• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.243-244
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• 2022

In this paper, experiments were conducted on signal amplification of polymer capsules for application to Ground Penetrating Radar so as to enable real-time monitoring of polymer capsules inside concrete using the Morphology Dependent Resonance phenomenon. A TEM CELL and a vector network analyzer were used to analyze the difference in resonance frequency depending on the material of the sphere and the presence or absence of fracture. In order to manufacture a capsule of a size that can be measured using millimeter waves used in GPR, we manufactured a capsule with a 3D printer and analyzed the effects of the presence or absence of coating and the size of the capsule on the resonance frequency. Resonant frequency or signal amplification is more affected by diameter than coating. The capsule showing the highest amplification is the resin-coated 50 mm diameter capsule with a 316-fold increase and the lowest capsule is the uncoated 10 mm diameter capsule with a signal amplification of 11.9 times. These results demonstrate the potential of GPR to measure the position and state of self-healing capsules, which are small-sized polymers, in real time using millimeter waves.

• The Journal of the Acoustical Society of Korea
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• v.26 no.1
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• pp.48-54
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• 2007

In this paper we have implemented a 3-D PL (Position Location) system to estimate the 3-dimensional position of a moving object in underwater environments. In this research, we let four sensors fixed in different Positions and moving sensorsto communicate with each other to find the 3-dementianal positions for both the fixed and moving objects. Using this we were also able to control the moving object remotely. When finding the position, we calculated the norm of the Jacobian matrix every iteration in the Newton algorithm. Also by using a different initial value for calculating the solution when the norm became higher than the critical value and the solution from the inverse matrix became unstable, we could find a more reliable position for the moving object. The proposed algorithm was used in implementing a DSP system capable of real-time position location. To verify the performance, experiments were done in a water tank. As a result we could see that our system could located the position of an object every 2 seconds with a error range of 5cm.

• Archives of Craniofacial Surgery
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• v.25 no.5
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• pp.209-216
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• 2024

Craniofacial surgery requires comprehensive anatomical knowledge of the head and neck to ensure patient safety and surgical precision. Over recent decades, there have been significant advancements in imaging techniques and the development of real-time surgical navigation systems. Intraoperative navigation technology aligns surgical instruments with imaging-derived information on patient anatomy, enabling surgeons to closely follow preoperative plans. This system functions as a radiologic map, improving the accuracy of instrument placement and minimizing surgical complications. The introduction of first-generation navigation systems in the early 1990s revolutionized surgical procedures by enabling real-time tracking of instruments using preoperative imaging. Initially utilized in neurosurgery, intraoperative navigation has since become standard practice in otolaryngology, cranio-maxillofacial surgery, and orthopedics. Since the 2000s, second-generation navigation systems have been developed to meet the growing demand for precision across various surgical specialties. The adoption of these systems in craniofacial surgery has been slower, but their use is increasing, particularly in procedures such as foreign body removal, facial bone fracture reconstruction, tumor resection, and craniofacial reconstruction and implantation. In Korea, insurance coverage for navigation in craniofacial surgery began in 2021, and new medical technologies for orbital wall fracture treatment were approved in August 2022. These technologies have only recently become clinically available, but are expected to play an increasingly important role in craniofacial surgery. Intraoperative navigation enhances operative insight, improves target localization, and increases surgical safety. Although these systems have a steep learning curve and initially prolong surgery, efficiency improves with experience. Calibration issues, registration errors, and soft tissue deformation can introduce inaccuracies. Nonetheless, navigation technology is evolving, and the integration of intraoperative computed tomography data holds promise for further enhancements of surgical accuracy. This paper discusses the various types and applications of navigation employed in craniofacial surgery, highlighting their benefits and limitations.

• Journal of Communications and Networks
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• v.18 no.5
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• pp.837-845
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• 2016

Providing a customer with tailored location-based services (LBSs) is a fundamental problem. For location-estimation techniques with radio-based measurements, LBS applications are widely available for mobile devices (MDs), such as smartphones, enabling users to run multi-task applications. LBS information not only enables obtaining the current location of an MD but also provides real-time push-pull communication service. For indoor environments, localization technologies based on radio frequency (RF) pattern-matching approaches are accurate and commonly used. However, to survey radio information for pattern-matching approaches, a considerable amount of time and work is spent in indoor environments. Consequently, in order to reduce the system-deployment cost and computing complexity, this article proposes an indoor positioning approach, which involves using Asus Xtion to facilitate capturing RF signals during an offline site survey. The depth information obtained using Asus Xtion is utilized to estimate the locations and predict the received signal strength (RF information) at uncertain locations. The proposed approach effectively reduces not only the time and work costs but also the computing complexity involved in determining the orientation and RF during the online positioning phase by estimating the user's location by using a smartphone. The experimental results demonstrated that more than 78% of time was saved, and the number of samples acquired using the proposed method during the offline phase was twice as much as that acquired using the conventional method. For the online phase, the location estimates have error distances of less than 2.67 m. Therefore, the proposed approach is beneficial for use in various LBS applications.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.36 no.5
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• pp.219-223
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• 2014

