• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2239-2246
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• 2024

The present study aimed to assess the radioactive hazards associated with the application of granitoid rocks in building materials. An HPGe spectrometer was used to detect the levels of the radioactive elements uranium-238, thorium-232, and potassium-40 in the granitoid rocks. The results showed that the levels of these elements were lower (38.32 < 33 Bq kg^-1), comparable (47.19-45 Bq kg^-1) and higher (992.26 ≫> 412 Bq kg^-1) than the worldwide limits for ²³⁸U, ²³²Th, and ⁴⁰K concentration, respectively. The exposure to gamma radiation of granitoid rocks was studied by various radiological hazard variables like the absorbed dose rate (D_air), the outdoor and indoor annual effective dose (AED_out and AED_in), and excess lifetime cancer risk (ELCR). A variety of statistical methods, including Pearson correlation, principal component analysis (PCA), and hierarchical cluster analysis (HCA) was used, to study the relationship between the radioactive elements and the radiological hazards. According to statistical analysis, the main radioactive risk of granitoid rocks is contributed to by the elements uranium-238, thorium-232, and potassium-40. Granitoid rocks can be applied in building materials, but under control to prevent risk to the public.

• Annual Conference of KIPS
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• 2007.05a
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• pp.1225-1228
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• 2007

무선 네트워크와 모바일 기술의 발달로 무선상에서의 통신뿐만 아니라, 모바일 기기의 이동성에 대한 요구가 점점 더 커지고 있다. 모바일 기기의 이동성을 지원하기 위해Fast Mobile IPv6 (FMIPv6), Hierarchical Mobile IPv6 (HMIPv6)와 같은IPv6기반의 네트워크 계층 프로토콜이 제안되어 왔으며, 최근에는 트랜스포트 계층에서 동작하는 mobile Stream Control Transport Protocol (mSCTP) 가 제안 되었다. 네트워크 계층에서의 이동성을 지원하기 위한 방안 중 하나인 FMIPv6 의 핸드오프 과정은 엑세스 라우터간 양방향 터널링을 설정 함으로서 엑세스 라우터의 버퍼링 오버헤드가 발생하고, 터널링 과정을 위한 메시지 교환으로 인해 핸드오프 지연이 발생하게 된다. 본 논문에서는 FMIPv6 의 이러한 단점을 해결하기 위해 트랜스포트 계층의 이동성 지원 방안인 mSCTP 를 이용한 통합 핸드오프 기법을 제안한다. 양단의 세션을 유지한 채 새로운 IP 주소를 등록 할 수 있는 mSCTP 를 사용 함으로서 FMIPv6 의 터널링으로 인해서 발생하는 엑세스 라우터의 오버헤드와 핸드오프 지연 시간을 줄이고 전체적인 핸드오프 성능을 향상 시킨다.

• Journal of Korea Multimedia Society
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• v.16 no.8
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• pp.954-961
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• 2013

To enhance the efficiency of network, content-centric networking (CCN), one of future Internet architectures, allows network nodes to temporally cache transmitted contents and then to directly respond to request messages which are relevant to previously cached contents. Also, since CCN uses a hierarchical content-name, not a host identity like source/destination IP address, for request/response packet routing and CCN request message does not include requester's information for privacy protection, contents-providers/ network nodes can not identify practical requesters sending request messages. So to send back relevant contents, network nodes in CCN records both a request message and its incoming interfaces on Pending Interest Table (PIT). Then the devices refer PIT to return back a response message. If PIT is exhausted, the device can not normally handle request/response messages anymore. Hence, it is needed to detect/react attack to exhaust PIT. Hence, in this paper, we propose improved detection/reaction schemes against attacks to exhaust PIT. In practice, for fine-grained control, this proposal is applied to each incoming interface. Also, we propose the message framework to control attack traffic and evaluate the performance of our proposal.

• Convergence Security Journal
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• v.12 no.1
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• pp.35-42
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• 2012

Increase of data traffic and the advent of new real-time services require to change from the traditional TDM-based (Time Division Multiplexing) networks to the optical networks that soft and dynamic configuration. Voice and lease line services are main service area of the traditional TDM-based networks. This optical network became main infrastructure that offer many channel that can convey data, video, and voice. To provide high resilience against failures, Packet-optical networks must have an ability to maintain an acceptable level of service during network failures. Fast and resource optimized lightpath restoration strategies are urgent requirements for the near future Packet-optical networks with a Generalized Multi-Protocol Label Switching(GMPLS) control plane. The goal of this paper is to provide packet-optical network with a hierarchical multi-layer recovery in order to fast and coordinated restoration in packet-optical network/GMPLS, focusing on new implementation information. The proposed schemes do not need an extension of optical network signaling (routing) protocols for support.

• The Journal of the Korea Contents Association
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• v.16 no.8
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• pp.322-331
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• 2016

This study aims to investigate interaction effects of self-esteem with self-resilience on adolescents' anger and to suggest for teaching method. For research, Anger, self-esteem, self-resilience was measured to total of 419 adolescents. The collected data were analyzed by multiple regression analysis and hierarchical regression analysis. The results, Firstly, anger were negatively influenced by the emotion regulation, diversity of Interests and interest, self-esteem in schools. Secondly, anger-in was negatively influenced by the self-esteem in schools, self-esteem in social, emotion regulation. Thirdly, anger-control was positively influenced by the emotion regulation, self-esteem in family. Fourthly, interaction effects of the self-esteem and self-resilience was statistically confirmed on anger. Fifthly, interaction effects of the self-esteem and self-resilience was statistically confirmed on anger-control.

