• Steel and Composite Structures
• /
• 제31권6호
• /
• pp.629-640
• /
• 2019

The investigation of retaining wall structures behavior under dynamic loads is considered as one of important parts for designing such structures. Generally, the performance of these structures is under the influence of the environment conditions and their geometry. The aim of this research is to design retaining wall structures based on smart and optimal systems. The use of accuracy and speed to assess the structures under different conditions is one of the important parts sought by designers. Therefore, optimal and smart systems are able to have better addressing these problems. Using numerical and coding methods, this research investigates the retaining wall structure design under different dynamic conditions. More than 9500 models were constructed and considered for modelling design. These designs include height and thickness of the wall, soil density, rock density, soil friction angle, and peak ground acceleration (PGA) variables. Accordingly, a neural network system was developed to establish an appropriate relationship between data to obtain safety factor (SF) of retaining walls under different seismic conditions. Different parameters were analyzed and the effect of each parameter was assessed separately. According to these analyses, the structure optimization was performed to increase the SF values. The optimal and smart design showed that under different PGA conditions, the structure performance can be appropriately improved while utilization of the initial (or basic) parameters leads to the structure failure. Therefore, by increasing accuracy and speed, smart methods could improve the retaining structure performance in controlling the wall failure. The intelligent design process of this study can be applied to some other civil engineering applications such as slope stability.

• 문화기술의 융합
• /
• 제6권3호
• /
• pp.437-442
• /
• 2020

인터넷이라는 혁신적인 정보기술의 도래 이후, 정보 환경의 다이너미즘(dynamism)은 정보 이용자들의 니즈 및 행태에 있어서의 변화를 초래하였다. 이러한 급변하는 환경의 정보 이용자들에 대한 이해는 필수적이며, 이를 기초해서 정보서비스와 이를 위한 시스템을 효과적으로 구축하여 운영할 필요가 있다. 본 연구의 목적은 과학기술정보서비스시스템 이용자의 세분화(segmentation)에 따른 특성을 이해하고 콘텐츠 이용실태 조사·분석을 통하여 맞춤형 서비스와 콘텐츠 개발에 대한 개선사항을 도출함에 있다. 총 816명의 과학기술정보서비스시스템 이용자들이, 지난 9월부터 11월까지, 온라인 설문조사에 참여하였다. 수집된 데이터는 요인 분석과 클러스터 분석 기법을 적용하여, 이용자를 세분화하고 새로운 정보기술과 정보서비스에 대한 인식, 과학기술정보 니즈, 그리고 이용자들이 중요하게 생각하는 과학기술 속성 등을, 세분화된 이용자그룹에 따른 결과를 도출하였다.

• 한국의상디자인학회지
• /
• 제16권4호
• /
• pp.1-14
• /
• 2014

In social commerce, consumers can buy products at much cheaper price if the required minimum number of buyers are made. Social commerce has showed rapid growth as an innovative distribution system receiving highlights, however it is true that it hasn't been sufficiently studied. The purpose of the study for presents the direction of growth of the fashion industry with social commerce through qualitative studies. This study is to make a preference group of four people and a non-preference group of four people of social commerce users for the fashion items sold social commerce market and lastly proposes some improvements. The 'preference group' showed high familiarity and preference to social commerce; and they had the tendency of the pursuit of convenience and voluptuous shopping. The revisit of 'non-preference group' preferred open market and, had the tendency of economical shopping and, they are favorable to other categories of social commerce. The reasons of preference were that accessibility was good in fashion products purchasing behaviors in social commerce and, it was convenient and, price was good and new information on cheap and good products were provided; the reasons of non-preference were that the quality of the products and genuineness of articles are doubtful or, the price is not the lowest or, the carried over products were majority. In the perspective of the fashion products in social commerce they answered that it would be brighter but improvements are needed such as supplying exact information, the lowest price, diversified products and the subdivision of category.

• Steel and Composite Structures
• /
• 제33권1호
• /
• pp.111-122
• /
• 2019

This paper presents an experimental work on the post-fire behavior of two kinds of innovative composite stub columns under eccentric compression. The partially precast steel reinforced concrete (PPSRC) column is composed of a precast outer-part cast using steel fiber reinforced reactive powder concrete (RPC) and a cast-in-place inner-part cast using conventional concrete. Based on the PPSRC column, the hollow precast steel reinforced concrete (HPSRC) column has a hollow column core. With the aim to investigate the post-fire performance of these composite columns, six stub column specimens, including three HPSRC stub columns and three PPSRC stub columns, were exposed to the ISO834 standard fire. Then, the cooling specimens and a control specimen unexposed to fire were eccentrically loaded to explore the residual capacity. The test parameters include the section shape, concrete strength of inner-part, eccentricity ratio and heating time. The test results indicated that the precast RPC shell could effectively confine the steel shape and longitudinal reinforcements after fire, and the PPSRC stub columns experienced lower core temperature in fire and exhibited higher post-fire residual strength as compared with the HPSRC stub columns due to the insulating effect of core concrete. The residual capacity increased with the increasing of inner concrete strength and with the decreasing of heating time and load eccentricity. Based on the test results, a FEA model was established to simulate the temperature field of test specimens, and the predicted results agreed well with the test results.

