• KIPS Transactions on Computer and Communication Systems
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• v.11 no.11
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• pp.411-418
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• 2022

Incorrectly loaded containers can easily knock down by strong winds. Container collapse accidents can lead to material damage and paralysis of the port system. In this paper, We propose a deep learning-based container loading state and accident risk detection technique. Using Darknet-based YOLO, the container load status identifies in real-time through corner casting on the top and bottom of the container, and the risk of accidents notifies the manager. We present criteria for classifying container alignment states and select efficient learning algorithms based on inference speed, classification accuracy, detection accuracy, and FPS in real embedded devices in the same environment. The study found that YOLOv4 had a weaker inference speed and performance of FPS than YOLOv3, but showed strong performance in classification accuracy and detection accuracy.

• The Journal of Advanced Prosthodontics
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• v.15 no.2
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• pp.55-62
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• 2023

PURPOSE. The aim of this study is to evaluate the accuracy of removable partial denture (RPD) frameworks produced using different digital protocols. MATERIALS AND METHODS. 80 frameworks for RPDs were produced using CAD-CAM technology and divided into four groups of twenty (n = 20): Group 1, Titanium frameworks manufactured by digital metal laser sintering (DMLS); Group 2, Co-Cr frameworks manufactured by DMLS; Group 3, Polyamide PA12 castable resin manufactured by multi-jet fusion (MJF); and Group 4, Metal (Co-Cr) casting by using lost-wax technique. After the digital acquisition, eight specific areas were selected in order to measure the Δ-error value at the intaglio surface of RPD. The minimum value required for point sampling density (0.4 mm) was derived from the sensitivity analysis. The obtained Δ-error mean value was used for comparisons: 1. between different manufacturing processes; 2. between different manufacturing techniques in the same area of interest (AOI); and 3. between different AOI of the same group. RESULTS. The Δ-error mean value of each group ranged between -0.002 (Ti) and 0.041 (Co-Cr) mm. The Pearson's Chi-squared test revealed significant differences considering all groups paired two by two, except for group 3 and 4. The multiple comparison test documented a significant difference for each AOI among group 1, 3, and 4. The multiple comparison test showed significant differences among almost all different AOIs of each group. CONCLUSION. All Δ-mean error values of all digital protocols for manufacturing RPD frameworks optimally fit within the clinical tolerance limit of trueness and precision.

• Nuclear Engineering and Technology
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• v.56 no.1
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• pp.132-140
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• 2024

In the event of a severe accident in Sodium Cooled Fast Reactors (SFR), the sodium combustion aerosols along with fission product aerosols would migrate to the environment through leak paths of the Reactor Containment Building (RCB) concrete wall under positive pressure. Understanding the characteristics of sodium aerosol transport through concrete leak paths is important as it governs the environmental source term. In this context, experiments are conducted to study the influence of various parameters like pressure, initial mass concentration, leak path diameter, humidity etc., on the transport and deposition of sodium aerosols in straight leak paths of concrete. The leak paths in concrete specimens are prepared by casting and the diameter of the leak path is measured using thermography technique. Aerosol transport experiments are conducted to measure the transported and plugged aerosol mass in the leak paths and corresponding plugging times. The values of differential pressure, aerosol concentration and relative humidity taken for the study are in the ranges 10-15 kPa, 0.65-3.04 g/m³ and 30-90% respectively. These observations are numerically simulated using 1-Dimensional transport equation. The simulated values are compared with the experimental results and reasonable agreement among them is observed. From the safety assessment view of reactor, the approach presented here is conservative as it is with straight leak paths.

