• Journal of KIBIM
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• v.3 no.2
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• pp.1-9
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• 2013

Currently, various studies and applications related BIM based quantity take-off have been attempted, because of the accuracy of cost estimating and reliability by using the BIM model information in automatical calculation. Finishing works that have a large number of various types and materials need the higher accuracy and reliability on the BIM-based quantity take-off. Therefore, this study compared and analyzed 2D and 3D based quantity through Test-bed and determine the cause of the quantity difference. This verified the accuracy and efficiency in the BIM-based quantity take-off for finishing works. Also this study has been proposed opinions for calculating the exact BIM-based quantity take-off.

• Survey Research
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• v.5 no.1
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• pp.93-101
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• 2004

In business survey, cut-off sampling is usual, The contribution from cut-off part of the population is at least small in comparison with the remaining population. In this case, part of the target population is excluded from the selection and parameter estimations are only based on Take-all and Take-some stratum. It may be tempting not to use resources on enterprises that contribute little to the overall results of the survey. And this reduces the response burden for these small enterprises. But, the size of cut-off stratum has been increased as a way to manage reduced budgets. This leads to additional bias. In this study, the population have been separated as three stratum, cut -off, take-some, take-all, and we will estimate cut-off part using auxiliary variable.

• The Korean Journal of Zoology
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• v.39 no.2
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• pp.132-138
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• 1996

To learn how maximal locomotory speed of animals is defined in terms of hindlimb structure and muscle contractile function, take-off speed, hindlimb length, thigh muscle mass, shortening velocity and power of the sastrocnemius muscle were measured with one fast species, Rono nigromaculota and one relatively slowresponding species, Bombina orientalis. Take-off speed (m.sec-1) was greater in R. nigromoculata $(2.4\pm0.2SD, $ n: 14) than in the Bombino $(1.6\pm0.1SD, $ n=8). Stvle of the take-off response was a long-iump type in the Rano and a short-ranged hopping in the Bombing. Faster take-off capacity of the ranid frogs was supported by the longer hindlimb length (relative to body length) and the more massive thigh muscles (relative to body mass), compared to the Bombina. Further, the ranids exhibited faster maximal shortening velocity and Breater maximal power generateion than the Bombina [Vmax $(ML.sec-1)=11.79\pm1.69SD$ for the Runa and $9.74\pm1.27SD$ for the Bombina; Pmax $nW.kg-1)=222.42\pm42.42SD$ for the Rono and $169.03\pm34.52SD$ for the Bombinal. With more massive thigh muscles and greater mechanical power, the ranids would generate greater total power and thus higher energy release per unit time to muscle tissues for the burst take-off. As a consequence, biomechanical properties seen in the ranids seem to be more effective for frost take-off than in the Bombina.

• Journal of The Korean Digital Architecture Interior Association
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• v.1 no.1
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• pp.46-50
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• 2001

It is known that to automate the quantity take-off process enables you to increase the productivity best among the construction business field. However, the limitation of 2D(Two-dimension) CAD System prevented a cost-estimating system which makes the great effects on the quantity take-off process from being developed. This study aims that you can automate both the itemized statements and the quantity take-off process by using commercially available object-oriented CAD system. The commercially available CAD system today does not give us entire satisfaction. This study shows the deduction of the old boundaries of the object-oriented CAD system and the solution of those problems. And it also studied about the quantity take-off process and the automated cost-estimating system that can be used in the simple and plain repair-maintenance work such as the execution drawing which doesn't need the complicated drawings.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.4
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• pp.85-92
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• 2020

Applications for the unmanned aerial vehicle (UAV) have expanded enormously in recent years. Of all its various technologies, the UAV's ability to take off and land in a moving environment is particularly required for military or oceanic usage. In this study, we develop a novel leveling platform that allows the UAV to stably take off and land even on uneven terrains or in moving environments. The leveling platform is composed of an upper pad and a lower mobile base. The upper pad, from which the UAV can take off or land, is designed in the form of a 2 degrees of freedom (DOF) gimbal mechanism that generates the leveling function. The lower mobile base has a four-wheel drive structure that can be operated remotely. We evaluate the developed leveling platform by performing extensive experiments on both the horizontal terrain and the 5-degree ramped terrain, and confirm that the leveling platform successfully maintains the horizontal pose on both terrains. This allows the UAV to stably take off and land in moving environments.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.142-143
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• 2008

