• The Journal of Korea Robotics Society
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• v.13 no.2
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• pp.97-102
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• 2018

A small and lightweight crawling robots have been actively studied thanks to their outstanding mobility and maneuverability. Those robots can navigate into more confined spaces that larger robots are unable to reach or enter such as debris and caves. In this paper, we propose a milli-scale hexapedal robot based on planar linkage design. To make this possible, two necessary conditions for successful crawling are satisfied: thrust force from the ground and aerial phase while running. These conditions are achieved through a newly developed leg design. The robot has a pair of legs and each leg has three feet. Those feet alternatively moves based on 1DOF planar linkage. This linkage is installed at each side of the robot and finally the robot shows the alternating gait and aerial phase during running. As a result, the robot runs with the crawling speed of 0.9 m/s.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.2
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• pp.198-202
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• 2009

Urban Search and Rescue (USAR) involves locating, rescuing (extricating), and medically stabilizing victims trapped in confined spaces. In this paper we state the current approach to USAR, address the limitations and discuss the way for moving in rugged topography. To achieve objectives such as surveillance, reconnaissance, and rescue, it is necessary to develop a driving mechanism that can handle rugged geographical features. We propose a new type of driving mechanism for a rescue robot that has a variable shape single-track. By using a variety shapes, it can get the gain of steering and rotating and the ability to overcome stairs. In this paper, we analyzed the design parameters for making variable transform shapes and determined the specifications of the robot to enhance adaptability to stairs.

• ETRI Journal
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• v.43 no.4
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• pp.580-593
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• 2021

When operating in confined spaces or near obstacles, collision-free path planning is an essential requirement for autonomous exploration in unknown environments. This study presents an autonomous exploration technique using a carefully designed collision-free local planner. Using LiDAR range measurements, a local end-point selection method is designed, and the path is generated from the current position to the selected end-point. The generated path showed the consistent collision-free path in real-time by adopting the Euclidean signed distance field-based grid-search method. The results consistently demonstrated the safety and reliability of the proposed path-planning method. Real-world experiments are conducted in three different mines, demonstrating successful autonomous exploration flights in environment with various structural conditions. The results showed the high capability of the proposed flight autonomy framework for lightweight aerial robot systems. In addition, our drone performed an autonomous mission in the tunnel circuit competition (Phase 1) of the DARPA Subterranean Challenge.

• Korean Journal of Veterinary Service
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• v.46 no.3
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• pp.203-210
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• 2023

Breeding ducks are susceptible to fungal infections due to being bred in confined spaces for long periods. The objective of this study was to show the real state of the clinical fungal contamination of 22 duck breeding farms in Chungcheongbuk-do, South Korea. Out of the 430 carcasses obtained from the 22 duck breeding farms, 80 were diagnosed with invasive pulmonary aspergillosis (IPA). Aspergillus spp. were detected as the causative agents, including 26 cases of A. fumigatus, 35 cases of A. flavus, and 19 cases of A. terreus. The clinical lesions in the breeding ducks had circumscribed cream-and-yellow-colored plaques and/or white-to-greenish mycelium. Septate hyphae with parallel walls and dichotomous branching were observed in the histopathological lesions. AGMAg ELISA was performed to determine the overall positive rate of Aspergillus spp. in duck breeding farms. These results showed a positive rate of 58.97% for Aspergillus spp. Additionally, the positive rate increased with the age of the host.

• The Journal of Korea Robotics Society
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• v.18 no.4
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• pp.403-408
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• 2023

In this paper, we introduce the results of the development of a care robot for the safe lifting and transportation of bedridden patients with difficulty moving by themselves, especially, in medical facilities. The purpose of the developed patient transfer robot is to improve the convenience of care givers and enhance the safety and comfort of care recipients by facilitating patient lifting and patient transfer tasks by applying robot technology. In order to implement the lifting function, a hoist was designed and developed, and a sway control and rollover warning system were included in the hoist module as product differentiators. In addition, in terms of implementing the transfer function, an omnidirectional movement mechanism to improve operability in confined spaces and an active safety system to prevent collisions were developed. The function of the developed patient transfer robot was verified through performance evaluation by an authorized testing agency.

