• Design & Manufacturing
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• v.14 no.1
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• pp.1-7
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• 2020

In this study, the variation of the shrinkage in the thickness direction of the molded parts according to the gate size of the polymer core fabricated through the 3D printer using the SLS method was studied. The polymer cores are laser sintered and the powder material is nylon base PA2200. The polymer cores have lower heat transfer rate and rigidity than the metal core due to the characteristics of the material. Therefore, the injection molding test conditions are set to minimize the deformation of the core during the injection process. The resin used in the injection molding test is a PP material. The packing condition was set to 80, 90 and 100% of the maximum injection pressure for each gate size. The runner diameter used was ∅3mm, and the gates were fabricated in semicircle shapes with cross sections 1, 2, and 3 ㎟, respectively. Thickness measurement was performed for 10 points at 2.5 mm intervals from the point 2.5 mm away from the gate, and the shrinkage to thickness was measured for each point. The shrinkage rate according to the gate size tends to decrease as the cross-sectional area decreases as the maximum injection pressure increases. The average thickness shrinkage rate was close to 0% when the packing pressure was 90% for the gate area of 1mm2. When the holding pressure was set to 100%, the shrinkage was found to decrease by 3% from the standard dimension due to the over-packing phenomenon. Therefore, the smaller the gate, the more closely the molded dimensions can be molded due to the high pressure generation. It was confirmed that precise packing process control is necessary because over-packing phenomenon may occur.

• Journal of radiological science and technology
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• v.40 no.3
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• pp.433-441
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• 2017

The 3D printing selective laser sintering (SLS) and stereo lithography apparatus (SLA) method used for bone model production has good precision and resolution, but the printers are expensive and need professional knowledge for operation. The program that converts computed tomography digital imaging and communications in medicine (DICOM) file into STL (stereolithography) file is also expensive so requesting 3D printing companies takes a lot of time and cost, which is why they are not generally utilized in surgery. To produce bone models of fractured patients, the use of 3D imaging conversion program and 3D printing system should be convenient, and the cost of device and operation should be low. Besides, they should be able to produce big size bone models for application to surgery. Therefore, by using an fused deposition modeling (FDM) method 3D printer that uses thermoplastic materials such as DICOM Viewer OsiriX and plastic wires, this study developed 3D printing system for Fracture surgery Patients customized bone model production for many clinics to use for surgery of fracture patients by universalizing with no limit in printing sizes and low maintenance and production cost. It is expected to be widely applied to the overall areas of orthopedics' education, research and clinic. It is also expected to be conveniently used in not only university hospitals but also regular general hospitals.

• Journal of Animal Science and Technology
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• v.54 no.3
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• pp.209-217
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• 2012

The objective of this study was to assess the external and internal quality traits of eggs in wholesale egg market in Colombo, Sri Lanka and the effect of storage period in egg quality traits in the same market after receiving the eggs. First, a total of 482 fresh eggs were randomly collected from the above market and external egg quality traits were determined and recorded according to the definitions given in the Specification for Chicken Egg SLS 959:1992. After that, a total of 288 fresh eggs were randomly collected and various external and internal egg quality traits were measured and recorded according to the standard procedures over a storage period of 1, 3 and 5 d after receiving the fresh eggs to the wholesale market. Information about the shops was also collected using a pretested questionnaire. Using the recorded data, shape index, Haugh unit, albumen index and yolk index were calculated for each egg. Average weight, width, length and shape index of the eggs in the sample was 59.96 g, 4.33 cm, 5.78 cm and 75.03, respectively. Average shape index value was much closer to the standard value of 74. From the total sample 80.5% eggs had a normal and sound shape. However only 60.37% of the eggs are in the desirable quality range specified in SLS 959:1992, when the overall shell quality of the sample is considered based on shell cleanliness, defects and shape. The results of the current study indicated that eggs had significant (p<0.05) deterioration of all internal quality parameters tested with increasing storage time. However the effect was not significant (p>0.05) between the storage periods of 3 and 5 d after receiving eggs except for yolk color and yolk height. Desirable category of eggs had reduced and rejections had increased with the storage period. Main problems associated with the particular market were less space availability, higher percentages of dirty eggs, unavailability of proper packaging materials, no standard packaging system for eggs, and not implementing a standard grading system for eggs. Therefore the results of this study suggest that proper egg handling and storage conditions such as low temperature storage may be implemented to increase the proportion of desirable quality eggs in the above market.

• Journal of Biomedical Engineering Research
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• v.16 no.4
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• pp.507-516
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• 1995

The nonstationary identifier in the DCT domain is suggested in this study for the identification of AR parameters of above-lesion upper-trunk electromyographic (EMG) signals as a means of developing a reliable real time signal to control functional electrical stimulation (FES) in paraplegics to enable primitive walking. As paraplegic shifts his posture from one attitude to another, there is transition period where the signal is clearly nonstationary. Also as muscle fatigues, nonstationarities become more prevalent even during stable postures. So, it requires a develpment of time varying nonstationary EMG signal identifier. In this paper, time varying nonstationary EMG signals are transformed into DCT domain and the transformed EMG signals are modeled and analyzed in the transform domain. In the DCT domain, we verified reduction of condition number and increment of the smallest eigenvalue of input correlation matrix that influences numerical properties and mean square error were compared with SLS algorithm, and the proposed algorithm is implemented using IMS T-805 parallel processing computer for real time application.

