• ETRI Journal
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• v.44 no.5
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• pp.780-793
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• 2022

Large-scale ontology management is one of the main issues when using ontology data practically. Although many approaches have been proposed in relational database management systems (RDBMSs) or object-oriented DBMSs (OODBMSs) to develop large-scale ontology management systems, they have several limitations because ontology data structures are intrinsically different from traditional data structures in RDBMSs or OODBMSs. In addition, users have difficulty using ontology data because many terminologies (ontology nodes) in large-scale ontology data match with a given string keyword. Therefore, in this study, we propose a (graph database-based ontology management system (GOMS) to efficiently manage large-scale ontology data. GOMS uses a graph DBMS and provides new query templates to help users find key concepts or instances. Furthermore, to run queries with multiple joins and path conditions efficiently, we propose GOMS encoding as a filtering tool and develop hash-based join processing algorithms in the graph DBMS. Finally, we experimentally show that GOMS can process various types of queries efficiently.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.354-360
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• 2009

The demands for large-scale construction projects such as Mega-projects are largely increasing due to the rapid growth of increasing populations as well as the need to replace existing buildings and infrastructure. Increasing costs of materials, supplies, and labors require the first cost estimates at the preliminary planning stage to be as accurate as possible. This paper presents the results obtained from the survey on evaluating nine critical success factors that influence the accurate first cost estimates for large-scale projects from practical experiences. It then examines the current cost structures of construction companies for large-scale projects, followed by the causes for cost and schedule overrun. Twenty completed surveys were collected and the Analytic Hierarchy Process was applied to analyze the data. The results indicate that technology issues, the contract type, and social and environmental impacts are the significant leading factors for accurate first cost estimates of large-scale construction projects.

• Korean Journal of Computational Design and Engineering
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• v.17 no.2
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• pp.123-131
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• 2012

The requirements for computational resources to perform the structural analysis are increasing rapidly. The size of the current analysis problems that are required from practical industry is typically large-scale with more than millions degrees of freedom (DOFs). These large-scale analysis problems result in the requirements of high-performance analysis codes as well as hardware systems such as supercomputer systems or cluster systems. In this paper, the pre- and post-processing system for supercomputing based large-scale structural analysis is presented. The proposed system has 3-tier architecture and three main components; geometry viewer, pre-/post-processor and supercomputing manager. To analyze large-scale problems, the ADVENTURE solid solver was adopted as a general-purpose finite element solver and the supercomputer named 'tachyon' was adopted as a parallel computational platform. The problem solving performance and scalability of this structural analysis system is demonstrated by illustrative examples with different sizes of degrees of freedom.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.1
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• pp.47-56
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• 2015

Energy consumption in buildings is currently a real problem. That is why both assessment of energy performance and effective energy management including renewable energy system are essential. Thus, this paper focuses on a case study to analyze the energy performance and cooling & heating energy saving of a large scale shopping store in Daejeon city. The reference building is simulated by using TRNSYS dynamic simulation tool to examine its annual energy consumption. For annual energy analysis of building, one year energy consumption is surveyed in the field. The related study is carried out in large scale shopping store to investigate the energy consumption and energy use trend of heating, cooling, hot water, lighting, ventilation, equipments and other. The evaluation of energy performance of the geothermal heat pump system installed in a large scale shopping store is also analyzed by TRNSYS tool. From simulation results, it evaluated that the geothermal heat pump system is effective energy savings method in large scale shopping store.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.91-94
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• 2005

With increasing demands for large-scale micro-optical components in the field of digital display, the establishment of large-scale fabrication technology fur polymeric patterns has become a priority. The starting point of any polymer replication process is the mold, and the mold often has flat surface. However, It is very hard to replicate large-scale micro patterns using the flat mold, because the cost of large-scale flat mold was very high, and some uniformity and releasing problems were often occurred in large scale flat molding process. In this study, a UV roll imprinting system to overcome the financial and fabrication issues of large-scale pattern replication process was designed and constructed. As a practical example of the system, a lenticular lens with radius of curvature of $223{\mu}m$ and pitch of $280{\mu}m$, which was used to provide wide viewing angle in projection TV, was designed and fabricated. The roll stamper was fabricated using direct machining process of aluminum roll base. Finally, the shape accuracy and uniformity of roll imprinted lenticular lens sheet were measured and analyzed.

