• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.9B
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• pp.771-777
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• 2004

In a COMA system, the capacity is variable and mainly depends on multiple access interference. The multiple access interference has a deep relationship with transmitted or received power. The capacity of COMA2000 system is considered to be limited by the forward link capacity. In this paper, we show that the forward link cell load can be represented by the total transmitted power of base station and we propose a forward link call admission control (CAC) strategy for COMA2000 system. The proposed call admission scheme adopts the rate control algorithm for data call. This call admission scheme enables the system to utilize radio resource dynamically by controlling data rate according to the cell load status, and enhance the system throughput and grade of service (GoS). quality of service(QoS) such as blocking and outage probability.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.2
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• pp.181-192
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• 2017

Internet of Things includes the whole process of collected information generated from a variety of objects, as well as analyzing and sharing it, and providing useful information services to people. This study seeks ways to improve security and safety in the areas of service security technology, ID management technology and service access control, all of which take place in the IoT environment. We have implemented the services that can design and issue C&C (Certificate and Capability) service token authentication, which is based on a public key, to improve the service security. In addition, we suggest LCRS (Left Child-Right Sibling) resource model management for the efficient control of resources when generating the resource services from the data collected from node devices. We also implemented an IoT services platform to manage URL security of the resource services and perform access control for services.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1855-1858
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• 2002

A number of MPLS ATM systems have been proposed to increase the access speed of current routers, which only support the best-effort service. However, the MPLS ATM systems have to support the so-called differential service, which discriminates the applications according to the service class because they do not be satisfied the Internet users who use diverse applications. In this paper, to support this differential service a detailed forwarding procedure based on a LSP control method and an application-based marking algorithm is suggested. The LSP control method establishes several different LSPs for each FEC according to the service class and the application-based marking algorithm chooses a proper differential service depending on the application category. Also, a design scheme of forwarding engine, which can be easily implemented with a minimum modification of existing MPLS ATM systems is proposed. And, the best simulation result of high priority application category is gained when the proposed forwarding algorithm is comparedwithexistingalgorithms.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.11
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• pp.4331-4346
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• 2015

The femtocell network, which is designed for low power transmission and consists of consumer installed small base stations, coexists with macrocells to exploit spatial reuse gain. For its realization, cross-tier interference mitigation is an important issue. To solve this problem, we propose a joint access and power control scheme that requires limited information exchange between the femto and macro networks. Our objective is to maximize the network throughput while satisfying each user's quality of service (QoS) requirement. To accomplish this, we first introduce two distributed interference detection schemes, i.e., the femto base station and macro user equipment based schemes. Then, the proposed scheme dynamically adjusts the transmission power and makes a decision on the access mode of each femto base station. Through extensive simulations, we show that the proposed scheme outperforms earlier works in terms of the throughput and outage probability.

• Journal of the Korea Society of Computer and Information
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• v.13 no.5
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• pp.103-110
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• 2008

Due to the development of the e-commerce, the shopping mall such as auction collects and manages the personal information of the customers for efficient service. However, because of the leakage of the Personal information in auction, the image of the companies as well as the information subjects is damaged. Even though the organizations and the companies store the personal information as common sentences and protect using role based access control technique, the personal information can be leaked easily in case of getting the authority of the database administrator. And also the role based access control technique is not appropriate for protecting the sensitive information of the information subject. In this paper, we encrypted the sensitive information assigned by the information subject and then stored them into the database. We propose the personal policy based access control technique which controls the access to the information strictly according to the personal policy of the information subject. Through the proposed method we complemented the problems that the role based access control has and also we constructed the database safe from the database administrator. Finally, we get the control authority about the information of the information subject.

• The Journal of the Korea Contents Association
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• v.10 no.9
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• pp.79-87
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• 2010

This paper proposes a L3 handover method to minimize packet loss for supporting service continuity to IMS Terminal which has a single WLAN interface. The existing IMS based handover solution is able to support handover between different access networks in case that a terminal has multiple interfaces. That is, WLAN terminals need multiple interfaces to connect with one or more access networks. This proposed method configures IP address for the terminal in target WLAN previously by using Candidate Access Router Discovery(CARD) mechanism. Also, in the proposed method, service continuity server performs L3 connection establishment in target WLAN and registration to IMS server instead of the terminal. And then session control mechanism based on SIP is performed to support service continuity. We analyzed handover latency and signaling cost in the proposed method and existing method to show the improved performance by the proposed method.

