• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.3B
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• pp.232-238
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• 2006

We propose a novel call admission control scheme which improves the handoff drop and the new call block probabilities of high priority services, minimizing the negative impact on low priority services, in multimedia service cellular networks. This paper proposes three schemes to solve this problem; the packing scheme in which available channels of a cell distributed to each frequency channel are concentrated on one frequency channel and a high transmission rate service is assigned to the frequency channel; the queuing scheme in which the queue is used for high transmission rate calls; and the power reallocation scheme in which the power assigned to calls under service is temporarily reduced and a high transmission rate service is allowed. The simulation results revealed that our scheme improved the drop and the block probabilities of the high priority services compared with the conventional scheme.

• KIISE Transactions on Computing Practices
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• v.21 no.5
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• pp.359-364
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• 2015

As Internet of Things(IoT) has become one of the most rapidly growing market in the world, the number of embedded Android devices has increased. Therefore, it is necessary to set up an environment that connects and cooperates between the devices via network. The environment requires an ability not only to obtain information about other devices through a network but to control remote devices by invoking remote procedures. This paper suggests the Remote Binder, which is a method for remote procedure call between devices operating on Android platform. It invokes procedures of other Android devices without any revisions via network by extending the binder structure which is used for inter-process communication in Android.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.11
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• pp.2399-2404
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• 2009

In cellular network systems one of the most significant quality metrics to measure quality of performance is the average number of call drops in a system. It ensures that the active calls in the system are successfully completed without being dropped in the mid communication for ultimate customer satisfaction. Hand-off mechanism increases cellular system reliability by seamless continuation of active calls by transferring active calls from one base station to another. In this paper, we study and propose a simple hand-off mechanism using game theory. We conclude that using the simple QoS utility function proposed in this paper, our optimal deterministic hand-off strategy is to transfer the active calls to the base station with greater signal-to-interference ratio (SIR) and greater number of available channels.

• Journal of Communications and Networks
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• v.12 no.6
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• pp.568-576
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• 2010

The paper presents a control architecture aimed at implementing bandwidth optimization combined with call admission control (CAC) over a digital video broadcasting (DVB) return channel satellite terminal (RCST) under quality of service (QoS) constraints. The approach can be applied in all cases where traffic flows, coming from a terrestrial portion of the network, are merged together within a single DVB flow, which is then forwarded over the satellite channel. The paper introduces the architecture of data and control plane of the RCST at layer 2. The data plane is composed of a set of traffic buffers served with a given bandwidth. The control plane proposed in this paper includes a layer 2 resource manager (L2RM), which is structured into decision makers (DM), one for each traffic buffer of the data plane. Each DM contains a virtual queue, which exactly duplicates the corresponding traffic buffer and performs the actions to compute the minimum bandwidth need to assure the QoS constraints. After computing the minimum bandwidth through a given algorithm (in this view the paper reports some schemes taken in the literature which may be applied), each DM communicates this bandwidth value to the L2RM, which allocates bandwidth to traffic buffers at the data plane. Real bandwidth allocations are driven by the information provided by the DMs. Bandwidth control is linked to a CAC scheme, which uses current bandwidth allocations and peak bandwidth of the call entering the network to decide admission. The performance evaluation is dedicated to show the efficiency of the proposed combined bandwidth allocation and CAC.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.12
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• pp.1113-1118
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• 2012

Smart grid and intelligent transportation system draw significant interest since they are considered as one of the green technologies. These systems require a large number of sensors, actuators, and controllers. Also, machine-to-machine (M2M) communications is important because of the automatic control. The LTE-Advanced networks is preparing a set of functions that facilitate the M2M communications, and particularly the development of an efficient call admission control mechanism is critical. A method that groups MTC devices according to QoS constraints and determines the admission depending on the QoS satisfaction is limitedly applied only if the data transmission period and the maximum delay are identical. This paper proposed a call admission control that is free from such limitation and also optimizes the admission process under the certain condition of the transmission period and maximum delay. The theorems regarding the proposed method are presented with the proofs. The simulations confirms its validity and shows it is better in call admission probability than existing works.

