• Structural Engineering and Mechanics
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• 제58권6호
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• pp.1045-1075
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• 2016

Shallow footings are one of the most common types of foundations used to support mid-rise buildings in high risk seismic zones. Recent findings have revealed that the dynamic interaction between the soil, foundation, and the superstructure can influence the seismic response of the building during earthquakes. Accordingly, the properties of a foundation can alter the dynamic characteristics (natural frequency and damping) of the soil-foundation-structure system. In this paper the influence that shallow foundations have on the seismic response of a mid-rise moment resisting building is investigated. For this purpose, a fifteen storey moment resisting frame sitting on shallow footings with different sizes was simulated numerically using ABAQUS software. By adopting a direct calculation method, the numerical model can perform a fully nonlinear time history dynamic analysis to realistically simulate the dynamic behaviour of soil, foundation, and structure under seismic excitations. This three-dimensional numerical model accounts for the nonlinear behaviour of the soil medium and structural elements. Infinite boundary conditions were assigned to the numerical model to simulate free field boundaries, and appropriate contact elements capable of modelling sliding and separation between the foundation and soil elements are also considered. The influence of foundation size on the natural frequency of the system and structural response spectrum was also studied. The numerical results for cases of soil-foundation-structure systems with different sized foundations and fixed base conditions (excluding soil-foundation-structure interaction) in terms of lateral deformations, inter-storey drifts, rocking, and shear force distribution of the structure were then compared. Due to natural period lengthening, there was a significant reduction in the base shears when the size of the foundation was reduced. It was concluded that the size of a shallow foundation influences the dynamic characteristics and the seismic response of the building due to interaction between the soil, foundation, and structure, and therefore design engineer should carefully consider these parameters in order to ensure a safe and cost effective seismic design.

• Structural Engineering and Mechanics
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• 제76권1호
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• pp.83-99
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• 2020

Shear walls are structural members in buildings that are used extensively in reinforced concrete frame buildings, and almost exclusively in the UK, regardless of whether or not they are actually required. In recent years, the UK construction industry, led by the Concrete Centre, has questioned the need for such structural elements in low to mid-rise reinforced concrete frame buildings. In this context, a typical modern, 5-storey residential building is studied, and its existing shear walls are replaced with columns as used elsewhere in the building. The aim is to investigate the impact of several design variables, including concrete grade, column size, column shape and slab thickness, on the building's structural performance, considering two punching shear limits (V_Ed/V_Rd,c), lateral drift and accelerations, to evaluate its maximum possible height under wind actions without the inclusion of shear walls. To facilitate this study, a numerical model has been developed using the ETABS software. The results demonstrate that the building examined does not require shear walls in the design and has no lateral displacement or acceleration issues. In fact, with further analysis, it is shown that a similar building could be constructed up to 13 and 16 storeys high for 2 and 2.5 punching shear ratios (V_Ed/V_Rd,c), respectively, with adequate serviceability and strength, without the need for shear walls, albeit with thicker columns.

• 한국시뮬레이션학회논문지
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• 제23권2호
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• pp.17-24
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• 2014

본 논문은 항공기용 EHA의 열유동 해석모델을 개발하고 활용하는 사례를 보여준다. 연구진행 절차는 다음과 같다. 첫째, 설계 컨셉에 맞는 물리량을 반영하는 유압단품 해석모델을 개발한다. 둘째, 유압단품 모델을 조합하여 EHA 유압모델로 확장한다. 셋째, 열유동이 포함된 해석모델을 개발하여 초기온도와 부하의 변화에 따른 유온의 상승시간을 검토한다. 마지막으로, 여러 케이스의 열유동 해석결과가 조합된, 설계에 활용이 가능한 지배그래프를 작성하여 제안한다. 이 모든 과정은 상용 소프트웨어인 AMEsim을 사용하여 진행한다.

