• International Journal of Internet, Broadcasting and Communication
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• v.15 no.1
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• pp.79-84
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• 2023

Due to the rapid performance improvement of smartphones, multitasking on mobile platforms has become an essential feature. Unlike traditional desktop or server environments, mobile applications are mostly interactive jobs where response time is important, and some applications are classified as real-time jobs with deadlines. When interactive and real-time jobs run concurrently, memory allocation between multitasking applications is a challenging issue as they have different time requirements. In this paper, we study how to allocate memory space when real-time and interactive jobs are simultaneously executed in a smartphone to meet the multitasking requirements between heterogeneous jobs. Specifically, we analyze the memory size required to satisfy the constraints of real-time jobs and present a new model for allocating memory space between heterogeneous multitasking jobs. Trace-driven simulations show that the proposed model provides reasonable performance for interactive jobs while guaranteeing the requirement of real-time jobs.

• Journal of The Korean Association For Science Education
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• v.20 no.1
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• pp.174-182
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• 2000

In this study, the effects of grouping by communication apprehension level in cooperative learning strategy applied to general science class and the difference between high and low communication apprehension levels were investigated. Three classes (N=112) were randomly assigned to two cooperative and one traditional learning groups. Students in two cooperative learning classes were grouped into homogeneous and heterogeneous groups with respect to their communication apprehension levels based on the test score of students' communication apprehension. After the instructions concerning the matter for 11 class hours, achievement, self-esteem, motivation to learn science. and student's perception to lack about communication ability and expectation about receiving help in cooperative learning processes were examined. Two-way ANOVA results revealed that there were no main and interactive effects in the scores of the achievement test. However, significant main effect of the treatment was found in the scores of the relevance and the satisfaction among four motivation sub-categories. In post-hoc comparison, the scores of the heterogeneous group were found to be significantly higher than those of the control group. For expectation about receiving help in cooperative learning processes, the scores of the heterogeneous group were significantly higher than those of the homogeneous group. Students in high communication apprehension level had significantly lower self-esteem and more perception to lack about communication ability than students in low level.

• KIISE Transactions on Computing Practices
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• v.23 no.4
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• pp.238-243
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• 2017

This paper presents a study regarding a systemic structure that forms a link between heterogeneous terminals and the WebRTC (Web real-time communication) based video-conferencing systems. This system consists of a WebRTC-based terminal, a signal server for the relaying of the necessary signals for media negotiations, an MCU provides an interworking interface for the heterogeneous terminal, and the heterogeneous terminals that interwork with the MCU. This technology enables the interoperability between the WebRTC-based video-conferencing solutions and the legacy devices. In addition to reducing the replacement costs regarding new-technology-based solutions, the existing legacy equipment enables the use of multiparty-conference, thereby increasing the use ability of the conferencing systems.

• Journal of the Institute of Convergence Signal Processing
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• v.17 no.1
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• pp.1-9
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• 2016

In this paper, for the improvement of quality of service(QoS) performance of heterogeneous networks, multi-cell scheduling is proposed. In order to implement the proposed algorithm, for the recognition of the impact on the throughput performance of users, macro-pico-cells that form distributed architecture were proposed. In operating heterogeneous networks, considering the centralized structure, a macro-RRH(Remote Radio Head) deployment scenario was proposed. For interference mitigation of the proposed system, by applying the optional sub-frame, through CQI(Channel Quality Indicator) measurement for each sub-frame period, constraint conditions were measured according to system situations. For the simplification, the pattern of the same ABS muting was assumed. In the above two multi-cell environments, the algorithm of high-speed load balancing maintenance was proposed.

• Journal of KIISE
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• v.42 no.1
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• pp.122-129
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• 2015

This paper proposes a method for providing the information about multimedia streams for telepresence services to heterogeneous services such as IMS (IP Multimedia Subsystem) and RTCWeb (Real-Time Communication in WEB-browsers). First of all, we design an interworking gateway for each service and suggest a procedure for providing the information about multimedia streams, which is defined by CLUE, a working group for standardization, to the heterogeneous services. We also apply the method of the actual CLUE information exchange and implement it in our experiment environment. Finally, we show that the proposed method can exchange more information than previous methods even though the media session re-establishment time is similar to legacy systems in terms of performance analysis. With the proposed method, the heterogeneous services can collect a variety of information about the telepresence service and use it according to user preference. In this way it provides rich multimedia streaming services for many areas.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.1
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• pp.49-57
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• 2019

The International Maritime Organization is developing a maritime safety system called eNavigation in order to effectively respond to accidents occurring on board vessels. Korea is actively participating in the development of eNavigation and is developing Korean eNavigation by adding its own concept to eNavigation of the IMO. eNavigation is designed to provide various functions for marine safety. The data required for each function is various such as spatial data, relational data, file, weather grid. Therefore, there is a need for a system that can appropriately provide heterogeneous data suitable for eNavigation to each eNavigation's service system. In this paper, we analyzed the kinds of data needed for e-Navigation and designed the architecture of heterogeneous data service system that could provide these data properly.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.7
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• pp.622-626
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• 2012

This paper presents synchronization of LTV (Linear Time-Varying) MAS (Multi-Agent Systems) with heterogeneous time-varying disturbances under a fixed, connected, and undirected communication network. All the agents can collect only relative state information from their neighborhoods. To achieve synchronization of the MAS, an integral control scheme is proposed based on relative state information between agents.

• ETRI Journal
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• v.30 no.5
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• pp.696-706
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• 2008

With the increasing need for intelligent environment monitoring applications and the decreasing cost of manufacturing sensor devices, it is likely that a wide variety of sensor networks will be deployed in the near future. In this environment, the way to access heterogeneous sensor networks and the way to integrate various sensor data are very important. This paper proposes the common system for middleware of sensor networks (COSMOS), which provides integrated data processing over multiple heterogeneous sensor networks based on sensor network abstraction called the sensor network common interface. Specifically, this paper introduces the sensor network common interface which defines a standardized communication protocol and message formats used between the COSMOS and sensor networks.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.7
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• pp.1802-1814
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• 2012

In order to guide users to select the most optimal access network in heterogeneous wireless networks, a network selection algorithm is proposed which is designed based on multi-objective discrete particle swarm optimization (Multi-Objective Discrete Particle Swarm Optimization, MODPSO). The proposed algorithm keeps fast convergence speed and strong adaptability features of the particle swarm optimization. In addition, it updates an elite set to achieve multi-objective decision-making. Meanwhile, a mutation operator is adopted to make the algorithm converge to the global optimal. Simulation results show that compared to the single-objective algorithm, the proposed algorithm can obtain the optimal combination performance and take into account both the network state and the user preferences.

• Journal of Korean Institute of Industrial Engineers
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• v.25 no.3
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• pp.351-359
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• 1999

We present a new approach to the analysis of mobile cellular communication systems under the environment of mixed platforms adopting a guard channel scheme. We assume general cell residence time distributions according to platform-types. Our system model is based on a heterogeneous M/G/c loss system with customer-dependent guard channels, where heterogeneous customers with different service time distributions have different numbers of their own guard channels. We develop the general formula of steady state probabilities for the heterogeneous M/G/c loss system with customer-dependent guard channels. The mean channel occupancy times of new and handoff calls are rigorously derived under a general setting. Finally, our numerical results show that the blocking probability and the forced termination probability are sensitive to the cell residence time distributions.