• The KIPS Transactions:PartC
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• v.11C no.6 s.95
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• pp.725-730
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• 2004

Separation of Duty(SOD), with delegation, is one of important security principles in access control area. The role-based access control model adopts SOD principle, but it has some problems; SOD concept is inconsistent with role hierarchy, permissions that have no relation with SOD may be restricted, and delegation may violate SOD. We propose permission-based SOD model on role-based access control. We establishes SOD as a set of permissions instead of role level SOD. Furthermore we propose a principle of role activation. It solves SOD problems of RBAC and supports easy implementation of SOD policy.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1360-1364
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• 2004

This paper propose an extended model for role-permission assignment based on locations called "Enhanced Role-Based Access Control (ERBAC03)". The proposed model is built upon the well-known RBAC model. Assigning permissions to role is considered too complex activity to accomplish directly. Instead we advocate breaking down this process into a number of steps. The concept of jobs and tasks is specifically introduced to facilitate role-permission assignment into a series of smaller steps. This model is suitable for any large organization that has many branches. Each branch consists of many users who work in difference roles. An administration tool has been developed to assist administrators with the administration of separation of duty requirements. It demonstrates how the specification of static requirements can be done based on "conflicting entities" paradigm. Static separation of duty requirements must be enforced in the administration environment. Finally, we illustrate how the ERBAC03 prototype is used to administer the separation of duty requirements.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.12
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• pp.1059-1066
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• 2007

An experimental study has been conducted to investigate the flow separation control effects of a blowing jet on an elliptic airfoil at a Reynolds number of 7.84×105 based on the chord length. A blowing jet was obtained by pressing a plenum inside the airfoil and ejecting flow out of a thin jet slot that located in leading edge or trailing edge. The experimental results have shown that the blowing jet had an effect of suppressing the flow separation, resulting in the higher suction pressure distribution and higher normal force. The increase in Cn was more pronounced at higher incidence, whereas the effectiveness of the blowing jet reduced at lower incidences. The leading edge pulsating blowing with 90° was the most effective in controlling the flow separation than other types of blowing jet configuration tested in this research. Moreover, when the pulsating blowing was applied, the stall angle was postponed about 2°-3°. The continuous and pulsating blowing jet is a direct and effective flow separation control for improving the aerodynamic characteristics and performances of airfoil.

• Journal of Korean Society of Transportation
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• v.12 no.3
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• pp.15-27
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• 1994

A mathematical model and its solution algorithm are proposed for computing the capacity of terminal control area. The model is built based on dynamics of aircraft flying on pre-established approach path and its solution algorithm employs a numerical method. The model computes the minimum separation of two aircraft at the entry fix of the terminal control area, which assures that air traffic separation rules are not violated during the approach phase, thereby computes the capacity. The model might be applied for designing approach paths for a new airport, for rearranging paths of an existing airport or establishing approach control procedures.

• YAKHAK HOEJI
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• v.41 no.5
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• pp.539-546
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• 1997

Capillary electrophoresis (CE) is perceived as an attractive tool for the analysis of pharmaceuticals and biological materials because of their high separation efficiency, easy separation and low running cost. New concept of micellar electrokinetic capillary chromatography (MECC) expanded the application of CE to the separation of neutral molecules. Validation of CE as an analytical technique for quality control of pharmaceuticals should be confirmed by quantitative analysis and the peak confirmation. In this study, the quantitative analyses of various types of neutral, acidic and basic components (acetaminophen, caffeine, ascorbic acid, riboflavin, thiamine, chlorpheniramine, phenylpropanolamine, dl-methylephedrine and dextromethorphan) in complex cold medicines have been accomplished using CE. Combined methods of MECC using SDS and capillary zone electrophoresis lowering the pH of running buffer were adopted to determine the ingredients in capsule type or liquid formula complex medicines without particular sample pretreatment. The results indicate that CE is a promising technique for quality control analysis of pharmaceuticals as a validation method.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2868-2872
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• 2007

In this study, a passive control using a boat-tail device is conducted for a three-dimensional car model in ground proximity. We consider various boat-tails and investigate the mechanism of drag reduction by them. By varying the length and slant angle of boat-tail, we obtain drag reductions up to 40%. From the oil-surface flow visualization and hot-wire measurement, the drag reduction by the boat-tail is characterized by the shear-layer instability and reattachment on the boat-tail, forming a small separation bubble at the upstream part of boat-tail surface, resulting in the delay of main separation and drag reduction. At high slant angles, the flow fully separates and drag is nearly same as that of no control.

• Progress in Superconductivity and Cryogenics
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• v.14 no.4
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• pp.1-4
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• 2012

The applicability of the two types of magnetic separation system, high gradient magnetic separation (HGMS) and Magneto Archimedes method were studied considering the magnetic susceptibility of targeted substances. It was noted that the combination of the two methods can control the almost all the substances, paramagnetic and diamagnetic in addition to ferromagnetic substances. The principle of the methods was given and the conceput of the magnet force control technology is discussed. The practical applications of the technique were introduced together with the new application of HGMS.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1350-1354
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• 2004

This paper proposes a simple but practically useful model for preventing fraud of users called "ERBAC03". The new model consists of qualified mandatory and discretionary features for roles and locations, including the assignment of permissions for the appropriate roles and the assignment of roles for the appropriate locations. Moreover, a static separation of duty (SSoD) principle is applied to the new model for integrity requirements of security systems. The paper also explores some extensions of ERBAC03 including the new model using the SSoD concept from some experiments. The experimental results prove the efficiency improvement of the proposed model that can make benefits for large enterprises.

• Journal of Korea Society of Digital Industry and Information Management
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• v.15 no.3
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• pp.101-109
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• 2019

In addition to enabling access, database accounts play a protective role by defending the database from external attacks. However, because only a single account is used in the database, the account becomes the subject of vulnerability attacks. This common practice is due to the lack of database support, large numbers of users, and row-based database permissions. Therefore if the logic of the application is wrong or vulnerable, there is a risk of exposing the entire database. In this paper, we propose a Least-Privilege Account Separation Model (LPASM) that serves as an information guardian to protect the database from attacks. We separate database accounts depending on the role of application services. This model can protect the database from malicious attacks and prevent damage caused by privilege escalation by an attacker. We classify the account control policies into four categories and propose detailed roles and operating plans for each account.

• Journal of computational fluids engineering
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• v.15 no.4
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• pp.46-52
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• 2010

In the present work, the aerodynamic characteristics of elliptic airfoils which have a 12% thickness ratio are numerically investigated based on Reynolds-averaged Navier-Stokes equations and a transition SST model at a Reynolds number 8.0$\times$105. The numerical simulation of a synthetic jet actuator which is a well-known zero-net-mass active flow control actuator located at x/c = 0.00025, was performed to control massive flow separation around the leading edge of the elliptic airfoils. Four cases of non-dimensional frequencies were simulated at an angle of attack of 12 degree. It is found that the size of the vortex induced by synthetic jets was getting smaller as the jet frequency becomes higher. Comparison of the location of synthetic jets between x/c = 0.00025 (around the leading edge) and x/c = 0.9 (near the separation) shows that the control near the leading edge induces closed recirculation flow regions caused by the interaction of the synthetic jet with the external flow, but the control applied at 0.9c (near the trailing edge) induces a very small and weak vortex which quickly decays due to weak intensity.