• Journal of Intelligence and Information Systems
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• v.12 no.2
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• pp.167-183
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• 2006

Since data mining attempts to find unknown facts or rules by dealing with also vaguely-known data sets, it always suffers from high error rate. In order to reduce the error rate, many researchers have employed multiple models in solving a problem. In this research, we present a new type of multiple models, called DyMoS, whose unique feature is that it classifies the input data and applies the different model developed appropriately for each class of data. In order to evaluate the performance of DyMoS, we applied it to a real customer churn problem of an automobile insurance company, The result shows that the DyMoS outperformed any model which employed only one data mining technique such as artificial neural network, decision tree and case-based reasoning.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.6
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• pp.1234-1242
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• 2004

In this paper, the characteristics of compensation for interferenced mid-channel signal by neighbor channels through four-wave mixing (FWM) process dominantly is investigated as a function of channel input power, fiber dispersion coefficient and transmission length in WDM system with equally spaced channels. The compensation method used in this research is mid-span spectral inversion(MSSI). The highly nonlinear dispersion shifted fiber (HNL-DSF) is used as a nonlinear medium of optical phase conjugator (OPC) in order to compensate wideband WDM signals. First, we confirmed that the effect of FWM on channel interference is gradually reduced as fiber dispersion coefficient becomes gradually smaller, independent of signal format. And, we confirmed that RZ is better than NRZ as a modulation format for transmitting high power channel with allowable reception quality. But realization of flexible WDM systems regardless of channel number variation is possible by using NRZ rather than RZ format.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.3
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• pp.597-604
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• 2011

The various Smartphone platforms that are used currently make difficult to build efficient applications("apps") for Smartphone. Introduction of middleware in the Smartphone environment is being studied to solve this problem. By enhancing interoperability between server systems and Smartphone platforms as introducing this middleware supports efficiently for Smartphone apps to be developed and managed. Thus, the development of this middleware for Smartphone has become essential for the purpose of responding actively to the rapidly expanding Smartphone market. In this research, we designed and implemented Smartphone middleware which optimizes the cost and time for developing new application service and maintaining it. In order to test this implemented middleware's performance and its capabilities, we also developed university Smartphone apps and activated campus twitter.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.250-251
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• 2015

The situation requires a global alternative energy resources due to the lack of rapid consumption of fossil fuel and nuclear fuel that occurs in nature. There are a number of alternative energy research and development in the world today. Of which there is an existing wind power generation system has been developed into a large-scale systematic trend of small wind power systems have created a wind power generation system using a simple principle. Existing small wind turbine system is a situation that is in many places a deterioration odor problems and maintenance of power generation efficiency because it came to be developed systematically. In this paper, we developed a hybrid power system that can develop the solar energy at the same time as the increase in the small wind power generation efficiency and the system to develop that can efficiently maintain the hybrid power generation system through the network.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.1041-1043
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• 2013

As the mobile device supply is increasing currently, the era of N mobile devices per person has opened. Types of mobile devices and OS are increasing continuously. Samsung and Intel are developing TIZEN, the OS mobilized by UBUNTU of Linux is going to be released as well as the market share of Google's Android and Apple's IOS remains above 90%. However, it is a reality that there are not specific technologies or systems which can share files between different OS. Despite of technologies such as Bluetooth and WiFi Direct, constraints are shown in device compatibility and file formats. In this paper, we have studied how to share files between OS as well as mobile devices, and to share files in a wireless LAN environment of heterogeneous variety. Future research includes the mobile phone integration server system that provides services such as introduction, management, maintenance, and repair in one-touch Mobile Server that spread and building are easy.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.5C
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• pp.542-549
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• 2007

Recently, many research activities in the image processing area are concentrated on developing new algorithms by finding the solution of the 'diffusion equation'. The diffusion algorithms are expected to be utilized in numerous applications including noise removal and image restoration, edge detection, segmentation, etc. In this paper, at first, it will be shown that the anisotropic diffusion algorithms have the similar structure with the adaptive FIR filters with cross-shaped 5-tap kernel, and this relatively small-sized kernel causes many iterating procedure for satisfactory filtering effects. Moreover, it will also be shown that lots of modifications which are adopted to the conventional Gaussian diffusion method in order to weaken the edge blurring nature of the linear filtering process increases another computational burden. We propose a new Median diffusion scheme by replacing the adaptive linear filters in the diffusion process with the AWM (Adaptive Weighted Median) filters. A diffusion-equation-based adaptation scheme is also proposed. With the proposed scheme, the size of the diffusion kernel can be increased, and thus diffusion speed greatly increases. Simulation results shows that the proposed Median diffusion scheme outperforms in noise removal (especially impulsive noise), and edge preservation.

