• Journal of The Korean Society of Grassland and Forage Science
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• v.23 no.3
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• pp.151-158
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• 2003

This study was carried out to determine the effect of pig slurry applications on the forage yield of Sorghum${\times}$Sudangrass hybrid and leaching of $NO_3$-N in volcanic ash soil in Jeju. It was arranged as a randomized block design with seven treatments: chemical fertilizer ($N-P_2$$O_{5}$ $-K_2$O=200-l50-150kg/ha), pig slurry 200kg N/ha, pig slurry 300kg N/ha, pig slurry 400kg N/ha, pig slurry 100kg N/ha+chemical fertilizer 100kg N/ha, pig slurry 150kg N/ha+chemical fertilizer 100kg N/ha, pig slurry 200kg N/ha+chemical fertilizer 100kg N/ha. The mean dry matter yield of Sorghum${\times}$Sudan grass hybrid per ha for 4 years(1998 to 2001) was higher(p<0.05) in pig slurry 300kg N/ha(l7,279kg) and pig slurry 400kg N/ha(17,817kg) treatments than those of other treatments. The $NO_3$-N concentrations of leaching water at soil depth 30cm in all treatments were excess the standard of WHO with level of $10.0mg/\ell$ on 20 days of the seeding, but this $NO_3$-N concentrations found to be below $5.0mg/\ell$ on August.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.3
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• pp.243-250
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• 2011

This experiment was conducted to evaluate agronomic characteristics, forage quality and dry matter (DM) yield of early-maturing hairy vetch 'Cold green', 'Haymaker plus', 'Cappello' and medium-late maturing cultivar 'Cheong pa', 'Challenger', 'Hungvillosa' and 'Latigo' at Seongju in the Kyeongbuk from 2009 to 2011. The experiment was arranged in randomized complete block design with three replications. Hairy vetchs were seeded on Sep. 26 and Oct. 11 in 2009 and 2010. Vetch plants were harvested on 30 Apr. in 2010 and 2011. Cold tolerance for Haymaker plus and Cappello were a little lower than other cultivars. Fifty percent-flowering dates of Cold green had earlier than others and Haymaker plus and Cappello were earlier than Cheong pa, Challenger, Hungvillosa and Latigo. Cheong pa and Challenger were ealirer than Hungvillosa and Latigo. The DM yield of Cold green was the highest (p<0.05) of the cultivar except Haymaker plus. Haymaker plus was higher (p<0.05) than others and Cappello, Cheong pa, Challenger were higher (p<0.05) than Hungvillosa and Latigo in 2010. In 2011, the DM yield of Cold green was the highest (p<0.05) of the cultivar and Haymaker plus was higher (p<0.05) than others. Cappello was higher (p<0.05) than Hungvillosa and Latigo. Cheong pa and Challenger were higher (p<0.05) than Latigo. Vetch cultivar was high in crude protein (CP) and low in Acid detergent fiber (ADF). According to the results obtained from this study, it is suggested that early-maturing cultivar would be recommendable for fall sown vetch for DM production.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.27 no.4
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• pp.247-254
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• 1991

Mackerel purse seine fishery is one of the most important fisheries in Korea and its annual mean catch from 1982 to 1988 is 350 thousand tons. Between 1982 and 1988, the characteristics of catch at 5 sectors of the sea area was analyzed according to operating sea block and the catch by fishes based on the data obtained from daily report of fishing condition that had been made out by 48 Korean fishing boats engaged in the fishery of purse seine. In these 5 sectors of the sea area, catch per net hauling in the coastal area of Cheju Island is less than that in the other sectors. Accordingly, the shape of fishing gear during operation has been measured to analyzed the deformation of net shape caused by the bottom current. (The lunar calender is used in the paper) The results obtained are as follows; The average CPUE of purse seines is 31.6 tons and it is higher from October to April than that from May to September. In the 5 purse seine fishing grounds, the ratio of net haul in the coastal sea area of cheju Island is 42.4% and it is the highest level, but the CPUE is 25.7 tons which is relatively low level. Each CPUE in the sea areas is significant differences with 1% level. Index of seasonal variation of mackerel CPUE from May to October is lower than the standard value, whereas index from November to January is higher. The diameter of circle by net shooting becomes shorter to the minimum caused by the bottom current during loose set, becomes narrower and the efficiency of fish encirclement becomes lower. The shape of leadline by bottom current becomes long oval type along with current direction in the tight set, while it becomes long oval type in the direction of a right angle to the current direction and the enclosed area is reduced hurriedly, and the deformation of net is most serious in the loose set.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.732-742
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• 2016

