• Journal of KIISE:Computer Systems and Theory
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• v.26 no.8
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• pp.905-917
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• 1999

멀티미디어 시스템에서 수행되는 부하 중 상당 부분은 정해진 시간에 주기적으로 수행되어 연속 매체(continuous media)를 처리하는 주기 태스크들이다. 연속 매체들을 처리하는 두 주기 태스크의 수행 요청 시간(release time)간에 인공적인 위상(phase)을 줄 경우, 전체 부하의 처리 타이밍에 영향을 주게 되며, 특히, 적절한 위상을 부여할 경우 부하가 고르게 분산된다. 부하의 고른 분산은 태스크 간섭을 줄여 지터(jitter), 종료시한 초과(deadline miss), 그리고 긴 응답 시간(response time) 등의 문제를 해소시킨다. 본 논문에서는 새로운 위상 스케줄링(phased scheduling) 알고리즘 및 알고리즘을 개발하고 평가할 수 있는 실험 환경을 제안한다. 본 논문에 제시된 알고리즘은 저자들의 선행 논문 1 에서 제시한 알고리즘의 대안이다. 새로운 알고리즘은 정확하게 최적의 위상을 찾지는 않으나 기존 알고리즘보다 빠르게 수행되며 적용 범위가 넓다.Abstract A multimedia system consists of substantial amount of continuous media workload scheduled periodically at deterministic time points. Artificial phase between the invocation times of any two continuous media tasks affects the timing of the entire workload. A proper phase configuration distributes workload uniformly over time and reduces task interference that may otherwise result in jitter, deadline miss, and long response time. The objective of this paper is to work out a phased scheduling algorithm and to evaluate its effectiveness. The algorithm in this paper is an alternative approach to our previous work 1 . It is almost as accurate as the predecessor but two of three times faster in identifying the appropriate phase vector.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.4
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• pp.705-713
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• 2004

The objectives of this study were to evaluate the fluoride release and the change of surface roughness of fluoride releasing restorative materials after toothbrush-dentifrice abrasion. Seven commercially available fluoride releasing restorative materials (Fuji II LC Improved: FL, Compoglass F: CG, Dyract AP: DR, F2000: FT, Ariston: AT, Tetric: TR, and Gradia: GD) were selected as experimental materials. The results obtained were summarized as follows: 1. The AT, FL, and CF groups produce an initially large burst of fluoride release and comparatively low but continuous release of fluoride. But other groups produce no initial burst of fluoride and levels of release remain relatively constant. 2. The rate of fluoride release remains steady state after 40 days. The results of Tukey's test (P<.05), the fluoride release showed the order of decreasing rank as follows: AT > FL > compomers > TC and GD. 3. The surface roughness indicated that the highest value was observed in the FT group and the lowest value was observed in the CF group. The surface roughness of Tukey's test showed the significant differences between groups of FT, AT and FL and groups of CF, DR, GD and TC (P<0.05).

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.3
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• pp.287-291
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• 2011

We solve the simple physical model for liquid pool spreading with vaporization semi-analytically for the first time, using perturbation techniques. The results are compared with those obtained using numerical methods. We use the evaporation rate per unit area as a perturbation parameter, and first-order solutions are obtained for continuous and instantaneous release. The two solutions are nearly identical with respect to the pool radius. The pool volumes are nearly the same at the early stage of the spread and then start to diverge.

• Asian-Australasian Journal of Animal Sciences
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• v.3 no.1
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• pp.53-59
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• 1990

A study was conducted to investigate the release pattern of zinc form the zinc containing boluses and to see whether the released zinc can cure a zinc deficiency in sheep. Three sheep were used in this experiment and were fed a low zinc semi-synthetic diet throughout the experimental period. Each sheep was given a single pre-weighed zinc containing bolus when blood variables showed continuous zinc deficiency. The zinc containing boluses when placed within the reticulo-rumen of zinc deficient sheep, release zinc at the rate of 106.6 mg zinc/day for 39 days. At the end of depletion period there was a reduced feed consumption, plasma zinc concentration, plasma alkaline phosphatase activity and increased plasma zinc binding capacity which were 409 g, 0.18 mg/l, 87 U/l and 88.7% respectively and 521 g, 0.18 mg/l, 142 U/l, and 89.5% respectively before first and second blousing. After the administration of the first and second boluses, the feed consumption, plasma zinc levels and plasma alkaline phosphatase activities rose rapidly and far exceeded the starting values. The zinc binding capacity was reduced to 21.9% due to the administration of the first and second boluses. It is concluded that zinc boluses can be used for curing a zinc deficiency in sheep.

• Coupled systems mechanics
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• v.8 no.1
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• pp.1-17
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• 2019

The present paper deals with delamination fracture analyses of the multilayered functionally graded non-linear elastic Symmetric Split Beam (SSB) configurations. The material is functionally graded in both width and height directions in each layer. It is assumed that the material properties are distributed non-symmetrically with respect to the centroidal axes of the beam cross-section. Sine laws are used to describe the continuous variation of the material properties in the cross-sections of the layers. The delamination fracture is analyzed in terms of the strain energy release rate by considering the balance of the energy. A comparison with the J-integral is performed for verification. The solution derived is used for parametric analyses of the delamination fracture behavior of the multilayered functionally graded SSB in order to evaluate the effects of the sine gradients of the three material properties in the width and height directions of the layers and the location of the crack along the beam width on the strain energy release rate. The solution obtained is valid for two-dimensional functionally graded non-linear elastic SSB configurations which are made of an arbitrary number of lengthwise vertical layers. A delamination crack is located arbitrary between layers. Thus, the two crack arms have different widths. Besides, the layers have individual widths and material properties.

