• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.276.2-278
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• 2000

In a recent years, a number of approaches have been studied, including passive, active, and hybrid mode-locking of semi-conductor lasers for short pulse generation and research has been devoted to achieve low timing-jitter operation since the timing jitter is unfavorable for system applications. Among the methods of mode locking, passive mode locking does not need external rf drives, and therefore the operation and fabrication procedures are simplified. In spite of these attractive advantages of passive mode-locked laser, it has critical drawbacks such as large timing jitter and the difficulty in synchronization with external circuits. Their inherent large timing jitter value was shown to be suppressed to certain levels by means of hybrid mode-locking technique$^{(1)}$ , where the saturable absorber section was modulated by an external signal with the cavity round trip frequency. Furthermore, the subharmonic mode-locking (SHML) technique alleviates the restrictions of high speed driving electronics. It has been demonstrated experimentally$^{(1)}$ that the hybrid subharmonic mode-locking technique has lead to significant reduction of the timing jitter. (omitted)

• Journal of the Korean Society for Precision Engineering
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• v.28 no.3
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• pp.330-338
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• 2011

Odometry is the critical factor to estimate the location of the robot. In the mobile robot with wheels, odometry can be performed using the information from the encoder. However, the information of location in the encoder is inaccurate because of the errors caused by the wheel's alignment or slip. In general, visual odometer has been used to compensate for the kinetic errors of robot. In case of using the visual odometry under some robot system, the kinetic analysis is required for compensation of errors, which means that the conventional visual odometry cannot be easily applied to the implementation of the other type of the robot system. In this paper, the novel visual odometry, which employs only the single camera toward the ground, is proposed. The camera is mounted at the center of the bottom of the mobile robot. Feature points of the ground image are extracted by using median filter and color contrast filter. In addition, the linear and angular vectors of the mobile robot are calculated with feature points matching, and the visual odometry is performed by using these linear and angular vectors. The proposed odometry is verified through the experimental results of driving tests using the encoder and the new visual odometry.

• Proceedings of the Technology Innovation Conference
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• 2000.06a
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• pp.47-64
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• 2000

This paper analyses characteristics of the numerical controller industry in market formation and the Flow of information between users and producers and the characteristic of knowledge base of the industry and discusses the difficulties derived, from the characteristics, in accumulation of technological capability In market formation betweenusers and producers, the multi-layered market is not favorable to domestic producers in that lower end market is not large enough to provide cardle market to them which produce inferior quality and lower price than importer products. The credibility of the permance of a product is difficult to prove until a critical mass of products are sold. Therefore gaining market share is deterred by unproven credibility of the performance of the product. The flow of information between users and producers is limited. The flow of information on users environment through mass market to producers is essential for improving credibility of a product. The nature of knowledge base is tacit and the means of knowledge transmission is limited. Technological licensing and reverse engineering, Which have been conventional industry. These characteristics provide conditions of vicious circle in accumulation of technological capability of the numerical controller industry. This paper argues that these characteristics of the industry challenges existing approach to R&D management and framework of science and technology policy.

• International Journal of Advanced Culture Technology
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• v.5 no.3
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• pp.56-66
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• 2017

E-Government is an administrative innovation that utilizes information technology and is the most powerful means to strengthen government competitiveness. At this moment, countries around the world are continuously improving government competitiveness by continuously implementing government innovation through the implementation of e-Government. Many scholars argue that e-Government should be changed in response to the Fourth Industrial Revolution. Therefore, Korea adopted the government 3.0 instead of the e-Government and promoted the information policy. But the result was a failure. Korea was once a leading country in e-Government, but now it is falling due to government 3.0. The reason can be analyzed in various ways. First of all, over the past decade, Korea's e-Government has been neglected without obtaining the permanence of policy. And the Korea government pursued a new strategy under the name of disconnecting from the past and lost policy permanence. Therefore, future information policy, especially e-Government policies, should be pursued from a politically neutral point of view. The lesson of government 3.0 failure in Korea is clear. Regardless of the government's replacement & regime change, the information policy should be pursued with consistency.

• Journal of Families and Better Life
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• v.22 no.3
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• pp.35-46
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• 2004

The purpose of this study was to examine the residents' opinions on the degree of importance, and satisfaction with, the managerial service of multi-family housing. Residents' participation in managerial activities was also examined, because residents' opinions should be taken into serious consideration in order to improve the efficiency of housing management. Research methods used in this study were survey, field study, and content analysis of professionals' opinions. Survey data of 520 residents who live in multi-family housing were analyzed by means, frequencies, correlation, chi-square tests, t-tests, one-way ANOVA, post-hoc estimation (Scheffee test), and regression. The major findings of this study were as follows: First, many residents were dissatisfied with the quality of managerial service, but they thought that managerial services were very important. For example, they thought that safety inspection of the playground was very important, yet the current level of service was not satisfactory. Second, the characteristics of residents that determined the degree of residential satisfaction were income the location of the residence, and degree of participation in the community events. Third, the residents generally did not want to participate in the managerial services and community programs through such activities as participation in resident committee. In order to improve the housing management efficiency, residents' participation is critical. Some participants in this study pointed out that the details of management service and future plans need to be made public. New management models need to be developed to promote residents' participation and increase their satisfaction in the management.

