• International Journal of Automotive Technology
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• v.4 no.4
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• pp.203-211
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• 2003

This paper describes a method for a falling weight impact test to estimate the impact energy absorbing characteristics and impact strength of CFRP (Carbon-fiber reinforced plastics) laminate plates based on considerations of stress wave propagation theory, which were converted to measurements of load and displacement verses time. The delamination area of impacted specimens for the different ply orientations was measured with an ultrasonic C-scanner to determine the correlation between impact energy and delamination area. The energy absorbed by a quasi-isotropic specimen having four interfaces was higher than that of orthotropic laminates with two interfaces. The more interfaces, the greater the energy absorbed. The absorbed energy of a hybrid specimen embedding GFRP (Glass-fiber reinforced plastics) layer was higher than that of normal specimens. Also, a falling weight impact tester was built to evaluate the characteristics and impact strength of CFRPs.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.537-538
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• 2007

• Journal of Korean Association for Spatial Structures
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• v.18 no.3
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• pp.19-26
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• 2018

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.969-970
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• 2008

• Proceedings of the Korean Society of Laser Processing Conference
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• 2006.11a
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• pp.17-20
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• 2006

In the remote welding system using $CO_2$ laser, laser beam is rapidly deflected by moving mirrors of scanner system and has focusable distance over 1000mm from workpiece. From such arrangement, various advantages and disadvantages arise. Remote welding is a highly efficient laser process. As the mirrors of the scanner system allow positioning speeds exceeding 700m/s, it becomes possible to reduce the welding cycle time. On the other hand, as there no the provision of shielding gas which is normally required for beam powers exceeding 3kW, may become difficult task. Therefore, In this study, the influence of the various penetration of back bead by the different laser welding speed on the weld seam formation without shielding gas was investigated.

• Korean Journal of Food Science and Technology
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• v.24 no.1
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• pp.42-48
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• 1992

The rate and extent of coagulation of milk using fast acidification with 0.1 N HCl were monitored by changes in viscosity and turbidity at various temperatures and pH. Also the gelation rate of milk using slow acidification with D-glucono-${\delta}$-lactone was measured in a small strain rheological scanner. Coagulation of milk casein occurred in a specific pH range and was accompanied by an abrupt increase in viscosity at pH 5.0. Acid coagulation rate was enhanced by increasing temperature from $20^{\circ}C{\sim}50^{\circ}C$, and the maximum rate was shown around pH 5.0. The addition of salt ($CaCl_{2}$) reduced the maximum coagulation rate at all temperature ranges and shifted the pH ranges for maximum coagulation rate and the onset pH of coagulation. The onset of gelation and the rate of network formation during slow acidification were facilitated by Cl ion, but suppressed by SCN-ion, as indicated by the rate of rigidity development. The susceptibility to syneresis was greater in the gel made at lower temperature and around pH 4.6, while preheated milk at $90^{\circ}C$ for 5 min prior to acidification showed the same syneresis profile at all heating temperatures ($60{\sim}90^{\circ}C$).

• Journal of Biosystems Engineering
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• v.36 no.2
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• pp.96-108
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• 2011

Several methods of in-field measurements of Nitrogen and other soil properties using cores extracted by a hydraulic soil sampler were evaluated. A prototype core scanner was built to accommodate Veris Technologies commercial Vis-NIRS equipment. The testing result for pH, P and Mg were close to RPD (Ratio of Prediction to Deviation = Standard deviation/RMSE) of 2, however the scanner could not achieve the goal of RPD of 2 on some other properties, especially on nitrate nitrogen ($NO_3$) and potassium (K). In situ NIRS/EC probe showed similar results to the core scanner; pH, P and Mg were close to RPD of 2, while $NO_3$ and K were RPD of 1.5 and 1.2, respectively. Correlations between estimations using the probe and the core scanner were strong, with $r^2$ > 0.7 for P, Mg, Total N, Total C and CEC. Preliminary results for mid-IR spectroscopy showed an $r^2$ of 0.068 and an RMSE for nitrate (N) of 18 ppm, even after the removal of calcareous samples and possible N outlier. After removal of calcareous samples on a larger sample set, results improved considerably with an $r^2$ of 0.64 and RMSE of 6 ppm. However, this was only possible after carbonate samples were detected and eliminated, which would not be feasible under in-field measurements. Testing of $NO_3$ and K ion-selective electrodes (ISEs) revealed promising results, with acceptable errors measuring soil solutions containing nitrate and potassium levels that are typical of production agriculture fields.

• The Journal of the Korea Contents Association
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• v.10 no.3
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• pp.101-112
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• 2010

The recent trend of the hacking deals with all the IT infrastructure related to the profit of the companies. Presently, they attack the service itself, the source of the profit, while they tried to access to the service infrastructure through the non-service port in the past. Although they affect the service directly, it is difficult to block them with the old security solution or the old system and they threaten more and more companies with the demand of money menacing the protection of customers and the sustainable management. This paper aims to design and implement multi-platform network packet scanner targeting the exception handling network intrusion detection system which determines normal, abnormal by traffic. Linux and unix have the various network intrusion detection and packet management tools like ngrep, snort, TCPdump, but most of them are based on CUI (Character based User Interface) giving users discomfort who are not used to it. The proposed system is implemented based on GUI(Graphical User Interface) to support the intuitive and easy-to-use interface to users, and using Qt(c++) language that supports multi-platform to run on any operating system.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.2
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• pp.167-184
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• 1999

The purpose of this study was to evaluate and compare the at of denture bases processed by injection pressing technic using laser scanner of reverse engineering technic. The auther duplicated 20 maxillary edentulous models and 20 mandibular edentulous models, which were scanned on HYSCAN 45C 3D BCANNER(Hymarc Co., Canada). The scanned data were stored in the personal computer using SURFACER (Imageware Co. U.S.A.) software program. After 40 dentures were cured by PERform Inkovac system, SR-Ivocap system, Palajet system, and Sulfon system, they were stored in water at room temperature fir 24 hours. The dentures were scanned on HYSCAN 45C 3D SCANNER(Hymarc Co., Canada). The scanned data were stored in the personal computer using SURFACER (Imageware Co., U.S.A.) software program. By overlapping two images using the same program, the fit between two surfaces was scaled by positive and negative errors. The obtained results were as follows 1. In the upper denture, most of the positive errors occurred on the lingual side of anterior alveolar ridge and the negative errors were on the flange of denture bases. 2. In the lower denture, most of the positive errors occurred on the inner side of lingual flange and the negative errors were on the border of anterior labial flange areas, 3. There were no statistical differences among the positive errors of the four types of injection denture curing methods and also no statistical differences between negative errors except only in negative maximum errors. 4. In PERform system and SR-Ivocap system, they have the tendency of inaccurate at of lower denture bases comparing to that of upper denture bases. 5. The negative error scales were greater than the positive error scales in all types of injection denture curing methods.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.385-386
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• 2012