• Geosystem Engineering
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• v.21 no.5
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• pp.282-290
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• 2018

The onset of extreme fire behaviour in a mine drift with longitudinal ventilation was analysed. A fire in a mine drift with continuous fuel load, involving several separate fires may lead to flames tilted horizontally and filling up the entire cross section. This will lead to earlier ignition, higher fire growth rate, higher fire spread rate and a severe fire behaviour. The focus has been on what changes take place at the onset and signs of the impending phenomenon. It was found that the fire gas temperature at the ceiling level provided a poor indicator. At the downstream far-field region of the fire, the sudden temperature increase at the lowest levels of the cross section and the sudden increase in flow velocities would provide signs of extreme fire behaviour. The corresponding full-scale heat release rates of the experiments at the onset of extreme fire behaviour were found to be very high for mining applications but not necessarily for tunnel fires. The heat release rate threshold for a mine drift with smaller cross-sectional dimensions would decrease considerably, increasing the likelihood of occurrence. The distance between the fuel items will play an important role during the initiation of horizontal flames.

• Coupled systems mechanics
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• v.12 no.4
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• pp.297-313
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• 2023

This paper deals with delamination analysis of non-linear viscoelastic multilayered beam subjected to bending in the plane of the layers. For this purpose, first, a non-linear viscoelastic model is presented. In order to take into account the non-linear viscoelastic behaviour, a non-linear spring and a non-linear dashpot are assembled in series with a linear spring connected in parallel to a linear dashpot. The behaviours of the non-linear spring and dashpot are described by applying non-linear stress-strain and stress-rate of strain relationships, respectively. The constitutive law of the model is derived. Due to the non-linear spring and dashpot, the constitutive law is non-linear. This law is used for describing the time-dependent mechanical behaviour of the beam under consideration. The material properties involved in the constitutive law vary along the beam length due to the continuous material inhomogeneity of the layers. Solution of the strain energy release rate for the delamination is obtained by analyzing the balance of the energy with considering of the non-linear viscoelastic behaviour. The strain energy release rate is found also by using the complementary strain energy for verification. A parametric study is carried-out by using the solution obtained. The solutions derived and the results obtained help to understand the time-dependent delamination of non-linear viscoelastic beams under loading in the plane of layers.

• The Journal of Korea Robotics Society
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• v.19 no.1
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• pp.53-57
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• 2024

A hopping robot can move through a confined environment while overcoming obstacles. To create a small hopping robot, it must be able to generate a large amount of energy and release it at the same time. However, due to the small size of the robot, there is a limit to the size of the actuator that can be used, so it is mainly used to collect energy in an elastic element and release it at once. In this paper, we propose a small hopping robot with a simplified design by removing ancillary parts and enabling continuous hopping using only a small actuator based on a direct-drive method. In addition, repeated actuation over the rated voltage can cause thermal breakdown of the actuator. To check the safety of the actuator at high voltage, we perform modeling to predict the temperature of the actuator and verify the accuracy of the modeling through experiments.

• Nuclear Engineering and Technology
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• v.56 no.4
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• pp.1513-1525
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• 2024

An improved mitigation system for thermally-induced steam generator tube rupture accidents was introduced to prevent direct environmental release of fission products bypassing the containment in the OPR1000. This involves injecting bypassed steam into the containment, cooling, and decontaminating it using a water coolant tank. To evaluate its performance, a severe accident analysis was performed using the MELCOR 2.2 code for OPR1000. Simulation results show that the proposed system sufficiently prevented the release of radioactive nuclides (RNs) into the environment via containment injection. The pool scrubbing system effectively decontaminated the injected RN and consequently reduced the aerosol mass in the containment atmosphere. However, the decay heat of the collected RNs causes re-vaporization. To restrict the re-vaporization, an external water source was considered, where the decontamination performance was significantly improved, and the RNs were effectively isolated. However, due to the continuous evaporation of the feed water caused by decay heat, a substantial amount of steam is released into the containment. Despite the slight pressurization inside the containment by the injected and evaporated steam, the steam decreased the hydrogen mole fraction, thereby reducing the possibility of ignition.

• Korean Journal of Environmental Agriculture
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• v.42 no.4
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• pp.435-443
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• 2023

Global concern over climate change, driven by greenhouse gas emissions, has prompted widespread interest in sustainable solutions. In the agricultural sector, biochar has emerged as a focal point for mitigating these emissions. This study investigated the impact of continuous biochar application on CO₂ and N₂O emissions during the spring cabbage cultivation period. Greenhouse gas emissions in the biochar treatment groups (soils treated with 1, 3, and 5 tons/ha of rice husk biochar) were compared to those in the control group without biochar. During the spring cabbage cultivation period in 2022, the total CO₂ emissions were in the range of 71.6-119.0 g/m² day, and in 2023, with continuous biochar application, they were in the range of 71.6-102.1 g/m² day. The total emissions of N₂O in 2022 and 2023 were in the range of 11.7-23.7 and 7.8-19.9 g/m² day, respectively. Overall, greenhouse gas emissions decreased after biochar treatment, confirming the positive influence of biochar on mitigating greenhouse gas release from the soil. Nevertheless, further research over an extended period exceeding five years is deemed essential to delve into the specific mechanisms behind these observed changes and to assess the long-term sustainability of biochar's impact on greenhouse gas dynamics in agricultural settings.