• 대한전자공학회논문지TC
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• 제44권7호통권361호
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• pp.70-80
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• 2007

차세대 이동 네트워크에서는 다양한 무선 접속 기술이 공존하게 된다. 이에 따라, 다양한 무선망에서 QoS를 지원하는 분산 방식의 호 수락 제어 구조인 SmartCAC를 제안한다. 본 논문은 네트워크간 정보 수집이 필요없는 분산방식을 위하여 모바일 노드와 네트워크간의 상호동작을 이용한다. SmartCAC는 기본적으로 VHO 호와 새로운 호1의 구분이 가능하도록 함으로써 VHO 호에 핸드오프를 위해 예약된 채널을 사용할 수 있도록 한다. 또한, 효율적인 호 수락 제어를 위하여 QoS 요구와 네트워크 사용에 대한 delay와 reliability를 다룬다. 뿐만 아니라, 이종망에서 네트워크 필터링을 할 수 있도록 모바일노드의 스피드를 이용한다. 이종망의 상태정보를 알 수 없는 모바일노드가 네트워크의 상태정보를 받아 비교할 수 있도록 확장된 프로토콜을 제시하고, 시뮬레이션 연구에서 기존의 CAC 방식과 제어메시지에 의한 비용을 비교하여 37%에서 96%까지 향상되는 효과를 입증한다.

• Safety and Health at Work
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• 제8권1호
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• pp.94-98
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• 2017

Background: Physical activity (PA) is ranked as a leading health indicator and the workplace is a key setting to promote PA. The purpose of this study was to examine how goal-setting and exercise self-efficacy (SE) during a health promotion program influenced PA level among Japanese workers. Methods: Using a cross-sectional study design, we surveyed 281 employees. The short version of the International Physical Activity Questionnaire was used to assess PA level. Exercise SE was assessed using a partially modified version of Oka's exercise SE scale. Personal goals were assessed as the total numbers of "yes" responses to five items regarding "details of personal goals to perform PA". A mediational model was used to examine whether exercise SE mediates between the number of personal goals and PA level. Results: The mean age of the participants was 46.3 years, 76.2% were men, and the most common occupational category was software engineer (30.6%). The average PA level per week exceeded the recommended level in 127 participants (45.2%). One hundred and eighty-four participants (65.5%) set some form of concrete personal goal to perform PA. The relationship between the number of personal goals and PA level was mediated by exercise SE. Conclusion: Our study showed that exercise SE mediates goal-setting and increases PA. The results suggest that the components of PA promotion programs should be tailored to enhance participants' confidence in performing PA.

• 한국통신학회논문지
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• 제37C권10호
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• pp.933-939
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• 2012

일반적으로 선박공정에서 작업자는 완성된 블록을 레이저 계측장비를 이용하여 제작된 선박블록의 3차원 좌표를 측정한다. 그런데 제작된 선박블록의 좌표측정은 수작업으로 이루어졌으므로 이에 의한 측정된 좌표는 설계단계에서 작성된 도면의 설계좌표와 편차가 발생한다. 이로 인해 작업자는 육안으로 직접 선박블록의 측정좌표와 설계좌표의 일치정도를 확인해야 하며, 이는 선박불록의 정도관리에 대한 인적 및 시간적 비용을 크게 증가시킨다. 본 논문에서는 선박공정의 선박블록의 정도관리에 있어서 이러한 단점을 해결할 수 있는 자동화된 3차원 좌표의 패턴매칭 알고리즘을 제안하고, 제안한 3차원 좌표의 패턴매칭 알고리즘의 성능은 자체적으로 개발한 3차원 좌표 시뮬레이션 프로그램에 의해 분석하였다. 단일 및 다수 선박블록의 측정좌표 데이터에 대한 좌표매칭율은 거리오차 허용범위가 20~25cm에서 약 90.2%가 됨을 확인하였다.

• 공학교육연구
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• 제21권3호
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• pp.56-65
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• 2018

With rapid advance of technologies including information and communication technologies, jobs are evolving faster than ever. Architectural engineering is no exception in this regard, and the green architectural engineering is emerging fast as a promising new field. In this study, a Delphi study of expert architectural engineers are conducted to find out (1) near future prospects of the field, (2) near future emerging jobs, (3) competencies needed for these jobs, and (4) educational content necessary to build these competencies with regards to the green architectural engineering. Initial Delphi survey consisting of open-ended questions in the above four areas were conducted and came out with 65 items after duplicate removal and semantic refinements. Further refinements via second and third wave of Delphi results into 40 items that the 13 architectural engineering experts may largely agree upon as future prospects with regards to the green architectural engineering. Findings indicate that it is expected that the demand for green architectural engineering and needs for automatic energy control system increase. Also, collaborations with other fields is becoming more and more important in green architectural engineering. The professional work management skills such as knowledge convergence, problem solving, collaboration skills, and creativity linking components from various related areas seem to also be on the increasing need. Near future ready critical skills are found to be the building environment control techniques (thermal, light, sound, and air), the data processing techniques like data mining, energy monitoring, and the control and utilization of environmental analysis software. Experts also agree on new curriculum for green building architecture to be developed with more of converging subjects across disciplines for future ready professional skills and experiences. Major topics to be covered in the near future includes building environment studies, building energy management, energy reduction systems, indoor air quality, global environment and natural phenomena, and machinery and electrical facility. Architectural engineering community should be concerned with building up the competencies identified in this Delphi preparing for fast advancing future.

