• Journal of Ship and Ocean Technology
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• v.11 no.1
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• pp.1-10
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• 2007

This study introduces the development of robot fish ROFI 1.1. Today, robot fish is one of strong candidates for next-generation UUV. The present paper describes the design, manufacturing, and operation tests of the robot fish developed at Seoul National University. The very first robot fish in Korea, ROFI 1.1 is operated by a wireless remote controller. Its overall length is 680mm, and weight is 8.8kg. The fore body contains main mechanical and electrical systems and is covered by a FRP skin. The aft body has a mechanical bone system that mimics fish bones, and its skin is made of flexible silicon sponge to allow elastic motion for propulsion. It is found that this mechanical system creates effective and realistic fish-like swimming mode. It is observed that the normal and maximum advancing speeds of ROFI 1.1 are about 1 and 2 m/sec, and the turning radius is between $0.7{\sim}2.5m$, depending on the turning mechanism.

• Elastomers and Composites
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• v.58 no.4
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• pp.173-178
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• 2023

Recently, there has been a significant focus on the development of flexible and stretchable sensors, driven by advancements in electronic devices and the robotics industry. Among these sensors, tactile sensors stand out as the most actively researched, playing a crucial role in facilitating interaction between humans and electronic devices, particularly in robotics and medical applications. This study specifically involves the manufacturing of a capacitive tactile sensor using a relatively straightforward process and sensor structure. Natural rubber and Nitrile butadiene rubber, commonly employed in the rubber industry, were utilized. The dielectric material in the manufactured tactile sensor possesses a porous structure. Notably, the resulting tactile sensor demonstrated excellent sensitivity, approximately 1%/kPa, and exhibited the capability to detect pressures up to 212 kPa.

• Advances in aircraft and spacecraft science
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• v.1 no.3
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• pp.331-351
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• 2014

The paper presents the development of numerical models referred to a morphing actuated aileron. The structural solution adopted consists of an internal part made of a composite chiral honeycomb that bears a flexible skin with an adequate combination of flexural stiffness and in-plane compliance. The identification of such structural frame makes possible an investigation of different actuation concepts based on diffused and discrete actuators installed in the skin or in the skin-core connection. An efficient approach is presented for the development of aeroelastic condensed models of the aileron, which are used in sensitivity studies and optimization processes. The aerodynamic performances and the energy required to actuate the morphing surface are evaluated and the definition of a general energetic performance index makes also possible a comparison with a rigid aileron. The results show that the morphing system can exploit the fluid-structure interaction in order to reduce the actuation energy and to attain considerable variations in the lift coefficient of the airfoil.

• Geotechnical Engineering
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• v.9 no.4
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• pp.45-54
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• 1993

In this paper, the behaviors of reinforced earth retaining walls according to material properties of reinforcement were performed through the centrifuge model tests. Skin element was used flexible aluminum plate in the process of tests. And reinforcements were used with aluminum foil strips and non -woven polyester sheets. As a result of it, model retaining wall utilizing non-woven polyester sheets than aluminum foil strips was supported at high stress level, and maximum horizontal displacement value of skin element was 0.6H height at model walls. In the other hand, coefficient relation diagram for evaluation of horizontal displacement according to skin element location was proposed using test results.

• Archives of Craniofacial Surgery
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• v.20 no.5
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• pp.319-323
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• 2019

Cochlear implant extrusion, which is a common complication of cochlear implants, is generally repaired by a well visualized soft-tissue flap. A 61-year-old female patient with a medical history of schizophrenia who had a skin ulcer that caused cochlear implant extrusion, but that would be a stronger statement was referred to our department for removal of the implant and reconstruction of the resultant scalp defect. Accordingly, the broad defect was covered via rotation of a temporoparietal fascia flap (TPFF) using the superficial temporal artery, with the pedicle in the preauricular region as the pivot point. Coverage of TPFF was achieved with a split-thickness skin graft using the scalp as the donor site, which led to a quick recovery after the operation and satisfactory results in terms of aesthetics. This case suggests that a TPFF might be used as a flexible flap with low donor site morbidity for reconstructing cases of cochlear implant extrusion accompanied by a large full-layer scalp defect.

