• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.9A
• /
• pp.762-771
• /
• 2005

In this paper, an efficient Adaptive quality-of-service (QoS) traffic control scheme with priority scheduling is proposed for the multimedia traffic transmission over wireless access networks. The objective of the proposed adaptive QoS control (AQC) scheme is to realize end-to-end QoS, to be scalable without the excess signaling process, and to adapt dynamically to the network traffic state according to traffic flow characteristics. Here, the reservation scheme can be used over the wireless access network in order to get the per-flow guarantees necessary for implementation of some kinds of multimedia applications. The AQC model is based on both differentiated service model with different lier hop behaviors and priority scheduling one. It consists of several various routers, access points, and bandwidth broker and adopts the IEEE 802.1 le wireless radio technique for wireless access interface. The AQC scheme includes queue management and packet scheduler to transmit class-based packets with different per hop behaviors (PHBs). Simulation results demonstrate effectiveness of the proposed AQC scheme.

• Journal of information and communication convergence engineering
• /
• v.10 no.2
• /
• pp.156-161
• /
• 2012

An increasing number of people who use a smart phone or tablet PC are accessing wireless networks in public facilities including cafes and shopping centers. For example, iPhones and Android Phones have been available since 2010. However, security incidents may occur through all sorts of malicious code infection of users' personal information during the use of an insecure wireless network. In this paper, we will describe the Wi-Fi protected access (WPA) and WPA2 encryption systems used to access a wireless network from a smart phone and tablet PC, and demonstrate the access point (AP) hacking process in a wireless network to which a password is applied on the basis of the analyzed WPA and WPA2 passwords. We will analyze the method of successful AP hacking and propose an approach to enhancing wireless LAN security. This study will contribute to enhancing the security and stability of wireless networks.

• Journal of the Korean Society for Library and Information Science
• /
• v.29
• /
• pp.281-304
• /
• 1995

The purpose of this study is to identify the degree to which the card catalog in a university library serves its users and to provide useful information for the design of conversion from card catalog to online catalog. From August 19th to September 16th 1995, 278 users of Duksung Women's University Library were randomley selected and surveyed in terms of card catalog use, success rate of card searching, and catalog use training received. Major findings are as follows: 1. Taking into considerations the fact that Library users tended to use more heavily oriental card catalog$(61.8\%)$ than western card catalog$(8.3\%)$ or classification card catalog$(26.3\%)$, oriental card catalog should be designed to improve its search function of the catalog. 2. It was found that the university library card catalog was not easy to use by $49.3\%$ of the users of Duksung University Library. 3. One of main reasons why the card catalog is hard to use is that there is no subject card to which users can access for subject searching. Besides, users have difficulties in locating appropriate classification numbers for subjects which users are interested in. 4. When success rate is defined as finding appropriate cards in catalog boxes, the success rate was reported to be $87.0\%$. 5. The major access points of known items which library users utilized mostly were author$(18.3\%)$ and title$(74.5\%)$. 6. In case of translated versions of foreign materials, original author name cards instead of pronounced original name card written in Korean were given to them as access points. $79.9\%$ of library users of Duksung Women's University insisted that both original and pronounced author name writ':en in Korean should be given as access points to foreign authors for the sake of user's convenience. 7. Formal training programs for card catalog use were found not to be sufficient. Small group informal training courses should be offered to users who need to get information for catalog use by library staffs. 8. Considering the trend that orders of access points have been changed from title, author and subject in card catalog to title, keyword, and author in online catalog, the existing card catalog of Duksung Women's University is expected not to meet future users' needs for subject searching unless the funcions of subject searching of catalog is improved.

• 한국정보통신설비학회:학술대회논문집
• /
• 2009.08a
• /
• pp.208-210
• /
• 2009

Currently, Wireless LAN(WLAN) service is widely deployed to provide high speed wireless Internet access through the mobile stations such as notebook and PDA. To provide enhanced security and user access control in the public WLAN area, WLAN access points should have the capability of IEEE 802.1x-based user authentication and authorization functionality. In this paper, we provide a brief understanding of IEEE 802.1x standards and related protocols like EAPOL(Extended Authentication Protocol Over LAN), EAP, RADIUS and describe how the IEEE 802.1x is designed and implemented in our embedded linux-based WLAN AP which is named i-WiNG. (Intelligent Wireless Internet Gateway). For the network security and user authenti -cation purposes, a supplicant who wants to access Internet should be authorized to access the AP port using the EAPOL.

