• IE interfaces
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• v.11 no.1
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• pp.155-163
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• 1998

In multiparty multimedia communication, each participant not only receives information from other participants but also generates real-time data streams to distribute to others and therefore the difference between source and destination is not clear in terms of data transmission. During a teleconference session, many sub-multicast trees may be generated to exchange information to specific members within the multicast group and if those sub-multicast trees use the same fixed multicast tree, the blocking probability will be high and it is hard to provide QoS for each sub-multicast group. Also, even though there exits some shortcuts between each sub-multicast group, fixed multicast tree does not allow to use those shortcuts. Thus to overcome these problems. We propose a network resource reservation protocol and show that its effectiveness in terms of blocking probability and network resources usage.

• Bulletin of the Korean Chemical Society
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• v.24 no.7
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• pp.906-910
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• 2003

Hydrothermal reactions of Ni(NO₃)₂· 6H₂O with trans-1,2-bis(4-pyridyl)ethylene (bipyen), in the presence of a linear 2,6-naphthalene dicarboxylic acid (NDCH₂) and a bent 4,4'-oxybis(benzoic acid) (OBCH₂), gave a 2-D coordination polymer [Ni(NDC)(bipyen)(H₂O)] (1) and also a 2-D coordination polymer [Ni(OBC)(bipyen)]· H₂O (2), respectively. A reversible de-coordination and re-coordination of an aqua ligand was observed for polymer 1. Polymer 2 has an undulated 2-D network based on 50-membered rectangular grids, each of which has the dimension of 13.61 × 13.17 Å.

• Journal of Korea Multimedia Society
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• v.22 no.10
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• pp.1187-1198
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• 2019

In this study, we propose a new $PM_{10}$ forecasting model for Seoul region using DNN(Deep Neural Network) and secondary data. The previous numerical and Julian forecast model have been developed using primary data such as weather and air quality measurements. These models give excellent results for accuracy and false alarms, but POD is not good for the daily life usage. To solve this problem, we develop four secondary factors composed with primary data, which reflect the correlations between primary factors and high $PM_{10}$ concentrations. The proposed 4 models are A(Anomaly), BT(Back trajectory), CB(Contribution), CS(Cosine similarity), and ALL(model using all 4 secondary data). Among them, model ALL shows the best performance in all indicators, especially the PODs are improved.

• Korean System Dynamics Review
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• v.12 no.2
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• pp.69-94
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• 2011

Daejeon, encompassing Daedeok Science Town and Daedeok Innopolis, possesses the advantage of portraying relatively higher regional innovation capacity and facilitating network formation among regional professional research organizations. Applying the Social Network Analysis(SNA) techniques, this paper focuses on divulging structural and spatial characteristics of the Daejeon Information and Communication(ICT) industry network, analyzing co-research projects implemented by the Daejeon-based universities. For the analytical tool, it depends on NETMINER 3.0. Furthermore, based on the Systems Thinking approaches, this study suggests a couple of policy implications. Judging from the Korea Standard Industrial Classification principles, the existing ICT industry is subdivided into 11 sub-industries. The highest degree centralization value comes from the Mobile Communication sub-industry(188.668%), indicating that Mobile Communication sub-industry exerts the most significant impact on the regional innovation networking in Daejeon. Among various stakeholders, Korea Advanced Institute of Science and Technology(KAIST) records the top ranking in most categories, conspicuously leading the institute-industry linkage. In terms of the ICT spatial distribution, the intra-regional cooperation examples present the strongest linkage values, followed by Daejeon-the Capital Region ones. Finally, as well shown in a series of causal loop analyses, this study recommends that Daejeon should put top policy priority in strengthening the internal ICT network within Daejeon proper. Here, Daejeon should keep in mind the fact that there exist reinforcing loops between Daejeon's attractiveness and the entering of new ICT firms.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.123-131
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• 2012

As the price of traditional fuels soar, the alternatives are becoming more viable. And manufacturers are promoting the growing viability of electric and biofuel-powered vehicles through longer warranties. Now, these longer green environment (emission)warranties, sometimes called extended warranties or "super warranties," have been adapted. The main result of this paper is to present a new method to approximate a bivariate warranty function by using Radial Basis Function Network with application of Radon Transform and its inverse which is used to reduce the dimension of the warranty space. This method consist of the following stages: First, by using the Radon Transform, the bivariate warranty function can be reduced to one dimensional function. Second, each of the one dimensional functions is approximated by using neural network technique into neural sub-networks. Third, these neural sub-networks are combined together to form the final approximation neural network. Four, by using the inverse of radon transform to this final approximation neural network we get the approximation to the given function. Also, we apply the above method to some green warranty data of automotive vehicle company.

