• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.6
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• pp.578-584
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• 2015

In this study a moving platform for a mobile robot that can be traveling with a full automatic standing arm was developed. Conventional mobile robots generally may equip 4 wheels or 3 wheels with a caster wheel or independent driven wheels and have good statistic stability. When a mobile robot travels on a sharply perpendicular and narrow crossroad, it may need a special steering scheme such as going forward and backward repeatedly or it is sometimes physically impossible for the robot to go through the crossroad because of the size limit. The upright running mobile robot changes its posture to the upright posture which has a small planar area and is able to go through the crossroad. The upright control which was manually performed step by step before such as sequences of uprighting (returning), checking, and balancing, is now automated.

• Journal of the Korea Furniture Society
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• v.28 no.2
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• pp.111-117
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• 2017

Recently, as people's interest in wood has increased, the use of wood as household and landscape decking materials has increased. As the deck material, imported wood such as synthetic wood, Ipe, and Malas was used in addition to the existing preserved wood, but recently deck use has been activated as part of the activation of domestic materials. As an important quality factor in the selection of such decking materials, various durability along with weatherability for long - term use is required for maintenance. Generally used tropical hardwoods have excellent weatherability and durability without additional preservative treatment. However, the domestic larch is a wood species with a higher specific gravity and durability than ordinary conifers. However, it has not yet been used as a deck material due to lack of comparative studies on its characteristics. Therefore, hardness and durability of wood were measured using six specimens of Ipe, Massaranduba, Malas, Douglas-fir, Larch and Torrefied-Larch. Density Profile was used to measure the density, and Brinell hardness test and resistance test against momentary impact were carried out for the test of resistance to static load. Also, The hardness and durability of wood were measured by castor test with resistance test against dynamic load, as well as, nail down test by experiment on surface hardness and durability. As a result of the experiment, the hardness was increased in proportion to the density, and it was confirmed that the imported lumber was harder and durable than the domestic larch.

• Journal of Korea Foundry Society
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• v.20 no.2
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• pp.122-128
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• 2000

Strip casting process is a new technology that makes a near net shape thin strip directly from molten metal. With this process, a large amount of energy and casting cost could be decreased from the abbreviation of reheating and/or hot rolling process. Ductile cast iron which has spheroidal graphite in the matrix is the most commercial and industrial material, because of its supreme strength, toughness, and wear resistance etc. But it cannot be produced to the thin strip owing to difficulty in rolling of ductile cast iron. In this study, ductile cast iron strips are produced by the twin roll strip caster, with different chemical compositions of C, Si, and Mn contents. And then heat-treated, microstructures and mechanical properties are examined. The microstructures of as-cast strip are that of white cast iron which consists of the mixture of cementite and pearlite, but the equiaxed crystal zone of the pearlite or segregation zone of cementite exists in the center region of the strip thickness, which cannot be observed in the rapidly solidified metallic mold cast specimens. This structure is supposed to be formed from the thermal distribution of strip and the rolling force. Comparing with the structures of each strips after heat treatment, increasing Si content makes smaller spheroidal graphite and more compact in the matrix, furthermore the less of Mn content makes the ferrite matrix be obtained clearer and easier. As a result of the tensile test of graphitization heat-treated strips, the yield strengths are about 250 MPa, the tensile strengths are about $430{\sim}500$ MPa, and the elongations are about $10{\sim}13%$. In the case of the strip which has the smaller and more compact spheroidal graphite in the ferrite matrix, the higher tensile strength and better drawability could be obtained.

• International Journal of Automotive Technology
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• v.6 no.2
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• pp.183-190
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• 2005

During normal operating conditions, a motor vehicle is constantly subjected to a variety of forces, which can adversely affect its straight-ahead motion performance. These forces can originate both from external sources such as wind and road and from on-board sources such as tires, suspension, and chassis configuration. One of the effects of these disturbances is the phenomenon of vehicle lateral-drift during straight-ahead motion. This paper examines the effects of road crown, tires, and suspension on vehicle straight-ahead motion. The results of experimental studies into the effects of these on-board and external disturbances are extremely sensitive to small changes in test conditions and are therefore difficult to guarantee repeatability. This study was therefore conducted by means of computer simulation using a full vehicle model. The purpose of this paper is to gain further understanding of the straight-ahead maneuver from simulation results, some aspects of which may not be obtainable from experimental study. This paper also aims to clarify some of the disputable arguments on the theories of vehicle straight-ahead motion found in the literature. Tire residual aligning torque, road crown angle, scrub radius and caster angle in suspension geometry, were selected as the study variables. The effects of these variables on straight-ahead motion were evaluated from the straight-ahead motion simulation results during a 100m run in free control mode. Examination of vehicle behavior during straight-ahead motion under a fixed control mode was also carried out in order to evaluate the validity of several disputable arguments on vehicle pull theory, found in the literature. Finally, qualitative comparisons between the simulation results and the test results were made to support the validity of the simulation results.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.24 no.3
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• pp.35-42
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• 1979

