• Journal of the Korean Society of Marine Environment & Safety
• /
• v.27 no.6
• /
• pp.846-855
• /
• 2021

Eco-friendly and renewable energy sources are actively being researched in recent times, and of shore wind power generation requires advanced design technologies in terms of increasing the capacities of wind turbines and enlarging wind turbine installation vessels (WTIVs). The WTIV ensures that the hull is situated at a height that is not affected by waves. The most important part of the WTIV is the leg structure, which must respond dynamically according to the wave, current, and wind loads. In particular, the wave load is composed of irregular waves, and it is important to know the exact dynamic response. The dynamic response analysis uses a single degree of freedom (SDOF) method, which is a simplified approach, but it is limited owing to the consideration of random waves. Therefore, in industrial practice, the time-domain analysis of random waves is based on the multi degree of freedom (MDOF) method. Although the MDOF method provides high-precision results, its data convergence is sensitive and difficult to apply owing to design complexity. Therefore, a dynamic amplification factor (DAF) estimation formula is developed in this study to express the dynamic response characteristics of random waves through time-domain analysis based on different variables. It is confirmed that the calculation time can be shortened and accuracy enhanced compared to existing MDOF methods. The developed formula will be used in the initial design of WTIVs and similar structures.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.25 no.10
• /
• pp.1173-1182
• /
• 1988

The stability, energetic efficiency and walking volume are affected by the geometric structure of legs of a walking robot. A quadruped walking robot is considered to have large stability margin among the walking robots and pantograph leg permits large walk stroke and mutually independent vertical and horizontal movements, but the kinematic characteristics are difficult to analyze. Graphical method may be useful to characterize three dimensional legged motion of the pantograph mechanism. We present the modelling method for three different quadruped robots with pantograph legs that have different joints mechanism. The modeled robots are animated by a path that is planned with respect to the center of body. In particular, graphical animation incorporates leg control to rotation and side walking and uses the window of Sun-3 system for displaying joint information.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.8 no.7
• /
• pp.1418-1423
• /
• 2004

A legged robot is friendly to human because it is resemble to human. And the robot can obtain support points freely because it has high degree of freedom for several joint as compared with a wheeled robot. Also the robot can create the relative position at desired position between support position and robot. The joint of robot cu used as manipulator. On the contrary the mechanism of robot is complicated to have many joint and moving speed is lower than wheeled robot. Also the legged robot is needed a special control not to fall on the ground because the robot is easy to vibrate when it is moving. The 4 leg structure is the minimum leg numbers not to fall and to realize safety gait continuously. A trot gait is investigated through experiments using a quadruped walking robot named TITAN-VIII.

• The Journal of the Convergence on Culture Technology
• /
• v.6 no.1
• /
• pp.23-29
• /
• 2020

Since the movements of a machine are driven by a certain principle, there is a fundamental principle that governs the movement of the machine, no matter how complex and diverse it may be. Autonomous movements are a way to avoid repetition, to approach more humane and more natural factors. That's all the more so when it comes to original movements, not cloning. So now, the dynamics of the machine are more multi-sensory by human participation. It is challenging the potential to be expressed and is gradually expanding its sphere of expression in the boundaries of fact and cloning. Theo Jansen's works have changed from period to period to adapt to different circumstances, indicating that his decades-long work has continued to evolve from early to present. The evolution's focus, among other things, can be seen as having the same source of circular motion and horizontal reciprocating motion, which are repeated from the principle of organic coupling between the parts that make up the object.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.07b
• /
• pp.631-634
• /
• 2004

The method that exists in Photodynamic Therapy uses Photosensibility drug strongly Influencing tumour accumulation together with photochemical laser effect and makes the structure of tumour be localized and become extinct. The intracavity transformation of the Nd :YAP main radiation 1079 nm was Raman converted in barium nitrate crystal and the Stokes frequency (1216 nm) was doubled using KTP or RTA crystals. The LiF or Cr:YAG crystals are used for the Q-switch. The radiation Parameters were obtained at 100 Hz pump repetition frequency. The average power at 608 nm radiation with LiF and KTP was 700 mW at multi-mode generation. The 3-6 single 10-15 ns pulses were generated during one cycle of pumping. The doubling efficiency with RTA was two times more than with KTP. The cells of Ehrlich adenocarcinoma (0.1 ml) were i.m. implanted in hind thighs of ICR white non-imbred mice. The cells were preliminarily diluted in medium 199 in the ratio of 1 to 5. HpD was intravenous administered in a dose of 10 mg/kg. The left clean-shaven hind leg was irradiated with laser light 21-27 hours after the administration of the preparation. The right non-Irradiated leg of each animal served as a control. The animals with the transplanted tumor that were not injected with HpD sewed as a control to estimate the complex effect (HpD+ irradiation). Before the administration of HpD and on 3 and 4 days after irradiation the tumor size was measured and the percent of the tumor growth inhibition was calculated. The results of animal treatments has shown high efficiency of PDT method for cancer treatment by means 0.608 m high power pulse solid state laser.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.16 no.4
• /
• pp.763-770
• /
• 2021

