• The Journal of the Acoustical Society of Korea
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• v.10 no.1
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• pp.20-29
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• 1991

A fundamental assumption in conventional linear predictive coding (LPC) analysis procedure is that the input to an all-pole vocal tract filter is white process. In the case of periodic inputs, however, a pitch bias error is introduced into the conventional LP coefficient. Multi-pulse (MP) LP analysis can reduce this bias, provided that an estimate of the excitation is available. Since the prediction error of conventional LP analysis can be modeled as the sum of an MP excitation sequence and a random noise sequence, we can view extracting MP sequences from the prediction error as a classical detection and estimation problem. In this paper, we propose an algorithm in which the locations and amplitudes of the MP sequences are first obtained by applying a likelihood ratio test (LRT) to the prediction error, and LP coefficients free of pitch bias are then obtained from the MP sequences. To verify the performance enhancement, we iterate the above procedure with adaptive threshold at each step.

• Journal of Korean Library and Information Science Society
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• v.18
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• pp.139-192
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• 1991

Though the computer has become deeply entrenched as the major tool in information processing(library works), it may be obvious that automatic book classification techniques ate still under experimentation, and the techniques have not yet been tested against the criterion of usefulness. The purpose of this study is to design of knowledge base for automatic book classification which can be put to use in library operation, and to present a methodology of application of the automatic classification into the library. Since the enumerative classification schemes which are existing are manual systems, it cannot be applied to the automatic classification, the principle of faceted classification based on concept analysis is brought in and studied. The result of this study are summarized as follows : 1. The design of knowledge base confined the field of agriculture and medicine. 2. If title is entered by the computer keyboard it will be searched in knowledge base, and then be classified by the principle of automatic classification. 3. Program flowcharts are designed as a bases of classification procedures for automatic subject recognition and classification. 4. 283 books in agriculture, 196 books in medicine were drawn at random from Taegu University Library and Young-Nal Medical Center Library respectively. 5. The experiment of automatic classification is performed 143 books in agriculture 166 books in medicine except for other subject books. 6. It was proved that automatic book classification is possible by design of knowledge base. In addition the expected values from design of knowledge base for automatic book classification are as follows : 1. The prompt and accurate process of classification is possible. 2. Though some title is classified in any library, it can be classified the some classification number by a program. 3. The user can retrieve the classification codes of books for which he or she wants to search through the computer. 4. Since the concept coordination method is employed the representing of a multisubject concept is make simple. 5. By performing automatic book classification the automation of total system can be achieved. 6. The efficient international information transfer will be advanced since all the institution maintain unified classification number.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.5
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• pp.951-959
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• 2001

Video database has the function that stores videos and retrieves the video informations for the service request of users. Therefore, the purpose of the video database is to provide not only an environment both convenient and efficient for retrieving and storing video, but also to serve the requested video informations with rapid startup latency for more users. But, some users of video database as VOD application might tolerate slow startup latency because they would watch video during one hour or two hours. In this paper, we propose the novel policy of the storage system of video database, which serves efficiently the users by considering the classes of the users in video database. The policy admits the random movements of disk heads for urgent user classes but maintains the sequential or restricted movements of disk heads for less-urgent user classes like VOD application in storage system of video database. So, it can not provide only rapid startup latencies for urgent requests but also it can process more service requests in all.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.4
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• pp.867-875
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• 2014

Rapid development of internet service is enabling internet banking services in anywhere and anytime. However, service access through internet can be exposed to adversary easily. To prevent, current service providers execute authentication process with user's identification and password. However, majority of users use short and simple password and do not periodically change their password. As a result of this, user's password could be exposed to attacker's brute force attack. In this paper, we presented enhanced password system which guarantee higher security even though users do not change their current password. The method uses additional secret information to replace real password periodically without replacement of real password.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.10 no.6
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• pp.81-87
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• 2015

The purpose of this study is to explore the relationships among CSR activities, relationship quality, and organizational performance in an exclusive Liquor licensed Wholesalers in Korea. In this research, CSR activities consists of four factors including characterizes(consumer, economy, philanthropy, and environment). First, this study investigated how CSR activities affected both Honesty Trust and Reciprocity Trust, second analyzed how both Honesty Trust and Reciprocity Trust influenced organizational performance. The data were obtained from a questionnaire handed out to a random sample of 95 individuals that exclusive license operators. With the information obtained, and after the scales validation process, PLS(Partial Least Square) has been conducted. The analysis results indicate that CSR activities, relationship quality, and organizational performance in an exclusive license operators. According to the analysis, first, both economy and environment affect both Honesty Trust and Reciprocity Trust. second Honesty Trust affect organizational performance. Finally, based in the findings of this study, theoretical contribution and managerial implications are discussed.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.373-373
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• 2014

