• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.268-270
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• 1995

In crane drives, DC motor has been most widely used due to simple control characteristic and favorable transient behavior. Nowadays, however, the squirrel cage induction motor is known as an attractive candidate due to elimination of all sliding electrical contacts, resulting in an exceedingly simple and rugged construction. Especially, in hoist application, the smooth torque control and four quadrant operation are essential. In this paper, an operation of dual inverters with common DC bus fed by vector controlled induction motor is described. Single DSP is employed as a main processor to control dual inverters and communicates each input/output signal with PLC. As well as giving a detailed expression, full simulation and experimental results are presented.

• Journal of Ocean Engineering and Technology
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• v.33 no.2
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• pp.178-188
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• 2019

When burying underwater cables using robots, heading control is one of the key functions for the robots to improve task efficiency. This paper addresses the heading control issue for URI-T, an ROV for underwater construction tasks, including the burial and maintenance of cables or small diameter pipelines. Through modeling and identifying the heading motion of URI-T, the dynamic characteristics and input limitation are analyzed. Based on the identification results, a PD type controller with appropriate input treatment is designed for the heading control of URI-T. The performance of the heading controller was verified in water tank experiments. The field applicability of the proposed controller was also evaluated through the sea trial of URI-T at the East Sea, with a water depth of 500 m.

• Journal of the Korea Institute of Building Construction
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• v.19 no.3
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• pp.263-272
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• 2019

Building Information Modeling (BIM) and modular construction are regarded as important technologies that have contributed to advancements in the construction industry. However, the utilization of BIM in current modular construction projects is limited; moreover, there are no specific guidelines pertaining the applications of BIM in modular construction projects. Therefore, this study aims to analyze the utilization of BIM for onsite construction planning in modular construction projects. First, a realistic BIM application was selected through literature review and expert interviews. Then, the construction plan of the modular projects was analyzed to classify the BIM application items into five different categories. The utilization of BIM in each category was then analyzed in terms of necessity and efficiency using a questionnaire. Finally, the BIM Utilization Index (BIM UI) was suggested based on the findings of the survey. As a results, the BIM UI for module point details, lifting plan, other installation details, site layout plan, and schedule plan was 0.811, 0.787, 0.770, 0.729, and 0.699, in the descending order of usability. In addition, through the findings of the study and interviews with experts, a case study for implementation of BIM in modular construction plan was conducted. The results of this study can be used as application guidelines for BIM in future modular construction projects.

• Journal of Industrial Technology
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• v.16
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• pp.131-137
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• 1996

For a large scale civil and architectural structures, mainly steel, concrete and aluminum have been used and weight and corrosion of materials became a major concern. Designing with composite materials is very much complicated. Simple classical theory may yield good results for selecting "initial" sections for preliminary design. D. H. Kim proposed to use the quasi-isotropic constants by Tsai for the preliminary design of the composite primary structures for the civil construction. Also he made simple equation using correction factor. In this paper, the simple formulas developed by D. H. Kim to obtain "exact" values of the natural frequencies of [ABBCAAB]r laminate are compared with Whitney's equations. Also natural frequencies of the plate with varying aspect ratios and reinforcing fiber orientations, are compared with natural frequencies of bean. This work can be a guideline to obtain data in many other cases.

• Bulletin of the Korean Space Science Society
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• 2011.04a
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• pp.30.1-30.1
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• 2011

We present construction of 3D Earth optical Model for in-orbit performance prediction of L1 halo orbiting earth remote sensing instrument; the Albedo Monitor and Radiometer (Amon-Ra) using Integrated Ray Tracing (IRT) computational technique. The 3 components are defined in IRT; 1) Sun model, 2) Earth system model (Atmosphere, Land and Ocean), 3)Amon-Ra Instrument model. In this report, constructed sun model has Lambertian scattering hemisphere structure. The atmosphere is composed of 16 distributed structures and each optical model includes scatter model with both reflecting and transmitting direction respond to 5 deg. intervals of azimuth and zenith angles. Land structure model uses coastline and 5 kinds of vegetation distribution data structure, and its non-Lambertian scattering is defined with the semi-empirical "parametric kernel method" used for MODIS (NASA) missions. The ocean model includes sea ice cap with the sea ice area data from NOAA, and sea water optical model which is considering non-Lambertian sun-glint scattering. The IRT computation demonstrate that the designed Amon-Ra optical system satisfies the imaging and radiometric performance requirement. The technical details of the 3D Earth Model, IRT model construction and its computation results are presented together with future-works.

• Journal of Korean Institute of Industrial Engineers
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• v.24 no.1
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• pp.95-103
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• 1998

This paper deals with technology relevance analysis, which measures technological dependency between needs technology and its component technology as well as between needs technologies. The two-round survey was carried out: In the first round, a wide range of needs technologies in construction and building industry were identified and classified to meet a variety of social needs which were anticipated in the near future of Korea. In the second, relevance between needs technology and its component technologies was checked by some 120 experts. Based on the survey results, the individual relevances among needs technologies were computed. Finally the ranking of needs technologies in construction industry was set according to the degree of technology relevance. This relevance is to be used as one of criteria for the selection of national R&D projects which the Ministry of Construction and Transportation plans to promote in the next five years.

