• Journal of Institute of Control, Robotics and Systems
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• v.7 no.9
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• pp.717-722
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• 2001

This paper presents a methodology on the backward path tracking control of a trailer type robot which consists of two parts: a tractor and a trailer. It is difficult to control the motion of a trailer vehicle since its dynamics is non-holonomic. Therefore, in this paper, the modeling and parameter estimation of the system using a real-coded genetic algorithm(RCGA) is proposed and a backward path tracking control algorithm is then obtained based on the linearized model. Experimental results verify the effectiveness of the proposed method.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.1
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• pp.1-7
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• 2011

Purpose: The purpose of this study was to investigate the cutting efficiency of coarse grit diamond burs with air-turbine handpiece on natural tooth. Materials and methods: Four groups of coarse grit diamond bur were selected: Komet (A), Shofu (B), Premier (C), and Mani (D). The extracted maxillary central incisors were used, and ten cuts were made on each specimen, using the rotary diamond burs. The surface of each bur was measured at the upper, middle, and bottom of the bur with confocal laser scanning microscope and imaged with SEM. The data were analyzed with one-way ANOVA and t-test at the significance level of 0.05. Results: The surface roughness was measured. At the A diamond bur, the Sa values were $52.93\;{\mu}m$, $48.32\;{\mu}m$, $46.79\;{\mu}m$, $45.06\;{\mu}m$, and $43.43\;{\mu}m$ for control, test 1, 2, 3, and 4 respectively. The Sa values were $50.68\;{\mu}m$, $45.62\;{\mu}m$, $44.41\;{\mu}m$, $44.10\;{\mu}m$, and $42.46\;{\mu}m$ for B diamond bur, $58.02\;{\mu}m$, $55.53\;{\mu}m$, $52.22\;{\mu}m$, $48.26\;{\mu}m$, and $45.36\;{\mu}m$ for C diamond bur, and $50.11\;{\mu}m$, $46.73\;{\mu}m$, $45.46\;{\mu}m$, $42.58\;{\mu}m$, and $41.80\;{\mu}m$ for D diamond bur. Surface roughness after each bur use showed significant changes, but no significant difference was found in surface roughness change between bur systems. Conclusions: Surface roughness in the same bur system showed significant differences after each tooth preparation. However no statistically significant differences were found in surface roughness between bur systems. The SEM images between control and test 4 showed the abraded particles.

• The Journal of Korean Society for Radiation Therapy
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• v.30 no.1_2
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• pp.161-167
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• 2018

Purpose : This study evaluates the usefulness of the Modified Hybrid-VMAT scheme with consideration of background radiation when establishing a treatment plan for multiple bone metastatic cancer including multiple tumors on the same axis. Materials and Methods : The subjects of this study consisted of five patients with multiple bone metastatic cancer on the same axis. The planning target volume(PTV) prescription dose was 30 Gy, and the treatment plan was established using Ray Station(Ray station, 5.0.2.35, Sweden). In the treatment plan for each patient, two or more tumors were set as one isocenter. A volumetric modulated arc therapy(VMAT) plan, a hybrid VMAT(h) plan with no consideration of background radiation, and a modified hybrid VMAT(mh) with consideration of background radiation were established. Then, using each dose volume histogram(DVH), the PTV maximum dose($D_{max}$), mean dose($D_{mean}$), conformity index(CI), and homogeneity index(HI) were compared among the plans. In addition, the organ at risk(OAR) of each treatment site was evaluated, and the total MU(Monitor Unit) and treatment time were also analyzed. Results : The PTV $D_{max}$ values of VMAT, VMAT(h) and VMAT(mh) were 3188.33 cGy, 3526 cGy, and 3285.67 cGy, the $D_{mean}$ values were 3081 cGy, 3252 cGy, and 3094 cGy; the CI values were $1.35{\pm}0.19$, $1.43{\pm}0.12$, and $1.30{\pm}0.06$; the HI values were $1.06{\pm}0.01$, $1.14{\pm}0.06$, and $1.09{\pm}0.02$; and the VMAT(h) OAR value was increased 3 %, and VMAT(mh) OAR value was decreased 18 %, respectively. Furthermore, the mean MU values were 904.90, 911.73, and 1202.13, and the mean beam on times were $128.67{\pm}10.97$, $167.33{\pm}7.57$, and $190.33{\pm}4.51$ respectively. Conclusions : Applying Modified Hybrid-VMAT when treating multiple targets can prevent overdose by correcting the overlapping of doses. Furthermore, it is possible to establish a treatment plan that can protect surrounding normal organs more effectively while satisfying the inclusion of PTV dose. Long-term follow-up of many patients is necessary to confirm the clinical efficacy of Modified Hybrid-VMAT.

