• Journal of Aerospace System Engineering
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• v.14 no.5
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• pp.100-106
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• 2020

Turbopumps for liquid rocket engines are exposed to various cavitation instabilities under their operating conditions. The instabilities affect the stability of the turbopumps. To make sure of the stability of the turbopump of KSLV-II, the present work examined the characteristics of the cavitation instabilities during the turbopump assembly test. In the test, the LOx pump was operated under super-synchronous rotating cavitation and attached to uneven cavitation. In the vibration analysis of the fuel pump, the characteristic frequency by the super-synchronous cavitation of the LOx pump was clearly shown.

• Design & Manufacturing
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• v.6 no.2
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• pp.74-78
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• 2012

A multi-cavity injection mold system of protein chip for point-of-care with cavity temperature and pressure sensors was proposed in this work. In advance of manufacturing for the multi-cavity injection mold system, a single cavity injection mold system to mold protein chip was considered. Injection molding analysis for the presented system was performed to optimize the process of the molding and suggest guides to design. On the basis of the results for the single cavity system, a multi-cavity injection mold system for protein chip was analyzed, designed and manufactured with cavity temperature and pressure sensors. Results of balanced filling for protein chip models were obtained from the presented mold system.

• Analytical Science and Technology
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• v.14 no.5
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• pp.400-409
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• 2001

A method for the analysis of most common phthalate acid esters (9 secies) in biota samples by gas chromatography-mass spectrometry-selected ion monitoring mode is described. Phthalates in biota samples are extracted by organic solvent and purified by Florisil column. Phthalates are easily contaminated during extraction prodedure. Since the extraction and cleanup steps for biota samples generally are more complicate than those for water or sediment samples, we compared with contamination state of each sample work-up step. By applying this developed method, the overall recoveries ranged between 79 - 117% in biota sample which was spiked with standards. For phthalates used in this study, the quantitaive accuracy, elution pattern on Florisil column, and detection limits were also investigated.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1234-1242
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• 2010

In this study, the effect of noise and vibration, and influence of ground improvement are evaluated and its application is analyzed through the example of SCP designed at ground improvement in Song-Do international city. consequently, it showes even comfortable result that it is about 5.0m of inner space, when the LVSCP method is applied, rather than that it is about 30m of inner space when the existing SCP is applied in vibration control standards 2.0mm/sec. In the noise, now that the many differences according to environmental factors like other equipment noise, limited space and so on at the time of the construction by LVSCP method are coming out, so we think that appro itate measures are needed according to surroundings. By the way, when it comes to the estimation of the ground improvement work before and after an improvement of LVSCP method, its result shows that it is satisfacttion to all the standards of compaction control in dregded and reclaimed ground and sedimentary clay layer.

• Korean Journal of Health Education and Promotion
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• v.28 no.1
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• pp.115-130
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• 2011

Objective: This study aimed to introduce Health Impact Assessment using the case of a HIA on 2008 Dream Start Project in Cheongju. Methods: We followed the typical procedure of HIA recommended by the Merseyside Guidelines on HIA. In scoping, the steering committee decided 5 key domains of child health to be assessed: prenatal care, vaccination, nutrition, access to health care, and child abuse and also the methods of collecting the evidence. The HIA appraisal team collected information from various sources including literature, community survey, and focus group interviews. The HIA appraisal team also synthesized the collected information in terms of the nature of health impacts and equity and made recommendations accordingly. Results: Positive impacts were expected in prenatal care, vaccination, and nutrition, while negative impacts were expected in access to health care. The impact of Dream Start on child abuse was uncertain. Several recommendations were made and submitted to the Dream Start team for their consideration. About 2 years later, we found many of them were implemented in 2009 Dream Start project. Conclusion: HIA was found to be applicable and effective to make decision makers in the welfare sector consider health in their work.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.1
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• pp.65-71
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• 2007

Adjustable autonomy architecture provides various ways for a human operator to participate as a member of a human-robot team in improving the performance of the team by resolving issues that the robots cannot deal with or performing tasks that the robots alone would unable to do. According to the level of involvement of the human operator, the robots have to adjust their level of autonomy and, in consequence, the operation mode of the overall system shifts. This paper deals with the implementation issues of seamless switching when the level of autonomy of the human-robot team shifts from one level to another. Especially, we focus on developing reliable methods for monitoring the task progress and maximizing the system flexibility by coping with the detailed differences between humans and robots in their characteristics of motions and their choices of positions, paths, and sequences of sub-goals to achieve a given task. To test and motivate the proposed methods, we have assembled three heterogeneous robots which work together to dock both ends of a suspended beam into stanchions.

