• Journal of KIISE:Databases
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• v.31 no.3
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• pp.297-306
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• 2004

Push-based broadcasting in wireless information services is a very effective technique to disseminate information to a massive number of clients when the number of data items is small. When the database is large, however, it nay be beneficial to integrate a pull-based (client-to-server) backchannel with the push-based broadcast approach, resulting in a hybrid data delivery. In this paper, we analyze the performance behavior of a predeclaration-based transaction processing, which was originally devised for a push-based data broadcast, in the hybrid data delivery through an extensive simulation. Our results show that the use of predeclaration-based transaction processing can provide significant performance improvement not only in a pure push data delivery, but also in a hybrid data delivery.

• Journal of Information Processing Systems
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• v.16 no.3
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• pp.599-611
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• 2020

With the application and promotion of biometric technology, biometrics has become more and more important to identity authentication. In order to ensure the privacy of the user, the biometrics cannot be stored or manipulated in plaintext. Aiming at this problem, this paper analyzes and summarizes the scheme and performance of the existing biometric authentication system, and proposes an iris-based ciphertext authentication system based on fully homomorphic encryption using the FV scheme. The implementation of the system is partly powered by Microsoft's SEAL (Simple Encrypted Arithmetic Library). The entire system can complete iris authentication without decrypting the iris feature template, and the database stores the homomorphic ciphertext of the iris feature template. Thus, there is no need to worry about the leakage of the iris feature template. At the same time, the system does not require a trusted center for authentication, and the authentication is completed on the server side directly using the one-time MAC authentication method. Tests have shown that when the system adopts an iris algorithm with a low depth of calculation circuit such as the Hamming distance comparison algorithm, it has good performance, which basically meets the requirements of real application scenarios.

• Journal of the Korea Computer Industry Society
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• v.9 no.2
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• pp.53-62
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• 2008

Intensive studies have been made in the area of IPTV VOD server. The basic goal of the study is to find an efficient mechanism to allow maximum number of users under the limited resources such as Buffer utilization, disk performance and network bandwidth. The overlay multicast that has been recently presented as an alternative for the IP multicast has been getting much persuasion by the system resource and the network bandwidth and the advancement of the network cost. we propose a efficient overlay multi_casting network policy for multimedia services with multi media partition storage. Simulation results show that the rate of service number and service time of proposed scheme are about 23% performance improved than that of traditional methods. This implies that our method can allow much more users for given resources.

• International journal of advanced smart convergence
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• v.10 no.4
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• pp.278-288
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• 2021

Recently, IoT systems are cloud-based, so that continuous and large amounts of data collected from sensor nodes are processed in the data server through the cloud. However, in the centralized configuration of large-scale cloud computing, computational processing must be performed at a physical location where data collection and processing take place, and the need for edge computers to reduce the network load of the cloud system is gradually expanding. In this paper, a cluster system consisting of 6 inexpensive Raspberry Pi boards was constructed to perform fast data processing. And we propose "Kubernetes cluster system(KCS)" for processing large data collection and analysis by model distribution and data pipeline method. To compare the performance of this study, an ensemble model of deep learning was built, and the accuracy, processing performance, and processing time through the proposed KCS system and model distribution were compared and analyzed. As a result, the ensemble model was excellent in accuracy, but the KCS implemented as a data pipeline proved to be superior in processing speed..

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.5
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• pp.1-8
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• 2019

Internet of Things (IoT) is proliferating to provide more intelligent services by interconnecting various Internet devices, and TCP based MQTT is being used as a standard communication protocol of the IoT. Although it is recommended to use TLS/SSL security protocol for TCP with MQTT-based IoT devices, encryption and decryption performance degenerates when applied to low-specification / low-capacity IoT devices. In this paper, we propose an end-to-end message security protocol using elliptic curve cryptosystem, a lightweight encryption algorithm, which improves performance on both sides of the client and server, based on the simulation of TLS/SSL and the proposed protocol.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.6
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• pp.2282-2303
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• 2021

