• Journal of Institute of Control, Robotics and Systems
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• 제19권12호
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• pp.1067-1071
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• 2013

A 3D visual sensing method using a laser structured beam is presented for robotic tracking applications in a simple and reliable manner. A cylindrical shaped laser structured beam is proposed to measure the pose and position of the target surface. When the proposed laser beam intersects on the surface along the target trajectory, an elliptic pattern is generated. Its ellipse parameters can be induced mathematically by the geometrical relationship of the sensor coordinate and target coordinate. The depth and orientation of the target surface are directly determined by the ellipse parameters. In particular, two discontinuous points on the ellipse pattern, induced by seam trajectory, indicate mathematically the 3D direction for robotic tracking. To investigate the performance of this method, experiments with a 6 axis robot system are conducted on two different types of seam trajectories. The results show that this method is very suitable for robot seam tracking applications due to its excellence in accuracy and efficiency.

• Journal of the Korean Ceramic Society
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• 제53권6호
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• pp.700-706
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• 2016

Etch rate, surface roughness and microstructure as plasma resistance were evaluated for six kinds of oxide glass with different compositions. Borosilicate glass (BS) was found to be etched at the highest etch rate and zinc aluminum phosphate glass (ZAP) showed a relatively lower etch rate than borosilicate. On the other hand, the etching rate of calcium aluminosilicate glass (CAS) was measured to be similar to that of sintered alumina while yttrium aluminosilicate glass (YAS) showed the lowest etch rate. Such different etch rates by mixture plasma as a function of glass compositions was dependent on whether or not fluoride compounds were formed on glass and sublimated in high vacuum. Especially, in view that $CaF_2$ and $YF_3$ with high sublimation points were formed on the surface of CAS and YAS glasses, both CAS and YAS glasses were considered to be a good candidate for protective coating materials on the damaged polycrystalline ceramics parts in semi-conductor and display processes.

• Proceedings of the KSMRM Conference
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• 대한자기공명의과학회 2002년도 제7차 학술대회 초록집
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• pp.106-106
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• 2002

Purpose： The purposes of our study are (1) to develop a brain phantom which can be used for multimodal image registration, (2) to evaluate the accuracy of image registration with the home-made phantom. Method： A brain phantom which could be used for image registration technique of CT-MR and CT-SPECT images using chamfer matching was developed. The brain phantom was specially designed to obtain imaging dataset of CT, MR, and SPECT. The phantom had an external frame with 4 N-shaped pipes filled with acryl rods for CT, MR imaging and Pb rods for SPECT imaging. 8 acrylic pipes were inserted into the empty space of the brain phantom to be imaged for geometric evaluation of the matching. Accuracy of image fusion was assessed by the comparison between the center points of the section of N-shaped bars in the external frame and the inserted pipes of the phantom. Technique with partially transparent, mixed images using color on gray was used for visual assessment of the image registration process.

• Journal of the Korean Society of Safety
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• 제22권1호
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• pp.7-12
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• 2007

There are two kinds of design process for sprinkler system. one is pipe schedule system and the other is hydraulically designed system. We have inefficient results when we design by hydraulically designed system because the design process for sprinkler system is restricted by domestic fire code. Therefore, it is essential to do an introduction of hydraulically designed system which is based on engineering for enhancing reliability and efficiency of sprinkler system. This study presents points at issue by comparing and studying design standards of sprinkler system from Korea, Japan and NFPA, and presents improvement plans of national fire safety code of sprinkler system by processing, comparing and analyzing designs according to piping schedule and hydraulically designed system about domestic objects. Installation standards of sprinkler system have to be applied not by object buildings but by hazard classification. It is hard to design an efficient sprinkler system for fire control when water supply requirement of sprinkler systems allocated according to a size of a building because the same purpose but other buildings may request more water requirement or less. We should sublate the pipe schedule system from national fire safety code and need to introduce the hydraulically designed system. The pipe schedule system presents easy access because it is based on the forecasted engineering calculations but it is applied to only small buildings like NFPA due to its low reliability.