Resistive-change random access memory (ReRAM) device is one of the promising candidates owing to its simple structure, high scalability potential and low power operation. Many resistive switching devices using transition metal oxides materials such as NiO, Al2O3, ZnO, HfO2, $TiO_2$, have attracting increased attention in recent years as the next-generation nonvolatile memory. Among various transition metal oxides materials, HfO2 has been adopted as the gate dielectric in advanced Si devices. For this reason, it is advantageous to develop an HfO2-based ReRAM devices to leverage its compatibility with Si. However, the annealing temperature of these high-k thin films for a suitable resistive memory switching is high, so there are several reports for low temperature process including microwave irradiation. In this paper, we demonstrate the bipolar resistive switching characteristics in the microwave irradiation annealing processed Ag/HfO2/Pt ReRAM device. Compared to the as-deposited Ag/HfO2/Pt device, highly improved uniformity of resistance values and operating voltage were obtained from the micro wave annealing processed HfO2 ReRAM device. In addition, a stable DC endurance (>100 cycles) and a high data retention (>104 sec) were achieved.

• Korean Journal of Materials Research
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• v.20 no.5
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• pp.257-261
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• 2010

A non-volatile resistive random access memory (RRAM) device with a Cr-doped $SrZrO_3/SrRuO_3$ bottom electrode heterostructure was fabricated on $SrTiO_3$ substrates using pulsed laser deposition. During the deposition process, the substrate temperature was $650^{\circ}C$ and the variable ambient oxygen pressure had a range of 50-250 mTorr. The sensitive dependences of the film structure on the processing oxygen pressure are important in controlling the bistable resistive switching of the Cr-doped $SrZrO_3$ film. Therefore, oxygen pressure plays a crucial role in determining electrical properties and film growth characteristics such as various microstructural defects and crystallization. Inside, the microstructure and crystallinity of the Cr-doped $SrZrO_3$ film by oxygen pressure were strong effects on the set, reset switching voltage of the Cr-doped $SrZrO_3$. The bistable switching is related to the defects and controls their number and structure. Therefore, the relation of defects generated and resistive switching behavior by oxygen pressure change will be discussed. We found that deposition conditions and ambient oxygen pressure highly affect the switching behavior. It is suggested that the interface between the top electrode and Cr-doped $SrZrO_3$ perovskite plays an important role in the resistive switching behavior. From I-V characteristics, a typical ON state resistance of $100-200\;{\Omega}$ and a typical OFF state resistance of $1-2\;k{\Omega}$, were observed. These transition metal-doped perovskite thin films can be used for memory device applications due to their high ON/OFF ratio, simple device structure, and non-volatility.

• Journal of the Institute of Convergence Signal Processing
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• v.14 no.1
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• pp.27-32
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• 2013

It plays an important role to detect the shape of an ellipse in many application areas of image processing. But it is very difficult to detect the ellipse in the real image because the noise was involved in the image, other objects obscured the ellipse or the ellipses were overlap with each other. In this paper, we extract the boundary (edge) to detect ellipse in the image and perform the grouping process in order to reduce amount of information. As a result, the speed of the ellipse detection was improved. Also in order to the ellipse detection, we selected the five ellipse parameters at random And then to select the optimal parameters of the ellipse, the linear least-squares approximation is applied. To verify the ellipse detection, RANSAC algorithm is applied. After the algorithm proposed in this study was implemented, the results applied to the real images showed an aocuracy of 75% and speed was very fast to compared with other researches. It mean that the proposed algorithm was valuable to detect the ellipses in the image.

• Journal of Welding and Joining
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• v.28 no.2
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• pp.84-90
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• 2010

Fillet welding accounts for about 80% of all constructing process of ship and ocean structure. T-joint is one of the typical shapes which are frequently reported to experience the fatigue damage when the marine structure meets the storm loads. The fatigue damage is affected by the magnitude of residual stresses on the weld. Recently, many shipping registers and design guidances have required that the fatigue strength assessment method should be compensated by the effect of the residual stress in case that the random loading or storm loading is applied to the marine vessels. This study suggests the computational procedure to analyze the residual stresses of T-joint specimen that is frequently reported to get damaged by the storm loading. Experiment by XRD as well as the 3-D computational welding model is presented in order to get the profile of residual stress. Throughout the comparison of experimental result with the computational result, the computational model was validated. Thereafter, characteristics of he residual stresses in the joint are discussed.

• Journal of Korea Society of Industrial Information Systems
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• v.25 no.1
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• pp.89-99
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• 2020

In this paper, we consider a dyadic server control policy that combines workload control and single vacation. Customer arrives at the system with Bernoulli process, waits until his or her turn, and then receives service on FCFS(First come first served) discipline. If there is no customer to serve in the system, the idle single server spends a vacation of discrete random variable V. If the total service times of the waiting customers at the end of vacation exceeds predetermined workload threshold D, the server starts service immediately, and if the total workload of the system at the end of the vacation is less than or equal to D, the server stands by until the workload exceeds threshold and becomes busy. For the discrete-time Geo/G/1 queueing system operated under this dyadic server control policy, an idle period is analyzed and the steady-state queue length distribution is derived in a form of generating function.