• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.487-490
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• 1999

In this paper we propose an efficient content-based image retrieval method using the color and wavelet based features. The color features are extracted from color histograms of the global image and the wavelet based features are extracted from the invariant moments of the high-pass band image through the spatial-frequency analysis of the wavelet transform. The proposed algorithm, called color and wavelet features based query(CWBQ), is composed of two-step query operations for efficient image retrieval: the coarse level filtering operation and the fine level matching operation. In the first filtering operation, the color histogram feature is used to filter out the dissimilar images quickly from a large image database. The second matching operation applies the wavelet based feature to the retained set of images to retrieve all relevant images successfully. The experimental results show that the proposed algorithm yields more improved retrieval accuracy with computationally efficiency than the previous methods.

• Journal of the Korean Solar Energy Society
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• v.26 no.1
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• pp.49-55
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• 2006

The Multipurpose BIPV System(MBIPVS) was evaluated as an effective passive system through analyzing the thermal performance and the efficiency of PV power generation in the previous papers. To achieve the performance better, the operation method should be determined by considering physical conditions in each occasion. Thus, we cheesed the reference operation methods in each season set by the overview of the meteorological data for last 6 years, In-choen, and compared them with the various alternatives that we had made up with for improving thermal performance. The results from adopting various alternatives on MBIPVS showed that the appropriate operational model would be effective to the energy savings ; we could reduce the total loads 1,051.0[kWh] in summer and 108.9[kWh] in winter.

• Journal of the Korea Society of Computer and Information
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• v.21 no.9
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• pp.149-156
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• 2016

This paper is concerned with education courses operating practices for basic computer literacy training. In this study, we propose an example for students to effectively measure and evaluate the achievement of defined ability in the performance measurement and analysis, learning objectives and learning outcomes set in operation throughout the course. Through research and development use case presents the tools for teaching method and effective and objective measurement of the related subjects. And based on the results, we propose the possibility of utilizing NCS-based course operation and education certification. In this study, the measurement process is based on the association with the objective of the development and operation, and measurement tools, measuring tools for measuring learning outcomes associated with the curriculum design methods for the measurement and evaluation of the case of the operation of the course units of learning outcomes and the method proposed.

• IE interfaces
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• v.12 no.2
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• pp.346-353
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• 1999

In this paper, the optimum drilling operation sequence which results into the minimum overall machining time required to produce a (multi-diameter) hole is identified. The operation sequence is defined as the set of ordered operations used for producing a (multi-diameter) hole. The overall machining time is derived by summing the minimum machining times of each operation assigned to a sequence. The operations represent the drilling actions of certain sizes to produce the related holes. The minimum machining time of each operation is obtained by solving the optimization problem. Finally, this paper will identify the effects of machining constraints on the overall machining times and their relationships to sequence selection.

• Journal of the Korean Society of Safety
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• v.8 no.4
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• pp.133-138
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• 1993

The stable and safe operation of a boiler system is essential for ensuring stability of the chemical processes. A dynamic simulation of a boiler drum was performed to identify the dynamics of the boiler drum. The obtained results represented that the variation of process variables disturb boiler system. So, disturbance rejection with tracking and constraints handing was necessary for stable operation of boiler drum. Among many controller, GPC has been known to show good performance in set point tracking than disturbance. In order to improve disturbance rejection performance measurable disturbance term was Introduced in basic GPC model. The controller which had tracking and disturbance rejection was designed for Improving the stable operation of a boiler system.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.17 no.4
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• pp.55-62
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• 2009

The Prime objectives of this study are to identify and analyze possible solutions and select a solution for the specification and operation plan of the meteorological purpose aircraft in Korea. Infrastructure like meteorological purpose aircraft and aircraft operating systems should be set up and their efficient plan must be established to improve meteorological technic in Korea. As a result of the study, we have found that the turboprop engine powered aircraft is the most suitable to initial model for the meteorological purpose aircraft. It was found that the indirect operation method might be the best solution, also. The results of this study may be useful to make decision for selecting specification and operation of the meteorological purpose aircraft.