Experiments were conducted to find out the labor saving efficiency and optimum seeding rate and fertilizer level when newly invented Barley Rotor Caster was used in wheat sowing on paddy field. It decreased the labor for sowing by 66~77% compared with conventional sowing method. And the optimum. seeding rate was considered to be approximately 20$\ell$Q per 10a in standard fertilizer level and optimum fertilizer level to be 18-12-12kg/10a, $N-P_2O_5-K_2O$ respectively.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.5
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• pp.353-359
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• 2010

Introduction: This study examined the effect of cyclosporine A (CsA) on the allogenic cranial bone graft in the mice. Materials and Methods: Twenty eight 12-week-old male ICR mice weighing 40 g were used. The experimental group was injected subcutaneously with CsA (10 mg/kg/day) diluted in Caster oil for 7 days prior to the graft until sacrifice. The control group was injected with the same solution without CsA. Two full-thickness bone defects with a diameter of 3 mm were made with a trephine bur in the parietal bone lateral to the sagittal suture. A calvarial defect of a mouse was grafted with allogenic calvarial bone disc from another mouse. The experimental and control groups were injected with CsA and the solution without CsA in the same manner before surgery, respectively. The mice were sacrificed at 1 week, 2 weeks and 4 weeks after the bone graft, respectively. Results: In the experimental group, fibrous connective tissues and small amounts of inflammatory cells were observed. At 2 weeks after the allograft in the experimental group, new bone formation in fibrous collagenous tissue and around the allogenic bone was noted. At 4 weeks after the allograft, new bone formation was active along and at the periphery of the mature allogenic bone. The proliferation of blood vessels increased in bone marrow. In the control group, fibrous tissues and inflammatory cells were observed around the allogenic bone and existing bone at 1 week. At 2 weeks after the allograft, the proliferation of blood vessels accompanied by inflammatory cells were scattered in the fibrous connective tissues. New bone formation around the allogenic and existing bone could be observed. At 4 weeks after the allograft, inflammatory cells were severely infiltrated around the allogenic bone. Osteoclasts were scattered along the allogenic bone and induced bone resorption. Conclusion: These results suggest that the daily administration of CsA (10 mg/kg/day) induces efficient immunosuppression without serious complications, and this protocol might be useful for the experimental model of allogenic bone grafts.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.851-860
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• 2020

With an increase in the aging population and a rising social interest in health and welfare, studies to improve healthcare in the elderly are being actively conducted. This study attempted to improve the current design and manufacture of elevating electric wheelchairs to enhance user safety and convenience. Seat design based on the user's body shape, convenience while boarding or alighting, caster turning radius and, safety and stability features that prevent shaking when the user gets up or sits down were improved. A driving experiment was conducted to evaluate the operation of the indoor electric wheelchair designed and manufactured with these additional functionalities. During the test, the performance parameters evaluated were continuous driving time, turning radius, maximum lifting and lowering load, maximum lifting height, noise level, minimum distance sensing by the driving auxiliary sensor, ability to interact with server and app programs, and the duty cycle maximum error rate. The test confirmed that this improved electric wheelchair successfully met target parameters. In a future study, we will evaluate this improved electric wheelchair from a user's perspective for its usability parameters, such as satisfaction, convenience and stability.

• Journal of the Korea Organic Resources Recycling Association
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• v.25 no.2
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• pp.49-57
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• 2017

The consumption of KimChi, which Korean are a favorite food, has dramatically increased by changes of life style and waste as by-products in KimChi factory. This study was conducted to evaluate an effect of compost of caster oil cake (COC) mixed with waste from KimChi factory (KWF) and its growth effect of lettuce. Treatments were consisted of 4 treatments as COC compost (60% COC+40% sawdust) as control, control+35% KWF (K-1), control+50% KWF (K-2), and control+65% KWF (K-3). Temperature, pH, O.M. and microbial phase of COC composts blended various ratios of KWF or free were unaffected. It was appeared that nitrogen content of KWF treatments was higher, but the ratio of organic matter and nitrogen was lower than the control. Although KWF treatments were acceptable compost under the guideline of Korean, NaCl content of K-3 was 1.91%, and it was very higher than that of others. In comparison with fresh weight and dry weight of lettuce, K-1 and K-3 were similar to control. These results indicated that the waste from KimChi factory was possible to use the composting raw blended materials below 35% mixtures.

