• Journal of the Korean Society for Precision Engineering
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• v.12 no.6
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• pp.13-19
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• 1995

A dual purpose robot automation system is developed for both arc welding and spot welding by one robot within a cell. The need for automation of both arc welding and spot welding processes is urgent while the production volume is not so big as to accommodate separate stations for the two processes. Also, space is too narrow for separate stations to be settled down in the factory. A spot welding robot is chosen and the functions for arc welding are implemented in-house at cost of advanced functions. For the spot welding, a single pole type gun is used and the robot has to push down the plate to be wolded, which causes the robot positioning error. Therefore, position error compensation algorithm is developed. The basic functions for the arc welding processes are implemented using the digital I/O board of robot controller, PLC, and A/D conversion PCB. The weaving pattern is taught in meticulously by manual teach. A fixture unit is also developed for dual purpose. The main aspects of the system is presented in this paper especially in the design and implementation procedure. The signal diagrams and sequence logic diagrams are also included. The outcome of the dual purpose welding cell is the increased productivity and good production stability which is indispensable for production volume prediction. Also, it leads to reduction of manufacturing lead time.

• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.803-809
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• 2023

This paper analyzes and evaluates to optimally build a data collection system essential for factory energy management systems on an edge-based lightweight platform. A "Sensor/OPC-UA simulator" was developed based on sensors in an actual food factory and used to evaluate the storage engine of edge devices. The performance of storage engines in edge devices was evaluated to suggest the optimal storage engine. The experimental results show that when using the RocksDB storage engine, it has less than half the memory and database size compared to using InnoDB, and has a 3.01 times faster processing time. This study enables the selection of advantageous storage engines for managing time-series data on devices with limited resources and contributes to further research in this field through the sensor/OPC simulator.

• Journal of the Korean Society for Library and Information Science
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• v.58 no.1
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• pp.181-198
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• 2024

As the teaching and learning paradigm shifts, the demand for informal learning is increasing. In this study, we reviewed related literature and analyzed cases of operating professional learning communities in order to apply professional learning communities to librarianship education and training programs. Seven operational cases of professional learning communities, both domestic and foreign, within the field of librarianship and other fields were selected. The organizational structure, operational format and method, learning content, and support systems were analyzed. Through this analysis, the concept of a librarian learning community was defined, and implications for organizing and operating a librarian learning community were derived from the spontaneity and multi-layeredness of composition, diversity of learning community operation formats, and fieldality of learning content. As a support system for the smooth operation and activation of the librarian learning communities continuity of program operation by the operating organization, support and cooperation from affiliated organizations, education and training programs, platform establishment and operation, and dissemination and feedback of results for activation were presented.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.2
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• pp.200-207
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• 2015

Various natural products or their derivatives, mostly originating from plants, fungi, and bacteria, have been exploited as therapeutic drugs to treat various human diseases. In addition to previously explored organisms, research on natural compounds has now expanded into unexamined living organisms in order to identify novel bioactive substances. Here, we determined whether or not the larval form of the mealworm beetle Tenebrio molitor, a species of darkling beetle, contains cytotoxic substances that exclusively affect cancer cell viability. Ethanol extract and its solvent partitioned fractions, hexane and ethyl acetate fractions, showed anticancer effects against various human cancer cells derived from the prostate (PC3 and 22Rv1), cervix (HeLa), liver (PLC/PRF5, HepG2, Hep3B, and SK-HEP-1), colon (HCT116), lung (NCI-H460), breast (MDA-MB231), and ovary (SKOV3). Cell death induced by the fractions was a mix of apoptosis, necrosis, and autophagy. The hexane fraction was administered intraperitoneally to nude mice bearing a hepatocellular carcinoma SK-HEP-1 and showed inhibition of tumor growth in vivo. Therefore, we concluded that worm extracts contain cytotoxic substances, which can be enriched by proper fractionation protocols, and further separation and purification could lead to the identification of novel molecules to treat human cancers.