• Journal of the Korean Society of Radiology
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• v.14 no.6
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• pp.841-848
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• 2020

In the field of radiation therapy using photon beams and electron beams, since each patient has a different sensitivity to radiation, skin side effects may occur even at the same dose. Therefore, if there is a risk of excessive dose to the skin, a dosimeter is attached to verify whether the correct dose is being investigated. However, since the skin dosimeter checks the attachment site visually by measuring a point dose, it is difficult to confirm an accurate dose distribution. As a result, the measurement and simulation errors of the material HgI₂ in the 6 MV photon beam were 3.73% and 5.24%, respectively, at the minimum thickness of 25 ㎛, and the material PbI₂ was 4.73% and 5.65%, respectively. On the other hand, as a result of the 6 MeV electron beam, the measurement and simulation errors of the material HgI₂ were 1.35% and 1.12%, respectively, at a minimum thickness of 25 ㎛, and the material PbI₂ showed relatively low attenuation error, 1.67% and 1.20%, respectively. Therefore, it was evaluated that the thickness of the photon beam within 25 ㎛ and the electron beam within 100 ㎛ is suitable to have a reduction rate error within 5%. This study presents a new research direction for a flexible dosimeter attached to the human body that is required in clinical practice and the construction conditions of a future skin dosimeter.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.7
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• pp.601-608
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• 2015

The static aeroelastic analysis and optimization of flexible wings are conducted for steady state conditions while both aerodynamic and structural parameters can be used as optimization variables. The system of multidisciplinary design optimization as a robust methodology to couple commercial codes for a static aeroelastic optimization purpose to yield a convenient adaptation to engineering applications is developed. Aspect ratio, taper ratio, sweepback angle are chosen as optimization variables and the skin thickness of the wing. The real-coded adaptive range multi-objective genetic algorithm code, which represents the global multi-objective optimization algorithm, was used to control the optimization process. The support vector regression(SVR) is applied for optimization, in order to reduce the time of computation. For this multi-objective design optimization problem, numerical results show that several useful Pareto optimal designs exist for the flexible wing.

• Smart Structures and Systems
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• v.8 no.1
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• pp.139-155
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• 2011

Polymeric thin-film assemblies whose bulk electrical conductivity and mechanical performance have been enhanced by single-walled carbon nanotubes are proposed for measuring strain and corrosion activity in metallic structural systems. Similar to the dermatological system found in animals, the proposed self-sensing thin-film assembly supports spatial strain and pH sensing via localized changes in electrical conductivity. Specifically, electrical impedance tomography (EIT) is used to create detailed mappings of film conductivity over its complete surface area using electrical measurements taken at the film boundary. While EIT is a powerful means of mapping the sensing skin's spatial response, it requires a data acquisition system capable of taking electrical impedance measurements on a large number of electrodes. A low-cost wireless impedance analyzer is proposed to fully automate EIT data acquisition. The key attribute of the device is a flexible sinusoidal waveform generator capable of generating regulated current signals with frequencies from near-DC to 20 MHz. Furthermore, a multiplexed sensing interface offers 32 addressable channels from which voltage measurements can be made. A wireless interface is included to eliminate the cumbersome wiring often required for data acquisition in a structure. The functionality of the wireless impedance analyzer is illustrated on an experimental setup with the system used for automated acquisition of electrical impedance measurements taken on the boundary of a bio-inspired sensing skin recently proposed for structural health monitoring.

• Journal of Internet Computing and Services
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• v.10 no.4
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• pp.25-33
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• 2009

In the paper, we proposed a new system to retrieve 3D wrinkle data based on stereo images. Usually, 3D reconstruction based on stereo images or video is very popular and it is the research focus, which has been applied for culture heritage, building and other scene. The target is object measurement, the scene depth calculation and 3D data obtained. There are several challenges in our research. First, it is hard to take the full information wrinkle images by cameras because of light influence, skin with non-rigid object and camera performance. We design a particular computer vision system to take winkle images with a long length camera lens. Second, it is difficult to get the dense stereo data because of the hard skin texture image segmentation and corner detection. We focus on semi-dense stereo matching algorithm for the wrinkle depth. Compared with the 3D scanner, our system is much cheaper and compared with the physical modeling based method, our system is more flexible with high performance.

• BMB Reports
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• v.40 no.2
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• pp.261-269
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• 2007

The structure and dynamics of a 37-residue antimicrobial peptide gaegurin 4 (GGN4) isolated from the skin of the native Korean frog, Rana rugosa, was determined in SDS micelles by NMR spectroscopy. The solution structure of the peptide in SDS micelles was determined from 352 NOE-derived distance constraints and 22 backbone torsion angle constraints. Dynamic properties for the amide backbone were characterized by $^1H-^{15}N $heteronuclear NOE experiments. The structural study revealed two amphipathic helices spanning residues 2-10 and 16-32 and that the helices were connected by a flexible loop. An intraresidue disulfide bridge was formed between residues Cys31 and Cys37 near the C-terminus. The loop region (11-15) connecting the two helices are were slightly more flexible than these helices themselves. From the fact that since there is no contact NOEs between two helices, it is implied that the GGN4 peptide shows an independent motion of both helices which has an angle of about $ 60^{\circ}-120^{\circ}$ from each other.