• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.2
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• pp.1-7
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• 2019

Recently, multimedia streaming service has been activated, and the demand for high-quality multimedia convergence contents services is predicted to increase significantly in the future. The issues of the increasing network load due to the rise of multimedia streaming traffic must be addressed in order to provide QoS guaranteed services. To do this, an efficient network resource management and mobility support technologies are needed through seamless mobility support for heterogeneous networks. Therefore, in this paper, an MIH technology was used to recognize the network situation information in advance and reduce packet loss due to handover delays, and an ACLMIH-FHPMIPv6 is designed that can provide an intelligent interface through introducing a hierarchical mobility management technique in FPMIPv6 integrated network.

• Journal of Advanced Navigation Technology
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• v.20 no.6
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• pp.595-603
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• 2016

In the Republic of Korea, the LTE-based public safety (PS-LTE) network is being built for the 700 MHz frequency band. However, the same bands are also assigned to the LTE-based high-speed railway (LTE-R) network. Therefore, it is essential to utilize the co-channel interference management schemes for the coexistence of two LTE networks in order to increase the system throughput and to reduce the user outage probability. In this paper, we focus on the downlink (DL) system for the coexistence of PS-LTE and LTE-R networks by considering non radio access network (RAN) sharing and LTE-R RAN sharing by PS-LTE users (UEs) to analyze the UE throughput. Moreover, we also utilize the cooperative communications schemes, such as coordinated multipoint (CoMP) for the coexistence of PS-LTE and LTE-R networks in order to reduce the UE outage probability. We categorize the coexistence of PS-LTE and LTE-R networks into four different scenarios, and evaluate the performance of each scenario by the important performance indexes, such as UE average throughput and UE outage probability.

• Journal of the Korean Institute of Landscape Architecture
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• v.49 no.2
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• pp.113-127
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• 2021

Although planning techniques linking parks, green areas, and waterways have become common, there are frequent disruptions in the operation and management of landscape-use artificial channels (LuAC). Therefore, this study examined a design to promote the sustainable management and operation of a LuAC using rainwater for the streamlets of the Jeonju-Wanju Innovative City. In order to accomplish the purpose of this study, scenarios were set up by dividing the design into waterhead and waterway portions. First, the scenario regarding the waterhead was analyzed to calculate the water supply and storage required for the waterway and waterhead. The analysis showed that the waterway requires a water supply of 676.8 tons/months, 3,018 tons to 5,512 tons of storage space, and a water depth of 0.75 m to 1.37 m considering the ecological and landscape aspects. The second scenario is to select an effective system of facilities for the operation and management of the LuAC. To accomplish this, a single-circulation system (SCS), which transports water to a highland location was compared to a multi-circulation system (MCS), which supplied water separately to each water space and operated independently. The results showed that the MCS, which was operated independently by small power units, was more effective owing to the vast difference in water supply operation times.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.9B
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• pp.745-750
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• 2008

In a cognitive radio based system, quality of service (QoS) for the secondary user must be maintained as much as possible even while that of the primary user is protected all he time. In particular, switching wireless links for the secondary user during the transmission of multimedia data causes delay and information loss, and QoS degradations occur inevitably. The efficient resource management scheme is necessary to support the seamless multimedia service to the secondary user. This paper proposes a novel frequency selection method based on Multi-Criteria Decision Making (MCDM), in which uncertain parameters such as received signal strength, cell load, data rate, and available bandwidth are considered during the decision process for the frequency selection with the fuzzy set theory. Through simulation, we show that our proposed frequency selection method provides a better performance than the conventional methods which consider the received signal strength only.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.44 no.3
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• pp.37-42
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• 2007

This paper reconsiders established power conservation models for ubiquitous sensor networks that use relay nodes instead of direct communication and proposes novel network power consumption model with consideration of the channel level and radio chip level simultaneously. We estimate the effect of minimum hop-count policy in terms of network power consumption through simulation of various situations for low power RF module CC2420. It is observed that maximum RF power and minimum hop-count results in lower energy consumption relatively. Also, in total network energy consumption, which is included re-transmission, minimum hop count policy presents decrease by 33.1% of energy consumption in compare with the conventional model.

