• 한국건축시공학회지
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• 제12권3호
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• pp.299-314
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• 2012

One of reasons for introducing Building Information Modeling (BIM) is to support clash detection tasks by means of a 3D product model. In the conventional construction project process, clashes have been found during construction phase. However, it can cause cost overrun and time delay. In order to investigate and correct clash detections at design phase, relevant business process and guide for this task should be provided. This study aims to identify hindrances in clash detection tasks at the design phase and analyze its current process using IDEF0 model. Despite the convenience of IDEF0 as a systems analysis tool, professional participants might have difficulties to understand their own tasks according to business process. For this reason, in this research, Business Process Model and Notation (BPMN) is introduced to provide ideal process and required decision making governance. The provide BPMN model will provide insights for a BIM-based collaborative environment to enhance the constructability through the construction project.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.12-16
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• 2011

Building Information Modeling (BIM) is being widely spread in AEC industry worldwide and also in South Korea. Although the creation of digital model is better to be started at design stage, it can also improve the productivity of construction by simulating the actual construction process and environment. This paper presents application of BIM-based simulations related with design changes to transfer floors in 58-storey reinforced concrete office building. Transfer floor is not only a structurally important part of the building but also a challenging part of the actual construction in terms of sequence and period due to the complexity of the work. Preconstruction of rebar, mechanical, and plumbing is performed to review the construction drawings and to perform clash detection. Each item of application is evaluated for its effectiveness on actual construction and for the development potential.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.634-639
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• 2013

The aim of the study is to develop the 3D visualization of Building Information Model and integrated 4D model for optimization of resources in the construction project. This study discuss the process of methodology and creation of 4D model of the project and simulate it to monitor the workflow at the site. Different stages of the construction process and activities are generated by using Revit and MS Project. MS project has been used for creation of the schedules and these are linked with the Revit for 3D modeling. The time used as the fourth dimension and 4D model created by using Navisworks Time liner software. Narges shopping center is presented as a case study to realize the actual uses and benefits of Building Information Model (BIM). Narges shopping mall is located in Tehran, Iran. As a part of Hekmat master plan, Narges shopping center is an 11 stores building with a total area of 30000 Sq.m. This shopping and entertainment center is comprised of 150 retails and two multi-use public halls with a capacity of 400 persons each and underground parking with total 400 parking space. The main purpose of architecture was to create an urban public center along with its revolving, spiral like form and an ever changing continuous façade by means of different colors, materials, which is in harmony with the other building of the master plan. The approximate cost of the project is $17 million and duration of the project schedule is 30 months. The developed Building Information Model enabled us to identify the potential collisions or clashes between various structural and architectural systems. 4D model has been used for limiting the interaction between subcontractors installing the different systems so rework could be avoided and productivity maximized. It is also observed that the utility of BIM for construction stimulation and clash detection is the best suitable method. Clash detection before the implementation of work is highly recommended to avoid rework.

• 한국BIM학회 논문집
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• 제4권1호
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• pp.1-7
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• 2014

The construction method using PC(Precast Concrete) has been widely used because the method can shorten the construction period and improve construction quality. In this paper, through the analysis of present design process for PC railway platform, design parameters on the geometry and properties were extracted and 3D information models for PC railway platform were constructed by the parametric modeling technique. Furthermore, the interface module was developed to link 3D models to the structural analysis/design sheet and database program using VBA(Visual Basic Application). This information model could be used in various areas including structural analysis and design, 2D drawing, quantity estimation and 4D simulation including clash detection.

• 한국건축시공학회지
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• 제12권1호
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• pp.98-107
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• 2012

Reinforcing bars (rebar) comprise an integral part of a concrete structure, and play a major role in the safety and durability of the building. However, the actual placement or installation of rebar is not planned and controlled by the detailer. Recently, 4D simulations, using 3D model and scheduling software, have been used to improve the efficiency of the construction phrase. However, 4D simulators have not been introduced at the detailed level of work, such as rebar placement. Therefore, this paper suggests a BIM-based simulator for rebar placement to determine the sequence with which rebar is placed into the form. The system using Autodesk Revit API automatically generates rebar placement plans for a building structure, and labels the placement sequence of each individual bar or set of bars with ascending numbers. The placement sequence is then visualized using Autodesk Revit Structure 2012. This paper provides a short description of a field assessment and limits.

• 전력전자학회논문지
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• 제13권4호
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• pp.278-286
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• 2008

본 논문은 대용량 더블컨버젼 방식 $30^{\sim}500[KVA]$ 무정전전원공급장치 UPS(Uninterruptible Power Supply)의 고장발생유형과 출력정지현상의 원인을 살펴보고, 부하 측면에서 전원공급의 신뢰성을 높일 수 있는 고장 검출방식을 제안한다. 인버터 출력의 전원품질을 검출하여 이상으로 판단 시 바이패스 시키는 방식의 기존 UPS 제어방식의 경우, 만일 내부(전력변환소자, 컨트롤러, CPU)소손이 발생되는 경우에는 부하전원 공급이 중단되는 현상이 발생되었고 이를 실험파형과 장비 운용결과를 통하여 증명하였다. 본 논문은 이러한 사고의 경우에도 출력전원의 공급에는 문제가 없도록 하기 위하여 기존 UPS의 제어시스템과는 별도로 독립적으로 고장검출장치, 바이패스 제어장치, 3중전원공급장치를 구축한 상태에서, 고장검출위치를 최종출력스위치 전단으로 변경하고, 고장판단 기준값을 기존 UPS제어시스템과 충돌이 없도록 변경하고, 사고확산을 차단할 수 있는 장치를 하였다. 이 시스템을 통신전원공급용 UPS 242대에 적용한 결과 2006년 이후 2년간 서비스장애가 발생되지 않았다.