During surgical procedures, unexpected material, including surgical instruments and tissue segments, may get lost in the surgical field. Most of these should be immediately removed to prevent further complications, such as vital organ irritation, infection, and inflammatory pseudo-tumor formation. However, it is not always easy to define the exact location of the foreign body, especially if the item is very small and/or it is embedded in the soft tissue of the head and neck region. Intraoperative real-time radiological imaging with C-arm fluoroscopy can be useful to trace the three-dimensional location of small and embedded foreign bodies in the oral and maxillofacial area. We describe an unusual case of an embedded micro-screw in the intrinsic tongue muscle that had been dropped into the sublingual space during a lower alveolar bone graft procedure. The lost foreign body was accurately identified with C-arm fluoroscopy and safely removed without any further complications.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.7
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• pp.769-776
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• 2011

In order to cope with the requirements of smaller patterns, larger surfaces and lower costs in the fields of displays, optics and energy, greater attentions is now being paid to the development of micro-pattern machining technology. Compared with flat molds, roll molds have the advantages of short delivery, ease of manufacturing larger surfaces, and continuous molding. This paper presents the state-of-the-art of the micro pattern machining technology on the roll molds and introduces some research results on the machining process technology. The copper and nickel-phosphorous-alloy plating process, machining process technology for uniform micro patterns. micro cutting simulation and the real time monitoring system for micro machining are summarized. The developed technologies have led the complete localization of the prism sheets and will be applied to the direct forming process with succeeding research & development.

• Computers and Concrete
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• v.25 no.1
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• pp.15-27
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• 2020

During the past decades, the application of acoustic emission techniques (AET) through the diagnosis and monitoring of the fracture process in materials has been attracting considerable attention. AET proved to be operative among the other non-destructive testing methods for various reasons including their practicality and cost-effectiveness. Concrete and rock structures often demand thorough and real-time assessment to predict and prevent their damage nucleation and evolution. This paper presents an overview of the work carried out on the use of AE as a monitoring technique to form a comprehensive insight into its potential application in brittle materials. Reported properties in this study are crack growth behavior, localization, damage evolution, dynamic character and structures monitoring. This literature review provides practicing engineers and researchers with the main AE procedures to follow when examining the possibility of failure in civil/resource structures that rely on brittle materials.

• The Korean Journal of Physiology and Pharmacology
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• v.12 no.4
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• pp.149-153
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• 2008

Endothelin-1 (ET-1) is unequivocally elevated in the kidney with ischemic acute renal failure (ARF), whereas ET receptors ($ET_AR$ and $ET_BR$) are variably expressed. Although renal functional and structural changes are similar between ischemic and nephrotoxic ARF, there are few reports on the alteration in the ET system in nephrotoxic ARF. This study was, therefore, undertaken to investigate changes in renal expression of ET-l and its receptors in nephrotoxic ARF induced by cisplatin. Mice were intraperitoneally injected with 16 mg of cisplatin/kg at a single dose, and the expression of mRNA and protein was then quantified by real-time RT-PCR and Western blot, respectively. Immunohistochemistry was conducted for localization. Three days after treatment, ET-1 transcript in cisplatin-treated mice was thirteen times higher than that in controls, whereas ET-1 peptide was increased by 1.5-fold. Cisplatin caused a 2-fold increase in the levels of ETAR mRNA and protein. Most of the increased immunoreactive ET-1 and ETAR were localized in damaged tubules. Neither the expression of ETBR mRNA nor the abundance and immunoreactive level of ETBR protein were changed. The findings suggest that the individual components of the renal ET system are differentially regulated in cisplatin-induced nephrotoxic ARF.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.9
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• pp.2120-2126
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• 2010

This paper aims to realize the location tracking system using the Zigbee in the wireless sensor network. The wireless sensor network offers the user-oriented location tracking service in the ubiquitous environment. The location tracking service can track the location of an object or a person and provides it. The location tracking system realized in this paper can be used inside or outside without any black-out areas to measure the location of the moving nodes. In tracking inside the RSSI signals use and in tracking outside will connect with the GPS signals to track the location. Also, by using Zigbee, the wireless sensor network environment was established and by obtaining the location of the moving nodes, the real-time tracking is possible.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.250-255
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• 2005

For navigation of a service robot, mapping and localization are very important. To estimate the robot pose, the map of the environment is required and it can be built by exploration or SLAM. Exploration is the fundamental task of guiding a robot autonomously during mapping such that it covers the entire environment with its sensors. In this paper, an efficient exploration scheme based on the position probability of the end nodes of a topological map is proposed. In this scheme, a topological map is constructed in real time using the thinning-based approach. The robot then updates the position probability of each end node maintaining its position at the current location based on the Bayesian update rule using the range data. From this probability, the robot can determine whether or not it needs to visit the specific end node to examine the environment around this node. Various experiments show that the proposed exploration scheme can perform exploration more efficiently than other schemes in that, in most cases, exploration for the entire environment can be completed without directly visiting everywhere in the environment.