• Journal of the Korea Society of Computer and Information
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• v.25 no.1
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• pp.63-69
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• 2020

In this paper, we propose an indoor positioning technique using the landmark based on relative Access Point (AP) signal strengths. The absolute values of AP signals are used to conventional indoor positioning technologies, but they may be different because of the difference of the measuring device, the measuring environment, and the timing of the measurements. However, we found the fact that the flow of the AP's RSSI in certain places shows almost constant patterns. Based on theses characteristics, we identify the relative strength between the APs and store the certain places as landmarks where they show certain patterns. Once the deployment of the landmark map is complete, system calculate position of user using the IMU sensor of smartphone and calibrate it with stored landmarks. Our system shows 75.2% improvement over technology that used only sensors, and 39.6% improvement over technology that used landmarks that were selected with absolute values.

• Journal of Broadcast Engineering
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• v.16 no.4
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• pp.573-583
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• 2011

In this paper, we propose an occlusion compensation algorithm which is used for virtual view generation. In general, since occlusion region is recovered from neighboring pixels by taking the mean value or median value of neighbor pixels, the visual characteristics of a given image are not considered and consequently the accuracy of the compensated occlusion regions is not guaranteed. To solve these problem, we propose an algorithm that considers primary visual characteristics of a given image to compensate the occluded regions by using seam carving algorithm. In the proposed algorithm, we first use Sobel mask to obtain the edge map of a given image and then make it binary digit 0 or 1 and finally thinning process follows. Then, the energy patterns of original and thinned edge map obtained by the modified seam carving method are used to compensate the occlusion regions. Through experiments with many test images, we verify that the proposed algorithm performed better than conventional algorithms.

• The KIPS Transactions:PartC
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• v.17C no.3
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• pp.223-232
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• 2010

Due to the advance of Internet, offline services are expanded into online services and a financial transaction company provides online services using internet baning systems. However, security problems of the internet banking systems are caused by a lack of security for developing the internet banking systems. Although the financial transaction company has applied existing internal and external standards, ISO 20022, ISO/IEC 27001, ISO/IEC 9789, ISO/IEC 9796, Common Criteria, etc., there are still vulnerabilities. Because the standards lack in a consideration of security requirements of the internet banking system. This paper is intended to explain existing standards and discusses a reason that the standards have not full assurance of security when the internet baning system is applied by single standard. Moreover we make an analysis of a security functions for the internet baning systems and then selects the security requirements. In this paper, we suggest a new protection profile of the internet baning systems using Common Criteria V.3.1 from the analysis mentioned above.

• Journal of Technology Innovation
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• v.23 no.3
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• pp.87-114
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• 2015

There are many government-led efforts for exploiting new growth engine to survive in a globally competitive environment. as a representative strategy, technology standardization policy is promoted by many countries. Although each country has unique characteristics in facilitating technology standardization, we can recently observe different strategy from conventional way like in United States. Thus, this study examines government-led technology standardization for activating emerging industry. Using case analysis, cloud computing is analyzed in terms of standardization organization and process perspectives, and technology standardization efforts by government in United States and Korea are compared. According to case analysis, this study investigates changes of the government-led standardization strategies for each country and suggests implications for activating emerging industry using technology standardization policy.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.3
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• pp.153-161
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• 2020

Due to the recent development of the 4th industrial revolution, Smart Factories that organically link various technologies such as AI, IoT, Cloud, and Big Data are increasing. Based on this, in the industrial environment where the internal process is controlled automatically, high availability should be secured against the loss caused when the internal process of the Smart Factory is stopped due to the determinism and malicious attack necessary to control the device such as PLC. The research and analysis of industrial network equipment and security equipment used in various industries can improve the efficiency and usability of industrial control systems in national infrastructure and can provide important feedback to build related infrastructure. Therefore, we compared industrial network equipment and security equipment in this paper in a variety of ways and expect to be used as a roadmap for developing technologies for industrial network equipment and industrial security equipment based on the results of this paper.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.6A
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• pp.575-583
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• 2002

