• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.2
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• pp.187-194
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• 2014

In this paper, we analyze the outage probability of macro diversity combining in cellular networks in consideration of aggregate interference from other mobile stations (MSs). Different from existing works analyzing the outage probability of macro diversity combining, we focus on a diversity gain attained by selecting a base station (BS) subject to relatively low aggregate interference. In our model, MSs are randomly located according to a Poisson point process. The outage probability is analyzed by approximating the multivariate distribution of aggregate interferences on multiple BSs by a multivariate lognormal distribution.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.4
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• pp.687-697
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• 2023

Botnets, whose attack patterns are becoming more sophisticated and diverse, are recognized as one of the most serious cybersecurity threats today. This paper revisits the experimental results of botnet detection using autoencoder, a semi-supervised deep learning model, for UGR and CTU-13 data sets. To prepare the input vectors of autoencoder, we create data points by grouping the NetFlow records into sliding windows based on source IP address and aggregating them to form features. In particular, we discover a simple power-law; that is the number of data points that have some flow-degree is proportional to the number of NetFlow records aggregated in them. Moreover, we show that our power-law fits the real data very well resulting in correlation coefficients of 97% or higher. We also show that this power-law has an impact on the learning of autoencoder and, as a result, influences the performance of botnet detection. Furthermore, we evaluate the performance of autoencoder using the area under the Receiver Operating Characteristic (ROC) curve.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.04a
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• pp.375-378
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• 2014

본 논문은 인터넷에서 주민등록번호가 유출 또는 도용되고 있는 문제점을 해결하기 위해 인터넷 사업자에게 이용자의 중복가입을 확인할 수 있는 방법 DI(Duplicated Information) 와 사업자간 동일 사용자를 식별하는 방법 CI(Connecting Information)을 제안한다. 인터넷 사업자가 이용자의 인터넷 사이트에 중복으로 가입하는 것을 확인 할 수 있는 정보를 제공하기 위한 중복 가입확인 정보 메시지 형식 규정을 제안하고, 인터넷 사업자가 타 인터넷 사업자와 연계 정보, 포인트 적립 등 제휴 서비스를 제공하기 위해 동일 이용자를 식별 할 수 있도록 연계 정보 메시지 형식 규격을 제안한다. 이용자의 개인 정보를 보호하는 수단을 제공하고 인터넷 사업자에게는 이용자의 유일성을 확인할 수 있는 수단을 제공할 것이다.

• Review of KIISC
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• v.33 no.5
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• pp.25-38
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• 2023

중요 데이터와 서비스를 격리하여 보호하기 위한 신뢰연산기술이 모바일 기기에서 널리 활용되고 있다. 신뢰연산기술은 보통 하드웨어 기반 접근제어를 통해 메모리, 레지스터, 캐시 등의 하드웨어 자원을 공격자로부터 격리하는 신뢰실행영역을 시스템 내에 생성할 수 있게 한다. 하지만 보호 대상 소프트웨어에 악용 가능한 취약점이 존재할 경우 그 보안성이 파훼될 수 있다. 따라서 신뢰실행영역 내에도 소프트웨어에 대한 공격 효율성을 최소화할 수 있는 보안 기술이 적용되어야 한다. 모바일 디바이스에 주로 적용된 ARM 아키텍처에서도 포인터 인증, 메모리 태깅과 같은 다양한 하드웨어 기반 보안기술들이 정의되고 있으며 최신 고사양 모바일 디바이스를 중심으로 적용되고 있다. 하지만 아키텍처 버전에 따라 가용한 하드웨어 보안 기술이 상이하기 때문에 보안기술의 범용성을 향상시키기 위한 방안 또한 중요하게 연구되어야 한다. 본고에서는 모바일 신뢰연산기술의 보안성을 향상시키기 위한 대표적인 범용 보안 기술들에 대해 소개한다. 특히 유저서비스, 운영체제, 하이퍼바이저의 보안성을 향상시키기 위해 제안된 디버깅 와치포인트 기반 보안 기술들에 대해 분석하고 그 한계와 타 아키텍처 확장 가능성에 대해서 논의한다.

• Journal of Korean Society for Geospatial Information Science
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• v.20 no.2
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• pp.63-71
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• 2012

Recently, web portals have been offering georeferenced SLI(Street-Level Imagery) services, such as Google Streetview. The SLI has a distinctive strength over aerial images or vector maps because it gives us the same view as we see the real world on the street. Based on the characteristic, applicability of the SLI can be increased substantially through conflation with other spatial datasets. However, spatial inconsistency between different datasets is the main reason to decrease the quality of conflation when conflating them. Therefore, this research aims to remove the spatial inconsistency to conflate an SLI with a widely used 2D vector map. The removal of the spatial inconsistency is conducted through three sub-processes of (1) road intersection matching between the SLI trace and the road layer of the vector map for detecting CPPs(Control Point Pairs), (2) inaccurate CPPs filtering by analyzing the trend of the CPPs, and (3) local alignment using accurate CPPs. In addition, we propose an evaluation method suitable for conflation result including an SLI, and verify the effect of the removal of the spatial inconsistency.