This study suggests methods of defense against low-level high-bandwidth DDoS attacks by adding a solution with a time limit factor (TLF) to an existing high-bandwidth DDoS defense system. Low-level DDoS attacks cause faults to the service requests of normal users by acting as a normal service connection and continuously positioning the connected session. Considering this, the proposed method makes it possible for users to show a down-related session by considering it as a low-level DDoS attack if the abnormal flow is detected after checking the amount of traffic. However, the service might be blocked when misjudging a low-level DDoS attack in the case of a communication fault resulting from a network fault, even with a normal connection status. Thus, we made it possible to reaccess the related information through a certain period of blocking instead of a drop through blacklist. In a test of the system, it was unable to block the session because it recognized sessions that are simply connected with a low-level DDoS attack as a normal communication.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.9-12
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• 2016

The process parameters of DC pulsed sputtering to produce a multi-layer thin film with light reflectance at a specific wavelength region were studied. The optical simulation of multi-layer thin films of the silicon dioxide ($SiO_2$) films with a low refractive index and the titanium dioxide ($TiO_2$) films with a high refractive index was done. Under a DC pulsed sputtering power of 2kW and 200 sccm(standard cubic centimeter per minute) argon gas, the silicon dioxide films with a refractive index of 1.46 in the range of oxygen gas ratios of 12% and a titanium dioxide film with a refractive index of 2.27 in the range of oxygen gas ratios of 1% were produced. The multi-layer structure of high refractive index/low refractive index/high refractive index was designed and fabricated. The characteristics of the fabricated multi-layer thin film structure showed a reflectance of more than 45% in the range, 780 to 1200nm. This multi-layer structure is expected to be used to block the near infrared wavelength light.

• Restorative Dentistry and Endodontics
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• v.35 no.6
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• pp.461-472
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• 2010

Objectives: This study evaluated microtensile bond strength (${\mu}TBS$) and short-rod fracture toughness to explain fractural behavior of repaired composite restorations according to different surface treatments. Materials and Methods: Thirty composite blocks for ${\mu}TBS$ test and sixty short-rod specimens for fracture toughness test were fabricated and were allocated to 3 groups according to the combination of surface treatment (none-treated, sand blasting, bur roughening). Each group was repaired immediately and 2 weeks later. Twenty-four hours later from repair, ${\mu}TBS$ and fracture toughness test were conducted. Mean values analyzed with two-way ANOVA / Tukey's B test ($\alpha$= 0.05) and correlation analysis was done between ${\mu}TBS$ and fracture toughness. FE-SEM was employed on fractured surface to examine the crack propagation. Results: The fresh composite resin showed higher ${\mu}TBS$ than the aged composite resin (p < 0.001). Mechanically treated groups showed higher bond strength than non-mechanically treated groups except none-treated fresh group in ${\mu}TBS$ (p < 0.05). The fracture toughness value of mechanically treated surface was higher than that of non-mechanically treated surface (p < 0.05). There was no correlation between fracture toughness and microtensile bond strength values. Specimens having high KIC showed toughening mechanism including crack deviation, microcracks and crack bridging in FE-SEM. Conclusions: Surface treatment by mechanical interlock is more important for effective composite repair, and the fracture toughness test could be used as an appropriate tool to examine the fractural behavior of the repaired composite with microtensile bond strength.

• Journal of Korean Neurosurgical Society
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• v.60 no.5
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• pp.498-503
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• 2017