• Journal of Engineering Education Research
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• v.20 no.1
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• pp.53-62
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• 2017

This paper explored how university students viewed flipped learning from their own perspectives. Using qualitative research methods, 5 students from a Computer Graphics course at a mid-scale university in Seoul were interviewed for this purpose. Researchers collected data about their learning experiences, emotions, and reflections about flipped learning in general and its components such as online materials, in-class activities, and instructor guidance. Research findings indicated that students were not so much conscious about the unfamiliarity of the class, the increased work load, nor the online lectures. They rather prioritized 'what they could actually learn' from the course, and thus defined flipped learning as a method which enabled students to constantly check and fill in the gaps in their learning through team-based activities and prompt feedback from the professor. A combination of students' positive attitude and active participation in team-based activities, the overall atmosphere of the department which supported interactivity and collaboration, the professor's emphasis on learning-by-doing and student-centered learning appeared to form their notions of flipped learning. The use of technology did not appear to heavily impact students' conceptions of flipped learning. Researchers suggest that pedagogical beliefs of the professor, culture surrounding the learner, and the good match between the course content and instructional strategies are central for designing a successful flipped learning class.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.309-309
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• 2010

We have investigated the effect of $H_2$ plasma treatment on the BZO (ZnO:B, Boron doped ZnO) thin films. The BZO thin films are prepared by LP-MOCVD (Low Pressure Metal Organic Chemical Vapor Deposition) technique and the samples of BZO thin film are performed with $H_2$ plasma treatment by plasma treatment system with 13.56 MHz as RIE (Reactive Ion Etching) type. After exposing $H_2$ plasma treatment, measurement of transmittance, reflectance and haze spectra in 300~1100 nm, electrical properties as resistivity, mobility and carrier concentration and work function was analysed. Regarding the results of the $H_2$ plasma treatment on the BZO thin films are application to the TCO for solar cells, such as the a-Si thin films solar cell.

• Special Issue of the Society of Naval Architects of Korea
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• 2007.09a
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• pp.14-21
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• 2007

A passenger ship is consist of five(5) constituents; passenger, sea, crew, port and ship itself and the rule & regulation which is applicable to passenger ship are differently required as their objects of constituents. the basic concept of rule & regulation can be defined all activities to keep safety of ship and her constituents. Especially, the rule & regulation for passenger ship design and construction shall be considered not only safety of ship itself but also safety of lives, so its are required more severe than commercial vessel. Recently, the IMO have finished the rule making work on the 'passenger ship safety' since it has been discussed last 2000 and next MSC meeting will be adopted the results. In this paper, the application method of rule & regulation are treated and the new rule which were made by IMO are introduced. The rule & regulation for passenger ship is one of the most important things. therefore, it is required to careful consideration to apply on the rule application.

• Korean Journal of Construction Engineering and Management
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• v.7 no.4 s.32
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• pp.164-176
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• 2006

Conflict may occur during teamwork activities. Conflict is the incompatibility of interest of participants; hence, it is more common in a wide varied activities involved construction field. Goals and values involve positive or negative features and are therefore common sources of conflict in construction field. Excessive conflict is a major hindrance to the effective operation of a team. If the conflict is not managed timely and properly, it could be transformed into a big dispute, thus to avoid these situation, it is necessary to augment working together culture. This paper aims to identify project team working factors and to uncover underlying relationships between these factors. A questionnaire survey was used to collect data from professionals. Factor analysis was employed to categorize twenty-one teamwork items evaluated by 169 respondents working in three major construction parties namely, owners, consultants and contractors. Factor analysis uncover that these team work factors can be grouped under three categories titled as: integrative working culture, relationship building and trust building. Multiple regression analysis however, showed that relationship building factor does not influence job satisfaction of project participants. Results of this study can be used as a tool to strengthening relationship between project participants in the construction industry.