• Korean Journal of Applied Biomechanics
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• v.27 no.2
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• pp.141-147
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• 2017

Objective: We obtained force-displacement curves for countermovement jumps of multiple heights and examined the effect of an arm swing on changes in vertical jumping strategy. Countermovement jumps with hands on hips (Condition 1) and with an arm swing (Condition 2) were evaluated to investigate the mechanical effect of the arm movement on standing vertical jumps. We hypothesized that the ground reaction force (GRF) and/or center of mass (CoM) motion resulting from the countermovement action would significantly change depending on the use of an arm swing. Method: Eight healthy young subjects jumped straight up to five different levels ranging from approximately 10% (~25 cm) to 35% (~55 cm) of their body heights. Each subject performed five sets of jumps to five randomly ordered vertical elevations in each condition. For comparison of the two jumping strategies, the characteristics of the boundary point on the force-displacement curve, corresponding to the vertical GRF and the CoM displacement at the end of the countermovement action, were investigated to understand the role of arm movement. Results: Based on the comparison between the two conditions (with and without an arm swing), the subjects were grouped into type A and type B depending on the change observed in the boundary point across the five different jump heights. For both types (type A and type B) of vertical jumps, the initial vertical force at the start of push-off significantly changed when the subjects employed arm movement. Conclusion: The findings may imply that the jumping strategy does change with the inclusion of an arm swing, predominantly to modulate the vertical force advantage (i.e., the difference between the vertical force at the start of push-off and the body weight).

• Journal of Information Processing Systems
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• v.18 no.3
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• pp.332-343
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• 2022

To address the problems of the gravitational search algorithm (GSA) in which the population is prone to converge prematurely and fall into the local solution when solving the single-objective optimization problem, a sine map jumping gravity search algorithm based on asynchronous learning is proposed. First, a learning mechanism is introduced into the GSA. The agents keep learning from the excellent agents of the population while they are evolving, thus maintaining the memory and sharing of evolution information, addressing the algorithm's shortcoming in evolution that particle information depends on the current position information only, improving the diversity of the population, and avoiding premature convergence. Second, the sine function is used to map the change of the particle velocity into the position probability to improve the convergence accuracy. Third, the Levy flight strategy is introduced to prevent particles from falling into the local optimization. Finally, the proposed algorithm and other intelligent algorithms are simulated on 18 benchmark functions. The simulation results show that the proposed algorithm achieved improved the better performance.

• The Journal of Korea Robotics Society
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• v.8 no.2
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• pp.136-142
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• 2013

In nature, many small insects are using jumping as a survival strategy. Among them, fleas jump in a unique method. They use an elastomer, 'Resilin', an extensor muscle and a trigger muscle. By contracting the extensor muscle, the elastic energy, that makes a flea to jump, is stored in the resilin. After storing energy, the trigger muscle begins contracting and pulling the extensor muscle. When the extensor muscle crosses the rotational joint, direction of torque generated from the extensor muscle reverses, 'torque reversal mechanism'. Simultaneously, the elastic energy stored in the resilin releases rapidly and is converted into the kinetic energy. It makes a flea to jump 150 times its body length. In this paper, miniaturized jumping robot using flea-inspired catapult mechanism is presented. This mechanism is based on the 4-bar linkage and the reversal joint and is actuated by Shape Memory Alloy (SMA) coiled springs describing the flea's muscle. The robot prototype is fabricated by SCM process using glass fiber prepregs and a sheet of polyimide film. The prototype is 20mm link length, 34mm width and 2.0g weight and can jump 103cm.

• Journal of Information Science Theory and Practice
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• v.10 no.spc
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• pp.76-85
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• 2022

At the 8th National High-Performance Computing (HPC) Committee convened in 2021, the "National High-Performance Computing Innovation Strategy (draft) for the 4th Industrial Revolution Era" was deliberated and the original draft was approved. In this proposal, the Ministry of Science and ICT in KOREA announced three major plans and nine detailed projects with the vision of "Realizing the 4th industrial revolution quantum jumping by leaping into a high-performance computing powerhouse." Thereby the most important policy about national mid-term and long-term HPC development was established and called the HPC innovation strategy (hereinafter "the innovation strategy"). The three plans of the innovation strategy proposed by the government are: Strategic HPC infrastructure expansion; Secure source technologies; and Activate innovative HPC utilization. Each of the detailed projects has to be executed nationally and strategically. In this paper, we propose a strategy for the implementation of two items ("Strategic HPC infrastructure expansion" and "activate innovative HPC utilization") among these detailed plans.

• Journal of the Korean Society of Physical Medicine
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• v.4 no.1
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• pp.49-56
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• 2009

Purpose : The Purpose of this study was to investigate the effects of image training and vibration on performance of vertical jumping. Methods : Subjects was classified into two groups, which were image training group(n=20) and vibration application group(n=20). The standard methods of each intervention were image training with listening recorded indication for 5 minute and vibration with speed of $1200{\pm}200\;rpm$. Muscle strength was measured using vertical jump performance. Results : The vertical jump performance was significantly increased after image training and vibration application(p<.05), however, it was more significantly after image training(p<.05). Conclusion : This study showed that image training and vibration application were effective treatment strategy on increase of muscle strength. Therefore, it could be considered as a treatment method in the patients with musculoskeletal disease including fracture, chronic degenerative disease and disuse atrophy.

