• Journal of Korean Association for Spatial Structures
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• v.9 no.2
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• pp.45-52
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• 2009

This paper experimentally evaluates the strength characteristics of precast column-R.C. foundation anchor joint subjected to the cyclic horizontal load. The study presents differences in accurate stress transfer path and destruction mechanism between the concrete structural body applying the precast column-R.C. foundation anchor joint and the concrete structural body applying the steel joint. the result from width load experiment on reinforcing steel under the cyclic horizontal load provides the necessary minimum insertion length to construct the precast column-R.C. foundation anchor joint. This study also presents the accurate stress transfer path and destruction mechanism on the anchor joint th meet the customer's requirements, comparing stress transfer path and destruction mechanism provided by the experiment and those provided by the product manual. Eventually, this study presents all the necessary fundamental data to provide the construction design with accurate number of reinforcing steel, diameter of the steel, fixation length of the steel, etc. to build the optimum precast concrete column.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.12
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• pp.232-237
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• 2013

The role of the window length of time-frequency transformation is important for the audio data hiding methods utilizing phase information. In this paper, the experiments for our audio data hiding method were conducted in order to evaluate the audio quality and robustness against reverberant environment. The experimental results showed the tendency that the worse audio quality but better robustness were obtained when the lengthy window was applied. The important reason for quality degradation was pre-echo which flatters the percussive sound. The results also indicated that the wireless communication theory related to the length of time-frequency transform can be applied in the field of audio data hiding and acoustic data transmission.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.11
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• pp.30-40
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• 2001

In this paper, we propose a dynamic slot allocation algorithm for efficient transmission of VBR services in wireless ATM networks. The proposed algorithm is based on a hybrid dynamic parameter(DP) control which combines the strength of in-band control and out-of-band control by considering the variation characteristics of buffer length in distributed mobile terminals. This algorithm consists of four sub-algorithms: dynamic parameter determination algorithm, dynamic parameter transmission algorithm, estimation algorithm of the number of request slots, and prorated-allocation algorithm. As the proposed allocation algorithm based on the hybrid DP control scheme can offer nearly precise MAC level estimations of the requirements for each VBR, the algorithm makes it possible to obtain ideal allocation efficiency. The allocation efficiency of the algorithm is shown by numerical analysis. Simulation results show that the proposed algorithm has better performance than conventional schemes in terms of allocation efficiency, delay and cell loss ratio under VBR traffic.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.2
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• pp.217-221
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• 2012

As a part of basic research to improve screen quality, which deteriorates when strain occurs within optical sheets in LCD modules for laptop computers, a measurement system is needed to analyze the influence of heat and moisture, which are the main factors causing the strain. It is assumed that the existence of an air gap less of than 0.5 mm inside the LCD module causes humid air from outside to permeate through the module. To investigate this phenomenon, in this study a thin printed circuit board (PCB) of compact sensors that measure temperature and humidity is inserted into LCD modules, and thus, the changes in temperature and humidity can be analyzed in real time. The results can be used as basic data for simulation of the deformation behavior and structural design of LCD modules in the future.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.9
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• pp.837-845
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• 2013

An airlift pump can be used to pump liquids and sediments within itself, which cannot easily be pumped up by a conventional method, by using the airlift effect. This characteristic of the airlift pump can be exploited in a DCFC (Direct Carbon Fuel Cell) so that molten fuel with high temperature may be carried or transported. The basic characteristics of airlift are investigated. A simple system is constructed, where the reservoir is filled with water, a tube is inserted, and air is supplied from the bottom of the tube. Then, water is lifted and its flow rate is measured. Bubble patterns in the tube are observed in a range of air flow rates with the parameters of the tube diameter and submergence ratio, leading to four distinct regimes. The pumping performance is predicted, and the correlation between the supplied gas flow rate and the induced flow rate of water is found.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.512-515
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• 2003

