• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.12
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• pp.4269-4292
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• 2014

Currently, increasing numbers of access points (AP) are being deployed in enterprise offices, campuses and municipal downtowns for flexible Internet connectivity, but most of these access points are idle or redundant most of the time, which causes significant energy waste. Therefore, with respect to power conservation, applying energy efficient strategies in WIFI networks is strongly advocated. One feasible method is dynamically managing network resources, particularly APs, by powering devices on or off. However, when an AP is powered on, the device is initialized through a long boot time, during which period clients cannot be associated with it; therefore, the network performance would be greatly impacted. In this paper, based on a global view of an entire WLAN, we propose an AP selection technology, known as Temporary Access Selection (TAS). The criterion of TAS is a fusion metric consisting of two evaluation indexes which are based on throughput and battery life, respectively. TAS is both service and clients' preference specific through balancing the data rate, battery life and packet size. TAS also works well independently in traditional WLANs in which no energy efficient strategy is deployed. Moreover, this paper demonstrates the feasibility and performance of TAS through experiments and simulations with Network Simulator version 3 (NS3).

• Journal of Korean Library and Information Science Society
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• v.55 no.2
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• pp.109-132
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• 2024

As the bibliographic environment has been evolved towards linked data and semantic web, revision of KCR5 based on RDA is also in progress in Korea. Even authorized access points play an important role in identification and linkage between resources in the evolving bibliographic environment. However, the original RDA applied by KCR5 does not provide authorized access points for all entities. Based on the analysis of the authorized access point of manifestation in RDA 2020, this research identified properties and proposed a linking structure of the authorized access point that can be applied to the revision of KCR5. An authorized access point for manifestation is an access point that considers both intellectual and physical aspects, and can be the foundation for linking and identifying actual resources. The proposed structure is expected to be a linking structure for authority record optimized to the current bibliographic environment, which can be helpful in the practical application of the authorized access point for manifestation.

• Journal of Korean Library and Information Science Society
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• v.52 no.4
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• pp.153-177
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• 2021

The revision of the Korean Cataloging Rules (KCR) is in progress in order to conform IFLA LRM conceptual model and to strengthen its internal stability. Religious works, along with musical works and legal works, have been treated as special and important in cataloging rules. This trend continues in the new cataloging rules that seek a bibliographic model that interconnects related materials. However since KCR2(1966), there are no rules for access points or specific rules on religious works. Under the circumstances, this study analyzed (1) the contents of religious works in the recently revised cataloging rules, (2) the access points and their functions for religious works implemented in online catalogs and authority system, and finally (3) the direction and scope of KCR revision. As a result of the study, this study suggested that it is necessary to prepare detailed rules for preferred title and authorized access points for various religious works in KCR. In conclusion, some issues for further discussion were summarized.

• Journal of Korean Library and Information Science Society
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• v.46 no.4
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• pp.207-226
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• 2015

FRBR and FRAD model, ICP, RDA, NCR Revision are analyzed for the composition of KCR4 Revision. Based on the results, follows are suggested. 1) Entities are divided into work, expression, manifestation, item, person, family, corporate body, concept, object, event, place. 2) Entire cataloging rules are grouped into 'attributes' and 'relationships', and then 'attributes' is divided into attributes describing and access points constructing. 3) Attributes describing is divided into attributes describing of works, expressions, manifestations, items, persons, families, corporate bodies, and arranged as the sequence. 4) Access points constructing is divided into access points constructing of works, expressions, persons, families, corporate bodies, and arranged as the sequence. 5) 'Relationships' is divided into other relationships between group 1 entities, and relationships between persons, families and corporate bodies.

• Journal of Electrical Engineering and Technology
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• v.8 no.1
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• pp.183-189
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• 2013

In this paper, we propose a capacity modeling method for Bluetooth based LBSs (Location Based Services) between Bluetooth APs(Access Points) and mobile phones. In order to do this, we consider the entrance and exit of the users to and from the AP. Using parameters such as the connection time, data transmission time and number of users in the AP zone, we analyze the capacity of a Bluetooth AP using an appropriate queuing model. The required number of APs in a certain zone is estimated from the number of users in the zone using the proposed queuing model. By performing simulations and experiments, the validity and applicability of the proposed method are verified.

