• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권3호
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• pp.670-684
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• 2024

3D Cross-Modal Retrieval (3DCMR) is a task that retrieves 3D objects regardless of modalities, such as images, meshes, and point clouds. One of the most prominent methods used for 3DCMR is the Cross-Modal Center Loss Function (CLF) which applies the conventional center loss strategy for 3D cross-modal search and retrieval. Since CLF is based on center loss, the center features in CLF are also susceptible to subtle changes in hyperparameters and external inferences. For instance, performance degradation is observed when the batch size is too small. Furthermore, the Mean Squared Error (MSE) used in CLF is unable to adapt to changes in batch size and is vulnerable to data variations that occur during actual inference due to the use of simple Euclidean distance between multi-modal features. To address the problems that arise from small batch training, we propose a Noisy Center Loss (NCL) method to estimate the optimal center features. In addition, we apply the simple Siamese representation learning method (SimSiam) during optimal center feature estimation to compare projected features, making the proposed method robust to changes in batch size and variations in data. As a result, the proposed approach demonstrates improved performance in ModelNet40 dataset compared to the conventional methods.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 춘계종합학술대회
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• pp.571-574
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• 2001

무선인터넷이란 시스템의 구성에 따라 무선으로 음성, 데이터, 영상을 송ㆍ수신할 수 있는 서비스라고 할 수 있으며, 무선인터넷 산업은 정보통신 분야에서 전 세계적으로 가장 각광을 받고 있는 것 중의 하나가 되고 있다. 따라서, 세계는 무선인터넷 관련 단말기, 서비스, 인터넷망 및 솔루션 제공 등과 같은 기술개발 및 표준화에 박차를 가하고 있다. 본 고에서는 국내 무선인터넷 산업의 활성화와 경쟁력 있는 무선인터넷 서비스 제공을 위하여 각 요소별 국내외의 표준화 동향을 점검하고, 정부의 효율적인 무신인터넷 표준화 추진 정책방향을 진단해 보고자 한다.

• 전자공학회논문지 IE
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• 제47권4호
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• pp.48-52
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• 2010

Mobile Internet 개념인 WiBro Data Service는 최근 무선 데이터 통신의 규모는 스마트 폰이나 WiBro 서비스 등의 보급에 힘입어 최근 빠르게 성장하고 있다. 이에 따라 무선 인터넷 분야에서 무선구간 보안성 확보 문제와 네트워크 구간의 보안성 확보 문제 강조되고 있다. 본 논문에서는 이러한 문제에 대한 해결 방안으로 기존에 구현되어 있는 기술들을 결합하여 Public 망 개념인 WiBro Network에서 기업 가입자의 보안성 확보를 위한 Mobile-VPN구축 방법을 제안하고자 한다.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• 제29권1호
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• pp.26-30
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• 2018

Objectives: To investigate the association of problematic Internet use with oral health behaviors and oral health status in a nationally representative sample of Korean adolescents. Methods: Data from the 2010 Korea Youth Risk Behavior Web-based Survey (73238 Korean adolescents; mean age $15.06{\pm}1.75years$; age range, 12-18 years) were used. Problematic Internet use was measured using the Korean Internet Addiction Proneness Scale for Youth-Short Form. Self-report questionnaires were used to assess oral health behaviors and oral health status of adolescents. Results: Problematic Internet users were less likely to brush their teeth frequently [adjusted odds ratio (AOR)=0.59; 95% confidence interval (CI)=0.56-0.63] and at school after lunch (AOR=0.89; 95% CI=0.83-0.94) as well as more likely to perceive their oral health to be poorer (AOR=1.63, 95% CI=1.54-1.72) and experience oral symptoms (AOR=1.75, 95% CI=1.65-1.86) compared to usual Internet users. Conclusion: The study results indicate that problematic Internet use may adversely affect the oral health of Korean adolescents. Thus, oral health screening and Internet-based education are needed for adolescents experiencing problematic Internet use.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권11호
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• pp.5673-5691
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• 2019

Information centric mobile network can significantly improve the data retrieving efficiency by caching contents at mobile edge. However, the cache pollution attack can affect the data obtaining process severely by requiring unpopular contents deliberately. To tackle the problem, we design an algorithm of mitigating cache pollution attacks in information centric mobile network. Particularly, the content popularity distribution statistic is proposed to detect abnormal behavior. Then a probabilistic caching strategy based on abnormal behavior is applied to dynamically maintain the steady-state distribution for content visiting probability and achieve the purpose of defense. The experimental results show that the proposed scheme can achieve higher request hit ratio and smaller latency for false locality content pollution attack than the CacheShield approach and the baseline approach where no mitigation approach is applied.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권7호
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• pp.1610-1623
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• 2013

