• The Mathematical Education
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• v.43 no.2
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• pp.139-149
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• 2004

This study was initiated by the idea to help students to be more ideally educated following the 7th curriculum that seeks the proactive students along with creativity for the 21st century. Mind-map was the main tool throughout the study and this was performed to find answers for the following questions : 1) to examine how students' drawing a mind-map affects their mathematical tendency or emotional aspects (motivation for study, interest, etc); 2) to investigate the types and characteristics of mind-maps that students draw; 3) to analyze advantages and obstacles that they experience during the process of drawing a mind-map and provide some suggestions for overcoming them. The research shows that students were highly motivated by the drawing a mind-map. There are types of mind-maps: tree shape and radial shape, and each shape has its own advantages. But the more important factor for being a good mind-map is where and how each concept is located and connected. Although it is true that drawing a mind-map helped students to see the bigger structure of what they learned, but there are several hardships taken care of. The study suggests to extend the experiment to various levels of students and diverse contents.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.4
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• pp.391-395
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• 2010

In our paper, we propose an asymmetric single-tracked wheel system, and describe its structure and the method for maintaining the length of a transformable track system. And the method is reducing the gap of lengths. Therefore, we propose an efficient structure for transforming and explain motions with kinematics. Our transformable shape single-tracked mobile system has an advantage to overcome an obstacle or stairs by the variable arms in the single unity track system. But we will make the variable shape of tracked system get a drive that has a force to stand against a wall. In this case, we can consider this system to a rigid body and have a notice that this single tracked system is able to get vary shape with the variable arm angle. Considering forces balance along x-axis and y-axis, and moments balance around the center of the mass we have. If this rigid body is standing against a wall and doesn't put in motion, the force of flat ground and the rigid body sets an equal by a friction. In the same way, the force of a wall and the rigid sets an equal by a friction.

• The Journal of Korea Robotics Society
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• v.19 no.1
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• pp.53-57
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• 2024

A hopping robot can move through a confined environment while overcoming obstacles. To create a small hopping robot, it must be able to generate a large amount of energy and release it at the same time. However, due to the small size of the robot, there is a limit to the size of the actuator that can be used, so it is mainly used to collect energy in an elastic element and release it at once. In this paper, we propose a small hopping robot with a simplified design by removing ancillary parts and enabling continuous hopping using only a small actuator based on a direct-drive method. In addition, repeated actuation over the rated voltage can cause thermal breakdown of the actuator. To check the safety of the actuator at high voltage, we perform modeling to predict the temperature of the actuator and verify the accuracy of the modeling through experiments.

• Korean Journal of Construction Engineering and Management
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• v.3 no.1 s.9
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• pp.107-114
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• 2002

Recently, a few major construction companies in Korea have a growing interests to the risk management system, and they are trying to apply it to their construction projects. However, the existing methodologies to be applied to the foreign public projects are not proper to the construction environments due to its adaptabilities, that has one time process and heavily depends on personal judgement. The purpose of this paper is to propose a risk response process in consideration of the residual risks, which would be more adaptable and practical in the construction environment, overcoming the current obstacles to be mentioned above. This process has systematic repeat process until the residual risks go down to the risk thresholds based on the efficiency of specific response strategy.

• Current Optics and Photonics
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• v.5 no.3
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• pp.213-219
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• 2021

We describe a single-channel rubidium (Rb) radio-frequency atomic magnetometer (RFAM) as a receiver that takes magnetic signal resonating with Zeeman splitting of the ground state of Rb. We optimize the performance of the RFAM by recording the response signal and signal-to-noise ratio (SNR) in various parameters and obtain a noise level of 159 $fT{\sqrt{Hz}}$ around 30 kHz. When a resonant radiofrequency magnetic field with a peak amplitude of 8.0 nT is applied, the bandwidth and signal-to-noise ratio are about 650 Hz and 88 dB, respectively. It is a good agreement that RFAM using alkali atoms is suitable for receiving signals in the very low frequency (VLF) carrier band, ranging from 3 kHz to 30 kHz. This study shows the new capabilities of the RFAM in communications applications based on magnetic signals with the VLF carrier band. Such communication can be expected to expand the communication space by overcoming obstacles through the high magnetic sensitive RFAM.