• Journal of KIISE:Computing Practices and Letters
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• v.7 no.5
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• pp.522-538
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• 2001

This paper presents a cal center which is a subsystem of a web-based real time monitoring system of intensive care units. Based on Computer-Telephony Integration (CTI) technology, the call center attempts to efficiently and automatically send messages to patients\` families, doctors, and other staffs in hospital via communication media suitable to the occasion. The problem of determining appropriate media can be very complicated by the urgency of a message, calling time, and communication media available to the target person. We use the Dempster-Shafer theory, one of the uncertainty handling methods, to determine the most suitable communication media that will transmit a message rapidly and safely. In addition, we use agent technology to perform the calling process without requiring the intervention of the user of the call center. this call center enables message transfer through various communication media in an integrated environment, and relieves medical staff from the calling process, which in turn will make a contribution toward enhancing medical service.

• The Transactions of the Korea Information Processing Society
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• v.4 no.10
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• pp.2512-2520
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• 1997

ITU-T Q.2931 and ATM Forum UNI 3.1 lead the standardization of signaling functions for the call/connection control at B-ISDN UNI. The one is applicable to the system in the public network, which provides the point-to-point call/connection control. The other is applicable to configure ATM private network mainly related with various terminal equipments. Domestic B-ISDN developers have developed ATM switches and B-NTs as network equipment, and B-TA as a terminal equipment. But many kinds of terminal-equipments are needed to provide various services in B-ISDN. If the public network can accommodate the terminal-equipments of UNI 3.1, it's very effective to accommodate manu kinds of terminal-equipments. Therefore, this paper identifies the problems that can be occurred on the signaling procedure, when B-ISDN the public network is connected to the UNI 3.1 terminal-equipment, and provides good alternatives that can handle this kind of call/connection well.

• Journal of KIISE:Computing Practices and Letters
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• v.6 no.1
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• pp.103-112
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• 2000

As today's market share of Intelligent Network (IN) service and wireless tele-communication is growing rapidly, the increment in service requests of wireless IN service subscribers and users has to be taken into account for implementing advanced IN services. In this paper, we design Global Service Logic for IN Freephone service, which is one of the commercially most interesting IN services, applied call queuing service feature with mass call processing to enhance call completion rate by considering the mobility of wireless service subscribers with mobile terminals as well as existing wireline service subscribers. Due to the location management of each IN subscribers 'mobile terminals, we design the structure and operation mechanism of Queue Manager which adjusts dynamically service subscribers groups according to their mobility. We optimize the queue size according to the call attempt rate and drop rate, and present the appropriate waiting time in the queue.

• Journal of Information Technology Services
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• v.19 no.6
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• pp.55-82
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• 2020

This study examined the factors that influence the turnover intention, job performance of call center representatives based on the adaptive structuration theory (AST). This study intended to empirically examine how individual characteristics of representative affect the technological and task adaptation, how they affect job performance and turnover intention. On the other hand, this study also explains how rational culture and organization a reputation which are considered as dimensions of organizational characteristics affects organizational commitment, and verifies the relationship between organizational commitment and job performance and turnover intention. Finally this paper aim to provide academic and practical implications. In order to solve the above research problems, this research proposed a model based on the adaptive structuration theory. In order to identify the relationship between the proposed variables and the AST for individual, we conducted an empirical test on the call center representatives. The structural equation model was used to verify the research model and hypotheses. The results of the empirical analysis show that the personal characteristics of counselors, such as communication skills, multitasking abilities, and innovativeness have a positive effect on skill adaptation, and skill adaptation has a positive effect on task adaptation, furthermore, it influences on job performance and turnover intention Respectively. In addition, among the factors of organizational environmental dimensions of the call center, it was found that organizational reputation not only increase continuance commitment but also increase normative commitment. Contrary to our expectations, perceived rational culture didn't have a positive effect on organizational commitment. Also, continuance commitment and normative commitment are valid predictors of job performance, but they have nothing to do with turnover intention. On the contrary, emotional commitment is the only one variable among three dimensions of organizational commitment have a positive effect on turnover intention, but is not a valid predictor of job performance.

• Honam Mathematical Journal
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• v.23 no.1
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• pp.59-66
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• 2001

A class of topological algebras, which we call it a fundamental one, has already been introduced to generalize the locally bounded and locally convex algebras. To prove the basic theorems on fundamental algebras, the first successful step is the new version of the Cohen factorization theorem. Here we recall it and prove some new results on fundamental topological algebras.