• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년 학술대회 논문집 정보 및 제어부문
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• pp.473-475
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• 2006

FieldBus communication systems in industrial wired and wireless network may cause the degradation of the TCP performance due to the racket loss. TCP is particularly targeted at the wired networks, a packet loss is assumed to be caused by the network congestion. As a result, the performance of TCP decreases significantly when used over networks that exhibit a high bit error rate. In order to solve this problem, this paper designs and implements the WFSnoop mechanism which offers a fast local retransmission. The proposed mechanism does not require any changes in customer premises. Base on the simulation in the wired and wireless network environment, we analyzed the performance of the WFSnoop mechanism.

• 한국음향학회지
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• 제11권1호
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• pp.14-21
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• 1992

본 연구에서는 통신망의 음성품질 기준을 설정하기 위하여, 음성품질 열화요인 중 음량정격 및 측음 마스킹 정격에 대한 일련의 주관평가를 실시하여, 음량정격과 평균 오피니언 점수 및 측음 마스킹 정격과 평균 오피니언 점수와의 상관을 구하였다. 또한 음성품질에 대한 사용자 백분율을 도출하여 사용자의 오피니언을 기본으로 하는 음성품질 기준을 제안하였다.

• 한국통신학회논문지
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• 제27권5C호
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• pp.465-473
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• 2002

In this paper the authors propose a theoretic framework to design the Virtual Private Network (VPN) via which the Quality of Services (QoSs) are guaranteed over IP networks. The required QoS is a very strict packet loss probability or a probability that packet delay does not exceed a certain target value in a statistical manner. QoSs are guaranteed by providing a statistical bandwidth similar to equivalent bandwidth, which is computed so that the provided bandwidth is sufficient to guarantee those requirements. Two typical network architectures are considered in constructing VPN, the customer pipe scheme and the Hose scheme, and we propose a method to compute the amount of the required bandwidth for the two schemes. Finally, we investigate the implication of the scheme via numerical experiments.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.469-475
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• 1991

In this paper, we suggest the exact perturbation analysis(Exact_PA) technique with respect to the buffer storage in tandem queueing networks, through which the optimal buffer storage design problem is considered. The discrete event dynamic equations for the departure time of a customer are presented together with the basic properties of Full Out(FO) and No Input(NI) with respect to the buffer storage. The new perturbation rules with respect to the buffer storage are suggested, from which the exact perturbed path can be obtained. The optimal buffer storage problem is presented by introducing a performance measure consisting of the throughput and the buffer storage cost. An optimization algorithm maximizing this performance measure is derived by using the Exact_PA technique. The proposed perturbation analysis technique and the optimization algorithm are validated by numerical examples.

• Journal of applied mathematics & informatics
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• 제22권1_2호
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• pp.523-533
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• 2006

We analyze two finite buffers queueing system with priority scheduling dependent upon queue length. Customers are classified into two types ( type-l and type-2 ) according to their characteristics. Here, the customers can be considered as traffics such as voice and data in telecommunication networks. In order to support customers with characteristics of burstiness and time-correlation between interarrival, the arrival of the type-2 customer is assumed to be an Markov- modulated Poisson process(MMPP). The service order of customers in each buffer is determined by the queue length of two buffers. Methods of embedded Markov chain and supplementary variable give us information for queue length of two buffers. Finally, performance measures such as loss and mean delay are derived.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.427-429
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• 2003

The reliability performance of distribution networks will be enhanced with the installation of application programs including feeder reconfiguration program for loss minimization and optimization of system capacity. Although the basic functions of remote monitoring and remote control provide no measurable cost benefit the suite of application programs developed and now being commissioned by KEPCO, the future will continue to offer this utility with substantial savings in system operational costs, improve system reliability and customer service.

• 디지털산업정보학회논문지
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• 제15권3호
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• pp.197-206
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• 2019

Telemarketing has been used in finance due to the reduction of offline channels. In order to select telemarketing target customers, various machine learning techniques have emerged to maximize the effect of minimum cost. However, there are problems that the class imbalance, which the number of marketing success customers is smaller than the number of failed customers, and the recall rate is lower than accuracy. In this paper, we propose a method that solve the imbalanced class problem and increase the recall rate to improve the efficiency. The hybrid sampling method is applied to balance the data in the class, and the stacked deep network is applied to improve the recall and precision as well as the accuracy. The proposed method is applied to actual bank telemarketing data. As a result of the comparison experiment, the accuracy, the recall, and the precision is improved higher than that of the conventional methods.

• Journal of Information Processing Systems
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• 제17권1호
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• pp.163-177
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• 2021

Many methods of discovering social networking communities or clustering of features are based on the network structure or the content network. This paper proposes a community discovery method based on topic models using a time factor and an unsupervised clustering method. Online community discovery enables organizations and businesses to thoroughly understand the trend in users' interests in their products and services. In addition, an insight into customer experience on social networks is a tremendous competitive advantage in this era of ecommerce and Internet development. The objective of this work is to find clusters (communities) such that each cluster's nodes contain topics and individuals having similarities in the attribute space. In terms of social media analytics, the method seeks communities whose members have similar features. The method is experimented with and evaluated using a Vietnamese corpus of comments and messages collected on social networks and ecommerce sites in various sectors from 2016 to 2019. The experimental results demonstrate the effectiveness of the proposed method over other methods.

• ETRI Journal
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• 제24권6호
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• pp.465-468
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• 2002

Ethernet passive optical networks (PONs) are an emerging access network technology that provides a low-cost method of deploying optical access lines between a carrier's central office and a customer site. In this paper, we propose a new algorithm of dynamic bandwidth allocation for multimedia services over Ethernet PONs. To implement the suggested dynamic bandwidth allocation algorithm, we present control message formats that handle classified bandwidths in a multi-point control protocol of Ethernet PONs.

• 한국경영과학회지
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• 제15권1호
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• pp.117-133
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• 1990

This paper is concerned with determining a minisum location with jockeying for a server on a probabilistic network in which each customer type enters the network system permitting with jockeying through a specified node and a nonpreemptive service policy is in effect. An algorithm to locate a single Fixed Priority Queue Median with Jockeying (FPQMJ) on acyclic networks is developed by using the Generalized Benders' Decomposition technique. The results are then extended to a general network.