• Wind and Structures
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• v.36 no.2
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• pp.75-90
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• 2023

Turbulent wind flow over hilly terrains has been extensively investigated in the scientific literature and main findings have been included in technical standards. In particular, turbulent wind flow over nominally two-dimensional hills is often adopted as a benchmark to investigate wind turbine siting, estimate wind loading, and dispersion of particles transported by the wind, such as atmospheric pollutants, wind-driven rain, windblown snow. Windblown sand transport affects human-built structures and natural ecosystems in sandy desert and coastal regions, such as transport infrastructures and coastal sand dunes. Windblown sand transport taking place around any kind of obstacle is rarely in equilibrium conditions. As a result, the modelling of windblown sand transport over complex orographies is fundamental, even if seldomly investigated. In this study, the authors present a wind-sand tunnel test campaign carried out on a nominally two-dimensional sinusoidal hill. A first test is carried out on a flat sand fetch without any obstacle to assess sand transport in open field conditions. Then, a second test is carried out on the hill model to assess the sand flux overcoming the hill and the morphodynamic evolution of the sand sedimenting over its upwind slope. Finally, obtained results are condensed into a dimensionless parameter describing its sedimentation capability and compared with values resulting from other nominally two-dimensional obstacles from the literature.

• Convergence Security Journal
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• v.23 no.5
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• pp.173-179
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• 2023

The 4th Industrial Revolution technology has emerged as a solution to build a hyper-connected, super-intelligent network-oriented operational environment, overcoming the obstacles of reducing troops and defense budgets facing the current military. However, the overall risk management, including the increase in complexity of the latest inform ation technology and the verification of the impact with the existing information system, is insufficient, leading to serious threats to system integrity and availability, or negatively affecting interoperability between systems. It can be inhibited. In this paper, we suggest cyber threat response strategies for our military to prepare for cyber threats by examining information security risk management in the United States in order to protect military information assets from cyber threats that may arise due to the advancement of information technology.

• Journal of the Korea Society of Computer and Information
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• v.12 no.1 s.45
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• pp.243-252
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• 2007

In recent years, there has been a growing concern about enterprise resource planning (ERP) implementation in small and medium-sized enterprises (SMEs). In this study, we investigate the relationship among ERP software qualify, vendor support, user information satisfaction. and performance of ERP implementation. The empirical findings of this paper will allow SMEs to identify the importance of relationships with vendors and software itself for the successful implementation of ERP systems. The results provide a useful basis for the SMEs which have limited information capability to focus their attention on the software quality and vendor support in overcoming difficulties and obstacles facing the ERP implementation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.400-413
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• 2017

It is necessary for inmates released from prison to recover their career capital in order to function normally in society. Failure to adapt to the society may not only make them unhappy but could also aggravate social safety nets. Therefore, it is critical to examine the recovery of career capital. For this study, we conducted in-depth interviews of 10 rehabilitation recipients who were supported by Korea Rehabilitation Agency. For qualitative analysis, several career topics were analyzed, such as obstacles in recovering career capital, efforts in overcoming these obstacles, what is helpful for them to overcome the obstacles and what is required for them to adapt to the career life and others. Analysis results found that the rehabilitation beneficiaries suffered loses to their career capital due to their incarceration, suffered from the loss of pride and became despondent in the process of recovery of career capital due to the negative social perception toward their social self, fear of social stigma and devaluation of themselves. In addition, the fear of possible negative evaluation was a critical factor in making their social activities more challenging. Conversely, it was found that social support in the recovery process of career capital has a positive effect. In particular, emotional support from spouses, employers, family members and friends are the most positive factors. Concerning efforts at adapting to careers, it was found that an active, leading and positive attitude toward the career were critical, showing that positive evaluation and recognition in family and social relations and the experience of success in the career were positive elements in enhancing a sense of pride. In summary, it was found that in the recovery process of career capital, dysfunctional beliefs had a negative effect, while social support had a positive effect, on the recovery of career capital.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.6
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• pp.558-565
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• 2011

Various robot platforms have been designed and developed to perform given tasks in a hazardous environment for surveillance, reconnaissance, search and rescue, etc. We considered a terrain-adaptive and transformable hybrid robot platform that is equipped with rapid navigation capability on flat floors and good performance in overcoming stairs or obstacles. The navigation mode transition is determined and implemented by adaptive driving mode control of the mobile robot. In order to maximize the usability of wheel-track hybrid robot platform, we propose a terrain-adaptive and user-friendly remote controller and verify the efficiency and performance through its navigation performance experiments in real and test-bed environments.