• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.11
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• pp.1511-1517
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• 2018

Mobile Device-to-Device (D2D) caching networks can transmit multimedia data to users directly without passing through any network infrastructure by storing popular multimedia contents in advance that are popular among many mobile users at caching server devices (CSDs) in distributed manners. Thus, mobile D2D caching networks can significantly reduce backhaul traffic in wired networks and service latency time of mobile users. In this paper, we propose an efficient transmission scheme that can enhance the transmission efficiency of mobile D2D caching networks by using multiple CSDs that are caching the contents that are popular among mobile users. By sorting the multiple CSDs that are caching a content that mobile users want to receive according to their channel gains, the proposed scheme can reduce the complexity of algorithm significantly, compared to an optimal scheme based on Brute-force searching, and can also obtain much higher network transmission efficiency than the existing Blanket and Opportunistic transmission schemes.

• Journal of Internet Computing and Services
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• v.20 no.5
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• pp.9-18
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• 2019

Android Application Package (APK) is vulnerable to repackaging attacks. Therefore, obfuscation technology was applied inside the Android APK file to cope with repackaging attack. However, as more advanced reverse engineering techniques continue to be developed, fake Android APK files to be released. A new approach is needed to solve this problem. A blockchain is a continuously growing list of records, called blocks, which are linked and secured using cryptography. Each block typically contains a cryptographic hash of theprevious block, a timestamp and transaction data. Once recorded, the data inany given block cannot be altered retroactively without the alteration of all subsequent blocks. Therefore, it is possible to check whether or not theAndroid Mobile APK is forged by applying the blockchain technology. In this paper, we construct a discrimination DApp (Decentralized Application) against forgery Android Mobile APK by recording and maintaining the legitimate APK in the consortium blockchain framework like Hyperledger Fabric by Composer. With proposed DApp, we can prevent the forgery and modification of the appfrom being installed on the user's Smartphone, and normal and legitimate apps will be widely used.

• Journal of Digital Convergence
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• v.19 no.6
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• pp.355-362
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• 2021

This study was attempted to examine the effectiveness of mobile-based military WithYou programs. The research design was a quasi-experimental study with one group pretest-posttest design. Data were collected from 17 December to 23 December 2020. 42 and 37 members of the Air base in City C participated in the pretest and posttest, respectively. A video education program developed to inspire bystander intervention efficacy and the intention of helping peers and strangers was provided on mobile. The data collected before and after attending the program were analyzed using descriptive statistics and t-test. The results showed that mobile-based military WithYou program was effective in increasing the intention to help friends and others. Attempts to develop and apply educational content using mobile devices for military personnel will be meaningful.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.4
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• pp.511-523
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• 2023

Research on the integration of unmanned aerial vehicles and deep learning for reinforced concrete damage detection is actively underway. Convolutional neural networks have a high impact on the performance of image classification, detection, and segmentation as backbones. The MobileNet, a pre-trained convolutional neural network, is efficient as a backbone for an unmanned aerial vehicle-based damage detection model because it can achieve sufficient accuracy with low computational complexity. Analyzing vanilla convolutional neural networks and MobileNet under various conditions, MobileNet was evaluated to have a verification accuracy 6.0~9.0% higher than vanilla convolutional neural networks with 15.9~22.9% lower computational complexity. MobileNetV2, MobileNetV3Large and MobileNetV3Small showed almost identical maximum verification accuracy, and the optimal conditions for MobileNet's reinforced concrete damage image feature extraction were analyzed to be the optimizer RMSprop, no dropout, and average pooling. The maximum validation accuracy of 75.49% for 7 types of damage detection based on MobilenetV2 derived in this study can be improved by image accumulation and continuous learning.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.5
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• pp.167-180
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• 2021

Due to the development of IT technology and the spread of infectious diseases, online non-face-to-face services are rapidly expanding. In particular, the information delivery process is also changing from the past postal branch-based to an information delivery system using mobile devices. This change is due to the change from the information delivery using the telephone line to the information delivery system using the Internet. Mobile notification service is a service that sends electronic notices to mobile devices held by users to deliver information and is validated for delivery, which has the advantage of reducing the benefits of unnecessary mail production, exposure to personal information, and misdelivery. However, user identification information must be provided to operators that provide mobile electronic notification services. In this paper, the current state of use of the mobile electronic notice service, which has been in effect since 2019, is investigated and analyzed, and the current mobile electronic notice service is to be safely provided and to take appropriate protection measures for personal information. In providing the mobile electronic notification service to users, it is possible to identify the service standards required by the sending agency, and based on this, prepare the technical standards for the mobile electronic notification service that the sending agency must comply with in advance and use it for the mobile electronic notification service.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.07a
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• pp.201-204
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• 2010