• Journal of the Korean Solar Energy Society
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• v.30 no.6
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• pp.44-49
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• 2010

The purpose of this study is to analyze the situation of energy consumption and its characteristics in large scale store. The related survey is carried out in large scale store to investigate the energy consumption and energy use trend of heating, cooling, hot water, lighting, ventilation, equipments and others. The area of large scale discount store is about $65000m^2$, located in Daejeon. For Annual Energy Analysis of building, We surveyed used energy for 1 year and simulated using a building energy simulation(TRNSYS 16). The results of this study are as follows. 1)The amount of annual total energy consumption are 18615.244MWh/yr(286.4KWh/$m^2yr$), The rate of heating, cooling and base energy(for hot water, lighting, ventilation, equipments, cooking and others) is 3054MWh/yr(47kWh/$m^2yr$), 5660.09MWh/yr(87.08kWh/$m^2yr$), 9900.47MWh/yr(152.31KWh/$m^2yr$) respectively. The total used energy is higher than others building in Korea. Especially, The energy consumption of large scale store is very depends on operating period and pattern such as space temperature, occupancy, lighting system, equipments operating schedule and etc.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.4
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• pp.1100-1122
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• 2023

Scheduling user-submitted cloud tasks to the appropriate virtual machine (VM) in cloud computing is critical for cloud providers. However, as the demand for cloud resources from user tasks continues to grow, current evolutionary algorithms (EAs) cannot satisfy the optimal solution of large-scale cloud task scheduling problems. In this paper, we first construct a large- scale multi-objective cloud task problem considering the time and cost functions. Second, a multi-objective optimization algorithm based on multi-factor optimization (MFO) is proposed to solve the established problem. This algorithm solves by decomposing the large-scale optimization problem into multiple optimization subproblems. This reduces the computational burden of the algorithm. Later, the introduction of the MFO strategy provides the algorithm with a parallel evolutionary paradigm for multiple subpopulations of implicit knowledge transfer. Finally, simulation experiments and comparisons are performed on a large-scale task scheduling test set on the CloudSim platform. Experimental results show that our algorithm can obtain the best scheduling solution while maintaining good results of the objective function compared with other optimization algorithms.

• Architectural research
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• v.23 no.2
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• pp.19-28
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• 2021

Reduction in competence makes older adults with dementia more sensitive to the influence of the physical environment. The aim of the longitudinal study was to examine whether residents with dementia in long-term facilities with variability in physical environmental characteristics in Vancouver (N= 11), Canada and Stockholm (N=13), Sweden had a difference in their quality of life (QoL). QoL was assessed using Dementia Care Mapping tool three times over one year for the reliability of data. The results of the study demonstrated that the residents with dementia living in a homelike and positive stimulating setting showed less withdrawn behaviors and a higher level of well-being compared to those in a large-scale institutional setting. This study also found that the residents living in a large-scale institutional environment spent more monotonous times than the other groups, which may be to provision of fewer structured activity programs or less social interaction with neighbors or staff members. Residents living in a large-scale institutional setting in Canada showed so far as five times more agitated/ distressed behaviors and twice more withdrawal compared to the ones living in a small-scale homelike setting in Sweden. The study supports that the large-scale institutional environment was considerably associated with levels of lower quality of life among the residents with dementia.

• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.553-556
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• 2004

We present a new model for the generation of magnetic fields on large scales occurring at the end of cosmological reionisation. The inhomogeneous radiation provided by luminous sources and the fluctuations in the matter density field are the major ingredients of the model. More specifically, differential radiation pressure acting on ions and electrons gives rise to electric currents which induce magnetic fields on large scales. We show that on protogalactic scales, this process is highly efficient, leading to magnetic field amplitudes of the order of $10^{-1l}$ Gauss. While remaining of negligible dynamical impact, those amplitudes are million times higher than those obtained in usual astrophysical magnetogenesis models. Finally, we derive the relation between the power spectrum of the generated field and the one of the matter density fluctuations. We show in particular that magnetic fields are preferably created on large (galactic or cluster) scales. Small scale magnetic fields are strongly disfavoured, which further makes the process we propose an ideal candidate to explain the origin of magnetic fields in large scale structures.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.6A
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• pp.635-642
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• 2008

We propose the Optimum Power Allocation (OPA) scheme for Distributed Antenna Systems(DAS) in the time-varying Rayleigh fading channel. Recently, the OPA schemes which uses the Channel State Information (CSI) including a small scale (fast) fading have been proposed. However, the channel is changing vary fast over time due to small scale fading, therefore Bit Error Rate (BER) increases. Because of this reason, we derive the OPA for minimizing BER in DAS, which only uses a large scale fading to CSI and excepts a small scale fading. The simulation results show that the proposed OPA achieves better BER performance than conventional OPA considering a small scale fading in time-varying Rayleigh fading channel, and also has similar performance in Rayleigh flat-fading environment. The BER performance of proposed OPA which derived in Rayleigh fading channel is similar to minimum BER of Ricean fading channel which has small Line-of-Sight (LOS).