• Nuclear industry
• /
• no.5_6 s.21
• /
• pp.44-50
• /
• 1980

• Nuclear industry
• /
• no.7_8 s.22
• /
• pp.20-28
• /
• 1980

• Journal of the Korean Society for Precision Engineering
• /
• v.29 no.12
• /
• pp.1376-1381
• /
• 2012

Optical devices are used extensively in the field of information network. Increasing demand for optical device, optical interconnection has been a important issue for commercialization. However many problems exist in the interconnection between optical device and optical fiber, and in the case of the multi-channel, problems of the optical alignment and optical array arise. For solving the alignment and array problem of optical device and the optical fiber, we fabricated fiber alignment and array by using imprint technology. Achieved higher precision of optical fiber alignment and array due to fabricating using imprint technology. The silicon stamp with different depth was fabricated using the conventional photolithography. Using the silicon stamp, a nickel stamp was fabricated by electroforming process. We conducted imprint process using the nickel stamp with different depth. The optical alignment and array by fabricating the patterns of optical device and fiber alignment and array using imprint process, and achieved higher precision of decreasing the dimensional error of the patterns by optimization of process. The fabricated optical interconnection of PLC device was measured 3.9 dB and 4.2 dB, lower than criteria specified by international standard.

• Korean Journal of Optics and Photonics
• /
• v.17 no.4
• /
• pp.317-322
• /
• 2006

A polymeric arrayed waveguide grating (AWG) has been proposed and demonstrated by exploiting the nanoimprint method. A PDMS(polydimethylsiloxane) stamp with device patterns engraved was developed out of a master mold made of quartz glass. The device was fabricated by transferring the pattern in the PDMS stamp to a spin-coated polymer film without using any etching process. The device had 8 output channels, while the center wavelengths of each output channel were positioned from 1543.7 nm to 1548.3 nm with the spacing of 0.8 nm. The achieved average channel crosstalk and the 3-dB bandwidth were about 10 dB and 0.8 nm respectively.

• Journal of Internet Computing and Services
• /
• v.7 no.4
• /
• pp.79-90
• /
• 2006

Data broadcasting is an efficient method for disseminating data, and is widely accepted in the database applications of mobile computing environments because of its asymmetric communication bandwidth between a server and mobile clients. This requires new types of concurrency control mechanism to support mobile transactions executed in the mobile clients, which have low-bandwidths toward the server. In this paper, we propose an OCC/DTA (Optimistic Concurrency Control with Dynamic Time-stamp Adjustment) protocol that can be efficiently adapted to mobile computing environments. The protocol reduces communication overhead by using client-side validation procedure and enhances transaction throughput by adjusting serialization order without violating transaction semantics. We show that the proposed protocol satisfies data consistency requirements, and simulate that this protocol can improve the performance of mobile transactions in data broadcasting environments.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.35 no.9
• /
• pp.1015-1020
• /
• 2011

Nanoimprint lithography has been actively investigated. This method can replicate a nanopatterned master stamp onto a thin polymer film on a silicon substrate and so on. In this study, a square-shaped hollow piezoelectric actuator is presented, which is newly developed. This actuator is used for driving a nanoscale stamp in nanoimprint lithography instead of a conventional electric motor. The fabricated prototype actuator has 95 layers and side lengths of 23 mm and 18 mm for the outer and inner squares, respectively. By adopting a novel process instead of the conventional forming process for fabricating a one-layer actuator, the one-layer is composed of four rectangular segments produced by sawing a ceramic film with a thickness of 0.3 mm. The basic characteristics on displacement and generation force of the fabricated prototype actuator are experimentally investigated. Furthermore, the displacement characteristics obtained by using a PI controller are tested and discussed.

