• Journal of Biosystems Engineering
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• v.23 no.6
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• pp.583-590
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• 1998

This study was performed to determine the kinetic friction coefficient bulk density, dynamic and static angle of repose, and terminal velocity of the chopped rice straw in the moisture range of 8~23%, which could be used for better design and operation of the processing machinery and handling facilities. Friction coefficient was determined from the horizontal traction force measured by pulling the container holding the mass of rice straw on the various plate materials. Bulk density was measured with an apparatus consisting of a filling funnel and a receiving vessel. Dynamic angle of repose was calculated from the photos of bulk samples piled by gravity flow on a circular platform. Static angle of repose was determined by measuring the side angle of the bulk material which was left in the cylindrical container after natural discharge of the bulk sample through a circular hole in the bottom plate. Kinetic friction coefficients of rice straw on the PVC, mild steel, stainless steel, and galvanized steel were in the range of 0.303~0.434, 0.222~0.439, 0.204~0.448, and 0.206~0.407, respectively. and indicated linear increase with moisture content. The effects of moisture change on the friction coefficients were in the order of PVC, mild steel, galvanized steel, and stainless steel. Bulk density, dynamic and static angle of repose, and terminal velocity were in the range of 56.8~60.3 kg/m$^3$, 41.4~45.9$^{\circ}$, 94.4~100.8$^{\circ}$, and 1.07~4.48 m/s, respectively, and were increased linearly with the moisture content.

• Nuclear Engineering and Technology
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• v.32 no.1
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• pp.77-87
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• 2000

It is reported that the toughness and safety margins of the SA106 Gr.C main steam line piping steel is reduced due to dynamic strain aging (DSA) at the reactor operating temperature for Leak-Before-Break (LBB) application. In this study, intercritical annealing in two-phase ($\alpha$+${\gamma}$）region was performed to investigate the possibility of improving the toughness and reducing DSA susceptibility. The manifestations of DSA were still observed in the tensile tests of the annealed specimens. However, the ductility loss caused by DSA was smaller than that in the as-received material. Furthermore, the intercritical annealing was able to increase the Charpy impact toughness by 1.5 times compared to as-received. With the heat treatment, we could obtain microstructural changes such as the cleaner retained ferrite, increased ferrite content and somewhat finer grain size. It is considered that the reduced DSA was induced by cleaner retained ferrite, which in turn resulted in higher impact toughness in addition to the general toughening due to finer grain sizes and increased ferrite content.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.4
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• pp.1342-1359
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• 2021

The data deduplication technique identifies the duplicates and minimizes the redundant storage data in the backup server. The chunk level deduplication plays a significant role in detecting the appropriate chunk boundaries, which solves the challenges such as minimum throughput and maximum chunk size variance in the data stream. To provide the solution, we propose a new chunking algorithm called Dynamic Prime Chunking (DPC). The main goal of DPC is to dynamically change the window size within the prime value based on the minimum and maximum chunk size. According to the result, DPC provides high throughput and avoid significant chunk variance in the deduplication system. The implementation and experimental evaluation have been performed on the multimedia and operating system datasets. DPC has been compared with existing algorithms such as Rabin, TTTD, MAXP, and AE. Chunk Count, Chunking time, throughput, processing time, Bytes Saved per Second (BSPS) and Deduplication Elimination Ratio (DER) are the performance metrics analyzed in our work. Based on the analysis of the results, it is found that throughput and BSPS have improved. Firstly, DPC quantitatively improves throughput performance by more than 21% than AE. Secondly, BSPS increases a maximum of 11% than the existing AE algorithm. Due to the above reason, our algorithm minimizes the total processing time and achieves higher deduplication efficiency compared with the existing Content Defined Chunking (CDC) algorithms.

• Journal of IKEEE
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• v.27 no.1
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• pp.93-102
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• 2023

As one of the techniques for analyzing malicious code, techniques creating a sequence or a graph of function call relationships in an executable program and then analyzing the result are proposed. Such methods generally study function calling in the executable program code through static analysis and organize function call relationships into a sequence or a graph. However, in the case of an obfuscated executable program, it is difficult to analyze the function call relationship only with static analysis because the structure/content of the executable program file is different from the standard structure/content. In this paper, we propose a dynamic analysis method to analyze the function call relationship of an obfuscated execution program. We suggest constructing a function call relationship as a graph using the proposed technique.

• Geomechanics and Engineering
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• v.36 no.4
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• pp.317-328
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• 2024

Adopting a rational engineering methodology for building structures on sandy-clay soil layers has become increasingly important since it is crucial when structures erected on them often face seismic and cyclic wave loads. Such loads can cause a reduction in the stiffness, strength, and stability of the structure, particularly under un-drained conditions. Hence, this study aims to investigate how the dynamic properties of sand-clay mixtures are affected by loading frequency and clay content. Cyclic triaxial tests were performed on a total of 36 samples, comprising pure sand with a relative density of 60% and sand with varying percentages of clay. The tests were conducted under confining pressures of 50 and 100 kPa, and the samples' dynamic behavior was analyzed at loading frequencies of 0.1, 1, and 4 Hz. The findings indicate that an increase in confining pressure leads to greater inter-particle interaction and a reduced void ratio, which results in an increase in the soil's shear modulus. An increase in the shear strength and confinement of the samples led to a decrease in energy dissipation and damping ratio. Changes in loading frequency showed that as the frequency increased, the damping ratio decreased, and the strength of the samples increased. Increasing the loading frequency not only reflects changes in frequency but also reduces the relative permeability and enhances the resistance of samples. An analysis of the dynamic properties of sand and sand-clay mixtures indicates that the introduction of clay to a sand sample reduces the shear modulus and permeability properties.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.6
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• pp.128-135
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• 2003

