• Journal of Electrical Engineering and information Science
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• v.1 no.1
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• pp.160-163
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• 1996

New formulas for McClellan transform parameters for the design of 2-D zero-phase FIR fan filters are optimally derived under the integral squared error(ISE) criterion. By imposing the constraint that F(0, 0)=\ulcorner, where F($.$) is the McClellan transform and $\omega$\ulcorner is the cutoff frequency of the 1-D prototype filter, the ISE is directly minimized without modifying it and, as a consequence, closed-form formulas for the McClellan transform parameters are obtained. It is shown that these formulas lead to a very efficient design for 2-D zero-phase FIR fan filters.

• The Journal of Korean Obstetrics and Gynecology
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• v.31 no.4
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• pp.1-15
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• 2018

Objectives: Osteoporosis is considered a serious human disease. We developed an extract of mixed herbs containing root of Platycodon grandiflorum (ExMH-PGR), which is expected to be effective in preventing or treating osteoporosis. The aim of this study was to investigate the anti-osteoporotic effect of ExMH-PGR in osteoblastic MC3T3-E1 cells and osteoclastic RAW 264.7 cells. Methods: To examine the anti-osteoporotic effect of ExMH-PGR, osteoblast and osteoclast differentiation were induced and cultured with various concentrations of ExMH-PGR. Alkaline phosphatase (ALP) activity, collagen synthesis, osteocalcin production, and mineralization in MC3T3-E1 cells were analyzed. Tartrate-resistant acid phosphatase (TRAP) activity and the formation of actin ring in RAW 264.7 cells were analyzed. Results: ExMH-PGR at concentration up to $25{\mu}g/mL$ significantly increased ALP activity, collagen synthesis, osteocalcin production, and mineralization in MC3T3-E1 cells. ExMH-PGR at 50 to $200{\mu}g/mL$ significantly inhibited TRAP activity and the formation of actin ring in RAW 264.7 cells. Conclusions: These results demonstrate that ExMH-PGR stimulates osteoblastic activities and inhibits osteoclastic activities in in vitro systems, suggesting that ExMH-PGR might be considered as an anti-osteoporotic candidate for treatment of osteoporosis disease.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.11
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• pp.1-7
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• 2004

We propose multistage parallel nulling (MPN) partial parallel interference cancellation (PPIC) receiver for downlink multiple-input multiple-output (MIMO) multicarrier (MC)-code division multiple access (CDMA) systems. Though the V-BLAST is a popular MIMO receiver, it shows error floor for multiuser downlink MIMO MC-CDMA systems. The proposed MPN-PPIC receiver does not produce error floor for multiuser case, and achieves substantial performance gains with multistage processing. For single user case, the proposed method also surpasses the V-BLAST receiver with multistage processing for MIMO MC-CDMA systems with chip level interleaving. The system performance of the proposed MPN-PPIC receiver is evaluated through computer simulations.

• Journal of Korea Water Resources Association
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• v.36 no.3 s.134
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• pp.365-374
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• 2003

This is a study on application of a TVD-Mccormack scheme for the computation of one-dimensional dam-break flows. The TVD scheme not only has the ability to damp out oscillations, but also does not contain terms with adjustable parameters. Moreover, the TVD-McCormack scheme does not cause any additional difficulty when dealing with the source term of the equation and retains second-order accuracy in both space and time. In this study, by appropriately designing the limiter functions, the TVD property can be achieved, and numerical oscillations near a jump discontinuities can be eliminated or reduced. Also, this numerical scheme has less computational errors when the direction of the predictor-corrector step is in the same direction as the shock wane propagation.

• Food Science of Animal Resources
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• v.20 no.3
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• pp.199-206
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• 2000

축육 생산시 주요 부산물인 돼지 심장근으로부터 항산화제(0.02% propyl gallate, 0.2% asxorbic acid, 0.2% sodium tripolyphosphate) 첨가 세척액(25 mM phosphate buffer, pH 6.0)에 의해 제조된 surimi(5% protein 0.6 M NaCl, 25 mM phosphate buffer, pH 6.0)를 alginate(0.4%), calcium carbonate(0.075%) 및 lactate(0.6%) 등의 첨가에 의해 AC surimi 로 조제한 다음, CMC 또는 MC를 일정수준 (0.5%, 1.0%) 첨가하여 surimi 의 pH, 겔의 보수력과 조리 손실을 비롯하여 겔읨 루성을 비교 검톻였다. CMC 첨가시 pH는 0.2 단위씩 감소하는 경향을 보인데 비해 MC 첨가시에는 뚜렷한 변화를 보이지는 않았다. 조리 손실에 대한 영향을 살펴 본 결과 CMC와 MC 첨가구에서 0.5% CMC 첨가구를 제외하고서는 나머지 세 처리구에서 감소하는 경향이었고, 특히 MC 첨가시에는 대조구에 비해 뚜렷한 감소 경향을 나타내었으나(p<0.05) 첨가수준에 따른 차이는 나타나지 않았다 CMC나 MC의 첨가는 보수력에 대해서는 거의 영향을 미치지 않은 것으로 나타났고, 물성에 대한 측정 결과에서 CMC 첨가시에는 겔의 강도. 경도 및 탄성등은 약간 증가하였으나 유의적인 차이를 나타내지는 않았고 (P<0.05), MC 첨가시에는 뚜렷한 차이를 나타내지 않았으며, 겔 응집성에 대해서는 CMC와 MC 첨가에 의해 서로 다른 경향을 나타내었다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.1A
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• pp.55-61
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• 2005