• Membrane Journal
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• v.12 no.4
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• pp.207-215
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• 2002

The hindered diffusion in confined spaces is an important phenomenon to understand in a micro-scale the filtration mechanism determined by the particle motion in membrane pores. Compared to the case of spherical colloids, both the theoretical investigations and the experiments on the hindered diffusion of polyelectrolytes is actually more difficult, due to lots of relevant parameters resulting from the complicated conformational properties of the polyelectrolyte chain. We have successfully performed the Brownian dynamics simulations upon a single polyeiectrolyte confined in a slit-like pore, where a coarse-grained bead-spring model incorporated with Debye-Huckel interaction is properly adopted. For the given sizes of both the polyelectrolyte and the pore width, the hindered diffusion coefficient decreases as the solution ionic concentration decreases. It is evident that a charge effect of the pore wall enhances the hindered diffusion of polyelectrolyte. Simulation results allow us to make sense of the diffusive transport through the micro-pore, which is restricted by the influences of the steric hindrance of polyelectrolytes as well as the electrostatic repulsion between the polyelectrolytes and pore wall.

• Journal of Navigation and Port Research
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• v.45 no.6
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• pp.366-371
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• 2021

This study suggests surface wave communication, which uses a metal surface as a medium, to provide wireless communication in the extreme environment due to surrounding metal materials on vessels. The test was conducted on a G/T 265 tons tug boat to confirm the possibility of surface wave communication between a bridge and each designated space in the ship. As a result, the transmission speed was 13Mbps on average. In a test case of the bridge via the engine room, the transmission speed was 4.3Mbps on engine running and 1.2Mbps on sailing. It overcame this by partially changing the equipment installation location. Surface wave communication in bow storage, a fully enclosed space, had 8Mbps better transmission speed than wireless communication; this confirmed the superiority of surface wave communication in confined spaces on a vessel. Additional surface wave generators were designed and applied to resolve the paint issue. It is expected to use surface wave communication to implement the new wireless solution for Maritime-IoT system on vessels.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2021.11a
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• pp.127-128
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• 2021

This study suggests surface wave communication, which uses a metal surface as a medium, to provide wireless communication in the extreme environment due to surrounding metal materials on vessels. The test was conducted on a G/T 265 tons tug boat, and to confirm the possibility of surface wave communication between a bridge and each designated space in the boat. As a result, the transmission speed was 13Mbps in average. For the test case between the bridge and the engine room, transmission speed was 4.3Mbps while the engine was on, and 1.2Mbps during sailing. It was able to be overcome by partially changing the equipment installation location. Surface wave communication in a bow storage, a fully enclosed space, had 8Mbps better transmission speed than wireless communication; this confirmed the superiority of surface wave communication in confined spaces on a vessel. Additional surface wave generators were designed and applied to resolve the paint issue. It is expected to apply surface wave communication to implement the new wireless solution on vessels.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.594-600
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• 2016

The present study numerically investigated the gas leakage characteristics in a simplified underground combined cycle power plant. The effect of obstacles near a crack location on the gas concentration in the confined space was analyzed by using the lower flammable limit (LFL) of methane gas. When the jet flow was close to the vertical walls, the longitudinal leakage distance increased by about 60% (when an obstacles was present) compared to the case without any obstacle, because these obstacles prevented transverse flows. In addition, when an air filter was installed near to the trajectory of the gas flow, the longitudinal leakage distance was similar to the distance between the crack and obstacle, whereas the transverse leakage distance increased up to 8 times compared to the case without any obstacle. As the jet flow impacts on the obstacle and changes its direction, the gas flows recirculate. Therefore, it is necessary to consider the effect of the structure and facility locations on the trajectory of the jet flow to propose an accident prevention system in confined spaces.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.4
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• pp.314-319
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• 2010

Odontogenic infections are a normally locally confined, self-limiting process that is easily treated by antibiotic therapy and local surgical treatment. However, it may spread into the surrounding tissues through a perforation of the bone, and into contiguous fascial spaces or planes like the primary or secondary fascial spaces. If the infection extends widely, it may spread into the lateral pharyngeal and retropharyngeal space. The retropharyngeal space is located posterior to the pharynx. If an odontogenic infection spreads into this space, severe life-threatening complications will occur, such as airway obstruction, mediastinitis, pericarditis, pleurisy, pulmonary abscess, aspiration pneumonia and hematogenous dissemination to the distant organs. The mortality rate of mediastinitis ranges from 35% to 50%. Therefore, a rapid evaluation and treatment are essential for treating retropharyngeal space abscesses and preventing severe complications. Recently, we encountered two cases of a retropharyngeal space abscess due to the spread of an odontogenic infection. In all patients, early diagnosis was performed by computed tomography scanning and a physical examination. All patients were treated successfully by extensive surgical and antibiotic therapy.