• Journal of Convergence for Information Technology
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• v.11 no.8
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• pp.36-41
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• 2021

Although the technology for prediction or analysis using artificial intelligence is constantly developing, a black-box problem does not interpret the decision-making process. Therefore, the decision process of the AI model can not be interpreted from the user's point of view, which leads to unreliable results. We investigated the problems of artificial intelligence and explainable artificial intelligence using Blockchain to solve them. Data from the decision-making process of artificial intelligence models, which can be explained with Blockchain, are stored in Blockchain with time stamps, among other things. Blockchain provides anti-counterfeiting of the stored data, and due to the nature of Blockchain, it allows free access to data such as decision processes stored in blocks. The difficulty of creating explainable artificial intelligence models is a large part of the complexity of existing models. Therefore, using the point cloud to increase the efficiency of 3D data processing and the processing procedures will shorten the decision-making process to facilitate an explainable artificial intelligence model. To solve the oracle problem, which may lead to data falsification or corruption when storing data in the Blockchain, a blockchain artificial intelligence problem was solved by proposing a blockchain-based explainable artificial intelligence model that passes through an intermediary in the storage process.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.313-315
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• 2010

In this paper, we describe research results of developing hardware rasterizer that is applicable to mobile 3D graphics system, designed in SIMD architecture and verified in FPGA. Tile-based scan conversion unit is designed like SIMD architecture running four tiles simultaneously and each tile traverses pixels hierarchical in 3-level so that visiting counts is minimized. As experimental results, $8{\times}8$ is the most efficient size of tile and the last step of tile traversing is performed on $2{\times}2$ sized subtile. The rasterizer supports flat shading and gouraud shading and texture mapper supports affine mapping and perspective corrected mapping. Also, texture mapper supports point sampling mode and bilinear interpolating sampling mode and two types of wrapping modes and various blending modes. The rasterzer operates as 120Mhz on xilinx vertex4 $l{\times}100$ device. To easy verification, texture memory and frame buffer are generated as block rom and block ram.

• Journal of Korea Game Society
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• v.15 no.6
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• pp.131-140
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• 2015

The character is one of most important interest-element in role playing game genres since it shows the individuality. In general cases, game players allocate points to talent clauses that they choose. However, it is not easy to provide the suitable character-growing to players in generic system since the cases are too simple and based on just humans choices. In this paper, we propose the character growing system based on the player type inference module. Growth morphology is determined by player's behavior or type. The determination is based on petri-net. Our experimental results and analysis show that our proposed approach is suitable for character-growing system.

• Journal of Platform Technology
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• v.11 no.1
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• pp.52-59
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• 2023

The importance of spatio-temporal trajectories for contact tracing has increased due to the recent COVID-19 pandemic. Spatio-temporal trajectories store time and spatial data of moving objects. In this paper, I propose query processing for spatio-temporal trajectories of moving objects. The spatio-temporal trajectory model of moving objects has point type spatial data for storing locations and timestamp type temporal data for time. A trajectory query is a query to search for pairs of users who have been in close contact by boarding the same bus. To process the trajectory query, I use the Geolife dataset provided by Microsoft. The proposed trajectory query processing method divides trajectory data by date and checks whether users' trajectories were nearby for each date to generate information about contacts as the result.

• Journal of Internet Computing and Services
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• v.16 no.3
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• pp.59-69
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• 2015

Many users visit websites every day to perform information retrieval, shopping, and community activities. On the other hand, there is intense competition among sites which attempt to profit from the Internet users. Thus, the owners or marketing officers of each site try to design a variety of marketing strategies including cooperation with other sites. Through such cooperation, a site can share customers' information, mileage points, and hyperlinks with other sites. To create effective cooperation, it is crucial to choose an appropriate partner site that may have many potential customers. Unfortunately, it is exceedingly difficult to identify such an appropriate partner among the vast number of sites. In this paper, therefore, we devise a new methodology for recommending appropriate partner sites to each site. For this purpose, we perform site clustering from the perspective of visitors' similarities, and then identify a group of sites that has a number of common customers. We then analyze the potential for the practical use of the proposed methodology through its application to approximately 140 million actual site browsing histories.