• The KIPS Transactions:PartC
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• v.14C no.1 s.111
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• pp.65-72
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• 2007

The existing RBAC models are not sufficient for managing delegations or separation of roles. Researches have been done on RBDM(Role Based Delegation Model) that deal with delegating role or permission to other users. In this paper, we divide the delegated roles into two groups: periodic and temporary delegation roles. When a role is delegated, a time period is assigned together, which is used to revoke the permission of delegated role automatically. In our model, the role of monotonic delegation by an original user can be revoked at any time in case of malicious use by the delegated user. The contribution of our model is that the malicious use of delegated role can be prohibited and security vulnerability in the role hierarchy due to role delegations can be alleviated. The proposed model, T RBDM(Time out Based RBDM) is analyzed and compared with the conventional models, such as RBDM0, RBDM1 and PBDM. Our model shows an advantage over other models in terms of security robustness.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.7
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• pp.130-136
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• 2002

In this paper, a flight test method is described for the system identification of the unmanned aerial vehicle equipped with an automatic flight control system. Multistep inputs are applied for both longitudinal mode and lateral/directional excitation. Optimal time step for excitation is sought to provide the broad input bandwidth. A programmed mode flight test method provides high-quality flight data for system identification using the flight control computer with the longitudinal and lateral/directional autopilot which enables the separation of each motion during the flight test. In addition, exact actuating input that is almost equivalent to the designed one guarantees the highest input frequency attainable. Several repetitive flight tests were implemented in the calm air in order to extract the consistent system model for the air vehicle. The enhanced airborne data acquisition system endowed the high-quality flight data for the system identification. The flight data were effectively used to the system identification of the unmanned aerial vehicle.

• Korean Journal of Pharmacognosy
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• v.43 no.2
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• pp.137-146
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• 2012

Dipsaci Radix (Dipsacaceae) has been used as a tonic, an analgesic, anti-inflammatory and anti-complement agents in traditional herbal medicine for the therapy of low back pain, knee pain, rheumatic arthritis, traumatic hematoma, and bone fractures. A high-performance liquid chromatography-electrospray ionization-mass spectrometric method (HPLC-ESI-MS) was developed for the simultaneous quantitation method of the five compounds from the herbal drug: asperosaponin VI and asperosaponin XII (terpene glycosides), sweroside, loganin and dipsacus A(iridoid glycosides). HPLC separation of the analytes was achieved on a C18 column ($150{\times}2.0$ mm i.d., 5 ${\mu}m$) using the aqueous methanol containing 5 mM ammonium acetate with gradient flow of the mobile phase. Detection of the analytes was performed by positive ion electrospray ionization, and selected ion monitoring was used for data acquisition using m/z corresponding molecular adduct ion, $[M+NH_4]^+$ and $[M+H]^+$. Calibration graphs showed good linearity ($r^2$=0.9997) over the wide range of the analytes; intra- and inter-day precisions (RSD, %) were within 9.1% and the accuracy between 94.0-111.0%. Recoveries of the analytes through the assay procedure were in the range of 93.7-110.8%. Analytical results of the herbal drugs of Dipsaci Radix (17 samples) show wide distribution of the five marker compounds and clear difference of the species from Phlomidis Radix (4 samples). The developed method would provide a practical guide for the quality control of the herbal drug.

• The Journal of the Acoustical Society of Korea
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• v.33 no.6
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• pp.375-382
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• 2014

In many practical active noise control applications, the primary noise contains multiple closely-spaced harmonics. A narrowband ANC system consists of adaptive filters excited by a composite reference signal, which is the set or sum of sinusoids. This paper analyzes and shows that the convergence speeds of the direct form, parallel form, and simplified parallel form narrowband ANC systems are affected by the fundamental frequency and frequency separation between two adjacent sinusoids in the reference signal. This paper also proposes the new simplified parallel form narrowband ANC system whose convergence speed is independent on the frequency of the reference signal. Computer simulations are conducted to verify the analysis presented in the paper and to compare the proposed narrowband ANC system with the conventional narrowband ANC system.

