• Journal of Korea Society of Digital Industry and Information Management
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• v.6 no.4
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• pp.95-105
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• 2010

DNS(Domain Name System) is a huge distributed database that converts host name to IP address. We are expecting the importance of DNS is more increased because many Internet application services appear according to the continuous increase of Internet users and nearly all the Internet application services use DNS. To prevent the interruption of DNS service, DNS server is configured with primary DNS server and a secondary DNS server which takes the place of primary DNS server in case of the service interruption. But this scheme is difficult for providing DNS service constantly in case of DDoS attack, which brings about much network load or network problems in DNS server group. Therefore, This paper proposed the scheme to locally distribute load of DNS server, and the use of address system to group the distributed DNS servers. Also, it proposed the authentication scheme of the correspondent server in case the server is changed in DNS server group having grouping address. In this paper, it is shown that the prosed scheme guarantees the improved service reliability with maintaining the present service performance through the evaluation. Through this, we can expect the high improved DNS service can be provided in the Internet environment in the future.

• International Journal of Computer Science & Network Security
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• v.21 no.4
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• pp.313-324
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• 2021

This study empirically investigates the factors influencing the intention to accept mobile technology in Saudi healthcare service delivery using the extended unified theory of acceptance and use of technology model (UTAUT) with perceived reliability and price value. Accordingly, a conceptual model combining behavioral constructs with those linked to the technology acceptance model is developed. This model aims to identify factors that predict patients' acceptance of mobile technology healthcare service delivery. The developed model is examined using responses obtained from a survey on 545 participants receiving healthcare services in Saudi Arabia. Thus, we have conceptualized the developed model and validated seven hypotheses involving key constructs. Results suggest that performance expectancy, effort expectancy, social influence, facilitating conditions, price value, and perceived reliability are direct predictors of user behavior to accept mobile technology in healthcare service delivery. The results provide empirical evidence to the literature on the effect of facilitating conditions and effort expectancy on mobile health (mHealth) adoption. The results show that the COVID-19 pandemic has significantly increased the adoption of mHealth services in Saudi Arabia.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.51-56
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• 2006

Biases embedded in numerical weather precipitation forecasts by the RDAPS model was determined, quantified and corrected. The ultimate objective is to eventually enhance the reliability of reservoir operation by Korean Water Resources Corporation (KOWACO), which is based on precipitation-driven forecasts of stream flow. Statistical post-processing, so called MOS (Model Output Statistics) was applied to RDAPS to improve their performance. The Artificial Neural Nwetwork (ANN) model was applied for 4 cases of 'Probability of Precipitation (PoP) for wet and dry season' and 'Quantitative Precipitation Forecasts (QPF) for wet and dry season'. The reduction on the large systematic bias was especially remarkable. The performance of both networks may be improved by retraining, probably every month. In addition, it is expected that performance of the networks will improve once atmospheric profile data are incorporated in the analysis. The key to the optimal performance of ANN is to have a large data set relevant to the predictand variable. The more complex the process to be modeled by the ANN, the larger the data set needs to be.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06d
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• pp.267-268
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• 2011

Recent research activities in cooperative communication focus on achieving energy efficiency and reliability. Relay selection strategy for cooperative communication improves the performance significantly. However, due to imbalance consumption of power, network might die earlier and more than 90% energy remains unused. In this paper, we provide a framework of an energy-efficient medium access control protocol that minimizes these problems and improves energy efficiency.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.465-466
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• 2009

This paper investigates congestion detection and control strategies for multi-path traffic (CDCM) diss emination in lifetime-constrained wireless sensor networks. CDCM jointly exploits packet arrival rate, succ essful packet delivery rate and current buffer status of a node to measure the congestion level. Our objec tive is to develop adaptive traffic rate update policies that can increase the reliability and the network lif etime. Our simulation results show that the proposed CDCM scheme provides with good performance.

• IEMEK Journal of Embedded Systems and Applications
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• v.1 no.2
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• pp.37-42
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• 2006

In this paper, we study a problem of providing reliable data transmission in wireless sensor network(WSN). A system with forward error correction9FEC) can provide an objective reliability while using less transmission power than a system without FEC. We propose the use of LDPC codes of various code rate (0.53, 0.81, 0.91) of FEC for WSN. Node-node-node interference is considered in the simulation in addition to AWGN in the channel. It is shown that the rate of 0.91 LDPC coded system obtained 7dB gain in signal to noise ratio over a system without FEC.