To solve the problems of heavy computing load and system transmission pressure in energy internet (EI), we establish a three-tier cloud-edge integrated EI network based on a cloud-edge collaborative computing to achieve the tradeoff between energy consumption and the system delay. A joint optimization problem for resource allocation and task offloading in the threetier cloud-edge integrated EI network is formulated to minimize the total system cost under the constraints of the task scheduling binary variables of each sensor node, the maximum uplink transmit power of each sensor node, the limited computation capability of the sensor node and the maximum computation resource of each edge server, which is a Mixed Integer Non-linear Programming (MINLP) problem. To solve the problem, we propose a joint task offloading and resource allocation algorithm (JTOARA), which is decomposed into three subproblems including the uplink transmission power allocation sub-problem, the computation resource allocation sub-problem, and the offloading scheme selection subproblem. Then, the power allocation of each sensor node is achieved by bisection search algorithm, which has a fast convergence. While the computation resource allocation is derived by line optimization method and convex optimization theory. Finally, to achieve the optimal task offloading, we propose a cloud-edge collaborative computation offloading schemes based on game theory and prove the existence of Nash Equilibrium. The simulation results demonstrate that our proposed algorithm can improve output performance as comparing with the conventional algorithms, and its performance is close to the that of the enumerative algorithm.

• Journal of Wellbeing Management and Applied Psychology
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• v.6 no.2
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• pp.27-31
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• 2023

Purpose: Establishment of a real-time monitoring system for odor control in traditional markets in Gangwon-do and a system for linking prevention facilities. Research design, data and methodology: Build server and system logic based on data through real-time monitoring device (sensor-based). A temporary data generation program for deep learning is developed to develop a model for odor data. Results: A REST API was developed for using the model prediction service, and a test was performed to find an algorithm with high prediction probability and parameter values optimized for learning. In the deep learning algorithm for AI modeling development, Pandas was used for data analysis and processing, and TensorFlow V2 (keras) was used as the deep learning library. The activation function was swish, the performance of the model was optimized for Adam, the performance was measured with MSE, the model method was Functional API, and the model storage format was Sequential API (LSTM)/HDF5. Conclusions: The developed system has the potential to effectively monitor and manage odors in traditional markets. By utilizing real-time data, the system can provide timely alerts and facilitate preventive measures to control and mitigate odors. The AI modeling component enhances the system's predictive capabilities, allowing for proactive odor management.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.4
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• pp.227-235
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• 1993

In this paper, the development of a high performance flexible controller is described. The hardware of the controller, based on VME-bus, consists of four M68020 single-board computers (32-bit) with M68881 numerical coprocessors, two M68040 single board donputers, I/O devices (such as A/D and D/A converters, paraller I/O, encoder counters), and bus-to-bus adaptor. This software, written in C and based on X-window environment with Unix operating system, includes : text editor, compiler, downloader, and plotter running in a host computer for developing control program ; device drivers, scheduler, and mathemetical routines for the real time control purpose ; message passing, file server, source level debugger virtural terminal, etc. The hardware and software are structured so that the controller might have both flexibility and extensibility. In papallel to the controller, a three degrees of freedom kinematically redundant robot has been developed at the same time. The development of the same time. The development of the robot was undertaken in order to provide, on the one hand, a computationally intensive plant to which to apply the controller, and on the other hand a research tool in the field of kinematically redundant manipulator, which is, as such, an important area. By using the controller, dynamic control of the redundant manipulator was successfully experimented, showing the effectiveness and flexibility of the controller.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.31-32
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• 2022

Commercialized game engines help develop content and support various platforms, but there are performance differences depending on the function. In this paper, a VR video conferencing platform corresponding to source multi-use was implemented, and the connection delay time according to the type of game server engine and the number of platform users was measured. As a result of the measurement, the latency was the lowest at 22.146 msec when using the Amazon GameLift engine and with 2 users, and the latency was the highest at 27.007 msec when using the ProudNet engine and with 10 users.

• Journal of Advanced Navigation Technology
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• v.28 no.2
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• pp.210-215
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• 2024

With increasing automation in ships and the development of autonomous ships, an IPMS (Integrated Platform Management System) in ship needs to integrate and process large amounts of real-time data from various equipment operating on different operating systems. A ship IPMS simulator based on data distribution service (DDS) was developed and its performance was evaluated to handle data processing similar in real ship environment. Errors were monitored while 1,000 topics/sec were asynchronously published and subscribed from data acquisitive units (DAUs) and an IPMS server operating on different operating systems. Except for the loss of some topics during the initial 4 seconds, topics were received without an error thereafter. The developed simulator demonstrates the feasibility of using DDS to integrate various control systems using different operating systems in actual ships.