• Journal of the Korea Society of Computer and Information
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• v.15 no.11
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• pp.125-133
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• 2010

A policy based resource management framework is proposed, that supports the optimal QoS by applying resources management function which is changed according to the status of mobile terminal and heterogeneous connections to hand-over process of mobile terminals based on heterogeneous network. To assess the performance of policy based resource management framework proposed in this thesis, in case of applying weighted policy for selecting optimal cell in hand-over occurring among duplicated heterogeneous connections, the transmission delay was remarkably enhanced as the number of multimedia sessions increased. This means, in case of QoS deterioration of multimedia session occurring in service connection, hand-over was executed with the optimal connection.

• The KIPS Transactions:PartC
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• v.11C no.3
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• pp.387-394
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• 2004

One of the main challenges in personal communication services(PCS ) Is to locate many mobile terminals that nay move from place to place frequently. This kind of system operation is called location management. This task entails sophisticated signaling traffic and database queries. Several strategies have been proposed to improve the efficiency of location management. These strategies use location register databases to store the current locations of mobile terminals, and are vulnerable to failure of the location register databases. In this paper, we propose a fault-tolerant pointer forwarding scheme with distributed home location register in order to tolerate the failure of location registers. The performance of the proposed scheme is evaluated analytically by simulation, and Is compared with Biaz's bypass forwarding strategy and two-path forwarding strategy.

• Journal of Internet Computing and Services
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• v.1 no.1
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• pp.35-46
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• 2000

One of the main chalenges in personal communication services (PCS) is to locate many mobile terminals that may move frequently from place to place. Such a system operation is called location management. Many network signaling traffic, and database queries are required to achieve such a task. Several strategies have been proposed to improve the efficiency of location management. These strategies use location register databases to store the current location on mobile terminals, and are vulnerable to failure of the location registers. In this paper, we propose a fault-tolerant pointer forwarding with distributed home location register (FT-RFDHLR) to tolerate the failure of location registers. The performance of the proposed method is evaluated by an analytical model, and is compared with thew pointer forwarding with the single home location register (PFSHLR), the pointer forwarding with distributed home location register (PFDHLR), Biaz's bypass forwarding strategy (BFS) and two-path forwarding strategy (TPFS).

• Journal of the Korea Computer Industry Society
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• v.2 no.9
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• pp.1219-1224
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• 2001

There can exist unidirectional links due to asymmetric property of mobile terminals or current wireless environments on practical mobile ad hoc networks. However, at present, the existing mobile ad hoc routing protocols are implemented to support only bidirectional links. Thus, in this paper, we extend the existing dynamic source routing protocol in order to implement a new routing protocol, which is fit to mobile ad hoc networks containing unidirectional links. For performance evaluation, we use combinations of mobility scenario files and connection pattern files from Carnegimelon Univ. We consider received data rate and average route discovery time as evaluation items, which are compared and evaluated for three suggested route discovery methods.

• The KIPS Transactions:PartC
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• v.9C no.6
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• pp.911-918
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• 2002

An important issue in the design of future Personal Communication Service (PCS) networks is the efficient management of location information. In this paper, we propose an adaptive distributed dynamic location management algorithm that stores the position of the mobile terminal in k of the n location information databases (LIDs). The proposed algorithm chooses adaptively k. replication factor according to both the space locality of LIDs in wireless mobile networks and the location query popularity to local mobile terminal from remote mobile terminals. The performance of proposed algorithm is evaluated by both an analytical model and a simulation. Based on the results of performance evaluation, we know that the performance of the proposed algorithm is better than that of Krishnamurthi's algorithm regardless of call-mobility ratio.

• The Journal of the Convergence on Culture Technology
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• v.6 no.4
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• pp.797-802
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• 2020

Over the past few years, smart devices, including smartphones, have been continuously required by users based on portability. The performance is improving. Ubiquitous computing environment and sensor network are also improved. Due to various network connection technologies, mobile terminals are widely used. Smart terminals need technology to make energy monitoring more detailed for more stable operation during use. The smart terminal which is light in small size generates the power shortage problem due to the various multimedia task among the terminal operation. Various estimation hardwares have been developed to prevent such situation in advance and to operate stable terminals. However, the method and performance of estimating the remaining amount are not relatively good. In this paper, we propose a method for estimating the remaining amount of smart terminals. The Capacity Estimation of lithium ion cells for stable operation was estimated based on machine learning. Learning the characteristics of lithium ion cells in use, not the existing hardware estimation method, through a map learning algorithm using machine learning technique The optimized results are estimated and applied.

• Electronics and Telecommunications Trends
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• v.35 no.5
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• pp.14-29
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• 2020

The 6G mobile communication system will become a backbone infrastructure around 2030 for the future digital world by providing distinctive services such as five-sense holograms, ultra-high reliability/low-latency, ultra-high-precision positioning, ultra-massive connectivity, and gigabit-per-second data rate for aerial and maritime terminals. The recent remarkable advances in machine learning (ML) technology have recognized its efficiency in wireless networking fields such as resource management and cell-configuration optimization. Further innovation in ML is expected to play an important role in solving new problems arising from 6G network management and service delivery. In contrast, an approach to apply ML to a physical-layer (PHY) target tackles the basic problems in radio links, such as overcoming signal distortion and interference. This paper reviews the methodologies of ML-based PHY, relevant industrial trends, and candiate technologies, including future research directions and standardization impacts.

• Speech Sciences
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• v.15 no.2
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• pp.79-88
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• 2008

Recently demands for the speech technology-based products targeted for the mobile terminals such as cellular phones and PDA are rapidly increasing. And voting-based speaker identification algorithm is known to have a good performance in the mobile environment, since it works well with small amount of speaker training data. In this paper, we proposed a method to improve the performance of this voting based speaker identification system by using the observation confidence value which is derived from the function of SNR each frame. The proposed method is evaluated with ETRI cellular phone DB which is made for the speaker recognition task. The experimental results show that the proposed method has better performance of 2-3% identification rate than the conventional GMM method.

• Journal of the Korea Society for Simulation
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• v.10 no.2
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• pp.47-60
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• 2001

In mobile wireless network efficient location management for tracking and finding mobile users is a critical issue. The traffic for location update can be excessive, especially at the base stations that are near to the location area (LA) boundaries. In this paper we propose a new location update scheme which can significantly reduce the signaling traffic for location update. It is based on the virtual layer approach employing SubMSCs. The virtual layer is laid upon the original layer of LAs such that the mobile terminals moving around the boundary cells of adjacent LAs become to move within a virtual LA. As a result, the location update traffic is substantially reduced compared to overlapping scheme which is the most recent and efficient location update scheme.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1447-1450
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• 2002

In this paper, we propose a new access method named UR (Use. Relay) scheme to improve the channel efficiency in mobile communications. In UR scheme, packets of a data terminal that do not demand real time communications are relayed by other terminals during their inactive periods, which ue communicating with the base station through a fixed channel at that time. Simulation results show that with UR scheme, the blocking probability md the throughput are improved considerably with an allowable increase in the average delay.