• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3623-3627
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• 2012

The modern society has become full-fledged entry into the information age since spread of Internet. In the information age, internet was developed from the wired access to the wireless Internet access. When a surge in demand for wireless Internet access, efficiency and performance of 2.4GHz band which leads to saturation of the communication was significantly fall. Accordingly, the communication of the 5GHz band came to be interested. In this paper, we studied the design and fabrication of u-slot microstrip patch antenna to be used in wireless communication systems operating at around 5GHz band. To obtain antenna parameters such as patch size, inter patch space, antenna was simulated by HFSS(High Frequency Structure Simulator). From these parameters, u-slot microstrip patch antenna is fabricated using FR-4 substrate of dielectric constant 4.4. The characteristics of fabricated antenna were analyzed by network analyzer.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.7
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• pp.3339-3352
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• 2016

In ciphertext-policy attribute-based encryption (CP-ABE) scheme, a user's secret key is associated with a set of attributes, and the ciphertext is associated with an access policy. The user can decrypt the ciphertext if and only if the attribute set of his secret key satisfies the access policy specified in the ciphertext. In the present schemes, access policy is sent to the decryptor along with the ciphertext, which means that the privacy of the encryptor is revealed. In order to solve such problem, we propose a CP-ABE scheme with hidden access policy, which is able to preserve the privacy of the encryptor and decryptor. And what's more in the present schemes, the users need to do excessive calculation for decryption to check whether their attributes match the access policy specified in the ciphertext or not, which makes the users do useless computation if the attributes don't match the hidden access policy. In order to solve efficiency issue, our scheme adds a testing phase to avoid the unnecessary operation above before decryption. The computation cost for the testing phase is much less than the decryption computation so that the efficiency in our scheme is improved. Meanwhile, our new scheme is proved to be selectively secure against chosen-plaintext attack under DDH assumption.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.12
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• pp.4545-4566
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• 2021

The evolution of IoT technology is having a significant impact on people's lives. Almost all areas of people's lives are benefiting from increased productivity and simplification made possible by this trending technology. On the downside, however, the application of IoT technology is posing some security challenges, among them, unauthorized access to IoT devices. This paper presents an Attribute-based Access Control Fog architecture that aims to achieve effective distribution, increase availability and decrease latency. In the proposed architecture, the main functional points of the Attribute-based Access Control are distributed to provide policy decision and policy information mechanisms in fog nodes, locating these functions near end nodes. To evaluate the proposed architecture, an access control engine based on the Attribute-based Access Control was built using the Balana library and simulated using EdgeCloudSim to compare it to the traditional cloud-based architecture. The experiments show that the fog-based architecture provides robust results in terms of reducing latency in making access decisions.

• The KIPS Transactions:PartD
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• v.19D no.1
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• pp.113-120
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• 2012

Today, Internet users can easily create and share the digital contents with others through various online content sharing services such as YouTube. So, many portal sites are flooded with lots of user created contents (UCC) in various media such as texts and videos. Estimating popularity of UCC is a crucial concern to both users and the site administrators. This paper proposes a method to predict the popularity of Internet articles, a kind of UCC, using the dynamics of the online contents themselves. To analyze the dynamics, we regarded the access counts of Internet posts as the popularity of them and analyzed the variation of the access counts. We derived a model to predict the popularity of a post represented by the time series of access counts, which is based on an exponential function. According to the experimental results, the difference between the actual access counts and the predicted ones is not more than 10 for 20,532 posts, which cover about 90.7% of the test set.

• The Transactions of the Korea Information Processing Society
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• v.6 no.11S
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• pp.3190-3198
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• 1999

Because of the rapid growth of the mobile communication, the need for the mobile internet access has grown up as well. since the current mobile communication network, however, is optimized for a voice communication system, which exclusively occupies a channel for a given time, it is not suitable for variable rate packet data. In order to support the mobile internet access, it is essential do design a reasonable packet switching network which supports the mobility. Since mobile packet network has longer latency, high speed switching and QoS are required to meet the user's requirements. In this paper, we suggest an resonable way to construct a network and its operation procedures utilizing GPRS(General Packet Radio Service) network and MPLS(Multi Protocol Label Switching) to provide a high speed switching and QoS mobile internet access. GPRS is used as a network which supports the mobility and MPLS guarantees the QoS and high speed IP protocol transmission based on the ATM switching technology.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.1
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• pp.34-39
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• 2007

According to the active use of internet the need for security in various environment is being emphasized. Moreover with the broad use of Messenger on PC and P2P applications. the security and management of individual hosts on internet became very important issues. Therefore in this paper we propose the design and implementation of a host based access control system for the hosts on internet including window based PC which provides access control, information on packets, and record and monitoring of log files.