• Journal of Advanced Navigation Technology
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• v.26 no.6
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• pp.481-486
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• 2022

The recent rapid growth of the IoT(Internet of Things) is leading to the spread of low-power wireless technology. A major challenge in designing IoT wireless networks is to achieve coexistence between different wireless technologies that share the 2.4 [GHz] ISM (Industrial Scientific Medical) frequency band. Therefore, there is a need for research on improving the reliability of wireless networks and coexisting operation between wireless networks. In particular, it is necessary to study an interference model and performance for mutual service coexistence in a BLE (Bluetooth Low Energy) wireless network environment, which is expected to be widely used as a connection medium between devices in various industrial fields. In this paper, the co-channel interference model with the IEEE 802.15.4 system is established focusing on the physical layer of the BLE system widely used in residential and industrial wireless applications, and the performance of the BLE wireless communication system is analyzed in the co-channel interference environment. As a result of the analysis, as the distance between the interference source and the BLE system increases in an environment where noise and co-channel interference exist, the amount of co-channel interference decreases and the error rate performance of the BLE system improves.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.3
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• pp.545-553
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• 2017

This paper investigates a synchronization algorithm for a distributed network which does not have a centralized infrastructure. In order to operate a distributed network, synchronization across distributed terminals should be acquired in advance, and hence, a plenty of distributed synchronization algorithms have been studied extensively in the past. However, most of the previous studies focus on the synchronization only in fault-free networks. Thus, if there are some malfunctioning terminals in the network, the synchronization can not be guaranteed with conventional distributed synchronization methods. In this paper, we propose a reliability-based adaptive consensus algorithm which can effectively acquire the synchronization across distributed terminals and confirm performance of the proposed algorithm by conducting numerical simulations.

• International Journal of Computer Science & Network Security
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• v.21 no.8
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• pp.342-352
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• 2021

Multicast Routings is a big challenge due to limitations such as node power and bandwidth Mobile Ad-hoc Network (MANET). The path to be chosen from the source to the destination node requires protocols. Multicast protocols support group-oriented operations in a bandwidth-efficient way. While several protocols for multi-cast MANETs have been evolved, security remains a challenging problem. Consequently, MANET is required for high quality of service measures (QoS) such infrastructure and application to be identified. The goal of a MANETs QoS-aware protocol is to discover more optimal pathways between the network source/destination nodes and hence the QoS demands. It works by employing the optimization method to pick the route path with the emphasis on several QoS metrics. In this paper safe routing is guaranteed using the Secured Multicast Routing offered in MANET by utilizing the Ant Colony Optimization (ACO) technique to integrate the QOS-conscious route setup into the route selection. This implies that only the data transmission may select the way to meet the QoS limitations from source to destination. Furthermore, the track reliability is considered when selecting the best path between the source and destination nodes. For the optimization of the best path and its performance, the optimized algorithm called the micro artificial bee colony approach is chosen about the probabilistic ant routing technique.

• ETRI Journal
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• v.22 no.1
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• pp.1-11
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• 2000

The Satellite Operation System (SOS) has been developed for a low earth orbiting remote sensing satellite, Korea Multipurpose Satellite-I, to monitor and control the spacecraft as well as to perform the mission operation. SOS was designed to operate on UNIX in the HP workstations. In the design of SOS, flexibility, reliability, expandability and interoperability were the main objectives. In order to achieve these objectives, a CASE tool, a database management system, consultative committee for space data systems recommendation, and a real-time distributed processing middle-ware have been integrated into the system. A database driven structure was adopted as the baseline architecture for a generic machine-independent, mission specific database. Also a logical address based inter-process communication scheme was introduced for a distributed allocation of the network resources. Specifically, a hotstandby redundancy scheme was highlighted in the design seeking for higher system reliability and uninterrupted service required in a real-time fashion during the satellite passes. Through various tests, SOS had been verified its functional, performance, and inter-face requirements. Design, implementation, and testing of the SOS for KOMPSAT-I is presented in this paper.