This study is performed to examine the physical and mechanical properties of concrete using recycled aggregate and industrial by-products. The test results show that the unit weight, compressive and flexural strength, ultrasonic pulse velocity and dynamic modulus of elasticity are decreased with increasing the content of recycled aggregate. But, the absorption ratio is increased with increasing the content of recycled aggregate. The unit weight is 2,237∼2,307 kg/$\textrm{m}^3$, the absorption ratio is 2.96∼4.12%, the compressive strength is 415∼532 kgf/$\textrm{cm}^2$, the flexural strength is 75∼96 kgf/$\textrm{cm}^2$, the ultrasonic pulse velocity is 4,350∼4,949 m/s and the dynamic modulus of elasticity is $390\times10^3\;∼\;465\times10^3$ kg f/$\textrm{cm}^2$, respectively These recycled aggregate concrete can be used for high strength concrete.

• Journal of The Korean Society of Agricultural Engineers
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• v.51 no.1
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• pp.21-26
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• 2009

This study was performed to evaluate the physical and mechanical properties of concrete using waste activated carbon. Materials used were ordinary portlant cement, crushed coarse aggregate, natural fine aggregate, waste activated carbon, and superplasticizer. The substitution ratios of waste activated carbon were 0,1,2,3,4,5,6,7,8,9 and 10%. The unit weight was decreased and water absorption ratio was increased with increasing the waste activated carbon content, respectively. When the substitution ratio of waste activated carbon was 3%, compressive strength, flexural strength and dynamic modulus of elastisity were more higher than that of the ordinary portland cement (OPC), and it was decreased with increasing the waste activated carbon content, respectively. The most effective contents of waste activated carbon was 2% in performance and 4% in practical use Accordingly, waste activated carbon can be used for concrete material.

• Korea-Australia Rheology Journal
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• v.19 no.2
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• pp.81-88
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• 2007

Blends of collagen dispersion (COL) with poly(vinyl alcohol) (PVA) in different weight ratios were investigated by oscillatory rheometry, Fourier transform-infrared spectroscopy and scanning electron microscopy. It was found that even with 80% of PVA, the COL/PVA blends behaved more like collagen dispersion than pure PVA solution in the dynamic thermal and frequency processing, for instance, a dominant elastic appearance (G'>G"), a similar shear thinning behavior and the thermal denaturation below $40^{\circ}C$. However, influence on the blend behaviour by PVA was noticeable, for instance, an increase of dynamic denaturation temperature, the decreasing intensity of amide I, II and III bands as well as the diminishing irregular pores on the surface of blends. The interaction between collagen and PVA could be observed, especially at the regions with low content or high content of PVA.

• Structural Engineering and Mechanics
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• v.3 no.5
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• pp.497-509
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• 1995

Effectiveness of multiple tuned mass dampers (MTMD) in suppressing the dynamic response of base excited structure for first mode vibration is investigated. The effectiveness of the MTMD is expressed by the ratio of the root mean square (RMS) displacement of the structure with MTMD to corresponding displacement without MTMD. The frequency content of base excitation is modelled as a broad-band stationary random process. The MTMD's with uniformly distributed natural frequencies are considered for this purpose. A parametric study is conducted to investigate the fundamental characteristics of the MTMD's and the effect of important parameters on the effectiveness of the MTMD's. The parameters include: the fundamental characteristics of the MTMD system such as damping, mass ratio, total number of MTMD, tuning frequency ratio, frequency spacing of the dampers and frequency content of the base excitation. It has been shown that MTMD can be more effective and more robust than a single TMD with equal mass and damping ratio.

• The Transactions of the Korea Information Processing Society
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• v.6 no.7
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• pp.1955-1961
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• 1999

비디오 데이터는 비정형 데이터이고 정보의 양이 방대하기 때문에 내용기반 검색 방법이 필요하다. 비디오 데이터의 내용기반 검색을 위해서는 동영상 데이터의 색인이 필요한데, 일반적으로 비디오 색인을 하기 위한 시작점은 컷 검출이다. 본 논문에서는 컷 검출의 효율성을 향상시키기 위해서 컷 검출 과정 중 임계값이 동적으로 변화하는 동적 임계값 기법을 제안한다. 구현과 실험을 통하여 제안하는 방법이 기존의 방법보다 효율적임을 보였다. 6a A content-based search method is required for video which has an unformatted and huge size of data. The index technique is necessary for the content-based search of the video data. The first step of the video indexing is a cut detection. We propose a dynamic threshold method which changes a threshold value during the cut detection process. We demonstrate that the proposed method is more efficient than the existing methods.