물체 인식 및 추적 기술은 기계가 영상 정보를 기반으로 주변을 인지하고 정황을 파악하는 컴퓨터 비전 분야의 매우 중요한 연구 영역 중 하나이다. 현재까지 이러한 물체 인식/추적에 대한 다양한 연구들이 있어 왔고, 최근 증강현실에 대한 높은 관심을 바탕으로 증강현실을 위한 영상 정보 기반의 정확하고 정교한 추적 기술에 대한 관심 또한 매우 높아졌다. 본 논문에서는 텍스쳐가 없는 단색의 블록에 대해 증강현실을 실현하기 위한 물체 추적 방식을 제안한다. 제안하는 방식은 다수의 블록들을 조합하여 구성하고, 이 조합으로부터 추출한 특징점에 색상 정보 기반의 지역 서술자를 정의함으로써 사전에 정의된 서술자와 의 비교를 통해 물체를 추적하는 방식이다. 제안된 추적 방식은 사전에 기준이 되는 지역 서술자를 정의함에 있어서 기준 영상에 다양한 어파인 변환을 적용함으로써 카메라와 대상물과의 각도가 큰 입력 영상에 대해서도 추적에 실패하지 않는다. 실험을 통해 제안된 방식을 집 모양으로 구성한 블록 조합에 적용하여 3차원 가상 콘텐츠를 증강시켜 봄으로써 제안된 방식의 유용성을 확인하였다. 제안된 방식은 텍스쳐가 없는 환경에서 사용자의 상호작용으로 텍스쳐를 구성하고 이를 추적하는 방식으로 향후 아이들을 위한 교육 프로그램, 모바일 기기에서의 응용 프로그램 등으로 적용 가능하다.

• Journal of Digital Contents Society
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• v.15 no.3
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• pp.357-363
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• 2014

In this paper, we propose a new audio forensic marking system for protecting the copyright of the Internet-based music streaming services. In the proposed method, in order to guarantee the QoS of the streaming service, high speed, and generates a forensic mark inserted MP3 file. We make pre-marking process and generate a new forensic marked MP3 file, a combination of the pre-marked MP3 frame, the inserted user information. Experimental results show that the proposed method satisfactory results robustness and imperceptibility, and real-time properties. In addition, we were confirmed that the real-time embedding and detection from the streaming-based audio forensic marking system that has been implemented on the server/client is possible.

• Annual Conference on Human and Language Technology
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• 2023.10a
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• pp.525-530
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• 2023

최근 소셜 네트워크 서비스(SNS) 및 모바일 서비스가 증가함에 따라 사용자들은 다양한 종류의 위험에 직면하고 있다. 특히 온라인 그루밍과 온라인 루머 같은 위험은 한 개인의 삶을 완전히 망가뜨릴 수 있을 정도로 심각한 문제로 자리 잡았다. 그러나 많은 경우 이러한 위험들을 판단하는 시점은 사건이 일어난 이후이고, 주로 법적인 증거채택을 위한 위험성 판별이 대다수이다. 따라서 본 논문은 이러한 문제를 사전에 예방하는 것에 초점을 맞추었고, 계속적으로 발생하는 대화와 같은 event를 실시간으로 감지하고, 위험을 사전에 탐지할 수 있는 Real-Time Early Risk Detection(RERD) 문제를 정의하고자 한다. 온라인 그루밍과 루머를 실시간 조기 위험 감지(RERD) 문제로 정의하고 해당 데이터셋과 평가지표를 소개한다. 또한 RERD 문제를 정확하고 신속하게 해결할 수 있는 강화학습 기반 새로운 방법론인 RT-ERD 모델을 소개한다. 해당 방법론은 RERD 문제를 이루고 있는 온라인 그루밍, 루머 도메인에 대한 실험에서 각각 기존의 모델들을 뛰어넘는 state-of-the-art의 성능을 달성하였다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.3
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• pp.17-22
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• 2018

This study suggests that 'Will not we use more smartphones while watching TV commercials? Then, will the TV advertising effect decrease due to the distributed concentration?". As a result of the preliminary study, it was confirmed that about 63% of users watching TV commercials use smartphones together. In this study, we propose the possibility of a new mobile advertising service by experimenting and analyzing the effect of high frequency technology based TV advertising linked mobile advertising service. Experimental results show that the response rate of the same content is improved about 9 times as compared with that of the general mobile advertisement when the advertisement of the same content is provided by the TV advertisement interlocking type. It can be confirmed that it is quite effective to provide the same content advertisement to the customers who are in front of the TV at the time of sending the TV advertisement. Therefore, it is expected that various services based on high frequency technology will be activated as a new advertising service that will preserve the effect of TV commercials in the future.

• Journal of Korea Multimedia Society
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• v.8 no.7
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• pp.916-923
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• 2005

In recent times, mobile phones that play an important role in voice communication have became increasingly exciting due to the ability to transmit multimedia contents. However, user's communication cost and service usage fees for digital context exchange are still prohibitive. In this paper, we consider the task of transmitting a facial image in the context of mobile avatar generation. We present image compression as a useful technique to reduce service usage costs of data exchange in mobile communications. In view of this we propose an image compression algorithm that performs better than existing techniques. The suggested algorithm in this paper uses the location of significant coefficient on the wavelet image by detecting facial region as well as the spatial correlation between decomposed bands by wavelet transformation. The algorithm perform well and archives an efficient compression ratio. The proposed method recognizes location information of significant coefficient in advance, thus it is more suitable than existing general compression methods for mobile avatar generation systems.