• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.559-566
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• 2008

This paper describes the state-of-the-art and -practice of embedded precast pile methods in Korea. The current status of embedded precast piling was reviewed in terms of its design, construction and quality assurance available for last decade in Korea. Based on the results obtained, some suggestions and authors' experience were proposed to design and construct the embedded precast pile foundations.

• Proceedings of the Korea Concrete Institute Conference
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• 1991.10a
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• pp.152-157
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• 1991

Expert systems represent the application of artificial intelligence research that is at least 10-15 years old. It may well take another 5-10 years before the present technology is exploited by industry. The objective of this paper is to show the applicability of Combined Hypertext-Expert System Techniques to the professionals working in the construction industry. Expert systems alone don't give the user any control over the system. Hypertext systems that focus only on displaying messages have the opposite problem. While they allow the user to control the system., the only control the system designer has is in setting up the hypertext links. Therefore the combination of these two techniques, offered by KnowledgePro, may bring us closer to real user-expert communication. The system developed in this work offers information on ACI Manual concerning various problem areas in concrete practice, consultation about mix design of concrete and guidance to identify types of cracks in concrete. Once the type of crack is identified through the rule-based knowledge, the system provides the user with remedial measures through the control of the user.

• Journal of Information Management
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• v.42 no.2
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• pp.43-65
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• 2011

Despite a long tradition and rich discussion of thesaurus construction, more research is needed to make standards for thesaurus construction applicable to practice. Recently, in order to reflect changing information technology environment, and provide consistency of terms and abbreviations of standards, ISO committee has been planning to publish ISO 25964. Therefore, the study introduces ISO 25964, reveals main focal points of ISO 25964, and finally discusses suggestions to improve ISO 25964. The study employs qualitative content analysis of ISO 25964, ISO 2788: 1986, and ANSI/NISO Z39.19 - 2005.

• International Journal of Concrete Structures and Materials
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• v.7 no.2
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• pp.155-163
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• 2013

The use of sustainable technologies such as supplementary cementitious materials (SCMs), and/or recycled materials is expected to positively affect the performance of concrete mixtures. However, it is imperative to qualify and implement such mixtures in practice, if the required specifications of their intended application are met. This paper presents the results of a laboratory investigation of self-consolidating concrete (SCC) containing sustainable technologies. Twelve mixes were prepared with different combinations of fly ash, slag, and recycled asphalt pavement (RAP). Fresh and hardened concrete properties were measured, as expected the inclusion of the sustainable technologies affected both fresh and hardened concrete properties. Analysis of the experimental data indicated that inclusion of RAP not only reduces the ultimate strength, but it also affected the compressive strength development rate. The addition of RAP to mixes showed a consistent effect, with a drop in strength after 3, 14, and 28 days as the RAP content increased from 0 to 50 %. However, most of the mixes satisfied SCC fresh properties requirements, including mixes with up to 50 % RAP. Moreover, several mixes satisfied compressive strength requirement for pavements and bridges, those mixes included relatively high percentages of SCMs and RAP.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.723-729
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• 2001

Electro-hydraulic shift control of a vehicle automatic transmission has been predominantly carried out via an open-loop control based on numerous time-consuming calibrations. Despite remarkable success in practice, the variations of system characteristics inevitably deteriorate the performance of the tuned open-loop controller. As a result, the controller parameters need to be continuously updated in order to maintain satisfactory shift quality. This paper presents a self-learning algorithm for automatic transmission shift control in a construction vehicle during inertia phase. First, an observer reconstructs the turbine acceleration signal (impossible to measure in a construction vehicle) from the readily accessible turbine speed measurement. Then, a control algorithm based on a quadratic function of the turbine acceleration is shown to guarantee the asymptotic convergence (within a specified target bound) of the error between the actual and the desired turbine accelerations. A Lyapunov argument plays a crucial role in deriving adaptive laws for control parameters. The simulation and hardware-in-the-loop simulation (HILS) studies show that the proposed algorithm actually delivers the promise of satisfactory performance despite the system characteristics variations and uncertainties.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.176-183
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• 2003

This paper presents a neural network based approach to disseminating information relating to experimental and field observations in engineering. Although the methodology is generic and can be applied to many areas of engineering science, attention is focussed here solely on geotechnical engineering applications. Field data relating to the settlement of foundations presented by Burland and Burbidge (1985) which led to their well known equation for calculation of settlement, now included in most text books, is re-visited. A part of the data, chosen randomly, is used to train an Artificial Neural Network (ANN), which relates foundation settlement to various causes as identified by the authors. Predictions are made for situations for which data were not used in training. These indicate sufficient accuracy when compared to the original field data. Accuracy of predictions is further improved when all the data are included in the training set. The finally trained ANN is shown to represent these data more accurately than the Burland and Burbidge equation. Based on the above heuristic example, an ANN is presented as an alternative to developing equations and design rules in geotechnical engineering practice. Significant advantages are shown to arise by using this methodology. Ease of updating the ANN, as and when additional data becomes available, being the most important one. Loss of transparency, however, seems to be the main disadvantage.