• Nuclear Engineering and Technology
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• 제53권2호
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• pp.647-656
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• 2021

Knowing a material's true stress-strain curve is essential for performing a nonlinear finite element analysis to solve an elastoplastic problem. This study presents a simple methodology to determine the true stress-strain curve of type 304 and 316 austenitic stainless steels in the full range of strain from a typical tensile test. Before necking, the true stress and strain values are directly converted from engineering stress and strain data, respectively. After necking, a true stress-strain equation is determined by iteratively conducting finite element analysis using three pieces of information at the necking and the fracture points. The Hockett-Sherby equation is proposed as an optimal stress-strain model in a non-uniform deformation region. The application to the stainless steel under different temperatures and loading conditions verifies that the strain hardening behavior of the material is adequately described by the determined equation, and the estimated engineering stress-strain curves are in good agreement with those of experiments. The presented method is intrinsically simple to use and reduces iterations because it does not require much experimental effort and adopts the approach of determining the stress-strain equation instead of correcting the individual stress at each strain point.

• Annals of Hepato-Biliary-Pancreatic Surgery
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• 제26권3호
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• pp.229-234
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• 2022

When planning pancreaticoduodenectomy for pancreatic head cancer, the prevalence of anatomical variation of the proximal jejunal vein (PJV), the associated short-term surgical outcomes, and the level of PJV convergence to the superior mesenteric vein must be carefully analyzed from both technical and oncological points of view. The prevalence of the first jejunal trunk (FJT) and PJV located ventral to the superior mesenteric artery is 58%-88% and 13%-37%, respectively. Patients with the FJT had a larger amount of intraoperative bleeding and a higher proportion of patients requiring transfusions compared to those without a common trunk. The risk of transfusion was higher in patients with ventral PJV compared to those with dorsal PJV. Although less frequent, sacrificing the FJT can result in fatal venous congestion of the jejunum. Therefore, a well-planned approach for pancreaticoduodenectomy, based on preoperative evaluation of anatomical variation in the PJV, may help reduce intraoperative bleeding and postoperative morbidity. Additionally, the importance of invasion into the PJVs should be revisited in terms of resectability and oncological clearance.

• The Journal of Korean Academy of Prosthodontics
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• 제43권2호
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• pp.191-203
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• 2005

Statement of problem. In Korea, the preliminary impression trays for dental and edentulous maxillae are manufactured on the base of the statistical value of Westerners. There had been less study on the dental and edentulous arches of Koreans. Purpose. The purpose of this study was to evaluate an average dental cast, preliminary impression trays, three-dimensional relation of dental and edentulous maxilla of Koreans Material and methods. The subjects for this study were 173 dental casts of maxilla (dental: 52, edentulous : 146) with ages $18\{\sim}60$ years old. Each of the master casts was measured 69 measuring points on the dental cast or maxilla, and 46 measuring points on the edentulous cast of maxilla with three-dimensional digital measuring machine. Each measuring points were analysed and were overlapped, that three dimensional dental graphic manufactured by CAD/CAM system. Results. 1. A standard of distribution to alveolar bone were width between left and right buccal border lines of the standard 3/4 line. The mean value of dental and edentulous casts were 67.27mm, 63.49mm respectively. 2. Morphological classification of dental casts were divided into three groups or V-shape, O-shape, U-shape, that proportion of distribution were 17%, 16%, 67%, respectively. Dimensional classification of the dental casts were divided into five groups of less than 63mm, 63 up to 65mm, 65 up to 67mm. 67 up to 69mm, more than 69mm, respectively. 3. Morphological classification of edentulous casts were divided into three groups or V-shape, O-shape, U-shape, that proportion of distribution were 18%, 17%, 65%, respectively Dimensional classification of the edentulous casts were divided into five groups of less than 57mm, 57 up to 61mm, 61 up to 65mm, 65 up to 69mm, more than 69mm, respectively. 4. Mean dental and edentulous cast of maxilla were overlapped, the proportion of bone resorption to alveolar bone is higher than that of palatal bone, its difference were higher anterior 2/4 area than posterior 3/4 area. Conclusion. It obtains information of preliminary impression trays for dental and edentulous maxilla of Koreans.

• Journal of the Korean Institute of Oriental Medical Informatics
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• 제17권2호
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• pp.82-129
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• 2011