• The Journal of Internal Korean Medicine
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• v.27 no.2
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• pp.356-370
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• 2006

Objectives: The aim of this experimental study is to investigate effects of Dolichoris Semen, Terminaliae Fructus and Bojanggunbi-tangon the anti-cathartic action of mice and guinea pigs to develop effective herbal medicine and prescription to cure diarrhea early and to prevent side effect of chronic diarrhea. Methods: To compare effects of Dolichoris Semen, Terminaliae Fructus and Bojanggunbi-tangon the anti-cathartic action of mice and guinea pigs, we evaluated the actions on isolated gastrointestinal smooth muscles. on the transportability of small and large intestines, onthe neostigmine-induced transportability of small intestine and on diarrhea induced by castor oil, pilocarpine, barium chloride. Results: (1) Dolichoris Semen, Terminaliae Fructus and Bojanggunbi-tang showed the strong alleviation on the contraction of mice's isolated gastrointestinal smooth muscles induced by acetylcholine chloride and barium chloride. while Terminaliae Fructus, strong, Bojanggunbi-tang, intermediate and Dolichoris Semenshowed the minor alleviation on the contraction of guinea pigs' isolated gastrointestinal smooth muscles induced by acetylcholine chloride and histamine. All effects depended on the density in each medicine. (2) The tranbportability of small intestine was contrained in the groups controlled by 600 mg/kg of Dolichoris Semen, Terminaliae Fructus and Bojanggunbi-tang, and 200 mg/kg of D olichoris Semen and Terminaliae Fructus. However, the enhancement of neostigmine-induced transportability of small intestine was constrained only in the groups controlled by 600 mg/kg of Dolichoris Semen, Terminaliae Fructus and Boianggunbi-tang. (3) The transportability of large intestine was constrained by Dolichoris Semen and Bojanggunbi-tang. They showed substantial results. which depended on the amount of each medicine. (4) Terminaliae Fructus showed substantial anti-cathartic effects on diarrhea induced by caster oil in both groups controlled by 200 and 600 mg/kg of it. However, Bojanggunbi-tangshowed the effects only in the group controlled by 600 mg/kg. in diarrhea induced by pilocarpine, the groups controlled by 600 mg/kg or Terminaliae Fructus and 200 and 600 mg/kg of Boianggnbi-tangshowed substantial results. In diarrhea induced by barium chloride. the groups controlled by 200 and 600 mg/kg of Terminaliae Fructus and 600 mg/kg of Boianggunbi-tangshowed substantial results in anti-cathartic effects. Conclusions: These results show that Terminaliae Fructus is more effective on the contraction of mice and guinea pigs' isolated gastrointestinal smooth muscles, Dolichoris Semen is more effective on the transportability of small intestine, Dolichoris Semen and Bojanggunbi-tang are more effective on the transportability of large intestine. Terminaliae Fructus and Bojanggunbi-tang show substantial results in anti-cathartic actions.

• Journal of Korean Society for Geospatial Information Science
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• v.23 no.3
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• pp.31-39
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• 2015

This paper presents the static and kinematic positioning accuracy by the real-time GPS positioning modes of the low-cost GPS receivers using NTRIP-based augmentation service. For this, acquires both the raw measurements data of the field tests by LEA 6T GPS module of u-blox AG, and correction communication via NTRIP caster with RTKLIB as an open source program for GNSS solution. With computing the positions of the check points and road tracks by six kinds of GPS positioning modes which are Single, SBAS, DGPS, PPP, RTK, and TCP/IP_RTK, compared these results to the reference position of the check points. The position error average and rmse of the static test by GPS L1 RTK surveying showed $N=0.002m{\pm}0.001m$, $E=0.004m{\pm}0.001m$ in horizontal plane, and $h=-0.116m{\pm}0.003m$ in vertical, these results are very closed to the coordinates with the geodetic receiver. Especially, in case of the kinematic test with obstacles located on both sides of road, the computed track with ambiguity fixing showed very similar trajectory considerably from VRS network RTK mode. And also, evaluate and verify the performance of the TCP/IP_RTK mode developed based on TCP/IP protocol.