• Korean Journal of Food Science and Technology
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• v.35 no.5
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• pp.797-802
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• 2003

Structured lipids (SL) were synthesized by esterification of corn oil and conjugated linoleic acid (CLA) in a continuous packed-bed column reactor. The effects of flow rate, reaction temperature, and substrate molar ratios were studied. The reaction was catalyzed by TL IM (immobilized lipase from Thermomyces lanuginosa). Results of triacylglycerol (TAG) analysis by GC showed that the incorporated CLA isomers were mainly cis9, trans11- and trans 10, cis12-CLA. Slower flow rates yielded higher incorporation, and maximum incorporation of CLA was obtained with a molar ratio of 1:3 (corn oil: CLA) at a temperature of $55^{\circ}C$. The obtained SLs had iodine values ranging from 120 to 128. The SLs were composed of TAG $(98{\sim}99%)$, 1,2- and 1,3-diacylglycerol ($0.7{\sim}1.3%$), and a small amount of monoacylglycerol.

• Journal of Life Science
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• v.13 no.6
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• pp.805-813
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• 2003

cDNA encoding somatolactin (SL) was obtained by RT-PCR from pituitary glands of rock bream (Oplegnathus fasciatus). The full length cDNA of rock bream somatolactin (rbSL) is 1636 bp long. It contains a 696 bp open reading frame encoding a signal peptide of 24 amino acids (an) and a mature protein of 207 aa. rbSL has seven cysteine residues$(Cys^{5},\; Cys^{15},\; Cys^{42},\; Cys^{65},\; Cys^{181},\; Cys^{198}\; $and $Cys^{206})$ and two potential N-glycosylation sites at positions $Asn^{121}$and $Asn^{153}$. The rbSL shares 61.1∼92.6% amino acid sequence similarities and 63∼92.6% nucleotide sequence identities with other teleost SLs, except for goldfish and channel catfish SL. Amino acid sequence alignment revealed that rbSL has four conserved domains $(A_{SL},\; B_{SL},\; C_{SL}and\; D_{SL})$ common to all SLs. Out of these domains, $(A_{SL},\; B_{SL},\; C_{SL}and\; D_{SL})$, are also conserved in all teleost growth hormones and prolactins. The cDNA of rbSL has been cloned into pET expression vector in order to produce recombinant rbSL in E. coli BL2l(DE3) cells. The recombinant protein showed a molecular weight of 27 kDa in SDS-PAGE.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.112-119
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• 2016

This study aims to examine propping by the controlling shareholders and the corporate value of Korean firms with agency problems and propping perspectives. Propping refers to a transfer of resources from a higher ownership firm to a lower ownership firm, in order to prevent the latter from going bankrupt. This study used a sample of 4,077 companies listed on the KRX data exchange from 2004 to 2014. We used proxy variables such as long-term supply contracts, asset and business sales, credit facilities, loans, and equity investments to affiliates as wealth transfer instruments of the controlling shareholders. We found that propping occurred by the equity investment of affiliates in Korean firms. Also, we found that the Korean firm's value was decreased by the affiliate equity investment.

• Journal of Advanced Navigation Technology
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• v.17 no.6
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• pp.625-632
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• 2013

Since GBAS is a navaid facility to provide precision approach service to aircrafts landing at airports, it must be approved by the air navigation service provider or the aviation regulator to be declared operational. However, Korea has no experience in developing or operating the system so there is no approval criteria for GBAS. In order to develop the criteria in case of the future GBAS procurement, Korea Aerospace Research Institute has been testing the installed commercial GBAS station, SLS-4000, in Gimpo International Airport. This paper summarizes the criteria development results focusing on the system design approval. The criteria have been outlined based on the other leading nations' cases and documentations and established in detail on the basis of the FAA SDA artifacts. Those will be directly used for GBAS approval procedure in Korea and are expected to be useful in system requirement analysis, design, development and artifact management in case of own GNSS-based navaid system development in the future.

• Korean Journal of Food Science and Technology
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• v.53 no.6
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• pp.792-798
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• 2021

This study was conducted to determine the washing conditions in which surfactants were not detected after washing fruits and vegetables with detergent. Residual surfactants were analyzed using LC-MS/MS. The analyzed surfactants were LAS, SLES, AOS, SLS, CAPB, and LDAO. The survey found that 14% of the respondents used detergent correctly according to the directions indicated. After soaking the samples with 0.2% detergent, the average residual surfactant content was 2.61%. Soaking under 1% and 5% of the detergent, 4.68-5.50% of surfactant remained in the sample. In cherry tomatoes, the surfactants were below the LOD after rinsing twice. However, lettuce was rinsed three times. These results suggest that when using detergent for washing fruits and vegetables, following the labelled usage and rinsing at least three times in 30 seconds could minimize residual surfactants.

• Journal of Digital Convergence
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• v.19 no.5
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• pp.145-152
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• 2021

In this study, we have examined the effect of open innovation of SMEs on innovation performance of firms. Most studies do not consider internal generation in relation to open innovation and innovation performance.We conducted empirical studies to overcome this problem. The research was carried out by collecting data collected from 512 SMEs and the 3SLS method was used to minimize the internal generation. As a result, open innovation investment and use of external ideas among SMEs' open innovation have positively influenced project success and technical performance. But, the introduction of technology and cooperation with the research organization did not affect the innovation performance, which is presumed to be due to the fact that the open innovation of SMEs is limited to relatively inexpensive activities. Therefore, in order to promote open innovation of SMEs, it is necessary to provide support for relatively high-cost activities and to improve the innovation performance of enterprises. In order to reduce the difficulties of open innovation activities, domestic universities and research institutes should support the construction of enterprise networks and actively support the utilization of technology to expand innovation performance.