• Proceedings of the KSME Conference
• /
• 2003.11a
• /
• pp.916-921
• /
• 2003

In most industrial applications, the geometrical complexity is combined with the moving boundaries. These problems considerably increase the computational difficulties since they require, respectively, regeneration and deformation of the grid. As a result, engineering flow simulation is restricted. In order to solve this kind of problems the immersed boundary method was developed. In this study, the immersed boundary method is applied to the numerical simulation of stationary, rotating and oscillating cylinders in the 2-dimensional square cavity. No-slip velocity boundary conditions are given by imposing feedback forcing term to the momentum equation. Besides, this technique is used with a second-order accurate interpolation scheme in order to improve the accuracy of flow near the immersed boundaries. The governing equations for the mass and momentum using the immersed boundary method are discretized on the non-staggered grid by using the finite volume method(FVM). This study presents the possibility of the immersed boundary method to apply to the complex flow experienced in the industrial applications.

• Journal of the Korea Fashion and Costume Design Association
• /
• v.26 no.1
• /
• pp.111-126
• /
• 2024

The purpose of this study is to analyze the mediating effect of flow in the quality of customizing e-services and customer loyalty, with a view to providing a realistic strategy for the development of fashion customizing services. For this study, a total of 489 adult women in their 20s and older participated in a survey, and the responses were analyzed using SPSS 23.0 and AMOS 23.0 . The findings of the analysis were as follows. First, the ease of use, privacy, individual designs, order status, and accuracy of orders, which were the factors of fashion customizing e-service quality, had a significant and positive impact on flow. Second, the ease of use, order status, and order accuracy, which were the factors of fashion customizing e-service quality, had a significant and positive impact on customer loyalty. Third, the flow of the fashion customizing service had a significant and positive impact on customer loyalty. Fourth, in the relationship between fashion customizing e-service quality and customer loyalty, flow had a significant mediating effect. The findings of this study are expected to be useful data for the fashion industry providing a set of criteria for optimized customizing e-services for customers.

• Proceedings of the KSRS Conference
• /
• 2002.10a
• /
• pp.708-708
• /
• 2002

Recent developments in sensor technologies have provided remotely sensed data with very high spatial resolution. In order to fully utilize the potential of high resolution images, new image classification strategies are necessary. Unfortunately, the high resolution images increase the spectral within-field variability, and the classification accuracy of traditional methods based on pixel-based classification algorithms such as Maximum-Likelihood method may be decreased (Schiewe 2001). Recent development in Object Oriented Classification based on image segmentation algorithms can be used for the classification of forest patches on rugged terrain of Korea. The objectives of this paper are as follows. First, to compare the pros and cons of image classification methods based on pixel-based and object oriented classification algorithm for the forest patch classification. Landsat ETM＋ data and IKONOS data will be used for the classification. Second, to investigate ways to increase classification accuracy of forest patches. Supplemental data such as DTM and Forest Type Map of 1:25,000 scale are used for topographic correction and image segmentation. Third, to propose the best classification strategy for forest patch classification in terms of accuracy and data requirement. The research site for this paper is Namhansansung Provincial Park located at the eastern suburb of Seoul Metropolitan City for its diverse forest patch types and data availability. Both Landsat ETM＋ and IKONOS data are used for the classification. Preliminary results can be summarized as follows. First, topographic correction of reflectance is essential for the classification of forest patches on rugged terrain. Second, object oriented classification of IKONOS data enables higher classification accuracy compared to Landsat ETM＋ and pixel-based classification. Third, multi-stage segmentation is very useful to investigate landscape ecological aspect of forest communities of Korea.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.12 no.2
• /
• pp.710-726
• /
• 2018

This paper presents an extended particle filter to increase the accuracy and decrease the computation load of vehicle tracking. Particle filter has been the subject of extensive interest in video-based tracking which is capable of solving nonlinear and non-Gaussian problems. However, there still exist problems such as preventing unnecessary particle consumption, reducing the computational burden, and increasing the accuracy. We aim to increase the accuracy without an increase in computation load. In proposed method, we calculate the direction angle of the target vehicle. The angular difference between the direction of the target vehicle and each particle of the particle filter is observed. Particles are filtered and weighted, based on their angular difference. Particles with angular difference greater than a threshold is eliminated and the remaining are stored with greater weights in order to increase their probability for state estimation. Threshold value is very critical for performance. Thus, instead of having a constant threshold value, proposed algorithm updates it online. The first advantage of our algorithm is that it prevents the system from failures caused by insufficient amount of particles. Second advantage is to reduce the risk of using unnecessary number of particles in tracking which causes computation load. Proposed algorithm is compared against camshift, direction-based particle filter and condensation algorithms. Results show that the proposed algorithm outperforms the other methods in terms of accuracy, tracking duration and particle consumption.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.42 no.4
• /
• pp.291-297
• /
• 2014

A Design of Experiments(DOE) approach to an experimental study of fuselage drag and stability characteristics of a helicopter configuration was applied to achieve an accuracy improvement in the wind tunnel testing. The impact of blocking the test was assessed by comparing the ANOVA table for the blocked and unblocked cases. For a second-order response model, the role of blocking resulted in a substantial increase in the accuracy of test results. These accuracy improvement could be achieved through randomization, blocking, and replication of the data points i.e. a re-ordering of the test sequence where the data were acquired.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• v.18 no.1
• /
• pp.51-60
• /
• 2014

The Shortley-Weller method is a basic finite difference method for solving the Poisson equation with Dirichlet boundary condition. In this article, we review the analysis for supra-convergence of the Shortley-Weller method. Though consistency error is first order accurate at some locations, the convergence order is globally second order. We call this increase of the order of accuracy, supra-convergence. Our review is not a simple copy but serves a basic foundation to go toward yet undiscovered analysis for another supra-convergence: we present a partial result for supra-convergence for the gradient of solution.