"Beijijiufa" is a medical book republished by Sun Ju Qing in 1245. He compiled this book having added "Qizhumajiufa" and "Zhugejingyanbeijiyaofang" to the contents of "Beijijiufa" authored by Wen Ren Qi Nian. In "Beijijiufa" the author described treatment methods making use of moxibustion methods in connection with 22 cases of acute diseases. The author had collected the moxibustion methods used to treat acute diseases, which had been practiced by the medical practitioners of many generations, and quoted total 13 medical men's practices. In the book, the greatest parts of details were quoted especially from the writings of Sun Si Miao and Ge Hong, and this shows that the medical philosophies of both Sun Si Miao and Ge Hong were reflected onto "Beijijiufa". He had differed on his moxibustion practice: the size of moxa wool, the number of moxibustion treatment, and method of moxibustion for male and female were differed from one another according to the disease. As to the area of moxibustion, he chose the body parts around under four limbs and joints, and mostly used extraordinary acupoints rather than twelve main meridians. In his descriptions of finding meridian points, he did not describe it by its specific name of the reaction point, but explained the location of moxibustion points in detail through pictures. "Qizhumajiufa" is related to moxibustion method and prescriptions to treat surgical diseases, like skin boils or furuncle on the back, etc. He easily explained the method to find the meridian points for moxibustion treatment by using particular way through diagrams and pictures. Eight prescriptions he used were the collections among the historical practices of medical practitioners of many generations for skin boils which showed excellent therapeutic actions. In "Zhugejingyanbeijiyaofang", there are prescribed for 36 disease, also is the records of treatment methods for medical emergency which would be encountered easily in everyday life. As to therapeutic remedies, varied treatment methods, including the treatment by means of pasting and attaching medicinal substance to the spot, the treatment by means of mixing medicinal substance with alcoholic beverage, cleansing method, smoke inhalation remedy etc. were introduced. In "Beijijiufa" moxibustion was regarded as a top priority for treatment of acute disease, and the author strived to present remedies to the readers as easily as possible through 19 pictures. Regarding prescriptions, the author introduced diverse treatment methods with respect to various disease symptoms, and described the method to treat disease symptoms making use of medicinal ingredients which can easily be found in daily life. Likewise, "Beijijiufa" compiled by Sun Ju Qing was intended for clinical practice, and was indeed a medical book having been utilized for treatment of acute diseases in those days.

• Journal of Environmental Health Sciences
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• 제50권2호
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• pp.157-167
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• 2024

Background: Several previous studies have shown that commuting is a source of stress for undergraduate students. However, few studies have investigated the effect of commuting on academic stress among undergraduate students, and there has been little awareness of the environmental impact of commuting. Objectives: To evaluate the associations between commute type and/or time and academic stress among undergraduate students in South Korea, focusing on environmental sustainability. Methods: We conducted an online survey and obtained information on commute types, commute times, and academic stress from 510 undergraduate students aged ≥19 years. Academic stress was comprised of five sub-categories of stress, and total academic stress ranged from 5 to 25 points. Multiple linear regression analysis was used to analyze the associations between commute type and commute time and academic stress. Furthermore, the students were grouped into 21 categories based on their transportation mode for commuting. CO₂ emission factors per each commuting category were calculated using the transportation type's CO₂ emission data from previous studies. Spearman's correlation analysis was used to confirm the correlation between CO₂ emission factors and total academic stress. Results: Students using home-to-school transportation without transfers (vs. walking) showed a significantly higher total academic stress of 2.19 points (95% CI: 0.58, 3.80). In contrast, students using school-to-home transportation without transfers (vs. walking) showed a significantly lower total academic stress of 1.96 points (95% CI: -3.55, -0.38). Moreover, students using transportation with lower CO₂ emission factors had lower academic stress scores (home-to-school: correlation coefficient = 0.507, p<0.001; school-to-home: correlation coefficient = 0.491, p<0.001). Conclusions: Our findings suggest that both commute type and time are significantly associated with academic stress among South Korean undergraduate students. When students select environmentally-friendly transportation, they may not only improve their mental health but also improve climate resilience.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제21권11호
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• pp.420-426
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• 2020

The purpose and main points of the ROK-US Navy were analyzed from various angles using the big data technology Word Cloud for efficient sea trials. First, a comparison of words extracted through keyword cleansing in the ROK-US Navy sea trial showed that the ROK Navy conducted a single equipment test, and the US Navy conducted an integrated test run focusing on the system. Second, an analysis of the ROK-US Navy sea trials showed that approximately 66.6% were analyzed as similar items, of which more than two items were 112 items Approximately 44% of the 252 items of the ROK Navy sea trials overlapped, and that 89 items (35% of the total) could be reduced when integrated into the US Navy sea trials. A ship is a complex system in which multiple equipment operates simultaneously. The focus on checking the functions and performance of individual equipment, such as the ROK Navy's sea trials, will increase the sea trial period because of the excessive number of sea trial targets. In addition, the budget required will inevitably increase due to an increase in schedule and evaluation costs. In the future, further research will be needed to achieve more efficient and accurate sea trials through integrated system evaluations, such as the U.S. Navy sea trials.