• Journal of the Korean Chemical Society
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• v.30 no.1
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• pp.3-8
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• 1986

The investigation of the effect of solvent structure on the first-order solvolysis of cis-$[Co(en)_2ClNO_2]^+$ion has been extended to water + co-solvent mixtures where the co-solvents are glycerol, ethylene glycol, isopropyl alcohol and t-butyl alcohol. Rates of solvolysis have been evaluated by spectrophotometric method at temperature 25∼30$^{\circ}$C. The polarity of solvent has influence on the variation of rate constant. The non-linear plot of the rate constant in log scale versus $\frac{D-1}{2D+1}$ implies that change in solvent structure with composition plays an important role in determining the variation of rate constant. The linearity of the plot of the rate constant in log scale versus the Grundwald-Winstein Y factor confirms that the solvolysis is an Id-type process with considerable extension of the metal chloride bond in the transition state. In the Kivinen equation the slope of the plot of log k versus $log(H_2O)$ suggests that the solvolysis is also an Id-type process. The application of free energy cycle shows that the effect of solvent structure is greater in the transition state than in the initial state.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.9
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• pp.1-7
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• 2008

The efficient node energy utilization in wireless sensor networks has been studied because sensor nodes operate with limited power based on battery. Since a large number of sensor nodes are densely deployed and collect data by cooperation in wireless sensor network, keeping more sensor nodes alive as possible is important to extend the lifetime of the sensor network. Energy efficiency is an important factor of researches that efficient routing algorithm is needed in wireless sensor network. In this research, I consider some methods to utilize more efficiently the limited power resource of wireless sensor networks. The proposed algorithm is the sink first divides the network into several areas with hop counts and data transmission based on cluster ID. The performance of the proposed algorithm has been examined and evaluated with NS-2 simulator in terms of lifetime, amount of data and overhead.

• Journal of the Korea Society of Computer and Information
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• v.14 no.2
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• pp.37-44
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• 2009

In this paper, we propose an efficient method which improves the performance of transmission of PGA which is essential data for real-time earthquake monitoring system. Currently, above 120 earthquake stations were installed nationwide and additional installation is expected because the social interesting of earthquake hazard is rising. Real-time earthquake monitoring system checks earthquake occurrence by using PGA were calculated from acceleration data of each seismic station. An efficient method of PGA data transmission is key factor of real-time monitoring. The key idea of proposed method is to deal with each seismic station using an unique ID, to assign one bit to indicate whether a packet include a station's data or not. Proposed method can contain more station data and decrease the data loss compared to current method. To verify proposed method, we investigate the turnaround time and ratio of data loss using above 91000 packets. As results of experiment. the proposed method is proven that the method need more time about 50% but reduce the data loss about 87% as compared to previous method.

• Journal of the Korean Home Economics Association
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• v.36 no.11
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• pp.119-128
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• 1998

This study was designed to find tendencies of housing value orientation of the model steel house visitors. Questionnaires were collected in June, 1997, 1,550 in total, 508 cases from Seoul, 456 cases from Pohang, and 486 cases from Kwangyang. Data were analyzed in terms of housing value orientation, using statistical methods including frequencies, mean, percentages, chi-square test and multiple regression. The major findings are as follows; 1. The subjects were highly educated(64% of them were college graduates) with the monthly income over 2,000,000won(approximately $1,540). The average monthy income of the subjects in Seoul, about 4,000,000won($3,070), was much higher than that of other areas. Most of the subjects were condominium owners(72%), who preferred single detatched houses or town houses located in suburban areas. 2. Differences in general tendencies among the three regional groups were statistically significant. Most significantly, subjects living in Pohang regarded the reputation of the building construction company most importnat. Subjects of all three regional areas, especially in Pohang, emphasized investment value. The price of the steel house was regarded as very important by all the groups tested. The housing value orientation was analyzed in 3 aspects; (1) Facility.Plumbing.Structure(FPS), (2) Interior space formation.Design(ID) and (3) Developmental complex.Near Environment(DN). Interior environment level, stability of house structure, and finighing state of interiors were identified as the important factors in the area of FPS(p<.05). The Interior plan organization was the most important factor among ID. As for DN, rated importantly were educational facilities, green areas, convenience of commercial facilities within the developmental complex were rated importantly.