• Journal of Communications and Networks
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• v.18 no.5
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• pp.784-795
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• 2016

In this paper, we investigate the resource allocation problem in time-varying heterogeneous wireless networks (HetNet) with multi-homing user equipments (UE). The stochastic optimization model is employed to maximize the network utility, which is defined as the difference between the HetNet's throughput and the total energy consumption cost. In harmony with the hierarchical architecture of HetNet, the problem of stochastic optimization of resource allocation is decomposed into two subproblems by the Lyapunov optimization theory, associated with the flow control in transport layer and the power allocation in physical (PHY) layer, respectively. For avoiding the signaling overhead, outdated dynamic information, and scalability issues, the distributed resource allocation method is developed for solving the two subproblems based on the primal-dual decomposition theory. After that, the adaptive resource allocation algorithm is developed to accommodate the timevarying wireless network only according to the current network state information, i.e. the queue state information (QSI) at radio access networks (RAN) and the channel state information (CSI) of RANs-UE links. The tradeoff between network utility and delay is derived, where the increase of delay is approximately linear in V and the increase of network utility is at the speed of 1/V with a control parameter V. Extensive simulations are presented to show the effectiveness of our proposed scheme.

• The Journal of the Korea Contents Association
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• v.17 no.11
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• pp.290-302
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• 2017

The purpose of this study was to explore the mediating effect of emotional dysregulation on the relationship between the specific domains of self-esteem and aggression. Three questionnaire were administered to 287 individuals and the multiple regression analyses and Baron and Kenny's hierarchical regression analyses were used. The result shows that social and objective ability and positive character had significant influence on aggression, while impulse control difficulties, lack of emotional clarity and limited access to emotion regulation strategies largely contributed to aggression. Moreover, emotional dysregulation functioned as a significant mediator variable for explaining the link between self-esteem and aggression. Impulse control difficulties have fully mediated positive personality and hostility, limited access to emotion regulation has partially mediated social and objective ability and hostility, respectively.

• The Journal of the Korea Contents Association
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• v.20 no.5
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• pp.389-397
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• 2020

This study analyzed 308 college students to identify how family function and satisfaction with life is related to the positive attitude of college students. SPSS Win 18.0 program was used to perform ANOVA and Hierarchical Regression Analysis. As a result, first, older students had more positive attitude compare to the younger students. Secondly, among family functions, when the family cohesion was stronger, the diversification of perspective, self acception, and social adjustment was stronger, and it was identified that the diversification of perspective, self acception, and self control was higher when the family adaptability was greater. Thirdly, when the satisfaction level of life was higher, the positive attitude was high as well. Fourth, the higher the life satisfaction, the higher the positive attitude, except for self-control, all the sub-factors.

• Journal of KIISE:Information Networking
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• v.28 no.4
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• pp.611-620
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• 2001

To meet the requirements of reliable service for various applications, a Reliable Multicast Transport Protocol should be implemented over IP Multicast where currently best-effort service is provided. Among the current researches, hierarchical tree-based mechanism has been proposed and actively studied. This mechanism is known to provide high scalability as well as reliability, but needs an additional tree configuring mechanism for building an efficient logical tree in transport layer. Bottom-up approach has been used for creating such a tree. This method has benefits from parallel tree construction for receivers, while it has some drawbacks such that it does not guarantee a loop-free tree and brings heavy message overhead during tree creation process. Therefore, this paper proposes a top-down based mechanism for constructing a control tree, which can guarantee loop-freeness by step-wise mannered tree building. From experimental simulations, it shows that the proposed mechanism has less message overhead. It is recommended that the bottom-up and the proposed top-down will be selectively used in real networks, according to the requirements of the concerned multicast applications.

• Journal of Korean Academy of Nursing Administration
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• v.21 no.3
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• pp.277-286
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• 2015

Purpose: This study was done to identify the status of smartphone addiction among nursing students and to examine the mediating effects of Internet ethics on the relationship between smartphone addiction, physical symptoms and psychological well-being. Methods: Data were collected between May 20 and June 23, 2014. Participants were a convenience sample of 214 nursing students of one university in Seoul. Structured questionnaires were used to measure degree of smartphone addiction, physical symptoms, psychological well-being and Internet ethics. Data was analyzed using Independent t-test, One-way ANOVA, Pearson correlation coefficient, multiple hierarchical regression. Results: Of the nursing students, 14.5% had high level of risk of smartphone addiction and 16.8% had potential risk. Higher frequency of physical symptoms and lower level of Internet ethics were related to the higher level of smartphone addiction. Voluntary-control in Internet ethics had mediating effects on the relationship between smartphone addiction and physical symptoms. Conclusion: The results suggest that the level of smartphone addiction may lowered in nursing students by intensifying Internet ethics especially voluntary-control. Based on these findings, Internet ethics program for nursing students should be developed to facilitate the effective use of smartphones.