• The KIPS Transactions:PartA
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• v.19A no.2
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• pp.77-84
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• 2012

Speculative execution for improving instruction-level parallelism is widely used in high-performance processors. In the speculative execution technique, the most important factor is the accuracy of branch predictor. Unfortunately, complex branch predictors for improving the accuracy can cause serious thermal problems in 3D multicore processors. Thermal problems have negative impact on the processor performance. This paper analyzes two methods to solve the thermal problems in the branch predictor of 3D multi-core processors. First method is dynamic thermal management which turns off the execution of the branch predictor when the temperature of the branch predictor exceeds the threshold. Second method is thermal-aware branch predictor placement policy by considering each layer's temperature in 3D multi-core processors. According to our evaluation, the branch predictor placement policy shows that average temperature is $87.69^{\circ}C$, and average maximum temperature gradient is $11.17^{\circ}C$. And, dynamic thermal management shows that average temperature is $89.64^{\circ}C$ and average maximum temperature gradient is $17.62^{\circ}C$. Proposed branch predictor placement policy has superior thermal efficiency than the dynamic thermal management. In the perspective of performance, the proposed branch predictor placement policy degrades the performance by 3.61%, while the dynamic thermal management degrades the performance by 27.66%.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.3
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• pp.924-942
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• 2020

The facial expression is diverse and various among persons due to the impact of the psychology factor. Whilst the facial action is comparatively steady because of the fixedness of the anatomic structure. Therefore, to improve performance of the action unit recognition will facilitate the facial expression recognition and provide profound basis for the mental state analysis, etc. However, it still a challenge job and recognition accuracy rate is limited, because the muscle movements around the face are tiny and the facial actions are not obvious accordingly. Taking account of the moving of muscles impact each other when person express their emotion, we propose to make full use of co-occurrence relationship among action units (AUs) in this paper. Considering the dynamic characteristic of AUs as well, we adopt the 3D Convolutional Neural Network(3DCNN) as base framework and proposed to recognize multiple action units around brows, nose and mouth specially contributing in the emotion expression with putting their co-occurrence relationships as constrain. The experiments have been conducted on a typical public dataset CASME and its variant CASME2 dataset. The experiment results show that our proposed AU co-occurrence constraint 3DCNN based AU recognition approach outperforms current approaches and demonstrate the effectiveness of taking use of AUs relationship in AU recognition.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.1
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• pp.110-122
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• 2020

Many companies make considerable efforts in implementing supply chain management systems to increase their competitiveness. In particular, there are significant investments in their ICT (Information and Communication Technology) and supply chain. However, considerable diversity exists in how well firms have been able to assimilate ICT and leverage the business value of it. In addition, studies on supply chains, particularly Real Time Enterprise (RTE) competence, which is cited for rapid information sharing and dynamic capabilities for each role in the supply chain, are insufficient. The purpose of this paper is to explore and evaluate effect of ICT utilization capabilities, including 'ICT internal cooperative capabilities' and 'ICT operational flexibility capabilities', on RTE capabilities (flexibility, visibility and prediction) and supply chain performance. To validate the research model proposed in the study, survey was conducted on companies using ICT along the supply chain of manufacturing industries. 216 data were used, SPSS and AMOS were used for the analysis methods. Study results showed that ICT internal collaboration capabilities affect agility, one of RTE capabilities, but not visibility and prediction, and ICT operational flexibility capabilities have affected all three RTE capacities. And, RTE capabilities had a huge impact on supply chain performance as expected. In this paper, it has been found that the ICT capabilities in manufacturing are an important factor in improving RTE capabilities that are important in the supply chain and improving the performance of the supply chain.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.4
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• pp.402-410
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• 2022

The present study introduces a calibration method of the CSC model implemented in the LS-DYNA program for considering the material properties of ultra-high performance concrete(UHPC). Based on previous experimental studies, various parameters, which constitute three shear failure surfaces, pressure-volumetric strain curve, fracture energy, dynamic increase factor(DIF), and so on, are modified. Then, the proposed calibration method is verified by comparing the numerical result with the experimental data through the single element analysis. In addition, based on the established finite element models, the applicability of the calibrated CSC model is examined for UHPC structures subjected to impact and blast loadings.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.2
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• pp.105-114
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• 2016

When impact load is applied to a plate structure, a common phenomenon that occurs in structures is plastic deformation accompanied by a large strain and eventually it will experience a fracture accordingly. In this study, for the rational design against accidental limit state, the plastic material constants of steel plate which is formed by line heating and by cold bending procedure have been defined through the numerical simulation for the high speed tension test. The usefulness of the material constants included in Cowper-Symonds model and Johnson-Cook model with the assumption that strain rate can be neglected when strain rate is less than the intermediate speed is verified through comparing the present numerical results with those in references. This paper ends with describing the future study.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.5
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• pp.35-40
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• 2010

