• Journal of Power Electronics
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• v.17 no.5
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• pp.1288-1297
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• 2017

The estimation of the remaining useful life (RUL) of lithium-ion (Li-ion) batteries is important for intelligent battery management system (BMS). Data mining technology is becoming increasingly mature, and the RUL estimation of Li-ion batteries based on data-driven prognostics is more accurate with the arrival of the era of big data. However, the support vector machine (SVM), which is applied to predict the RUL of Li-ion batteries, uses the traditional single-radial basis kernel function. This type of classifier has weak generalization ability, and it easily shows the problem of data migration, which results in inaccurate prediction of the RUL of Li-ion batteries. In this study, a novel multi-kernel SVM (MSVM) based on polynomial kernel and radial basis kernel function is proposed. Moreover, the particle swarm optimization algorithm is used to search the kernel parameters, penalty factor, and weight coefficient of the MSVM model. Finally, this paper utilizes the NASA battery dataset to form the observed data sequence for regression prediction. Results show that the improved algorithm not only has better prediction accuracy and stronger generalization ability but also decreases training time and computational complexity.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.11
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• pp.5357-5381
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• 2018

Cloud computing offers a wide range of on-demand resources over the internet. Utility-based resource allocation in cloud data centers significantly increases the number of cloud users. Heavy usage of cloud data center encounters many problems such as sacrificing system performance, increasing operational cost and high-energy consumption. Therefore, the result of the system damages the environment extremely due to heavy carbon (CO2) emission. However, dynamic allocation of energy-efficient resources in cloud data centers overcomes these problems. In this paper, we have proposed Energy and Service Level Agreement (SLA) Aware Resource Allocation Heuristic Algorithms. These algorithms are essential for reducing power consumption and SLA violation without diminishing the performance and Quality-of-Service (QoS) in cloud data centers. Our proposed model is organized as follows: a) SLA violation detection model is used to prevent Virtual Machines (VMs) from overloaded and underloaded host usage; b) for reducing power consumption of VMs, we have introduced Enhanced minPower and maxUtilization (EMPMU) VM migration policy; and c) efficient utilization of cloud resources and VM placement are achieved using SLA-aware Modified Best Fit Decreasing (MBFD) algorithm. We have validated our test results using CloudSim toolkit 3.0.3. Finally, experimental results have shown better resource utilization, reduced energy consumption and SLA violation in heterogeneous dynamic cloud environment.

• Geophysics and Geophysical Exploration
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• v.1 no.1
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• pp.8-18
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• 1998

In exploration seismology, the Kirchhoff hyperbola has been successfully used to migrate reflection seismo-grams. The mathematical basis of Kirchhoff hyperbola has not been clearly defined and understood for the application of prestack or poststack migration. The travel time from the scatterer in the subsurface to the receivers (exploding reflector model) on the surface can be a kinematic approximation of Green's function when the source is excited at position of the scatterer. If we add the travel time from the source to the scatterer in the subsurface to the travel time of exploding reflector model, we can view this travel time as a kinematic approximation of the partial derivative wavefield with respect to the velocity or the density in the subsurface. The summation of reflection seismogram along the Kirchhoff hyperbola can be evaluated as an inner product between the partial derivative wavefield and the field reflection seismogram. In addition to this kinematic interpretation of Kirchhoff hyperbola, when we extend this concept to shallow refraction seismic data, the stacking of refraction data along the straight line can be interpreted as a measurement of an inner product between the first arrival waveform of the partial derivative wavefield and the field refraction data. We evaluated the Kirchhoff hyperbola and the straight line for stacking the refraction data in terms of the first arrival waveform of the partial derivative wavefield with respect to the velocity or the density in the subsurface. This evaluation provides a firm and solid basis for the conventional Kirchhoff migration and the straight line stacking of the refraction data.

• Proceedings of the KSRS Conference
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• v.1
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• pp.352-355
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• 2006

In this study, the seasonal and inter-annual variation of sea surface current in the Gulf of Thailand were revealed through the use of WOD temperature and salinity data and monthly sea surface dynamic heights (SSDH) from TOPEX/Poseidon and ERS-2 altimetry data during 1995-2001. The mean dynamic height and mean geostrohic current were derived from the climatological data while SSDH data gave monthly dynamic heights and their geopstrophic currents. The mean geostrophic current showed strong southward and westward flow of South China Sea water along the gulf entrance. Counterclockwise eddy in the inner gulf and the western side of the gulf entrance associated with upwelling in the area. Seasonal geostrophic currents show basin-wide counterclockwise circulation during the southwest monsoon season and clockwise circulation during the northeast monsoon season. Upwelling was enhanced during the southwest monsoon season. The circulation patterns varied seasonally and inter-annually probably due to the variation in wind regime. And finally we found that congregation, spawning, and migration routes of short-bodied mackerel conform well with coastal upwelling and surface circulation in the gulf.

• International Journal of Advanced Culture Technology
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• v.12 no.3
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• pp.140-147
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• 2024

Oil and gas industry is a unique sector with complex activities, long supply chains and strict rules for the business. It is important to use enterprise resource planning (ERP) systems to address these challenges as it helps in simplifying operations, improving efficiency and facilitating evidence-based decision making. Nonetheless, successful integration of ERP systems in this industry involves careful planning, customization and alignment with specific business processes including regulatory requirements. Several critical factors, such as strong change management, support of top managers and training that works have been identified in the study. Amongst the hurdles are employee resistance towards the changes, data migration complications and integration with existing systems. Nonetheless, NOCL's ERP implementation resulted in significant improvements in operating efficiency, better data visibility and compliance management. It also led to a decrease in financial reporting timeframes, more accurate inventory tracking and improved decision-making capabilities. The study provides useful insights on how to optimize oil and gas sector ERP implementations; key among them is practical advice including strengthening change management strategies, prioritizing data security and collaborating with ERP vendors. The research highlights the importance of tailoring ERP solutions to specific industry needs as well as emphasizes the strategic role of ongoing monitoring/feedback for future benefits sustainability.