• 한국정보통신설비학회:학술대회논문집
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• 2005.08a
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• pp.290-296
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• 2005

In this paper, we describe ubiquitous environments and the trend of convergence that is an evolution path of current telecommunication, and show the concept of broadband convergence network, service feature and evolution path. In order to converge wire and wireless communication, telecommunication and broadcasting, voice and data efficiently, broadband convergence network divides a network into service layer, control layer, transport layer, ubiquitous access and terminal layer. Broadband convergence network will be a network that can provide and control broadband multimedia services with QoS and securityof different and customized level. Then we depict characteristics and types of broadband multimedia service, and describe the characteristic of broadband convergence network. Finally, we show ubiquitous network based on the broadband convergence network to provide ubiquitous service which is a future telecommunication service. We also describe requirements of ubiquitous network such as an intelligent and context based platform, convergence terminals, ubiquitous computing devices, etc., and give various emerging technologies and those applications.

• Journal of Internet Computing and Services
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• v.16 no.1
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• pp.47-55
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• 2015

Recently, the environment of a hospital information system is a trend to combine various SMART technologies. Accordingly, various smart devices, such as a smart phone, Tablet PC is utilized in the medical information system. Also, these environments consist of various applications executing on heterogeneous sensors, devices, systems and networks. In these hospital information system environment, applying a security service by traditional access control method cause a problems. Most of the existing security system uses the access control list structure. It is only permitted access defined by an access control matrix such as client name, service object method name. The major problem with the static approach cannot quickly adapt to changed situations. Hence, we needs to new security mechanisms which provides more flexible and can be easily adapted to various environments with very different security requirements. In addition, for addressing the changing of service medical treatment of the patient, the researching is needed. In this paper, we suggest a dynamic approach to medical information systems in smart mobile environments. We focus on how to access medical information systems according to dynamic access control methods based on the existence of the hospital's information system environments. The physical environments consist of a mobile x-ray imaging devices, dedicated mobile/general smart devices, PACS, EMR server and authorization server. The software environment was developed based on the .Net Framework for synchronization and monitoring services based on mobile X-ray imaging equipment Windows7 OS. And dedicated a smart device application, we implemented a dynamic access services through JSP and Java SDK is based on the Android OS. PACS and mobile X-ray image devices in hospital, medical information between the dedicated smart devices are based on the DICOM medical image standard information. In addition, EMR information is based on H7. In order to providing dynamic access control service, we classify the context of the patients according to conditions of bio-information such as oxygen saturation, heart rate, BP and body temperature etc. It shows event trace diagrams which divided into two parts like general situation, emergency situation. And, we designed the dynamic approach of the medical care information by authentication method. The authentication Information are contained ID/PWD, the roles, position and working hours, emergency certification codes for emergency patients. General situations of dynamic access control method may have access to medical information by the value of the authentication information. In the case of an emergency, was to have access to medical information by an emergency code, without the authentication information. And, we constructed the medical information integration database scheme that is consist medical information, patient, medical staff and medical image information according to medical information standards.y Finally, we show the usefulness of the dynamic access application service based on the smart devices for execution results of the proposed system according to patient contexts such as general and emergency situation. Especially, the proposed systems are providing effective medical information services with smart devices in emergency situation by dynamic access control methods. As results, we expect the proposed systems to be useful for u-hospital information systems and services.

• Journal of Digital Convergence
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• v.14 no.2
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• pp.191-196
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• 2016

The organizations and companies establish personal information protection policy under the law and guidelines. They carry out access control without consideration for distinctiveness of the information although the damage degree varies when the information is leaked. Considering the distinctiveness, a policy needs to be made for individuals to protect his personal information. However, he is not able to write the policy because of lack of understanding the system. To write his own policy efficiently, the system that authorizes ones according to service list provided by organizations is necessary. This paper suggests the model and method that write personal policy for his information protection based on the service list provided by organizations. Through this model, fine-grained authorization and policy change are easily made and ultimately the access control customized according to one's own information is possible.

• The KIPS Transactions:PartA
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• v.13A no.4 s.101
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• pp.363-370
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• 2006

Currently, many people have been researching diverse mechansmims related to a resource access control in Grid environment. Mostly Grid user's resource access control was designed to authorize according to their attributes and roles. But, to provide Grid with resources continuously, a resource access based on utility computing must be controlled. So, in this paper we propose and implement mechanism that intergrates Grid accounting concept with resource access control. This mechanism calcuates costs of Grid service on the basis of accounting, and determines based on user's fund availibility whether they continue to make use of site resources or not. Grid jobs will be controlled according to a site resource access control policy only if the amount of available fund is less than its costs. If Grid job completed, resource consumer pays for the costs generated by using provider's idle resources. Therefore, this paper provides mechansim to be able to control user's resource access by Grid accounting, so that it is evaluated as the research to realize utility computing environment corresponding to economic principle.