• International Journal of Computer Science & Network Security
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• 제22권7호
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• pp.443-450
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• 2022

The method of studying 3D-technologies abroad and in Ukraine is considered. The analysis of educational resources and experience of use of the equipment in branch is carried out. The didactic principles of the educational process for 3D-printing specialists are determined. The use of FDM technology and the ability to minimize the occurrence of defects in the future have been studied. An analysis of the international experience of the educational process of relevant specialists in the field. The content of training for 3D printing specialists has been developed. The experience of using 3D-technologies is described and the list of recommendations for elimination of defects during production of products by means of additive technologies is made. The recommendations will be useful not only for beginners, but also for experienced professionals in additive technologies. The need to study such experience is the main condition for the development of enterprises in Ukraine that plan to automate their own production. A 3D printing engineer must know the basics of economics and marketing, because his responsibilities include optimizing workflows to reduce the cost and speed up printing. Therefore, the knowledge gained from practical experience presented and in building for learning 3D printing engineers by the authors will be important.

• 한국인터넷방송통신학회논문지
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• 제23권1호
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• pp.1-6
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• 2023

언캐니 밸리는 일본의 로봇 공학자 모리 마사히로가 1970년 제안한 이론으로 로봇이 완전히 갖추어지지 않은 상태에서 외형이 인간과 매우 흡사해질 때 호감도가 급격하게 떨어지는 지점을 가리킨다. 본 연구에서는 기존 문헌들의 이론과 선행 연구된 관련 논문 그리고 실험 자료를 분석하여 캐릭터 디자인에 영향을 미치는 언캐니 밸리 효과에 대해 고찰하였으며 본 연구의 목적은 로봇 분야에서 연구된 언캐니 밸리 효과가 언리얼 엔진의 마켓플레이스에서 유통되고 있는 가상 캐릭터의 모델링에도 적용되는지 분석하기 위함이다. 이를 위해 언리얼 엔진의 마켓플레이스에서 인간과의 유사도를 기준으로 15가지 캐릭터를 선정하여 인간과의 유사도와 호감도에 대해 조사 및 분석하였다. 실험 결과 가상 캐릭터 모델링에도 언캐니 밸리 효과가 유사하게 적용되고 있음을 확인하였고 이를 통해 언리얼 엔진을 사용하는 인디 게임 개발자나 개인 개발자의 캐릭터 활용을 위한 가이드라인을 제시하고자 하였다. 또한 결과 분석을 통해 캐릭터 디자인 시 추구해야 할 방향에 대해 살펴보고자 하였다.

• 한국해안·해양공학회논문집
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• 제28권5호
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• pp.277-283
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• 2016

테트라포드는 경사식 방파제의 피복재로 가장 많이 사용되는 콘크리트 소파블록이다. 테트라포드의 안정수를 계산하는 것은 테트라포드의 적정 중량을 결정하기 위해 필요한 과정이다. 1950년대의 Hudson 식부터 최근에 Suh and Kang이 제안한 식까지 테트라포드의 안정수를 계산하기 위한 다양한 경험식들이 제안되었다. 이러한 경험식들은 대부분이 식의 형태를 가정하고 실험 자료를 이용하여 식의 계수들을 회귀분석을 통해 결정하였다. 최근에는, 실험 데이터가 많은 경우, software engineering (또는 machine learning) 방법이 도입되고 있다. 예를 들어서, 방파제 피복석의 안정수를 계산하기 위한 인공신경망 모델이 제안된 바 있다. 그러나 이러한 방법들은 기존의 경험식보다 정확도가 크게 뛰어나지 않고 엔지니어들에게 생소하기 때문에 아직까지 설계에 거의 사용되지 않고 있다. 본 연구에서는 인공신경망 모델의 가중치와 편의를 이용하여 테트라포드의 안정수를 계산하는 양해법을 제안한다. 이 방법은 행렬 연산을 할 줄 아는 엔지니어라면 인공신경망에 대한 지식이 없어도 사용할 수 있으며, 기존의 경험식에 비해 정확도도 우수하다.