• International Journal of Ocean System Engineering
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• v.2 no.3
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• pp.185-194
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• 2012

A Macroscopic combination of two or more distinct materials is commonly referred to as a "Composite Material", having been designed mechanically and chemically superior in function and characteristic than its individual constituent materials. Composite materials are used not only for aerospace and military, but also heavily used in boat/ship building and general composite industries which we are seeing increasingly more. Regardless of the various applications for composite materials, the industry is still limited and requires better fabrication technology and methodology in order to expand and grow. An example of this is that the majority of fabrication facilities nearby still use an antiquated wet lay-up process where fabrication still requires manual hand labor in a 3D environment impeding productivity of composite product design advancement. As an expert in the advanced composites field, I have developed fabrication skills with the use of machinery based on my past composite experience. In autumn 2011, the Korea government confirmed to fund my project. It is the development of a composite sanding machine. I began development of this semi-robotic prototype beginning in 2009. It has possibilities of replacing or augmenting the exhaustive and difficult jobs performed by human hands, such as sanding, grinding, blasting, and polishing in most often, very awkward conditions, and is also will boost productivity, improve surface quality, cut abrasive costs, eliminate vibration injuries, and protect workers from exposure to dust and airborne contamination. Ease of control and operation of the equipment in or outside of the sanding room is a key benefit to end-users. It will prove to be much more economical than normal robotics and minimize errors that commonly occur in factories. The key components and their technologies are a 360 degree rotational shoulder and a wrist that is controlled under PLC controller and joystick manual mode. Development on both of the key modules is complete and are now operational. The Korean government fund boosted my development and I expect to complete full scale development no later than 3rd quarter 2012. Even with the advantages of composite materials, there is still the need to repair or to maintain composite products with a higher level of technology. I have learned many composite repair skills on composite airframe since many composite fabrication skills including repair, requires training for non aerospace applications. The wind energy market is now requiring much larger blades in order to generate more electrical energy for wind farms. One single blade is commonly 50 meters or longer now. When a wind blade becomes damaged from external forces, on-site repair is required on the columns even under strong wind and freezing temperature conditions. In order to correctly obtain polymerization, the repair must be performed on the damaged area within a very limited time. The use of pre-impregnated glass fabric and heating silicone pad and a hot bonder acting precise heating control are surely required.

• Investigative Magnetic Resonance Imaging
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• v.18 no.3
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• pp.232-243
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• 2014

Purpose : To evaluate the incidence of secondary contiguous or non-contiguous subchondral bone impactions (SBI) in subaxial cervical spinal injury and associated primary injury patterns. Materials and Methods: A retrospective review of computed tomography, magnetic resonance imaging, and medical records was carried out for 47 patients who had sustained a subaxial cervical spinal injury. Presence, number, level, and sites of secondary contiguous or non-contiguous SBI were recorded. To evaluate primary injury patterns, the level and number of primary injury sites of subaxial cervical spine injury, injury morphology, anterior/posterior discoligamentous complex (ADC/PDC) injury, posterior ligamentous complex (PLC) injury, spinal cord injury, and mechanism of injury (MOI) were analyzed. Differences in primary injury pattern of subaxial cervical spine injury and MOI between patients with and without SBI, and between contiguous or non-contiguous SBI were analyzed using the Mann-Whitney U test, Pearson's chi square test and Fisher's exact test. Results: Eighteen patients (18/47, 38.29%) had developed contiguous (n=9) or non-contiguous (n=9) SBI, most commonly involving T3 (15/47, 31.91%) and 3 levels (6/18, 33.33%). All SBIs had developed near the anterosuperior region of the body and the superior endplate and were the result of a high-impact MOI. SBIs were statistically significant in association with injury morphology and PLC injury (P=0.001, P=0.009, respectively) at the primary injury site. Non-contiguous SBI was more frequently accompanied by upper cervical spinal injuries in association with PDC injuries, as opposed to contiguous SBI, with statistical significance (P=0.009), while no other statistically significant differences were found. Conclusion: Secondary SBIs are common and probably associated with subaxial cervical spinal injuries with high energy compressive flexion forces.

• Journal of Life Science
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• v.21 no.11
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• pp.1607-1611
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• 2011

To analyze the role of Bombyx mori transferrin (BmTf) in response to microbes or oxidative stress, we investigated the level of BmTf transcripts in B. mori treated with various microbes and oxidative stress inducers. BmTf mRNA was mainly expressed in the epidermis and fat in the bodies of B. mori injected with Escherichia coli, and up regulated in response to microbes such as bacteria, fungi, or viruses, but was hardly altered in response to oxidative stress inducers such as $H_2O_2$, Cu, or $FeCl_3$. We also confirmed that BmTf mRNA expression was increased in Bm5 cells treated with ERK, PLC, PKA, PI3K, MAPK, or JNK inhibitors, respectively. To identify the major inducer of BmTf expression, we analyzed the amount of serum iron in the hemolymph of B. mori after injection or feeding with E. coli or $FeCl_3$. The results showed that the amount of serum iron was not changed by injection and feeding with E. coli, although BmTf mRNA was increased by injection with E. coli. On the contrary, injection and feeding with $FeCl_3$ significantly increased the amount of serum iron, although they did not alter the BmTf mRNA level. On the basis of these results, we assume that up-regulation of BmTf in B. mori is closely related to the defense of microorganism, and BmTf may be expressed at the basal constitutive level when it plays a role in iron metabolism by maintaining iron homeostasis and in the insect defense mechanism against oxidative stress.