The present study proposes the strengthening method to use Conclinic Advanced FiberWrep(CAF) so as to improve Load Carrying Capacity of the RC slab bridge. In order to evaluate the strengthening performance, we strengthen 50cm per unit-width of CAF to the slab's bottom of the test bridge that designed with DB 18, then perform Static and Dynamic Field Load Test. As a result of this, 14.7% of the maximum displacement, 5.0% of the strain and 33.7% of the impact factor are reduced after strengthening. At the middle of the test spans, nominal resisting ratio is increased by 27% and Service Load Carrying Capacity is increased by 44.6%, 48.9% of each span 1 and 2. In conclusion, this study indicates that the strengthening method using CAF is very effective to improve the deteriorated RC slab bridge designed with DB 18, to the DB 24 of the first class bridge design load.

• Journal of Powder Materials
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• v.29 no.2
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• pp.99-109
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• 2022

Powder flowability is critical in additive manufacturing processes, especially for laser powder bed fusion. Many powder features, such as powder size distribution, particle shape, surface roughness, and chemical composition, simultaneously affect the flow properties of a powder; however, the individual effect of each factor on powder flowability has not been comprehensively evaluated. In this study, the impact of particle shape (sphericity) on the rheological properties of Ti-6Al-4V powder is quantified using an FT4 powder rheometer. Dynamic image analysis is conducted on plasma-atomized (PA) and gas-atomized (GA) powders to evaluate their particle sphericity. PA and GA powders exhibit negligible differences in compressibility and permeability tests, but GA powder shows more cohesive behavior, especially in a dynamic state, because lower particle sphericity facilitates interaction between particles during the powder flow. These results provide guidelines for the manufacturing of advanced metal powders with excellent powder flowability for laser powder bed fusion.

• Journal of Ecology and Environment
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• v.33 no.3
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• pp.205-216
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• 2010

This research identified a disturbance regime caused by wild boar in a mature Quercus mongolica forest and analyzed the impact of this disturbance on the structure and distribution of herbaceous plants in Mt. Jeombong, Korea. We demonstrate that disturbance by wild boar was most frequent from winter to early spring, but also occurred year round. Areas which were frequently disturbed by wild boar included the mountain ridge, the mild slope on the north face, and sites with high concentration of Erythronium japonicum. The disturbance cycle by the wild boar in this region was estimated at approximately 2.8 years. The wild boar's reduced the community's species diversity and herbaceous coverage, and increased its evenness. This disturbance reduced the coverage of spring ephemeral; Veratrum nigrum var. ussuriense, Symplocarpus niponnicus, Anemone koraiensis and Corydalis turtschaninovii were particularly sensitive. In addition, summer green herbaceous plants such as Astilbe chinensis, Ainsliaea acerifolia, Meehania urticifolia, and Pimpinella brachycarpa were sensitive to the wild boar's. It was found that wild boar ate E. japonicum most selectively of all plants in this investigation area. In conclusion, together with micro-topography, wind, formation of gaps of a forest and rearrangement of litter layer, wild boar's disturbance is an important factor influencing the dynamic changes of an herbaceous community in a mature temperate hardwood forest.

• Journal of Drive and Control
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• v.14 no.3
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• pp.40-49
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• 2017

This study presents an online estimation of an excavator's rotational inertia by using recursive least square with forgetting. It is difficult to measure rotational inertia in real systems. Against this background, online estimation of rotational inertia is essential for improving safety and automation of construction equipment such as excavators because changes in inertial parameter impact dynamic characteristics. Regarding an excavator, rotational inertia for swing motion may change significantly according to working posture and digging conditions. Hence, rotational inertia estimation by predicting swing motion is critical for enhancing working safety and automation. Swing velocity and damping coefficient were used for rotational inertia estimation in this study. Updating rules are proposed for enhancing convergence performance by using the damping coefficient and forgetting factors. The proposed estimation algorithm uses three forgetting factors to estimate time-varying rotational inertia, damping coefficient, and torque with different variation rates. Rotational inertia in a typical working scenario was considered for reasonable performance evaluation. Three simulations were conducted by considering several digging conditions. Presented estimation results reveal the proposed estimation scheme is effective for estimating varying rotational inertia of the excavator.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.3
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• pp.409-420
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• 2002

This paper proposed a technique of structural re-analysis for the evaluation of dynamic responses of bridge structure under moving loads using experimental modal results. For successful structural re-analysis, it is required to have accurate estimation techniques of the modal characteristics of bridge structures. The natural frequencies and mode shapes were identified by direct fourier analysis techniques and damping ratios by the random decrement method, respectively. An interpolation method was also proposed for the extension of mode shape measured on limited DOFs. Second, the structural reanalysis was performed using moving mass model and identified modal parameters. The results from the reanalysis show that the proposed technique is very reasonable to evaluate the actual behavior of bridge structures under moving loads.