• Nutrition Research and Practice
• /
• v.13 no.5
• /
• pp.410-414
• /
• 2019

BACKGROUND/OBJECTIVES: Several nutritional screening tools were recently developed to screen the risk of malnutrition in hospitalized children, but have not been validated in Asia. We compared four nutritional screening tools for pediatric patients in evaluating nutritional risks in newly hospitalized children. SUBJECTS/METHODS: Medical records of newly admitted pediatric patients between June 2016 and May 2017 at two tertiary hospitals were reviewed. Initial information by nurses and hospital records by doctors on baseline demographic, clinical, and anthropometric data at admission were collected in all subjects. Nutritional risks were evaluated using four nutritional screening tools including the pediatric nutritional risk score (PNRS), the screening tool for the assessment of malnutrition in pediatrics (STAMP), the paediatric Yorkhill malnutrition score (PYMS), and the screening tools for risk of nutritional status and growth (STRONGkids). RESULTS: A total of 559 patients (310 boys and 249 girls, mean age $6.3{\pm}5.5years$) were recruited. Patients in medical and surgical departments were 469 (83.9%) and 90 (16.1%), respectively. The prevalence of patients at risk of malnutrition were 31.1% for low risk, 52.2% for medium risk, and 16.6% for high risk by PNRS; 11.4%, 39.7%, and 48.8% by STAMP; 26.5%, 25.4%, and 48.1% by PYMS; and 35.6%, 58.9%, and 5.5% by STRONGkids. PNRS versus STRONGkids and STAMP versus PYMS showed moderate agreement (kappa = 0.566 and kappa = 0.495, respectively). PYMS and STAMP revealed a relatively high sensitivity of 87.8% and 77.6% for wasting. CONCLUSION: Different nutritional screening tools revealed considerably different results in evaluating nutritional risks in newly hospitalized children. Since pediatric patients are at risk of malnutrition at admission and during hospitalization, screening tools should be applied properly according to the situation of each hospital.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.19 no.2
• /
• pp.93-103
• /
• 2009

In this paper, we propose a USIM-based Authentication Scheme for 3GPP Network Access. The proposed scheme improves the problems of existing authentication protocol in 3GPP Network such as sequence number synchronization problem, the storage overhead of authentication data, and bandwidth consumption between Serving Network and Home Network. Our proposal is based on the USIM-based Authentication and Key Agreement Protocol that is defined in 3GPP Specification. In our scheme, mobile nodes share a SK with Serving Network and use a time stamp when mobile nodes are performing an authentication procedure with Serving Network. By using time stamp, there is no reason for using sequence number to match the authentication vector between mobile nodes and networks. So, synchronization problem can be solved in our scheme. As well as our scheme uses an authentication vector, the storage overhead of authentication data in Serving Network and bandwidth consumption between networks can be improved.

• The Journal of Internal Korean Medicine
• /
• v.43 no.6
• /
• pp.1134-1148
• /
• 2022

Purpose: We evaluated whether Spatholobus suberectus extract (SSE) can be used as a means of preventing and treating osteoporosis by measuring its effect on osteoclast differentiation, gene expression, and bone resorption. Methods: SSE was used to examine the effect on RAW 264.7 cells stimulated with RANKL to induce bone resorption. The inhibitory effect of TRAP formation and the expression of the bone resorption factors TRAP, cathepsin K, and MMP-9 during differentiation were measured. The effects on the differentiation-related factors NFATc and TRAIL and on the expression of OC-STAMP, DC-STAMP, ATP6v0d2, MITF, c-Fos, and inflammation-related factors were also evaluated. The effect on bone resorption was evaluated by culturing RANKL-treated osteoclasts on artificial bone fragments and observing the resulting resorption traces. The effect on bone damage in experimental animals was also measured. Results: SSE inhibited the differentiation of RANKL-stimulated osteoclasts into osteoclasts and suppressed the expression of cathepsin K, TRAP, MMP-9, NFATc1, TRAIL, MITF, OC-STAMP, DC-STAMP, ATP6v0d2, and c-Fos genes. Bone pore formation due to osteoclast action was also inhibited, and LPS-induced bone loss was suppressed in animal experiments. Conclusions: SSE could be useful for the prevention or treatment of osteoporosis by inhibiting osteoclast differentiation and bone resorption and suppressing bone loss induced in experimental animals. However, studies of larger populations are required.

• Composites Research
• /
• v.36 no.5
• /
• pp.321-328
• /
• 2023

This study developed the in-situ stamp-forming process using the multi-axis robotic arm to fabricate thermal composite parts. Optimal fabrication parameters with the multi-axis robotic arm were determined using finite element analysis and these parameters were further refined through the practical manufacturing process. A comparison between the manufactured parts and finite element analysis results was conducted regarding thickness uniformity and wrinkle distribution to confirm the validity of the finite element analysis. Additionally, to evaluate the formability of the manufactured composite parts, measurements of crystallinity and porosity were taken. Consequently, this study establishes the feasibility of the In-situ stamp-forming consolidation using a robotic arm and verifies the potential for producing composite parts through this process.