• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.12C
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• pp.1188-1193
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• 2007

This paper proposes a secure data forwarding scheme on source routing-based ad-hoc networks. The scheme uses two hash-key chains generated from a trusted third party to generate Message Authentication Codes for data integrity The selected MAC keys are delivered to the ad-hoc node using a pre-shared secret between the trusted third party and a node. The proposed scheme does not require the PKI, or the provisioning of the pre-shared secrets among the ad-hoc nodes.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.2
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• pp.193-204
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• 2010

Since Wireless Multimedia Sensor Network(WMSN) needs to process various multimedia data such as audio, image and video data as well as scalar data, it requires a mechanism that can support Quality of Service(QoS) to handle efficiently. This paper classifies traffic in WMSN as periodic monitoring traffic, event traffic, multimedia traffic and query-based traffic, proposes marking algorithm and queue management mechanism that guarantee differentiated QoS in terms of delay, energy efficiency and credibility on each traffic and conduct performance analysis with simulation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.8
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• pp.2801-2815
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• 2022

With the advent and realization of Software Defined Network (SDN) architecture, many organizations are now shifting towards this paradigm. SDN brings more control, higher scalability, and serene elasticity. The SDN spontaneously changes the network configuration according to the dynamic network requirements inside the constrained environments. Therefore, a monitoring system that can monitor the physical and virtual entities is needed to operate this type of network technology with high efficiency and proficiency. In this manuscript, we propose a real-time monitoring system for data collection and visualization that includes the Prometheus, node exporter, and Grafana. A node exporter is configured on the physical devices to collect the physical and virtual entities resources utilization logs. A real-time Prometheus database is configured to collect and store the data from all the exporters. Furthermore, the Grafana is affixed with Prometheus to visualize the current network status and device provisioning. A monitoring system is deployed on the physical infrastructure of the KOREN topology. Data collected by the monitoring system is further pre-processed and restructured into a dataset. A monitoring system is further enhanced by including machine learning techniques applied on the formatted datasets to identify the elephant flows. Additionally, a Random Forest is trained on our generated labeled datasets, and the classification models' performance are verified using accuracy metrics.

• IEIE Transactions on Smart Processing and Computing
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• v.1 no.3
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• pp.182-191
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• 2012

This paper proposes a high performance QoS (Quality of Service) traffic transmission scheme to provide real-time multimedia services in wireless networks. This scheme is based on both a traffic estimation of the mean rate and a header compression method by dividing this network model into two parts, core RTP/UDP/IP network and wireless access parts, using the IEEE 802.11 WLAN. The improvement achieved by the scheme means that it can be designed to include a means of provisioning the high performance QoS strategy according to the requirements of each particular traffic flow by adapting the header compression for real-time multimedia data. A performance evaluation was carried out to show the effectiveness of the proposed traffic transmission scheme.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.229-232
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• 1998

Modern telecommunications are increasingly demanding the addition of complex switching features to switching system software. These improvements also should satisfy customer demands for quick provisioning of new service features. But whenever we have developed the switching system in various types, we met problems that are lack of system engineers and short developments terms. We need new guidelines of software design to meet the demands and overcome our problems. So we propose new software platform, scenario driven call control engine (SDCCE) for ATM switching system software and implement an effective call control software using scenarios for ATM Switching System. A scenario is a set of procedures and supplementary scenarios written in data structure and gives benefits to easy adapt new or modified function by adding a scenario. The goal of SDCCE is to increase reusability and readability of software. Especially, it gives a good software extensibility and maintainability. And when we developed ptmp call processing control software, we could get high productivity by reusing scenarios and procedures of ptp call processing control software. We applied the scenario driven call control software to ATM switching system.

• Industrial Engineering and Management Systems
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• v.16 no.1
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• pp.52-63
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• 2017

The inventory level of concurrent spare parts (CSP) has a significant impact on the availability of a weapon system. A failure rate function might be of particular importance in deciding the CSP inventory level. We developed a CSP optimization model which provides a compromise between purchase costs and shortage costs on the basis of the Weibull and the exponential failure rate functions, assuming that a failure occurs according to the (non-) homogeneous Poisson process. Computational experiments using the data obtained from the Korean Navy identified that, throughout the initial provisioning period, the optimization model using the exponential failure rate tended to overestimate the optimal CSP level, leading to higher purchase costs than the one using the Weibull failure rate. A Pareto optimality was conducted to find an optimal combination of these two failure rate functions as input parameters to the model, and this provides a practical solution for logistics managers.

• Journal of the Korea Society of Computer and Information
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• v.22 no.8
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• pp.25-32
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• 2017

In this paper we propose a resource management method which enables to guarantee the quality of experience (QoE) for handover in the overlaid macro-femtocell networks. How to cope with the resource demand of handover calls is necessary to efficiently support the movement of mobile terminals, the QoE degradation or the load control. We attempt to satisfy the QoE requirements of users and maximize the capacity of the system at the same time. In order to achieve this goal, this scheme divides the shared resources into two part for the movement of MT and QoE degradation, and allocates those resources with the competition between four types of handovers. Simulation results show that our scheme provides better performances than the conventional one with respect to the outage probability, data transmission throughput.

• Journal of the Korea Society of Computer and Information
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• v.20 no.10
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• pp.53-59
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• 2015

In this paper we propose a resource management scheme which allocates hierarchical resources stepwise based on the users' QoS requirement of each service in the macro-femtocell overlaid LTE-Advanced network. Our proposed scheme adjusts the transmission rate to the minimum which guarantees the allowable minimum requirement of delay for each user service. In this way it minimizes the interference on the adjacent channels and it is able to increase the resource utilization efficiency. Simulation results show that our scheme provides better performances than the conventional one in respect of the outage probability and data transmission throughput.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.5B
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• pp.334-343
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• 2008

In this work we propose a universal pricing machine, which incorporates a universal pricing framework for the future IEEE802.16 WiMAX service with multiple classes of service. A multimedia service is provided by a QoS provisioning scheme in the WiMAX network and universal pricing means that it can compute the price for any type of service in a unified framework. In the proposed pricing framework we incorporate multiple types of services such as the real time and nonreal time services that are supposed to be provided in the WiMAX network. To that purpose, let us first carry out an analysis on the current pricing scheme of Korean WiMAX service which incorporates only the data size. From that analysis we propose a new pricing scheme for the future WiMAX service that provides different service classes in the network. Via numerical experiment, we verify the implication of the work.

• International Journal of Computer Science & Network Security
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• v.22 no.4
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• pp.89-100
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• 2022

With the advancement in the Internet of things Technology (IoT) cloud computing, billions of physical devices have been interconnected for sharing and collecting data in different applications. Despite many advancements, some latency - specific application in the real world is not feasible due to existing constraints of IoT devices and distance between cloud and IoT devices. In order to address issues of latency sensitive applications, fog computing has been developed that involves the availability of computing and storage resources at the edge of the network near the IoT devices. However, fog computing suffers from many limitations such as heterogeneity, storage capabilities, processing capability, memory limitations etc. Therefore, it requires an adequate task scheduling method for utilizing computing resources optimally at the fog layer. This work presents a comprehensive review of different task scheduling methods in fog computing. It analyses different task scheduling methods developed for a fog computing environment in multiple dimensions and compares them to highlight the advantages and disadvantages of methods. Finally, it presents promising research directions for fellow researchers in the fog computing environment.