• Geophysics and Geophysical Exploration
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• v.14 no.3
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• pp.227-233
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• 2011

Attention has been focused on geothermal energy as an alternative energy because it is continuously operable without external supply. Most of geothermal anomalies in Korea are related to deep circulation of groundwater through a fracture system in granite area. Therefore it is very important to understand the distribution of the fracture system which is the main channel of ground water. In this research, we constructed the velocity models with a fracture system and the layered sediments, respectively, and generated synthetic data sets with them to verify the presented vertical seismic profiling (VSP) preprocessing scheme. We compared the results from conventional VSP preprocessing flow to those from VSP preprocessing flow considering fracture system. We noticed that the preprocessing flow considering fracture system retains more sufficient signal including down-going wave than conventional preprocessing. In addition, we applied 3D VSP prestack phase screen migration to the preprocessed reversed VSP (RVSP) data from Seokmo Island so that we were able to image fracture structure of the geothermal site in Seokmo Island.

• Journal of Life Science
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• v.31 no.9
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• pp.787-795
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• 2021

Eupatorium chinensis var. simplicifolium (EUC) has anti-inflammatory and antioxidant effects. Young sprouts of EUC have been used as food for a long time, and the whole EUC plant has been used as an herbal remedy in oriental medicine. Arteriosclerosis, or chronic inflammation in arterial vessels, is a cardiovascular disease and is involved in various disorders. Cardiovascular diseases such as restenosis and neuropathic hyperplasia are mainly caused by abnormal growth and movement due to multiple growth factors in vascular smooth muscle cells (VSMCs). Platelet-derived growth factor (PDGF) is a mitogen released from damaged vessel walls and is involved in the proliferation and migration of VSMCs. To determine the effects of EUC on the abnormal proliferation and migration of VSMCs, the present study investigated intracellular signaling pathways in PDGF-BB-induced VSMCs treated with and without EUC. Pretreating PDGF-BB-induced VSMCs with EUC tended to effectively decrease cell proliferation and migration. Subsequently, the intracellular growth-related signaling pathways of AKT, phospholipase C gamma (PLC-γ), and mitogen-activated protein kinase (MAPK) were investigated using western blotting to confirm inhibited phosphorylation. Furthermore, flow cytometry data showed that EUC blocked the cell cycle of VSMCs. These results suggest that EUC can inhibit the proliferation and migration of VSMCs by controlling the cell cycle and growth factor receptors. Furthermore, this indicates that EUC can be used as a preventative against cardiovascular disease resulting from abnormal proliferation and migration of VSMCs.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.610-612
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• 2008

Piston cores retrieved from the eastern part of the deep-water Ulleung Basin were analyzed to access the potential of hydrocarbon gas generation and natural gas hydrate (NGH) formation. Seismic data acquired in the study area were also analyzed to determine the presence of hydrocarbon gas and/or NGH, and to map their distribution. Core analyses revealed high total organic carbon (TOC) contents which favor hydrocarbon generation. The cores recovered from the southern study area showed the sufficient residual hydrocarbon gas concentrations for the formation of significant NGH. These cores also showed the cracks developed parallel to the bedding that suggest significant gas content in situ. A number of seismic blanking zones were observed on seismic data. They are identified as vertical to sub-vertical chimneys caused by the upward migration of pore fluid or gas, and containing of free gas and/or NGH. Often, they are associated with velocity pull-up structures that are interpreted to be the result of high-velocity NGH. The seismic data also showed several bottom-simulating reflectors (BSRs) that are associated with overlying NGH and underlying free gas. The distribution of blanking zones and BSRs would be impacted by the lateral differences of upward methane fluxes.

• Korea journal of population studies
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• v.9 no.1
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• pp.69-88
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• 1986

The purpose of the present study is to find out and analyze the degree of population concentration of 10 selected cities. The data used for the present study were derived from the Government publications including the population and Housing Census Reports from 1966 through 1980 and the Korea Urbanic Yearbooks from 1969 through 1981. The major findings of the study were summarized as follows: The data revealed that changes of population size were more rapidly proceeded in Seoul than any other city and regarding to population composition, these selected cities had more male population than female population. The proportion of the productive age group of these selected cities were found to be higher than that of whole country each year, especially the proportion 20∼24 aged group was higher in 1980 than any other year. The number of net migrants in these cities during last 20 years, 1960∼80 was 910, 656 as Seoul obtained the largest net migrants and among the selected cities, Seoul, Busan, Daegu, Incheon, Daejeon and Jeonju had a big change in volume of net migration population, especially in 30∼39 aged group in 1980. According to Gini Concentration Ratio and Index of Concentration, the population concentration was the highest in 1980 and the population concentration was intensively accelerated during 1966∼ 1970.

• The Transactions of the Korea Information Processing Society
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• v.7 no.1
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• pp.1-11
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• 2000

Up to the present, many GIS logical data models have been proposed to incorporate time dimension into traditional 2-dimensional (2D space) GIS databases. However, these models are difficult to implementation of multi-dimensional GIS and have problems of significant data redundancy and search performance. This paper proposes a new storage strategy and a separate storage structure, that is composed of current database and past database, in order to reduce data redundancy and improve search performance of temporal query. Also we design moving algorithm for migration from current database to past database, and design efficient search algorithm for temporal query.