• Journal of the Korean Society of Costume
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• v.22
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• pp.263-276
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• 1994

The achievement of notable social reoforms attained during the period of 19th and 20th centuries needlessly speaking remodelded the social environmental into several different patterns such as :1) high industrialization 2) propensity to consume 3) up graded overall social stands. Accordingly the industrial world of the but-tons too established the mess production syhstem by breaking from convention of hand-craft work of 17th century. The raw materials used in the production line on buttons during the 20th century are almost all-kind of materials one can possibly named including cheap plastic which enabled production lines to produce cheaper but higher productivities of the buttons being produced, The design (incused design) used in the 19-20h centuries are : men landscape, sports features, birds, livestocks, bugs, or geomatric features, tec, 1, The classification o f the buttons by materials Techniques shapes colors marking (Incused design) used in the productionof buttons in the England United States of America Laska Italy france Denmark Japan and India are categolizzed as : natural raw materials and syntetical resines. 1) Of the natural raw materials used are : Matal Enamel Iodine Agate, Coral, Green jade(Jasper) Granite, Wood, Ivory, Horn and bone etc. 2) The sythetical resin used in the button in-dustries are : Artificial jewell glass Acrylic material Styroform Celluloid and Nylon etc. 2. The thecnique quoted in producing buttons are hand craft work inlay work precision casting press mosic dye etching, processing, engraving and embossed carving etc. 3. The major designs used in the buttons in -dustries are : Round shape however elliptical column angular and edge shape often used. 4. The colors used are : The multi-colors were highly used than mono-colored materials such as : Adjoining Color and Contrast Color. The highest consideration to be considered in choosing the colors for the buttons are harmonization and matching factor with the garment or dresses to be wore. 5. The major design(incused design) on the buttons are embodiment and the design were also used in order of abstractive-combination abstractive with has offers much surprising. The button industries during the 19th and 20th centuries were not only the determination factors those can judge the value of self-pride of Nation and which were far beyond the in-dustrial arts in those days but also highly refelected and influenced by cultural sense ideology and self-pride of the Nation of those period. The followings are details of the role of the buttons categolized in the order of functional ornamental and symbolical aspects : 1. The functional role : The functional role of the buttons were simply designed for dress how-ever the buttons beyond from this role of function now a days. 2. The ornamental role : The ornamental role of he button beyond from this role of the button were effectuated by : 1) shape materials colors 2) technique locations size and design (incused design) 3) The ramaterials used for buttons shall not be over looked because it is highly depends on the taste sense and combination of harmony with the garment to be wore. 4) The color of the buttons are made well contrasted with the color of garments just as in the case of other artistical area such as matchs with the color of garment of contrast with brigtness of colors contrasted as complementary color and so and so. 5) The technique being adoped are: precision casting press handcraft inlay work etching mosic etc,. Since the buttons are no longer a simple catching devise used to fasten together the different part of the dress but now it has formed own and occupied the independent role in the garment or dresses location can be de-termined and varying depending on the ideas of designers. The size of the buttons has no specific limits, However the variation has widely dependined on the entire circumperence rhythm contrast harmonization of the garments. 3. The symbolical role : Since the button is no longer a just a simple devise for catching and fastening device used fastening together the different part of the garments but now were built a independent area as major part of the Garment and well reflected all kinds of occupations political background cultural as-pect etc. on the buttons. The design of buttons in the western circles are more simplified but they are polished looks and their techniques of manufacturing are comination of both machanis and handcraft. The colors used in the buttons are pretty well harmonized with garment(dress). Almost all kind of materials can be used in the but-tons however materials used in the buttons are : Bone of livestocks ivory, turtle shell are no longer used because the prevention of cruely of animal. On the contraly the level of buttons indus-try of Korea is far to reach and catch up with the level of western circles. It is highly suggested therefore the but-tons industrial field of Republic of Korea shall place and encouragement in producing beter industrial environment of the buttons based on the traditional and cultural aspect of republic of Korea to produce both manufacturing of qulified and best designed and colored buttons.