• International conference on construction engineering and project management
• /
• 2009.05a
• /
• pp.1068-1074
• /
• 2009

The progress is widely used as a critical index for successful construction project management. In spite of the importance of progress measurement, the excessive management effort to collect and maintain detailed data has been highlighted as a major barrier to measurement of highly accurate progress. In order to reduce the required workload and to enhance accuracy, several researches have been conducted. These researches can be categorized into two groups. First group focuses on automated data collection utilizing advanced technologies only for limited construction tasks. The second group is a research area where the standard progress measurement methodologies encompassing entire construction tasks are investigated. Topics include the adjusting the level of details, standardizing work processes, and applying flexible WBS. However, the techniques for automated data collection are not fully investigated yet in the second group. Combining these two research areas can provide a solution for more effective progress management in terms of enhancing accuracy and optimizing workload. However, there has been no comprehensive research addressing these two research groups in an integrated manner. In this context, the purpose of this paper is to propose a methodology that identifies the most suitable measurement method and data acquisition technology (e.g., GPS, RFID, etc.) for entire construction tasks of a project. The proposed methodology in this paper will be able to facilitate the selection process of data acquisition technologies for entire construction tasks of a project and to support the overall enhancement of automated progress management.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.8 no.2
• /
• pp.127-136
• /
• 2016

Springing is the resonance phenomenon of a ship hull girder with incoming waves having the same natural frequency of the ship. In this study, a simple and reliable calculation method was developed based on quadratic strip theory using the Timoshenko beam approach as an elastic hull girder. Second-order hydrodynamic forces and Froude-Krylov forces were applied as the external force. To improve the accuracy of the strip method, the variation in the added mass along the ship hull longitudinal direction, so called tip-effect, was considered. The J-factor was also employed to compensate for the effect of three-dimensional fluid motion on the two-node vibration of the ship. Using the developed method, the first- and second-order vertical bending moments of the Flokstra ship were compared. A comparative study was also carried out for a uniform barge ship and a 10,000 TEU container ship with the respective methods including the J-factor and tip-effect.

• The Journal of Asian Finance, Economics and Business
• /
• v.8 no.1
• /
• pp.939-950
• /
• 2021

The purpose of this research is to investigate the factors affecting Thai commercial bank users' behavioral intention towards QR code payment system via mobile banking applications. The researchers conducted the study based on quantitative research approach. Non-probability sampling method such as the quota and convenience sampling was applied as sampling technique. A self-administered questionnaire was distributed. The data was collected from 1,800 respondents living in Bangkok, who have had an experience with QR code payment system with the top-three mobile banking applications in Thailand. This study concentrates on confirmatory factor analysis and structural equation modeling as a statistical tool to examine the data, model accuracy, and influence of critical variables. In addition, the researchers applied the first-order and second-order techniques to examine the relationship between constructs. Adoption readiness and perceived risk were second-order constructs. The results reveled that compatibility has an impact on attitude towards QR code payment. Moreover, adoption readiness, compatibility, attitude, and personal innovativeness are statistically significant that impact behavioral intention towards QR code payment. The strongest antecedents of behavioral intention were compatibility, attitude, adoption readiness, and personal innovativeness, respectively. Surprisingly, perceived risk and perceived trust do not statistically have a significant impact on behavioral intention towards QR code payment.

• Steel and Composite Structures
• /
• v.42 no.1
• /
• pp.75-90
• /
• 2022

The pointwise equilibrium polynomial (PEP) element considering local second-order effect has been widely used in direct analysis of many practical engineering structures. However, it was derived according to Euler-Bernoulli beam theory and therefore it cannot consider shear deformation, which may lead to inaccurate prediction for deep beams. In this paper, a novel beam-column element based on Timoshenko beam theory is proposed to overcome the drawback of PEP element. A fifth-order polynomial is adopted for the lateral deflection of the proposed element, while a quadric shear strain field based on equilibrium equation is assumed for transverse shear deformation. Further, an additional quadric function is adopted in this new element to account for member initial geometrical imperfection. In conjunction with a reliable and effective three-dimensional (3D) co-rotational technique, the proposed element can consider both member initial imperfection and transverse shear deformation for second-order direct analysis of frame structures. Some benchmark problems are provided to demonstrate the accuracy and high performance of the proposed element. The significant adverse influence on structural behaviors due to shear deformation and initial imperfection is also discussed.