• Applied Microscopy
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• v.34 no.3
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• pp.159-170
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• 2004

Spermiogenesis in the Korean squirrel, Tamias sibiricus, was investigated by transmission electron microscopy. Spermiogenesis was divided into Golgi, cap, acrosome, maturation and spermiation phases based on the characteristics of acrosomal changes and nuclear shape. Beside, the Golgi, cap and acrosomal steps were subdivided into three phases of early, middle and late phase respectively, the maturation step was divided into two phases of early and late phase, and spermiation step has only one phase. Thus, the spermiognesis of T. sibiricus was divided into a total of twelve phases. In Golgi phase (steps 1-3), a well developed Golgi complex was located close to the vesicles, the acrosomal vesicle fixd to a recess of nuclear membrane at step 3. During cap phase (steps 4-6), the acrosomal vesicle spred over the nuclear surface to cover a third of the nucleus, and the acrosomal granule was not yet flattened. At acrosomal phase (steps 7-9), the nucleus and acrosome were elongated but nucleoplasm was not condensed. During maturation phase (steps 10-11), the nucleoplasm was more condensed, and the mitochondria completely arranged the center of axoneme. The spatulate-sperm head was completely formed at spermiation phase (step 12).

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.6
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• pp.757-770
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• 1998

A Navier-Stokes code with a low Reynolds number k-.epsilon. turbulence model was tested to investigate its predictability for the unsteady transitional boundary layer flow due to rotor-stator interaction. A preliminary calculation with three different numbers of time steps 300, 600, and 1000 for a rotor wake passing period was carried out to see the effects of time steps on the unsteady flow and pressure fields due to rotor-stator interaction. Numerical solutions showed that unsteady pressure was much more sensitive to the number of time steps and over 600 time steps should be used to get a numerical solution independent of the number of time steps for a rotor wake passing period. The original low Reynolds number k-.epsilon. turbulence model showed very poor prediction of the unsteady transitional boundary layer flow due to rotor-stator interaction. This was due to the excessive production of turbulent kinetic energy near the leading edge. A modification suggested by Launder was incorporated and the modified model captured well the wake induced transitional strip. Present solutions also showed improved prediction over previous Euler/boundary layer solution in terms of the onset of unsteady transition and its extent.

• Nuclear Engineering and Technology
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• v.35 no.5
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• pp.412-425
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• 2003

According to the results of related studies, one of the typical factors related to procedure related human errors is the complexity of procedures. This means that comparing the change of the operators' behavior with respect to the complexity of procedures may be meaningful in clarifying the reasons for the operators' non-compliance behavior. In this study, to obtain data related to the operators' non-compliance behavior, emergency training records were collected using a full scope simulator. And three types of the operators' behavior (such as strict adherence, skipping redundant actions and modifying action sequences) observed from the collected emergency training records were compared with the complexity of the procedural steps. As the results, two remarkable relationships are obtained. They are: 1) the operators seem to frequently adopt non-compliance behavior to conduct the procedural steps that have an intermediate procedural complexity, 2) the operators seems to accommodate their non-compliance behavior to the complexity of the procedural steps. Therefore, it is expected that these relationships can be used as meaningful clues not only to scrutinize the reason for non-compliance behavior but also to suggest appropriate remedies for the reduction of non-compliance behavior that can result in procedure related human error.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.1 s.190
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• pp.85-92
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• 2007

In the present study, three-dimensional motion analyses were performed to determine biomechanics of the lower extremity in unexpected missing foot steps for ten healthy young volunteers. In unexpected missing foot steps, the whole plantar surface of the foot or the heel contacted to the ground. A rapid ankle dorsiflexion was found right after missing foot steps and an increased plantarflexion moment was noted during loading response. After the unexpected situation, the breaking force increased rapidly. At this time, both tibialis anterior and soleus were simultaneously activated. Moreover, the range of motion at ankle, knee and hip significantly decreased during stance. In pre-swing, rectus femoris and biceps femoris prevented the collapse of the lower limbs. During late stance, propulsive forces decreased and thus, both plantarflexion moment and power generation were significantly reduced. On the opposite side, hip extension and pelvic upward motion during terminal swing were significant. Due to the shortened pre-swing, the energy generation at the ankle to push sufficiently off the ground was greatly reduced. This preliminary study would be helpful to understand the biomechanics of unexpected dynamic perturbations and valuable to prevent frequent falling of the elderly and patients with gait disorders.

• Journal of Korean Institute of Industrial Engineers
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• v.20 no.4
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• pp.51-63
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• 1994

Many themes have been studied for FMS problems. But most researches have focused on specific themes; Machine selection, Loading, Routing, Machine layout, etc. So many decision makers who want to introduce FMS to his factory, have many problems, because they do not know either what size of FMS should be introduced or what amount of money should be invested. The objective of this research is to help the decision makers who want to introduce FMS. This research consists of three major part, first, Machine selection, second, Loading, and third, Machine Layout. In the first part of the research, machines are selected with minimum cost satisfying the given demand of each part. In the second part, each operations with its required tools are allocated to those machines. In the third part the locations of each selected machines are determined. And dissimilarity coefficients between each pair of machines are calculated as the measure of distance. With above three steps, we have selected machines, allocated operations to those machines, and the layout configuration of those machines. And for each three steps, Mixed Integer Programming models are formulated. In order to solve the large problems and reduce the computer execution time, three heuristic algorithms are developed for the three mixed integer programming models.