• Radiation Oncology Journal
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• v.19 no.2
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• pp.199-204
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• 2001

Purpoe : To find the optimal values of total arc degree to protect the normal brain tissue from high dose radiation in stereotactic radiotherapy planning. Methods and Materials : With Xknife-3 planning system & 4 MV linear accelerator, the authors planned under various values of parameters. One isocenter, 12, 20, 30, 40, 50, and 60 mm of collimator diameters, $100^{\circ},\;200^{\circ},\;300^{\circ},\;400^{\circ}C,\;500^{\circ},\;600^{\circ}$ or total arc degrees, and $30^{\circ}\;or\;45^{\circ}$ or arc intervals were used. After the completion of planning, the plans were compared each other using $V_{50}$ (the volume of normal brain that is delivered high dose radiation) and integral biologically effective dose. Results : At $30^{\circ}$ of arc interval, the values of $V_{50}$ had the decreased pattern with the increase of total arc degree in any collimator diameter. At 45 arc interval, up to $400^{\circ}$ of total arc degree, the values of $ V_{50}$ decreased with the increase of total arc degree, but at $500^{\circ}\;and\;600^{\circ}$ of total arc degrees, the values increased. At $30^{\circ}$ of arc interval, integral biologically effective dose showed the decreased pattern with the increase of total arc degree in any collimator diameter. At $45^{\circ}$ arc interval with less than 40 mm collimator diameter, the integral biologically effective dose decreased with the increase of total arc degree, but with n and n mm or collimator diameters, up to $400^{\circ}$ or total arc degree, integral biologically effective dose decreased with the increase of total arc degree, but at $500^{\circ}\;and\;600^{\circ}$ of total arc degrees, the values increased. Conclusion : In the stereotactic radiotherapy planning for brain lesions, planning with $400^{\circ}$ of total arc degree is optimal. Especially, when the larger collimator more than 50 mm diameter should be used, the uses of $500^{\circ}\;and\;600^{\circ}$ of total arc degrees make the increase of$V_{50}$ and integral biologically effective dose. Therefore stereotactic radiotherapy planning using $400^{\circ}$ of total arc degree can increase the therapeutic ratio and produce the effective outcome in the management of personal and mechanical sources in radiotherapy department.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.3
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• pp.335-341
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• 2013

Kyungokgos purchased in local markets in Korea vary in their combination and mixing ratios during processing. This study was investigated qualities of Kyungokgos manufactured traditionally to evaluating its qualities. The general components of Kyungokgos were moisture (18.62~49.78%), ash (0.198~1.211%), protein (0.89~3.58%), lipid (0.16~1.14%) and carbohydrates (47.95~77.08%). The color values of L, a, and b were 26.49~73.87, 16.51~38.64, and 45.41~88.94, respectively. The viscosity was classified into three non-Newtonian type groups: high, medium, and non-dilatant, according to the increase of loop execution times. Three extracts (KOG-1, -7, and -8, in a 30-fold dilution) showed no cytotoxicity toward RAW 264.7 cells, while the extracts of KOG-2, -4, and -5 showed a low cytotoxic effect. KOG-1 and -2 extracts with low cytotoxicity markedly inhibited the production of the inflammatory mediators-nitric oxide (NO) and tumor necrosis factor-alpha (TNF-${\alpha}$) in LPS-stimulated RAW 264.7 cells. These results indicate that KOG-1 and -2 extracts have anti-inflammatory activity in LPS-stimulated RAW 264.7 macrophages.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.12
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• pp.1769-1775
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• 2016

