• Journal of Digital Convergence
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• v.10 no.6
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• pp.341-347
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• 2012

Network Access Control system of medical asset protection solutions that installation and operation on system and network to provide a process that to access internal network after verifying the safety of information communication devices. However, there are still the internal medical-data leakage threats due to spoof of authorized devices and unauthorized using of users are away hours. In this paper, Network 2-Factor Access Control Model proposed for prevention the medical-data leakage by improving the current Network Access Control system. The proposed Network 2-Factor Access Control Model allowed to access the internal network only actual users located in specific place within the organization and used authorized devices. Therefore, the proposed model to provide a safety medical asset environment that protecting medical-data by blocking unauthorized access to the internal network and unnecessary internet access of authorized users and devices.

• Journal of Electrical Engineering and information Science
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• v.3 no.1
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• pp.21-27
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• 1998

In this paper we apply routing algorithms in circuit switched networks to B-ISDN networks and investigate the performance. B-ISDN supports a wide range of services with hetrogeneous bandwidth requirements. We assume that the network supports D classes of traffic. It is modeled as a finite D dimensional Markov chain. A call is blocked on arrival if the required bandwidth is not available on the route. The shortest path routing, alternate routing and trunk reservation are considered for performance comparison. We also consider trunk reservation with restricted access control where the network reserves certain amount of bandwidths for one class of traffic that assumes a higher transmission priority. Through the method of successive iterations, we obtain the steady state equilibrium probabilities and call blocking probabilities for dynamic routing. The results can be used to design a B-ISDN network that improves network connection availability and efficiency while simultaneously reducing the network costs.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.2
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• pp.1-7
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• 1996

In this paper, we analyzed the packet blocking probability of a finite buffer in a network interface unit. In general, a network interface unit which provides a means of interface between the network and computer has a microprocessor and a protocol processor for the network access protocols. It also has a receive buffer for the arriving packets from the network which is served by the microprocessor with service interruption by the protocol processor. In this paper, we modeled the receive buffer as a discrete time server with service interruption, and obtained the packet blocking probability using the mini-slot approximation.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.1616-1640
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• 2006

In this paper, we deal with a network optimization problem arising from the deployment of Ethernet-based BcN access network. BcN convergence services require that access networks satisfy QoS measures. BcN services have two types of traffics: stream traffic and elastic traffic. Stream traffic uses blocking probability as a QoS measure, while elastic traffic uses delay factor as a QoS measure. Incorporating the QoS requirements, we formulate the problem as a nonlinear mixed-integer programming model. The proposed model seeks to find a minimum cost dimensioning solution, while satisfying the QoS requirement. We propose tabu search heuristic algorithms for solving the problem, and simulate tabu result. We demonstrate the computational efficacy of the proposed algorithm by solving a network design problem.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.3
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• pp.379-388
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• 1998

In this paper we propose a DMR-II shared-medium access control protocol which was developed for the ATM access network users to support isochronous and non-isochronous traffics simultaneously under the bandwidth sharing environment, and describe its architecture and operation principles. The DMR-II protocol uses the slotted-ring topology, and gives the higher transmission priority to the isochronous traffic than the non-isochronous traffic. To support the isochronous traffic it uses the slot reservation mechanism, and maintains the delay variation of the isochronous traffic beyond the threshold value by using the blocking mechanism whenever the total user traffic overflows the network's bandwidth limitation. for the non-isochronous traffic the DMR-II protocol lets all the nodes to have fair transmission chances by using the reset mechanism based on the window counter scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.9B
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• pp.1624-1630
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• 1999

Code division multiple access (CDMA) is a promising air interface technique for cellular systems. When an MS (Mobile Station) moves to an adjacent cell, the handoff between the serving cell and the target cell is needed. Compared with the hard handoffs, the soft handoffs between two CDMA channels with the identical frequency assignments and frame offsets can provide a better quality of service by minimizing the undesirable ping pong phenomenon of back-and forth handoffs between two adjacent cells in conventional hard handoffs. For the soft handoff of a call to an adjacent cell to be successful, the adjacent cell should assign to the call the same frame offset as that being used in the original cell by the call. In this paper, considering the assignment states of the frame offsets of the adjacent cells, a frame offset assignment algorithm for the originated call is proposed. And analytic method for the handoff blocking probability due to the lack of the frame offset capacity is also presented to show the advantage of the proposed algorithm with respect to the soft handoff blocking probability.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.5
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• pp.665-675
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• 2001

In this paper, the reverse link performance of a imperfect power controlled DS/CDMA cellular system that uses a base station array antenna which can effectively remove the multiple access interference is analyzed considering both beam forming algorithm and power control error in shadowing. The blocking probability of the DS/CDMA cellular system based on array parameters, $E_b/N_o$ and statistics of interference is derived, and then the system capacity corresponding to a certain blocking probability is calculated. On the assumption that the blocking probability is set 1%, the system capacity using MCGM algorithm with 12 antenna arrays is more increased maximum 32 times than that using a omni-directional antenna and about 2 times than that using MMSE algorithm, respectively.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.6
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• pp.463-475
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• 2009

Flash memory is suitable for real time systems because of its consistent performance for random access, low power consumption and shock resistance. However, flash memory needs blocking time to perform a garbage collection to reclaim invalidated pages. Moreover, the worst-case garbage collection time is significantly longer than the best-case garbage collection time. In this paper, we propose a FTL (Flash Translation Layer) mapping scheme called KAST (K-Associative Sector Translation). In the KAST scheme, user can control the maximum association of the log block to limit the worst-case garbage collection time. Performance evaluation using simulation shows that not only KAST completes the garbage collection within the specified time but also provides about 10~15% better average performance than existing FTL schemes.

• JSTS:Journal of Semiconductor Technology and Science
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• v.3 no.4
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• pp.205-210
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• 2003

A 3-Transistor cell CMOS OTP ROM array using standard CMOS antifuse (AF) based on permanent breakdown of MOSFET gate oxide is proposed, fabricated and characterized. The proposed 3-T OTP cell for ROM array is composed of an nMOS AF, a high voltage (HV) blocking nMOS, and cell access transistor, all compatible with standard CMOS technology. The experimental results show that the proposed structure can be a viable technology option as a high density OTP ROM array for modern digital as well as analog circuits.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06d
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• pp.91-94
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• 2010

기업 내에서 메신저 사용으로 인한 정보 유출이나 근무태만에 대하여 대처하기위해 메신저 사용을 차단하는 방법은 제안한다. 차당방법을 제안하기에 앞서 현재 범용의 메신저를 실제 IP 스니핑을 통한 테스트로 구조를 분석하고 그 분석된 구조를 바탕으로 메신저 차단 제어의 3가지 방법을 제안 한다.