• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.6B
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• pp.331-337
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• 2005

The optical Internet is considered as a feasible solution for transporting huge amount of traffic volume in the future Internet. Among optical switching technology for the optical Internet, OBS becomes one of the most promoting solution. Recently, a lebeled OBS(LOBS) architecture is considered for an efficient control on OBS network. Given that a data burst may contain few thousands of IP packets, a single loss of data burst results in a serious throughput degradation in LOBS network. In this paper, we improve the performance of LOBS network by introducing the burst congestion control mechanism. More specifically, the OBS router at the network core detects the network congestion by measuring the loss probability of burst control packet. The OBS router at the network edge reduces the burst generation according to the network condition repored by the OBS router at the network core. Through the simulations, it is shown that the proposed congestion control mechanism can reduce the burst loss probability and improve the LOBS network throughput.

• The KIPS Transactions:PartC
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• v.19C no.1
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• pp.29-38
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• 2012

Due to rapid spread of smart phones and SNS(Social Network Service), using of Internet applications has increased and taking up bandwidth more than 3G network's capacity recently. This caused reduction of speed and service quality, and occurred strong needs that backbone network company to increasing investment costs. Also a great rise of mobile network users causing identity management problems on mobile service provider through mobile network. This paper proposes advanced IDM3G[1] - to solve user ID management and security problems on mobile internet application services over 3G network and more - authentication management protocol. $I^2DM$ protocol breakup loads which made by existing IDM3G protocol's mutual authentication via mobile operator, via sending some parts to internet application service provider, enhancing mobile and ID management of service provider and network load and process load from information handling and numbers of transmitting packets, to suggest more optimized protocol against further demanding of 3G mobile network.

• Korean Management Science Review
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• v.27 no.1
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• pp.17-31
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• 2010

Patients entering an emergency care center in a hospital usually visit medical processes in different orders depending on the urgency level and the medical treatments required. We formulate the patient flows among diverse processes in an emergency care center using the Jackson network, which is one of the queueing networks, in order to evaluate the system performances such as the expected queue length and the expected waiting time. We present a case study based on actual data collected from an emergency care center in a hospital, in order to prove the validity of applying the Jackson network model in practice. After assessing the current system performances, we provide operational strategies to reduce waiting at the bottleneck processes and evaluate the impact of those strategies on the entire system.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.64-68
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• 2007

Commercial WiBro and 3G HSDPA services are launched last year in order to provide high speed wireless Internet access and multimedia service. Currently mobile communication service providers concentrate on the deployment of indoor mobile network since indoor traffic is remarkably increased. For fine indoor wireless communication, an installation of access point system via Public IP network which is called Femtocell is required. The development of indoor Femtocell system must be considered in the viewpoint of low hardware complexity, cost reduction, interlocking with WiBro/HSDPA network without change of network component and easy element management. In this paper, we review the implementation issue and technology of dual mode AP which provides WiBro and HSDPA signal to the user simultaneously. Especially, we describe on the HSDPA Femtocell standardization status and possible 3 types of HSDPA communication module development design. Furthermore we analyze the merits and demerits of each HSDPA Femtocell design type and propose a system which enables handover between indoor HSDPA Femtocell and outdoor commercial HSDPA mobile network.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.4
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• pp.175-180
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• 2002

In order to satisfy the requirements of time reduction and cost saving for development of electronic control systems(ECU) in automotive industry, the applications of a standardized real-time operating system(RTOS) and a communication protocol to ECUs are increased. In this study, a body control module(BCM) that employs OSEK/VDX(open system and corresponding interfaces for automotive electronics/vehicle distributed executive) OS tour the RTOS and a controller area network(CAN) fur the communication protocol is designed, and the performances of the system are evaluated. The BCM controls doors, mirrors, and windows of the vehicle through the in-vehicle network. To identify all the transmitted and received control messages, a PC connected with the CAN communication protocol behaves as a CAN bus emulator. The control system based upon in-vehicle network improves the system stability and reduces the number of wiring harness. Furthermore it is easy to maintain and simple to add new features because the system is designed based on the standards of RTOS and communication protocol.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.7A
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• pp.557-562
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• 2003

An output multiplexer of manifold type is widely used in a recent satellite transponder for its mass and volume reduction. For correct operation, the filters of such a multiplexer must be singly terminated. In this paper, a simple synthesis method of a 6-pole dual-mode singly-terminated filter is described. From the transfer function of the filter, network parameters such as in/output terminations and coupling coefficients are obtained easily without complicated matrix algebra such as orthogonal projection and similarity transformation. Two different-structure filters are taken into consideration and the network parameters of each filter have been extracted from the same transfer function. It is shown that the responses of two filters are same to each other since their network parameters are obtained from the same transfer function. The method described in this paper can be applied to the other degree singly terminated filter.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.3 s.303
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• pp.129-136
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• 2005

To reduce the noise in the noisy speech, it is desirable to change the parameters of the speech processing system according to the noise intensity to reproduce a good quality speech. This paper proposes an estimation method of noise intensity using a three layered neural network, which is able to learn the three graded speeches that is degraded by white noise or road noise. Experimental results demonstrate that the noise intensity could be estimated by the neural network. Even if the speakers and speech data are different from the training data, estimation rates for the noise intensity can be estimated by the neural network with an average accuracy of $95\%$ or more for white noise.

• The Journal of Society for e-Business Studies
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• v.17 no.4
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• pp.141-153
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• 2012

According to the environment change of market, supply chain network needs to be redesigned for efficient provision of product within the budget constraint. Also, it is desired that the customer satisfaction such as on time delivery should be considered as an important element at redesigning of supply chain network in addition to the cost reduction. In this paper redesign of supply chain network for its expansion is treated as a problem situation and a related mathematical model is suggested. Moreover, the numerical examples about the total weighted distance of the redesigned supply chain network are presented with various budget constraints by using genetic algorithm to help the managerial decision.

• Korean Management Science Review
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• v.34 no.2
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• pp.15-33
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• 2017

This paper considers a Bayesian Network analysis for understanding the heterogeneous cross-category effects of different promotion activities and developing an efficient overall promotion strategy for a large retail store. More specifically we differentiate price reduction promotion and floor promotion and study their heterogeneous effect on consumer purchase behavior under a market basket setting. We then utilize Bayesian networks in identifying complex association structure in market basket dataset by analyzing the effects of different promotional activities and also include the effects of time, family income and size. We find from our Bayesian network analysis that the dominant cross-category promotion effect of price promotion is the indirect effect whereas the dominant cross-category promotion effect of floor promotion is the direct effect. Also, among the demographic variables we find that family size of the household is linked with more product categories compared to income and see that there are differences in the extent of the effects by product category. Finally, we also show the existence of products acting as a network hub and how they can be utilized by retailers faced with a limited marketing budget and suggest a more efficient promotion strategy.

• Journal of IKEEE
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• v.21 no.4
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• pp.420-423
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• 2017

In this paper, we propose an implementation of a neural network accelerator for reducing the rendering noise. Among the rendering algorithms, we selects a ray tracing to assure a high-definition graphics. Ray tracing rendering uses ray to render. Less use of the ray will result in noise, and if used too much, it will produce a higher quality image, but will take longer. In order to quickly process such lace rendering, an algorithm is used that uses less rays and removes the noise generated. Among such algorithms, there is an algorithm using a neural network, and a neural network accelerator which obtains a filter parameter used in an operation is implemented in order to speed up the operation speed. The time it takes to calculate the parameters used for a pixel is 11.44us.