• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.4
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• pp.165-174
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• 2011

This research aims at the optimal constitution of sensors required to identify the structural shortcoming of roller-coaster. In this research we analyzed the dynamic characteristics of roller-coaster by three dimensional FE modelling, decided on the appropriate location and number of sensors through optimal transducer theory, abstracted the mathematical value of modal features before and after damage on the basis of optimally placed and numbered sensors. and then presented it as a primary information about the basic structure which would be applied to damage estimation. As a target structure, the roller-coater at Seoul Children's Grand Park was chosen and built as a model reduced by one twentieth in size. In order to consider the Kinetics features particular to the roller-coaster structure, we made an exact three-dimensional FE modelling for the model structure by means of Spline function. As for the proper location and number of sensors, it was done by applying EIM and EOT. We also estimated the damage from the combination of strength, flexibility, and model corelation after abstracting the value of modal features. Finally the optimal transducer theory presented here in this research was proved to be valid, and the structural damage was well identified through changes in strength and flexibility. As a result, we were able to present the optimal constitution of sensors needed for the analysis of dynamic characteristics and the development of techniques in dynamic characteristics, which would ultimately contribute to the development of health monitoring for roller-coaster.

• Journal of KIISE:Software and Applications
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• v.32 no.11
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• pp.1121-1135
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• 2005

This paper proposes a moving object extraction method using the contrast map and salient points. In order to make the contrast map, we generate three-feature maps such as luminance map, color map and directional map and extract salient points from an image. By using these features, we can decide the Attention Window(AW) location easily The purpose of the AW is to remove the useless regions in the image such as background as well as to reduce the amount of image processing. To create the exact location and flexible size of the AW, we use motion feature instead of pre-assumptions or heuristic parameters. After determining of the AW, we find the difference of edge to inner area from the AW. Then, we can extract horizontal candidate region and vortical candidate region. After finding both horizontal and vertical candidates, intersection regions through logical AND operation are further processed by morphological operations. The proposed algorithm has been applied to many video sequences which have static background like surveillance type of video sequences. The moving object was quite well segmented with accurate boundaries.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.8
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• pp.555-563
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• 2020

Foward-swept wings are known to possess superior aerodynamic performance compared to the conventional straight wings. However major concerns regarding forward-swept wings include divergence at lower airspeeds which require careful consideration at the design stage. As an endeavor to overcome such drawbacks, aeroelastic tailoring is attempted. In order to find an optimal ply sequence, recursive aeroelastic analyses is conducted and one-dimensional beam analysis coupled with simple aerodynamics is used for the improved computational efficiency and modelling convenience. The analysis used in this paper, DYMORE and analytic formula, both use one-dimensional beam model for the structure. Cross-sectional analysis for multi-cell NACA0015 airfoil section is conducted using VABS and oblique function is used for the sweep angle. Throughout the present aeroelastic tailoring, the maximum divergence speed of 290.2m/s is achieved which is increased by approximately 43% than that for the conventional ply configuration.

• Korean Journal of Health Education and Promotion
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• v.8 no.2
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• pp.74-86
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• 1991

This study tried to clear the characteristics of height growth pattern depending on Peak Height Velocity age in early, average and late groups. And in it, height growth tendency of girl students in age 7 to 18 years old was compared and investigated in order to know influencing factors, menarcheal age relation. The samples were senior girl students at high school in Seoul. Longitudinal data and survey data were collected in August, 1990. The results could be summarized as follows: 1. On distance curve, the height growth line in early group tended to be the highest and in late group the lowest. On the other hand, on velocity curve late group showed the highest peak and early group showed the lowest peak. In late group, velocity curve was too steep. Of course, these early, average and late groups were classified by PHV age. 2. In these three groups, late group showed the most growth amount per year. However, on distance curve, early group showed higher line than late group. Perhaps this means that peak growth amount in late group might have an effect on mean. 3. Growth amount of adolescence spurt age in these three groups was 6.86cm at age 9(early group), 7.27cm at l1(average group) and 7.65cm at 13(late group). In early group, because. PHV age came too early, it was difficult to find exact adolescence spurt period. In early group, the adolescence spurt period is considered to come at about age 7 to 9. In average group, at 9 to 11 and at 12 to 13 in late group. Especially, spurt of late group was remarkable. 4. When the growth amount of PA, before PA and after PA was compared, growth amount of PA in all three groups was about 20%. In early group, growth amount of APV tended to be large and in late group, that of APV tended to be large and in late group, that of BPV was large. In average group, growth amount of BPV was larger than that of APV. 5. For the purpose of comparing total height growth amount of these groups at age 18, the height growth was assumed to be over. And then, the difference of three groups was studied but it's not significant. 6. Although the difference between height growth and family environment, dietary habits, exercise, disease history in these three groups was investigated, only the income was significant. The significance of all the other factors was not approved. 7. When menarcheal age was compared with PA, generally we know menarche appeared after 1∼2 years of PHV age. But in case of early group, the difference between PHV age and menarcheal age was 5.34 years. In average group, 2.45 years and 0.82 years in late group.

