• Journal of information and communication convergence engineering
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• v.13 no.3
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• pp.167-171
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• 2015

A radio over fiber (RoF) system is a kind of analog optical transmission system and considered as a strong candidate for the next-generation fronthaul link in the future mobile network. In RoF systems, nonlinearity compensation is essential to increase the link capacity. In this paper, we propose a nonlinearity detection and compensation scheme using a monitoring channel in RoF systems. A monitoring channel is added at the transmitter site and used for transmitting a reference signal in an RoF transmission. The nonlinearity in the RoF transmission is detected by comparing the received monitoring signal and the original reference signal at the receiver site. Finally, the nonlinearity is compensated at the receiver by giving the reverse function of the detected nonlinearity. Our results show that the proposed scheme can almost remove the error vector magnitude degradation induced by the nonlinearity in the RoF system.

• International Journal of Contents
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• v.8 no.3
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• pp.64-70
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• 2012

The purpose of this paper is to give some crisis communication strategies for effective cooperation and coordination among the countries in global society. Based on the theoretical discussions, in this paper, five strategic recommendations toward improving crisis communication are offered as follows; First, it is necessary that a small, dynamic team for global crisis communication function be established among the nearby countries. Second, for understanding the neighboring country's crisis situation, it is needed that the common crisis communication organizations which play an important role of disseminating accurate information and giving the collaborative efforts in each country have to be made. Third, for effective crisis management, an appropriate infrastructure that includes open and effective communication channels among different levels and across organizations must be in place. Fourth, mass communication should fulfill a variety of functions in society and provide information, interpretation of events, and its influence, etc for cooperating and coordinating the crisis management. Fifth, to acquire a correct understanding of the bordering country's crisis and calamities, intercultural education program should be established in the crisis communication system.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.6 s.324
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• pp.87-92
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• 2004

Several stubs are added to a rectangular slot for giving an improvement in both return loss and isolation for a slot-coupled microstrip directional coupler. Its closed-form design equations are derived by velocity equalization of two normal modes and network equivalence. It was verified that nearly ideal performance is achievable by design examples.

• Language and Information
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• v.17 no.1
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• pp.17-32
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• 2013

Birner (1998) analyzes the construction of inversion within the centering theory, claiming that the preposed constituent in the inversion structure represents the backward-looking center that connects the current utterance to the previous discourse. However, this paper refutes such a strong claim, pointing out various problems of her work. Instead, this paper argues that the preposed element in the inversion construction is merely the preferred center under the condition that the ranking of the forward-looking centers is determined by the surface word order, rather than by grammatical relations. Thus, this paper claims that the discourse function of the construction of inversion is not text development but merely prominence-giving, in the sense of Ili$\acute{c}$ (1998).

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.5
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• pp.90-102
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• 1993

In this paper, we propose a prgressive image transmission technique using hierarchical pyramid data structure which is constructed based on the projection data of an image. To construct hierarchical Gaussian pyramids, we first divide an image into 4$\times$4 subblocks and generate the projection data of each block along the horizontal, vertical, diagonal, and antidiagonal directions. Among images reconstructed by backprojecting the projection data along a single direction, the one giving the minimum distortion is selected. The Gaussian pyramid is recursively generated by the proposed algorithm and the proposed Gaussian images are shown to preserve edge information well. Also, based on the projection concept a new transmission scheme of the lowest Laplacian plane is presented. Computer simulation shows that the quantitative performance of the proposed pyramid coding technique using projection concept is similar to those of the conventional methods with transmission rate reduced by 0.1 ~ 0.2 bpp and its subjective performance is shown to be better due to the edge preserving property of a projection operation.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.6
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• pp.82-87
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• 2006

Availability of defect test algorithm that recognizes exact and standardized defect information in order to fundamentally resolve generated defects in industrial sites by giving artificial intelligence to SAT(Scanning Acoustic Tomograph), which previously depended on operator's decision, to find various defect information in a semiconductor package, to decide defect pattern, to reduce personal errors and then to standardize the test process was verified. In order to apply the algorithm to the lately emerging Neural Network theory, various weights were used to derive results for performance advancement plans of the defect test algorithm that promises excellent field applicability.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.159-163
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• 2003

The term "VPN", or Virtual Private Network, generally means the public network of vendors which is providing a communication net and other network using WWW as a backbone of Its WAN. the existing VPN is expected to reduce expenses and will improve the productivity, however, the network provider should accept the management complexity and the overhead after tunneling and encryption. But MPLS VPN can provide efficient VPN which would not need the address transformation and the additional overhead made by tunneling after giving separately ID. This paper describes the protocol for MPLS VPN which is about a node that moves based on Customer Edge (CE) router and supports a scheme for QoS.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.12 no.6
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• pp.599-606
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• 1987

Giving a high degree of intelligence to the electronic equipments such as communication system is the general trend of nowadays. Therefore the multi-processor will be required in a single system and the switch gives an example of it. In this paper, "Reserved Bus" is proposed as the interprocessor communication method applicable to such system which has multi-processor in the limited space. The performance of proposed method is also analyzed. analyzed.

• Journal of the Korean Society for Library and Information Science
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• v.33 no.4
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• pp.113-131
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• 1999

This study is a nationwide survey of Korean public libraries to identify and analyze the usefulness of 69 evaluation indicators of a public library proposed by the authors in the previous paper. A random sample of respondents including library managers, librarians, and users rated the usefulness of each indicator in assessing the performance of a public library. The results of this study could be used as the basic data in the evaluation of public libraries by selecting appropriate indicators and giving weight on each indicator according to the specific evaluation purpose.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.12 no.3
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• pp.285-291
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• 1987

Seismic waves are attenuated by losses of energy as they propagate through the earth. One way to model this numerically is to make the velocity a complex number, the real part giving the phase velocity and the imaginary part the attenuation. This models wave propagation in a medium for which the logarithmic decrement is independent of frequency(attenuation coefficient is proportional to frequncy). The aim is to modify forward and inverse numerical modeling so that attenuation can be specified as a function of position.