• 한국BIM학회 논문집
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• 제3권3호
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• pp.29-38
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• 2013

Domestic construction industry is larger in size, and its shape is more complex. As a result, collaboration and information management tasks are difficult to manage in a way that conventional 2D-based exchange of information. BIM technology was introduced as a solution for this. But BIM only provides a very limited set of features such as Constructability review, clash detection in reality. and duplication of work and a lot of iterations occurs in BIM process. Thus, it takes quite a lot time to work. We studied how to improve the work efficiency by connecting API to business processes. Using the API in the integration process by automating repetitive tasks, reduce a significant amount of work time Using API (Automation, Optimization, Interoperability, Analysis) can solve the task problem that does not solved by the basic features, If we make good use of the combined API will be improved productivity.

• International Journal of Safety
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• 제9권2호
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• pp.29-34
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• 2010

When doing maintenance works at the trackside of railway, the method which delivers information on approaching of train to maintenance workers through alarm devices such as the flag or indication light, etc., is being used by locating persons in charge of safety alarm in addition to the maintenance workers at fixed distances in the front and rear of the workplace. Workers maintaining at the trackside may collide with the train since they cannot recognize the approach of train although it approaches to the vicinity of maintenance workplace because of the sensory block phenomenon occurred due to their long hours of continued monotonous maintenance work. The clash or rear-end collision accidents between many maintenance trains called motor-cars can be occurred since there are cases where the signal systems for safe operation of motor-car such as track circuit etc. are blocked or not operated normally. We developed the new safety equipment for protection of trackside maintenance workers using radio frequency signals and bidirectional detection mechanism. The developed safety equipment must analyze the several operational mechanism for each different operation situations. In this paper the analysis results are represented.

• 인터넷정보학회논문지
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• 제21권4호
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• pp.117-126
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• 2020

해상 객체 인식은 자율운항선박(MASS)의 지능형 보조 시스템으로써, 선장이 육안으로 해상 주변의 충돌 위험성이 있는 부유물을 확인하던 정보를 컴퓨터를 통해 자동으로 인식하여 사람이 확인하는 방법과 유사한 정확도로 인지하는 방법을 말한다. 선박 주변의 물체를 인식하는 방법으로 기존에는 레이더나 소나와 같은 장치로부터 수집된 정보를 통해 확인하였지만, 인공지능의 기술이 발달하면서 선박 지능형 CCTV를 통해 운항 항로에 있는 다양한 부유물을 인식하는 것이 가능하다. 하지만, 자율 선박의 다양한 요구사항과 복잡성 때문에 영상 데이터의 처리속도가 느려지게 된다면 원활한 서비스 지원은 물론 안전성도 보장할 수 없게 된다. 이러한 문제를 해결하고자 본 논문에서는 해상 객체를 검출하는 데 있어 영상 데이터의 연산량을 최소화하여 처리속도를 높이기 위한 연구를 진행하였다. 해상 객체 인식의 관심 영역을 확보하기 위해서는 일반적으로 수평선을 찾는데 기존 연구들은 허프 변환 알고리즘을 활용하지만 본 논문에서는 속도를 개선하기 위해 이진화 알고리즘을 최적화하여 실제 객체의 위치와 유사한 영역을 찾는 새로운 방법을 제안한다. 또한, 제안하는 방법의 유용성을 증명하기 위해 딥러닝 CNN을 활용하여 해상 객체 인식 시스템을 구현함으로써 알고리즘의 성능을 평가하였다. 제안하는 알고리즘은 기존 방법의 인식 정확도를 유지하면서 약 4배 이상의 빠른 성능을 얻을 수 있었다.

• Smart Structures and Systems
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• 제29권4호
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• pp.625-640
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• 2022

Maglev rail joints are vital components serving as connections between the adjacent F-type rail sections in maglev guideway. Damage to maglev rail joints such as bolt looseness may result in rough suspension gap fluctuation, failure of suspension control, and even sudden clash between the electromagnets and F-type rail. The condition monitoring of maglev rail joints is therefore highly desirable to maintain safe operation of maglev. In this connection, an online damage detection approach based on three-dimensional (3D) convolutional neural network (CNN) and time-frequency characterization is developed for simultaneous detection of multiple damage of maglev rail joints in this paper. The training and testing data used for condition evaluation of maglev rail joints consist of two months of acceleration recordings, which were acquired in-situ from different rail joints by an integrated online monitoring system during a maglev train running on a test line. Short-time Fourier transform (STFT) method is applied to transform the raw monitoring data into time-frequency spectrograms (TFS). Three CNN architectures, i.e., small-sized CNN (S-CNN), middle-sized CNN (M-CNN), and large-sized CNN (L-CNN), are configured for trial calculation and the M-CNN model with excellent prediction accuracy and high computational efficiency is finally optioned for multiple damage detection of maglev rail joints. Results show that the rail joints in three different conditions (bolt-looseness-caused rail step, misalignment-caused lateral dislocation, and normal condition) are successfully identified by the proposed approach, even when using data collected from rail joints from which no data were used in the CNN training. The capability of the proposed method is further examined by using the data collected after the loosed bolts have been replaced. In addition, by comparison with the results of CNN using frequency spectrum and traditional neural network using TFS, the proposed TFS-CNN framework is proven more accurate and robust for multiple damage detection of maglev rail joints.