• Proceedings of the KSME Conference
• /
• 2008.11a
• /
• pp.1063-1068
• /
• 2008

A lens system of a camera module for mobile phones is comprised of the composition and design of various shapes of lens. To improve responses such as the modular transfer function (MTF), a lens system should always be constructed by considering uncertainty that can be caused by manufacturing and assembly error. In this study, tolerance optimization using the Latin Hypercube Sampling (LHS) technique is performed. In order to reduce the computational burden of the tolerance optimization process and decrease the influence from numerical noise effectively, we use the Progressive Quadratic Response Surface Modeling (PQRSM), which is one of Sequential Approximate Optimization (SAO) techniques. Using this method, we achieved optimal tolerance for each lens and obtained reliability for satisfying user‘s requirements. In addition, through the design process the manufacturing and assembly cost of a lens system was reduced.

• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.400-400
• /
• 2000

This paper purposed that verify the validity of Petri Net method for control progressive increase of system complexity, before extend the realized single robot system to multi-robot system. An autonomous mobile robot(AMR) needs decision making, motion control, path planning, tracking a path, obstacle avoidance, and sensor fusion, to complete its task. An AMR integrates and operates these technics through a consistent command system. An error in a command hierarchy which is like duplication or omission of a control command hierarchy for each module results in serious problems. This paper minimizes the error by modeling each module and whole system using Petri Net graphical representation and applies it to the exploration task of an AMR

• The Journal of Information Systems
• /
• v.17 no.3
• /
• pp.235-254
• /
• 2008

This article describes the latest development of a generic approach to detecting emerging trends and transient in scientific literature. The work makes substantial theoretical and methodological contributions to progressive Information analysis. A specialty is conceptualized as a time variant duality research front concepts in information science. A research front is defined as an emergent and transient grouping of concepts and underlying research issues. The contributions of the approach is that the nature of an intellectual base is algorithmically and temporally identified by emergent research-front terms. The modeling process is implemented in RADERS, and applied to the analysis of telecommunication field. Practical implications of the work are discussed. A number of challenges and opportunities for future studies are identified.

• Korean Journal of Child Studies
• /
• v.21 no.2
• /
• pp.33-44
• /
• 2000

In this study, a random sample of 111 six-year-old children were assigned to one of 3 experimental conditions: categorization training using cognitive apprenticeship, categorization training using metacognitive procedures, and no categorization training. Level of intelligence was measured by Raven's(1986) Coloured Progressive Matrics(CPM). No difference was found between apprenticeship and metacognitive training in the high CPM children. In the middle and low CPM levels, cognitive apprenticeship training was more efficient than metacognitive training. This indicates that cognitive apprenticeship, which emphasizes the thinkaloud procedure of both the experts and the novice though modeling and coaching for self-implementation, is a more effective approach than the metacognitive approach for categorization in middle and low CPM children.

• Structural Engineering and Mechanics
• /
• v.24 no.2
• /
• pp.181-194
• /
• 2006

The masonry is a complex heterogeneous material and its shear deformation and fracture is associated with very complicated progressive failures in masonry structure, and is investigated in this paper using a mesoscopic mechanical modelling, Considering the heterogeneity of masonry material, based on the damage mechanics and elastic-brittle theory, the newly developed Material Failure Process Analysis (MFPA) system was brought out to simulate the cracking process of masonry, which was considered as a three-phase composite of the block phase, the mortar phase and the block-mortar interfaces. The crack propagation processes simulated with this model shows good agreement with those of experimental observations by other researchers. This finding indicates that the shear fracture of masonry observed at the macroscopic level is predominantly caused by tensile damage at the mesoscopic level. Some brittle materials are so weak in tension relative to shear that tensile rather than shear fractures are generated in pure shear loading.

• Asia pacific journal of information systems
• /
• v.9 no.1
• /
• pp.115-142
• /
• 1999

Legacy applications are valuable assets that should be integrated into next generation business systems. To gain this advantage, progressive companies can reverse engineer the legacy business operations. This paper presents a form-driven object-oriented reverse engineering(FORE) methodology by the use of business forms to recover semantics of legacy applications. They retain the user-oriented contents of business and thus are easily understandable. Our form driven object-oriented reverse engineering methodology consists of five phases: form and usage analysis, form object slicing, object structure modeling, scenario design, and model integration. Knowledge about form structure and user interaction with legacy applications is used to capture the design semantics. An object model, which consists of an object structure model and scenario results from such form knowledge. The resulting object model is more likely to help reverse engineers understand and reuse legacy systems.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 2006.03a
• /
• pp.168-179
• /
• 2006

This paper summarizes full-scale test results on CFT column-to-flat plate connections subjected to gravity loading. CFT construction has gained wide acceptance in a relatively short time in domestic building construction practice due to its various structural and construction advantages. However, efficient details for CFT column to flat plate connections have not been proposed yet. Based on the strategies that maximize economical field construction, several connecting schemes were proposed and tested. Test results showed that the proposed connections can exhibit punching shear strength and connection stiffness exceeding those of R/C flat plate counterparts. A semi-analytical procedure is presented to model the behavior of CFT column-to-flat plate connections. The five parameters to model elastic to post-punching catenary action range are calibrated based on the limited test data of this study. The application of the proposed modeling procedure to progressive collapse prevention design is also illustrated.

• Interaction and multiscale mechanics
• /
• v.5 no.2
• /
• pp.157-168
• /
• 2012

The dilatancy of granular materials has significant influence on its mechanical behaviors. The dilation angle is taken as a constant in conventional associated or non-associated flow rules based on Drucker-Prager yields theory. However, various experimental results show the dilatancy changes during progressive failure of granular materials. A non-associated flow rule with evolution of dilation angle is adopted in this study, and Cosserat continuum theory is used to describe the behaviors of granular materials for considering to some extent the its internal structure. Numerical examples focus on the bearing capacity and localization of granular materials, and results illustrate the capability and performance of the presented model in modeling the effect on failure behavior of granular materials.

• Nuclear Engineering and Technology
• /
• v.55 no.11
• /
• pp.4134-4145
• /
• 2023

This paper proposes strain-based failure model of A533B1 pressure vessel steel to simulate failure, followed by application to OECD lower head failure (OLHF) test simulation for experimental validation. The proposed strain-based failure model uses simple constant and linear functions based on physical failure modes with the critical strain value determined either using the lower bound of true fracture strain or using the average value of total elongation depending on the temperature. Application to OECD Lower Head Failure (OLHF) tests shows that progressive deformation, failure time and failure location can be well predicted.

• Nuclear Engineering and Technology
• /
• v.55 no.11
• /
• pp.4146-4158
• /
• 2023

This paper proposes a combined plastic and creep constitutive model of A533B1 pressure vessel steel to simulate progressive deformation of nuclear pressure vessels under severe accident conditions. To develop the model, recent tensile test data covering a wide range of temperatures (from RT to 1,100 ℃) and strain rates (from 0.001%/s to 1.0%/s) was used. Comparison with experimental data confirms that the proposed combined plastic and creep model can well reflect effects of temperature and strain rate on tensile behaviour up to failure. In the companion paper (Part II), the proposed model will be used to simulate OECD lower head failure (OLHF) test data.