• Journal of Life Science
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• v.31 no.9
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• pp.787-795
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• 2021

Eupatorium chinensis var. simplicifolium (EUC) has anti-inflammatory and antioxidant effects. Young sprouts of EUC have been used as food for a long time, and the whole EUC plant has been used as an herbal remedy in oriental medicine. Arteriosclerosis, or chronic inflammation in arterial vessels, is a cardiovascular disease and is involved in various disorders. Cardiovascular diseases such as restenosis and neuropathic hyperplasia are mainly caused by abnormal growth and movement due to multiple growth factors in vascular smooth muscle cells (VSMCs). Platelet-derived growth factor (PDGF) is a mitogen released from damaged vessel walls and is involved in the proliferation and migration of VSMCs. To determine the effects of EUC on the abnormal proliferation and migration of VSMCs, the present study investigated intracellular signaling pathways in PDGF-BB-induced VSMCs treated with and without EUC. Pretreating PDGF-BB-induced VSMCs with EUC tended to effectively decrease cell proliferation and migration. Subsequently, the intracellular growth-related signaling pathways of AKT, phospholipase C gamma (PLC-γ), and mitogen-activated protein kinase (MAPK) were investigated using western blotting to confirm inhibited phosphorylation. Furthermore, flow cytometry data showed that EUC blocked the cell cycle of VSMCs. These results suggest that EUC can inhibit the proliferation and migration of VSMCs by controlling the cell cycle and growth factor receptors. Furthermore, this indicates that EUC can be used as a preventative against cardiovascular disease resulting from abnormal proliferation and migration of VSMCs.

• Journal of IKEEE
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• v.27 no.1
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• pp.122-126
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• 2023

In this paper, a control system for a complex microbial incubator was proposed. The proposed control system consists of a control unit, a communication unit, a power supply unit, and a control system of the complex microbial incubator. The controller of the complex microbial incubator is designed and manufactured to convert analog signals and digital signals, and control signals of sensors such as displays using LCD panels, water level sensors, temperature sensors, and pH concentration sensors. The water level sensor used is designed and manufactured to enable accurate water level measurement by using the IR laser method with excellent linearity in order to solve the problem that existing water level sensors are difficult to measure due to foreign substances such as bubbles. The temperature sensor is designed and used so that it has high accuracy and no cumulative resistance error by measuring using the thermal resistance principle. The communication unit consists of two LAN ports and one RS-232 port, and is designed and manufactured to transmit signals such as LCD panel, PCT panel, and load cell controller used in the complex microbial incubator to the control unit. The power supply unit is designed and manufactured to supply power by configuring it with three voltage supply terminals such as 24V, 12V and 5V so that the control unit and communication unit can operate smoothly. The control system of the complex microbial incubator uses PLC to control sensor values such as pH concentration sensor, temperature sensor, and water level sensor, and the operation of circulation pump, circulation valve, rotary pump, and inverter load cell used for cultivation. In order to evaluate the performance of the control system of the proposed complex microbial incubator, the result of the experiment conducted by the accredited certification body showed that the range of water level measurement sensitivity was -0.41mm~1.59mm, and the range of change in water temperature was ±0.41℃, which is currently commercially available. It was confirmed that the product operates with better performance than the performance of the products. Therefore, the effectiveness of the control system of the complex microbial incubator proposed in this paper was demonstrated.

• Asia Marketing Journal
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• v.10 no.2
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• pp.1-29
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• 2008

The objective of our study is to provide an exploratory model for forecasting sales take-off timing of a product in the context of multi-national markets. We evaluated the usefulness of key predictors such as multiple market information, product attributes, price, and sales for the forecasting of sales take-off timing by applying the suggested model to monthly sales data for PDP and LCD TV provided by a Korean electronics manufacturer. We have found some important results for global companies from the empirical analysis. Firstly, innovation coefficients obtained from sales data of a particular product in other markets can provide the most useful information on sales take-off timing of the product in a target market. However, imitation coefficients obtained from the sales data of a particular product in the target market and other markets are not useful for sales take-off timing of the product in the target market. Secondly, price and product attributes significantly influence on take-off timing. It is noteworthy that the ratio of the price of the target product to the average price of the market is more important than the price ofthe target product itself. Lastly, the cumulative sales of the product are still useful for the prediction of sales take-off timing. Our model outperformed the average model in terms of hit-rate.