• The Journal of Korean Academy of Prosthodontics
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• v.56 no.4
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• pp.375-383
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• 2018

Clinicians are faced with many difficulties when planning prosthodontic restorations with implants in a complete edentulous patient. When planning fixed implant prosthetics, it is often necessary to have additional surgery due to highly reduced alveolar bone, as well as high treatment costs and long-term treatment durations can be required. In addition, lack of interocclusal space can be a problem when planning implant supported overdentures. In this study, we planned to place a small number of implants on the anterior maxilla and used them as the abutments for distal-extension removable partial dentures on the posterior side in a maxillary fully edentulous patient. This would reduce the possibility of additional invasive operations such as alveolar bone graft, shorten the treatment time, and be relatively easy for elderly patients to burden. In this case, the patient was provided with a distal-extension removable partial denture and anterior implant fixed prostheses, which was similar to the previous one, and showed good adaptation, and chewing efficiency and esthetics was recovered.

• Journal of Korea Spatial Information System Society
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• v.11 no.2
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• pp.133-142
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• 2009

Recently, with the advance of wireless internet and the frequent use of mobile devices, demand for LBS(Location Based Service) is increasing, and research is required on spatial indexes for the storage and maintenance of spatial data to provide efficient LBS in mobile device environments. In addition, the use of flash memory as an auxiliary storage device is increasing in order to store large spatial data in a mobile terminal with small storage space. However, the application of existing spatial indexes to flash-memory lowers index performance due to the frequent updates of nodes. To solve this problem, research is being conducted on flash-memory based spatial indexes, but the efficiency of such spatial indexes is lowered by low utilization of buffer and flash-memory space. Accordingly, in order to solve problems in existing flash-memory based spatial indexes, this paper proposed FR-Tree (Flash-Memory based R-Tree) that uses the node compression technique and the delayed write operation technique. The node compression technique of FR-Tree increased the utilization of flash-memory space by compressing MBR(Minimum Bounding Rectangle) of spatial data using relative coordinates and MBR size. And, the delayed write operation technique reduced the number of write operations in flash memory by storing spatial data in the buffer temporarily and reflecting them in flash memory at once instead of reflecting the insert, update and delete of spatial data in flash-memory for each operation. Especially, the utilization of buffer space was enhanced by preventing the redundant storage of the same spatial data in the buffer. Finally, we perform ed various performance evaluations and proved the superiority of FR-Tree to the existing spatial indexes.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.681-686
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• 2011

SPLITT Fractionation (SF) provides separation of sample into two subpopulations. Separation into more than two subpopulations requires repeated SF operations. In this study, two Gravitation SF (GSF) channels were connected in a series (Tandem GSF) to obtain a separation into three subpopulations and to improve the fractionation efficiency (FE) of the fraction-b in the full-feed depletion (FFD) mode. In a single channel FFD-GSF operation, the fraction-a contained mostly the beads smaller than the cutoff diameter ($d_c$), while the fraction-b contained beads smaller than $d_c$ as well as those larger than dc, as expected. The measured FE's of the fraction-b are much lower than those of the fraction-a in all cases. The FE's of the fraction-a are higher than 84% with the average of about 91%, while those of the fraction-b are lower than 60% with the average of about 43%. No particular trends were found between FE and $d_c$, indicating the performance of FFD-GSF does not change with $d_c$ in the range where tested. Also no clear trends were observed between the FE and the sample-feeding flow rate, indicating higher sample-feeding rate can be used to increase the sample throughput without losing resolution. When two GSF channels were connected so that the flow stream emerging from the outlet-b of the channel-1 is fed directly into the channel-2, all three FE's measured for the fraction-1a were high with the average value of 99%, indicating it contains almost purely the beads smaller than $d_c$. The FE's measured for the fraction-2a are still good with the average value of 92%. The FE's measured for the fraction-2b are 64% in average, which is about 20% improvement from those obtained in a single channel FFD-GSF at the same conditions.