In this paper, in order to exclude the influence of BAN(Body Area Network) signals operating in the ISM band, the design and optimization process of an on-body microstrip patch antenna operating at 4.567 GHz is presented. The antenna for the monitoring of the lower legs with cancellous osteoporosis is designed to be lightweight and compact with improved return loss and bandwidth. The structure around the applied lower leg consisted of a five-layer dielectric plane. Taking into account losses, the complex dielectric constant of each layer is calculated using multi Cole-Cole model parameters, whereas a unipolar model is used for normal or osteoporotic cancellous bones. The return loss of the coaxial feed antenna on the phantom is -67.26 dB at 4.567 GHz, and in the case of osteoporosis, at the same frequency the return loss difference is 35.88 dB, and the resonance frequency difference is about 7 MHz.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.20 no.3
• /
• pp.126-132
• /
• 2012

Recently, pedestrian protection related research topics have been actively studied by automotive designers and engineers due to the enhanced pedestrian protecting regulations. It is required to design an energy absorbing structure, such as crumple zone that can sufficiently absorb the impact energy to reduce the leg injury when accident happens. The structure is designed by reducing the height of front end module, considering the mounting location, and investigating impact characteristics. In this paper, the concept of the crumple zone was introduced and the role of the crumple zone was investigated by analyzing the performance of upper legform impact to a bonnet leading edge test, and the design process was suggested.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.314-319
• /
• 2005

When a robot navigates in the real environment, it frequently meets various environments that can be expressed by simple geometrical shapes such as fiat floor, uneven floor, floor with obstacles, slopes, concave or convex corners, etc. Among them, the convex corner composed of two plain surfaces is the most difficult one for the robot to negotiate. In this paper, we propose a gait planning algorithm to help the robot overcome the convex environment. The trajectory of the body is derived from the maximum distance between the edge boundary of the corner and the bottom of the robot when it travels in the convex environment. Additionally, we find the relation between kinematical structure of the robot and its ability of avoiding collision. The relation is realized by considering the workspace and the best posture of the robot in the convex structure. To provide necessary information for the algorithm, we use an IR sensor attached in the leg of the robot to perceive the convex environment. The validity of the gait planning algorithm is verified through simulations and the performance is demonstrated using a quadruped walking robot, called "MRWALLSPECT III"( Multifunctional Robot for WALL inSPECTion version 3).

• Structural Engineering and Mechanics
• /
• v.16 no.3
• /
• pp.317-326
• /
• 2003

The tension leg platform (TLP) is a moored floating offshore structure whose buoyancy is more than its weight. The mooring system, known as tethers, is vulnerable to failure due to extreme (maximum and minimum) tensions. In the present study the reliability of these tethers under maximum and minimum tension (ultimate limit state) has been studied. Von-Mises failure criteria has been adopted to define the failure of a tether against maximum tension. The minimum tension failure criteria has been assumed to meet when the tethers slack due to loss of tension. First Order Reliability method (FORM) has been adopted for reliability assessment. The reliability, in terms of reliability index, and probability of failure has been obtained for twelve sea states. The probabilities of failure so obtained for different sea states have been adopted for the calculation of annual and life time probabilities of failure.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.1530-1534
• /
• 2004

This paper presents a novel bio-mimetic quadruped walking robot with a waist joint, which connects the front and the rear parts of the body. The new robot, called ELIRO-1(Eating LIzard RObot version 1), can bend its body while the legs is transferred, thereby increasing the stride and speed of the robot. The waist-jointed walking robot can move easily from side to side, which is an important feature to guarantee a larger gait stability margin than that of a conventional single rigid-body walking robot. We design the mechanical structure of the robot, which is small and light to have high movability and high degree of human friendship. In this paper, we describe characteristics of the waist joint and leg mechanism as well as the analysis using ADAMS to select appropriate actuators. In addition, a hardware and software of the controller of ELIRO-1 are described.