• The Journal of Advanced Prosthodontics
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• v.9 no.3
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• pp.176-181
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• 2017

PURPOSE. The purpose of this study was to evaluate the marginal and internal gaps of Ni-Cr and Co-Cr copings, fabricated using the dental ${\mu}-SLA$ system. MATERIALS AND METHODS. Ten study dies were made using a two-step silicone impression with a dental stone (type IV) from the master die of a tooth. Ni-Cr (NC group) and Co-Cr (CC group) alloy copings were designed using a dental scanner, CAD software, resin coping, and casting process. In addition, 10 Ni-Cr alloy copings were manufactured using the lost-wax technique (LW group). The marginal and internal gaps in the 3 groups were measured using a digital microscope ($160{\times}$) with the silicone replica technique, and the obtained data were analyzed using the non-parametric Kruskal-Wallis H test. Post-hoc comparisons were performed using Bonferroni-corrected Mann-Whitney U tests (${\alpha}=.05$). RESULTS. The mean (${\pm}$ standard deviation) values of the marginal, chamfer, axial wall, and occlusal gaps in the 3 groups were as follows: $81.5{\pm}73.8$, $98.1{\pm}76.1$, $87.1{\pm}44.8$, and $146.8{\pm}78.7{\mu}m$ in the LW group; $76.8{\pm}48.0$, $141.7{\pm}57.1$, $80.7{\pm}47.5$, and $194.69{\pm}63.8{\mu}m$ in the NC group; and $124.2{\pm}52.0$, $199.5{\pm}71.0$, $67.1{\pm}37.6$, and $244.5{\pm}58.9{\mu}m$ in the CC group. CONCLUSION. The marginal gap in the LW and NC groups were clinically acceptable. Further improvement is needed for CC group to be used clinical practice.

• Journal of Conservation Science
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• v.26 no.3
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• pp.269-276
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• 2010

This study aims to extract manufacturing techniques by analysing metallurgical characteristics of the cast-iron pot from Bubjusa, examining corrosion status and microstructure with a optical microscope, SEM-EDS, micro vickers hardness tester and XRD. The microstructure analysis has presented that ferrite and partial portion of pearlite exist within the corroded outer layer. The analysis of the inner layer revealed that there is pearlite and graphite of feather shape. The one of the middle layer, which is placed between outer and inner layer, showed that corrosion has been heavily developed. Micro vickers hardness values range from 217Hv to 698Hv in constituent layers and such values lie within the ranges of the ancient iron relics. The result of EDS analysis for each microstructure presented that the outer layer has been more decarbonized than the inner layer. XRD analysis of iron corrosion compound revealed that Goethite and Hematite had been produced from the corrosive process of iron. The study concludes that the large iron pot was made by casting technique, and microstructure of inner layer had a gray cast iron. Outer layer has been decarbonized through repetitive process of heating and cooling. This results can be used as fundamental data for comparative study to reveal manufacturing techniques of large cast-iron pot.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.5
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• pp.545-566
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• 1999

The use of pure titanium and titanium alloys have been increased recently in fixed, removable prosthodontics and implant fields as a framework. But when they were used for superstructures of implant or metal framework of removable prosthesis, welding is necessary to reconnect the fracture site to control the casting distortions. To overcome the difficulties in soldering the titanium due to high oxidation property, much effort have been devoted. In this study, some of mechanical properties were compared between pure titanium and Ti-6Al-4V alloy by using after welding, electron beam welding technique and tungsten arc welding. Mechanical properties such as tensile strength, yield strength, elongation and microhardness were measured. And, in order to compare the effect of welding site and surrounding metal tissue according to the welding condition, SEM photographs were taken and element distribution was observed by Wave Dispersion Spectroscopy. Through analyses of the data, following results were obtained; 1. In items such as tensile strength, yield strength and elongation according to the welding techniques of pure titanium, only tungsten arc welded group showed significant lower value than other groups(P<0.05). 2. In items such as tensile strength and yield strength according to the welding techniques of Ti-6Al-4V alloy, control group and tungsten arc welded group showed significant difference among all the groups(P<0.05). 3. Ti-6Al-4V alloy exhibited significantly greater elongation than control group when the laser welding method and electron beam welding method were used, and elongation showed increasing tendency. 4. Pure titanium specimens exhibited increasing tendency of microhardness regardless of the weld-ing technique applied, and especially tungsten arc welded group demonstrated a great increase of microhardness than parent metal. 5. There was no hardness change in laser welded group and electron beam welded group of Ti-6Al-4V alloy, but in tungsten arc welded group, hardness changed greatly from parent metal to weld seam. 6. Through the metallographic examination and scanning electron microscopy, laser welding caused central fusion and recristallizations were formed and tungsten arc welding caused localized fusion to 0.3-0.7mm from the surface.

