• 한국통신학회논문지
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• 제29권8B호
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• pp.755-761
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• 2004

본 논문은 무선랜 기술을 활용한 초고속 무선인터넷 서비스에서 사용자 인증방식에 사용되는 프로토콜의 설계와 구현에 관한 것이다. IEEE 802.l1b를 기반으로 한 공중 무선랜 서비스는 최근 고속 무선 인터넷 접속 솔루션으로써 각광받고 있다. 공중 무선랜 환경에서는 특히 중앙 집중화된 인증방법과 향상된 보안대책이 필요하며 사용자 단말의 이동 시 로밍에 대한 보장이 요구된다. 본 논문에서는 IEEE 802.1x에 기반의 사용자 인증보안 기능을 설계하고 방법과 실제 임베디드 리눅스를 기반으로 한 무선랜 Access Point(AP)에서 구현하여 동작을 시험하였으며. 로밍 시 필요한 IAPP 절차에 대하여 검토하였다. 또한 업체를 통한 상용화를 진행하며, KT 네스팟 인증시스템과 정상적인 연동기능 및 관리기능이 동작함을 확인하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권9호
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• pp.2573-2589
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• 2023

As 5G mobile systems carry multiple services and applications, numerous user, and application types with varying quality of service requirements inside a single physical network infrastructure are the primary problem in constructing 5G networks. Radio Access Network (RAN) slicing is introduced as a way to solve these challenges. This research focuses on optimizing RAN slices within a singular physical cell for vehicle-to-everything (V2X) and enhanced mobile broadband (eMBB) UEs, highlighting the importance of adept resource management and allocation for the evolving landscape of 5G services. We put forth two unique strategies: one being offline network slicing, also referred to as standard network slicing, and the other being Online reinforcement learning (RL) network slicing. Both strategies aim to maximize network efficiency by gathering network model characteristics and augmenting radio resources for eMBB and V2X UEs. When compared to traditional network slicing, RL network slicing shows greater performance in the allocation and utilization of UE resources. These steps are taken to adapt to fluctuating traffic loads using RL strategies, with the ultimate objective of bolstering the efficiency of generic 5G services.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권8호
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• pp.2298-2315
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• 2024

This paper introduces a method aimed at diagnosing the presence or absence of lesions by detecting anomalies in Chest X-ray images. The proposed approach is based on the PatchCore anomaly detection method, which extracts a feature vector containing location information of an image patch from normal image data and calculates the anomaly distance from the normal vector. However, applying PatchCore directly to medical image processing presents challenges due to the possibility of diseases occurring only in specific organs and the presence of image noise unrelated to lesions. In this study, we present an image alignment method that utilizes affine transformation parameter prediction to standardize already captured X-ray images into a specific composition. Additionally, we introduce a region-specific abnormality detection method that requires affine-transformed chest X-ray images. Furthermore, we propose a method to enhance application efficiency and performance through feature map hard masking. The experimental results demonstrate that our proposed approach achieved a maximum AUROC (Area Under the Receiver Operating Characteristic) of 0.774. Compared to a previous study conducted on the same dataset, our method shows a 6.9% higher performance and improved accuracy.

• Journal of Korean Biological Nursing Science
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• 제15권4호
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• pp.173-183
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• 2013

Purpose: The purpose of this study was to compare the stress level and HPA axis activity of an internet game addiction group and non-addiction group in adolescents. Methods: A cross-sectional comparative study was performed with 140 male high school students from 9 vocational high schools at W city. Data were collected from July to September, 2012, using a questionnaire for measuring internet game addiction and stress level, blood samples for serum ACTH, and cortisol level for HPA axis activity. Data were analyzed using descriptive analysis, $X^2$-test, t-test, ANOVA, and Pearson correlation coefficient with SPSS/WIN 15.0. Results: The stress level of the internet game addicted group was significantly higher than that of the non-addicted group (p<.001). The serum cortisol level was also significantly higher in the internet game addicted group than in the non-addicted group (p<.026). The serum ACTH level was higher in the internet game addicted group more than in the non-addicted group (p<.072). Conclusion: These results showed that internet game addiction could increase stress level and HPA axis activity in high school adolescents. Thus, a nursing approach to prevent and relieve internet game addiction should be initiated to stabilize the HPA axis of internet game addicted adolescents.

• 한국의류학회지
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• 제31권3호
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• pp.410-419
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• 2007

The purposes of this study were to segment consumers by on-line word of month and to find the differences among the segmented groups in regard to fashion involvement, internet perceived risk, and internet purchase behavior. The subjects of this study were female consumers who were members of online cafe in Korea. The data were collected during October, 2004. The respondents returned the questionnaires through internet and 480 questionnaires were finally used in the data analysis. The statistical analyses used for the study were factor analysis, cluster analysis, t-test, and $X^2-test$. The results showed that word-of·mouth communication on internet(e-WOM) is composed of two factors, word-of-mouth transmission and word-of-mouth acceptance. These two factors were put under cluster analysis and were classified into two groups of the word-of·mouth communication: WOM group and non-WOM group. T-test showed that word-of-mouth communication groups were significantly different in regard to fashion involvement, internet perceived risk, and internet purchase behavior. For example, WOM group was more uncertain of their clothing choices, put more weight on the internal factors of clothing selection, and was a frequent purchaser of internet fashion products. Internet fashion business needs to implement the proper marketing strategies based on the results of the study.