• Communications of Mathematical Education
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• v.24 no.2
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• pp.385-413
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• 2010

The purpose of this study is to set appropriate targets for school-year levels and types of mathematical communication. First, I classify mathematical communication into four types as Discourse, Representation, Operation and Complex and refer to them collectively as the 'D.R.O.C pattern'. I have listed achievement factors based on the D.R.O.C pattern hearing opinions from specialists to set a target, then set a final target after a 2nd survey with specialists and teachers. I have set targets for mathematical communication in elementary schools suitable to its status and students' levels in our country. In NCTM(2000), standards of communication were presented only from kindergarten to 12th grade students, and, for four separate grade bands(prekindergarten through grade 2, grades 3-5, grades 6-8, grades 9-12), they presented characteristics of the same age group through analysis of classes where communication was active and the stated roles of teachers were suitable to the characteristics of each school year. In this study, in order to make the findings accessible to teachers in the field, I have classified types into Discourse, Representation, Operation and Complex (D.R.O.C Pattern) according to method of delivery, and presented achievement factors in detail for low, middle and high grades within each type. Though it may be premature to set firm targets and achievement factors for each school year group, we hope to raise the possibility of applying them in the field by presenting targets and achievement factors in detail for mathematical communication.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.59 no.1
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• pp.44-54
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• 2023

In this study, the second-order Nomoto's nonlinear expansion model was implemented as a Tagaki-Sugeno fuzzy model based on the heading angular velocity to design the automatic steering system of a ship considering nonlinear elements. A Tagaki-Sugeno fuzzy PID controller was designed using the applied fuzzy membership functions from the Tagaki-Sugeno fuzzy model. The linear models and fuzzy membership functions of each operating point of a given nonlinear expansion model were simultaneously tuned using a genetic algorithm. It was confirmed that the implemented Tagaki-Sugeno fuzzy model could accurately describe the given nonlinear expansion model through the Zig-Zag experiment. The optimal parameters of the sub-PID controller for each operating point of the Tagaki-Sugeno fuzzy model were searched using a genetic algorithm. The evaluation function for searching the optimal parameters considered the route extension due to course deviation and the resistance component of the ship by steering. By adding a penalty function to the evaluation function, the performance of the automatic steering system of the ship could be evaluated to track the set course without overshooting when changing the course. It was confirmed that the sub-PID controller for each operating point followed the set course to minimize the evaluation function without overshoot when changing the course. The outputs of the tuned sub-PID controllers were combined in a weighted average method using the membership functions of the Tagaki-Sugeno fuzzy model. The proposed Tagaki-Sugeno fuzzy PID controller was applied to the second-order Nomoto's nonlinear expansion model. As a result of examining the transient response characteristics for the set course change, it was confirmed that the set course tracking was satisfactorily performed.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.4
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• pp.395-402
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• 2016

When the operation of battery is converted at charging and discharging system based on a DC micro grid, the voltage is fluctuated. And excessive voltage fluctuation could cause damage or failure of charging and discharging equipment. Therefore, in this paper, we studied the operating schedule of the charging and discharging system based on the DC micro grid and a design point of the capacitor which was able to reduce the voltage fluctuation. A result of computer simulation showed that when a fluctuation-reducing capacitor which had an initial value of 600V/35mF was applied at the charging and discharging system based on a DC micro grid which was operated with three charging battery sets and five discharging battery sets, voltage fluctuation by charging and discharging operation was reduced by about 63.3%. Furthermore, voltage fluctuation which occurred when initial network voltage was stabilized was reduced by about 73%.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.6
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• pp.593-601
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• 2011

An analysis program to simulate the operation of a polymer electrolyte membrane fuel cell (PEMFC) system was set up, and system operation with variations in the working conditions of various components (especially the thermal management system) was simulated. The entire system included a PEMFC stack and balance-of-plant components such as an air-supply unit, a fuel-supply unit, and a heat-management unit (cooling system). Thermodynamic models of all components were made to evaluate the design performance of the entire system, and then off-design models were set up to simulate the operation of the entire system under arbitrary working conditions. A parametric study was carried out to examine the effects of varying the operating conditions (especially the ambient conditions and the operating conditions of the cooling system) on the operation and performance of the entire system.