• Journal of the Society of Naval Architects of Korea
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• v.53 no.5
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• pp.388-399
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• 2016

A motion analysis of an underwater towed cable is a complex task due to its nonlinear nature of the problem. The major source of the nonlinearity of the underwater cable analysis is that the motion of the cable involves large rigid-body motion. This large rigid-body motion makes difficult to use standard displacement-based finite element method. In this paper, the authors apply recently developed nodal position-based finite element method which can deal with the geometric nonlinearity due to the large rigid-body motion. In order to enhance the stability of the large-scale nonlinear cable motion simulation, an efficient time-integration scheme is proposed, namely predictor/multi-corrector Newmark scheme. Three different predictors are introduced, and the best predictor in terms of stability and robustness for impulsive cable motion analysis is proposed. As a result, the nonlinear motion of underwater cable is predicted in a very efficient manner compared to the classical finite element of finite difference methods. The efficacy of the method is demonstrated with several test cases, involving static and dynamic motion of a single cable element, and also under water towed cable composed of multiple cable elements.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.5
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• pp.1043-1058
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• 1990

The Strain rate effect in electro-magnetic forming, which is one of the high velocity forming methods, is studied by the finite element method in this paper. The forming process is simplified by neglecting the coupling between magnetic field and work-piece deformation, and the impulsive magnetic pressure is regarded as inner pressure load. A rate-dependent elasto-plastic material model, of which tangential modulus depends of effective strain rate, is proposed. The model is shown to well describe the transient increase of yield stresses, the decreases of the final displacement and yield stress, the decrease of the difference in the distribution of deformation along the axial direction, and the change of deformation mechanism due to strain rate effect. As a result, displacement, final deformed shape, radial velocity, deformation energy, and the changes of effective stress, effective strain and effective strain rate through plastic working are given. Based on the results, the effectiveness of this model and the strain rate effect of the deformation process of the work-piece are discussed.

• Korean journal of food and cookery science
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• v.30 no.3
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• pp.291-306
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• 2014

The purpose of this study was to examine the use of social commerce restaurant products by college students according to demographic characteristics and eating out behavior. The questionnaire for the survey was distributed to 450 college students, who have experiences of purchasing a restaurant product on social commerce, with 286 responses used for analysis. From the result, college students frequently use smart phones and SNS for making such purchases. While the awareness of social commerce was high, they sometimes visited the websites and purchased products. The awareness and purchase experience of Coupang and Ticket Monster turned out to be the highest. The most frequently purchased product was restaurant discount coupons, followed by fashion/accessories, movie or concert tickets, food products, and beauty shop discount coupons. The discount rate was mostly 30 to 40% on average. The most significantly considered matter in purchasing products and services was product quality, followed by discount rate and consumer review. The respondents ate out at least 3 to 5 times a week, spent $100,000{\leq}200,000$ won, and were generally satisfied with the restaurant products from social commerce sites. The main satisfaction reason was price, whereas the dissatisfaction reason was false and puffy advertising. Service quality improvement and variety of category were the most necessary factors for improvement. Among the demographic characteristics, there was a difference in purchase expenditure of social commerce restaurant products, as well as purpose, companion, time used and word-of-mouth experience according to gender. According to grade, there was a difference in purchase expenditure, companion, area of use and impulsive purchase. Among the eating out behavior, there was a difference in purpose, companion and word-of-mouth experience according to the eating out frequency. Meanwhile, there was a difference in purchase expenditure, companion, time used, word-of-mouth experience and tool according to the eating out cost.

• Journal of Distribution Science
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• v.16 no.9
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• pp.59-63
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• 2018

Purpose - It has already been proved that 'mood' as the physical environment of shopping affects consumers' main sensory channels such as sight, hearing, smell, touch. However, there is no consensus on how the olfactory cue influences the customers in the shopping environment. In this study, we examine the previous studies on how the olfactory cue affects the customers in the shopping environment and present a clear direction as a suggestion for progressive research. Research design, data, and methodology - It is not important to use a lot of unconditional fragrance, but it should be exposed to the environment that suits the proper fragrance. In recent years, meaningful research on store fragrance has been slowly increasing. As a result, studies on the fragrance effects of retail stores have been conducted to verify the relevance of fragrance suitability in stores and consumer spending scale. Results - The fragrance appropriate for each store can not be uniformly specified as any fragrance. This is because external variables such as time, season, temperature, lighting, density of shoppers, and music in the store also affect customer evaluation. For example, using an unsuitable fragrance may encourage customers to leave the store quickly by restraining impulsive purchases or by disturbing concentration. The store manager should also be interested in using fragrances that are proven and effective in the store environment, but they should also have the ability to easily manipulate and manage the fragrances very appropriately according to changes in the store environment. Store managers should observe consumer preferences and responses according to their goals and strategies, and then systematically manage and store information about the fragrance appropriate to the store. Conclusions - In the future, the fragrance marketing researcher needs to consider the spatial form and density of the customer. In practice, managers operating a retail store should check the most appropriate store density(congestion) according to the size and spatial characteristics of the store and maintain the ideal conditions. To do this, it is necessary to pay attention to how to select and control sensory elements such as fragrance(olfactory), music(auditory), and lighting(visual).