• 소성∙가공
• /
• 제25권6호
• /
• pp.379-389
• /
• 2016

As a stator for steam turbine diaphragm, hollow-type nozzle stator to substitute for conventional solid one is introduced in this study. This hollowed stator can be separated into two parts such as upper and lower plates with large and curved surface area. This study focuses on thick plate forming process for the upper plate of the hollow-partitioned nozzle stator. First, to reduce forming defects such as under-cut and localized thinning of the deformed plate, and to avoid tool interruption between forming punch and lower die, tool design including the position determination of forming surfaces is performed. Uni-axial tensile tests are carried out using SUS409L steel plate with initial thickness of 5.00mm, and plastic strain ratio (r-value) is also obtained. Due to the asymmetric curved configuration of the upper plate, it is hard to adopt a series of blank holder or draw-bead, so the initial plate during this thick plate forming experiences unstable and non-uniform contact. To easy this forming difficulty and find suitable tool geometry without sliding behavior of the workpiece in the die cavity, two geometric parameters with respect to each shoulder angle of the lower die and the upper punch are adopted. FE models with consideration of 21 combinations for the geometric parameters are built-up, and numerical simulations are performed. From the simulated and predicted results, it is shown that the geometric parameter combinations with ($30^{\circ}$, $90^{\circ}$) and ($45^{\circ}$, $90^{\circ}$) for the shoulder angle of the lower die and the upper punch are suitably applied to this upper plate forming of the hollow-partitioned nozzle stator used for the turbine diaphragm.

• 한국엔터테인먼트산업학회논문지
• /
• 제8권2호
• /
• pp.283-297
• /
• 2014

미래 인간의 삶은 사회, 경제, 정치와 개인 등 삶의 전 영역에 걸쳐 다학제적 기술의 파급효과 증대에 의해 혁신될 것이다. 특히 로봇 분야와 로봇을 이용한 차세대 게임 분야에서는 다학제적 기여와 상호작용에 의해 더욱 더 기술간 융합화가 가속화 될 것으로 전망된다. 본 연구는 지금까지의 "인간-로봇 인터페이스 기술"의 기술적인 한계 및 시공간적 제약을 뛰어넘는 새로운 인터페이스 모델로, 기존 인간-로봇 인터페이스 기술에서 가질 수 없는 다양한 모달리티(modality)들의 융합을 통해 보다 신뢰성 있으며 편하고 자유로운 "인간-로봇 인터페이스 기술"의 연구이다. 이족보행의 휴먼로봇과 모바일 기기 화면의 3D 콘텐츠(contents) 로봇(가상로봇)의 동작과 위치 값을 실시간적으로 연동하는 동기화(Synchronization) 엔진을 개발하고, 상호간의 정보를 주고받기 위한 무선 프로토콜(Protocol) 및 효율적인 티칭(Teaching)을 위한 학습에 의한, 다이렉트 티칭앤플레이(Direct Teaching & Play)의 티칭 프로그램 개발과, 이를 이용한 로봇 게임 시스템을 연구한다.

• 한국의류학회지
• /
• 제12권3호
• /
• pp.309-318
• /
• 1988

The purposes of this study were: 1) to develop specific AIO variables(clothing variables) based on clothing behavior studies, 2) to segment apparel market by clothing variables, 3) to discribe the profile of each segment with clothing variables, lifestyle variables and demographic variables, 4) to Suggest effective strategies on apparel market of women's clothing. The Likert Type clothing questionnaires measured 6 aspects of clothing (fashion, conformity-individuality, practicality, aesthetics, modesty and brand consciousness & status symbols) dealing with activities, interests and opinions. In addition, lifestyle variables were measured with general AIO statements. The questionnaires were administered to 563 young women (students, career women and homemakers) living in Seoul. The data were analysed by factor analysis, ctustering analysis, multiple discriminant analysis, one-way ANOVA ana Duncan's multiple range test. The results of the study were as follow: 1) 4 factors emerged from factor analysis of clothing variables. Factor 1: lower interest in modesty and higher interest in aesthics, Factor 2: brand consciousness and status symbols, Factor 3: conformity, Factor4 : fashion. 2) Lifestyle variables clustered into 3 factors. Factor 1: positive social activity, Factor 2: family-oriented type, Factor S: materialism. 3) By cluster analysis of the 4 factors of the clothing variables, the apparel market of women's clothing was categorised into 3 segments (innovative aesthetics seeker group, brand and status symbols conscious group, clothing unconscious group). 4) The above three segmented groups were also significantly discriminated by lifestyle and demosraphic variables. 5) On the basis of the findings, effective marketing strategies of women's clothing were suggested.