In-network caching is a key component of information-centric networking (ICN) for reducing content download time, network traffic, and server workload. Data center network (DCN) is an ideal candidate for applying the ICN design principles. In this paper, we have evaluated the effectiveness of caching placement and replacement in DCN with butterfly-topology. We also suggest a new cache placement policy based on the number of routing nodes (i.e., hop counts) through which travels the content. With a probability inversely proportional to the hop counts, the caching placement policy makes each routing node to cache content chunks. Simulation results lead us to conclude (i) cache placement policy is more effective for cache performance than cache replacement, (ii) the suggested cache placement policy has better caching performance for butterfly-type DCNs than the traditional caching placement policies such as ALWASYS and FIX(P), and (iii) high cache hit ratio does not always imply low average hop counts.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권3호
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• pp.1164-1183
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• 2019

The rapid development of cloud computing and high requirements of operators requires strong support from the underlying Data Center Networks. Therefore, the effectiveness of using resources in the data center networks becomes a point of concern for operators and material for research. In this paper, we discuss the online virtual-cluster provision problem for multiple tenants with an aim to decide when and where the virtual cluster should be placed in a data center network. Our objective is maximizing the total revenue for the data center networks under the constraints. In order to solve this problem, this paper divides it into two parts: online multi-tenancy scheduling and virtual cluster placement. The first part aims to determine the scheduling orders for the multiple tenants, and the second part aims to determine the locations of virtual machines. We first approach the problem by using the variational inequality model and discuss the existence of the optimal solution. After that, we prove that provisioning virtual clusters for a multi-tenant data center network that maximizes revenue is NP-hard. Due to the complexity of this problem, an efficient heuristic algorithm OMS (Online Multi-tenancy Scheduling) is proposed to solve the online multi-tenancy scheduling problem. We further explore the virtual cluster placement problem based on the OMS and propose a novel algorithm during the virtual machine placement. We evaluate our algorithms through a series of simulations, and the simulations results demonstrate that OMS can significantly increase the efficiency and total revenue for the data centers.

• 융합보안논문지
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• 제11권4호
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• pp.11-17
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• 2011

본 논문에서는 IDC를 기반으로 한 FLV 동영상 솔루션을 Mini IPTV에 적용한 시스템 설계 및 구현을 제안한다. IDC의 에너지를 최소화하고, 자원 활용을 극대화시키는 Green Data Center로 설계하며, Mini IPTV의 다양한 콘텐츠를 서비스 공급자 및 네트워크 공급자가 네트워크를 통해 Mini IPTV 가입자에게 제공한다. 이때 FLV 솔루션 파일 포맷과 압축 기술을 이용해 동영상의 화질과 압축률을 개선하도록 구현함으로써, 트래픽 비용의 절감 및 보안 문제를 해결하고, 특히 웹에서 급속히 팽창하고 있는 e-Learning 분야에 활용하고자 한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권12호
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• pp.5669-5684
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• 2018

The new mobile edge network architecture has been required for an increasing amount of traffic, quality requirements, advanced driver assistance system for autonomous driving and new cloud computing demands on highway. This article proposes a hierarchical cloud computing architecture to enhance performance by using adaptive data load distribution for buses that play the role of edge computing server. A vehicular dynamic cloud is based on wireless architecture including Wireless Local Area Network and Long Term Evolution Advanced communication is used for data transmission between moving buses and cars. The main advantages of the proposed architecture include both a reduction of data loading for top layer cloud server and effective data distribution on traffic jam highway where moving vehicles require video on demand (VOD) services from server. Through the description of real environment based on NS-2 network simulation, we conducted experiments to validate the proposed new architecture. Moreover, we show the feasibility and effectiveness for the connected car media service on highway.

• 융합보안논문지
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• 제12권3호
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• pp.93-97
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• 2012

본 논문에서는 FLV를 적용한 차세대 인터넷 방송 솔루션을 설계 및 구현하였다. 현재 현장에서 방송중인 HD급 영상을 실시간으로 압축하여 인터넷 생방송은 물론 VOD 서비스가 가능한 시스템으로 온라인을 통해 인터넷 LIVE 방송 및 VOD 서비스 그리고 UCC 서비스를 손쉽게 운영할 수 있도록 지원하는 솔루션이다. 카메라 및 VOD 영상을 H264코덱을 사용하여 실시간으로 압축하여 MPEC4, WMV 등의 영상을 인터넷 및 스마트폰에 실시간 스트리밍으로 지원하는 시스템으로 첫째, 카메라 영상의 실시간 녹화기능을 갖춘 국내 최초의 실시간 인코더 시스템(Real time encoder system)이며, Web 및 스마트폰 환경에 적합한 최신의 코덱 기술을 지원하며, 소프트웨어 제품이다. 둘째, 동영상을 MP4 플레이어로 재생이 가능하며, 사용자 채팅 및 커스터 마이징(customizing)이 가능한 양방향 인터넷 방송 시스템이다. 셋째, CMS(Contents Management System) 기능은 동영상 콘텐츠 및 강좌 관리 콘텐츠를 안드로이드 폰 및 아이폰을 통해 실시간으로 스트리밍 서비스가 가능하다.