• Korean Journal of Environmental Agriculture
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• v.28 no.1
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• pp.69-74
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• 2009

In Korea, large amounts of chestnut shell as by-products are produced from food industries. However, most of the by-products exist with no disposal options. Biosorption uses biomass that are either abundant or wastes from industrial operations to remove toxic metals from water. Objective of this research was to evaluate the feasibility of using chestnut shell as by-products for removal of metal ions(Pb, Cu and Cd) from aqueous solution. The chestnut shell was tested for its efficiency for metal removal by adopting batch-type adsorption experiments. The adsorption selectivity of chestnut shell for metals was Pb > Cu > Cd at solution pH 5.5. The Langmuir isotherm adequately described the adsorption of chestnut shell for each metal. Using The maximum adsorption capacity predicted using Langmuir equation was 31.25 mg $g^{-1}$ 7.87 mg $g^{-1}$ and 6.85 mg $g^{-1}$ for Pb, Cu and Cd, respectively. Surface morphology, functional group and existence of metals on chestnut shell surface was confirmed by FT-IR, SEM and EDX analysis. The chestnut shell showed an outstanding removal capability for Pb compared to various adsorbents reported in the literatures. The overall results suggested that chestnut shell might can be used for biosorption of Pb from industrial wastewater.

• Knowledge Management Research
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• v.21 no.3
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• pp.1-25
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• 2020

This study analyzed key success factors of Korean car-sharing enterprises, Socar and Greencar, and the responsive strategies of Korean car-manufacturing company, Hyundai Motor Group, in the face of emerging sharing economy under the specific economic and regulatory system in Korea. The outcomes of the analysis are as follows. 'Timely market entry' in early startup phase and 'use of external resources' in early growth phase were key success factors common to both Socar and Greencar. However, the differences in the eventual business directions of the two companies also resulted in different key success factors in the expansion phase of their business. For Socar which focused on maintaining its independence and the external growth of B2C business, customer relation marketing and sufficient capital raising were key success factors. For Greencar which became a part of a business group and focused on improving the efficiency of business operations, timely market entry (B2B market) was key success factor. The use of external resources and cooperation with large corporations emerged as key success factors common to both companies in the rapid growth phase. The responsive strategies of the Hyundai Motor Group were collaboration, investment and direct management of DeliveryCar. The short-term goal of the responsive strategy was the operation of test-bed in collaboration with car-sharing company while the mid/long term goal was planning new mobility services by utilizing collected data. Securing opportunities for early market dominance for autonomous car industry was also found to be an important goal.

• Journal of Korea Water Resources Association
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• v.41 no.3
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• pp.293-303
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• 2008

Reservoir turbidity flows degrade the efficiency and sustainability of water supply system in many countries located in monsoon climate region. A decision support system called RTMMS aimed to assist reservoir operations was developed for the real time monitoring, modeling, and management of turbidity flows induced by flood runoffs in Daecheong reservoir. RTMMS consists of a real time data acquisition module that collects and stores field monitoring data, a data assimilation module that assists pre-processing of model input data, a two dimensional numerical model for the simulation of reservoir hydrodynamics and turbidity, and a post-processor that aids the analysis of simulation results and alternative management scenarios. RTMMS was calibrated using field data obtained during the flood season of 2004, and applied to real-time simulations of flood events occurred on July of 2006 for assessing its predictive capability. The system showed fairly satisfactory performance in reproducing the density flow regimes and fate of turbidity plumes in the reservoir with efficient computation time that is a vital requirement for a real time application. The configurations of RTMMS suggested in this study can be adopted in many reservoirs that have similar turbidity issues for better management of water supply utilities and downstream aquatic ecosystem.