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.2
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• pp.173-178
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• 2018

The direct metal laser sintering (DMLS) technique would be promising for the full-arch implant-supported restorations due to reduced cost and manufacturing time without potential human errors and casting defects. The aims of this case report were to describe the successful outcome of an implant-supported fixed dental prosthesis in the edentulous maxilla by using the DMLS technology and computer-aided design and computer-aided manufacturing (CAD/CAM) monolithic zirconia crowns, and to describe its clinical implications. A healthy 51-year-old Korean woman visited Seoul National University Dental Hospital and she was in need of a rehabilitation of her entire maxilla due to severe tooth mobility. In this case, all maxillary teeth were extracted and an implant-supported fixed dental prosthesis was fabricated that involved a cobalt-chromium (Co-Cr) framework with the DMLS technique and CAD/CAM monolithic zirconia crowns. Six months after delivery, no distinct mechanical and biological complications were detected and the prosthesis exhibited satisfactory esthetics and function. In this case report, with the DMLS system, the three-dimensional printed prosthesis was created without additional manual tooling and thus, reliable accuracy and passive fit were obtained.

• Journal of Korea Game Society
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• v.7 no.4
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• pp.71-80
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• 2007

In this paper, we introduce an efficient GPU-based real-time rendering technique applicable to every kind of game. Our method, without an extra geometry, can represent terrain just with a height map. It makes it possible to freely go around in the air or on the surface, so we can directly apply it to any computer games as well as a virtual reality. Since our method is not based on any geometrical structure, it doesn't need special LOD policy and the precision of geometrical representation and visual quality absolutely depend on the resolution of height map and color map. Moreover, GPU-only technique allows the general CPU to be dedicated to more general work, and as a result, enhances the overall performance of the computer. To date, there have been many researches related to the terrain representation, but most of them rely on CPU or confmed its applications to flight simulation, Improving existing displacement mapping techniques and applying it to our terrain rendering, we completely ruled out the problems, such as cracking, poping etc, which cause in polygon-based techniques, The most important contributions are to efficiently deal with arbitrary LOS(Line Of Sight) and dramatically improve visual quality during walk-through by reconstructing a height field with curved patches. We suggest a simple and useful method for calculating ray-patch intersections. We implemented all these on GPU 100%, and got tens to hundreds of framerates with height maps a variety of resolutions$(256{\times}256\;to\;4096{\times}4096)$.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.3
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• pp.288-295
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• 2019

Passive fit of prosthesis is an essential property of implant supported prosthesis for long term success and minimization of complications. And the property is determined mostly by fabrication procedure. There were limitations of extensive implant prosthesis because conventional casting method generate contraction error of long span prosthesis. However, Computer-aided design/Computer-aided manufacturing (CAD/CAM) technology of 3D printing and milling metal framework can overcome those limitations. This case is a full mouth rehabilitation using extensive implant fixed prosthesis. Removable interim prosthesis was made for esthetic, functional evaluation and a guide for implant insertion. After the insertion, implant fixed interim prosthesis was delivered. After additional evaluation and adjustment, final prosthesis was designed with CAD, the fabricated with CAM. Milling technique was used for anterior screw type implant superstructure and 3D printing technique was used for the anterior and posterior implant copings. Fit of the final restoration was favorable. The practitioner and patient were both esthetically and functionally satisfied with the final result.