• 한국CDE학회논문집
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• 제11권3호
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• pp.157-163
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• 2006

Surfaces of many engineering structures, especially, those of ships are commonly made out of either single- or double-curved surfaces to meet functional requirements. The first step in the fabrication process of a three-dimensional design surface is unfolding or flattening the surface, otherwise known as planar development, so that manufacturers can determine the initial flat plate which is required to form the design shape. In this paper, an algorithm for optimal approximated development of a general curved surface, including both single- and double-curved surfaces, is established by minimizing the strain energy of deformation from its planar development to the design surface. The unfolding process is formulated into a constrained nonlinear programming problem, based on the deformation theory and finite element. Constraints are subjected to the characteristics of the fabrication method. And the design surface, or the curved shell plate is subdivided by automatic mesh generation.

• 한국산업융합학회 논문집
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• 제18권3호
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• pp.167-172
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• 2015

In this paper, we propose a new approach to design and control a smart gripper of robot system. A control method for flexible grasping a object in partially unknown environment was proposed, where a proximate sensor detecting the distance between the fingertip and object was used. Based on the proximate sensor signal the finger motion controller could plan the grasping process divided in three phases. The first step is scanning process which two first joints were moved to mid-position of the detected range by a state-variable feedback position controller, after the scanning was finished. The contact force of fingertip was then controlled using the detection sensor of the servo controller for finger joint control. The proposed grasping planning was tested on rectangular bar.

• 한국공작기계학회논문집
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• 제18권2호
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• pp.207-213
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• 2009

The bundling process is the final step in vegetable manufacturing, however, the process is a little difficult to be automatized, because vegetable has the physical properties of roughness, softness, and fragility etc. In this paper, we proposed an automatic bundling mechanism for vegetable based on the heat melt sticking. The proposed mechanism consists of three modules, one module is the moving part for aligning of the vegetable shape and adjusting of the vegetable tension, second module is the arm driving part for the vegetable binding and the band roll releasing, and third module is band joining, band cutting, and band feeding part for the vegetable binding continuously. Through this research, Using the SMO(SimDesigner Motion) module, we optimize condition of mechanical movement of the bundling mechanism. This bundling system designed in order to binding 288 bundle/hour.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1999년도 춘계 학술대회논문집
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• pp.35-47
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• 1999

The development of a parallelized aerodynamic simulation process involving moving bodies is presented. The implementation of this process is demonstrated using a fully systemized Chimera methodology for steady and unsteady problems. This methodology consist of a Chimera hole-cutting, a new cut-paste algorithm for optimal mesh. interface generation and a two-step search method for donor cell identification. It is fully automated and requires minimal user input. All procedures of the Chimera technique are parallelized on the Cray T3E using the MPI library. Two and three-dimensional examples are chosen to demonstate the effectiveness and parallel performance of this procedure.

• 한국CDE학회논문집
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• 제7권3호
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• pp.190-201
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• 2002

Surfaces of many engineering structures, specially, those of ships and airplanes are commonly fabricated as doubly curved shapes as well as singly curved surfaces to fulfill functional requirements. Given a three dimensional design surface, the first step in the fabrication process is unfolding or planar development of this surfaces into a planar shape so that the manufacturer can determine the initial shape of the flat plate. Also a good planar development enables the manufacturer to estimate the strain distribution required to form the design shape. In this paper, an algorithm for optimal approximated development of a general curved surface, including both singly and doubly curved surface is developed in the sense that the strain energy from its planar development to the design surface is minimized, subjected to some constraints. The development process is formulated into a constrained nonlinear programming problem, which is on basis of deformation theory and finite element. Constraints are subjected to characteristics of the fabrication method. Some examples on typical surfaces and the practical ship surfaces show the effectiveness of this algorithm.

• 상하수도학회지
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• 제13권3호
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• pp.42-55
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• 1999

A mathematical model for biological nutrient removal in a sequencing batch reactor process, which is based on the IAWQ Activated Sludge Model No. 2 with a few modifications, has been developed. Twenty water quality components and twenty three kinetic equations are incorporated in the model. The model is structured in the matrix form based on the law of mass conservation using stoichiometry and kinetic equations. Stoichiometric coefficients and kinetic parameters included in the model equations are chosen from the literature. A multistep predictor-corrector algorithm of variable step-size is adopted for solving the vector nonlinear ordinary differential equations. The simulation for experimental results is conducted to evaluate the validity of the model and to calibrate coefficients and parameters. The simulation using the model well represents the experimental results from laboratory. The mathematical model developed in this study may be utilized for the design and operation of a sequencing batch reactor process under the steady and unsteady-state at various environmental conditions.