• Korean Journal of Food Science and Technology
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• v.28 no.6
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• pp.1009-1013
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• 1996

This study was carried to investigate the emulsion stability of microcrystalline chitins (MCC) prepared from chitins of different molecular sizes and different degrees of phosphorylation in a model fatty food system. Chitins of low, medium and high molecular size prepared from crabshells were phosphorylated to 30-50% to make MCC. MCC prepared from chitin of medium molecular size revealed a high emulsion stability. The best emulsion stability was observed in MCC prepared from medium size chitin with 40% phosphorylation (M-40-MCC). The fat binding capacity of MCC was not significantly different among the samples. MCC with 50% phosphorylation had more fat binding capacity, ranging from 650-690%. When 2.46% of M-40-MCC was applied to a coconutoil-water system as an emulsifier, emulsion separation was observed from 10 min after emulsification, indicating that it could not be used as a sole emulsifier. When 50% of emulsifier (Span-60 &Tween-60) in a liquid coffee creamer, selected as a model fatty foods, was replaced by M-40-MCC, emulsion stability was as good as control. Consistency of liquid creamer was decreased and L value increased as the amount of MCC repacement increased. A liquid creamer with 50% emulsifier replaced by MCC had sensory characteristics equivalent to control.

• Restorative Dentistry and Endodontics
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• v.25 no.3
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• pp.371-380
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• 2000

The effect of fiber reinforcing materials on the fracture strength of composite resin was evaluated. Each ten composite resin bars reinforced by glassfiber[Fiber-Splint ML$^{(R)}$(Polydentia SA, Switzerland)], polyethylene fiber [Ribbond$^{(R)}$(Ribbond Inc., U.S.A.)] and polyaramid fiber[Kevlar$^{(R)}$(DuPont, U.S.A.)] were loaded under the 3-point compression technique. Another ten pure composite resin bars without reinforcement were used as a control group. Then mean fracture strength and standard deviation were calculated and a ANOVA and Scheffe test were used in statistics. The results were as follows: 1. Kevlar group showed the highest fracture strength as 175.5MPa (p<0.05). Fiber-Splint ML group showed the lowest fracture strength as 112.7MPa. 2. The mean value of fracture strength in Ribbond group was 136.4MPa, and that of unterated control group was 143.6MPa. No difference was found between the two groups. 3. Ribbond and Kevlar reinforcement groups showed a catastrophic failure, where complete separation of pieces occurs to a unseparated fracture pattern. The use of Kevlar reinforcement fibers with composite resin showed significant increase in the average load failure and the presence of the fibers did prevent the catastrophic crack propagation present in the unreinforced samples. The use of Ribbond reinforcement fibers with composite resin showed no significant increase in the average load failure. However, the presence of the fibers did prevent the catastrophic crack propagation. Because high strength of glassfiber are rapidly degraded on exposure to moisture and humidity. The use of Fiber-Splint ML reinforcement fibers with composite resin showed significant decrease in the average load failure and displayed catastrophic fractures.

• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.2
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• pp.46-52
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• 2006

Techniques used for thrust vector control in rocket motors are mainly classified nozzles installed mechanical interference on the expansive region of nozzle(such as jet tabs and jet vanes) and movable nozzles(such as ball&socket and flexible seal). Using the numerical analysis and cold-flow test, this paper evaluates the performance of supersonic nozzle with asymmetric entrance shape when the test nozzle, especially ball&socket, is tilted. Numerical result shows that the effect of the asymmetric entrance shape on the flow field is suddenly diminished at the nozzle throat and downstream is mostly free from the effect of asymmetric entrance shape. Although the calculated thrust and lateral force are less than those of cold-flow test, two results show a fairly good agreement. But the cold-flow test results indicate the effective angles calculated from measured forces are not agreement with the geometric angles.