• Journal of Information Technology Services
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• v.9 no.3
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• pp.145-161
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• 2010

Recently, identifying user locations is becoming important as the society evolves into an ubiquitous society with the innovation of information technology. Particularly, many researches on identifying user locations are headed in direction to identify locations of users in the indoors, because a GPS that is widely used to identify the locations of users in the outdoors is inapplicable in the indoors. However, those researches are mostly not useful to general indoor environment because they are performed in a specific environment with specialized or customized devices such as UWB, RFID. Therefore, in this paper we propose a effective method to identify user locations in general indoor environments with wireless local network access points. Our approach enables to identify user location efficiently by measuring signal power of access points around the user and using the FRIIS formula which is used to calculate the distance among the things.

• Journal of IKEEE
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• v.26 no.2
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• pp.186-195
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• 2022

In this paper, we propose a new algorithm to improve the accuracy of indoor positioning techniques using Wi-Fi access points as beacon nodes. The proposed algorithm is based on the Weighted Centroid algorithm, a popular method widely used for indoor positioning, however, it improves some disadvantages of the Weighted Centroid method and also for other kinds of indoor positioning methods, by using the received signal strength correction method and genetic algorithm to prevent the signal strength fluctuation phenomenon, which is caused by the complex propagation environment. To validate the performance of the proposed algorithm, we conducted experiments in a complex indoor environment, and collect a list of Wi-Fi signal strength data from several access points around the standing user location. By utilizing this kind of algorithm, we can obtain a high accuracy positioning system, which can be used in any building environment with an available Wi-Fi access point setup as a beacon node.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.8
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• pp.1022-1029
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• 2020

We investigate the joint selection problem of the transmit power level and the best access point for multi-access points. We further reduce the transmit power by jointly optimizing the transmit power and the access point selection. Our aim is to minimize the total transmit power, while each terminal maintains minimum signal to interference ratio requirement. We observe that the optimum solution can be achieved through proposed iterative algorithm for both TA link and AT link. Simulation results show that proposed algorithm (joint optimization of transmit power level and access point) outperforms the algorithm which optimizes the transmit power only. We also observe that the duality between the TA link and AT link does not hold in multi-access points environment. Accordingly, the resulting power vectors and the access point vectors for TA link and AT link are different in general.

• Journal of Communications and Networks
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• v.18 no.2
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• pp.135-149
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• 2016

Cloud radio access network (C-RAN) refers to the virtualization of base station functionalities by means of cloud computing. This results in a novel cellular architecture in which low-cost wireless access points, known as radio units or remote radio heads, are centrally managed by a reconfigurable centralized "cloud", or central, unit. C-RAN allows operators to reduce the capital and operating expenses needed to deploy and maintain dense heterogeneous networks. This critical advantage, along with spectral efficiency, statistical multiplexing and load balancing gains, make C-RAN well positioned to be one of the key technologies in the development of 5G systems. In this paper, a succinct overview is presented regarding the state of the art on the research on C-RAN with emphasis on fronthaul compression, baseband processing, medium access control, resource allocation, system-level considerations and standardization efforts.

• Journal of the Korean Society for Library and Information Science
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• v.46 no.2
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• pp.261-280
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• 2012

This study seeks to replace PaRIS Principles and find directions of revising KCR4 by analyzing the international Cataloging Principles 2009(ICP 2009) established in the environment of Machine Readable Cataloging. ICP 2009 was reflected in cataloging rules such as RDA and ISBD 2010 as the minimal principles for uniformity in establishing each nation's cataloging rules. In contrary, KCR4 needs to be revised because it has never been changed after 2003, and has only description rules without any rules for the choice and forms of access points. Therefore, this study aims to grasp requirements that should be reflected in KCR4 through analyzing ICP 2009. In first step, it is to grasp the features of ICP 2009 by comparing PaRIS Principle and ICP 2009 and to compare KCR4 in aspects of ICP 2009. The detailed elements for comparison between ICP 2009 and KCR4 are scope, general principles, entitles, attributes, and relationships, objectives and functions of the catalogue, bibliographic description, access points, foundations for search capabilities as the contents of ICP 2009. As a result, this study could give some directions of KCR4 in the future. First, ISBD 2010 and conceptual models should be reflected in KCR4 in description. Second, it should regulate the authority access points in KCR4 based on ICP 2009. Third, it will describe essential access points of work and expression attributes in bibliographic records and authority records to find works and expression. This study will contribute to guide the national cataloging rules.