Mobile communication systems are required not only to support high-data-rate transmissions in favorable channel conditions but also to be able to tolerate hostile environments possibly encountered by cellular communications. This paper compares CDMA(Code Division Multiple Access), OFDM(Orthogonal Frequency Division Multiplexing), and MC-CDMA(Multi-Carrier CDMA)with inaccurate channel estimates and low SNR environments. The equations and simulation results show that the performance losses in CDMA systems due to imprecise channel estimates are not considerable while frequency-hopping of OFDM systems can result in more than l0dB SNR losses. Also, this paper show that frequency-spreading of MC-CDMA can be very helpful for channel compensation performances than frequency-hopping or time-spreading of OFDM.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.1A
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• pp.44-50
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• 2007

In typical MC-CDMA systems, different frequency-domain scrambling codes are randomly chosen from a given code set and then assigned to different subscriber stations using the same subcarrier set. When orthogonal codes are employed for the frequency-domain scrambling, the choice of the scrambling code does not affect the detection performance if the timing and frequency synchronizations are perfect and the channel characteristic is flat. However, in practical cases, inter-code interference often appears due to the broken code orthogonality. In this paper, the optimal order of allocating the orthogonal frequency-domain scrambling codes to new subscriber stations is derived under non-negligible timing offsets in MC-CDMA system.

• International Journal of Precision Engineering and Manufacturing-Green Technology
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• v.5 no.5
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• pp.605-612
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• 2018

This work investigates the relationships between the static mechanical properties of Ti-6Al-4V manufactured through selective laser melting (SLM) and post-process heat treatments, namely stress relieve, annealing and hot isostatic pressing (HIP). In particular, Ti-6Al-4V parts were fabricated in three different build orientations of X, Z, and $45^{\circ}$ to investigate the multi-directional mechanical properties. The results showed that fully densified Ti-6Al-4V parts with densities of up to 99.5% were obtained with optimized SLM parameters. The microstructure of stress relieved and mill annealed samples was dominated by fine ${\alpha}^{\prime}$ martensitic needles. After HIP treatment, the martensite structure was fully transformed into ${\alpha}$ and ${\beta}$ phases (${\alpha}+{\beta}$ lamellar). Within the realm of tensile properties, the yield and ultimate strength values were found statistically similar with respect to the built orientation for a given heat treatment. However, the ductility was found orientation dependent for the HIP samples, where a lower value was observed for samples built in the X direction.

• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3388-3400
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• 2023

Detailed analysis of the neutron pathway through matter inside the nuclear reactor core is exceedingly needed for safety and economic considerations. Due to the constant development of high-performance computing technologies, neutronics analysis using computer codes became more effective and efficient to perform sophisticated neutronics calculations. In this work, a commercial pressurized water reactor (PWR) presented by Virtual Environment for Reactor Applications (VERA) Core Physics Benchmark are modeled and simulated using a high-fidelity simulation of OpenMC code in terms of criticality and fuel pin power distribution. Various problems have been selected from VERA benchmark ranging from a simple two-dimension (2D) pin cell problem to a complex three dimension (3D) full core problem. The development of the code capabilities for reactor physics methods has been implemented to investigate the accuracy and performance of the OpenMC code against VERA SCALE codes. The results of OpenMC code exhibit excellent agreement with VERA results with maximum Root Mean Square Error (RMSE) values of less than 0.04% and 1.3% for the criticality eigenvalues and pin power distributions, respectively. This demonstrates the successful utilization of the OpenMC code as a simulation tool for a whole core analysis. Further works are undergoing on the accuracy of OpenMC simulations for the impact of different fuel types and burnup levels and the analysis of the transient behavior and coupled thermal hydraulic feedback.

• Journal of The Korean Radiological Technologist Association
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• v.25 no.1
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• pp.23-23
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• 1999

We tested MC in barium suspension for the evaluation of the gastrointestinal tract on CT examination. A total of 30 subjects who underwent CT with use of 900 ml of MC in barium suspention ($1.5\%$ weight/volume) were included for the study. Ant