• Journal of Engineering Education Research
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• v.17 no.2
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• pp.11-24
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• 2014

The purpose of this study is to develop a teaching-learning model of convergence project based on team teaching. Based on development research methodology which explored a university case, the teaching-learning model was developed including three phases such as preparation, planning, and implementation & evaluation. The preparation phase has three steps as follows: to organize team teaching faculty; to develop convergence projects cooperated by industry and university; and to design instructions based on supporting convergence projects. The last step of preparation phase consists of five design activities of: (1) instructions and teaching contents; (2) communication channel among faculty members; (3) feedback system on students' performance; (4) tools to support learners' activity; and (5) evaluation system. The planning phase has two steps to analyze learners and to introduce and modify instruction and themes of convergence projects. The implementation & evaluation phase includes five steps as bellow: (1) to organize project teams and match teams with faculty members; (2) to do team building and assign duties to students of a team; (3) to provide instruction and consulting to teams; (4) to help teams to conduct projects through creative problem solving; and (5) to design mid-term/final presentation and evaluation. Lastly, the research implications and limitations were discussed for future studies.

• Journal of Pharmaceutical Investigation
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• v.22 no.3
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• pp.49-63
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• 1992

Two different types of chemical manipulations of dobutamine were investigated in order to develop novel, improved cardiotonic drugs. Three new analogues of carbostyril, in which the m-hydroxy group of dobutamine was isosterically modified with an amide type carbostyril system, were synthesized from, ${\rho}-methoxyphenethylamine$ via multi-steps. Two analogues of (2'-aminoethyl)-1-hydroxy-2-pyridone system which has isosteric structural similarity with dopamine without having the COMT vulnerable m-hydroxy group were synthesized via 12 synthetic steps. Their biological stabilities in various media and inotropic activities were evaluated.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.28 no.4
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• pp.94-101
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• 2005

This paper presents a data-mining aided heuristic algorithm development. The developed algorithm includes three steps. The steps are a uniform selection, development of feature functions and clustering, and a decision tree making. The developed algorithm is employed in designing an optimal multi-station fixture layout. The objective is to minimize the sensitivity function subject to geometric constraints. Its benefit is presented by a comparison with currently available optimization methods.

• Bulletin of the Korean Chemical Society
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• v.16 no.9
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• pp.859-863
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• 1995

The prostaglandin analogue 12-epi-PGF2α (2) has been synthesized from optically active cis-4-t-butyldimethylsilyloxy-2-cyclopenten-1-ol (4b) in 4 steps in an overall yield of 21%. An extremely efficient Pd(Ⅱ)-mediated, three-component coupling reaction is employed to obtain the key intermediate 9.

• Journal of Korean Academy of Nursing Administration
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• v.5 no.3
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• pp.501-512
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• 1999

The aim of this study was to utilize the 20 steps in the three phases from the book, 'Twenty steps for developing a Healthy Cities Project $2^{nd}$ Ed., 1995, WHO/EURO' to survey Healthy Cities to identify the similarities and differences by implementation rates and perceived significances among Healthy Cities worldwide. For this study, a self-administered questionnaire was developed based on the book. The questionnaires were delivered by air-mail and e-mail to 213 Healthy City coordinators or directors in 43 nations from Jan 13 to Feb 10, 1999. The responses were gathered up until March 31 from 40 Healthy Cities in 17 nations, mostly in the USA and in the European regions. The main results are as follows; Overall the perceived significances were higher for healthy cities with higher implementation rates and there were significant differences for 'set-up office', 'plans strategy', 'increase health awareness', 'mobilize intersectoral action', and 'secure healthy public policy'. 1. According to national health system, the implementation rate, perceived significance and implementation ability of the 20 steps were higher in the healthy cities with a comprehensive-type health system as compared to those with an entreprenetrial & permissive health system. Overall there were significant differences in the steps 'mobilize intersectoral action', and 'secure healthy public policy'. steps which were predominant in the healthy cities with a comprehensive-type health system. There was no concordance in the ranks of implementation rate and perceived significant score. 2. According to the length of implementation time, the perceived significance and implementation ability were higher in healthy cities with more than 6 years compared to those with less than 6 years, although implementation rate was the same. Overall there was a significant difference in 'secure healthy public policy' the step which was predominant in the healthy cities with more than 6 years of implementation. 3. According to population covered by the Healthy City Project, the implementation rate and implementation ability were higher in healthy cities with more than a population of 100 thousand. There was no significant difference in perceived significance, but there were differences in the following, 'find finances', 'set-up office'. 'mobilize intersectoral action' in the implementation rate and implementation ability. These three steps were predominant in the healthy cities with a population of more than 100 thousand. 4. The population covered by the Healthy City Project was the only effective factor influencing the total implementation ability of each healthy city, and it was higher for those cities with a population of more than 100 thousand. In Conclusion, the implementation rate, the perceived significance and the implementation ability were higher in cities with a comprehensive -type health system, with more than 6 years of healthy city experience and with a population of more than 100 thousand. To increase the reliability and the validity of the questionnaire and the results of this study arising from lack of sufficient data, repeated study needs to be considered with a more refined questionnaire delivered to more healthy cities worldwide.