• Plant Journal
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• v.6 no.1
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• pp.56-63
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• 2010

While the local plant market is reducing its volume, the plant market over the world since 2000s is rapidly expanding. The nation's construction companies, aggressively dedicated in launching out overseas plant market, increase the volume of orders in that sector, but there also are much difficulty in the project management as those projects ordered are gradually large scaled with more cutting-edge high-tech requirements along with comparatively higher risk. Though the local construction companies have developed their own types of measures to analyze the risk evaluation putting into practice, the specialized decision-making model for the overseas plant market or the risk measure understandable easily and applicable practically is not yet shown. This paper aims at providing the methodology to evaluate the risk by way of constructing the risk evaluation process in order to induce risk measuring elements through appropriate indexing system. Furthermore, through studying the risk management system, it aims to seek for a thorough risk management method from beginning of the project to the end.

• International Journal of High-Rise Buildings
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• v.6 no.1
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• pp.83-89
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• 2017

Due to the time-dependent properties of materials, structures, and loads, accurate time-dependent effects analysis and precise construction controls are very significant for rational analysis and design and saving project cost. Elevation control is an important part of the time-dependent construction control in supertall structures. Since supertall structures have numerous floors, heavy loads, long construction times, demanding processes, and are typically located in the soft coastal soil areas, both the time-dependent features of superstructure and settlement are very obvious. By using the time-dependent coupling effect analysis method, this paper compares Shanghai Tower's vertical deformation calculation and elevation control scheme, considering foundation differential settlement. The results show that the foundation differential settlement cannot be ignored in vertical deformation calculations and elevation control for supertall structures. The impact of foundation differential settlement for elevation compensation and pre-adjustment length can be divided into direct and indirect effects. Meanwhile, in the engineering practice of elevation control for supertall structures, it is recommended to adopt the multi-level elevation control method with relative elevation control and design elevation control, without considering the overall settlement in the construction process.

• Journal of the Korea Concrete Institute
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• v.11 no.3
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• pp.141-152
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• 1999

Precast prestressed double-tee slab may be designed by the PCI Design Handbook. It is based on the bridge construction and is required for reorganization for the use of buildings in the domestic construction environments. Much enhanced sections are developed from the reforming process on the determined design factors in the previous experimental works on double tees. Pre-determined shape, reinforcement detail, and 5000 psi concrete strength can not be expected as the best solution for the domestic construction requirements because large amount of use on that systems are anticipated. Flexural tests are performed on four full-scale 12.5m proto-type models, "least depth double tee", which are resulted from the optimization process. Domestic superimposed live load regulation, domestic material properties which is available to product, building design requirements and economy in construction are considered as the main factors to establish. the first two sections are double tee section for 1.2 ton/$\m^2$ market live load with straight and one-point depressed strands and the second two are for 0.6 ton/$\m^2$ parking live load with those strand types. All of the specimens tested fully comply with the flexural strength requirements as specified by ACI 318-95. However, the research has shown that following improved considerations are needed for better result in practice. The locations and method of connection for the lowest bottom mild bar, connection method between precast and cast-in-place concrete, and dap-end reinforcement are need to be improved.

• Journal of the Korea Institute of Building Construction
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• v.9 no.3
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• pp.117-125
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• 2009

With construction industry recession, many construction companies are increasingly conducting the development projects by themselves. However, housing projects requested by developers still stand large portion. Although many studies on feasibility analysis were released, they mainly focused on economic feasibility and lacked research on factors and criterions of overall project. Also, because previous studies overly break downed factors related to project, they rarely used in practice. Therefore, this study developed the feasibility analysis model of housing development projects to help main contractors to easily and effectively decide if it is feasible enough to promote the projects requested by developers, and verified the reliability of the model. In this study, thirty one driving factors were identified under seven different categories and the criterion of each factor was also developed. The survey on important index of each factor found 'salability', 'economic feasibility', 'site location' and 'method of raising fund' significant. 12 projects were tested by the model and its results showed resonable reliability.