• Journal of the Korea Society of Computer and Information
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• v.13 no.6
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• pp.13-24
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• 2008

The multi robot operation technique has emerged as one of the most important research subjects that focus on minimizing redundancy in space exploration and maximizing the efficiency of operation. For an efficient operation of the multi robot systems, the movement of each Single robot in the multi robot systems should be properly observed and controlled. This paper suggests Multi Robot Management System to minimize redundancy in space exploration by assigning exploration space to each robot efficiently to take advantage of the RFID. Also, this paper has suggested fault tolerance technique that detects disable Single robot and substitute it by activated Single robot in order to ensure overall exploration and improve efficiency of exploration. Proposed system overcomes previous fault that it is difficult for central server to detect exact position of robot by using RFID system and Home Robot. Designated Home robot manages each Single robot efficiently and assigns the best suited space to Single robot by using RFID Tag Information. Proposed multi robot management system uses RFID for space assignment, Localization and Mapping efficiently and not only maximizes the efficiency of operation, but also ensures reliability by supporting fault-tolerance, compared with Single robot system. Also, through simulation, this paper proves efficiency of spending time and redundancy rates between multi robot management applied by proposed system and not applied by proposed system.

• Proceedings of the Safety Management and Science Conference
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• 2011.04a
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• pp.319-328
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• 2011

It has been very important to have an exact evaluation for risk factors in order to prevent MSDs(Musculoskeletal Disorders). However, most MSDs evaluation checklists have always been some problems of possibilities associated with subjective evaluation. Therefore, this study tried to conduct a sort of sensitivity analysis on three major evaluation checklists(OWAS, RULA, REBA). Specifically, major subjects in the study consisted of three parts as follows; comparison of the results between experienced and inexperienced subjects, analysis for the consistency of the results in terms of different evaluation times. The results of the study were summarized as follows; 1) There was statistically significant difference of the results by RULA and by REBA between experienced and inexperienced subjects. This might due to the fact that experienced subjects have had better ability to detect the bad working posture during evaluation. However, the results by OWAS did not give any significantly different results between experienced and inexperienced subjects., 2) All three checklists showed significantly different results in terms of different evaluation times. Further study on this subject would eventually provide a sophisticated evaluating guidelines for MSDs regarding determination of subject-specific evaluation, identification of repetitive number of evaluations for stable results for each checklist, determination of job-specific evaluation methods, and so on.

• Restorative Dentistry and Endodontics
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• v.26 no.4
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• pp.296-306
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• 2001

The purpose of this study was to observe the effect of dexamethasone and osteogenic protein-1(BMP-7) on bone, cementum and periodontal tissue regeneration. A total of 60 Sprague-Dawley white female mice were selected and beta-APN was used for five days to extract the maxillary first molar a traumatically. After the extraction of the teeth, the mesiobuccal root canal was filled with Caviton$^{\circledR}$. The teeth were etched with citric acid for 1 min and coated with one of four different experimental solutions : DEX(500nM/ml), DEX(1000nM/ml), OP-1(100$\mu\textrm{g}$/ml) and OP-1(500$\mu\textrm{g}$/ml) for three minutes depending on the group. All teeth were then replanted under microscope. All replantation procedures were done within 30 minutes. Teeth that were replanted after 30 minutes of bench dry only was used as positive control. All animals were sacrificed at 3 weeks following replantation and histologic observtion was done. The results were as follows ; 1. Active root resorption rate was decreased by the order of OP-1(500$\mu\textrm{g}$/ml), DEX(1000nM/ml), OP-1(100$\mu\textrm{g}$/ml), and DEX(500nM/ml). There was statistically less root resorption in OP-1 (500$\mu\textrm{g}$/ml) and DEX(1000nM/ml) group(P<0.05). 2. The group with higher concentration of dexamethasone(1000nM/ml) had statistically more bone union compared to positive control group(P<0.05),but there were no significant differences among four experimental groups. 3. OP-1(500$\mu\textrm{g}$/ml) and DEX(1000nM/ml) groups showed less degree of inflammation compared to the OP-1(100$\mu\textrm{g}$/ml). DEX(500nM/ml), and positive control group (P<0.05). In conclusion, the group with higher concentration of OP-1 had the best results on root resorption, bone ankylosis and anti-inflammatory effects compared to the other experimental groups, but a long-term study is also necessary to evaluate the exact pharmacological effects of the drugs in the future.