Aerial parts (leaves and stems) of radish are usually discarded due to the distinct undesirable flavors associated with inappropriate preparations, despite their many health benefits. In this study, we examined the role of extrusion process in the removal of off-flavors and elevation of antioxidant activity in radish (Raphanus sativus L.) leaves and stems. To optimize the extrusion conditions, we changed the barrel temperature (110, 120, and $130^{\circ}C$), screw speed (150, 200, 250, and 300 rpm), and moisture content (20, 25, and 30%). The polyphenol and flavonoid contents significantly increased in extruded radish leaves and stems (ER) under optimum extrusion conditions ($130^{\circ}C$, 250 rpm, and 20%). Under extrusion conditions, we compared off-flavors (as amount of sulfur-containing compound) levels between ER and non-extruded radish leaves and stems (NER) by an electronic nose. A total of six peaks (sulfur-containing compound) were similarly detected in both ER and NER, whereas the ER showed reduced off-flavors. Levels of glucosinolate (${\mu}g/g$), which can be hydrolyzed into off-flavors during mastication or processing, were significantly decreased in the ER. From these results, extrusion processing can be an effective method to increase anti-oxidant activity and removal of off-flavors in radish leaves and stems.

• Journal of Animal Environmental Science
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• v.8 no.1
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• pp.9-16
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• 2002

This study was conducted to develope the new solid separating system which can be efficiently and economically removed the solid parts in high pollutants concentration of pig slurry. The pollutants concentration, BOD$_{5}$ , COD and SS of the slurry used in this study was 15,990($\pm$2,389)mg/l, 20,004($\pm$5,512)mg/l and 26,486($\pm$5,935)mg/l, respectively. After removal of solid part in slurry, the pollutants concentration, BOD$_{5}$, COD and SS was change into 5,617($\pm$690)mg/l, 5,553($\pm$633)mg/land 1,456($\pm$341)mg/l, respectively in the Fixed biological membrane tank. The reduction of the pollutants concentration of suspend liquid through membrane will be allowed to greatly improve the water purification by an Activated sludge method. This separating system consisted of a temporary storage, a circulating tank and a Fixed Biological membrane tank. A temporary storage which has a draining system of screw type and an aeration device played a tremendous role in draining the solid by filled an aeration of 0.3 l/min. A Fixed Biological membrane tank of which a styrofoam filled in a 2/3 volume as a Biological media was fixed by a stainless steel net (pore size : 0.5mm) to separate the liquid layer of influx in them. The separating system efficiency factors were the speed of screw motor, cycle number of slurries in a circulating tank and moisture contents of solid effluent through the screw path. Although the pollutants concentration was very variable in temporary storage, the final concentration of $BOD_5$ and SS, except COD of the suspended liquid in a Fixed biological membrane were not different regardless of cycle number of a circulating tank. Moisture contents of effluent from temporary storage was 73% under the speed 1 ppm of screw motor and 62% under the 1/4rpm of it.

• Korean Journal of Organic Agriculture
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• v.25 no.4
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• pp.843-859
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• 2017

The JK-1 isolate which was the best producer of indole-3-acetic acid and carotenoid among the 388 strains isolated from 28 wetlands in Jeju, was identified to be Rhodopseudomonas palustirs belongs to a typical group of non sulfur purple bacteria based on 16S sRNA sequencing. This study investigated the effect of different cultural conditions of pH, temperature, agitation, light and aeration on growth, IAA and carotenoid production of photosynthetic bacterium JK-1 for optimization of IAA and carotenoid production. It was found that growth, IAA, carotenoid, and bacteriochlorophyll production with light (3,000~3,500 Lux) and agitation (100 rpm) showed better results than those with dark/static or dark/agitation (100 rpm) in anaerobic conditions. The optimal pH, temperature and agitation speed for cell growth were 7, $30^{\circ}C$, 150 rpm, for IAA production were 9, $30^{\circ}C$, 150rpm and for carotenoid production were 6, $25^{\circ}C$, 50 rpm, cultured for 72 h under anaerobic light, respectively. The growth and IAA production were high in aerobic culture compared with anaerocic culture, whereas carotenoid and bacteriochlorophyll content were decreased extremely in aerobic condition (0.5~1 vvm). Subsequently, the optimal culture conditions for JK-1 were selected with pH 7, $30^{\circ}C$ and 100 rpm under anaerobic light and the effect on plant growth was tested by pot assay. Inoculation of JK-1 with 3% (v/v) level caused increase in shoot and root dry weigh that varied from 20%~58% to 40%~28% in young radish in camparison to uninoculated treatment at 50 days of growth. The study suggests that the JK-1 isolate may serve as efficient biofertilizer inoculants to promote plant growth.

