• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.6
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• pp.69-78
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• 2004

During the last decade, security models have been defined for two- and three-parity key exchange protocols. Currently there is a growing research interest in security models for group key management schemes. While various security models and provably secure protocols have been proposed for distributed group key exchange schemes, no results are hewn for centralized group key distribution schemes in spite of their theoretical and practical importance. We describe security requirements and a formal security model for centralized group key distribution scheme: we define the model on the channel controlled by adversaries with the ability of strong user corruption. In the security model, we propose a conversion module which can transform centralized tree-based group key distribution schemes in the literature to provably secure centralized tree-based group key distribution schemes.

• Convergence Security Journal
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• v.8 no.1
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• pp.143-152
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• 2008

Sensor networks have a wide spectrum of military and civil applications, particularly with respect to security and secure keys for encryption and authentication. This thesis presents a new centralized approach which focuses on the group key distribution with revocation capability for Wireless Sensor Networks. We propose a new personal key share distribution. When utilized, this approach proves to be secure against k-number of illegitimate colluding nodes. In contrast to related approaches, our scheme can overcome the security shortcomings while keeping the small overhead requirements per node. It will be shown that our scheme is unconditionally secure and achieves both forward secrecy and backward secrecy. The analysis is demonstrated in terms of communication and storage overheads.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.7C
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• pp.733-742
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• 2003

Unlikely unicast transmission, there are many elements that threaten security. Thus, key management of creating and distributing group keys to authorized group members is a critical aspect of secure multicast operations. To offer security in multicast environment, the recent researches are related to most group key distribution. In this thesis, we propose a group key management protocol for efficient, scalable, and multicast operation. This proposed protocol architecture can distribute traffic centralized to the key server. since the group key rekeyed by sub-group manager. The detailed simulation compared with other group key management protocol show that the proposed group key management protocol is better for join, leave, and data latency.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.30 no.1
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• pp.17-25
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• 2019

Objectives: We aimed to compare the differences in parenting stress, parenting attitudes, and parents' mental health between different adult attachment styles. Methods: Forty-four parents who completed a parental education program were enrolled in our study. They completed the Korean version of the Experience of Close Relationship Revised, Korean-Parenting Stress Index-Short Form, Maternal Behavior Research Instrument, and Symptom Checklist-90-Revised. Results: The avoidant attachment score positively correlated with parenting stress. The anxious attachment score showed a positive relationship with parenting stress, hostile parenting attitude, and psychopathology, but a negative association with an affectionate parenting attitude. The secure attachment group exhibited a more autonomous, affectionate parenting style and a less hostile parenting attitude and less parenting stress than the insecure attachment group. Dismissing-avoidant attachment parents reported significantly higher parenting stress scores than secure attachment parents. Preoccupied and fearful-avoidant attachment parents displayed a more hostile parenting style than secure attachment parents. Dismissing-avoidant and preoccupied parents reported a less affectionate parenting attitude than secure attachment parents. Conclusion: There were differences in parenting stress, parenting attitudes, and parents' mental health depending on the adult attachment style. More specific education and interventions based on parental attachment type are necessary for parents.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.5
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• pp.1450-1470
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• 2023

In a Vehicular Cloud (VC) network, an announcement protocol plays a critical role in promoting safety and efficiency by enabling vehicles to disseminate safety-related messages. The reliability of message exchange is essential for improving traffic safety and road conditions. However, verifying the message authenticity could lead to the potential compromise of vehicle privacy, presenting a significant security challenge in the VC network. In contrast, if any misbehavior occurs, the accountable vehicle must be identifiable and removed from the network to ensure public safety. Addressing this conflict between message reliability and privacy requires a secure protocol that satisfies accountability properties while preserving user privacy. This paper presents a novel announcement protocol for secure communication in VC networks that utilizes group signature to achieve seemingly contradictory goals of reliability, privacy, and accountability. We have developed the first comprehensive announcement protocol for VC using group signature, which has been shown to improve the performance efficiency and feasibility of the VC network through performance analysis and simulation results.

