• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 춘계학술대회 논문집
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• pp.164-167
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• 2006

Micro lens especially for optical pick up(Blu-ray) lens module is one of the key products for IT technology. Specific attention has been given to manufacturing of large radius lens but little to small radius less than 2mm diameter with N.A>0.8. This paper deals with a high precision glass molding technology for mass production of Blu-ray pick up lens. Ultra precisely machined tungsten carbide core and glass molding equipments are utilized for forming process. Evaluation was performed in terms of profile accuracy, surface roughness and thickness of fabricated glass lens.

• Structural Engineering and Mechanics
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• 제48권2호
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• pp.173-193
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• 2013

In this paper, influence of geometric configurations of multi-story bracing on shear lag behaviour of braced tube structures is investigated. The shear lag of 24-, 36- and 72-story braced tube structures are assessed considering all possible configurations of overall X and Chevron bracing types. Based on the analytical results, empirical equations, useful for the preliminary design phase, are proposed to provide the optimum number of stories that braced, in order to exert minimum shear lag on structures. Studying the interaction behaviour of a tube and different bracing types along with paying attention to the shear lag behaviour, a better explanation about the reasons behind the efficiency of a specific bracing module in decreasing the shear lag is developed. The analytical results show that there are distinct differences between the anatomy of braced tube structures with X and Chevron bracing regarding the shear lag behaviour.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권1호
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• pp.436-453
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• 2018

Storage cloud scheme, pushing data to the storage cloud poses much attention regarding data confidentiality. With encryption concept, data accessibility is limited because of encrypted data. To secure storage system with high access power is complicated due to dispersed storage environment. In this paper, we propose a hardware-based security scheme such that a secure dispersed storage system using erasure code is articulated. We designed a hardware-based security scheme with data encoding operations and migration capabilities. Using TPM (Trusted Platform Module), the data integrity and security is evaluated and achieved.

• 말소리와 음성과학
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• 제9권3호
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• pp.49-56
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• 2017

Much research attention has been directed to identify how native speakers perceive non-native speakers' oral proficiency. To investigate the generalizability of previous findings, this study examined segmental, phonological, accentual, and temporal correlates of native speakers' evaluation of L2 Korean proficiency produced by learners with various levels and nationalities. Our experiment results show that proficiency ratings by native speakers significantly correlate not only with rate of speech, but also with the segmental accuracies. The influence of segmental errors has the highest correlation with the proficiency of L2 Korean speech. We further verified this finding within substitution, deletion, insertion error rates. Although phonological accuracy was expected to be highly correlated with the proficiency score, it was the least influential measure. Another new finding in this study is that the role of pitch and accent has been underemphasized so far in the non-native Korean speech perception studies. This work will serve as the groundwork for the development of automatic assessment module in Korean CAPT system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.454-456
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• 2002

Embedded system is used a lot in electric home appliances and home network equipment. However, this system is designed to operate by the system operator directly at home and operator could find out them only when he pays attention to the system in case event happens. In this paper, to improve above things, it designed to remote-control system anywhere in which internet access is possible as well as at home, and also it designed SMS(short message service) information transmission system to inform the errors to the operator when they happen. To design the system, development board(be included the Strong Arm), CDMA module, and electric door lock are used as hardware, and web browser, CGI(common gateway interface) programming, and C-language are used for implementation of software in embedded-linux platform.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2000년도 제1회 학술대회 논문집
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• pp.77-78
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• 2000

We verified the charged static electricity on LCD glass influences upon the etching uniformity of dry etching process by plasma. In the TFT-LCD manufacturing process, we mainly paid attention to eliminate the static electricity for TFT reliability. The static electricity caused the serious ununiformity of etching surface profile and etching rate in the dry etch process. Through our experiment on the made static electricity from -200V to -1000V, it was confirmed that the static electricity on LCD glass caused the etching rate variation of $1.5%{\sim}15%$. We recommend the etching process equipment for LCD manufacturing have to establish the soft X-ray exposure module system for eliminating the static electricity inside the loading and unloading chamber.

• 한국태양에너지학회 논문집
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• 제28권3호
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• pp.21-26
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• 2008

Solar cells are renewable energy source which is not only environmentally friendly but also economically viable. For that matter, thin film materials are in observed with great in terest by a number of sources throughout the nations. Among these, CdTe (Cadium telluride) and CIS (copper indium diselenide) are the latest commercial products that are gathering attention in the solar cells markets. However there are some downsides to this newly invention. Since the materials are embedded, in the occasion of damage, certain amount of module residue can be released to water or soil. This paper outlines the results of our outdoor leaching experiments on photovoltaic (PV) samples broken into small fragments and been observed for 1 year.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.51-52
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• 2012

Among the PV-AC module topologies, the flyback inverter have been occupied the attention due to its simplicities on configuration and control. Proposed switching control method changes the mode of operation in DCM and BCM alternatively. It is expected that the high performances in efficiency and extension of input voltage range can be achieved by the conduction mode change. Proposed switching technique is validated by PSIM simulation.

• 대한수학회보
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• 제58권2호
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• pp.461-479
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• 2021

This paper includes a general version of Bessel multipliers in Hilbert C∗-modules. In fact, by combining analysis, an operator on the standard Hilbert C∗-module and synthesis, we reach so-called generalized Bessel multipliers. Because of their importance for applications, we are interested to determine cases when generalized multipliers are invertible. We investigate some necessary or sufficient conditions for the invertibility of such operators and also we look at which perturbation of parameters preserve the invertibility of them. Subsequently, our attention is on how to express the inverse of an invertible generalized frame multiplier as a multiplier. In fact, we show that for all frames, the inverse of any invertible frame multiplier with an invertible symbol can always be represented as a multiplier with an invertible symbol and appropriate dual frames of the given ones.

• 한국정보전자통신기술학회논문지
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• 제14권4호
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• pp.314-322
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• 2021

Skeleton-based action recognition has attracted considerable attention in human action recognition. Recent methods for skeleton-based action recognition employ spatiotemporal graph convolutional networks (GCNs) and have remarkable performance. However, most of them have heavy computational complexity for robust action recognition. To solve this problem, we propose a shuffle graph convolutional network (SGCN) which is a lightweight graph convolutional network using pointwise group convolution rather than pointwise convolution to reduce computational cost. Our SGCN is composed of spatial and temporal GCN. The spatial shuffle GCN contains pointwise group convolution and part shuffle module which enhances local and global information between correlated joints. In addition, the temporal shuffle GCN contains depthwise convolution to maintain a large receptive field. Our model achieves comparable performance with lowest computational cost and exceeds the performance of baseline at 0.3% and 1.2% on NTU RGB+D and NTU RGB+D 120 datasets, respectively.