• Radiation Oncology Journal
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• v.19 no.1
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• pp.1-9
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• 2001

Purpose : To establish the role of stereotactic radiosurgery (SRS) for the treatment of patients with angiographically occult vascular malformation (AOVM). Materials and Methods : Eleven patients (12 lesions) with AOVM were treated with linear accelerator-based SRS between February 1995 and December 1999. A magnetic resonance imaging of each patients showed well-circumscribed vascular lesion with reticulated core of heterogeneous signal intensity and peripheral rim of low signal intensity. SRS were peformed with the median peripheral dose of 16 Gy (range 13~25). A single isocenter was used with median collimator size of 14 mm (range 8~20) diameter. Results : With a median follow-up period of 42 months (range 12~56), rebleeding occurred in 3 AOVMS at 5, 6 and 12 months after SRS but no further bleeding did. Two patients experienced radiation-induced necrosis associated with permanent neurologic deficit and one patient showed transient edema of increased 72 signal intensity. Conclusion : SRS may be effective for the prevention of rebleeding in AOVM located in surgically inaccessible region of the brain. Careful consideration should be needed in the decision of case selection and dose prescription because the incidence of radiation-induced complications is too high to be accepted.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.17 no.2
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• pp.93-103
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• 1981

It is well-known that nowadays heat resisting and anti-corrosive materials have been widely used as the components materials of gas turbines, nuclear power plants and engines etc. In the fields of machine production industry. And materials for engine components, like as the exhaust valve of internal combustion engine, have been required to operate under the high temperature range of $700^{\circ}C$-$800^{\circ}C$ and high pressured gas with repeated mechanical load for the high performance of engines. For these components, friction welding for bonding of dissimilar steels can be applied for in order to obtain process shortening, production cost reduction and excellent bonding quality. And age hardening recently has been noticed to the heat resisting materials for further strengthening of high temperature strength, especially high temperature fatigue strength. However, it is difficult to find out any report concerning the effects of age hardening for strengthening high temperature fatigue strength to the Friction welded heat resisting and anti-corrosive materials. In this study the experiment was carried out as the high temperature rotary bending fatigue testing under the condition of $700^{\circ}C$ high temperature to the friction welded domestic heat resisting steels, SUH3-SUS303, which were 10hr., 100hr. aging heat treated at $700^{\circ}C$ after solution treatment 1hr. at $1, 060^{\circ}C$ for the purpose of observing the effects of the high temperature fatigue strength and fatigue fracture behaviors as well as with various mechanical properties of welded joints. The results obtained are summarized as follows: 1) Through mechanical tests and micro-structural examinations, the determined optimum welding conditions, rotating speed 2420 rpm, heating pressure 8kg/mm super(2), upsetting pressure 22kg/mm super(2), the amount of total upset 7mm (heating time 3 sec and upsetting time 2 sec) were satisfied. 2) The solution treated material SUH 3, SUS 303, have the highest inclination gradient on S-N curve due to the high temperature fatigue testing for long time at $700^{\circ}C$. 3) The optimum aging time of friction welded SUH3-SUS 303, has been recognized near the 10hr. at $700^{\circ}C$ after the solution treatment of 1hr. at $1, 060^{\circ}C$. 4) The high temperature fatigue limits of aging treated materials were compared with those of raw material according to the extender of aging time, on 10hr. aging, fatigue limits were increased by SUH 3 75.4%, SUS 303 28.5%, friction welded joints SUH 3-SUS 303 44.2% and 100hr. aging the rates were 64.9%, 30.4% and 36.6% respectively. 5) The fatigue fractures occurred at the side of the base matal SUS303 of the friction welded joints SUH 3-SUS 303 and it is difficult to find out fractures at the friction welding interfaces. 6) The cracking mode of SUS 303, SUH 3-303 is intergranular in any case, but SUH 3 is fractured by transgranular cracking.