• Journal of KIISE:Information Networking
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• v.36 no.5
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• pp.437-455
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• 2009

In the near future, various multicast based services will be provided over clustered wireless networks. To provide multicast services in secure manner, multicast messages are encrypted by using group key which is shared by group members. Therefore, various group key management schemes have been introduced until now. Among them, tree based approach is one of the most representative paradigms in group key management. Traditional tree based approaches effectively reduce rekeying message transmissions of the key distribution center. However, they do not consider the network bandwidth used for transmitting the rekeying messages. In this paper, we firstly present formulas that describe bandwidth consumption of tree based group key management scheme. Based on our formulations, we propose a bandwidth efficient key tree management scheme for clustered wireless networks where membership changes occur frequently. Simulation results show that our scheme effectively reduces the bandwidth consumption used for rekeying compared to existing key tree schemes.

• Journal of the Korean Society of Food Culture
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• v.36 no.5
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• pp.455-463
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• 2021

This study was conducted to examine the status of food consumption and nutrition intake of young adults according to food security using data from the Korea National Health and Nutrition Examination Survey (KNHANES) (2008~2018). A total of 10,655 young adults aged 19~34 years participated in the study. The subjects in the moderately/severely food insecure group consumed less fruits, vegetables, meat, nuts and seeds than those in food secure/mildly food insecure group after adjusting for confounding factors. The moderately/severely food insecure group significantly decreased mean adequacy ratio (MAR) and nutrient adequacy ratio (NAR) for protein, vitamin A, riboflavin, niacin, vitamin C, calcium, phosphorus and iron compared to the food secure/ mildly food insecure group. The percentages of the participants consuming a daily diet with carbohydrate, protein, vitamin A, thiamin, riboflavin, niacin, vitamin C, phosphorus and iron less than the estimated average requirement (EAR) increased in the moderately/severely food insecure group compared with the food secure group. This study suggested that the nutrition intake of young adults was related to food security status. These findings can be used as basic data for developing nutritional policies for young adults.

• Convergence Security Journal
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• v.16 no.7
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• pp.121-127
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• 2016

Recently, the popularity of smart devices such as Wi-Fi and LTE has increased the use ratio of wireless dramatically. On the other hand, the use ratio of wired internet is decreasing. The IoT(Internet of Things) is not only for people but also for communication between people and things, and communication between things and things by connecting to a wireless without choosing a place. Along with the rapid spread of the IoT there is a growing concern about the threat of IoT security. In this paper, the proposed scheme is a efficiency group key agreement in IoT environment that guarantees secure communication among light-weight devices. The proposed scheme securely be able to communication with the group devices who share a group key, generated by own secret value and the public value. Such property is suitable to the environment which are required a local area and a group.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.8
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• pp.2042-2060
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• 2013

In wireless sensor networks (WSNs), energy efficiency is one of the most essential design considerations, since sensor nodes are resource constrained. Group communication can reduce WSNs communication overhead by sending a message to multiple nodes in one packet. In this paper, in order to simultaneously resolve the transmission security and scalability in WSNs group communications, we propose a hierarchical cluster-based secure and scalable group key management scheme, called HRKT, based on logic key tree and route key tree structure. The HRKT scheme divides the group key into cluster head key and cluster key. The cluster head generates a route key tree according to the route topology of the cluster. This hierarchical key structure facilitates local secure communications taking advantage of the fact that the nodes at a contiguous place usually communicate with each other more frequently. In HRKT scheme, the key updates are confined in a cluster, so the cost of the key updates is reduced efficiently, especially in the case of massive membership changes. The security analysis shows that the HRKT scheme meets the requirements of group communication. In addition, performance simulation results also demonstrate its efficiency in terms of low storage and flexibility when membership changes massively.

• Korean Journal of Child Studies
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• v.26 no.6
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• pp.89-110
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• 2005

Subjects were 66 3- to 4-year-old-Children of unemployed mothers from upper middle class families. Attachment behaviors were measured with the Preschool Strange Situation(Cassidy and Marvin, 1992) and classified as secure, avoidant, dependent, or disorganized. Narrative representations of mothers by Children were obtained by video taped interviews using the MacArthur Story-Stem Battery and coded by the MacArthur Narrative Working Group(1997) system. Data were analyzed with descriptive statistics and t test. Results were that children in the secure group showed more positive representations of their mothers, more prosocial story themes, had higher scores in theme coherence and showed more positive emotional expression than those in the insecure group. The attachment behaviors of the 4 groups(A, B, C, D) were closely correlated with the attachment representations shown in MSSB.