• Progress in Superconductivity and Cryogenics
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• v.4 no.1
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• pp.78-83
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• 2002

Since the KSTAR superconducting magnet structure should be maintained at a cryogenic temperature of about 4 K, even a small amount of heat might be a major cause of the temperature rise of the structure. The Joule heating by eddy currents induced in the magnet structure during the KSTAR operation was found to be a critical parameter for designing the cooling scheme of the magnet structure as well as defining the requirements of the refrigerator for the cryogenic system. Based on the Joule heating calculation, it was revealed that the bulk temperature rise of the magnet coil structure was less than 1 K. The local maximum temperature especially at the inboard leg of the TF coil structure increased as high as about 21 K for the plasma vertical disruption scenario. For the CS coil structure, the maximum temperature was obtained from the PF fast discharging scenario. This means that the vertical disruption and PF fast discharging scenarios are the major scenarios for the design of TF and CS coil structures, respectively. For the reference scenario, the location of maximum temperature spot changes according to the transient current variation of each PF coil.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.1
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• pp.126-131
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• 2009

This study was carried out for the reliability of PD(Partial Discharge) pattern recognition. For the pattern recognition, the database for PD was established by use of self-designed insulation defects which occur and were mostly critical in GIS(Gas Insulated Switchgear). The acquired database was analyzed to distinguish patterns by means of PRPD(Phase Resolved Partial Discharge) method and stored to the form with to unite the average amplitude of PD pulse and the number of PD pulse as the input data of neural network. In order to prove the performance of genetic algorithm combined with neural network, the neural networks with trial-and-error method and the neural network with genetic algorithm were trained by same training data and compared to the results of their pattern recognition rate. As a result, the recognition success rate of defects was 93.2% and the neural network train process by use of trial-and-error method was very time consuming. The recognition success rate of defects, on the other hand, was 100% by applying the genetic algorithm at neural network and it took a relatively short time to find the best solution of parameters for optimization. Especially, it could be possible that the scrupulous parameters were obtained by genetic algorithm.

• Fibers and Polymers
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• v.4 no.4
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• pp.188-194
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• 2003

Phase behavior and spinodal phase separation kinetics in binary blends of a random copolymer of vinylidene fluoride and trifluoroethylene (75/25) [P(VDF/TrFE)] and poly(l,4-butylene adipate) (PBA) have been investigated by means of optical microscopic observation and time-resolved light scattering. The blends exhibited a typical lower critical solution temperature (LCST)∼${34}^{\circ}C$ above the melting temperature of the P(VDF/TrFE) crystals over the entire blend composition range. P(VDF/TrFE) and PBA were totally miscible in the temperature gap between the melting point of P(VDF/TrFE) and the LCST. Temperature jump experiments of the 3/7 P(VDF/TrFE)/PBA blend were carried out on a light-scattering apparatus from a single-phase melt state (${180}^{\circ}C$) to a two-phase region (205∼${215}^{\circ}C$). Since the late stage of spinodal decomposition (SD) is prevalent in the 3/7 blend, SD was analyzed using a power law scheme. Self-similarity was preserved well in the late stage of SD in the 3/7 blend.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2000.11a
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• pp.17-20
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• 2000

Structural genomics aims to provide a good experimental structure or computational model of every tractable protein in a complete genome. Underlying this goal is the immense value of protein structure, especially in permitting recognition of distant evolutionary relationships for proteins whose sequence analysis has failed to find any significant homolog. A considerable fraction of the genes in all sequenced genomes have no known function, and structure determination provides a direct means of revealing homology that may be used to infer their putative molecular function. The solved structures will be similarly useful for elucidating the biochemical or biophysical role of proteins that have been previously ascribed only phenotypic functions. More generally, knowledge of an increasingly complete repertoire of protein structures will aid structure prediction methods, improve understanding of protein structure, and ultimately lend insight into molecular interactions and pathways. We use computational methods to select families whose structures cannot be predicted and which are likely to be amenable to experimental characterization. Methods to be employed included modern sequence analysis and clustering algorithms. A critical component is consultation of the presage database for structural genomics, which records the community's experimental work underway and computational predictions. The protein families are ranked according to several criteria including taxonomic diversity and known functional information. Individual proteins, often homologs from hyperthermophiles, are selected from these families as targets for structure determination. The solved structures are examined for structural similarity to other proteins of known structure. Homologous proteins in sequence databases are computationally modeled, to provide a resource of protein structure models complementing the experimentally solved protein structures.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.4
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• pp.41-50
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• 2020

The paper aims to investigate auditors, auditing firms and other external factors that affect quality of information technology audit in Vietnam. We conducted 2 types of data collections including direct and on survey. For direct survey, we sent directly to auditors at the training classes organized by State Securities Exchanges Commission. An online survey was established and Google doc link was provided to the Big4 and non-Big4 auditors. We received 138 survey responses in that 90 auditors came from Big4 and 48 auditors from non-Big4 firms. The data are analyzed using a factor analysis and compare means approaches to illustrate the potential IT audit quality factors and identify differences between two groups of auditors. The results show that independence and accounting knowledge and audit skills are the most important factors. And since external auditors perform many assurance services, the independence is critical. The result also shows that the auditors need to have enough competent and professional skills when conducting an audit, especially within an IT environment that requires high quality. The findings suggest a similar pattern of two groups in the context of Vietnam and some factors of auditors and auditing firms appear to have a statistically significant impact on quality of IT audit.