MPEG-4 has mediocrity Standing encoding personality to process multimedia data including audio and video etc in the Internet and computer. It can use extensively without being limited to one territory of communication, computer, broadcasting, Mobile etc. Like this, according as digital contents do fetters to MPEG-4 is circulated, copyright problem was risen. So, people had a lot of interests to protect and manage copyright. Hereupon, MPEG of the ISO/IEC established IPMP(Intellectual Property Management and Protection) standard, and supplements and corrects continuously standard. Therefore, existing system does fetters to MPEG-4 need system that process IPMP information. Hereupon, in this paper, designed system module that is processed by IPMP extension standard that progress now, and embodied copyright protection and management system that user can insert and update IPMP information efficiently within whole or specification part of MPEG-4 digital contents.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.8B
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• pp.745-751
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• 2002

The performance of existing CDMA-type multiple access data transmission systems is limited by interferences due to adverse mobile communication channel characteristics. Among them, the multi-user interference becomes one of the major performance degradation factors because the signal-to-signal orthogonality can be easily perturbed when numerous user signals are distorted by multipath fading channels and mixed together. In order to enhance the performance of CDMA-type systems by suppressing the multi-user interference, we have adopted chip-based cyclic prefix insertion along with adaptive one-tap DFE equalization into MC-DS-CDMA, which is known for its robustness in the frequency selective multipath fading channel environment. In order to assess the performance of the proposed system, a set of computer simulations is performed in the reverse link in which each user signal undergoes different multipath Rayleigh fading. The results show us a superior performance of our system over other CDMA systems in terms of SNR to BER measurements.

• Journal of IKEEE
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• v.24 no.3
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• pp.791-796
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• 2020

In this paper, "Q-Bone", a 3^rd generation blockchain platform with enhanced security and flexibility, was developed. As a 3^rd generation blockchain platform, it exploits BP (block producer) to increase processing speed. It has many advantages as follows. It improves both security and speed by mixing RSA (Rivest-Shamir-Adleman) and AES (advanced encryption standard). It improves flexibility by exploiting gateway to convert between apps and blockchain with different programming language. It increases processing speed by combining whole transactions into one block and distribute it when too many transactions occur. It improves search speed by inserting sequence hash into transaction data. It was implemented and applied to pet communication service and academy-instructor-student matching service, and it was verified to work correctly and effectively. Its processing speed is 3,357 transactions/second, which shows excellent performance.

• Journal of the Korea Society of Computer and Information
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• v.12 no.4
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• pp.11-19
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• 2007

This paper proposes RCB(Reduced Compact Binary) tie to correct faults of both CB(Compact Binary) tie and HCB(Hierarchical Compact Binary) trie. First, in the case of CB trie, a compact structure was tried for the first time, but as the amount of data was increasing, that of inputted data gained and much difficulty was experienced in insertion due to the dummy nods used in balancing trees. On the other hand, if the HCB trie realized hierarchically, given certain depth to prevent the map from increasing on the right, reached the depth, the method for making new trees and connecting to them was used. Eventually, fast progress could be made in the inputting and searching speed, but this had a disadvantage of the storage space becoming bigger because of the use of dummy nods like CB trie and of many tree links. In the case of RCB trie in this thesis, the tree-map could be reduced by about 35% by completely cutting down dummy nods and the whole size by half, compared with the HCB trie.

• Journal of Korea Spatial Information System Society
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• v.7 no.2 s.14
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• pp.15-27
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• 2005

The purpose of this study is to present a methodology of GIS audit system which fully reflects standardization regarding GIS. With the recognition of the problems stemming from data exchange, building costs, and budget waste, this study utilized the standardization for evaluation factors of GIS audit. After analyzing the advantages and disadvantages of current audit methodology, this study pointed out the importance of audit, then presenting main audit factors followed by analyzing national standardization and extracting contents of audit to be added into the existing auditing items. Through the analysis of different types and characteristics, and both advantages and disadvantages of GASP, this study identifies and introduces a highly improved and practical methodology called Modified-GASP (M-GASP) that is basically set to be complementary and supplementary to GASP. Ultimately, the result of this study will support the higher degree of efficiency, stability, and extendability of GIS system, not to mention of strengthening the competitiveness of organizations involved.