JBIG2 is an International Standard fur compression of Bi-level images and documents. JBIG2 supports three encoding modes for high compression according to region features of documents. One of which is generic region coding for bitmap coding. The basic bitmap coder is either MMR or arithmetic coding. Pattern matching coding method is used for text region, and halftone pattern coding is used for halftone region. In this paper, a document is segmented into line-art, halftone and text region for JBIG2 encoding and JBIG2 CODEC is implemented. For efficient region segmentation of documents, region segmentation method using wavelet coefficient is applied with existing boundary extraction technique. In case of facsimile test image(IEEE-167a), there is improvement in compression ratio of about 2% and enhancement of subjective quality. Also, we propose arbitrary shape halftone region coding, which improves subjective quality in talc neighboring text of halftone region.

• The Journal of the Korea Contents Association
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• v.12 no.12
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• pp.63-70
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• 2012

In medical image processing field, object recognition is usually processed based on region segmentation algorithm. Region segmentation in the computing field is carried out by computerized processing of various input information such as brightness, shape, and pattern analysis. If the information mentioned does not make sense, however, many limitations could occur with region segmentation during computer processing. Therefore, this paper suggests effective region segmentation method based on R2-map information within the magnetic resonance (MR) theory. In this study, the experiment had been conducted using images including the liver region and by setting up feature points of R2-map as seed points for 2D region growing and final boundary correction to enable region segmentation even when the border line was not clear. As a result, an average area difference of 7.5%, which was higher than the accuracy of conventional exist region segmentation algorithm, was obtained.

• Journal of the Institute of Convergence Signal Processing
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• v.4 no.1
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• pp.36-40
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• 2003

A number of embedded wavelet image coding methods have been Proposed since the introduction of EZW(Embedded Zerotree Wavelet) algorithm. A common characteristic of these methods is that they use fundamental ideas found in the EZW algorithm. Especially, one of these methods is the SPIHT(Set Partitioning in Hierarchy Trees) algorithm, which became very popular since it was able to achieve equal or better performance than EZW without having to use an arithmetic encoder. The SPIHT algorithm is computationally very simple, but even so it provides excellent numerical and visual results. But the evaluation of its time complexity is no more than the relative result of experimental comparisons and the strict time complexity analysis wasn't taken until now. In this paper, we analyze strictly the processing time complexity of SPIHT algorithm and prove that the time complexity for one bit-plane processing is O( nlog $_2$n) in worst case.

• Journal of Energy Engineering
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• v.25 no.3
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• pp.114-129
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• 2016

Since the release of mid-term domestic GHG goals until 2020, in 2009, some various GHG reduction policies have been proposed to reduce the emission rate about 30% compared to BAU scenario. There are two types of modeling approaches for identifying options required to meet greenhouse gas (GHG) abatement targets and assessing their economic impacts: top-down and bottom-up models. Examples of the bottom-up optimization models include MARKAL, MESSAGE, LEAP, and AIM, all of which are developed based on linear programming (LP) with a few differences in user interface and database utilization. The bottom-up model for electric sector requires demand management, regeneration energy mix, fuel conversation, etc., thus it has a very complex aspect to estimate some various policies. In this paper, we suggest a bottom-up BAU model for electric sector and how we can build it through step-by-step procedures such that includes load region, hydro-dam and pumping storage.

• The Journal of the Korea Contents Association
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• v.7 no.11
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• pp.248-257
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• 2007

With the advance of information technology, e-learning is widely used. However, due to the lack of human computer interaction, e-mentoring or blended learning are adopted to complement the drawbacks of e-learning these days. One of the common purposes for adopting these tools is to enhance the interaction level by using bbs or blogs based on e-communities. If the cooperative learning contents management tools that share learners' knowledge in e-learning are provided, interactivity and educational effects can be enhanced. In this paper, a tree-based learning contents construction tool and a community-based cooperative learning contents construction tools that can share the learners' knowledge are proposed. Also, we analyze the influencing factors to the learners by using the proposed tools.