• ETRI Journal
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• 제43권1호
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• pp.141-151
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• 2021

Several methods exist for detecting hacking programs operating within online games. However, a significant amount of computational power is required to detect the illegal access of a hacking program in game clients. In this study, we propose a novel detection method that analyzes the protected memory area and the hacking program's process in real time. Our proposed method is composed of a three-step process: the collection of information from each PC, separation of the collected information according to OS and version, and analysis of the separated memory information. As a result, we successfully detect malicious injected dynamic link libraries in the normal memory space.

• 대한인간공학회지
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• 제28권2호
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• pp.57-67
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• 2009

This study proposed a practical metaphor development process that consisted of three steps: 1) identifying major functions, 2) developing metaphor candidates, and 3) evaluating appropriateness of the candidates. In the first step, a total of 27 functions might be implemented in a driver information system (DIS) in the near future. Then, three metaphor candidates were selected from existing metaphors, which were reported to be more practical than others by previous studies. Finally, the candidates were evaluated on their appropriateness for driver information systems by using a quick and simple survey. As a result, two metaphors (a PC and a secretary) were identified as the most appropriate ones. The two metaphors can be used to design a variety of interfaces and interactions for driver information systems. In addition, the development process proposed in this study could be applied to developing metaphors for emerging devices with a variety of functions (e.g. PMPs, MP3s, and electronic dictionaries) as well as driver information systems.

• 한국전문물리치료학회지
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• 제22권4호
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• pp.51-61
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• 2015

The purpose of this study were to translate the Fullerton Advanced Balance (FAB) scale into Korean and to verify the content validity by utilizing a back-translation method with a view to assessing balance function and the risk of falling in a clinical research setting. This research was conducted in six steps. First, three Korean physical therapists translated the FAB scale into Korean. Second, two bilingual professors of physical therapy and a physical therapist evaluated translation conformity of Korean-translated FAB scale. In the third and fourth steps, twelve physical therapists evaluated the degree of translation comprehension, and a translator back-translated the Korean FAB scale into the original language. Fifth, a bilingual professor of physical therapy and two native speakers evaluated the technical and conceptual equivalence between the original and translation versions. In this process, inappropriate translated items were revised using recommended substitute words or sentences, and all items were evaluated on the basis of three points or more on a rating scale in terms of translation comprehension, and the technical and conceptual equivalence of the back-translation. In the sixth and last step, the translation verification committee completed the final Korean version. The above process indicated that the content validity of the Korean-translated FAB scale was established by means of systematic translation methods, and it can therefore be used to assess balance function and the risk of falls in a clinical research setting.

• 청정기술
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• 제28권1호
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• pp.32-37
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• 2022

Food waste is produced from food factories, food services, and home kitchens. The generated mass reached 5.4 million tons/year in 2020. The basic management technology for such waste has been biological degradation under an anaerobic environment. However, the whole process is intrinsically slow and considerably affected by the inner physicochemical properties of the waste and other surrounding conditions, which makes optimization of the process difficult. The most promising options to counter this massive generation of waste are eco-friendly treatments or recycling. As a preliminary step for these options, attempts were made to evaluate the feasibility and usability of three simulative models based on reaction kinetics. Model (A) predicted relative changes over reaction time for reactant, intermediate, and product. Overall, an increased reaction rate produced less intermediate and more product, thereby leading to a shorter total reaction time. Particle diminishing model (B) predicted reduction of the total waste mass. The smaller particles diminished faster along with the dominant effect of microbial reaction. In Model (C), long-chain cellulose was predicted to transform into reducing sugar. At a standard condition, 48% of cellulose molecules having 10⁵ repeating units turned into reducing sugar after 100 h. Also it was found that the optimal enzyme concentration where the highest amount of remnant sugar was harvested was 1 mg L^-1.