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

• Journal of Korea Society of Industrial Information Systems
• /
• v.25 no.4
• /
• pp.39-47
• /
• 2020

We propose a multi-access points transmit power control algorithm in consideration of the channel estimation error and the multi-rate service. In the real communication systems, the channel estimation at the receiver side is imperfect due to limited number of pilot symbol usage. Furthermore, the multi-rate service is supported. We theoretically prove the uniqueness and the convergence of the proposed algorithm in multi-rate service environment. The proposed algorithm composes of one inner loop part and one outer loop part. Simulation results show that 1) the inner loop algorithm guarantees convergence of the transmit power level and the multi-rate service, 2) the outer loop algorithm compensates for the channel estimation error.

• Journal of Korean Society of Archives and Records Management
• /
• v.18 no.4
• /
• pp.231-257
• /
• 2018

This paper aims to suggest a facet-based ontology model that can help sort and access records of dispersed families to address these problems. The facet systematically defines the categories of target concepts, which can create diverse and multiple access points. Using the top-down and bottom-up approaches, the facets, which consist of five upper classes and 18 lower classes, were derived for the records of dispersed families. The proposed ontology model was evaluated by real users. The results show that, overall, the ontology is complete and relevant in terms of access points, availability of context information of the records, and description elements for search and use of the records on dispersed families.

• Journal of electromagnetic engineering and science
• /
• v.19 no.1
• /
• pp.20-30
• /
• 2019

A wide-band multiple-input multiple-output (MIMO) antenna with dual-band (2.4 and 5 GHz) operation is proposed for premium indoor access points (IAPs). Typically, an omni-directional pattern is used for dipole antennas and a directional radiation pattern is used for patch antennas. In this paper, both antenna types were used to compare their performance with that of the proposed $2{\times}2$ MIMO antenna. We simulated and measured the performance of the MIMO antenna, including the isolation, envelope correlation coefficient (ECC), mean effective gain (MEG) for the IAPs, and the throughput, in order to determine its communication quality. The performance of the antennas was analyzed according to the ECC and MEG. The proposed antenna has sufficient performance and excellent characteristics, making it suitable for IAPs. We analyzed the communication performance of wireless networks using the throughput data of a typical office environment. The network throughput of an 802.11n device was used for the comparison and was conducted according to the antenna type. The results showed that the values of the ECC, MEG, and the throughput have unique characteristics in terms of their directivity, antenna gains, isolation, etc. This paper also discusses the communication performance of various aspects of MIMO in multipath situations.

• Journal of Korean Library and Information Science Society
• /
• v.39 no.4
• /
• pp.261-281
• /
• 2008

This study surveyed the retrieval systems for digital information resources of the university libraries in Busan, Ulsan, Gyeongnam districts and the vendors. Kinds of access points and retrieval conditions (Boolean logic, methods of index term identification, and particularities of the retrieval) of the libraries' systems are various and different to each other. Access points of the vendors' systems are unessentially various and different to each other, but the retrieval conditions are rather elaborated. Upon the result the suggestions for the standardization of digital information retrieval system are offered.

• International Journal of Contents
• /
• v.5 no.2
• /
• pp.59-63
• /
• 2009

Since it is hard to use GPS for tracking mobile user in indoor environments, much research has focused on techniques using existing wireless local area network infrastructure. Signal strength received at a fixed location is not constant, so fingerprinting approach which use pattern matching is popular. But this approach has to pay additional costs to determine user location. This paper proposes a new approach to find user's location efficiently using an index scheme. After analyzing characteristics of RF signals, the paper suggests the data processing method how the signal strength values for each of the access points are recorded in a radio map. To reduce computational cost during the location determination phase, multidimensional indexes for radio map with the important information which is the order of the strongest access points are used.