• Journal of Radiation Protection and Research
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• v.41 no.3
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• pp.253-259
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• 2016

Background: This study investigated the effects of zoledronic acid (ZA) on radiation-induced bone loss in C3H/HeN mice. Materials and Methods: C3H/HeN mice were divided into sham control and three irradiated groups (3 Gy, gamma ray). The irradiated mice were treated for 12 weeks with vehicle, amifostine (intraperitoneal injection), or ZA (subcutaneous injection). Grip strength, uterus weight, and serum alkaline phosphatase (ALP), and tartrate-resistant acid phosphatase (TRAP) levels were measured. Tibiae were analyzed using micro-computed tomography. Results and Discussion: Treatment of ZA ($100{\mu}g{\cdot}kg^{-1}{\cdot}week^{-1}$) significantly preserved trabecular bone volume, trabecular thickness, trabecular number, trabecular separation, bone mineral density of proximal tibia metaphysic, and cortical bone volume, but did not alter the uterus weight of the mice. The administration of ZA for 12 weeks lowered serum ALP and TRAP levels in irradiated mice, suggesting that ZA can reduce the bone turnover rate in mice. No differences were apparent between the amifostine-treated group and the irradiation control group. Conclusion: The results indicate that ZA can prevent radiation-induced bone loss in mice.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.3
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• pp.703-713
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• 2015

The linking system between the control system and the field devices in the existing EMS/SCADA, in order to increase the reliability of the data, and access control through the separation of external network. Currently, There is a tendency that the need for connection to an external network that takes into account the economic aspect, systematic management and efficiency of operations is increasing. Such is evolved linkage section, is to have more security vulnerabilities than in the past, Eventually communication EMS/SCADA linkage section requires special management method. In this paper, taking into account the domestic environment, were presented the security Certification and Accreditation technology that was applied to serial DNP3 and TCP/IP based DNP3 that are mainly used in EMS/SCADA linkage section. Presented to security of Certification and Accreditation technology, divided into Resource Robustness Test and Malicious Packet Test for evaluate the safety. Each of the security requirements and evaluation method in proposed technology, is an attempt to present the differentiation of the existing Certification and Accreditation technology.

• Korean Journal of Oriental Medicine
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• v.15 no.2
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• pp.119-124
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• 2009

The purpose of this study was investigation of quantitative analysis of marker substances in Paeonia lactiflora extracts by solid fermentation. High performance liquid chromatography (HPLC) for the determination of albiflorin and paeoniflorin in P. lactiflora extracts by solid fermentation, the separation method was performed on C18 column ($250\;mm\;{\times}\;4.6\;mm$, $5\;{\mu}m$, RS tech) using gradient solvent mixtures of water-acetonitrile with photodiode array detector (230nm). The flow rate was 1.0 ml/min. Retention time of albiflorin and paeoniflorin was about 28.88, 31.92 min and linearity of calibration was showed good result(r2 = 0.9998, 0.9996), respectively. Content of albiflorin was $0.090\;{\pm}\;0.03%$ in P. lactiflora extract(control), $0.102\;{\pm}\;0.00%$ in P. lactiflora extract fermented with Paecilomyces japonica, $0.056\;{\pm}\;0.01%$ in P. lactiflora extract fermented with Ganoderma lucidum, $0.093\;{\pm}\;0.00%$ in P. lactiflora extract fermented with honey and $0.046\;{\pm}\;0.00%$ in P. lactiflora extract fermented with Nuruk. Content of paeoniflorin was $4.506\;{\pm}\;0.13%$ in control, $2.599\;{\pm}\;0.04%$ in P. lactiflora extract fermented with Paecilomyces japonica, $1.222\;{\pm}\;0.03%$ in P. lactiflora extract fermented with Ganoderma lucidum, $2.750\;{\pm}\;0.05%$ in P. lactiflora extract fermented with honey and $0.847\;{\pm}\;0.00%$ in P. lactiflora extract fermented with Nuruk, respectively. Content of the marker substances did not increase in all fermentation experiment group.