• Journal of Information Technology Services
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• v.11 no.4
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• pp.309-333
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• 2012

Recently, emergence of smart-phones and Social Networking Service(SNS) would offer the market environment changes and the opportunities for new business. For the case analysis comprehensive survey were implemented. And those data were analyzed along the research framework. The late-comer firms offered differential services, maintained creative and opened corporate culture, shoed learning capabilities which means absorption and organization of external knowledge, innovative efforts to control the insurgents than early-mover firms. When we analyze these phenomena along the developmental stages of late-comer, we can perceive that the stage of late-comers firms were moving from the "tracing the path" stage to "jumping the path" stage which means the creating capabilities were more or less enhanced and the firms become more stable in terms of business operation. In business model, early-mover firms showed clear definition for each business element, especially the revenue structure, while late-mover firms seemed unstable or unclear revenue structure.

• Korean Journal of Applied Biomechanics
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• v.19 no.1
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• pp.27-36
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• 2009

The purpose of this study was to identify effects of restricted trunk motion on the performances of the maximum vertical jump. Ten healthy males performed normal countermovement jump(NJ) and control type of countermovement jump(CJ), in which subjects were required to restrict trunk motion as much as possible. The results showed 10% decreases of jumping height in CJ compared with NJ, which is primarily due to vertical velocity at take off. NJ with trunk motion produced significantly higher GRF than RJ, especially at the early part of propulsive phase, which resulted from increased moments on hip joint. And these were considered the main factors of performance enhancement in NJ. There were no significant differences in the mechanical outputs on knee and ankle joint between NJ and RJ. With trunk motion restricted, knee joint alternatively played a main role for propulsion, which is contrary on the normal jump that hip joint was highest contributor. And restricted trunk motion resulted in the changes of coordination pattern, knee-hip extension timing compared with normal proximal-distal sequence. In conclusion these results suggest that trunk motion is effective strategy for increasing performance of vertical jumping.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.4
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• pp.277-283
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• 2017

In this study, we investigated how a jumping strategy changes with an increase in the vertical jump height for a resultant ground reaction force (GRF) vector. We expected that the resultant force vector between two sequential motion phases (i.e., countermovement and push-off) of the countermovement jump would significantly change with the vertical jump height to take advantage of the resulting supportive force (i.e., an initial push-off force larger than the body weight) through the countermovement phase. Nine healthy young subjects were instructed to jump straight up to five different height levels ranging from 191 cm to 221 cm, and the kinematic and kinetic data were obtained in regular trials. The results showed that a lower center of mass position and larger resultant force vector were clearly observed in a higher jump, implying that the countermovement strategy changed with the vertical jump height to prepare for sufficient joint deviation and obtain a force advantage for larger push-off work.

• Korean Journal of Applied Biomechanics
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• v.22 no.4
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• pp.405-411
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• 2012

The purpose of this study was to determine the effects of landing height information on landing strategy during a drop landing. Ten healthy male subjects(age: $22.1{\pm}1.9year$, height: $178.4{\pm}7.8cm$, mass: $75.3{\pm}9.4kg$) participated in this study. Each participant was asked to jump with both legs off a 40 cm high box on one of the three plates with different thickness (0 cm, 13 cm, 26 cm). In the first condition, subjects were given both cognitive and visual information about the jumping heights. In the second, they were given only cognitive information without visual one, and in the third, no information about the height was provided to subjects. (Only the data collected from the 40 cm height landing were analyzed and reported in the present study.) The results showed that landing strategies during a double-leg drop landing from 40 cm height were not significantly affected by visual and cognitive information blockages. Also, there were no statistically significant differences in landing strategies between the three conditions even though the mean differences attained in this study seemed to warrant further studies investigating the relationship between landing strategies and cognitive information.

• Journal of the military operations research society of Korea
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• v.36 no.1
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• pp.103-121
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• 2010

As a cutting edge technology intensive value-added business, the defense industry is jumping into a new engine of a national growth. Also, the defense industry export is recognized not only as the field to activate the Korean economy but also as an important field to create the national brand value. However, though the consensus on the importance of defense industry export helps achieve the remarkable performance in reality, the rate of increase in the budget for national defence is slowing down gradually, and the investment in R&D is not so big, and there are a lot of drawbacks with the management of core technology and the development of cutting edge weapon system. Accordingly, this thesis tried to find the leverage to make the structure of defense industry export work normally after analyzing the systematical structure of defense industry export to understand its characteristics. Also, through the process to make the leverage a strategy, the thesis tried to present the optimal direction of policy to join the ranks of the advanced countries in defense industry export.