
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• 1996

The main focus of this paper is to apply contemporary aesthetics and psychological study with interior design analysis. Up to now, the methodology of interior design analysis has been developed toward a more qualitative way. By the virtue of the perception , congnition , and information theory, which oriented toward a quantitative approach, it became possible to investigate interior space analysis to a more objective and scientific ways. The purpose of this study is to investigate Modern and Post-Modern interior - architectural style with quantitative analytical method. The subjective interior critique studied by intuitive research will be transferred to scientific way by using quantitative formula . Savoye Villa and Guardiola House were selected as study model, because each architectural works ware regarded as masterpieces of Modern and Post-Modern style. These two oppositional style model will be distinguished with mathematical quantity by calculating Iave , Hmax, and Redundancy formula.

• Proceedings of the ESK Conference
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• 1992.10a
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• pp.84-89
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• 1992

This study is to develop a cognitive paradigm including a new model of common cause human behavior error domain and to analyze their causal factors and their properties of common cause huamn error characteristics in software engineering.l A laboratory study was performed to analyze the common causes of human behavior domain error in software develoment and to indentify software design factors contributing to the common cause effects in common cause failure redundancy. The results and analytical paradigm developed in this resuarch can be applied to reliability improvement and cost reduction in software development for many applications. Results are also expected to provide training guideliness for software engineers and for more effective design of ultra-high reliabile software packages.

• Journal of Ocean Engineering and Technology
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• v.34 no.6
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• pp.454-460
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• 2020

In 2019, the Korean government announced the 3rd Basic Plan for Energy, which included expanding the rate of renewable energy generation by 30-40% by 2040. Hence, offshore wind power generation, which is relatively easy to construct in large areas, should be considered. The East Sea coast of Korea is a sea area where the depth reaches 50 m, which is deeper than the west coast, even though it is only 2.5 km away from the coastline. Therefore, for offshore wind power projects on the East Sea coast, a floating offshore wind power should be considered instead of a fixed one. In this study, a response analysis was performed by applying the analytical conditions of IEC61400-3-2 for the design of floating offshore wind power generation systems. In the newly revised IEC61400-3-2 international standard, design load cases to be considered in floating offshore wind power systems are specified. The upper structure applied to the numerical analysis was a 5-MW-class wind generator developed by the National Renewable Energy Laboratory (NREL), and the marine environment conditions required for the analysis were based on the Ulsan Meteorological Buoy data from the Korea Meteorological Administration. The FAST v8 developed by NREL was used in the coupled analysis. From the simulation, the maximum response of the six degrees-of-freedom motion and the maximum load response of the joint part were compared. Additionally, redundancy was verified under abnormal conditions. The results indicate that the platform has a maximum displacement radius of approximately 40 m under an extreme sea state, and when one mooring line is broken, this distance increased to approximately 565 m. In conclusion, redundancy should be verified to determine the design of floating offshore wind farms or the arrangement of mooring systems.

• Journal of Korea Multimedia Society
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• v.9 no.11
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• pp.1395-1409
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• 2006

A spatial data warehouse has spatial data cube composed of multi-dimensional data for efficient OLAP(On-Line Analytical Processing) operations. A spatial data cube supporting concept hierarchies holds huge amount of data so that many researches have studied a incremental update method for minimum modification of a spatial data cube. The Cube, however, compressed by eliminating prefix and suffix redundancy has coalescing paths that cause update inconsistencies for some updates can affect the aggregate value of coalesced cell that has no relationship with the update. In this paper, we propose incremental batch update method of a spatial data cube. The proposed method uses duplicated nodes and extended node structure to avoid update inconsistencies. If any collision is detected during update procedure, the shared node is duplicated and the duplicate is updated. As a result, compressed spatial data cube that includes concept hierarchies can be updated incrementally with no inconsistency. In performance evaluation, we show the proposed method is more efficient than other naive update methods.

• International Journal of Control, Automation, and Systems
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• v.5 no.4
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• pp.410-418
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• 2007

For the purpose of fault detection of the primary control surface, real-time estimation of the longitudinal stability and control derivatives of the DURUMI-II using the flight data is considered in this paper. The DURUM-II, a research UAV developed by KARI, is designed to have split control surfaces for the redundancy and to guarantee safety during the fault mode flight test. For fault mode analysis, the right elevator was deliberately fixed to the specified deflection condition. This study also mentions how to implement the multi-step control input efficiently, and how to switch between the normal mode and the fault mode during the flight test. As a realtime parameter estimation technique, Fourier transform regression method was used and the estimated data was compared with the results of the analytical method and the other available method. The aerodynamic derivatives estimated from the normal mode flight data and the fault mode data are compared and the possibility to detect the elevator fault by monitoring the control derivative estimated in real time by the computer onboard was discussed.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.1
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• pp.1-7
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• 2012

The brake-by-wire technology is a new automotive chassis system that allows standard braking operations by electronic components with lighter weights and faster response. The brake-by-wire units such as EMB (Electro-Mechanical Brake) are controlled by electronic sensors and actuators and, thus, the fault diagnosis is essential for implementation. In this study, a model-based fault diagnosis system is developed for the sensors based on the analytical redundancy method. The fault detection algorithm is verified in simulations for various faulty cases. A test bench is built including the EMB unit and the performance of the proposed fault diagnosis system is evaluated through the experiment.