• Korean Journal of Food Science and Technology
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• v.11 no.2
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• pp.86-92
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• 1979

Antioxidants. BHA, BHT and PG were added to a commercial soybean oil at a level of 200 ppm, and the antioxidant-treated oils and a control oil were subjected to 30 min. heating at $150{\pm}2^{\circ}C$ and 23.5 hr. cooling at room temperature for 6 times. Variations of % antioxidant retention and some physical and chemical properties of the oils were investigated. The results of the present study were as follows. 1. The % retention of BHA, BHT and PG after the second heating and cooling was respectively 60.5, 55.7 and 40.5 %. That of BHA, BHT and PG after the 6th heating and cooling was respectively 5.7, 3.0 and 1.8 %. 2. The refractive indices and viscosity of the oils, including the control, increased slowly at first. but after 4th heating and cooling, these values increased rapidly. The color indices of the oils, including the control, increased very rapidly, but after the 2nd heating and cooling, the rates of the increase diminished considerably. 3. The efficiency of each antioxidant in suppressing peroxide, thiobarbituric acid, and acid value development decreased rapidly as the antioxidant contents of the oils decreased. After the 6th heating and cooling, the peroxide. thiobarbituric acid and acid values of the oils treated initially with the antioxidants did not differ appreciably from those of the control.

• Journal of KIISE:Computing Practices and Letters
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• v.5 no.5
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• pp.543-552
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• 1999

The iterator technique which is used for implementing physical operators of the query executor is known for its efficiency and extensibility. The most widely used technique for processing an operator on spatial objects is to process by dividing it into the filter step and the refinement step. Recently, there was a research for an optimizer which can generate more efficient query execution plans than those of traditional methods by separating a spatial operator into filter and refinement steps in the level of the object algebra. But, traditional query executors were not designed considering such query execution plans. So they have no function of transmitting the result of the filter operation between operators. We propose two methods, the probe technique and the tag technique, which transmit the result of the filter operator when using the iterator in the query execution plan in which operators are separated by filter/refinement steps and other operators can be allowed between the steps. Whereas the probe technique extends the state record within an operator, the tag technique stores the result of a filter step in an intermediate result in the form of the tag. Based on the comparison of these methods, we design and implement a query executor using the tag technique that is superior in extensibility. The implemented query executor can execute operations defined in the Spatial Object Algebra(SOA) to process an extended OQL for spatial queries.

• Journal of Industrial Convergence
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• v.16 no.1
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• pp.21-26
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• 2018

The Seaborne Trade Volume accounts for 97% of the total. This means that the port operation management system can improve port efficiency, reducing operating costs, and the manager who manages all operations at the port needs to check and respond quickly when delays of work and equipment support is needed. Based on the real-time location information confirmation of yard automation equipment used the existing system GPS, the real-time location information confirmation system is a GPS system of the tablet, rather than a port operation system that monitors location information for the entered information, depending on the completion of the task or the start of the task. Network configurations also reduce container processing delays by using commercial LTE services that do not have shading due to containers in the yard also reduce container processing delays. Trough introduction of smart devices using Android or IOS and container processing scheduling utilizing artificial intelligence, we will build a minimum delay system with Smart Device usage of container processing applications and optimization of container processing schedule. The adoption of smart devices and the minimization of container processing delays utilizing artificial intelligence are expected to improve the quality of port services by confirming the processing containers in real time to consumers who are container information demanders.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.2
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• pp.314-323
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• 2022

Vessel Traffic Services (VTS) operators perform traffic management tasks using VTS systems and sensor equipment designated as VTS facilities to promote the safety and efficiency of vessel traffic. The necessary VTS information for effective operations could be obtained through the additional access of various information channels other than the designated VTS facility. To unify these various information access windows, the development of the VTS cloud system is in progress. In this study, the operational information analysis for VTS was performed through VTS tasks-facility linkage analysis to identify the user required information according to the introduction of the VTS cloud system. The VTS task analysis was performed through research of the international and domestic literature, and expert interviews. The necessary information were identified and linked according to the VTS facilities. As a result of the analysis, 37 categories of necessary information were identified for internal and external information windows, and 8 information windows were selected other than the present VTS equipment. The identified user requirements would be applied to the structure design of the VTS cloud system. In the future, it is necessary to update user requirements through scenario-based user operation analysis and to conduct additional research on the system interface design.