• The Journal of Advanced Prosthodontics
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• v.6 no.1
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• pp.22-29
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• 2014

PURPOSE. This study aimed to investigate the potential clinical application of digitized silicone rubber impressions by comparing the accuracy of zirconia 3-unit fixed partial dentures (FPDs) fabricated from 2 types of data (working model and impression) obtained from a laser scanner. MATERIALS AND METHODS. Ten working models and impressions were prepared with epoxy resin and vinyl polysiloxane, respectively. Based on the data obtained from the laser scanner (D-700; 3Shape A/S, Copenhagen, Denmark), a total of 20 zirconia frameworks were prepared using a dental CAD/CAM system (DentalDesigner; 3shape A/S, Copenhagen, Denmark / Ener-mill, Dentaim, Seoul, Korea). The silicone replicas were sectioned into four pieces to evaluate the framework fit. The replicas were imaged using a digital microscope, and the fit of the reference points (P1, P2, P3, P4, P5, P6, and P7) were measured using the program in the device. Measured discrepancies were divided into 5 categories of gaps (MG, CG, AWG, AOTG, OG). Data were analyzed with Student's t-test ($\alpha$=0.05), repeated measures ANOVA and two-way ANOVA (${\alpha}=0.05$). RESULTS. The mean gap of the zirconia framework prepared from the working models presented a narrower discrepancy than the frameworks fabricated from the impression bodies. The mean of the total gap in premolars (P=.003) and molars (P=.002) exhibited a statistical difference between two groups. CONCLUSION. The mean gap dimensions of each category showed statistically significant difference. Nonetheless, the digitized impression bodies obtained with a laser scanner were applicable to clinical settings, considering the clinically acceptable marginal fit ($120{\mu}m$).

• Journal of electromagnetic engineering and science
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• v.1 no.1
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• pp.18-23
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• 2001

A fast-sweep broadband FM reflectometer system has been successfully developed and operacted at the DIII-D tokamak, producing reliable density Profiles with excellent spatial (1 $\leq$ cm) and temporal resolution (~100 $\mu$ s). The system uses a solid-state microwave oscillator and an active quadrupler, covering full Q-band frequencies (33~50 GHz) and providing relatively high output power (20~60 mW). The system hardware allows fu11band frequency sweep in 10 $\mu$ s, but due to digitization rate limit on DIII-D, sweep time was limited to 75~100 $\mu$ s. Fast frequency sweep has helped to reduce density fluctuation effects on the reflectometer phase measurements, thus improving reliability for individual sweeps. The fast-sweep system with high spatial and temporal resolution has allowed to measure fast-changing edge density profiles during plasma ELMS and L-H transitions, thus enabling fast-time sca1e physics studies.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.45 no.3
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• pp.66-77
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• 2022

Digitization and automation technologies have rapidly maximized productivity and efficiency in all industries over the past few decades. Construction automation technology has either stagnated over the same period or has not kept pace with overall economic productivity. According to the research studies up to now, the output of concrete structures using coarse aggregates (8mm or more) is very limited due to the limitations of equipment and materials. In this study, information on the development process of 3DCP equipment that can print concrete structures with the printing width (100 mm or more) and printing thickness (30 mm or more) using a 3DCP material mixed with coarse aggregate (8 mm or more) is provided. To verify the performance of the developed 3DCP equipment, experimental data are provided on output variables, the number of layers, and the inter-layer printing time interval. The evaluation and verification data of various mechanical properties (compressive and splitting tensile strength) of printed materials using coarse aggregates are provided.

• Tunnel and Underground Space
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• v.28 no.5
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• pp.387-399
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• 2018

Mine reclamation project is closely related to human's past mining activities and the current human's living environment. It is a reason for the national management. In order to efficiently carry out mine reclamation projects, a precise investigation and analysis of the underground space of the abandoned mine is required. Korea MINE RECLAMATION Corp. is developing a practical technology that is effective in investigating and actually measuring underground cavities. MIRECO EYE system is an exploration equipment for 3D digitization and figuration of underground cavities. As combining a laser, sonar and image acquisition technology, it enables access to information about inaccessible underground cavities and effective management of subsidence risk of mined area. and currently it is also utilized for various purposes in related areas such as investigating urban sinkholes. This article is precise numerical and geometric information analysis obtained through MIRECO EYE system.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.5
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• pp.230-238
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• 2023

Small and medium-sized food manufacturing enterprises are largely reliant on manual labor, from inputting raw materials to palletizing the final product. Recently, there has been a trend toward smartness and digitization through the implementation of robotics and sensor data technology. In this study, we examined the effectiveness of improvement through 3D simulation on two repetitive work processes within a food manufacturing company. These processes involve workers whose speed cannot match the capacity of the applied equipment. Two manual processes were selected: the weighing and packing process performed by workers after skewer assembly, and the manual batch process of counting randomly delivered frozen foods, packing (both internal and external), and palletizing. The production volume, utilization rate, and number of workers were chosen as verification indicators. As a result of the simulation for improving the 3D process, production increased by 13.5% and 56.8% compared to the existing process, respectively. This was particularly evident in the process of applying palletizing robots. In both processes, as the utilization rate and number of input workers decreased, robots could replace tasks with high worker fatigue, thereby reducing work overload. This study demonstrates the potential to visually compare the process flow improvement using 3D simulations and confirms the possibility of pre-validation for improvement.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.3
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• pp.274-282
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• 1998