Objective : The purpose of the present study was to compare inter-fragmentary compression pressures after fixation of a simulated type II odontoid fracture with the headless compression Herbert screw and a half threaded cannulated lag screw. Methods : We compared inter-fragmentary compression pressures between 40- and 45-mm long 4.5-mm Herbert screws (n=8 and n=9, respectively) and 40- and 45-mm long 4.0-mm cannulated lag screws (n=7 and n=10, respectively) after insertion into rigid polyurethane foam test blocks (Sawbones, Vashon, WA, USA). A washer load cell was placed between the two segments of test blocks to measure the compression force. Because the total length of each foam block was 42 mm, the 40-mm screws were embedded in the cancellous foam, while the 45-mm screws penetrated the denser cortical foam at the bottom. This enabled us to compare inter-fragmentary compression pressures as they are affected by the penetration of the apical dens tip by the screws. Results : The mean compression pressures of the 40- and 45-mm long cannulated lag screws were $50.48{\pm}1.20N$ and $53.88{\pm}1.02N$, respectively, which was not statistically significant (p=0.0551). The mean compression pressures of the 40-mm long Herbert screw was $52.82{\pm}2.17N$, and was not statistically significant compared with the 40-mm long cannulated lag screw (p=0.3679). However, 45-mm Herbert screw had significantly higher mean compression pressure ($60.68{\pm}2.03N$) than both the 45-mm cannulated lag screw and the 40-mm Herbert screw (p=0.0049 and p=0.0246, respectively). Conclusion : Our results showed that inter-fragmentary compression pressures of the Herbert screw were significantly increased when the screw tip penetrated the opposite dens cortical foam. This can support the generally recommended surgical technique that, in order to facilitate maximal reduction of the fracture gap using anterior odontoid screws, it is essential to penetrate the apical dens tip with the screw.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.10
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• pp.713-722
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• 2013

This paper proposes a method of using depth information to detect the hand region in real-time based on the cascade method. In order to ensure stable and speedy detection of the hand region even under conditions of lighting changes in the test environment, this study uses only features based on depth information, and proposes a method of detecting the hand region by means of a classifier that uses boosting and cascading methods. First, in order to extract features using only depth information, we calculate the difference between the depth value at the center of the input image and the average of depth value within the segmented block, and to ensure that hand regions of all sizes will be detected, we use the central depth value and the second order linear model to predict the size of the hand region. The cascade method is applied to implement training and recognition by extracting features from the hand region. The classifier proposed in this paper maintains accuracy and enhances speed by composing each stage into a single weak classifier and obtaining the threshold value that satisfies the detection rate while exhibiting the lowest error rate to perform over-fitting training. The trained classifier is used to classify the hand region, and detects the final hand region in the final merger stage. Lastly, to verify performance, we perform quantitative and qualitative comparative analyses with various conventional AdaBoost algorithms to confirm the efficiency of the hand region detection algorithm proposed in this paper.

• Journal of the Korean GEO-environmental Society
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• v.16 no.7
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• pp.35-42
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• 2015

Grouting method has been widely used for the ground improvement and stabilization: mostly to block or control the ground water in the early years and to improve the ground, repair the structure in recent years, ever increasing its use. Despite many advantages so far, the existing grouting method also has some shortcomings including uncertain permeation of grouting with gravity type if the voids between the soil particles are narrow, and problems due to the relaxation of the neighboring ground when injected using injection pressure. As an alternative, a vibration injection method with constant amplitude and frequency has been developed in recent years, with the vibration grouting being reported to have a permeability increasing effect of grout material compared with the positive pressure injection type. Accordingly, the purpose of this study is to investigate the improvement effect of the vibration grouting that applies short-period vibration energy by varying vibration cycle, vibration time and ground conditions to evaluate the strength enhancing effect of grouting materials, expansion effect of grouting body, ground improvement effect of the grouting and the penetration characteristics of the rock joint. The findings of this study show the improved compressive strength of grout, expansion of grouting body and increased penetration rate, according to the vibration compared with non-vibration under the loose soil condition.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.6
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• pp.123-132
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• 2012

Gas sensors has been used very differently that depending on following purposes; Automotive (exhaust gas, fuel mixture gas, oxygen, particulates), agriculture / food industry (fresh, stored, CO2, humidity, NH3, nitrogen oxide gas, organic gas, toxic gas emitted from pesticides and insecticides), industrial / medical (chemical gas, hydrogen, oxygen and toxic gases), military (chemical weapon), environmental measurements (CO and other air pollution consisting of sulfur and nitrogen gas), residential (LNG, LPG, butane, indoor air, humidity). The types of industrial toxic substances are known about 700 species and many of these exist in gaseous form under normal conditions. he multi-gas detection sensors will be developed for casualties that detect the most important and find easy three kinds of gases in marine plant; carbon dioxide(CO2), carbon(CO), ammonia(NH3). Package block consists of gas sensing device minor ingredient, rf front end, zigbee chip. Develope interworking technology between the sensor and zigbee chip inside a package. Conduct a performance test through test jig about prototype zigbee sensor module with rf output power and unwanted emission test. This research task available early address when poisonous gas leaked from large industrial site and contribution for workers' safety at the enclosed space.