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2006년도 공동심포지엄
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• pp.162-186
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• 2006

• 중국학논총
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• 제71호
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• pp.41-59
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• 2021

With the progress of social economy and science and technology, network media technology has developed rapidly, China has ushered in the network information age, and the network buzzwords emerged to reflect the interaction and influence between language and society. The network buzzwords of "X+ ren "indirectly show the social psychology and value orientation of modern people with their unique structural characteristics, semantic connotation and cultural deposits, and so on. Based on this, we have conducted a multi-angle investigation on the network buzzwords "X+ ren". This paper first analyzes the structure types and syntactic functions of the lexical model of "X+ ren ", then makes a semantic analysis of the lexical model of "X+ Ren ", and finally investigates the causes and influences of the popularity of "X+ ren ". Through the investigation, we believe that "X+ ren "will continue to grow, and "X+ ren" will continue to attract the attention of the academic community.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2007년도 추계 종합학술대회 논문집
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• pp.591-594
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• 2007

X-Internet과 X-Forms 기반의 웹 UI 개발 툴로 개발되어 클라이언트 상에서 운영되는 소프트웨어 대한 테스트 프로세스를 제안하고 사이트를 구축한다. 이러한 소프트웨어는 개발이 완료되어 운영되는 과정에도 사용자의 요구, 성능 향상, 기능 개선, 기능 추가 등의 이유로 변경이 된다. 변경된 소프트웨어를 테스트하기 위해 V-모델을 확장, 변형한 테스트 프로세스를 제안한다. 제안한 테스트 프로세스는 테스트 목표와 그 목표를 달성하기 위한 활동을 정의하는 테스트 계획을 시작으로, 테스트 케이스와 데이터를 식별하고 환경을 구축하는 분석과 설계, 테스트 케이스를 명세화하고 테스트 방법론을 적용하는 구현과 실현, 리포팅과 산출물을 정리하는 테스트 마감 단계로 진행된다. 본 논문은 테스트 프로세스를 효율적으로 관리하고 기록하여 시간과 비용을 절감할 수 있는 사이트를 구축한다.

• 한국인터넷방송통신학회논문지
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• 제13권2호
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• pp.33-39
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• 2013

본 논문에서는 시스템에서 사용 가능한 자계면 T-접합 구조를 갖는 X/Ku 밴드 도파고나 다이플렉서를 설계하고 특성을 확인하였다. 본 논문에서는 시스템에서 사용 가능한 자계면 T-접합 구조를 갖는 X/Ku 밴드 도파관 다이플렉서를 설계하고 특성을 확인하였다. 설계된 다이플렉서는 X 밴드(7.25 ~ 8.4 GHz) 주파수와 Ku 밴드(12.25 ~ 14.5 GHz) 주파수를 분리시키도록 설계하였다. 일반적인 다이플렉서는 저역통과필터와 고역통과필터, 그리고 도파관 접합부로 결합된다. 그러나 본 논문에서는 저역통과필터를 사용하지 않고 고역통과필터 자계면에 임피던스를 매칭시켜 도파관을 접합함으로써 다이플렉서 구조를 간소화 하였다. 또한, 직교모드 변환기 특성을 갖는 다이플렉서를 설계하여 수직 및 수평편파를 사용할 수 있게 하였다. 본 논문에서 설계한 다이플렉서는 이중대역 및 이중편파를 만족하는 것으로 위성통신용 안테나 피드 시스템에 사용 가능하리라 생각된다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권8호
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• pp.2253-2280
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• 2024

In the upcoming era of transportation, a groundbreaking technology, known as vehicle-to-everything (V2X) communication, is poised to redefine our driving experience and revolutionize traffic management. Real-time and secure communication plays a pivotal role in V2X networks, with the decision-making process being a key factor in establishing communication and determining malicious nodes. The proposed framework utilizes a directed acyclic graph (DAG) to facilitate real-time processing and expedite decision-making. This innovative approach ensures seamless connectivity among vehicles, the surrounding infrastructure, and various entities. To enhance communication efficiency, the entire roadside unit (RSU) region can be subdivided into various sub-regions, allowing RSUs to monitor and govern each sub-region. This strategic approach significantly reduces transaction approval time, thereby improving real-time communication. The framework incorporates a consensus mechanism to ensure robust security, even in the presence of malicious nodes. Recognizing the dynamic nature of V2X networks, the addition and removal of nodes are aligned. Communication latency is minimized through the deployment of computational resources near the data source and leveraging edge computing. This feature provides invaluable recommendations during critical situations that demand swift decision-making. The proposed architecture is further validated using the "veins" simulation tool. Simulation results demonstrate a remarkable success rate exceeding 95%, coupled with a significantly reduced consensus time compared to prevailing methodologies. This comprehensive approach not only addresses the evolving requirements of secure V2X communication but also substantiates practical success through simulation, laying the foundation for a transformative era in transportation.