In the present work, high-speed video images of the ground take-off flight of a live butterfly were captured and their dynamic motions during the first full-stroke were analyzed. To capture the dynamic images of the take-off motion, the experimental setup consisted of a high-speed camera, a Xenon lamp as a light source and a transparent chamber of $15^W{\times}15^L{\times}17^H$ $cm^3$ in physical size. The ambient temperature and supplementary lighting devices were precisely controlled. The weight and wing span of the butterfly tested in this study was 104 mg and 63.14 mm, respectively. The ground take-off images were captured with 4000 fps with a spatial resolution of (1024${\times}$512) pixels. The period of the first full-stroke was 80.5ms and the flapping speed of downstroke was 2 times faster than that of upstroke. As a result, butterflies used the fling and near-clap motion to generate lifting force and an interesting take-off behavior of early pronation and downstroke was observed.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.263-267
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• 2015

Stakeholders of a construction project expect cost savings through fast and accurate cost analysis by performing BIM-based quantity take-off (BQT). However, authors have observed that there can be discrepancies in the results of BQT depending on the level of development (LOD) and modeling methods. In addition, since quantity take-off methods are different depending on the construction work items, the combination of LOD, modeling methods of BIM, features of construction work items can cause serious overestimate or underestimate in BQT results. It is necessary to identify what kind of problems can happen and how those problems can be avoided in various construction work items, since the discrepancy of quantity take-off results has great impact on not only cost analysis but also the determination of contract amount and it can cause claims, poor construction quality, cost overruns, and many others later in the construction project. Therefore, this paper focuses the identification of issues and problems of BQT at each construction work item level based on two categorizations of structural works and interior works.

• Korean Journal of Construction Engineering and Management
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• v.14 no.1
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• pp.12-22
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• 2013

Construction industry throughout the construction projects life cycle using BIM is able to manage information. Among them, BIM-based quantity take-off is directly connected to the data of the construction business as an important management element that is essential for one of the management factors of feasibility study and economic analysis. In addition, the result of BIM-based quantity take-off can be varied depending on modeler, so the exact guideline for BIM modeling is necessary. The BIM-based quantity take-off in terms of reliability and accuracy of the information is very important. Therefore, this study verified the BIM modeling of the apartment interior materials using both separate object and composite object was validated the quantitative comparison of the difference in BIM-based quantity take-off for accuracy & reliability judgment of BIM-based quantity take-off and realistic & desirable suggestion of BIM modeling way. As the result of this study, it is preferable to model various interior materials to use separate object for the purpose of correct BIM-based quantity take-off, but the realistic way of the BIM modeling using both separate object and composite object jointly was verified in order to judge BIM-based quantity take-off in terms of work productivity.

• Korean Journal of Construction Engineering and Management
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• v.12 no.6
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• pp.79-92
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• 2011

Quantity take-off is one of the critical tasks that determine the cost of a construction project, and its result should be accurate and reliable. BIM-based quantity take-off is a very attractive process for practitioners since the quantity take-off can be done automatically in a fast and accurate way. However, the result of BIM-based quantity take-off can be varied depending on how BIM was modeled. As a project progresses, more detailed design information is getting available, and it can be expected that the degree of completeness and accuracy for the BIMbased quantity take-off is going to be improved as well. However, when estimation is performed at each stage of a project life-cycle, there is no way to measure or forecast how accurate of the quantity take-off result from the BIM data given at the current stage. Therefore, this research derived factors that affect the BIM-based quantity takeoff and developed a methodology and framework to measure and forecast the completeness of BIM-based quantity take-off. The measurement framework and index that are proposed by this research was verified and validated for their consistency and feasibility through six pilot projects.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1113-1116
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• 2009

The attempt to use a 3D model each field such as design, structure, construction, facilities, and estimation in the construction project has recently increased more and more while BIM (Building Information Modeling) that manages the process of generating and managing building data has risen during life cycle of a construction project. While the 2D Drawing based work of each field is achieved in the already existing construction project, the BIM based construction project aims at accomplishing 3D model based work of each field efficiently. Accordingly, the solution that fits 3D model based work of each field and supports plans in order to efficiently accomplish the relevant work is demanded. The estimation, one of the fields of the construction project, has applied BIM to calculate quantity and cost of the building materials used to construction works after taking off building quantity information from the 3D model by a item for a Quantity Take-off grouping the materials relevant to a 3D object. A 3D based estimation program has been commonly used in abroad advanced countries using BIM. The program can only calculate quantity related to one 3D object. In other words, it doesn't support the take-off process considering quantity of a contiguous object. In case of temporary materials used in the frame construction, there are instances where quantity is different by the contiguous object. For example, the formwork of the temporary materials quantity is changed by dimensions of the contiguous object because formwork of temporary materials goes through the quantity take-off process that deduces quantity of the connected object when different objects are connected. A worker can compulsorily adjust quantity so as to recognize the different object connected to the contiguous object and deduces quantity, but it mainly causes the confusion of work because it must complexly consider quantity of other materials related to the object besides. Therefore, this study is to propose the solution that automates the formwork 3D modeling to efficiently accomplish the quantity take-off of formwork by preventing the confusion of the work which is caused by the quantity deduction process between the contiguous object and the connected object.