• Journal of the Korean Magnetics Society
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• v.19 no.2
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• pp.62-66
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• 2009

The soft magnetic FeSiCr were processed the ball-mill for 30 hours and the shape of FeSiCr particles was changed from sphere to flake type, which was observed using scanning electron microscope. The complex permittivity and permeability spectra and reflection loss of FeSiCr-rubber composite was measured using Network Analyzer in order to investigate the relationship between the microwave absorption and the material constants. The matching frequency shifted toward lower frequency range with microwave absorber thickness, and microwave absorber with FeSiCr-rubber composite showed a maxium reflection loss of -8.3 dB at 1.86 GHz for a 1.3 mm thickness.

• International Journal of Computer Science & Network Security
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• v.21 no.9
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• pp.339-345
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• 2021

The rapid development of various applications in networking system, business, medical, education, and other domains that use basic data access operations such as insert, edit, delete and search makes data structure venerable and crucial in providing an efficient method for day to day operations of those numerous applications. One of the major problems of those applications is achieving constant time to search a key from a collection. A number of different methods which attempt to achieve that have been discovered by researchers over the years with different performance behaviors. This work evaluated these methods, and found out that almost all the existing methods have non-constant time for adding and searching a key. In this work, we designed a multi-indexes hashing algorithm that handles a collision in a hash table T efficiently and achieved constant time O(1) for searching and adding a key. Our method employed two-level of hashing which uses pattern extraction h₁(key) and h₂(key). The second hash function h₂(key) is use for handling collision in T. Here, we eliminated the wasted slots in the search space T which is another problem associated with the existing methods.

• New & Renewable Energy
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• v.18 no.1
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• pp.35-45
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• 2022

The renewable energy based MG is becoming one of the prominent solutions for greenhouse gas and constructing less power lines. However, how to procure the economics of MG considering the CO₂ emission and utility network impact is one of major issues as the proportion of renewable resource increases. This paper proposes the feasibility study scheme of campus MG and shows that the LCOE and CO₂ emission can be reduced by utilizing the excess power and introducing hydrogen system and plus DR. For this, the three cases: (a) adding the PV and selling excess power to utility, (b) producing and selling hydrogen using excess power, and (c) participating in plus DR are considered. For each case, not only the topology and component capacity of MG to secure economic feasibility, but also CO₂ emission and utility network effects are derived. If an electrolyzer with a capacity of 400 kW participates in plus DR for 3,730hours/year, the economic feasibility is securable if plus DR settlement and hydrogen sale price are more than 7.08¢/kWh and 8.3USD/kg or 6.25¢/kWh and 8.6USD/kg, respectively. For this end, continuous technical development and policy support for hydrogen system and plus DR are required.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.1
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• pp.65-73
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• 2007

Pattern classification of single and multiple discharge sources was applied using a wavelet image signal method in which a feature extraction was applied using a hidden sub-image. A feature extracting method that used vertical and horizontal images using an MSD method was applied to an averaging process for the scale of pulses for the phase. A feature extracting process for the preprocessing of the input of a neural network was performed using an inverse transformation of the horizontal, vertical, and diagonal sub-images. A back propagation algorithm in a neural network was used to classify defective signals. An algorithm for wavelet image processing was developed. In addition, the defective signal was classified using the extracted value that was quantified for the input of a neural network.

• Journal of information and communication convergence engineering
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• v.6 no.4
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• pp.466-469
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• 2008

The existing routing protocols in USN environment, PEGASIS is more efficient than LEACH, which is a hierarchical routing protocol, for network configuration based on power consumption. Despite its merit that it can reduce energy consumption per node, however, the PEGASIS protocol also has a weakness that it is less responsive to frequent changes that occur in the configuration of sensor network due to BS nodes that keep changing, which is a typical characteristic of the sensor network. To address this problem, this paper proposes to select sub-cluster heads and have them serve as intermediate nodes. This paper presents and analyses that this method can resolve the aforementioned problem of the PEGASIS algorithm.