• The Journal of the Korea Contents Association
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• v.8 no.4
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• pp.108-116
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• 2008

Recently the advent of web 2.0 era is an important trend in the business environmental change. Web 2.0 era means users' active participation, share, and openness, develop 'Internet penetration into everyday life,' and change many aspects of our society. web 2.0 has been making these following changes in the socioeconomic aspects: 1) acceleration of system shift to a small quantity of multi-species production system 2) growing influence of on-line channel/information to consumers 3) various minorities' power increase in the socioeconomic sector. web 2.0 has been making these following changes in the enterprise management: 1) the pursuit of open innovation from outside 2) active employment of viral marketing through Internet 3) the pursuit of present business transformation 4) strengthening of customer communication through open dialogue. Firms must squarely look at socioeconomic changes owing to web 2.0, and utilize them as business opportunities.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.7
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• pp.93-102
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• 2017

Recently increasing usage of smartphones makes the Internet of Things (IoT) a leading technology that can collect and share data through sensor networks and wireless communication such as low-power Bluetooth (BLE). BLE-based application can provide operators more precise information on Automatic Door system by remotely diagnosing the system faults through wireless sensor networks and sensors around the Automatic Door. In this paper, a smart device with extended BLE module is implemented which can monitor and Control the system states and faults remotely without on-site diagnostic. while maintaining system integrity so that increase efficiency of time and costs for system management. We can use the results of this research as a basis in evaluating reliability of data between devices, extending communication module in Controller of obsolete Door systems, and establishing centralized monitoring systems in near future with multi-channel Door Controls.

• Journal of KIISE
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• v.43 no.2
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• pp.256-268
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• 2016

Modern networks consisting of various heterogeneous equipment are often installed in a distributed manner. Thus the NETCONF standard was established to manage networks centrally and efficiently. In this paper, we present a method that integrates each NETCONF layer into a single system based on the results of previous studies. In the RPC Layer, an asynchronous communication channel and parallel processes are possible using multi-threading. In the Operation Layer, operational efficiency is increased by using a data group with dependencies between the equipment configuration data and by improving the data structure, enabling efficiently processing of XML queries even with multiple managers. The data modeling techniques and grouping methods in the Content Layer are presented in detail for interoperability between the Operation Layer and the Content Layer. Finally, the GUI program was implemented and its implementation is reported. We performed an experiment comparing the improved NETCONF with the standard NETCONF to measure factors, such as query processing ratio, query processing speed, and CPU utilization. The improved NETCONF demonstrated excellent query processing ratio and query processing speed, whereas the standard NETCONF had excellent CPU utilization.

• Journal of Korea Water Resources Association
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• v.52 no.6
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• pp.397-409
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• 2019

Gate operation of hydraulic structures is important for proper management in rivers. In this study, the characteristics of flood time were analyzed and predicted using the HEC-RAS model, which is capable of one-dimensional and two-dimensional connectivity analysis of the main points downstream of the Geum river. As a result, flood travel time was decreased once discharge increase and downstream water level rising. However, When the floodplain was overflowed, the arrival time increased due to the rapid increase of the river width. Also, the same condition, flood wave travel time at the major point was approximately twice as fast as water level rising travel time, indicating that waves progressed faster than actually water. Using the results of this study, it will be helpful in the river.

• Nuclear Engineering and Technology
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• v.54 no.3
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• pp.1062-1070
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• 2022

In the present communication, pure and stable α-Bismuth Oxide (Bi₂O₃) nanoparticles (NPs) were synthesized by low temperature solution combustion method using urea as a fuel and calcined at 500℃. The synthesized sample was characterized by using powder X-ray Diffraction (PXRD), Scanning Electron Microscopy (SEM), Energy dispersive X-ray analysis (EDAX), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR) and UV-Visible absorption spectroscopy. The PXRD pattern confirms the formation of mono-clinic, stable and low temperature phase α-Bi₂O₃. The direct optical energy band gap was estimated by using Wood and Tauc's relation which was found to be 2.81 eV. The characterized sample was studied for X-ray/gamma ray shielding properties in the energy range 0.081-1.332 MeV using NaI (Tl) detector and multi channel analyzer (MCA). The measured shielding parameters agrees well with the theory, whereas, slight deviation up to 20% is observed below 356 keV. This deviation is mainly due to the influence of atomic size of the target medium. Furthermore an accurate theory is necessary to explain the interaction of X-ray/gamma ray with the NPs.The present work opens new window to use this facile, economical, efficient, low temperature method to synthesize nanomaterials for X-ray/gamma ray shielding purpose.