• The Journal of Korean Association of Computer Education
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• v.10 no.6
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• pp.29-38
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• 2007

The purpose of this study is developing of Korean scale for measuring elementary school pupil's online game addiction tendency by scientific development process. The pilot test was conducted in three times, and the items analysis, reliability analysis, and factor analysis was conducted at every test, so the inquiries for main survey composed of 30 inquiry items was decided. Some referential variables was included in the inquiries for main survey such as inquiry items for testing the actual using conditions and attitude of online game, the aggressive behavior scale, the impulsive behavior scale, the solitude scale, and the self-control scale. 2,584 fifth and sixth grade students in elementary school participated in main survey. For main survey results, items analysis and reliability analysis was conducted and validity was verified by exploratory factor analysis and correlation analysis. Finally, the final inquiry items composed of 7 factors, 30 items and the grouping criterion were developed through the standardization process.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.1
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• pp.65.1-65.1
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• 2013

The 2011 August 09 Flare is one of the largest X-ray flares of Sunspot Cycle 24 to attract a lot of attention for its various activities detected in coronal images. In this study we concern ourselves mostly on information of high energy electrons produced during this flare provided by hard X ray data from the Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) and radio data from the Korean Solar Radio Burst Locator (KSRBL) and Ondrejov. EUV images obtained by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory are used to provide the context of magnetic reconnection. In our results, (1) HXR spectra have a rich spectral morphology. Initially it could be fit by one thermal component (T~30MK) and one single power law nonthermal spectrum, but later a better fit could be made by introducing an additional thermal component (T~55 MK). (2) Time delays between the KSRBL burst and the RHESSI hard X-ray emission were found which are more obvious at low frequencies and insignificant at high frequencies. (3) The HXR source lies in the core of the quadrupolar active region. In our interpretation based on AIA 94 A images, the outer part of the active region erupted to be blown out, leaving the intense hard X-ray emission concentrated in the core. We relate the appearance of the second thermal component to the evolution of the AIA 171 and 94 A images. The time delays of microwave peaks to HXR peaks are interpreted as indicating presence of trapped electrons in larger closed magnetic loops. With these result we conclude that the hard X ray and microwaves are due to impulsive acceleration in the low and high heights and a sigmoidal reconnection scenario.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.1033-1036
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• 2008

In this paper, the analysis of impact damage behavior of a reinforced concrete structure that undergoes both a shock impulsive loading and an impact loading due to the air blast induced from an explosion is performed. Firstly, a pair of multiple loadings are selected from the scenario that an imaginary explosion accident is assumed. The RC structures strengthened with glass fiber reinforced polymer (GFRP) composites are considered as a scheme for retrofitting RC wall structures subjected to multiple explosive loadings and then the evaluation of the resistant performance against them is presented in comparison with the result of the evaluation of a RC structure without a retrofit. Also, in order to derive the result of the analysis similar to that of real explosion experiments, which require the vast investment and expense for facilities, the constitutive equation and the equation of state (EOS) which can describe the real impact and shock phenomena accurately are included with them. In addition, the numerical simulations of two concrete structures are achieved using AUTODYN-3D, an explicit analysis program, in order to prove the retrofit performance of a GFRP-strengthened RC wall structure.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.1
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• pp.34-39
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• 2009

As a subjective recognition effect, human's emotion has impulsive characteristic and it expresses intentions and needs unconsciously. These are pregnant with information of the context about the ubiquitous computing environment or intelligent robot systems users. Such indicators which can aware the user's emotion are facial image, voice signal, biological signal spectrum and so on. In this paper, we generate the each result of facial and voice emotion recognition by using facial image and voice for the increasing convenience and efficiency of the emotion recognition. Also, we extract the feature which is the best fit information based on image and sound to upgrade emotion recognition rate and implement Multi-Modal Emotion recognition system based on feature fusion. Eventually, we propose the possibility of the ubiquitous computing service reasoning method based on Bayesian Network and ubiquitous context scenario in the ubiquitous computing environment by using result of emotion recognition.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.1
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• pp.33-39
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• 2018

An additive noise reduction algorithm for a mass spectrum analyzer is proposed. From the measured ion signal, we first used an estimated threshold from the mode of the measured signal to eliminate background noises with the white Gaussian characteristics. Also, a signal block corresponding to each mass index is constructed to perform a second order curve fitting and a linear approximation to signal block. In this process, the effective signal block composed of only the ion signal can be reconstructed by removing the impulsive noises and the sample signals which are insufficient to be viewed as normal ion signals. By performing curve fitting on the effective signal block, the noise-free mass spectrum can be obtained. To evaluate the performance of the proposed method, a simulation was performed using the signals acquired from the development equipment. Simulation results show the validity of the threshold setting from the mode and the superiority of the proposed curve fitting and linear approximation based noise canceling algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.5C
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• pp.542-549
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• 2007

Recently, many research activities in the image processing area are concentrated on developing new algorithms by finding the solution of the 'diffusion equation'. The diffusion algorithms are expected to be utilized in numerous applications including noise removal and image restoration, edge detection, segmentation, etc. In this paper, at first, it will be shown that the anisotropic diffusion algorithms have the similar structure with the adaptive FIR filters with cross-shaped 5-tap kernel, and this relatively small-sized kernel causes many iterating procedure for satisfactory filtering effects. Moreover, it will also be shown that lots of modifications which are adopted to the conventional Gaussian diffusion method in order to weaken the edge blurring nature of the linear filtering process increases another computational burden. We propose a new Median diffusion scheme by replacing the adaptive linear filters in the diffusion process with the AWM (Adaptive Weighted Median) filters. A diffusion-equation-based adaptation scheme is also proposed. With the proposed scheme, the size of the diffusion kernel can be increased, and thus diffusion speed greatly increases. Simulation results shows that the proposed Median diffusion scheme outperforms in noise removal (especially impulsive noise), and edge preservation.