• Steel and Composite Structures
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• v.18 no.2
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• pp.325-344
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• 2015

Experimental tests on cellular beams with sinusoidal openings showed two main failure modes around the openings. They concern the formation of four plastic hinges and the local instability of the sinusoidal part of the opening. In parallel, numerical analysis of the sinusoidal part of the opening revealed the existence of an elastic rotational restraint between the intermediate web-post and the adjacent opening panel. The aim of the present study is to present an approach to quantify this rotational restraint. Through the response surface method, a mathematical model is proposed. It shows a great ability to predict the rotational restraint value as a function of the geometrical parameters of the opening. This model can be used to perform an extensive study with various geometrical configurations of beams with the aim to develop a reliable and realistic analytical model predicting the resistance of the sinusoidal openings.

• Convergence Security Journal
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• v.23 no.5
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• pp.101-106
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• 2023

Recently, cyberattacks are increasing in social engineering attacks using intelligent and continuous phishing sites and hacking techniques using malicious code. As personal security becomes important, there is a need for a method and a solution for determining whether a malicious URL exists using a web application. In this paper, we would like to find out each feature and limitation by comparing highly accurate techniques for detecting malicious URLs. Compared to classification algorithm models using features such as web flat panel DB and based URL detection sites, we propose an efficient URL anomaly detection technique.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.10a
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• pp.227-234
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• 2001

The lifting and lowering supports method was recently developed in steel box girder bridge. It has many advantages by lifting and lowering of inner supports and filled concrete. This method reduces an amount of steel and height of girders. It is one of the methods used to effectively increase the use of structural material. However, if there is too much lifting of inner supports, it is possible to cause buckling of the compression flange or web panel. Therefore it needs a proper number of longitudinal and transvers stiffener.

• Korean Business Review
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• v.15
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• pp.79-97
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• 2002

In this study, an analytical CRM for customer segmentation is exercised by integrating and analyzing the customer profile data and the access data to a particular web site. We believe that effective customer segmentation will be possible with a basis of the understanding of customer characteristics as well as behavior on the web. One of the critical tasks in the web data-mining is concerned with both 'how to collect the data from the web in an efficient manner?' and 'how to integrate the data(mostly in a variety of types) effectively for the analysis?' This study proposes a panel approach as an efficient data collection method in the web. For the customer data analysis, OLAF and a tree-structured algorithm are applied in this study. The results of the analysis with both techniques are compared, confirming the previous work which the two techniques are inter-complementary.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.3 s.147
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• pp.392-398
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• 2006

A prototype of MES(Manufacturing Execution System) applied to panel assembly shop is implemented by using PDA(Personal Digital Assistant) and wireless database web server. The system is developed based on the Dot Net framework. The prototype can exchange the manufacturing execution data between production managers in the control room and workers in the factory through wireless internet communication. Manufacturing model of the panel shop is designed by using IDEF0 and UML method to understand the characteristics of the information and the data entities from the PPR-S view. Several issues in the shop were revealed from the manufacturing model analysis. The most typical problem was the lack of information sharing between the managing workers and the assembly workers. The problem prevents the workers and labors from sharing the process information and continuous workpiece flow In interactive way. To increase the information and data flow, a wireless internet based system is implemented and PDAs are linked together to exchange the process planning data and in-process data between the workers. It is anticipated that PDA and the implemented system can enable the process control at each process stages to obtain the well-organized operation.

• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.3
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• pp.348-363
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• 2013

The use of I-Core sandwich panel has increased in cruise ship deck structure since it can provide similar bending strength with conventional stiffened plate while keeping lighter weight and lower web height. However, due to its thin plate thickness, i.e. about 4~6 mm at most, it is assembled by high power $CO_2$ laser welding to minimize the welding deformation. This research proposes a volumetric heat source model for T-joint of the I-Core sandwich panel and a method to use shell element model for a thermal elasto-plastic analysis to predict welding deformation. This paper, Part I, focuses on the heat source model. A circular cone type heat source model is newly suggested in heat transfer analysis to realize similar melting zone with that observed in experiment. An additional suggestion is made to consider negative defocus, which is commonly applied in T-joint laser welding since it can provide deeper penetration than zero defocus. The proposed heat source is also verified through 3D thermal elasto-plastic analysis to compare welding deformation with experimental results. A parametric study for different welding speeds, defocus values, and welding powers is performed to investigate the effect on the melting zone and welding deformation. In Part II, focuses on the proposed method to employ shell element model to predict welding deformation in thermal elasto-plastic analysis instead of solid element model.