• Structural Monitoring and Maintenance
• /
• 제5권2호
• /
• pp.205-229
• /
• 2018

Energy induced by minor earthquake and micro vibration cannot be dissipated by traditional buckling-restrained braces (BRBs). To solve this problem, a new type of hybrid passive control device, named as VE-BRB, which is configured by a BRB with high-damping viscoelastic (VE) layers, is developed and studied. Theoretical analysis, performance tests, numerical simulation and case analysis are conducted to study the seismic behavior of VE-BRBs. The results indicate that the combination of hysteretic and damping devices lead to a multi-phased nature and good performance. VE-BRB's working state can be divided into three phases: before yielding of the steel core, VE layers provide sufficient damping ratio to mitigate minor vibrations; after yielding of the steel core, the steel's hysteretic deformations provide supplemental dissipative capacity for structures; after rupture of the steel core, VE layers are still able to work normally and provide multiple security assurance for structures. The simulation results agreed well with the experimental results, validating the finite element analysis method, constitutive models and the identified parameters. The comparison of the time history analysis on a 6-story frame with VE-BRBs and BRBs verified the advantages of VE-BRB for seismic protection of structures compared with traditional BRB. In general, VE-BRB had the potential to provide better control effect on structural displacement and shear in all stages than BRB as expected.

• Smart Structures and Systems
• /
• 제26권1호
• /
• pp.89-102
• /
• 2020

Shape memory alloy (SMA)-based Superelasticity-assisted Slider (SSS) is proposed as an engineering solution to practically exploit the well-accepted advantages of both sliding isolation and SMA-based recentering. Self-centering capability in SSS is provided by austenitic SMA cables (or wire ropes), recently attracting a lot of interest and attention in earthquake engineering and seismic isolation. The cables are arranged in various novel and conventional configurations to make SSS versatile for aseismic design and retrofit of structures. All the configurations are detailed with thorough technical drawings. It is shown that SSS is applicable without the need for Isolation Units (IUs). IUs, at the same time, are devised for industrialized applications. The proof-of-concept study is carried out through the examination of mechanical behavior in all the alternative configurations. Force-displacement relations are determined. Isolation capabilities are predicted based on the decreases in seismic demands, estimated by the increases in effective periods and equivalent damping ratios. Restoring forces normalized relative to resisting forces are assessed as the criteria for self-centering capabilities. Lengths of SMA cables required in each configuration are calculated to assess the cost and practicality. Practical implementation is realized by setting up a small-scale IU. The effectiveness of SSS under seismic actions is evaluated using an innovative computer model and compared to those of well-known Isolation Systems (ISs) protecting a reference building. Comparisons show that SSS seems to be an effective IS and suitable for earthquake protection of both structural and non-structural elements. Further research aimed at additional validation of the system are outlined.

• 한국건설관리학회논문집
• /
• 제5권3호
• /
• pp.71-78
• /
• 2004

In conventional method of supporting soil shuttering wall during excavation a system of struts and wales to provide cross-lot bracing is common in trench excavations and other excavations of limited width. This method, however, becomes difficult and costly to be adopted for large excavations since heavily braced structural systems are required. Another expensive and unsafe situations are expected when temporary struts must be removed for the construction of underground structures. This paper introduces innovative strut systems which can be used as permanent underground structures after its role as brace system to resist earth pressure during excavation phase. Underground structural system suggested from architect is checked against the soil lated pressures before the analysis of stresses developed from gravity loads. In this technology, named SPS(Struts as Permanent System), retaining wall is installed first and excavation proceeds until the first level of bracing is reached. Braces used as struts during excavation will serve as permanent girders when buildings are in operation. Simultaneous construction of underground and superstructure can proceeds when excavation ends with the last level of braces being installed. In this paper, construction sequence and the calculation concept are explained in detail with some photo illustrations. SPS technology was applied to three selected buildings. One of them was completed and two others are being constructed Many sensors were installed to monitor the behavior of retaining wall, braces as column in terms of stress change and displacement. Adjacent ground movement was also obtained. These projects demonstrate that SPS technology contributes to the speed as well as the economy involved in construction.