• Journal of the Korea Computer Industry Society
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• v.4 no.4
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• pp.647-660
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• 2003

The present of state is situation that is realized by necessity of maintenance of public security about great many information is real condition been increasing continually in knowledge info-age been situating in wide field of national defense, public peace, banking, politics, education etc. Also, loss or forgetfulness, and peculation by ID for individual information and number increase of password in Internet called that is sea of information is resulting various social problem. By alternative about these problem, including Biometrics, several authentication systems through sign(Signature), Smart Card, Watermarking technology are developed. Therefore, This paper shows that extract factor that efficiency can get into peculiar feature in physical features for good fingerprint recognition algorithm implementation with old study finding that take advantage of special quality of these fingerprint.

• The KIPS Transactions:PartC
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• v.13C no.2 s.105
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• pp.161-166
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• 2006

In this paper, we propose optical subscriber access network to eliminate multiple access interference using 2 dimensional(D) optical frequency and time domain CDMA method. We have numerically analyzed the characteristics of proposed system. It is seen that the excess intensity noise is the major limiting factor to the system. Also it is seen that the number of simultaneous subscribers is four times as large as the conventional ID optical system under the same bit error ratio.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.9B
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• pp.1092-1097
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• 2011

An anti-collision protocol which tries to minimize the collision probability and identification time is the most important factor in all identification technologies. This paper focuses on methods to improve the efficiency of tag's process in identification systems. Our scheme, Binary Slotted Query Tree (BSQT) algorithm, is a memoryless protocol that identifies an object's ID more efficiently by removing the unnecessary prefixes of the traditional Query Tree (QT) algorithm. With enhanced QT algorithm, the reader will broadcast 1 bit and wait the response from the tags but the difference in this scheme is the reader will listen in 2 slots (slot 1 is for 0 bit Tags and slot 2 is for 1 bit Tags). Base on the responses the reader will decide next broadcasted bit. This will help for the reader to remove some unnecessary broadcasted bits which no tags will response. Numerical and simulation results show that the proposed scheme decreases the tag identification time by reducing the overall number of request.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.11
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• pp.1077-1082
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• 2016

IDS can be used as a countermeasure for malicious attacks which cause degrade of network transmission performance by disturbing of MANET routing function. In this paper, effects of IDS for transmission performance on MANET under grayhole attacks which has intrusion objects for a part of transmissions packets, some suggestion for effective IDS will be considered. Computer simulation based on NS-2 is used for performance analysis, performance is measured with VoIP(: Voice over Internet Protocol) as an application service. MOS(: Mean Opinion Score), CCR(: Call Connection Rate) and end-to-end delay is used for performance parameter as standard transmission quality factor for voice transmission.

• Journal of Welding and Joining
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• v.29 no.2
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• pp.64-71
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• 2011

In this paper, crack propagation analyses in the inner diameter (ID) repair weld of the dissimilar metal weldment of a nozzle were performed using a finite element alternating method (FEAM). To calculate the theoretical solution for the crack tip stress intensity factor, a weak type singular integral equation consisted of crack surface traction and dislocation density function was constructed and solved in conjunction with the FEAM. A two-dimensional axisymmetric finite element nozzle model was prepared and ID repair welding was simulated. An initial crack, 10% depth of weld thickness, was assumed and crack propagation trajectory from the initial crack to the 75% depth of thickness was calculated using the FEAM. Crack growth versus time curve was also calculated and compared with the curves obtained from ASME code method. With the method constructed in this paper, crack propagation trajectory and crack growth time were calculated automatically and effectively.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.267-270
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• 2017

As IT technology developed, storage media also developed. Among them, USB, which is a removable storage medium, is used not only to have several per person but also to work in various companies. Users store valuable and confidential data within USB. As time went on, the need for security increased. In order to solve this security problem, USB has been introduced to allow users to access internal files by inputting ID and password by embedding a security program in USB. However, the method of storing ID and Password inside is low confidentiality and high risk of information leakage. To solve these problems, we propose a 2 factor authentication system using Radius server in addition to login authentication. The proposed system not only improves the authenticity of the device, but also reduces the risk of infringement of personal information when lost. It also encrypts internal files to increase the confidentiality of internal information.