• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.4
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• pp.812-822
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• 1997

In this paper, we propose an architecture of the asynchronous shared-bus type switch with priority and fairness schemes. The switch architecture is an input and output queueing system, and the priority scheme is implemented in both input and output queues. We analyze packet delay of both input and output queues. In the analysis, we consider to stations with asymmetric arrival rates. Although we make some approximations in the analysis, the numerical results show good agreements with the simulation results.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10a
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• pp.565-567
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• 2001

원자력 발전 및 항공 시스템과 같은 실시간 시스템의 설계는 자원 및 시간적인 분석은 상당히 중요한 부분을 차지하고 있다. 이러한 설계는 그 설계단계로부터 철저한 명세 및 집중이 이루어져야 한다. Statechart는 Reactive 시스템을 모델링 하는 도식언어이다. 하지만 기존 Statechart 언어는 자원에 대한 시간적 명세가 분명치 않아 상태로 모든 것을 표현하기에는 복잡하고 용이하지 않다. 또만 이러한 명세 도구는 시스템의 검증은 물론 시간적 행위의 검증은 수월치 한다. 본 논문은 Statechart에 시간을 소모하는 자원을 명세하는 문법을 소개하고 이를 검증하는 기법을 제시하고자 한다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04b
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• pp.214-216
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• 2004

XML 문서에 대한 데이터의 통계 정보는 XML 어플리케이션에 유용하다. 특히 XML 어플리케이션에 대해 RDBMS 테이블 형U로 유도하는 방법 중 cost-based approach를 적용할 때 다양한 Schema 변환 중 어플리케이션에 가장 적합한 것을 선택하는 데 사용한다. 본 논문에서는 정차한 통계 정보를 모으기 위해 Shared type과 변환 과정에 생기는 잠재적인 Shared type에 대해 해결한 X2R System을 개발하였고. 효율적으로 통계를 유지하도록 하였다.

• The Transactions of the Korea Information Processing Society
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• v.5 no.4
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• pp.873-882
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• 1998

The parallel database machine approach is currently widely and successfully used. There are four major architectures which are used in this approach: shared-nothing architecture, shared-evertying architecture, shared-disk architecture, and hybrid architecture. In this paper, we use an analytical model to evaluate the performance of these database machine architectures. We define an abstract model for each type of database machine design to obtain performance equatons describing the execution times with respect to the hybrid hash join poeration. Using the performance equations, we evaluate the execution times of the various database machine design models.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10c
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• pp.483-487
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• 2006

단말의 이동성을 지원하는 Mobile IP에서 MN이 홈 네트워크에서 먼 곳으로 이동하는 경우, 매번 BU 시그널링을 하게 되면 Registration latency가 길어져, 이로 인해 불필요한 네트워크 트래픽을 유발한다. 따라서 계층을 두어 지역적인 이동성을 관리하는 MAP을 도입한 HMIPv6가 제안되었다. HMIPv6는 지역적인 LCoA와 외부에 노출되는 RCoA를 가진다. Mobile IP 환경에서의 BU메시지 취약성은 보안이슈가 되어왔으며, HMIPv6은 두 개의 CoA를 가지므로 보안위협은 배가된다. 본 논문에서는 Static Shared Key를 사용하여 HMIPv6의 LCoA BU 시그널링 관련 메시지의 인증을 제안함으로써 Mobile WG에서 제기된 BU 시그널링의 보안 취약성을 개선하였다.

• Journal of the Korea Society of Computer and Information
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• v.3 no.2
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• pp.169-175
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• 1998

There is a shared multibuffer method which can preventing HOL blocking in ATM switch. However, the system still has a problem that reduces the performance of the system because of the cell loss. Therefore, in this paper, preventing of cell loss in non-contentional shared multibuffer switch is suggested. To prevent cell loss, a structure is suggested that a cell can be loss in a certain slot time is stored in the dedicated temporary memory so the cell can be transferred in the next slot time. The simulation result of the structure, this suggested system superior performance than the exited system in cell loss rate and throughput.

• Journal of Korea Society of Digital Industry and Information Management
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• v.12 no.4
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• pp.71-79
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• 2016

This study proposes a performance model of a shared bus multi-processor system and analyzes the effect of input/output types on system performance and overload of shared resources. This system performance model reflects the memory reference time in relation to the effect of input/output types on shared resources and the input/output processing time in relation to the input/output processor, disk buffer, and device standby places. In addition, it demonstrates the contribution of input/output types to system performance for comprehensive analysis of system performance. As the concept of workload in the probability theory and the presented model are utilized, the result of operating and analyzing the model in various conditions of processor capability, cache miss ratio, page fault ratio, disk buffer hit ratio (input/output processor and controller), memory access time, and input/output block size. A simulation is conducted to verify the analysis result.

• ETRI Journal
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• v.27 no.6
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• pp.725-732
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• 2005

The reconfiguration management scheme changes a logical topology in response to changing traffic patterns in the higher layer of a network or the congestion level on the logical topology. In this paper, we formulate a reconfiguration scheme with a shared buffer-constrained cost model based on required quality-of-service (QoS) constraints, reconfiguration penalty cost, and buffer gain cost through traffic aggregation. The proposed scheme maximizes the derived expected reward-cost function as well as guarantees the required flow's QoS. Simulation results show that our reconfiguration scheme significantly outperforms the conventional one, while the required physical resources are limited.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.326-328
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• 2021

The use of shared electric kickboards that can move quickly within a short distance at a relatively low price is increasing significantly. In this paper, we propose a system for recognizing incorrect parking of an abandoned shared kickboard by applying deep learning-based object recognition technology. In this paper, a model similar to CNN was created separately considering the characteristics of the experimental data, and it was shown that a recognition rate of 60% was obtained through the experiment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2B
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• pp.162-169
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• 2009

Message Authentication Code (MAC) assures integrity of messages. In Mobile WiMAX, 128-bit Cipher-based MAC (CMAC) is calculated for management messages but only the least significant half is actually used truncating the most significant 64 bits. Naming these unused most significant 64bits Shared Authentication Information (SAI), we suggest that SAI can be applied to protect the network from DDoS attack which exploits idle mode vulnerabilities. Since SAI is the unused half of CMAC, it is as secure as 64bits of CMAC and no additional calculations are needed to obtain it. Moreover, SAI doesn't have to be exchanged through air interface and shared only among MS, BS, and ASN Gateway. With these good properties, SAI can efficiently reduce the overheads of BS and ASN GW under the DDoS attack.