• Steel and Composite Structures
• /
• 제18권2호
• /
• pp.325-344
• /
• 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.

• 융합보안논문지
• /
• 제23권5호
• /
• pp.101-106
• /
• 2023

최근 사이버 공격은 지능적이고 지속적인 피싱사이트와 악성코드를 활용한 해킹 기법을 활용하는 사회공학적 공격이 증가하고 있다. 개인 보안이 중요해지는 만큼 웹 어플리케이션을 이용해 악성 URL 여부를 판별하는 방법과 솔루션이 요구되고 있다. 본 논문은 악성 URL를 탐지하는 정확도가 높은 기법들을 비교하여 각각의 특징과 한계를 알아가고자 한다. 웹 평판 DB 등 기반 URL 탐지 사이트와 특징을 활용한 분류알고리즘 모델과 비교하여 효율적인 URL 이상탐지 기법을 제안하고자 한다.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2001년도 가을 학술발표회 논문집
• /
• pp.227-234
• /
• 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.

• 산학경영연구
• /
• 제15권
• /
• pp.79-97
• /
• 2002

본 연구에서는 고객 세분화를 위하여 고객프로필과 사이트 접속자료를 통합, 분석하는 분석적 CRM을 시도하였다. 실제 고객 데이터를 분석하여 고객의 특성과 기호, 방문행태 등을 이해할 수 있다면 이를 기반으로 고객 세분화(segmentation)가 가능할 것이다. 예를 들어 고객의 거주지, 재산정도, 교육수준, 연령 등 인적정보를 토대로 동일 사이트에 접속하는 고객의 공통점을 찾게 된다면 이들 고객에 접근할 수 있는 적절한 마케팅 미디어가 무엇인지, 어느 페이지에 홍보물을 게재하는 것이 효과적일 것인가 등을 결정하는 데 도움을 줄 수 있을 것이다. 한편 웹 기반 마이닝의 핵심은 웹으로 부터의 자료를 어떻게 하면 효율적으로 수집할 것인가, 또한 이렇게 수집된 자료를 다양한 (multiple) DB와 어떻게 통합하고 분석하여 필요한 정보를 추출할 것인가 일 것이다. 본 연구에서는 실제 인터넷 사업자의 사용자 그룹의 비율에 따라 구성된 패널을 활용하여 효율적인 자료수집 방안을 모색하였다. 패널 구성원에 대한 웹 데이터를 수집함으로써 신뢰성과 대표성을 확보하면서 분석대상 자료의 양을 적절한 수준으로 유지할 수 있었다. 또한 고객자료 분석에서는 OLAP과 데이터 마이닝 기법(의사결정나무)을 동시에 사용하여 그 분석 결과를 비교함으로써 각 기법의 결과를 상호 확인하고 보완할 수 있었다. 이 결과는 데이터 마이닝 기법에 의해서 발견된 패턴을 분석하고 확인하는 작업에서 OLAP이 유용하게 사용될 수 있다는 과거 연구의 주장을 확인하였다.

• 대한조선학회논문집
• /
• 제43권3호
• /
• pp.392-398
• /
• 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
• /
• 제5권3호
• /
• pp.348-363
• /
• 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.

• 가정과삶의질연구
• /
• 제31권1호
• /
• pp.11-27
• /
• 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.

• 한국식생활문화학회지
• /
• 제22권2호
• /
• pp.235-245
• /
• 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
• /
• 제45권2호
• /
• pp.159-173
• /
• 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.

• 한국컴퓨터정보학회논문지
• /
• 제28권10호
• /
• pp.155-161
• /
• 2023

본 논문에서는 승강기 비상통화 장치의 활용성과 안정성을 높이기 위해 상시 모니터링 환경의 서비스 체계를 구축하는 WebRTC 기반의 비상 화상통화 시스템 구조를 제시한다. 제시된 시스템은 비상상황 시 승강기 내의 비상 호출 시스템과 유지보수 담당자들 간의 원활한 통화 환경을 제공하고 대상 승강기의 모니터링을 통해 승강기 비상 호출에 대한 신속한 응답 처리를 수행하고 승강기의 물리적 공간에서 발생할 수 있는 화상통화에 필요한 제약환경을 극복하여 음성과 영상의 저지연 실시간 화상통화 서비스를 구현할 수 있는 환경을 구축하고자 한다. 이를 위해 현재 다양한 분야에서 활용되고 그 성능이 검증된 OpenAPI를 기반으로 서비스 환경을 구축하고 실시간 화상통화 및 저지연 통화 품질 제공, 그리고 신속한 메시징 방식의 비상상황 전파 방식을 통해 비상 화상통화 장치의 성능 및 활용성을 높이고자 한다. 제시된 시스템 구조는 승강기 제어반 및 다양한 장치와의 결합을 통해 다양한 기능 확장 및 신뢰성 있는 서비스 환경을 통해 승강기 시스템에 대한 지능적 모델을 구성할 수 있는 기반을 제공할 수 있을 것이다.