• 한국경영과학회지
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• 제32권2호
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• pp.89-97
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• 2007

We study the maximum integer multiflow problem and the minimum multicut problem in a ring network. Both problems in a general network are known to be NP-hard. In this paper, we develop polynomial time algorithms to solve the problems. We also prove that even In a ring network, maximum multiflow is not always integral, which implies that the amount of maximum integer flow does not always reach the minimum capacity of multicut.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2005년도 추계학술대회 및 정기총회
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• pp.361-364
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• 2005

As increasing the Internet traffic, many researches on access network are reported for end-to-end high-speed broadband network, where E-PON(Ethernet-Passive Active Network) is one of reasonable candidate fur the network with respect to cost and bandwidth utilization. For the high-speed access network, E-PON need an efficient bandwidth allocation method. This paper suggests a WFA(Water-Filling Allocation) algorithm for the efficient bandwidth allocation with various simulation test.

• 한국경영과학회지
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• 제18권1호
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• pp.29-43
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• 1993

This paper condisers a problem of determining arc capacities for a communication network with fixed-charged linear arc-cost functions, which is known to be NP-hard. For the problem, an efficient heuristic solution procedure is derived. The procedure is further shown working well for designing arc capacities of a network in a situation where the network needs to be extended by connecting its nodes to some new nodes or where the network needs to be extended by expanding its arc capacities.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2003년도 춘계학술발표논문집 (중)
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• pp.1305-1308
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• 2003

Mobile Network은 일정한 규모 이상의 이동성을 지원하는 네트워치를 말한다. Mobile IP는 표준 IP에 이동성을 지원하기 위한 기법이다. Mobile IPv4에서는 Mobile Network을 가상적인 하나의 Mobile Node처럼 취급하여 지원이 가능하다. 하지만, Mobile IPv6에서는 몇몇의 문제점으로 인하여 Mobile IPv4에서와 같은 접근이 어렵다. 이 논문에서는 Mobile IPv6환경에서 Mobile Network을 지원할 수 있는 기법을 제안하고 분석하였다.

• 한국경영과학회지
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• 제26권3호
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• pp.65-77
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• 2001

Survivability of a network is one of the most important issues in designing present-day communication networks. the k-edge survivability of a given network is defined as the percentage of total traffic surviving the worst case failure of k edges. Although several researches calculated k-edge survivability on small networks by enumeration, prior research has considered how to calculate k-edge survivability on large networks. In this paper, we develop an efficient procedure to obtain lower and upper bounds on the k-edge survivability of a network.

• Journal of the Korean Data and Information Science Society
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• 제15권1호
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• pp.21-29
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• 2004

In this paper, we define an availability of repairable network system, when the states of links are modeled by alternating renewal processes. The actual availabilities of some well-known network systems are obtained. The expected numbers of failures and repairs of the network systems are also calculated.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2003년도 가을 학술발표논문집 Vol.30 No.2 (3)
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• pp.49-51
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• 2003

Developers of network games have used several prediction techniques for hiding transmission delay to support the real­time requirement of network games. Nowadays many researches that are related with network game are in progress to solve delay problems more radically, such as to propose new routers architecture and transport protocols suitable to characteristics of network game traffic. So for these advanced researches the tasks to grasp the traffic characteristics of a network game are needed. In this paper we aimed to capture the traffic of MMORPG and present the statistical analysis of measured data. The measurement and the analysis were accomplished with the server of 'Lineage' that regarded as the most successful MMORPG. Next, we have implemented a traffic generator that reflects the characteristics of MMORPG and shown that the trace generated by MMORPG traffic generator had identical characteristics with actual traffic using statistical testing method. We expect that this traffic generator can be used in many researches related with a network game.

• Journal of Communications and Networks
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• 제12권3호
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• pp.266-274
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• 2010

The efficient network resource management is one of the important topics in a real-time system. In this paper, we present a practical network resource management framework, control-theoretic packet scheduler (CPS) system. Using our framework, an operating system can schedule both input and output streams accurately and efficiently. Our framework adopts very portable feedback control theory for efficiency and accuracy. The CPS system is able to operate independent of the internal network protocol state, and it is designed to schedule packet streams in fine-grained time intervals to meet the resource requirement. This approach simplifies the design of the CPS system, and leads us to obtain the intended output bandwidth. We implemented our prototype system in Linux, and measured the performance of the network resource management system under various network QoS constraints. The distinctive features of our principles are as follows: It is robust and accurate, and its operation is independent of internal network protocols.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권12호
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• pp.3991-4007
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• 2022

In the public healthcare, a computational system that can automatically and efficiently detect and classify falls from a video sequence has significant potential. With the advancement of deep learning, which can extract temporal and spatial information, has become more widespread. However, traditional 3D CNNs that usually adopt shallow networks cannot obtain higher recognition accuracy than deeper networks. Additionally, some experiences of neural network show that the problem of gradient explosions occurs with increasing the network layers. As a result, an enhanced three-dimensional ResNet-based method for fall detection (3D-ERes-FD) is proposed to directly extract spatio-temporal features to address these issues. In our method, a 50-layer 3D residual network is used to deepen the network for improving fall recognition accuracy. Furthermore, enhanced residual units with four convolutional layers are developed to efficiently reduce the number of parameters and increase the depth of the network. According to the experimental results, the proposed method outperformed several state-of-the-art methods.

• Current Optics and Photonics
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• 제7권1호
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• pp.47-53
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• 2023

We propose a centralized passive-optical-network monitoring scheme using the resonance-spectrum properties of a Fabry-Perot cavity based on fiber Bragg gratings. Each cavity consists of two identical uniform fiber Bragg gratings and a varying cavity length or grating length, which can produce a unique single-mode resonance spectrum for the drop-fiber link. The output spectral properties of each cavity can be easily adjusted by the cavity length or the grating length. The resonance spectrum for each cavity is calculated by the transfer-matrix method. To obtain the peak wavelength of the resonance spectrum more accurately, the effective cavity length is introduced. Each drop fiber with a specific resonance spectrum distinguishes between the peak wavelength or linewidth. We also investigate parameters such as reflectivity and bandwidth, which determine the basic performance of the fiber Bragg grating used, and thus the output-spectrum properties of the Fabry-Perot cavity. The feasibility of the proposed scheme is verified using the Optisystem software for a simplified 1 × 8 passive optical network. The proposed scheme provides a simple, effective solution for passive-optical-network monitoring, especially for a high-density network with small end-user distance difference.