• Journal of Families and Better Life
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• v.31 no.1
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• pp.11-27
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• 2013

The purpose of this study was to investigate the overall developmental characteristics of Korean children ages 0 to 8, and then explore specifically how children's social and emotional developmental levels are related to mothers' psychological states. This study was part of newly launched Boryung Baby Panel Study using web-based survey in 2011. The subjects were all mothers of 940 infants(0-2 years), 654 toddlers(3-5 years), and 484 school-age children(6-8 years) The mothers were asked to administer the web-based standardized developmental checklist for their child and fill out the questionnaires of psychological variables(life satisfaction, depression, parenting attitude, parenting efficacy, and parenting stress). The data was analyzed using descriptive analysis, t-test, and logistic regression for SPSS 20.0 windows. Major findings were as follows: 1. Infants(0 to 2) showed higher developmental level in cognition and fine motor skill domain compared to other domains. 2. Most toddlers(3 to 5) showed normal development in the most domain such as gross motor skill, fine motor skill, language, letter, number, self-help behavior. 3. In socio-emotional development domain, the ratio of risk or delay group were highest at both infant and toddler. 4. The 6-8 years old children that belong to risk group by the result of SDQ(emotion and behavior assessment) were also relatively high. 5. The relation of the children's socio-emotional developmental level and the mother's psychological variables were reciprocal. Based on these findings, the implications and the limitations of current study were discussed.

• Journal of the Korean Society of Food Culture
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• v.22 no.2
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• pp.235-245
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• 2007

This study was undertaken to develop web-based nutrition information contents for the older adults. Twenty six domestic web-sites were analyzed and then 12 foreign web-sites and 4 education materials for the elderly of foreign university were benchmarked. Also a lot of literatures on elderly education program were reviewed. A card-sorting task was performed with 8 older adults to ascertain how the target audience organized information about nutrition. The results were as fellows. Among 26 domestic web-sites, 2 sites(7.7%) were only for the elderly. Main topics of information contents for the elderly included 'Importance of Healthy Eating', 'DRI', 'Dietary Guidelines'. Four of twelve foreign web-sites were for the elderly nutrition education. Topics of 'Dietary Guideline', 'Meal Program' were found in 4 sites and 'Importance of Healthy Eating', 'Diet & Disease', 'DRI, 'Food Guide Pyramid', 'Nutrition Fact Labels' were found in 3 sites. Education materials of foreign university dealt with basic information on 'nutrient needs changes related with aging', 'Heart & Bone Healthy Eating Plan', 'Food Guide Pyramid'. Also topics on 'Eating on a budget', 'Eating Out Guideline' were included for practical use for the elderly. Based on card-sorting process, contents framework for web-site was developed and 4 main menus for framework were respectively named as 'Nutrition', 'Meals', 'Foods'. 'Check up Nutritional Health' by panel discussion. Finally we developed nutrition information contents for 4 main menus. We focused on helping older adults recognize the importance of healthy eating and apply the nutrition information to practical use. We expect that the developed framework of contents can be a guideline for indentifying the information needs of older adults in developing effective nutrition intervention program. And we suggest that the survey for target people should be peformed for the web-site to be user-friendly designed and the developed contents be evaluated and revised in the near future.

• Steel and Composite Structures
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• v.45 no.2
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• pp.159-173
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• 2022

This paper proposes a hybrid machine-learning model, which is called DANN-IP, that combines a deep artificial neural network (DANN) and an interior-point (IP) algorithm in order to improve the prediction capacity on the patch loading resistance of steel plate girders. For this purpose, 394 steel plate girders that were subjected to patch loading were tested in order to construct the DANN-IP model. Firstly, several DANN models were developed in order to establish the relationship between the patch loading resistance and the web panel length, the web height, the web thickness, the flange width, the flange thickness, the applied load length, the web yield strength, and the flange yield strength of steel plate girders. Accordingly, the best DANN model was chosen based on three performance indices, which included the R^2, RMSE, and a20-index. The IP algorithm was then adopted to optimize the weights and biases of the DANN model in order to establish the hybrid DANN-IP model. The results obtained from the proposed DANN-IP model were compared with of the results from the DANN model and the existing empirical formulas. The comparison showed that the proposed DANN-IP model achieved the best accuracy with an R^2 of 0.996, an RMSE of 23.260 kN, and an a20-index of 0.891. Finally, a Graphical User Interface (GUI) tool was developed in order to effectively use the proposed DANN-IP model for practical applications.

• Journal of the Korea Society of Computer and Information
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• v.28 no.10
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• pp.155-161
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• 2023

In this paper, we present a WebRTC-based emergency video call system structure that builds a service system in a constant monitoring environment to increase the usability and stability of elevator emergency call devices. The proposed system provides a smooth call environment between the emergency call system in the elevator and maintenance managers in case of an emergency, performs rapid response processing to elevator emergency calls through monitoring of the target elevator, and handles any emergency calls that may occur in the physical space of the elevator. The purpose is to build an environment that can implement low-latency, real-time video call services of voice and video by overcoming the physical constraints required for video calls. To this end, we have established a service environment based on OpenAPI, which is currently used in various fields and its performance has been proven, and provides video calls and emergency situation dissemination through rapid messaging by providing low-latency call quality. The presented system structure will be able to provide a basis for expanding various functions and constructing a reliable service environment and intelligent model for the elevator system through combination with the elevator control panel and various devices.