• Journal of Korean Public Health Nursing
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• v.26 no.2
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• pp.328-340
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• 2012

Purpose: This study explored the degree of internet addiction and its influencing factors in lower grade elementary school children in rural areas. Methods: Subjects included 1,137 elementary school children. A structured questionnaire consisting of questions internet addiction, family function and school life satisfaction was used for data collection. Descriptive statistics, ${\chi}^2$-test, ANOVA and Correlation and Regression were performed using a SPSS program. Results: Among the subjects, 85.8% were regular users, 8.1% were potential risk users, and 6.1% were high-risk users. Career of internet use, daily internet access time, the number of conversations per week, the number of times spent eating out and traveling with parents within the last month and activities with friends, and satisfaction on school life differed significantly according to the degree of internet addiction. Finally, among the factors studied, daily internet access time, conversations within family, activities with friends and school life satisfaction in children in early elementary school was 20.7% of the explanatory power of the subjects' degree of internet addiction, collectively. Conclusion: Use of the internet by early elementary school children should be monitored and strategies to promote familial conversations, activities with peers and school life satisfaction should be developed.

• Journal of Internet Computing and Services
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• v.18 no.2
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• pp.1-11
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• 2017

There are two kinds of wireless network access to a certain place by using smart devices - 1) open (anonymous) - access and 2) user-authorized access. The open-access is a non-authorization connection method which does not need to require Smart device's user authorized information. It means open-access use only user's SSID (Service Set Identifier) information to access the wireless AP devices following public wireless network standard. This access mechanism is not suitable to use all of public wireless networks because users have to get all wireless network information around them. As a result, huge data for smart devices should be one of the most critical overload problems for them. Secondly, the user-authorized access method uses wireless network information (SSID and password) chosen by the users. So, the users have to remember and use the network access information data manually whenever accessing the network. Like open-access, this access method also has the operational and inconvenient problem for the users - manually inputting access information whenever connecting to the network. To overcome this problem in both schemes, we propose two improved wireless network access methods: 1) the implementation of automatic AP connection mechanism using user-authorization and iBeacon messages, and 2) SSID registration form for public wireless networks.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.215-223
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• 2010

New information technologies make it easy to access and acquire information in various ways. However, It also enable powerful and various threat to system security. The prominent database technology challenging these threats is access control. Currently, to keep pace with the new paradigms, new extended access control methods are challenged. We study access control with uncertain context. With respect to access control, it is possible that there is a discrepancy between the syntactic phrase in security policies and that in queries, called semantic gap problem. In our semantic access control, we extract semantic implications from context tree and introduce the measure factor to calculate the degree of the discrepancy, which is used to control the exceed privileges.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.8
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• pp.2590-2606
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• 2014

A problem related to deployment of femtocells is how to manage access of users to radio resources. On one hand, all resources of the femtocell can be reserved for users belonging to a closed subscriber group (CSG), which is a set of users defined by a femtocell subscriber. This approach, known as closed access, however, increases interference to users not included in the CSG as those users do not have a permission to access this femtocell. Contrary, resources can be shared by all users with no priority in an open access mode. In this case, the femtocell subscriber shares radio as well as backhaul resources with all other users. Thus, throughput and quality of service of the subscriber and the CSG users can be deteriorated. To satisfy both the CSG as well as non-CSG users, a hybrid access is seen as a compromise. In this paper, we propose a new approach for sharing radio resources among all users. As in common cases, the CSG users have a priority for usage of a part of resources while rest of the resources is shared by all users proportionally to their requirements. As the simulation results show, the proposed resource sharing scheme significantly improves throughput of the CSG users and their satisfaction with granted bitrates. At the same time, throughput and satisfaction of the non-CSG users is still guaranteed roughly at the same level as if conventional sharing schemes are applied.