• Korean Journal of Food Science and Technology
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• v.33 no.1
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• pp.28-32
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• 2001

Major sensory characteristic components-salty(NaCl), sweet(free sugars), palatable tastes(MSG, IMP, GMP) and related components-in soup base of commercial ramyons(25 ramyons, 11 bowl ramyons) were investigated to estimate their use level. $Na^+$ content($18.73{\pm}3.18%$ in ramyons and $17.62{\pm}1.92%$ in bowl ramyons) was determined by IC so that NaCl values (20.90% in ramyons and 18.16% in bowl ramyons) could be calculated from it. And from the assayed results of glutamic acid($10.50{\pm}3.78%$ in ramyons and $10.47{\pm}1.68%$ in bowl ramyons) by LC, MSG values were 12.08% in ramyons and 12.04% in bowl ramyons. GMP and IMP contents were $0.15{\pm}0.06%$, $0.20{\pm}0.11%$ in ramyons and $0.14{\pm}0.03%$, $0.18{\pm}0.05%$ in bowl ramyons, respectively. In addition, free sugars contained in ramyons such as sucrose, glucose and fructose were also analyzed by LC. In order to compare the sweetness, the free sugars were multiplied by conversion factor(sucrose 1, glucose 0.7, fructose 1.1), which showed $19.85{\pm}5.68%$ in ramyons and $18.02{\pm}7.82%$ in bowl ramyons. Therefore it is concluded that the analytical method of $Na^+$, glutamic acid and free sugars can be used as a simple and exact technique for the determination of NaCl, MSG and sweetness of ramyons.

• International Commerce and Information Review
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• v.15 no.4
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• pp.341-366
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• 2013

The term, Mittelstand, has no exact english translation for the definition, but, today, Mittelstand refers to small and medium-sized enterprises(SME), mostly family-owned firms in Germany. The Mittelstand is called the backbone of the German economy because it drove the economic miracle after World War II. During the global recession and the euro zone's debt crisis in recent years, in which european businesses have faced the near-collapse of competitiveness particularly in manufacturing, the German exports are booming and exceeded exports of China in 2012. Most importantly, the Germany economic performance has been widely attributed to the strength of the Mittelstand. Many of countries, even some leading public companies are seeking to emulate the success of the Mittelstand. Investors evaluate that many of Germany's investable "hidden champions" are Mittelstand companies. The purpose of this study is to present some of answers to the following questions: Firstly, what makes the German Mittelstand so successful? Secondly, what does the success of the German Mittelstand mean for the Korean SMEs in global competitiveness? Thirdly, what Korean government has to do improve the global competitiveness of the Korean SMEs? Some discussions in this study mention the managerial implications for Korean exporting SMEs particularly in manufacturing. Several factors that account for the success of the German Mittelstand are technological excellence and the tradition of family-owned management, concentration on niche market and globalization, and institutional supports. There are some of important lessons to be learned from the German Mittelstand. If the purposes of Korean SMEs want to remain in the sustainable competitive advantage and withstand unforeseen economic turbulences in the future, they must be able to meet the followings: 1) Technology that meets the global standard or exceeding it 2) Competitiveness in price in the global market 3) Active involvement in the globalization process, utilizing various entry modes Innovative products at globally competitive price are a crucial point for Korean exporting SMEs to achieve their competitive edge over others in the target markets abroad. It is time for Korean SMEs to cultivate a core competence in manufacturing in order to position Korea as a global manufacturing hub with SMEs leading.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.11
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• pp.180-187
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• 2013

The dinger in solar generation is the amount of sunlight which the solar cells absorb. Various types of solar trackers, which rotate themselves in order to make the solar cells face the sun as much as possible, have been developed, and especially the method of tracking with two axes has greatly contributed in increasing the generation amount at work sites. Among theses 2-axis solar trackers, the inclination-dependent 2-axis solar tracker are widely utilized for its advantages of requiring less initial investment and easy maintenance due to a solid structure. However, the drawback is that the generation efficiency is relatively low because of the structural restriction that limits the rotation angle, thus making it less efficient when tracking the sun. This paper proposes a method to increase the generation efficiency of the inclination-dependent 2-axis solar tracker. It also contains the derived equations needed for precise controlling along with a method to keep tracking with the other axis even when one has reached its angle limit. To confirm that the proposed method increases the amount of incidence onto the solar cells, formulas needed for operation on the proposed method and tracking the exact position of the sun are derived, and applying this to the quarterly data of Korea Astronomy and Space Science Institute it shows maximum over 11.1% more incidence compared to existing methods.