• The KIPS Transactions:PartC
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• v.15C no.6
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• pp.493-506
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• 2008

In this paper we suggest dynamic access control model based on context satisfied with requirement of u-healthcare environment through researching the role based access control model. For the dynamic security domain management, we used a distributed object group framework and context information for dynamic access control used the constructed database. We defined decision rule by knowledge reduction in decision making table, and applied this rule in our model as a rough set theory. We showed the executed results of context based dynamic security service through u-healthcare application which is based on distributed object group framework. As a result, our dynamic access control model provides an appropriate security service according to security domain, more flexible access control in u-healthcare environment.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.3
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• pp.432-439
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• 2003

Inconel 690 for nuclear steam generator tube has more Chromium than the conventionally used Inconel 600 in order to increase the corrosion resistance. To evaluate the tribological characteristics of Inconel 690 under fretting condition the fretting tests were carried out in air and elevated temperature water. Fretting tests of the cross-cylinder type were done under various vibrating amplitudes and applied normal loads in order to measure the friction forces and wear volumes. From the results of fretting wear tests. the wear of Inconel 690 can be predictable using the work rate model. The amounts of friction forces were proportional to relative movement between two fretting surfaces. The friction coefficients were decreased as increasing the normal loads and deceasing the vibrating amplitudes. Depending on fretting environment, distinctively different wear mechanisms and often drastically different wear rates can occur It was found that the fretting wearfactors in air and water at 2$0^{\circ}C$, 5$0^{\circ}C$, and 8$0^{\circ}C$ were 7.38 $\times$ $10^{-13}$$Pa^{-1}$, 2.12 $\times$$10^{-13}$$Pa^{-1}$, 3.34$\times$$10^{-13}$$Pa^{-1}$and 5.21$\times$$10^{-13}$$Pa^{-1}$, respectively flexibility to model response data with multiple local extreme. In this study, metamodeling techniques are adopted to carry out the shape optimization of a funnel of Cathode Ray Tube, which finds the shape minimizing the local maximum principal stress. Optimum designs using two metamodels are compared and proper metamodel is recommended based on this research.

• The KIPS Transactions:PartC
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• v.12C no.6 s.102
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• pp.817-826
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• 2005

BcN(Broadband convergence Network) is being developed in order to support a variety of network applications, with enhanced capabilities of QoS(Quality of Service) provisioning and security, and IPv6. In a high-speed network environment such as BcN, it if more likely for the network resources to be exposed to various intrusion activities. The propagation speed of intrusion is alto expected to be much faster than in the existing Internet In this paper, we present a multi-domain security management framework which my be used for a global intrusion detection at multiple domains of BcN and describe its characteristics. For the performance evaluation, we first present test results for the security node and compare with other products. Then we design and Implement an OPNET simulator for the proposed framework, and present some simulation results. In the simulation model, we focus on the performance of alert information in the security overlay network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.9
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• pp.811-819
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• 2014

Activity recognition is a key component in identifying the context of a user for providing services based on the application such as medical, entertainment and tactical scenarios. Instead of applying numerous sensor devices, as observed in many previous investigations, we are proposing the use of smartphone with its built-in multimodal sensors as an unobtrusive sensor device for recognition of six physical daily activities. As an improvement to previous works, accelerometer, gyroscope and magnetometer data are fused to recognize activities more reliably. The evaluation indicates that the IBK classifier using window size of 2s with 50% overlapping yields the highest accuracy (i.e., up to 99.33%). To achieve this peak accuracy, simple time-domain and frequency-domain features were extracted from raw sensor data of the smartphone.

• The KIPS Transactions:PartC
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• v.18C no.6
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• pp.389-396
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• 2011

Recently, researches on the shared authentication based on single sign-on have been actively performed so as to solve the problems of current service provider-centric and isolated Internet authentications, including low usability, high cost structure, and difficulty in privacy protection. In order for the shared authentication model, where the authentications of an authentication provider are shared by several Internet service providers, to be accepted in real Internet environment, trustworthiness among users, service providers, and authentication providers on the level of authentication assurance and the level of authentication information protection is necessarily required. This paper proposes a framework for trustworthy and privacy-protected shared authentication protocol based on the user-centric operation and open trust provider network. The proposed framework is differentiated from previous works in the points that it is able to provide interoperable shared authentication services on the basis of open trust infrastructure.

• Journal of the Microelectronics and Packaging Society
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• v.31 no.3
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• pp.99-104
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• 2024

With the advancement of power electronics technology and the increasing demand for high-efficiency power semiconductors, silicon carbide (SiC) devices have gained attention as an alternative to overcome the limitations of traditional silicon (Si) semiconductors. SiC devices enable excellent switching efficiency due to their high switching speed. However, parasitic inductance within the power module can cause voltage oscillations and overshoot phenomena, potentially leading to issues with electrical reliability and efficiency. To address these challenges, two approaches were proposed and validated. The first approach involved applying an RC snubber circuit to mitigate the effects of parasitic inductance, thereby improving electrical stability. The second approach focused on optimizing the lead-frame design to reduce parasitic inductance. Both methods were verified through simulations and experiments, demonstrating that the electrical reliability and efficiency of SiC power modules can be simultaneously improved.

• The KIPS Transactions:PartC
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• v.10C no.3
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• pp.295-304
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• 2003

Currently security researchers focus on protection of program and data from malicious users and accidents. Therefore, many firewalls and intrusion detection systems have been developed commercially. The intrusion tolerance is a new concept that is the last line of defense for the information survivability. It emphasizes availability and integrity to provide critical system services continuously even when system is compromised. In this paper, we classify current intrusion tolerant technologies from the point of view of program and data. Furthermore, we propose an integrated framework that supports intrusion tolerance of program and data.

• The KIPS Transactions:PartC
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• v.10C no.5
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• pp.595-602
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• 2003

In this paper, we proposed new buffer management and cell scheduling scheme of GFR service for improving fairness of TCP/IP traffic in ATM networks. The proposed algorithm used untagged cell, which came to ATM switch, to decide the policy for discard of frame and what kind of VC cell it would serve. Performance analysis through the simulation present that proposed scheme can meet fairness 2 (MCR Plus equal share), which are not met by conventional scheduling mechanism such as WRR. Also, proposed scheme is superior to WRR about 30% in throughput and more efficiency in fairness criteria.

• Transactions of the KSME C: Technology and Education
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• v.3 no.4
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• pp.307-312
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• 2015

The passenger boarding bridge which provides a safe and comfort passenger pathway between an airplane and airport terminal gate is one of the apron equipment. This study investigates the effect of the lift column layout design on structural strength of the passenger boarding bridge by using finite element method, comparing deflection and stress. The overlapped zone of the tunnel frame A and B occurred at the maximum stress. The results of this research show that the lift column layout design is closely the value of the maximum stress.

• The KIPS Transactions:PartC
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• v.15C no.6
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• pp.567-572
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• 2008

It is necessary to study about the scheme to accept IP traffic effectively in OTN, according to expect that IP traffic data will be increase constantly. In this paper, we studied the encapsulation method of IP traffic through GFP in OTN transmission network. Therefore we knew the IP/GFP/OTN method is more efficient than existing methods from structure, overhead rates and possibility of grow, and showed the functional block of high level about this method. Also we showed the implementation scheme of this method by processing the functional simulation to make use of VHDL programming.