This study deals with sinking resistance for purse seine, in the case of different d/l, ratio of twine diameter and leg length. Experiments carried out on the six types simplified reduced model seines which were made of knotless netting. The nettings were woven in different leg length 4.3, 5.0, 5.5, 6.0, 6.6 and 7.7mm of polyester 28 tex two threads two -ply twine, and each of the seines were named I, II, III, IV, V and Ⅵ seine. Dimension of seine models were 450cm for corkline and 85cm for seine depth, each seines rigged up 160g of float for a floatline and 50g (underwater weight) of lead for a leadline. Experiments were measured in the observation channel of a flume tank at the static conditions Sinking motion was recorded by the two sets TV-camera for VTR which were placed in top and side of the model seine, and reading coordinate carried out by the video digitization system. An analysis were calculated out by simultaneous differential equations for numerical method by Runge - Kutta - Gill sub - routine. The results obtained were as follows: 1. Average sinking speed of seine of seine margin was fastest for Ⅵ seine followed by V, IV, III, II and I seines. 2. The coefficient of resistance for a seine wall was depended upon the ratio of d/l : KD =0.081 (d/l )-0.5 3. The coefficient of resistance for netting bundle was not depended upon the ratio of d/l :CR = 0.91 (), d : Twine diameter, l : Leg length, : Density of netting materals, $\omega$ : Density of water

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.11C
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• pp.1053-1059
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• 2005

The computer generated hologram (CGH) designs and produces digital information for generating 3-D (3-Dimension) image using computer and software instead of optically-sensed hologram of light interference, and it can synthesis a virtual object which is physically not in existence. Since digital hologram includes an amount of data as can be seen at the process of digitization, it is necessary that the data representing digital hologram is reduced for storing, transmission, and processing. As the efforts that are to handle hologram with a type of digital information have been increased, various methods to compress digital hologram called by fringe pattern are groped. Suitable proposal is encoding of hologram. In this paper, we analyzed the properties of CGH using tools of frequency transform, assuming that a generated CGH is a 2D image by introducing DWT that is known as the better tool than DCT for frequency transform. The compression and reconstruction result which was extracted from the wavelet-based codecs illustrates that it has better properties for reconstruction at the maximum 2 times higher compression rate than the Previous researches of Yoshikawa[2] and Thomas[3].

• Journal of KIBIM
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• v.11 no.4
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• pp.20-30
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• 2021

In the era of the 4th industrial revolution, smart construction is actively researched, in the domestic construction field, and one of the key elements in this field is Building Information Modeling(BIM). In Korea, smart construction is being implemented through BIM-based digitization and intelligence. The geotechnical engineering field should also prepare for the introduction of BIM. In this study, the concept and application status of GeoBIM were identified, and the direction of future research was presented. This study is a part of the study "Establishment of GeoBIM-based Digital Twin Maintenance System" in the current "Technology Development for Establishment of Jeju Ground Collapse Response System for Safe Road Operation". The subject and scope of the study is continuous excavation at caves located under roads in Jeju Island, and initial research is being conducted on Jaeamcheon-gul and Jeonggusu-gul. This study aims to build a digital twin through individual data construction and integration processes such as cave shape modeling using laser scanners, 3D stratum modeling using borehole information and geophysical exploration data, and modeling of surrounding conditions using drones.

• International Journal of Computer Science & Network Security
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• v.21 no.12spc
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• pp.611-619
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• 2021

This article is devoted to the study of digital finance development in the global economy. The study aims to show the digital finance development level in different states and its impact on their economic development. In the course of the study, three hypotheses are put forward: 1) increased spending on innovation contributes to the competitiveness of financial services; 2) digital technology makes the financial systems of states more developed; 3) the development of digital finance contributes to the competitiveness at the level of states. Correlation and regression analysis are applied for building the empirical study. The results of the study helped to understand the digital finance concept. It also shows the main stages of digital finance development, the digitalization rank of the countries, the impact of digitalization on the financial and economic sphere. According to the results of empirical analysis, it is confirmed that the countries that invest more in innovative technologies are more developed. Therefore, digitalization has a significant value for the financial system and has a synergistic effect on all areas of the economy.

• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.4
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• pp.269-283
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• 2005

To figure out the cause of underestimating the roughness and shear strength of rock joints suggested by numerous researchers, we analyzed roughness mobilization characteristics, characteristics of roughness parameters, effects of sampling interval, and waviness for roughness parameters. It was found out that lack of understanding of the roughness mobilization characteristics, inappropriate applications of roughness parameters, and effect of aliasing provide a main reasons for those problems. Several practical alternatives for improving those problems were suggested. As far as digitizing methods are concerned, we can find that using a 3D scanner can give a relatively effective result. To avoid aliasing, sampling interval should be less than one-quarter of the minimum asperities. As for the quantification of roughness, it was analyzed that the roughness parameter should be classified into two components depending on the scale of roughness to apply the shear strength model. For classifying the roughness, a framework of the criterion was suggested based on the plastic flow concept for the asperity failure, and the basis for proposing a new alternative shear strength model was established.