• Journal of Korean Association for Spatial Structures
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• v.18 no.1
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• pp.67-75
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• 2018

Steel roof construction is on the most important and critical factors in the large spatial construction and necessary to be prepared under a radical planning. Therefore, the major management factors of steel roofing structure assembly must be critically reviewed during planning. Through the review process, it is necessary to reduce the construction cost, to prevent delays in the construction schedule, and to minimize construction errors. However, domestically due to the lack experience in large spatial constructions, a planning of roof construction is limited to have a radical planning. Especially due to unclear organization of the management factors in hierarchy, using them in reality for construction planning is difficult and reliability is low. Therefore, in this study, the goal is to conduct the major management factors in the large spatial construction. To achieve this, we have reviewed and analyzed the numbers of construction plans and construction reports and conducted a total 68 of the management factors. Based on the conducted factors, we have interviewed 16 experts with experience in large spatial construction. From the interview result, we have deduced the factors scored above 4.20 of 10 for critical factors. The results of this study will be used as a guidance for planning steel roofing structure assembly in large spatial construction. The critical factors will be provided to the site mangers for the quality management of large spatial constructions in practice.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.70-80
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• 2020

This study examined the effects of the R&D project managers' leadership on the product development performance. A survey was carried out empirically on a group of 175 experts associated with project management R&D operations in the field of manufacturing, construction engineering, shipbuilding, plant, and IT. The survey results showed that the effects of the R&D project managers' leadership on the product development performance were not significant, and the mediating effects of the project sponsor roles were significant. This means that the leadership of leaders, which requires efficient control and management based on complicated intergroup relationships and roles, is important in a project involving experts from the professional field. This suggests that the efficient leadership of leaders can improve the performance through the cooperation of members in the organization and aggregation of their core competencies in a limited time. Overall, the key results of this study mean that project leaders should play an active mediating role to maximize their leadership and enhance the role of project sponsors. In addition, the mediating role of project sponsors has an effect on the leadership of project managers, affecting the project performance quality.

• International conference on construction engineering and project management
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• 2017.10a
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• pp.1-7
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• 2017

Korea's domestic construction market and overseas construction order environment are experiencing a decreasing trend, and this trend is expected to continue. Therefore, domestic construction companies are seeking to enter the global construction market. This study analyzes the global construction market and the global competitiveness for global construction companies and provides the results. To this end, this study has developed a model to evaluate the global construction competitiveness level and to evaluated global construction competitiveness in 2016. The evaluation of global construction competitiveness was analyzed based on the competitiveness of construction infrastructure by country, and the evaluation results of competitiveness of construction companies. These assessments were based on 20 detailed international statistics (ENR, Global Insight, Compass, etc.). The evaluation results are as follows. First, in regard to the comprehensive global construction competitiveness by country, America ranked first among 20 countries, followed by China. European countries like Spain, Germany and the Netherlands ranked third to fifth, respectively. Korea ranked sixth, one rank higher than that of the previous year. America and European countries remain strong. Second, in regard to the comprehensive building infrastructure competitiveness by country, America ranked first followed by Germany. Korea ranked twelfth, which is the same rank as that of the previous year. When it comes to stability in the construction market, China ranked first and Korea eighth. For construction systems, Sweden ranked first and Korea thirteenth, and for infrastructure, Japan ranked first and Korea tenth. Third, according to the construction company's capability evaluation by country, America ranked first followed by China. Korea ranked fourth, two ranks higher than that of the previous year because of its building competitiveness (fifth → fourth) and design competitiveness (eleventh → eighth) which has improved. When it comes to building competitiveness, China ranked first and Korea fourth. For design competitiveness, America ranked first and Korea eighth, and for price competitiveness, India ranked first and Korea seventh. However, Korea is still in the middle of the pack rank among the 20 countries considered when it comes to design competitiveness. It is ranked eleventh for design productivity and thirteenth for foreign sales against the total sales (internationalization). Thus, Korea needs to improve technical power and tap into new markets for improved competitiveness, including increased productivity. To do so, more R&D investment is required.

• The Journal of Korean Medicine
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• v.28 no.1 s.69
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• pp.42-50
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• 2007

Objectives . This study was to assess the Korean Traditional Medicine forecast subjects that had been expected to be accomplished by 2005. The result will help the Korean medical society plan far policies and studies on Korean Traditional Medicine. Methods : Assessed targets were 64 subjects (expected to be studied until 2005) of the total 93 subjects from the 'Mid- to Long-Term Forecast and Plan Study for Korean Traditional Medicine'. The subjects were classified into two types : political subjects and research and development (R&D) subjects. These were determined by the quantity and contents of related political reports, political research projects, thesis, patent, placing products on sale, etc. Results :1) 5 items of a total 12 political subjects were accomplished or partially accomplished (41.7%), and 9 items of a total 46 R&D subjects were accomplished or partially accomplished (9.5%). 2) While the accomplishment percentage (accomplished or partial accomplished) in literature arrangement and D/B construction field was 100%, it was under 10% in product or system development field. Thus, it seems that practical subjects were less accomplished than academic subjects. 3) On 8 subjects of 'Forecast Research on Future of Oriental Medicine' which had been performed in Japan, the Korean expected dates when the subjects would be realized were earlier than the Japanese ones, but no subjects were realized. Conclusion · Political and academic subjects weir accomplished more than R&D and practical subjects.