• Journal of Information Processing Systems
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• v.8 no.2
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• pp.375-388
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• 2012

PVSS stands for publicly verifiable secret sharing. In PVSS, a dealer shares a secret among multiple share holders. He encrypts the shares using the shareholders' encryption algorithms and publicly proves that the encrypted shares are valid. Most of the existing PVSS schemes do not employ an ElGamal encryption to encrypt the shares. Instead, they usually employ other encryption algorithms like a RSA encryption and Paillier encryption. Those encryption algorithms do not support the shareholders' encryption algorithms to employ the same decryption modulus. As a result, PVSS based on those encryption algorithms must employ additional range proofs to guarantee the validity of the shares obtained by the shareholders. Although the shareholders can employ ElGamal encryptions with the same decryption modulus in PVSS such that the range proof can be avoided, there are only two PVSS schemes based on ElGamal encryption. Moreover, the two schemes have their drawbacks. One of them employs a costly repeating-proof mechanism, which needs to repeat the dealer's proof at least scores of times to achieve satisfactory soundness. The other requires that the dealer must know the discrete logarithm of the secret to share and thus weakens the generality and it cannot be employed in many applications. A new PVSS scheme based on an ElGamal encryption is proposed in this paper. It employs the same decryption modulus for all the shareholders' ElGamal encryption algorithms, so it does not need any range proof. Moreover, it is a general PVSS technique without any special limitation. Finally, an encryption-improving technique is proposed to achieve very high efficiency in the new PVSS scheme. It only needs a number of exponentiations in large cyclic groups that are linear in the number of the shareholders, while all the existing PVSS schemes need at least a number of exponentiations in large cyclic groups that are linear in the square of the number of the shareholders.

• Journal of Information Processing Systems
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• v.8 no.1
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• pp.55-66
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• 2012

This paper presents a dual modeling method that simulates the graphic and haptic behavior of a volumetric deformable object and conveys the behavior to a human operator. Although conventional modeling methods (a mass-spring model and a finite element method) are suitable for the real-time computation of an object's deformation, it is not easy to compute the haptic behavior of a volumetric deformable object with the conventional modeling method in real-time (within a 1kHz) due to a computational burden. Previously, we proposed a fast volume haptic rendering method based on the S-chain model that can compute the deformation of a volumetric non-rigid object and its haptic feedback in real-time. When the S-chain model represents the object, the haptic feeling is realistic, whereas the graphical results of the deformed shape look linear. In order to improve the graphic and haptic behavior at the same time, we propose a dual modeling framework in which a volumetric haptic model and a surface graphical model coexist. In order to inspect the graphic and haptic behavior of objects represented by the proposed dual model, experiments are conducted with volumetric objects consisting of about 20,000 nodes at a haptic update rate of 1000Hz and a graphic update rate of 30Hz. We also conduct human factor studies to show that the haptic and graphic behavior from our model is realistic. Our experiments verify that our model provides a realistic haptic and graphic feeling to users in real-time.

• Journal of the Korea Society of Computer and Information
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• v.13 no.7
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• pp.127-138
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• 2008

Configuration and data management system for weapon system research and development processes should assist concurrent engineering and collaboration activities for various documents, drawings, part informations and product structure informations. In this thesis we defined the system architecture using the CBD methodology and implemented the component based system development process. Most of the configuration and data management systems consist of three layered system architecture which use the general MVC models. In this thesis we defined four layered system architecture based on EJB structure under J2EE environments. Through the four layered system architecture, we break down the general model layer into two detailed business layers and the ordinary control layer into two system dependent layers. With these four layers, we proposed the methodology that detailed the characteristics of the components. Through the CBD approach and the component based development process, we can get the representation model and implement the actual system of the configuration and data management system for weapon system R&D.

• Journal of the Korea Society of Computer and Information
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• v.18 no.5
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• pp.69-76
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• 2013

In the recent years, cyber attacks by malicious codes called malware has become a social problem. With the explosive appearance and increase of new malware, innumerable disasters caused by metaphoric malware using the existing malicious codes have been reported. To secure more effective detection of malicious codes, in other words, to make a more accurate judgment as to whether suspicious files are malicious or not, this study introduces the malware analysis system, which is based on a profiling technique using the Finite Automata. This new analysis system enables realtime automatic detection of malware with its optimized partial execution method. In this paper, the functions used within a file are expressed by finite automata to find their correlation, and a realtime malware analysis system enabling us to give an immediate judgment as to whether a file is contaminated by malware is suggested.