• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.22-24
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• 2005

이동 컴퓨팅 환경에서 통신 네트워크가 갖는 무선 채널 대역폭의 협소함과 이동 단말기의 에너지 제약으로 인해, 다수의 이동 클라이언트들에게 데이터를 전달할 때에는 다수의 클라이언트들의 동시 데이터 접근을 지원하는 브로드캐스트 방법을 사용함으로써 제약점들을 보완할 수 있다. 본 논문에서는 클라이언트의 에너지와 데이터에 대한 접근시간(access time)의 효율을 높이기 위해 데이터의 접근빈도(access frequency)를 고려한 브로드캐스트 방법과 브로드캐스트 인덱스를 추가하는 방법을 함께 반영한 OAF(Data Access Frequencies)브로드캐스팅 기법을 제안한다. DAF브로드캐스팅 기법은 데이터의 접근빈도를 고려한 인덱스를 교차하여 추가함으로써 접근빈도가 높은 데이터를 원하는 다수의 사용자에 대한 접근시간을 줄임으로써 모든 사용자의 평균 접근시간을 줄이는데 목적이 있다. 수학적 분석을 통해 DAF브로드캐스팅 기법을 평가하고 기존의 브로드캐스트 방법과 DAF브로드캐스팅 기법의 성능을 비교 분석한다.

• Journal of the Korea Society of Computer and Information
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• v.27 no.9
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• pp.131-138
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• 2022

In this paper, we propose an FA-RBAC (FA-RBAC) model based on flexible properties. This model is assigned attribute-role-centric, making it easy to manage objects, as efficient as access control, and as the network environment changes, it can provide flexible access control. In addition, fine-grained permissions and simple access control can be achieved while balancing the advantages and disadvantages of the RBAC and ABAC models, reducing the number of access control rules by combining static attribute-based roles and dynamic attribute-based rules, and verifying the validity and performance benefits of the proposed model through comparison analysis and simulation.

• ETRI Journal
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• v.45 no.5
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• pp.874-886
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• 2023

A joint resource-optimization scheme is investigated for nonorthogonal multiple access (NOMA)-enhanced scalable video coding (SVC) multicast in unmanned aerial vehicle (UAV)-assisted radio-access networks (RANs). This scheme allows a ground base station and UAVs to simultaneously multicast successive video layers in SVC with successive interference cancellation in NOMA. A video quality-maximization problem is formulated as a mixed-integer nonlinear programming problem to determine the UAV deployment and association, RAN spectrum allocation for multicast groups, and UAV transmit power. The optimization problem is decoupled into the UAV deployment-association, spectrum-partition, and UAV transmit-power-control subproblems. A heuristic strategy is designed to determine the UAV deployment and association patterns. An upgraded knapsack algorithm is developed to solve spectrum partition, followed by fast UAV power fine-tuning to further boost the performance. The simulation results confirm that the proposed scheme improves the average peak signal-to-noise ratio, aggregate videoreception rate, and spectrum utilization over various baselines.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.1201-1204
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• 2005

Whereas conveniences deriving from the development of information and telecommunication technology increase, information outflow and illegal data use are also rapidly on the rise. Consequently, many studies to prevent illegal information outflow are currently under way, and the use of Smart Card is in steep jump. Recently, Java Card is diffused fast as an alternative to complement the technical problems of the Smart Card. This paper designed and materialized the system for multi-users authentication and file access control by user through designing a Java Card applet that is used for information protection and in various application fields. For allowing a file access competence, each user's file access competence is processed via drawing up the access condition table in the applet. Therefore, illegal correction, exposure and destruction of information, which become the concerns when multi-users have an access, can be prevented. In addition, its application becomes possible in the system requiring multi-users certifications.

• Journal of the Korea Society of Computer and Information
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• v.10 no.3 s.35
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• pp.119-132
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• 2005

The health care system revolutionized by the use of information and communication technologies. Computer information processing and electronic communication technologies play an increasingly important role in the area of health care. We propose a new role based access control model for pervasive health care systems, which changed location, time, environment information. Also our model can be solved the occurrence of an reduction authority problem to pervasive health care system at emergency environment. We propose a new role based access control model for pervasive health care systems, which combines role-to-role delegations, negative permission, context concept and dynamic context aware access control. With out approach we aim to preserver the advantages of RBAC and offer groat flexibility and fine-grained access control in pervasive healthcare information systems.

• Journal of the Korea Society of Computer and Information
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• v.19 no.11
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• pp.97-103
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• 2014

The access control means the process to record and manage access restrictions and permits for protecting information in records. This paper emphasizes the control of access and authorization based on the roles and the data using activities of users as task performers. Also, it requires to gain the necessary approval in advance for important tasks such as mass inquiry and change on important information to influence the very existence of the whole organization. And then, it suggests that it is necessary to control some session of information with non-activity for certain time. Generally, this paper is to explain security elements of access control through various cases.

• International Journal of Computer Science & Network Security
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• v.21 no.7
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• pp.331-340
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• 2021

The Internet of Things (IoT) is a rapidly growing physical network that depends on objects, vehicles, sensors, and smart devices. IoT has recently become an important research topic as it autonomously acquires, integrates, communicates, and shares data directly across each other. The centralized architecture of IoT makes it complex to concurrently access control them and presents a new set of technological limitations when trying to manage them globally. This paper proposes a new decentralized access control architecture to manage IoT devices using blockchain, that proposes a solution to concurrency management problems and enhances resource locking to reduce the transaction conflict and avoids deadlock problems. In addition, the proposed algorithm improves performance using a fully distributed access control system for IoT based on blockchain technology. Finally, a performance comparison is provided between the proposed solution and the existing access management solutions in IoT. Deadlock detection is evaluated with the latency of requesting in order to examine various configurations of our solution for increasing scalability. The main goal of the proposed solution is concurrency problem avoidance in decentralized access control management for IoT devices.

• Journal of the Korea Society of Computer and Information
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• v.6 no.1
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• pp.60-66
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• 2001

We designed a role-based access control model that can resolve the complicated tasks of control requirements. The designed access control model can control permissions efficiently use of a role-based access control. It guarantees the confidentiality integrity and availa information making use of identity-based and rule-based access controls. It can also centre information flow. Our access control model protects resources from unauthorized accesses b multi-level security policies such as role, security level, integrity level and ownership.

• Journal of the Korea Society of Computer and Information
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• v.6 no.4
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• pp.119-124
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• 2001

In the paper, is proposed a secure role-based access control model that not only has s functions such as security, integrity and flow control, but also can easily meet access requirements of role-based social organizations. The proposed role-based access control mod designed based on proven existing rule-based access control mechanisms in order to be app real access control systems. The model proposed in the paper is simple and secure. It can be used for the web-based application systems working on the Internet.

• Proceedings of the Korea Database Society Conference
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• 1997.10a
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• pp.472-482
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• 1997

Multi-dimensional data play a crucial role in various fields, as like computer graphics, geographical information system, and multimedia applications. Indexing method fur multi-dimensional data Is a very Important factor in overall system performance. What is proposed in this paper is a new dynamic access method for spatial objects called HL-CIF(Hierarchically Layered Caltech Intermediate Form) tree which requires small amount of storage space and facilitates efficient query processing. HL-CIF tree is a combination of hierarchical management of spatial objects and CIF tree in which spatial objects and sub-regions are associated with representative points. HL-CIF tree adopts "centroid" of spatial objects as the representative point. By reflecting objects′sizes and positions in its structure, HL-CIF tree guarantees the high spatial locality of objects grouped in a sub-region rendering query processing more efficient.